Ron Allen's soil and water pages
 
   
 
 
SOIL AND WATER IN THE NEW FOREST AND THE VALLEY MIRES

INTRODUCTION

I have worked on many sites in the New Forest since 1980. Between 1980 and 1986, I was mapping the soils of the major part of the New Forest and also undertaking peat assessments for the England and Wales National Peat Survey. In 1984, I organised site visits to the New Forest as part of the annual field conference of the British Society of Soil Science.

Our very first commercial project in 1986 was to prepare set of lecture notes on the Beauleigh River Catchment, typed out by Mary because our first computer had yet to arrive. Since that time, we have worked on a variety of New Forest sites, especially the internationally important mire systems. These sites have included Bagnum Bog, part Kingston Great Common National Nature Reserve, to explore a water management system and also Picket Post in the central Forest to advise on the best way to discharge surface road water into the Forest to minimise erosion and ecological impact. I also examined many mire systems for the Forestry Commission as the basis for their mire restoration scheme.

The sections that follow provide a summary of the physical, soil and hydrological setting of the New Forest and its mires and is adapted from various project reports and a review undertaken for the Wetland Research Group at Sheffield University under contract from English Nature.

  • 1.0 VALLEY MIRES
  • 2.0 NEW FOREST LANDFORM
  • 3.0 GEOLOGY OF THE NEW FOREST
  • 4.0 SOILS OF THE NEW FOREST
  • 5.0 HYDROLOGY OF THE NEW FOREST
  • 6.0 HYDROGEOLOGY OF THE NEW FOREST
  • 7.0 HYDROLOGY OF THE MIRE SYSTEMS
  • 8.0 EXAMPLE MIRE SYSTEMS
  • 9.0 REFERENCES

1.0 THE VALLEY MIRES

Colin Tubbs in The New Forest (Collins 1986) explains that the New Forest Mires:

  • Are of established international importance providing some of the best examples of this habitat known in Europe;
  • Have not suffered appreciable damage and form virtually intact ecosystems in continuity with heathland and woodland catchments;
  • Occur on valley bottoms and below hill-slope seepages;
  • Are divided into some ninety separate mires distributed in about twenty separate catchments;
    and
  • Exhibit complex gradations of hydrological and chemical conditions resulting in an equal complexity of plant communities.
Brewis et.al. (1996) indicates that the presence of 2900ha of wet heath and valley mire makes the New Forest the largest area of acid lowland Sphagnum mires (valley bogs) in Europe.

2.0 NEW FOREST LANDFORM

The distribution and character of valley mires in the New Forest is directly related to the form and distribution of the valley system within the catchment of each mire.

Fisher (1975) describes the New Forest as a scarp in the northwest reaching about 127mAOD and from which the land surface descends in a series of terrace flats, separated by bluffs, SE to the Solent and SW to the river Avon. The preservation of the scarp and terraces is usually attributed to a discontinuous cover of permeable Pleistocene sandy gravel, most extensive below 80m AOD, which overlies Tertiary clays and sands. There has also been considerable mass movement of gravel from the New Forest Terraces.

Tubbs (1986) indicates that the Forest is dominated by eleven gravel terraces between 128m and 5m. For 13km along the north-west boundary there is a north-easterly facing, gravel capped escarpment at 120-128m including the Forest’s high point at Black Bush Plain and from where the land descends south and east to the Solent and south and west to the Avon in a series of terraces separated by wide, eroded valleys and hollows.

Clarke and Allen (1986) describe the New Forest as a series of dissected river terraces, descending in altitude to the south and west and cut into soft Tertiary sands, loams and clays. Remnants of the higher northern terraces, comprising poorly sorted loamy and clayey flinty gravels, form ridges bounded by steep-sided valleys. The lower terraces are broad, flat or gently undulating plains dissected by shallow valleys and covered by flinty, sandy and stoneless loamy deposits.

Newbould (1960) considered that the streams in the valleys are eroded nearly to base level causing slow flow and that they were cut by larger streams at a time of higher rainfall.

Careful examination shows that all of the mires have their individual landscape character and while some mires are contained within relatively simple valley systems, others are contained within landscapes of considerable topographic complexity.

3.0 GEOLOGY OF THE NEW FOREST

The geological character of the New Forest controls to a great extent the landform, the distribution of soils and how water flows into the mires. Tubbs (1986) indicates that the New Forest is in the centre of a chalk syncline known as the Hampshire Basin containing Tertiary sedimentary strata dipping gently at 1-2 degrees to the south and overlain by superficial deposits of gravel on terraces and plateau surfaces, the southernmost terraces being overlain by brickearth. The Tertiary strata become younger at outcrop from north to south. Because of the low angle of dip, the detailed distribution of any one Tertiary stratum is closely related to landform.

In many parts of the New Forest, the geology is very complex. Individual formations vary both laterally and with depth and many can be lithologically varied on a small scale. Some of these deposits are base-poor and others are base-rich.

While the Forest is underlain by soft Tertiary strata, these are almost everywhere covered by Quaternary deposits of considerable complexity and including terrace deposits on level surfaces, head deposits on slopes, and alluvium and peat on low-ways and valley floors.

Sources of information

A general introduction to the geology of the wider area is contained in:
Melville R V, and Freshney E C, 1982. British Regional Geology: The Hampshire Basin. London: HMSO for Institute of Geological Sciences.

The most recent geological mapping and memoir information is:

  • Northeast New Forest
    Sheet 315 Southampton, 1:50 000 Series British Geological Survey 1987 with revised stratigraphy
    Edwards R A and Feshney E C, 1987 Geology of the country around Southampton, Mem. Br. Geol. Surv. Sheet 315 (England and Wales)
  • Northwest New Forest
    Sheet 314 Ringwood, 1:50 000 reprint of 1902 mapping at 1” to mile, Geological Survey of Great Britain 1976
  • Southeast New Forest
    Sheet 330 Lymington, 1:50 000 reprint of 1893 and 1963 mapping at 1” to mile, Geological Survey of Great Britain 1975
  • Southwest New Forest
    Sheet 329 Bournemouth, 1:50 000 Series British Geological Survey 1991 with revised stratigraphy
    Bristow, C R, Freshney E C, and Penn I E. 1991 Geology of the Country around Bournemouth. Mem. Br. Geol. Surv, Sheet 329 (England and Wales).
Additional detail for the southwest and southeast New Forest is provided in:
Mathers S J, 1982. The sand and gravel resources of the country around Lymington and Beaulieu, Hampshire, Institute of Geological Sciences Mineral Assessment Report 122

Stratigraphy of the deposits

Combining information from the above documents the deposits in the New Forest can be divided into:

Drift Deposits comprising:
  • small areas of peat;
  • linear strips of alluvium;
  • irregular areas of head and head gravel; and
  • larger areas of older
    and
  • more recent flinty terrace deposits.
Solid Deposits which in the New Forest are wholly Palaeogene (Lower Tertiary) in age and comprising variable sandy and clayey strata within the:
  • Headon Formation;
  • Barton Group
    and
  • Bracklesham Group.
These deposits (Table 1) are lithologically very variable. Small areas of peat and alluvium are restricted to valley bottoms, while the terrace deposits occupy either ridge tops (in the northern Forest) or form wide level terraces (in the southern Forest).

Some Paleogene deposits are clearly more clayey (eg. those in the Headon Beds, Barton Clay and the Wittering Formation), others are more sandy (eg. Barton Sand and part of the Earnley Sand). Other strata are very variable with clays, sandy clays, clayey sands and silts that often rapidly alter in lithology, both vertically and laterally.

The Tertiary sandy strata are almost always of fine and very fine sands and base-poor. Clayey strata are generally recognised as having at least moderate levels of bases and those on the Headon Beds are often shelly and very rich in bases, especially calcium.

4.0 SOILS OF THE NEW FOREST

Introduction to the soils

The character of the soils is important in determining the way water flows out of the geological substrates and into the mires. Some soils are permeable, others slowly permeable, while others have complex conditions that control the flow and chemistry into the mires on the local scale. The distribution of mineral and organic soils is fundamental to the way the mires operate and the development and characteristics of their plant and animal communities. Despite the importance of soil information, little research has been undertaken into the detailed distribution of soils in relation to the valley mires.

Soil is taken as that material forming the uppermost 1.5m of the land surface and has resulted from the action of soil forming processes on various geological parent materials. Soil types are defined according to the sequence and characteristics of layers (horizons) and classified by grouping soils with different sequences of layers. Soils vary according to their water regime, their texture, their chemistry and the presence or absence of a range of mineral, carbonatic and peaty materials.

Individual soil types are known as soil series and are given names based on where they were first described. Individual soil series tend to be associated with other broadly similar soil series according to their parent material, landscape position or other factor. These groupings of soils are mapped as soil associations and named after the most abundant soil series and given a number code based on the classification of the main soils. Soil series are shown on large scale maps and soil associations are shown on small scale maps.

There are no detailed published soil maps covering the New Forest, but the whole area is shown on Sheet 6 South East England of the 1:250 000 scale Soils of England and Wales. The soils of each association are described in outline on the separate Legend to the Soil Map of England and Wales and in more detail in the explanatory Bulletin 15 of the Soil Survey of England and Wales Jarvis et.al (1984).

None of the peat soils of the mires are shown on this map because they are too small to be shown at that scale. They are however described as part of individual soil associations in Bulletin 15 and the main areas of peat are shown on the 1:100 000 scale map, Lowland Peat in England and Wales and described in Burton and Hodgson (Eds) 1987. However, the nature of the mineral soils of the catchment is crucially important to understanding the function of the mires in their wider landscape and historical and pedological setting.

The soils of the wider area around Southampton, including the New Forest, are described in Jarvis and Findlay (Eds) 1984. The introductory Section 1 takes material from the 1:250 000 soil map. Section 2 (Allen and Staines 1984) describes the New Forest Soils in much greater detail.

General soil characteristics

The New Forest is a major area of semi-natural soils affected to the greater extent only by pre-historic and historic changes in vegetation and cultivation practices, primarily woodland to heathland. As a result the Forest displays continuous sequences of soil with all their interrelated facets, such as soil water regimes and interactions with plant communities, intact. This is the one place in the southern UK where the interaction of soils and their geological substrates can be seen in relation to vegetation, and to valley mires in particular.

Allen and Staines (1984) indicate that most of the New Forest soils are very acid, have impermeable layers and are seasonally waterlogged. Humose or peaty soils occur in valley bottoms, but freely drained soils are restricted to small areas in the west.

Key facts of the soils affecting the character of the valley mires are:
  • their general slow permeability and seasonal waterlogging with only small areas of better drained soils;
  • included areas of better drained soils often affected by high perched groundwater; and
  • their great variability over very short distances.
  • Clarke and Allen (1986) divide the soils into the following main groups:
  • Soils on the terraces are mainly podzolic, but most have slowly permeable subsoils causing seasonal surface waterlogging.
  • Soils on the Tertiary clays and compact loams are seasonally waterlogged surface water gleys.
  • Soils on the smaller areas of permeable sands are well-drained podzols.
  • Soils on slopes adjacent to the terraces are in heterogeneous loamy or sandy variably flinty drift with a variety of water regimes and soil types.
Main soil types

Examination of the soil map and legend shows that the Forest has:

A. Large areas of soils most affected by seasonal surface waterlogging:
  • A very large area of slowly permeable mostly loamy over clayey seasonally waterlogged soils on drift over Tertiary deposits (711g/h Wickham Association); within which are
  • Smaller areas of leached and podzolised sandy and loamy over clayey seasonally waterlogged and more permeable soils, locally affected by ground water over Tertiary sands, loams and clays (643a Holidays Hill Association); closely associated with
  • Irregular areas of leached and podzolised coarse loamy over clayey soils, usually with slowly permeable subsoil horizons on Plateau Gravel and terrace drift (643c Bolderwood Association).
B. Small and large areas of soils mostly affected by groundwater

  • Disparate small areas in the north and large continuous areas in the south of variable loamy flinty permeable soils on river terrace gravels, usually with high groundwater (841b Hurst Association).
C. Small areas of well or moderately well drained soils

  • Small areas with mainly well drained leached and podzolised sandy and loamy soils on Tertiary sands and with some areas affected by groundwater in basins and valleys (631c Shirrell Heath 1 Association);
  • Small areas of deep loamy soils variously slightly affected by either surface water or groundwater mostly on Tertiary deposits (572j Bursledon Association).
Soil Associations

Allen and Staines (1984) provide detailed descriptions of the main New Forest soils and summarise the individual associations as follows:

Wickham Associations, surface water gley soils, are most extensive. The dominant Wickham and Kings Newton soils have thin fine or coarse loamy layers in thin Head over slowly permeable clayey subsoils in Barton Clay, and in clayey or fine loamy strata within the Bracklesham Group and Headon Formation. More permeable soils, such as the coarse loamy Curdridge series, occur locally. On the Barton Clay, wholly clayey Denchworth series soils are common.

Holidays Hill Association has stagnogley podzols on Barton Sands, sandy formations within the Bracklesham Group, and in associated sandy and loamy Head deposits. Slowly permeable layers or pans cause seasonal waterlogging and standing water occurs on level sites in winter. There are also some freely drained Shirrell Heath series, sandy humoferric podzols, and also permanently waterlogged Isleham series, humic sandy gley soils.

Bolderwood Association is similar in many ways to the Holidays Hill Association although developed on flinty river terrace gravels. Higher terraces that form flat-topped ridges in the north, are often very flinty and dominated by Haldon series which has coarse loamy over clayey layers in flinty drift. Lower terraces, for example at Beaulieu Heath, have coarse loamy over clayey soils in stoneless drift. Well-drained gravelly Southampton series is found locally.

Burseldon Association has mostly moderately well-drained brown soils on Barton Sand and related Head deposits. Fine loamy Bursledon series has slight seasonal waterlogging and coarse loamy Curdridge and Ellingham soils affected by groundwater are most common.

Hurst Association, mainly coarse loamy very stony over gravelly groundwater gley soils, occurs on terraces along the Lymington River north of Brockenhurst.

Peaty soils in raw Sphagnum peat occur in many valley bottoms, although they are too small to be shown at the scale of the 1:250 000 soil map.

Peat soils and deposits

I described the soils and deposits of the New Forest peatlands in Burton and Hodgson Eds. (1987) and in Allen and Staines (1984).

The New Forest mires occupy sinuous valleys cut into flinty plateau drift over a series of terraces descending in height south and west and variously underlain by leached Bagshot and Barton Sands and partly clays of Bracklesham and Barton Beds. Water draining into the mires tends to be acidic, except where it passes through calcareous Headon Beds (Newbould 1960).

Peaty soils tend to occur (Allen and Staines 1984):
  • within Holidays Hill and Wickham Associations;
    and also
  • on seepage steps at the boundary of Bolderwood and Wickham Associations.
The peat deposits consist of a mixture of fibrous, semi-fibrous and amorphous peat variously composed of Sphagnum, Molinia and Phragmites with Eriophorum, Juncus and Carex species. Woody fragments also occur.

In most mires, the peat is less than 1m thick, but locally (as at Cranesmoor) it is up to 5m thick. Valley side seepage zones give rise to small areas of peat usually less than 1m thick.

Mike Clarke provides some peat depths for some New Forest Mires (Clarke M J, Pers.comm. 1985). While Crane’s Moor has up to 5m of peat and Barrow Moor and several other mires have up to 1.5m of peat and most are less than 1m deep and this may be related to drainage.

Most peat soils have raw undecomposed surface layers and are developed in fibrous or semi-fibrous peat. Raw oligofibrous peat soils predominate on open sites, mostly in Molinia, or locally in Sphagnum peat. Peat from Sphagnum and Eriophorum occurs less commonly. Upper layers typically have pH values from 3.6 to 4.8. Below the surface layers, the peat is mostly semi-fibrous and often deeply penetrated by living Molinia roots, the peat may become amorphous at depth.

Raw oligo-amorphous peats occur below alder carr in central tracts of many mires. Raw eutro-amorphous peat soils in grass-sedge peat occur below reed stands and have a pH range of 4.3-5.9. Similar soils with earthy upper layers occur where the mire surface is less wet and dries out in summer. Burton and Hodgson Eds. (1987).

Much work has been done to establish the vegetational history of the New Forest from pollen analysis of the peat deposits (eg. Seagrief 1960, Barber 1975, West 1977).

5.0 HYDROLOGY OF THE NEW FOREST

Background to New Forest Hydrology

The way water behaves in the New Forest is one of the most fundamental characteristics governing the distribution of the valley mires and is itself dependent upon landform, geology and soil characteristics.

An important point is that the hydrology of the mires has changed as the climate and rainfall patterns have changed during the Quaternary. The larger volumes of water that created many of the valleys are now gone. The systems that created the mires are almost certainly no longer operating, and the hydrological system we see today is probably very different to that in earlier times Tubbs (1986) and Newbould (1960).

Mire development appears to have started between about 12500 BP (Church Moor) and 10000BP (Cranesmoor) and is likely to have accelerated during periods of greater runoff from the heathlands that developed by about 3000BP.

Fundamental to the understanding of how mires operate in their wider landscape and geological setting is the ‘water balance’. Gilman (1994) explains that the water balance relates to the significance of various inputs, outputs and storage and especially groundwater inflow, surface inflow, evaporation, groundwater outflow, surface outflow and changes in storage as water levels alter.

Such studies do not appear to have been undertaken for any of the valley mires, probably because they have not been under threat from development or water abstraction of any kind.

Stream Network

Tubbs (1986) explains that the main Forest watershed runs approximately north-south and Cox (2001) provides some additional information. Streams are of low volume for most of the year with sudden increases during food flows. Some discharges are delayed by the peat mires allowing continued flows during the summer months. Stream systems without mires can be dry in some summers.

The streams can be separated as follows:

  • Six westerly flowing deeply incised acidic streams with few tributaries, and which descend to the Avon in wide valleys between long, narrow gravel capped ridges including:
    • Ditchend Brook;
    • Hunckles/Latchmore Brook;
    • Dockens Water;
    • Linwood Brook.
  • Five larger drainage networks and some smaller streams which drain to the south and east including:
    • Blackwater and Cadnam Rivers which drain to the River Test,
    • Bartley Water to the Test Estuary, and
    • Beaulieu and Lymington Rivers to the Solent.
River Avon Catchment

Three main acidic tributaries arise off the New Forest:
Ditchend Brook
Huckles/Latchmore Brook
Dockens Water
Linwood Brook.

Lymington River Catchment

Cox (2001) explains that the Lymington River is ‘near natural’ in terms of flow, geomorphology and transitions to riverine and floodplain habitats and the catchment includes a diversity of valley mires, seepage mires, wet heath and floodplain habitats. The major upper part of the river catchment is within the Tertiary clay and sands and superficial gravel deposits of the New Forest.

The main tributaries are acidic:
Highland Water
Fletchers Water/Blackwater
Bratley Water
Passford Water
Etherise Gutter
Avon Water System.

Beaulieu River Catchment

Another ‘near natural’ river draining extensive areas of woodland, heathland and grassland on Tertiary clay and sands and superficial gravel deposits of the New Forest via a series of acidic tributaries (Cox 2001).

The main tributaries are acidic:
Applemore tributary
Langley Stream
Matley Bog Stream
Penerley tributary
Hatchet stream.

Dark Water Catchment

Drains the Tertiary clays and sands and associated plateau gravels of the southeast corner of the New Forest and including important wetland habitats including valley and seepage mire, wet heath, riverine grassland and floodplain grassland. The main tributary is the acidic Stock Water.

Bartley Water Catchment

Drains the northeast corner of the New Forest to the Test Estuary and passing through semi-natural woodland and heathland. The main tributary is the acidic Dogben Gutter.

River Test Catchment

The Cadnam River tributary of the River Blackwater arises from streams draining a small part of the northern part of the Forest and is acidic and neutral in character.

6.0 HYDROGEOLOGY OF THE NEW FOREST

Background

Hydrogeology is the study of how water moves within geological substrates. A convenient summary of how water flows in the ground is provided in Clarke L 1988.

Water bearing geological formations capable of yielding groundwater are called aquifers. Aquifers allow water sourced from catchments to flow towards and sustain the mires. The way in which water flows through aquifers is partly controlled by the disposition of impermeable or less permeable strata known as aquicludes or aquitards. Aquicludes are geological formations with extremely low permeability. The only stratum to approach the characteristics of an aquiclude in the New Forest is the Barton Clay, although even this will have some slow permeability. Aquitards are geological formations of low permeability but through which leakage of groundwater can occur and in the New Forest will include the Headon Beds and the clay-rich lower horizons in the Older Terrace Deposits.

There is very little information on the hydrogeology of the New Forest in relation to the mires other than contained in the small scale 1979 Hydrogeological Map. This is partly because the New Forest does not contain major aquifers capable of providing for the public water supply.

The Hydrogeological Map of Hampshire and the Isle of Wight (1979) divides the Forest into a number of zones (using a now outdated geological stratigraphy).

  • Areas of mainly impermeable clayey Tertiary deposits of little hydrological significance in the New Forest:
    Headon Beds, interstratified marls, clays and loamy sands with bands of ironstone, limestone and lignite; and
    Barton Clay.

  • Areas of more permeable Tertiary deposits:
    Barton Sands, homogenous fine grained sands with loam and clay horizons at various levels and spring line at the junction to the Barton Clay below;
    Bracklesham Beds, variable clays and sands with loam and lignite horizons with low yields; and
    Bagshot Sands, sands with occasional clays

  • Small areas of fluvial sands and gravels.

  • Areas of flinty Plateau Gravels some of which have supplied [domestic" border=0>
    water locally.

  • Narrow strips of alluvium along valley floors.

    Average Annual Rainfall (1941-1970) is shown on an inset map as being 900mm in the central and higher parts of the Forest, falling to 850mm in the coastal zone and towards the valleys of the Avon and Test to the west and east respectively.
Water Table and Conductivity

Most of the water contained within the more permeable Tertiary and later terrace deposits is perched over the more impermeable strata and depths and persistence of small water tables supplying the mires is dependent upon local topography and geology. In this respect the small-scale distribution of Head deposits can be fundamental to the occurrence of the mires, and especially the seepage mires.

Clarke (1988) explains that groundwater under natural conditions, flows from areas of recharge (normally the aquifer’s outcrop area), to points of discharge such as at springs or rivers. The driving force of this groundwater flow is the ‘hydraulic head’, the difference in level of the ground water surface between the recharge and discharge areas. The flow of water through the saturated zone of an aquifer is represented by the Darcy equation relating the rate of groundwater discharge to the hydraulic conductivity, the hydraulic gradient in the direction of flow, and the cross sectional area through which the flow takes place. The hydraulic conductivity is the rate at which water is transmitted through a unit cross-sectional area of the aquifer.

Hydraulic conductivity varies greatly and Tertiary and Drift Deposits are themselves very variable and alter nearer the surface when they become affected by soil forming processes. Published figures for specific deposits in the New Forest area are probably not available. Scales of values are provided in, for instance, Smedema and Rycroft (1983) and in Wilson (1983).

Smedema and Ryecroft (1983) explain that the hydraulic conductivity of the soil depends mainly on the geometry and distribution of the water filled pores and is low when water has to follow a tortuous path through fine pores. These authors provide some values of hydraulic conductivity for different materials as follows:

  • Coarse gravelly sand 10-50m/day
  • Medium sand 1-5m/day
  • Sandy loam/fine sand 1-3m/day
  • Loam, clay loam, clay, well structured 0.5-2m/day
  • Very fine sandy loam 0.2-0.5m/day
  • Clay loam/clay, poorly structured 0.02-0.2m/day
  • Dense clay, not cracked and no biopores 0.002m/day.
Thomason (1975) provides a classification of Hydraulic conductivity as follows:

  • Hydraulic Range Conductivity
  • Very slow <0.01 m/day
  • Slow 0.01-0.1 m/day
  • Moderately slow 0.01-0.3 m/day
  • Moderately rapid 0.3-1.0 m/day
  • Rapid 1.0-10 m/day
  • Very rapid >10 m/day
Thomason (1975) also suggests that for practical purposes an impermeable horizon has a hydraulic conductivity of at least 1/10 of the adjacent more permeable horizon. This suggests that even small differences in conductivity between different strata can lead to marked changes in soil water regime.

On the basis of these figures (Smedema and Ryecroft (1983) and Thomasson (1975) and using the information above, the different geological strata can be classified in terms of their estimated hydraulic Conductivity Class:

Estimated hydraulic conductivity classes of geological materials in New Forest

Stratum Lithology Estimated
  • Saturated Hydraulic Conductivity Class
    Peat In the mires Moderate where compact Rapid to very rapid where fluid
    Alluvium Along larger valley floors, assumed to be clayey Moderate
    River Terrace deposits Flint gravel with sand Rapid to very rapid
    Older River Gravels Flints in a clayey sand matrix Moderately slow
    Head Gravel Mixed clayey, loamy and sandy Moderately slow to rapid
    Headon Beds Shelly clays, silts and sands Moderately slow
    Becton Sand Well-sorted fine-grained sands Moderately rapid to rapid
    Becton Bunny Member Local development of shelly clay and carbonaceous clayey sand Moderately slow
    Charma Sand Clayey silty sands Moderately slow
    Barton Clay (including sandy strata) Clay and sandy clay with sand seams, locally shelly Very slow
    Selsey Sand Mostly silty sands and with sandy clays locally, with carbonate concretions Moderately slow to moderately rapid
    Marsh Farm Formation Laterally variable carbonaceous laminated clays with thin beds of fine-grained sands; and sands with clay beds and laminae Very slow
    Earnley Sand Fine-grained silty and clayey fossiliferous fine-grained sand and sandy silt Moderately slow to moderately rapid
    Wittering Formation Laminated clays with thin beds of fine sand or silt; interfingering with sands with clay laminae locally Very slow

    7.0 HYDROLOGY OF THE MIRE SYSTEMS

    Mire Types and Formation

    Clarke and Allen (1986) characterise the mires as follows:
    1. The valley mires occur as broad, shallow flush networks in the
    • a. valley bottoms and on
    • b. valley side seepage steps that mark the junction between deposits of contrasting lithology
    2. A wide range of plant communities is represented and the vegetation zonation parallel to, and along, the valley axis reflects both:
    • a. water movement and the
    • b. rate of nutrient flow.
    3. The current and continued existence of the valley mires depends upon groundwater supply, and lateral flow is an important component of the valley mire water budget.

    Tubbs (1986) distinguishes between:
    1. Wet Heath with seasonally waterlogged surface water ferric or humic gleys and gley podzols with peaty surface horizon
    2. Seepage Step Mire with permanently waterlogged peat on impermeable or very slowly permeable clayey head below hillside seepage; and
    3. Valley mire with permanently waterlogged peat over impermeable or slowly permeable valley infill.

    Tubbs (1986) discusses different explanations of mire formation:

    • Mire initiation linked to increased surface run-off following forest clearance;
    • Development of impermeable iron pans following podzolisation after forest clearance;
    • Beaver dams:
    • Impeded of drainage by soliflucted clay plugging a watercourse; and
    • Combination of a poor hydraulic gradient and presence of impermeable fill in valley bottoms coupled with an increase in rainfall, woodland clearance or accidental damming.
    Once formed the water retentive properties of the peat ensures continued growth, especially with the combination of year round waterlogging and the presence of water holding Sphagna.

    Forestry Commission (2002) explains that the typical New Forest’s mires:
    • Are waterlogged, acid, nutrient poor habitats occupying shallow to occasionally deep peats, representative of bogs fond in warmer, dry southern lowlands of Britain; and
    • Have a peat depth often as little as 30cm and usually less than 1m. Unlike northern blanket and raised bogs, deep peats are uncommon in the New Forest.
    FC (2002) estimated that valley mires covered up to 1475 hectares of the New Forest (including 107 hectares of willow carr woodland).

    Valley Mires

    Tubbs (1986) explains that Valley Mires are:

    1. Most extensive in the south of the Forest where valleys are wide and shallow with low valley bottom gradients;
    2. Less common in the north where the valleys are narrower and more deeply incised into the higher terraces and have steeper gradients such that valley mire development is more local, though seepage steps are better developed.

    Valley mires receive nutrients from their catchments and are most concentrated along the axis of flow and least concentrated at mire margins and depending upon the base status of the parent material from which the water derives. For instance:

    1. The central flows of Denny Bog, Matley Bog and Holmsley Bog which receive water from the Headon Beds and Barton Clay are about neutral in reaction; compared with those of
    2. Harvest Slade Bottom, Brackley Bottom and Buckherd Bottom which are fed from sands and gravels and decidedly acidic.

    Francis Rose (1953) considered a representative mire in which:
    • Water flow is most rapid and concentrated and the base status highest, along the axis;
    • Flow rates and base status decline laterally; and
    • There are lateral transitional zones with species-rich communities giving way to more acidic communities, coupled with pools of assorted origin.
    Also systems with more acidic flows.

    The ideal zonation is often modified by bifurcation of flows, differences in flow rate and dispersion through the mire and variations in chemistry and volume of water reaching the mire.

    Newbould (1960) considered that bog formation in the gently sloping New Forest Valleys is associated with surface drainage and that bog development is controlled by hydrology and which in turn depends upon:
    • the volume and composition of water entering the valley;
    • the shape of the valley; and
    • the barriers to free flow.
    In particular, Newbould (1960) thought that the distribution and base-status of water flow to be the most important factor controlling plant distribution in the New Forest Valley Bogs.

    Three main components of bog vegetation were distinguished by Newbould (1960):

    (1) Sphagnum-rich vegetation where there:
    • Is a diffuse flow of base-poor water as at the heads of such narrow valleys as Backley Bottom or Buckherd Bottom;
    • Sites marginal to the main waterflow as in Whitemoor, Cranesmoor or Denny Bog
    • Water in these sites is usually off the Barton Sand or Plateau Gravel.
    (2) Flushed vegetation such as at Cranesmoor and Denny Bog with considerable movement of water of intermediate base status and where there is:
    • fast moving base-poor water (as in the center of Backley Bottom of Buckherd Bottom); or
    • slightly richer water moving more slowly as in Upper Denny Bog or Whitton Bottom; or by
    • a tension zone between base-rich and base-poor water as on Whitemoor or Matley Bog.
    (3) Heavily flushed vegetation where either:
    • the water is definitely base-rich, as on Whitemoor or Matley Bog; or
    • where water is strongly canalized as in Lower Denny Bog.
    Seepage Mires

    Tubbs (1986) explains that mire vegetation also occurs on peat accumulated immediately downslope of hillside seepages and which seepages occur below a step like landform.

    Seepage steps, which commonly occur on steep terraces slopes, arise through the seepage of groundwater above the junction between impermeable and permeable strata (Tuckfield 1973). The irregular landform created allows the accumulation of peat in hollows below the step. Such steps form arcuate lines along the contour of most of the valleys that cut into the higher terraces in the north and west of the Forest and locally on the sides of the lower terraces. They occur most commonly just above the junction of the Barton Clay with the overlying Barton Sand. At the heads of valleys, the steps (and their adjacent mires) are close to the stream but become progressively more distant down stream.

    The typical situation occurs in valleys penetrating the middle and higher terraces. Its incipient development can be seen in the lower terraces of the southern Forest where there may be no more than a wet flush line marked by wet heath plants.

    In the higher valleys, seasonally waterlogged land on plateau surfaces passes to well drained slopes below which is a steep scarp slope leading to an undulating slope composed of slowly permeable slumped material with mire developed in the undulations. Below the irregular slope, the land is often less wet and finally grades into the wet heath and mire of the valley bottom. In the valley heads, where the seepage step has migrated the least distance from the valley axis, seepage step mires may grade directly to the valley mire below, becoming isolated on the valley side with progress down valley.

    Tuckfield (1973) provides a detailed description of the New Forest Seepage steps.

    Peat Cutting

    Tubbs (1986) indicates that few mire completely escaped peat cutting and which created cuttings separated by causeways parallel to the drainage axis and which today are frequently seen as regular depressions and rectilinear pools.

    Artificial Drainage and its Effects

    Drainage

    Tubbs (1986) explains that there was widespread drainage of many parts of the New Forest, including most of the valley mires, which were drained in the 1920’s. Deep canalised channels were cut along the axes of the mires and spoil heaped on top of the peat beside them. In most cases lateral drains were cut.

    While no mires were completely destroyed by this process, drainage did rupture their hydrological regime and lateral vegetation zonation leading to destruction of plant and animal mire communities. The most disastrous cases were those of mires flanking the Avon Water, which were most extensively drained.

    More recent mire drainage occurred in 1965-85 In order to improve ground for grazing animals and Forestry (Forestry Commission 2001). Thirty-five such schemes were undertaken within eighteen mires. In 1966, a cutting was dredged through the head section of Matley Bog and in 1971-2 axial drains were cut in Dibden Bottom and Bagshot Moor; and in 1968 and 1970 Denny Bog, among the largest of the Forest Mires, was partly drained.

    Hydrological effects of drainage

    At Denny, the main drain grossly modified its hydrology and plant zonation. The axial flushed zone in the upper mire, which was aligned with its outer margin, was destroyed by the new drain which ran down the same side, and here and in the lower mire, the acid outer zones were also lost (Tubbs 1986).

    Drainage at the edge of valley mires (FC 2001) causes:

    • Peat shrinkage by drying and collapse;
    • Loss of surface living Sphagnum layer (acrotelm) leading to enhanced surface flows;
    • Erosion as peat rapidly erodes back on itself; leading to
    • Hydrological disruption affecting water movement and direction.
    Typically water concentrates along flow-lines, which can cause further peat erosion, especially where water is drawn towards a drain causing headward erosion or gross collapse of the mire.

    Loss of the more absorptive surface living layer of peat (the acrotelm), caused by installation of peripheral drains, can lead to increased run-of and rapid erosion.

    These processes simplify mire structure by damaging
    • bog pools;
    • shallow streams; and
    • flushed zones.
    Mire Restoration

    Mire restoration, undertaken by the Forestry Commission for the EU Life Project II, aimed at:
    • reducing excessive water loss and retention of water;
    • maintaining or reinstating high water levels
    • preventing peat subsidence;
    • halting headward erosion; and
    • providing long term conditions for peat growth and a functioning living surface acrotelm layer.
    Restoration was undertaken by soft engineering techniques using heather bales, heathland turf, bank spoil and live brushwood dams.

    Hydrological Mire Types

    Based upon the above discussion and the review of individual mires below, the mires can occur in a wide range of hydrological and hydrogeological conditions. Most mires contain combinations of several of these types and in detail, the hydrology and hydrogeology is always complex because of lithological variation in geological substrates and the presence of heterogeneous Head deposits.

    Type 1 Groundwater fed valley bottom mires

    The simplest situation, developed in wholly permeable substrates with permanent groundwater saturation in valley bottom.

    Type 2 Seepage fed valley side mires

    Developed in permeable substrates on valley sides where groundwater levels are high.

    Type 3 Spring fed valley side mires

    Developed where springs and seepages occur at the exposed junction of more permeable strata over less permeable strata.

    Type 4 Multiple spring fed valley side mires

    Where strata of differing permeability occur at different depths.

    Type 5 Seepage step mires

    Where rapidly permeable strata overlie slowly permeable strata at gravel terrace edges.

    Type 6 Surface water mires on slowly permeable strata

    Where there is a wide slowly permeable catchment of clayey or heavy clay loam materials causing rainwater to flow over the land surface and mires to develop in topographic low-ways. Heterogeneous Head deposits are very common in low-ways in this situation.

    Type 7 Complex mires

    Developed often in broad basins in areas of complex geology and combining at least several of the previous mire types. Water chemistry and mire types are usually very variable.

    8.0 EXAMPLE MIRE SYSTEMS

    8.1 ACRES DOWN

    8.1.1 Description

    The 1:25000 scale Ordnance Survey map shows that the valley bottom to the southeast of Acres Down (SU275086) is a linear feature at the head of a tributary of the Highland Water. The uppermost two headwater streams arise off Pilmore Gate Heath to the north and the valley is between high points at Acres Down to the northwest and Broom Hill to the southeast.

    Brewis et. al. (1996) consider Acres Down to be a calcareous marl bog on the most northerly occurrence of the Headon Beds outcropping at the top of a slope below plateau gravels.

    The 1:50000 scale British Geological Survey Sheet 315 shows that both highpoints, including Pilmore Gate Heath, occur on outliers of Becton Sand capped by small areas of Headon Beds and topped by small patches of Older River Terrace deposits. The lower intervening area, including the valley sides is part of the large outcrop of Chama Sand. The geological map shows a thin strip of alluvium on the valley floor. It is very likely that the lower valley sides are covered with thin heterogeneous Head deposits and on which the vegetation will be established. There is no evidence of substantial peat deposits on the map, although peat may be included within the alluvial area and smaller areas in seepage zones on the valley sides.

    8.1.2 Hydrological Conceptual Model

    On the basis of the geological map, it is likely that the valley bottom is largely fed by groundwater flow within a catchment underlain by Becton and Chama Sands. The groundwater table intercepts the lower valley sides and valley bottom and appears in a minor valley bottom stream. On the basis of the geology it would be expected that the waters are most likely to be strongly acidic, with a small contribution from the more base-rich Headon Beds.

    Brewis et. al. (1996) compare Acres Down to other mires affected by calcareous water and so it may be that there is stronger influence from the Headon Beds than can be inferred from the geological map. The vegetation is likely to be established on Head deposits overlying the Tertiary strata and which will be controlling the detailed distribution of different hydrological conditions. The nature of the Head deposits is unknown and they may be less permeable than the deeper substrate and could contribute a degree of drainage impedence to the rooting zone of the vegetation.

    8.2 BOUNDWAY HILL

    8.2.1 Description
    The 1:25000 scale Ordnance Survey map indicates a small valley and drain north of Boundary Hill (SZ262987) and forming a small tributary of the Avon Water in the southeast of the Forest.

    The 1974 1:50000 scale British Geological Survey sheet 330 and the 1:25000 scale Sand and Gravel Assessment map indicate that the valley arises off the edge of Plateau Gravel (River Terrace Deposits) and flows northeast, first over the fossiliferous clays, silts and sands of the Headon Beds and then down on to the Barton Sands before joining a narrow strip of alluvium along the Avon Water floor. The Mineral Assessment map indicates that the valley floor is underlain by gravels.

    In reality it is likely that the valley side is covered with flinty loamy, or even clayey, Head derived from the upslope deposits and on which wetland plant communities will be developed. The Barton Sand has more recently been divided into the upper fine sandy Becton Sand and the lower clayey silty sands of the Chama Sand and this interpretation may better reflect the way in which water behaves on the site.

    Brewis et.al. (1996) consider Boundway Hill to be an extensive calcareous mire grading above into more acid-flushes, fed from plateau-gravels.

    8.2.2 Hydrological Conceptual Model

    The main catchment is a wide area of rapidly permeable terrace gravels to the south. Groundwater in the gravels is likely to be perched over the more slowly permeable Headon Beds and would be expected to appear at springs and seepages where the junction of the gravels and clay is intercepted by the valley side. Water off the junction is likely to flow over or through heterogeneous Head deposits thinly covering the calcareous clays, silts and sands of the Headon Beds and also the downslope more permeable Barton Sands where surface water may join groundwater.

    Headward springs off the gravels may be acidic, although it is likely that water flows in the stream are base enriched as they flow over any Head derived from the Headon Beds (as indicated by Brewis et.al 1996). The mire communities are likely to be developed on heterogeneous Head deposits that will define the water regime at any one location possibly providing a mosaic of surface and groundwater conditions.

    8.3 BRAMSHAW WOOD

    8.3.1 General Description

    Bramshaw Wood (SU261169), to the southwest of Nomansland in the very north of the Forest, contains a small northeast trending valley. British Geological Survey Sheet 315 shows that the catchment to the southwest is underlain by silty sands, sandy silts and sandy clays of the Selsey Sand (the upper part of the Bracklesham Group). The stream soon flows over the underlying laminated clays and sands of the Marsh Farm Formation. The valley bottom is shown as a narrow strip of undifferentiated river terrace gravels. It is likely that valley footslopes are covered in heterogeneous Head deposits.

    8.3.2 Hydrological Conceptual Model

    The main catchment is a wide area of relatively permeable Selsey Sand. Water in the sands is likely to be perched over the less permeable Marsh Farm Formation and is likely to appear at springs where the junction of the permeable and less permeable deposits is intercepted by the valley side. Water off the junction flows over the Marsh Farm Formation to the valley floor. Headward springs may thus be acidic, although it is likely that water flowing in the stream is slightly base-enriched as it flows over the Marsh Farm Formation. Head deposits may control the distribution of local water regimes and peat deposits.

    8.4 BUCKHERD BOTTOM

    8.4.1 General description

    The mire (SU208085) is at the head of a tributary stream of the Linford Brook, itself a tributary of the River Avon.

    Newbould (1960) describes this mire as:
    • On Barton Sand and Clay with some drainage from Plateau Gravel;
    • A narrow, relatively steep valley with a well defined central stream; and
    • With both flushed and Sphagnum-rich vegetation (better developed at the head of the valley).
    FC (2002) describe this as a valley mire system on steep to fairly steep gradients that has suffered loss of mire habitat along lower stretches adjoining forestry enclosures. Nine dipwells were installed for the mire restoration project at points along the mire within a mosaic of wet heath and acid grassland and in valley mire.

    Restoration work to stop headward erosion along a badly eroded channel was completed in June 2000.

    8.4.2 Geology

    The British Geological Survey sheet 314 shows Buckherd Bottom as having a catchment to the east on Plateau Gravel (Older Terrace Deposits). Immediately west of the gravel outcrop is a narrow outcrop of the underlying Barton Sands with Buckherd Bottom being developed primarily on the Barton Clay. This map shows an older interpretation of the Barton Sands and which is now divided into a more permeable upper layer, the Becton Sand, and a slightly less permeable lower layer, the Chama Sand. The precise relations of these deposits are not known at Buckherd Bottom although from the stratigraphic relations shown on the map, it is likely that the lower Chama Sand occurs here. All of these Tertiary deposits are likely to be overlain by heterogeneous Head deposits derived from materials upslope.

    8.4.3 Peat and soils

    Three auger borings were made in Buckherd Bottom in March 1999 at locations recorded by the Forestry Commission close to previously installed dipwells. None of these revealed any peat, the profiles being on heterogeneous loamy Head deposits.

    Two of the borings, into grazed grassland with Calluna and Myrica, revealed typical stagnogley soils with seasonally waterlogged clay loam, silty clay loam and silty clay layers over gravelly material at between 55 and 85cm depth. The third bore into an area of dense Molinia, Myrica, Erica and Sphagnum community revealed permanently waterlogged stagnohumic gley soils with an upper 20cm depth of humose silty clay loam over silty clay and silty clay loam with peaty lenses over gravel 75cm.

    8.4.4 Hydrological conceptual model

    The Older River Terrace deposits tend to be permeable only in their upper layers and have only a slow hydraulic conductivity in their less permeable lower horizons and so comprise only a minor aquifer giving rise to very small flows only. The underlying Barton Sands (Chama Sand) aquifer is the more likely source of water and which here will provide shallow groundwater perched over the slowly permeable Barton Clay.

    Water will be issuing from springs and seepages where the valley side intersects to the Chama Sand-Barton Clay junction. Water off these springs will be held in loamy and sandy Head deposits above the clay giving rise to poorly drained land affected by permanent surface waterlogging on which the peat deposits (if any) will be developed.

    The absence of peat in the auger borings suggests that either organic materials were never deposited in that area, or that peat has been lost to drainage operations.

    8.5 CLAYHILL BOTTOM

    8.5.1 General description and geology

    Clayhill Bottom (SU234017) and Scrape Bottom combine to form a small south-flowing tributary valley of the Avon Water in the southeast of the Forest.

    The 1974 British Geological Survey sheet 330 shows that the Clayhill Bottom valley is deeply re-entrant into Plateau Gravel (River Terrace Deposits) and developed on the underlying Barton Sands. More recent interpretations of the Barton Sand divides them into an upper fine-sandy Becton Sand and a lower clayey silty sandy Chama Sand. Alluvium is shown on the valley bottom and the 1:25000 scale Mineral Assessment Map shows the alluvium as underlain by gravels. It is very likely that the valley side footslopes are covered by heterogeneous Head deposits derived from the upslope deposits and which will be obscuring the Tertiary deposits.

    8.5.2 Hydrological conceptual model

    It is likely that water supporting the mire arises in small part from the permeable strata in the River Terrace Deposits catchment and in greater part from groundwater in the Barton Sands (itself fed by percolation through the terrace deposits). This means that the water is likely to be wholly acidic and nutrient-poor. The precise disposition of different water regimes and peat deposits is likely to be controlled by local topography and the characteristics of any Head deposits that may be present.

    8.6 CRANESMOOR

    8.6.1 General description and geology

    Cranesmoor (SU 195029) is part of a large and complex valley mire system in the west of the Forest draining ultimately to the River Avon. The area of Cranesmoor has been extensively studied in the past although no modern interpretation of the waterflows and peat deposits in relation to geology and the wider catchment appears to have been undertaken.

    This large complex topographic area (which includes Cranesmoor, Strodgemoor and Bagnum Bog) takes seepage and groundwater from the surroundings and passes the water to a valley bottom stream system arising in the north and flowing out of the area to the southwest. The topography is complex with minor ridges separating water flows arising from different directions and different geological deposits.

    8.6.2 Geology
    The 1991 British Geological Survey 1: 50 000 scale sheet 329 provides an updated geological map of the area. NB. This more recent map provides considerably more detail and a different interpretation of the deposits to that shown on the 1976 edition that would have been used during earlier studies of the site.

    The 1991 geological map shows that:

    • the wetland area sits within a shallow valley system developed on the gentle west facing slopes east of the north-south Burley ridge;
    • the Burley ridge and adjoining slopes are underlain by the shelly clays, silts and fine-grained sands of the Headon Beds;
    • lower land to the west successively exposes in sequence, the underlying Becton Sand, Chama Sand (both variously called the Bagshot or Barton Sands in the past) and then the Barton Clay;
    • the Tertiary deposits are overlain and obscured within the valley system low-ways by Head and on which the peat deposits appear to occur;
    • valley floors winding through the area are shown as containing narrow strips of alluvium; and
    • terrace deposits are sparse in the vicinity with a small area shown on the northern part of Burley Ridge at Burley Hill to the northeast of Cranesmoor, and very small area shown immediately to the south of the Moor.
    8.6.3 Literature sources and hydrological interpretation

    Earlier accounts use what is now older geological mapping to interpret the hydrology.

    Brewis et.al (1996) indicate that this mire is on deep peat that developed a raised bog between two diverging base-rich flushes. Peat digging has removed surface peat layers.

    Tubbs (1986) explains that Cranesmoor occurs within undulating heathland on Bagshot Beds with valley mires filling broad hollows in the drainage network.

    Burton and Hodgson (1987) explain that this 95ha mire is developed over Barton Sands with peat 4-5m thick in the east and quotes Newbould (1960) in separating two categories of surface peat: 1. peat in the central area with ash content less than 20% with oligotrophic vegetation and 2. flushed peat along main zones of water movement with ash contents of 20-50% with mesotrophic vegetation.

    Barber and Clarke (1987) summarise earlier work and explain that Cranesmoor has been the site of extensive investigations in the 1950’s by Newbould (1960) and by Segrief (1960) who respectively described the present vegetation and the water chemistry, and its paleoecology. Cranesmoor, one mile west of Burley, is by far the largest mire complex in the New Forest and is rather untypical. It is situated in the far west of the Forest (SU 193028) below the Burley Ridge which is capped by Headon Beds. The mire is both surrounded and underlain by Barton Sand (now, 1996, divided into the Becton and Chama Sands), which is heavily podzolised. Unlike most mire systems there are no alder carrs and from the top of the Burley Ridge the view over Cranesmoor is an excellent analogue for the Boreal Period of the early Holocene.

    Seagrief (1960) indicates that the bog occurs in a wide valley excavated in the preceding full-glacial or late glacial time and filled by organic deposits accumulated rapidly during the Pre-boreal and Boreal periods. Depressions on the eastern side of Cranesmoor also contained the deepest peat.

    It is emphasized that the whole of the Cranesmoor complex shows signs of extensive peat cutting giving rise to steep sided rectilinear pools separated by causeways

    The bog is in three parts:
    • Sphagnum Bog, a slightly ridged central area (possibly a raised mire) shielded from water flow by two ridges of Barton Sand and which remained oligotrophic through the Holocene and had almost entirely Sphagnum remains;
    • Flush Bog, a large flushed area on the south side and older than the other two showing an accumulation of clayey monocotyledonous fen type peat before developing Sphagnum cover in late Boreal-early Atlantic times and receives the major portion of drainage water from the Burley Ridge; and
    • Little Bog, a small flushed area to the north and which accumulated monocotyledous fen type peat at a rapid rate through the Boreal before developing into a Sphagnum mire in late Boreal-early Atlantic times.
    Newbould (1960) in his classic paper, describes Cranesmoor in some detail and discusses that:
    • Lies in a wide flat basin within Barton Sand with two marginal, poorly defined streams and with some drainage from wooded Headon Beds;
    • Burley Ridge to the east has a capping of Headon Beds clay and Plateau Gravel.
    • Lower land to the west in Kingston Great Common has Barton Clay extending as a tongue to the outfall of Cranesmoor;
    • Recent disturbance has included turf digging and making of decoy pools for duck, army manoeuvres and creation of a causeway crossing the bog;
    • General slope is to the northwest and the bog includes two sandy knolls, and prominent ridge extending into the bog from the south;
    • Outflow streams join and leave the bog at its NW corner;
    • The presence of several plant species are indicative of former lake conditions;
    • Well-defined flushed vegetation along marginal areas, and very well developed Sphagnum-rich vegetation in a shielded area between two streams.
    Examination of the upper 10-20cm of soil surface distinguished three conditions:

    • Mineral soils with wet heath, strongly oxidized in summer and pH<4.5 and base saturation <35%;
    • Peat soils with a loss on ignition of >80% and base saturation <52%;
    • Flushed peats with a loss on ignition of 50-80% of dry weight, higher pH values and base saturation >52%.
    The bog was identified as having a slightly more acid and dilute central area and a more heavily flushed area on either side and that water pH discriminated most effectively between the main plant groups on Cranesmoor. Two flushed areas were distinguished with pH values above 5.0. It was thus possible to identify flows of base-rich water arising off the Headon Beds on the Burley Ridge to the east. More acidic flows were also identified. The total outflow from the bog is canalised into two small streams which join and flow to the northwest.

    It was considered that even if nutrient levels were low in the flushed area, constant replenishment would lead to the flushed effect and which did not occur in areas shielded from such flows.

    8.7 DENNEY BOG WEST

    8.7.1 General description

    Denny Bog is a complex area of wet low-ways divided into a western complex and an eastern complex by a railway line. The hydrological and landform relationships are not clear from the 1:25000 scale OS map, nor from the 1:50 000 scale geological map. The mire system is divided into that part west of the railway line and that part to the east of the railway line. The entire bog area is surrounded by the Bishop’s Dyke linear earthwork.

    Western Denny Bog (centered approximately on SU344053) drains westwards (via a drain on the southern side) towards the railway line and is broadly contained within the area enclosed by a low bank known as the Bishop’s Dyke.

    Newbould (1960) describes Denny Bog West (SU343053) as:
    • On Barton Sand, some drainage from wooded Headon Beds;
    • A wide flat basin with a poorly defined central stream, becoming canalized lower;
    • Widespread flushed vegetation and very well developed Sphagnum-rich marginal areas in upper part of bog.
    Tubbs (1986) explains that the central flows of Denny Bog West (SU347053), which receive water from the Headon Beds and Barton Clay, are about neutral in reaction.

    8.7.2 Geology and hydrology

    The most recent edition (1987) of the British Geological Survey 1:50 000 scale Southampton Sheet 315 suggests that the higher land immediately west of the bog (and which also surrounds westernmost part of the Bog as a horseshoe shaped area open to the east) has shelly clays and silts, and sands, of the Headon Formation underlain by Becton Sand. The Becton Sand crops out on the slopes to the east and within the horseshoe shaped area and on which Denny Bog west is developed. It is likely that the solid deposits are overlain by heterogeneous Head.

    A single auger boring was made in Woodfidley passage in the southeast of the mire area and this revealed a permanently waterlogged coarse loamy over fine silty mineral material to 118cm depth. The profile had a very thin humose surface horizon and met the criteria for a typical cambic gley soil in loamy material passing to flinty Head. This indicates that the mire materials here had non-peaty permeable mineral upper layers over less permeable flinty silty clay loams at depth.

    It is very likely that the stream source from the west and seepages and surface flows from the west, south and northwest are enriched with calcium off the Headon Formation strata and would raise the pH and base status of the Mire. Surface and seepage sources from the northeast would be primarily off the Becton Sand (locally capped by terrace deposits) and so would tend to be more acidic and base-poor. The presence of Head deposits in the low-ways is very likely and would influence the detailed hydrological system in the rooting zone of the vegetation.

    8.8 DENNEY BOG EAST

    8.8.1 General description

    This part of Denney Bog (SU 354048) was visited to assist with developing the scheme of restoration, following which a report was prepared for the Forestry Commission on aspects of the mire and its restoration (Allen 1998). Beaulieu is about 4km to the southwest and the Forestry Commission picnic site at Pig Bush is about 750m to the east-northeast. Drawing at the end of this section shows the general relationships.

    Bishop’s Dyke in Denny Lodge Parish encloses an area of Denny Bog and adjacent heathland known as the Bishop of Winchester’s Purlieu. The mire system is divided by the Brockenhurst railway line and the area described here is to the east of the railway.

    The mire is a complex of communities with wetter and drier and more acidic and less acidic plant associations.

    The area examined was that partly drained part of the mire extending about 0.5km along an eroding drain north-northwest of a footbridge (now rebuilt). Stephill Bottom is to the north.

    This part of the mire supported mainly M21 Narthecium ossifragum - Sphagnum papillosum valley mire with Sphagna, Eriophorum, Narthecium and Drocera. Lateral soakways (draining into a central stream) containing M29 Hypericum elodes and Potamogeton polygonifolius. The northernmost part of the mire beyond the drain head was a wide and very wet area of M29 soakway community feeding water by surface and subsurface flow southwards towards the open drain. The streamside soakways were thought to have developed following cutting of the drain and were taking water off the mire directly to the drain. Gently sloping land to the southwest of the valley mire supported M16 Erica tetralix – Sphagnum compactum wet heath and land to the northeast had willow carr.

    Part of the mire, upstream of the bridge, has been affected by the drainage works. Headward erosion has occurred for some 30-40m creating a flowing stream fed by a series of mire soakways with resultant de-watering of the mire. The part of the bog affected by headward erosion is about 500m east of the railway line and crossed by a well-used path via a series of bridges linked by a boarded causeway.

    The drain and soakways part of the mire has now been partly restored by infilling with bales of cut heather.

    The general character of the mire upstream of the footbridge system is illustrated in the appended drawings 1 and 2. This is an area of relatively undisturbed mire and wet woodland (carr), but downstream of the bridge, a drain has been cut to take mire drainage water to the canalised head of the Shepton Water, itself a tributary of the Beaulieu River.

    8.8.2 Drainage and restoration

    Forestry Commission (2002) indicate that this very large mire was drained in the last 35 years causing severe ecological damage to parts of the bog. Fourteen dipwells were installed for the mire restoration project and monitored from February 1999 to November 2000.

    Restoration work was completed in September 1998 using heather bales to prevent headward erosion. The larger part of a large peripheral drain was blocked using heather bales, spoil and heather turves and a bridge crossing constructed to aid restoration. A considerable amount of water still left the mire. Dipwell results suggested that water levels in the valley had been raised.

    8.8.3 Landform

    The mire is at about 15m OD and bounded by open forest, mainly wet heath passing to humid heath on adjacent slopes. Furzy Brow forms higher land to the northeast and Penny Moor is to the south.

    The mire surface is relatively level but interrupted by lower ways generating small streams and hence the bridged footpath.

    8.8.4 Geology, soil and peat deposits

    Sheet 315, the Southampton Sheet of the British Geological Survey, shows the mire to be underlain by alluvium which in turn is underlain and bounded by Becton Sand being the uppermost member of the Barton Group. Away from the valley, higher land is either underlain by the Headon Formation (in the south and west) or gravel terrace deposits (in the north).

    Some of the upstream water source appears to be on the Headon Beds to the west. Parts of the Barton and Headon Groups are shelly and this may explain the higher water pH values found in drains and streams arising off the mires.

    Forestry Commision (2002) report that the valley floor has thin peat (generally between 0.5 and 0.7 thick) over slightly flinty loams and which are likely to be Head deposits. The alluvium shown on the geological maps appears to be a mixture of loamy Head and Peat. Peat bores made on site showed peat depths of generally less than 25cm depth over mineral material.

    8.8.5 The mire and stream

    The mire as a whole (upstream of the bridge) appears to be relatively level and with only small streamlets developing and some areas of very wet saturated land. It is understood that in winter much of the mire is far wetter. The surface is tussocky, but at the time of the visit some of these had lost their intervening water pools.

    About 45m upstream of the bridge, the watercourse originates as a somewhat meandering small narrow streamlet fed by flows off the very wet Hypericum rich bog either side. Small flows off the bog join the stream and after about 15m the course is about 1.7m wide and by about 35m the stream is some 2.5m wide and has become incised to about 0.75m depth. This part of the stream is partly overhung by heather bushes.

    At this point the whole stream opens out to form a pool about 5.5m wide and this is bridged at a distance of some 45m from the source. The pool has 1m high vertical faces to the south exposing the slightly flinty clayey and loamy substrate. The northern and more sheltered side, slopes more gently down to the pool in a series of shallow well vegetated steps down which flow several interweaving soakways. There has been some slumping of the bank here into the stream.

    It is likely that downstream flow of water across the mire surface is substantially prevented by the causeway (other than that passing to the drain) and this may have been allowing the immediately adjoining mire to remain wetter and for longer.

    8.8.6 Peat deposits and soils

    The mire substrate was examined in three transects, a northern transect in the upper part of the mire, a central transect just north of the causewayed footbridge bridge, and a southern transect near Rowborough Pond about 200m southeast of the bridge. The locations of the bores were mapped by the Forestry Commission. Of 11 recorded hand augered boreholes, ten had peat depths of only up to 22cm and only one had peat greater than 22cm depth and that profile had mostly fluid organic material rather than peat.
    The northern transect had four borings, only one of which showed the presence of peat. The peat profile had 20cm of loamy humified peat over very fluid material to 80cm depth and assumed to be very fluid suspended peaty material over fine loamy sand. The other three borings had typical humic gley soils with a maximum of 22cm of humose or peaty material over loamy or sandy flinty head or stoneless Tertiary deposits.

    The central transect had three bores to about 1m depth, all in typical humic gley soils. All had waterlogged loamy mineral material with very thin surface peaty layers to 12cm depth developed in thin loamy head over stoneless Tertiary sandy silt loam and fine sandy clay.

    The three borings in the southernmost transect made by auger to 1.2-1.5m depth showed an almost complete absence of peat and having had mineral sequences variously of sandy loam, sandy silt loam and sandy clay loam with thin humose or peaty topsoils to no more than 18cm depth. Thin layers of peaty material occurred within this sequence. The profiles met the criteria for typical humic-gley soils in permanently waterlogged silty or loamy material over flinty Head and with very thin peaty topsoils.

    8.8.7 Hydrological conceptual model

    It seems likely the water table in the Becton Sands is near to the surface and supplies water direct to the waterlogged mire substrate from bed flow. Some water will arise from rainfall and some from springs and seepages on adjacent slopes. A substantial flow appears to arise from the undrained mire to the north where surface water running off the very wet northern part of the mire, between tussocks, was seen feeding the upper part of the watercourse directly. The influence of groundwater off the Headon Formation to the west is indicated by the higher pH values detected of about 6.5. Surface pools in adjacent parts of the mire had lower pH values of 4-5 and these probably reflect the acidifying characteristics of Sphagnum bog-mosses occurring here.

    The digging of an artificial drain along the edge of the mire downstream of the bridge has not only drained the adjacent land, but also caused headward erosion of a 30-40m channel into the mire upstream of the bridge. Numerous small streams (or mire soakways) drain into this channel effectively taking water from the surface of the bog. The upstream channel is typically 2m wide and varies in water depth from a few centimetres in the north to midway pools almost 1m deep and possibly related to erosive nick points. At the time of the visit, the causewayed footbridge was probably holding back some water in the mire. The footbridge has since been rebuilt.

    Peat deposits are very thin, generally less than 25cm thick over mineral material in Head and Tertiary deposits. If peat had at one time occurred, it appears to have been lost, perhaps by the effects of the land drainage. Alternatively, the mire may always have been developed over waterlogged mineral substrates.

    8.9 SHATTERFORD BOG

    8.9.1 General Description

    Forestry Commission (2002) indicate that this mire (SU345062) within the Beaulieu River catchment, is considered a stable system, and although probably drained in the last 35 years, it is thought to be buffered by the worst excesses of drainage.

    The mire occurs in an elongate basin in the open forest to the west of Beaulieu Road Station and is crossed at the lower end by the Brockenhurst railway line. Stephill Bottom is east of the railway line and from where the drainage water appears to pass partly south into Denny Bog and partly east to the Bealieu River.

    The 1:50000 scale geological map Sheet 315 shows the mire as underlain by a broad area of alluvium within a large area of well-sorted fine-grained sand of the Becton Sand. A small tributary valley feeding into the southwest corner of the mire appears to drain the calcareous Headon Formation. Much of the catchment is thus fairly permeable and likely to be acidic with the possibility of less acidic flows arising from one direction.

    Two auger borings were made in March 2002 and revealed raw oligo-amorphous peat soils with peat depths of 65 and 87cm over gravels. Uppermost layers had raw Sphagnum peat, below which was a fluid layer of watery humified peat over loamy peat or humose clay loam.

    8.9.2 Hydrological conceptual model

    The mire is set within a broad basin having a large catchment of podzolised permeable sandy strata with a possible small component from the Headon Beds. Most water in the mire is thus likely to be strongly acidic and the permeability of the catchment suggests that considerable water would flow into the mire. This is demonstrated by the fluid nature of the sediments within the mire.

    8.10 DIBDEN BOTTOM

    8.10.1 General description

    Dibden Bottom is a large complex area of low lying ground (SU 393066) drained by two small streams in the smaller eastern catchment of the Beaulieu River to the south of Applemore village and northwest of the urban area of Dibden Purlieu in the east of the Forest.

    Forestry Commission (2002) explain that the mire supports intact and damaged mire and wet heath, drained throughout the last 30-50 years. Twenty-one dipwells were installed in transects on wet heath, valley mire and willow carr. Seventeen of these were monitored from March 1999 to November 2000.

    The 1:50000 scale geological map Sheet 315 shows the land here to consist of a dissected part of a low-level river terrace deposits that overlie clayey silty sands of the Chama Sand and with valley bottoms containing alluvium. The Chama Sand has an irregular outcrop between and around the stream systems.

    The permeable gravel terrace deposits are likely to have a high hydraulic conductivity compared with the underlying Chama silty sands likely to have a moderately slow hydraulic conductivity. This means that springs and seepages are likely to occur at the junction of the two deposits and that the water in mires is likely to be retained for a time above the substrate.

    Six auger borings were made in March 1999 and all of these revealed humic gley soils with peat depths of only between 8cm and 26cm over clay loam or sandy loam over gravels below between 28 to 80cm depth.

    Dibden Bottom was restored in two phases completed in December 1999 and January 2001 respectively. Phase 1 blocked peripheral drains around the valley mire and half the drains on wet heath, despite which a considerable amount of water was leaving the mire along an over-deepened channel. Phase 2 blocked the outflowing channel. Provisional results (FC 2001) indicated that water levels have been raised.

    FC (2002) lists the dominant wetland plant communities in the restoration area as:

    Wet Heath M16 Erica tetralix-Sphagnum compactum wet heath
    M16a, typical community and M16c Rhynchospora alba-Drosera intermedia subcommunity

    Valley Mire M21 Narthecium ossifragum-Sphagnum papillosum valley mire
    M21a, Sphagnum auriculatum-Rhynchospora alba subcommunity
    M29 Hypericum elodes-Potamogeton polygonifolius soakway

    Woodland W4 Betula pubescens-Molinia caerulea woodland.

    8.10.2 Hydrological conceptual model

    There is very little evidence on which to base a model other than that set out above. It is likely that the mire water is sourced mostly from areas of permeable terrace deposits and enters the mire from a series of springs or seepages at the junction of the gravels with the underlying more slowly permeable Tertiary silty sands. Auger borings suggest that there is very little peat and that this is underlain by varied loamy Head deposits. Water from off the mire outfalls in a small number of streams to join the Beaulieu River to the west.

    8.11 FORT BOG

    8.11.1 Setting and Geology

    There appears to be very little information on this mire. From the grid reference provided, (SU335084), the mire appears to be located alongside the Beaulieu River to the north of Matley Wood.

    The 1:50000 scale geological map Sheet 315 shows the river to be bordered by a narrow strip of alluvium passing across the outcrop of the Chama Sand. The overlying Becton Sand occurs on higher ground away from the river.

    8.11.2 Hydrological conceptual model

    On the basis of the geological map, the mire may either be on the alluvial strip in which case it could be a floodplain mire, or it may be on the valley footslopes. If on the valley footslopes, the mire water is likely to be sourced from the more permeable fine-grained sands of the Becton Sand aquifer and emerge as springs and seepages at the junction with the overlying less permeable clayey silty sands of the Chama Sands. Head deposits are likely to overlie the Tertiary deposits. The mire would then be formed on the saturated Head deposits over the less permeable Chama Sands and discharge to the Beaulieu River.

    8.12 HIVE GARN BOTTOM

    8.12.1 Introduction

    Hive Garn Bottom (SU197150), a typical valley mire in the northwest of the New Forest near Godshill, was the subject of a detailed study in 1985 by Mike Clarke and Ron Allen, then at Southampton University and with the Soil Survey of England and Wales respectively. A summary of the study is published in Clarke M J and Allen R H 1986. Peatland soil-plant relations in the New Forest. Aquat.Bot 25: 167-177 and from which this description has been derived. Results of the detailed substrate studies undertaken of this mire remain unpublished.

    8.12.2 Site Characteristics

    This small, steep-sided valley is cut into a high level terrace at 105m AOD. The flinty loamy terrace deposits (now known as Older River Gravels) are thin and the soils incorporate clayey substrata on which is developed humid heath. Water seeping through this heterogeneous but permeable drift flushes out just below the terrace edge and a mire has developed on the seepage step. Downslope, further wet heathland communities occur on soils in thin drift and there is another mire in the valley bottom.

    8.12.3 Soil Characteristics

    Statistical studies of the vegetation and soil water regimes distinguished the two mires together with dry, humid and wet heath in the adjacent and intervening areas and demonstrated a wetness gradient between them. Studies of the water retention characteristics of the soils in the terrace and upper valley side slope showed that the upper layers were more permeable than those below. Compact subsurface horizons also occurred on the seepage step soils. These slowly permeable soil layers act as a barrier to downward movement of soil water.

    8.12.4 Soil Water Regimes and Plant Communities

    Podzolic soils on the terrace margin had slowly permeable subsoils creating temporary seasonal waterlogging in the upper layers. Soils on the seepage step had peaty surface layers and gleyed mineral subsoils and were waterlogged for prolonged periods. Soils on the irregular slopes below the seepage step were weakly podzolised and gleyed at depth indicating prolonged winter waterlogging by laterally flowing water. The deeper peat soils in the valley bottom are underlain by intensely bluish, and often fluid, gleyed horizons suggesting that these deposits have remained waterlogged since the materials composing them were deposited.

    The study showed that the distribution of plant species in valley mire and wet heath is closely correlated with soil water table fluctuation within the soil and complicated by lateral movement within the water column. Seasonal fluctuations in soil waterlogging in the seepage step (with thin humified peaty layers) and prolonged waterlogging in the valley bottom mire (with deeper less humified peat over unripened substrates) may influence the vegetation pattern. The differences in plant community composition seem to be related in part to differences in the exposure of peat to aerobic conditions, and the degree of humification.

    8.12.5 Soil water regime model

    The soil water regime model (see figure above) developed at Hive Garn Bottom is applicable to other high terrace areas in the New Forest. The surrounding gravel capped ridges provide a catchment in which water movers vertically and laterally through permeable soil horizons in drift deposits or laterally through permeable underlying Tertiary strata. Movement of water into the soils on the seepage step occurs mainly just below the ground surface, and so the soil water regime depends on the seasonal supply of water from the immediate plateau catchment. Water movement downslope of the seepage zone depends on the surface slope, the thickness of the permeable soil horizons and irregularities in the depth to slowly permeable horizons. The valley bottom mire, being in a low-lying situation, receives water from a wide catchment and so remains permanently waterlogged.

    8.13 REDHILL BOG

    8.13.1 General description

    Redhill Bog (SU 268019) in Rhinefield Parish is in the open Forest and, together with the adjacent Holmhill Bog, provides a tributary source of water to the Silver Stream and which flows into the Ober Water, itself a tributary of the Lymington River which enters the Solent at the coastal town of Lymington. The drawing the end of this section taken from the restoration plan shows the general relationships.

    The lower part of Redhill Bog has been drained by a central excavated drain which appears to take water from a high quality valley mire habitat at the head of the valley. The mire is thought to be drier than in the past.

    Redhill Bog has suffered headward erosion following drainage (FC 2002). Ten dipwells were installed during the mire restoration project, six in the valley mire and four in an area of degraded mire and wet heath. These were monitored from March 1999 to October 2000. Restoration work completed in August 2000 involved filling drainage channels and erosion points and this has resulted in high water levels.

    The mire was examined by Ron Allen in February 1998 (Allen 1998) and found to comprise:

    • A valley floor mire drained by a central artificial watercourse;
    • A lower valley side seepage mire; and
    • Small areas of step mire and spring fed soakways arising from below a bank.
    The precise geology of the area within and around the bog is uncertain in the absence of detailed survey or more modern geological mapping.

    8.13.2 Landform

    The main part of Redhill Bog is located within a relatively narrow north-south trending valley arising from land known as Hinchelsea Moor cut into the north side of an easterly extension of the Wilverley Gravel Plateau about 6km southwest of the town of Lyndhurst and 3km west of Brockenhurst.

    The head of the peat filled valley is at about 40m AOD and the lowermost point of the study area at the junction with the head of the Silver Stream (taken as at the footbridge) is about 30m AOD giving a total fall of about 10m over a distance of about 850m.

    Only the northern 160m of the valley (south of the footbridge) is directly affected by drainage, although there are likely to be less easily detectable effects further upstream to the south. The lower part of the valley described here comprises a more level area in the bottom of the valley bounded by gently sloping sides in which are set small areas of more level ‘step’ mire. The upper edges of the mire are bounded by short steep banks below which areas of strong seepage and linear soakways were found.

    8.13.3 Geology

    The Redhill valley is entirely cut into Barton Sands (now divided into the upper fine-grained sands of the Becton Sand and the lower clayey silty sands of the Chama Sand) described by the Institute of Geological Sciences (MAR 122 1982) as pale yellow fine quartz sands. The upper source of Redhill Bog in Hinchelsea Moor is cut into a narrow irregular plateau developed in flinty river terrace deposits (Plateau Gravels).

    While Barton Clay underlies the Barton Sands, this appears at this location to be at some depth with the nearest outcrop some 2km to the west at the head of the Ober Water.

    Stratigraphy Quaternary Peat on valley floor
    Flinty Head infilling valley floor
    River Terrace (Plateau) Gravels at head of valley
    Tertiary Barton Sands (Becton Sand over Chama Sand)
    Barton Clay (at depth only)

    The valley floor has thin peat over gravelly Head.

    8.13.4 Peat Deposits

    Six auger borings were made in two transects across the mire 35m and 135m upstream from a bridge. Each transect had a bore in the adjacent wet heath, in the gentle slope forming the outer zone of the mire, and within the main mire close to the drain.

    A wet heath zone had humic gley soils with 3cm of Sphagnum over humified loamy peat with sandy inclusions or humose silty clay loam to 35-37cm depth. Below this were fine loamy sandy and fine sandy silt loam layers to 90cm depth in one bore and gravels in the other.

    The outer edge of the mire had between 32 and 48cm of Sphagnum peat over humified loamy peat to at depths of between at least 90cm 32cm depth over silty clay loam in the other bore.

    The two central mire bores had 72cm of very fluid watery Sphagnum peat over gravels.

    8.13.5 Hydrology

    The semi-natural state

    Based upon older geological mapping, it would appear that the Terrace Gravels provide a wide permeable aquifer through which rain water percolates into the Barton Sands to form groundwater held within the sands over the Barton Clay at depth. This groundwater cannot descend through the deeply underlying Barton Clay and so remains ‘perched’ above it.

    Given the more modern interpretation of the sandy Tertiary strata it is more likely that water from the river terrace deposits passes down into the permeable Chama Sand to be perched over the less permeable clayey silty sands of the underlying Becton Sand.

    This means that groundwater has to flow laterally through the Chama Sand where it emerges in valleys around the plateau edge at the junction of the Chama Sand and the Becton Sand. In this instance, water flows slowly through the Chama Sands to emerge as seepages at Hincheslea Moor and the sides of the Redhill Bog valley. It is also likely that the pressure difference between the top and bottom of the landform (water head) causes water to flow directly into the narrow floor of the valley maintaining saturated conditions here.

    In places, active springs and seepages occur relatively high on the valley sides just below the bounding steeper slopes and these are thought to mark the junction of the Chama and Becton Sands.

    These seepages provide the wetness needed to support the varied valley mire communities.

    Artificial drainage

    Drainage has been by digging a relatively straight cut through the valley bottom (from an area of active springs) towards the (new) footbridge. This water would previously have flowed in an irregular fashion by surface flows and shallow meandering channels across the valley floor mire.

    The drainage ditch is about 180m long, bounded by spoil on the west side and generally wooded with a thin strip of maturing birch and willow along the watercourse.

    Following cutting of the artificial drain, this water would have been diverted through the drain to flow directly to the Silver Stream. Drainage would have increased the flow of water out of the bog both by diverting spring water and by taking water laterally either side of the drain.

    While the drainage here has been relatively limited, a further shallow straight grip was also dug to drain water from a small step mire above the main valley.

    Today, the main drain has become wooded and partly infilled and its function has degraded, although remnants still take considerable flows into the Silver Stream after rain.

    Part way down the drain, some surface water is diverted across the narrow flood plain creating a marshy area. At about 20m above the footbridge, this surface water returns to the drain and in the past has caused development of a nick-point causing significant erosion of the drain bed. A gravel filled wire gabion has been installed to prevent erosion developing further. Below the gabion, the channel is about 2m wide and nearly 2m deep with sides that (in 1998) were beginning to slump.

    At this lower end of the valley, a narrow grip takes water down the eastern valley side from a higher level seepage step mire. A further small drain on the west side intercepts surface water and takes it to the stream to avoid flooding of the footpath. A pool has developed below the footbridge.

    8.13.6 Vegetation

    Redhill Bog contains a range of plant communities occurring in the following habitats:

    • Valley side seepage mire with Sphagna, Drocera, Narthecium and
      Eriophorum;
    • Valley side step mire with similar species;
    • Springs and associated Soakways;
    • Swamp with Phragmites;
    • Running water within irregular drain remnant and overflow channel;
    • Willow, birch scrub along water course and drain side spoil;
    The springs at the head of the drain provide a very wet area dominated by Phragmites swamp either side of which is gently sloping land with seepage mire. Water here has a pH of about 5.

    North from the springs, a distinct valley floor develops with acidic mire communities and the drain becomes variously silted and infilled with vegetation, such that at times of higher flow, water is diverted away from the drain to flood over part of the eastern valley floor into a narrow shallow channel before passing back to the drain. This wetter area is becoming invaded with rather open Phragmites stands as oxygenation and pH values rise. Downstream of the Phragmites, the land remains very wet with shallow irregular surface flows supporting bog pondweed, Potamogeton polygonifolius.

    The valley sides support a mosaic of seepage mire on peat and more seasonally saturated areas of wet heath.

    8.14 HOLMHILL BOG

    8.14.1 General description

    Holmhill Bog (SU 264 022) in Rhinefield Parish is in the open forest about 6km southwest of the town of Lyndhurst and 4km west of Brockenhurst. Together with the adjacent Redhill Bog, Holmhill Bog provides a tributary water source to the Silver Stream which itself flows into the Ober Water, a tributary of the Lymington River which enters the Solent at the coastal town of Lymington.

    The mire was examined by Ron Allen in February 1998 (Allen 1998), is located upstream from the Silver Stream and comprises a narrow valley divided into:
    1. a level valley bottom mire into which has been cut a drain,
    2. gently sloping lateral seepage mires on lower valley sides with springs and pools, and
    3. discontinuous step mires.

    The mire has suffered headward erosion following drainage (FC 2002). Four dipwells were installed in the valley mire for the mire restoration project and monitored from March 1999 to October 2000. Restoration work completed in August 2000 involved filling drainage channels and erosion points and this has resulted in high water levels.

    The lower part of Holmhill Bog has been drained by a central cut drain which appears to take water from a high quality valley mire habitat at the head of the valley and so would appear to be drier than in the past.

    The drawing at the end of this section shows the layout of the mire types.

    8.14.2 Landform

    The main part of Holmhill Bog is located within a relatively narrow west-east trending valley arising from a distinct re-entrant into an extension of the Wilverley Plain gravel plateau. The head of the peat filled valley is at about 42m AOD and the lowermost point of the study area at the junction with the head of the Silver Stream (taken as at the footbridge) is about 30m AOD giving a total fall of about 12m over a distance of about 800m.

    In detail, the valley structure is complex with short steep slopes at upper edges, leading to broad gentle slopes interrupted in places by level very wet areas below seepage steps. There is a distinct valley floor where the land is level in cross section, but distinctly sloping down the length of the valley.

    Only the eastern 200m of the valley is directly affected by drainage, although there are likely to be less easily detectable secondary effects further upstream.

    8.14.3 Geology

    The Holmhill Valley is entirely cut into Barton Sands (now divided into the upper fine-grained sands of the Becton Sand and the lower clayey silty sands of the Chama Sand) described by the Institute of Geological Sciences (MAR 122 1982) as pale yellow fine quartz sands.

    The upper source of Holmhill Bog in Hinchelsea Moor is cut into a narrow irregular plateau developed in flinty terrace deposits (Plateau Gravels). While Barton Clay underlies the Barton Sands, this appears at this location to be at some depth with the nearest outcrop some 2km to the west at the head of the Ober Water.

    Stratigraphy Quaternary Terrace (Plateau) Gravels at head of valley
    Tertiary Barton Sands (Becton Sand over Chama Sand)
    Barton Clay at depth only

    The valley floor has thin peat (generally between 0.5 and 1.8m thick) over gravels, the gravels likely to be material washed down the valley from the plateau during the Devension cold period.

    8.14.4 Peat deposits

    Four auger borings were made, two in each to two transects 50m and 121m upstream from the bridge.

    Two downstream borings were in the very narrow valley bottom mire and were characterized by very fluid watery peat and soft sediment up to 80cm depth.

    Land around the bore nearest to the stream had about 30 per cent of the surface as open pools about 5-10cm deep supporting Potamogeton polygonifolius with frequent Molinia, Eriophorum and Rhynchospora; occasional Myrtilus; and rare Erica tetralix. Phragmites occurred close to the stream. The profile had raw Sphagnum peat to 15cm depth over unconsolidated very fluid watery peat to 80cm, over flinty loamy fine sand with Phragmites remains.

    Land around the bore nearer to the edge of the mire had about 10 per cent open water to 2cm deep with abundant Eriophorum and Sphagnum, occasional Erica tetralix, and rare Narthecium. The profile had 20cm of raw Sphagnum peat over very fluid watery humus-rich loamy fine sand with fibrous roots to 35cm over flinty fine sandy loam to at least 80cm depth.

    Of the two upstream borings one was in the valley floor mire and the other on a seepage step mire. Both were characterized again by fluid peat.

    The valley floor here had about 40 per cent of the surface flooded to about 5cm deep with 50 percent Sphagnum cover and with locally abundant Phragmites and Eriophorum, abundant Rhynchosporum and occasional Myrtilus and Erica tetralix. The profile had a thin layer of live Sphagnum over very fluid watery humus to 35cm over saturated sandy humified peat to 55cm over flinty fine sandy silt loam to at least 80cm depth.

    The step mire had about five per cent free surface water with about 30 per cent Sphagnum cover with frequent Erophorum, Erica tetralix, Molinia, Carex panicea and occasion Calluna. The profile had fluid or very soft humified peat to 65cm depth over flinty fine sand.

    8.14.5 Hydrology

    The Semi-natural State

    Based upon older geological mapping, it would appear that the Terrace Gravels provide a wide permeable aquifer through which rain water percolates into the Barton Sands to form groundwater held within the sands over the Barton Clay at depth. This groundwater cannot descend through the deeply underlying Barton Clay and so remains ‘perched’ above it.

    Given the more modern interpretation of the sandy Tertiary strata it is more likely that water from the river terrace deposits passes down into the permeable Chama Sand to be perched over the less permeable clayey silty sands of the underlying Becton Sand.

    This means that groundwater has to flow laterally through the Chama Sand where it emerges in valleys around the plateau edge at the junction of the Chama Sand and the Becton Sand. In this instance, water flows slowly through the Chama Sands to emerge as seepages at the sides of the Holmhill Bog valley. It is also likely that the pressure difference between the top and bottom of the landform (water head) causes water to flow directly into the narrow floor of the valley maintaining saturated conditions here.

    In places, active springs and seepages occur relatively high on the valley side just below the bounding steeper slopes.

    These seepages provide the wetness needed to support the varied valley mire communities.

    Artificial drainage

    Drainage has been by digging a drain about 200m long in the valley floor of the lower part of the mire. Spoil was placed mainly in a low but near continuous bank a few metres away on the northern side.

    The upper 100m of the drain, where the ground is wetter, is somewhat irregular and follows local topography while the lower part is a straight cut. The water would previously have flowed in an irregular fashion by surface flows and shallow meandering channels across the valley floor mire in such a way as to keep the mire wet at all times.

    Following cutting of the artificial drain, this water would have been diverted through the drain to flow directly to the Silver Stream. Drainage would have increased the flow of water out of the bog both by diverting spring water and by taking water laterally either side of the drain.

    The lower part of the drain is virtually straight cut and carries significant flows of water in a well defined, but now partly degraded channel.

    In addition, a new cut was made in the southern-most part of the mire to provide a direct link to the head of the Silver Stream.

    Since excavating the drain, part of the course has become wooded and tree growth into the drain has slowed the flow in places, leading to development of wetter land either side of the drain, which in some places has led to the development of more natural appearing water courses.

    Past restoration work

    Rapid water flows have caused the development of erosion channels just upstream of the present footpath. Within the last few years, this erosion has been prevented by inserting gabions (wire stone filled cages) into the channel.

    While these gabions have effectively prevented erosion, they have not reduced the overall flow of water out of the mire. Today, the main drain has become wooded and partly infilled and its function has degraded, although remnants still take considerable flows into the Silver Stream after rain.

    8.14.6 Water chemistry

    Acidity, and hence nutrient balance, varies in different parts of the system. Bog pools in contact with Sphagnum bog-mosses are very acidic with pH values of about 4, but as water flows over the surface of the mires, pH levels rise and in the stream the pH level rises to about 6. Increases in pH coupled with increased oxygenation as water flows more rapidly through the system reduces the typical mire characteristics of the water such that sensitive calcifuge flora becomes lost to more aggressive reeds.

    8.14.7 Vegetation and habitats

    Holmhill Bog supports a fine range of mire and swamp communities and the upper part in particular appears almost totally undisturbed, other than by grazing livestock, and gives a good impression of how the New Forest valley mires would have looked prior to drainage. Habitats include:

    • Valley side seepage mire with Sphagna, Drocera, Narthecium and
    • Eriophorum;
    • Valley side step mire with similar species;
    • Springs and associated soakways;
    • Small pools;
    • Tussock sedge swamp;
    • Swamp with Phragmites;
    • Running water within drain and overflow channels;
    • Willow, birch scrub along water course and drain side spoil.
    The southern side of the drain supports birch and willow scrub.

    The soakways at the head of the drain support mixed wetland communities with large tussocks of greater tussock sedge and patches of bog myrtle.

    Very wet land at the head of the artificial drain supports tall reedswamp and the drain appears to arise within this area. For the next lower 50-100m the land remains wet with shallow pools but the mire becomes less wet, and with a higher proportion of grasses, as soon as the straight stretch of drain is reached.

    Silting of the lower part of the channel together with ingrowing willow scrub (above the gabion) has led to a small overflow channel developing.

    The valley sides support a mosaic of gently sloping seepage mire and level areas of step mire on peat as well as more seasonally saturated areas of wet heath. These have not been affected by the drainage because they are fed directly from groundwater seepage.

    8.15 SILVER STREAM MIRE

    8.15.1 General description

    The Silver Stream (SU 269025), a small but rapidly flowing stream in Rhinefield Parish, is in the open Forest and takes water from two tributary acidic mire systems known as Redhill and Holmhill Bogs respectively. The combined flows pass through a much-modified watercourse to reach the Ober Water, a tributary of the Lymington River, which enters the Solent at the coastal town of Lymington.

    Silver Stream Mire has had severe damage following drainage (FC 2002) and the stream has been extensively modified to form a relatively straight drain and in places is artificially straight with steep, near vertical sides. Deepening of the stream course to create a drain, has both increased the flow out of the headwater tributary mires and removed water from wetland either side leading to a general drying of the mire and wetland system, although the stream course must now be wetter with deeper water and faster flows.

    The mire was examined in February 1998 (Allen 1998).

    8.15.2 Landform

    The Silver Stream valley is broad, shallow and relatively simple in form, widening towards the Ober Water but with some steeper bounding slopes. There are relatively level surfaces either side of the stream with gently rising land to either side.

    8.15.3 Vegetation

    The Silver Stream watercourse contains varied features from gravelly areas with shallow rippled flow (riffles) to silty stretches together with areas of deeper and more rapid flow in channels.

    The vegetation of the water courses has not been described in detail but includes areas of Sphagnum bog-mosses on slumped material and areas of Hypericum elodes and Potamogeton on the sides of flowing streams. In places, the narrow channels are strongly shaded by overtopping mature heather bushes.

    To the west side is a bounding area of tussocky Molinia grassland with areas of wet and humid heath forming a strip about 20-30m wide, beyond which the land rises slightly providing a seepage mire with Sphagnum, Eriophorum and other bog plants.

    To the east is mainly grazed humid heath, although the Ordnance Survey map shows marsh symbols. It may be that former wetland is now lost because of drainage.

    The middle stretch is bounded on the east side by tall willow scrub, downstream of which the land to the east is drained by the herringbone channels.

    The northern portion has been more recently straightened and some control of flows attempted by placing stakes across the streambed.

    At one time, the stream passed directly to the Ober Water close to Puttles Bridge on the public highway, but now the route is a little to the south and the original course is a narrow irregular marshy area.

    One-time conifer plantations alongside the lower part of the stream have now been felled giving a more open aspect to the stream, and public access has been improved by providing a new car park nearby.

    8.15.4 Geology

    The Silver Stream valley is entirely cut into Barton Sands described by the Institute of Geological Sciences (MAR 122 1982) as pale yellow fine quartz sands. More modern geological mapping (not covering the Silver Stream area) divides the Barton Sands into an upper part comprising fine-grained sands of the Becton Sand and a lower part comprising clayey silty sands of the Chama Sand. It is likely that the Silver Stream is developed over the lower less permeable Chama Sand and on which mire deposits would have developed. The upper tributary valleys (containing the Redhill and Holmhill Bogs) are incised into the gravelly Wilverley Plateau and these gravels are likely to have become downwashed to form the gravelly bed of the stream and extend laterally as a thin spread across the lower part of the valley as flinty Head.

    While Barton Clay underlies the Barton Sands, this appears at this location to be at some depth with the nearest outcrop some 2km to the west at the head of the Ober Water and wetness is more likely to be derived from the junction of the Becton Sand with the underlying Chama Sand.

    Stratigraphy Quaternary Terrace (Plateau) Gravels at head of valley
    Flinty Head in valley bottom

    Tertiary Barton Sands (Becton Sand over Chama Sand)
    Barton Clay at depth only

    The valley floor has thin peat (generally less than 1m thick) over gravels, the gravels likely to be material washed down the valley from the plateau during the last Ice Age.

    8.15.5 Peat deposits and soils

    Eight hand auger borings were made on land west of the Silver Stream by Ron Allen in February 1998.

    Borings 1, 2, 3 and 4 were made in a transect in the north of the study area in an area of wet heath. Borings 5 and 6 were made in a short central transect to the south and borings 7 and 8 were made in another short transect further south again.

    The northern transect showed peat depths from the stream to the mire edge of between 27cm, 28cm, 20cm and 16cm over flinty heterogeneous loamy material. The central transect had peat depths of 33cm over mineral or gravelly substrates and the southern transect had between 18 and 35cm of peat over gravel.

    8.15.6 Hydrology

    The semi-natural state

    The Terrace Gravels provide a wide permeable aquifer through which rainwater percolates into the permeable Becton Sands to form perched groundwater held over the less permeable Chama Sands. Water in the Chama Sands may in turn be perched over the very slowly permeable Barton Clay at depth.

    This means that groundwater has to flow laterally through the Becton Sands, where it emerges in valleys around the plateau edge. In this instance, water flows through the Becton Sands to emerge as seepages on valley sides, at the junction with the Chama Sand, such as those around Holmhill and Redhill Bogs. This water flows through the Silver Stream and is joined by water from seepages either side of the stream and from bed flow.

    Prior to drainage it is assumed (following discussion with English Nature staff) that the land either side of the stream was wetter than today, with a greater depth of peat. This means that the natural hydrology is likely to have been substantially modified following artificial drainage.

    Artificial drainage

    Today, the Silver Stream flows in a primarily artificial watercourse which, from the footbridges at the bottom end of the tributary bogs to the Ober Water, is about 610m long.

    It is assumed that prior to drainage, there was a pre-existing watercourse taking excess drainage from the upstream mires.

    Following digging of drains into Holmhill and Redhill Bogs, the stream would have had to have been deepened and straightened to take the increased flows. This was especially so as a new watercourse was opened up to take the drain flows from Holmhill Bog.

    Some wetland to the eastern side was also partially drained by placing shallow grips herring-bone fashion through the peat and peaty soils.

    Today, the watercourse has degraded from what must have been a straight canalised course with steep edges and flows in a complex channel which alternates from broad gravelly areas to linking stretches of narrow over deepened straight flume-like channels.

    Faster flows in the upper part of the stream course have led to the formation of a series of nick points at about 20m intervals. At these points, small erosive waterfalls have developed leading into small deep pools. Between them are straight stretches of drain and which have locally slumped to form wider shallow channels.

    The downstream section has been further modified in more recent years to improve flows by cutting across former meanders. While the old meanders are shown on the Ordnance Survey plan, they cannot now be easily distinguished and are presumed to have been infilled.

    The lower part of the watercourse is also typified by erosion of the valley sides at intervals, producing pale gashes in the streamside exposing the underlying gravelly Head deposits. Very often, these gashes coincide with the outfalls of the shallow herring-bone lateral drains.

    8.15.7 Water chemistry

    The acidity of the Silver Stream varies dramatically along its length. At the headwater end the stream is acidic with typical pH values of 5.5, while at the downstream end, the pH values become about neutral at 7.0 as measured in the field in February 1998.

    This change in acidity is likely to be the result of groundwater interception by the over-deepened drain, so that the acidic surface flows become gradually diluted by neutral groundwater.

    8.16 CRAB TREE BOG

    8.16.1 Setting and geology

    Crab Tree Bog (SU266025) is just west of the Silver Stream and forms a small short tributary valley of the Ober Water.

    The geological setting is very similar to Redhill and Holmhill Bogs. Modern geological mapping is not available and current maps (British Geological Survey Sheet 330 and the Sand and Gravel Resources Map) show that most of the catchment is on the Barton Sands and a small part may be on the Plateau Gravels on Holm Hill. The Sand and Gravel Resources Map further indicates that the valley is underlain by gravels.

    8.16.2 Hydrological conceptual model

    It is assumed that the water collects from the wider relatively permeable catchment to arise by lateral seepage and spring action into this small valley in which flinty Head deposits have accumulated with a surface accumulation of peat. As with the other valleys, the water table is probably high while the detailed distribution of plant communities is controlled by soil conditions developed on somewhat heterogeneous Head deposits.

    8.17 HOLMSLEY BOG

    8.17.1 Setting and geology

    Holmsley Bog (SU220018) is a complex area along the uppermost part of the Avon Water and including parts of several small tributary headwater streams to the west and north.

    The 1:50 000 scale British Geological Survey sheet indicates that the Avon Water valley bottom here has:
    • A thin ribbon of Alluvium set in a
    • Head infilled valley cut down successively through:
    • River Terrace Deposits (exposed to the north and south),
    • Headon Formation (outcropping below the gravels and forming a wide catchment to the west), over the
    • Becton Sand forming the lower valley sides where not overlain by Head.
    8.17.2 Hydrological conceptual model

    From the geological relations it would appear that the headwaters are derived from the wider Headon Formation catchment and so are likely to be calcareous. Water off the Terrace Deposits may be acid and in places where the gravels overlie the Becton Sand may contribute acidic influences to the mire, elsewhere the acidity may be neutralized by a stronger calcareous influence off the Headon Formation.

    8.18 LORDS OAK

    8.18.1 Setting and Geology

    Lords Oak (SU263174) is a small valley mire just south of Lords Oak to the east of Nomansland and on the very northern edge of the New Forest. From the 1:25000 scale Ordnance Survey map, Lords Oak mire appears to occur on a slightly irregular slope.

    The 1:50000 scale British Geological Survey sheet 315 indicates that this area is underlain by the Marsh Farm Formation. The Marsh Farm Formation is described as laterally variable carbonaceous laminated clays with thin beds of fine-grained sands; and sands with clay beds and laminae. The surface deposits are likely to be thin Heads derived from these geologically varied materials.

    8.18.2 Hydrological conceptual model

    Lord Oak Bog appears to be a valley-side seepage on somewhat variable deposits and with water flows that are likely to be derived from:

    • surface water off slowly permeable land and from
    • groundwater passing laterally through sandy seams and arising on the valley side as springs and seepages.
    The water supply is thus likely to be a mix of surface and seepage flows determined by the detailed disposition of surface deposits in relation to slope characteristics.

    8.19 MATLEY BOG

    8.19.1 Setting and Geology

    Newbould (1960) describes Matley Bog (SU3307) as:

    • On Barton Sand, some drainage from wooded Headon Beds;
    • Fairly narrow valley, well defined central stream, partly artificial;
    • Central flushed alder carr and a narrow marginal zone with Sphagnum-rich vegetation.
    Tubbs (1986) explains that the central flows of Matley Bog, which receive water from the Headon Beds and Barton Clay, are about neutral in reaction.

    Brewis et.al. (1996) describe Matley Bog (SU334071) as being on a wet acid-flushed north slope.

    The 1982 edition of the 1:25000 scale Ordnance Survey plan shows the bog as a linear feature along the southeast facing (northside) footslope to an east flowing tributary of the Beaulieu River and including a small re-entrant valley on the same slope. The area depicted as marsh on the 1996 edition of the same map is restricted to the re-entrant valley. The tributary takes its source waters from the west in the vicinity of Lyndhurst and Park Ground Enclosure.

    The north side of the valley here (including the small re-entrant valley) is shown on the 1987 edition of the British Geological Survey sheet 315 as having cut through the following sequence of deposits:

    • Terrace deposits (a small hilltop remnant);
    • Becton Sand (middle slope); and the
    • Chama Sand (footslope).
    The valley floor is shown as having a thin ribbon of alluvium.

    The source streams of the tributary arise in part from these same deposits, and also from the Lower Headon Formation.

    8.19.2 Hydrological conceptual model

    Surface rain water is likely to filter through the more permeable Terrace Deposits and the fine-grained sands of the Becton Sand catchment down to the less permeable clayey silty sands of the Chama Sands where some will percolate down into the Chama Sand and some will flow southwards towards the valley. Springs and strong seepages would be expected on the middle slope close to the Chama/Becton Sands junction and slower but persistent seepage on the Chama Sand footslope. This water is likely to be acidic, being sourced from surface water percolating through podzols on nutrient poor sandy deposits.

    As with all of these mires, the detailed disposition of seepages, springs and perched groundwaters is likely to depend upon the characteristics of thin Head deposits that infill minor hollows and cover footslopes.

    The water in the stream is likely to be sourced from: a. acidic seepages off the bog; and b. from the west where the source streams arise in part off the more calcareous shelly clays, silts and very fine sands of the Lower Headon Beds.

    8.20 STONEY CROSS

    8.20.1 Setting and Geology

    The location at SU250125 appears to be associated with a small stream within a re-entrant valley head set into the southern part of Janesmoor Plain immediately east of a car park. This valley head contains a small tributary headwater stream of the Coalmeer Gutter which flows east through Long Beech Enclosure.

    The 1987 edition of the British Geological Survey sheet 315 shows the higher land of Janesmoor Plain as being underlain by 3rd and 4th terraces of the Older River Gravels, a deposit of flints in a generally sandy clayey matrix, often more permeable in its upper part than its lower part. The valley passes east over Head Gravel at the edge of the terrace deposits before passing on to the Barton Clay. This is the ideal situation for seepage step mires to occur and Tubbs (1986) refers to seepage steps in this area.

    8.20.2 Hydrological conceptual model

    A mire in this situation would be expected to be sourced from seepage water off the moderately slowly permeable and strongly podzolised Older River Gravels from where water would flow into heterogeneous Head deposits overlying the very slowly permeable Barton Clay. The upper part of the mire would be expected to be fed by strongly acidic springs and seepages off the gravels with the lower part being affected by surface water on slowly permeable Head deposits and the less acidic Barton Clay.

    8.21 STONEY MOORS

    8.21.1 Setting and Geology

    Brewis et.al (1996) indicate that this is one of the finest calcareous valley mires fed by water from the Headon Beds with an alkaline rich-fen community on a spring line. Wetland is shown on the 1:25000 scale Ordnance Survey map as developed along two small valleys arising off high land in the south of the Forest and to the north of Holmsley Camping Site and which feed ultimately into the Avon Water.

    This area (SZ 215995) is shown on the 1:50 000 scale 1991 British Geological Survey sheet 329 as having re-entrant valleys arising off the higher River Terrace Deposits and which flow onto lower ground formed on the Headon Formation.

    8.21.2 Hydrological conceptual model

    Water in the mire appears to be sourced off the edge of rapid to very rapidly permeable flinty sandy River Terrace Deposits where it flows onto the more moderately permeable shelly clays, silts and fine-grained sands of the Headon Beds. Initial acidic flows are thus likely to become increasingly calcareous as they flow over the shelly fine-grained Headon Beds. The detailed disposition of peaty deposits are likely to be controlled by heterogeneous Head deposits from off the sandy Terrace Deposits and the upper part of the heavier Headon Beds leading to a variety of wetlands on seepages and springs and on surface waterlogged less permeable ground.

    8.22 WIDDEN BOTTOM

    8.22.1 Setting and Geology

    Brewis et.al (1996) indicate that Widden Bottom (SZ290994) is a calcareous marl-bog.

    This valley mire is in the south of the Forest along a northeast flowing headwater tributary of the Passford Water to the northeast of Sway village. The northern valley-side sources to the mire may have been partly disrupted by the embanked Brockenhurst railway line.

    The 1975 edition of the Geological Survey of Great Britain sheet 330 (based upon mapping published in 1885-1893) shows that the catchment of Widden Bottom is on the Plateau Gravel (River Terrace Deposits) to the south and west. The valley passes rapidly onto the Osborne and Headon Beds (taken to be the equivalent of the Headon Formation of more recent geological mapping).

    8.22.2 Hydrological conceptual model

    Water in the rapidly permeable Plateau Gravel catchment is likely to be perched over the underlying shelly clays, silts and fine sands of the Osborne and Headon Beds. The Widden Bottom valley is likely to be cut down through the junction of the two deposits creating springs and seepages that in part will be calcareous. The main part of the mire is likely to be developed on heterogeneous Head deposits formed from the gravels and the underlying strata and their disposition will determine the localized surface water regimes.

    8.23 WILVERLEY BOG

    8.23.1 Setting and Geology
    Brewis et.al (1996) describe this as one of the finest mires and being a linear valley-mire along the north side of the Avon Water (SU244001). The mire has sequences of wet heath and mire communities with pools, runnels and hollows with acidic water supplied off plateau gravels and Eocene sands with a main stream influenced by base-rich water from the Headon Beds.

    The 1975 edition of the Geological Survey of Great Britain sheet 330 (based upon mapping published in 1885-1983) shows the Avon Water valley floor here to be underlain by peat. The northside of the Avon Water valley here has cut down through Plateau Gravel (River Terrace Deposits) of the Wilverley Plain into the underlying Osborne and Headon Beds (taken to be the equivalent of the Headon Formation of more recent geological mapping), and the further underlying Barton Sands (taken to be the Becton Sand of modern mapping). The valley footslopes and valley bottom (below the peat) are likely to be lined with heterogeneous Head deposits derived from the varied materials upslope.

    8.23.2 Hydrological conceptual model

    The mire on the north side of the valley is likely to be sourced from acidic water off the Plateau Gravels to the north and which water arises as valley side seepages before flowing over the Headon Beds and into the Barton Sands. How water reaches the mire will depend upon the character and disposition of mixed Head deposits. The varied character of the deposits means that the water will be likely to be acidic and base-poor in places and base-rich elsewhere.

    8.24 WARWICK SLADE BOG

    Forestry Commission (2002) explain that this is a well studied New Forest seepage and valley mire (SU 276067) with no obvious or known drainage. Barber (1975) explains that pollen sequences are similar to Church Moor.

    The 1:25000 Ordnance Survey Map shows this mire to be along the south flowing Highland Water.

    The 1987 1:50 000 scale British Geological Survey sheet 315 shows that the Highland Water here flows through a narrow ribbon of Alluvium which here passes from the clayey, silty fine sands of the Chama Sand onto the gravelly sands of a large area of undifferentiated river Terrace Deposits.

    Two auger bores were made in March 1999. One bore within a Sphagnum lawn with Molinia and Erica had humic gley soils with Sphagnum peat to 22cm depth over loamy humified peat to 32cm depth over sandy silt loam to 45cm over gravels. The second bore was in very wet ground with 90% cover of Sphagnum with Molinia, Myrica and frequent Erica and Juncus sp. and revealed raw oligofibrous peat soils with semi-fluid peaty material to 38cm over semi-fibrous Sphagnum and woody peat to 78cm over gravel.

    Water sources to the seepage mire are thus likely to be primarily from off the Terrace Deposits and those for the valley mire are likely to be from off the Chama Sand. The disposition of Head deposits will be controlling the precise water supply to the mires here.

    8.25 DUCKHOLE BOG IN MARKWAY ENCLOSURE

    8.25.1 Setting and geology

    A mire system (SU240023) seriously damaged by forestry drains and by one large peripheral drain (FC 2002) and in which extensive restoration works have been undertaken. The upper source area of the valley was previously forested until recently destroyed by fire. Forest clearance works have opened up the mire and which can now be seen as a fine example of a seepage mire feeding down into a narrow drained valley bottom.

    The 1:25000 scale Ordnance Survey plan shows the valley to be narrow and steep sided and re-entrant into the Wilverley Gravel Plateau about 7km west of Lyndhurst. The valley bottom stream flows eastwards out of Markway Inclosure and then northeast to join the Ober Water. The name Duckhole Bog is generally given to that part of the bog outside of the forested inclosure.

    Allen (1998) explains that the head of the bog is at about 50m AOD, and the lowermost point at the eastern edge of the Inclusure is about 39m AOD. This gives a total fall of about 11m over a distance of about 600m. In more detail, the valley sides generally get steeper to the east, but individual faces are divided into steeper and less steep portions and these directly affect the local hydrology and so also the mire vegetation.

    The 1975 edition of the Geological Survey of Great Britain sheet 330 (based upon mapping published in 1885-1983) shows that the Duckhole Bog valley is cut into a broad irregular plateau developed in flinty terrace deposits (Plateau Gravels). The slopes of the valley are cut into the underlying Barton Sands which are described as pale yellow, fine quartz sands. The bottom of the valley appears to be cut into the Barton Clay.

    Stratigraphy Quaternary Terrace (Plateau) Gravels
    Tertiary Barton Sands
    Barton Clay

    8.25.2 Habitats and vegetation

    Duckhole Bog contains a range of plant communities occurring in the following habitats:

    Valley side seepage mire with Sphagna, Drocera, Narthecium and
    • Eriophorum;
    • Valley side step mire with similar species;
    • Bog pools and associated Soakways;
    • Marsh with Molinia and Myrica;
    • Swamp with Phragmites;
    • Open water (artificial ponds);
    • Running water (drain bottom);
    • Birch clumps and individual trees;
    • Bracken (on banks and mire margins).
    Unfortunately, most of these habitats are severely degraded by past drainage operations which together with misplaced forestry and fire have served to almost destroy the whole mire ecosystem. Fortunately, the hydrology remains intact and it was proposed to undertake restoration works allowing the vegetation to recover in due time.

    8.25.3 Description

    The bog is conveniently divisible into an upper western part and a lower eastern part separated by a forest track. This description relates to the site prior to mire restoration.

    The main features are indicated in Drawing FC/DHB/Hydro.

    Western Part

    The main mire on the northern side is drier in the upper western part and becomes progressively wetter to the east as the valley deepens, slopes increase and valley side seepages develop. The valley side tends to be divided into moderate slopes with areas of more gently sloping step mires. Upper slopes have Sphagnum-rich seepages and bog pools, sometimes with soakways running down slope. Lower slopes are complex with areas of tall Molinia tussocks, locally with Myrica and, in places, level seepage areas with Phragmites. Much of the mire area has been gripped for forestry and this has led to partial drainage. However, drainage has been less drastic than in the Eastern Part and the effects of fire less disastrous.

    The stream arises as a seepage, is culverted under a forest ride and passes to a one time pond (now Molinia marsh) from which it flows east. The watercourse has been canalized to form a drain which is at first deeply dug with steep almost vertical sides but soon widens and becomes infilled with almost continuous Sphagnum. As flows increase down stream, more of the watercourse becomes open water. There is a modern fenced off-line pond with steep sides at the lower end.

    The southern side of the valley is less wet and only develops into mire at the eastern end where mire vegetation only survives in the deeper and lowermost wetter grips.

    Eastern Part

    Again, it is the northern side that supports the wider area of mire communities although the effects of fire and forest gripping have been more devastating here.

    Moderate slopes with severely degraded seepage mire tend to become more gently sloping in the east where small areas of step mire remain. Downslope, and towards the stream, the slopes become steeper with springs and seepages. Land adjacent to the stream becomes flatter and more level towards the eastern boundary.

    The stream is variable in its profile but contains flowing water for its whole length. In places it is deeply incised (presumably within a cut trench), but elsewhere broadens slightly. Nick points have developed in places forming small waterfalls with plunge pools below and which are slowly eroding headwards along the stream. At the top end, a small in-line embanked pond with Phragmites swamp has a steep outfall creating a pronounced waterfall.

    The southern side is also severely gripped and has less remnant mire communities and is partly covered in Bracken.

    8.25.4 Hydrological conceptual model

    The Terrace Gravels provide a wide permeable aquifer through which rainwater percolates into the Barton Sands to form groundwater. This groundwater cannot descend through the underlying Barton Clay and so remains ‘perched’ above it. This means that groundwater has to flow laterally through the Barton Sands where it emerges in valleys around the plateau edge. In this instance, water flows through the Barton Sands to emerge as seepages at the sides of the Duckhole Bog valley.

    These seepages provide the wetness needed to support the varied valley mire communities. (See schematic cross section below).

    Prior to drainage for forestry and grazing, the seepages would have slowly shed water onto the valley sides supporting a wide range of acidic mire habitats including wet heathland, valley mire, bog pools and linear soakways together with wet woodland and some open water and swamp in the valley bottom.

    Forestry drainage prior to planting included:
    • Straightening and deepening the central stream which very effectively increased the flow of water out of the bog;
    • Digging of grips and herring-bone drains on the lower valley slopes, which rapidly removed water from the valley sides.
    So effective were these grips at draining the critical surface layers of the soil that in many areas of Duckhole Bog, the only mire vegetation was at the lower ends of the furrows.

    8.26 HOLMSLEY RIDGE BOTTOM (LITTLE HOLMSLEY AND CARDINAL HAT)

    8.26.1 Setting and geology

    The 1:25000 Ordnance Survey map shows that Holmsley Ridge Bottom is to the south of the Holmsley Ridge (SU 218006) and forms the head of a valley passing eastwards by Cardinal Hat, through Holmsley Inclosure and so to the Avon Water. No marsh symbols are shown on the OS map.

    The 1991 1:50000 scale British Geological Survey sheet 329 indicates that the valley bottom contains a thin ribbon of Alluvium and that the lower valley sides and shallow side valleys are infilled with Head.

    The valley is cut into the Headon Formation with the Lyndhurst Member (extremely sandy clay and clayey sand) formering the lower and middle slopes. To the south the upper valley side is formed of the Upper Headon Beds (shelly clays, silts and sands). Higher land to both north and south is capped with River Terrace Deposits. The wider catchment comprises wide spreads of the Headon Beds and River Terrace Deposits.

    8.26.2 Hydrological conceptual model

    The wider catchment is variously on the rapidly permeable River Terrace Deposits and the moderately slowly permeable Headon Beds and so flow towards the mire is likely to be somewhat variable and often base rich. In the vicinity of the mire, water flowing slowly out of slopes formed on the sandy clays and clayey sands of the Lyndhurst Member, feeds into areas of heterogeneous Head in low-ways. The characteristics of the Head deposits will control the nature of the mire substrate and its water regimes.

    8.27 MILKING POUND BOTTOM

    8.27.1 Setting and geology

    Milking Pound Bottom (SZ296990) is a footslope on the upper part of the Passford Water in the south of the Forest and adjacent to a railway line and down stream from Widden Bottom previously described.

    The 1975 edition of the Geological Survey of Great Britain sheet 330 (based upon mapping published in 1885-1893) shows that the catchment of Milking Pound Bottom is on the Plateau Gravel (River Terrace Deposits) to the south and west. The valley passes over the Osborne and Headon Beds (taken to be the equivalent of the Headon Formation of more recent geological mapping).

    8.27.2 Hydrological conceptual model

    Water in the rapidly permeable Plateau Gravel catchment is likely to be perched over the underlying shelly clays, silts and fine sands of the Osborne and Headon Beds. Spring and seepage water flows through or over the Osborne and Headon Beds and which forms the Milking Pound Bottom valley and so it is likely that water flows will be calcareous. The main part of the mire is likely to be developed on heterogeneous Head deposits formed from the gravels and the underlying strata and their disposition will determine the localised surface water regimes.

    8.28 PEAKED BOTTOM AND SHIPTON BOTTOM

    8.28.1 Setting and geology

    The two valley heads of Peaked Bottom join to form Shipton Bottom (SZ363994) and comprise a short drainage system arising from southwards flow through a valley re-entrant into Beaulieu Heath.

    The 1975 edition of the Geological Survey of Great Britain sheet 330 (based upon mapping published in 1885-1893) shows that Beaulieu Heath is a wide expanse of Plateau Gravel (River Terrace Deposits) and that the twin valley head system has eroded through the gravels down to the underlying Osborne and Headon Beds.

    8.28.2 Hydrological conceptual model

    The Plateau Gravel is likely to be rapidly permeable and the underlying Osborne and Headon Beds (on shelly clays, silts and sands) is likely to be only moderately slowly permeable. Springs and seepages will occur where the valley sides cut across the junction of the two deposits and the outflowing water will flow over any valley bottom Head and Peat deposits. As a result the water is likely to be calcareous.

    8.29 PICKET BOTTOM

    8.29.1 Setting and geology

    Picket Bottom (SU190166) is in the west of the Forest and arises as a valley head off Picket Plain to the south but interrupted by a two level interchange on the A31Trunk Road. Detailed studies were undertaken of the valley head at Picket Post (Allen 1992) in order to develop a new sustainable drain outfall.

    The valley head

    The higher part of Picket Plain is developed on clayey flinty sands of the Plateau Gravel (Older River Gravels) and the upper parts of the valley head slopes are on Barton Sands (Becton/Chama Sands) with the valley head floor on the Barton Clay. Springs and seepages occurred at the junction of the various deposits (see cross section below).

    Detailed hand augering of the deposits indicated that the Barton Sands are covered with remnant gravels and that the Barton Clay is covered by flinty loamy and sandy Head. The soils were found to be very complex. Slopes at the edge of the plateau had flinty sandy surface layers over clay enriched subsoils and having slight seasonal waterlogging. Soils below the steeper slopes were variably affected by groundwater perched over the Barton Clay. Soils on the spring line were seasonally affected by groundwater seepage and had upper layers that dried out in the late summer.

    The stream in Picket Bottom is supplied from valley side seepages arising out of the junction between the Head covered junction between the Barton Sands and the underlying Barton Clay. Surface waters arising off the Plateau Gravels and Bagshot Beds were acidic, while water flowing in channels over the Barton Clay was neutral in reaction.

    Picket Bottom

    Picket Bottom arises from the valley head in the open Forest before passing into Little Linford Inclosure and is wholly on Head deposits over Barton Clay. The predominately clayey catchment will lead to strong winter flows and reduced flows in summer in the stream. The wetness of higher parts of the valley mire in Picket Bottom is likely to vary sesonally.

    8.29.2 Hydrological conceptual model

    Rainfall on Picket Plain infiltrates slowly through the clayey sands to arise on lower valley sides in the valley head at Picket Post as springs and seepages on seepage steps. This water feeds small waterlogged mires and from which water drains to the lower incised stream valley leading to Picket Bottom and eventually into Linford Brook and so west to the river Avon at Ringwood. Some of the water in Picket Bottom arises off the Barton Sands and Older Terrace deposits at the valley head, but most will arise from the clayey catchment either side of the valley leading to seasonal wetness in Picket Bottom.

    8.30 SHIRLEY HOLMS BOTTOM

    8.30.1 Setting and geology

    Shirley Holms Bottom (SZ294985) is close to Widden Bottom and Milking Pound Bottom previously described and is a small wetland area at the head of a small southwesterly flowing tributary stream of the Passford Water in the south of the Forest.

    The 1975 edition of the Geological Survey of Great Britain sheet 330 (based upon mapping published in 1885-1893) shows that the catchment of Shirley Holms Bottom is on the Plateau Gravel (River Terrace Deposits) to the north, east and west. The Shirley Holms Bottom valley is re-entrant into the Plateau Gravel plateau and rapidly passes over the Osborne and Headon Beds (taken to be the equivalent of the Headon Formation of more recent geological mapping).

    8.30.2 Hydrological conceptual model

    Water in the rapidly permeable Plateau Gravel catchment is likely to be perched over the underlying shelly clays, silts and fine sands of the Osborne and Headon Beds. Spring and seepage water flows through or over the Osborne and Headon Beds in the valley bottom and so it is likely that water flows will be calcareous. The main part of the mire is likely to be developed on heterogeneous Head deposits formed from the gravels and the underlying strata and their disposition will determine the distribution of localized surface water regimes.

    8.31 WHITE MOOR AND NORTH WEIRS

    8.31.1 Setting and geology

    White Moor and North Weirs occur along an easterly flowing small stream arising off Five Thorns Hill to the west of Brockenhurst.

    The 1975 edition of the Geological Survey of Great Britain sheet 330 (based upon mapping published in 1885-1893) shows that the catchment of the stream is wholly on the Barton Sands and that the lower part of the stream (at North Wiers) has a thin ribbon of Alluvium.

    8.31.2 Hydrological conceptual model

    The catchment is wholly on the Barton Sands although which part (Becton Sands or Charma Sands) remains unknown. The catchment is thus likely to be moderately rapid to moderately slowly permeable and any mire on the valley floor is most likely to be directly affected by acidic groundwater.

    8.32 BAGNUM BOG, KINGSTON GREAT COMMON NNR

    8.32.1 Introduction

    Bagnum Bog (SU 182024) is part of Kingston Great Common National Nature Reserve, situated towards the eastern edge of the New Forest near the hamlet of Crow to the southeast of Ringwood, Hampshire. This part of the NNR comprises a valley mire containing several streams, one of which contains an on-line pool. Hydrological relations and a cross section are appended to this section.

    Bagnum Bog has been the subject of a number of detailed studies for English Nature (1995) in order to develop a scheme to prevent the headward erosion of a straightened drain from reaching and draining down of a significant open water pool. The studies considered how best to either control inflows or to control outflows and so reduce the rate of flow of water in the drain. These studies involved descriptions of vegetation and soil auger borings along two transects across the bog, water sampling and analysis from representative water bodies, determination of flow directions and rates into and out of the bog. It was possible to develop a descriptive model of substrate and surface water conditions and how water was flowing into and out of the bog and its characteristics.

    The bog is about 150m wide by about 500m long and oriented NE-SW. A main canalized stream flows along the northern margin. There is a fall from east to west of about 4m.

    The key documents are:

    • Ron Allen (January 1995) Bagnum Bog: Initial hydro-ecological study
    • Ron Allen (April 1995) Bagnum Bog: Surface Water Chemistry
    • Ron Allen (October 1995) Bagnum Bog: Engineering options for reducing erosion and securing pond
    8.32.2 Vegetation Studies

    Two north-south transects, about 150m apart, were set across the mire, Transect A was located just upstream of the pond and Transect B was in the western part.

    Wildlife habitats were determined using a simple descriptive system backed up by descriptions of 1x1m quadrats. The main habitats were:

    Molinia marsh; with large Molinia tussocks variously having Myrica and Sphagnum between tussocks and with Erica tetralix on the summits. Open water was generally restricted to pools around the tussock bases which often join into irregular shallow watercourses. Drier areas have Myrica bushes rising above the Molinia tussocks and which become smaller as the wetness gradient increases. Drier areas have Rubus, Rosa and Cirsium.

    Phragmites swamp; with almost continuous shallow surface water and having short Phragmites with common Molinia tussocks and flowing water tracts that grade to mire communities.

    Valley mire; where areas of deeper water have abundant Trichophorum accompanied by Sphagnum, Narthecium, Hypericum elodes, Equisetum fluviatale and E. palustre with a small range of sedges and rushes. Potamogeton polygonifolius is common throughout. Molinia is either non-tussocky, or has only small tussocks surmounted by Erica and Myrica.
    Scrub; occurs on drier parts with Birch scrub on drier parts of the Molinia marsh or by Birch and Pine in more heavily wooded areas to one side of the open mire.

    8.32.3 Hydrology

    The main stream (including the pond) flows close to the northern boundary of the mire with the drier valley side. The stream has its headwater sources in a complex mire system including Strodgemoor Bottom, Broad Bottom and Cranesmoor. The inlet and outlet streams have been dug and pass water rapidly through the mire. The outlet stream is deeply incised and water from the mire drains directly into it. The watercourse has thin gravelly bed over Chama Sand overlying Tertiary clays (Barton Clay). The pool was dug as a flight pond with water retained by a wooden weir.

    In January 1995 there was considerable surface water flowing into the northern part of the bog from the east. This water generally flowed as a broad shallow swathe southwest along the main central axis of the mire and broadly parallel to the stream. The land here is very slightly undulating and the lower areas guide surface water flows to the southwest.

    The water was generally only slightly acidic. The stream water was about 6.3 and the surface flood water varied from about 6.3 to almost 7. More strongly acidic values were found in standing waters between Molinia and Sphagnum tussocks. It is likely that in winter, the mire is saturated with slightly acidic water, while in the summer with lowered water levels, the action of the vegetation will create a more acidic water environment.

    Studies of aerial photographs and the disposition of features on the ground suggests that the natural state of the mire is to have surface water flows, and that the watercourse and several smaller similar drains are modern structures created to drain the site and in so doing, disrupt the natural system.

    8.32.4 MIRE SUBSTRATES

    The common sequence of deposits was as follows
    • Surface organic muds associated with plant tussocks, over
    • Semi-fibrous peat associated with partly decayed surface vegetation, over
    • Humified peat with grass/sedge and Phragmites remains and some woody material and often with intercalations of fine sandy Drift, often with peaty inclusions (the sandy material is presumed to have downwashed from the upslope Tertiary Becton Sand), over
    • Flint gravel underlying the peat and sand sequences and presumed to be downwash from nearby Plateau Gravels, over
    • Tertiary Chama Sand over Tertiary Barton Clay at depth.
    Peats extended in a swathe about 50-70m south from the stream course and had a maximum recorded depth of 2.3m and with intercalations of peaty sand. Outside of this area, the peat occurs as only very thin surface deposits.

    8.32.5 WATER CHEMISTRY

    Thirty-four water samples were determined in March 1995 for a range of parameters in order to better characterise the water flows and separate different flows.

    The mire has a complex of water sources and water chemistry. In January, standing waters between Molinia tussocks had typical pH values of 4.7 to 5.7. Running water samples were between 6.5 and 6.8. Minor headwaters off Molinia marsh were typically below 5.5 but quickly rose downstream to slightly acidic to circum-neutral values. The stream had pH values of 6.0 to 6.3. pH values in the mire had reduced from slightly acidic to moderately acidic by October 1995, suggesting that water flows and depth were important in determine acidity.

    Total Phosphorus levels in the main stream and across the mire ranged from 0.88 to 1.23mg/l and which are very high levels typical of hyper-eutrophic levels. Inorganic nitrogen levels varied from 0.6 to 0.8mg/l and which are high levels typical of eutrophic systems. Alkalinities varied from 12.5 to 22.5mgCaCO3/l and which are typical of more mesotrophic conditions.

    9.0 REFERENCES

    Allen R H and Hall D (1992) A31 Picket Post Junction, New Forest, Hampshire: Remedial Works to Drainage Outfall, unpublished report for Hampshire County Council County Surveyor’s Department.

    Allen R H (1998) Restoration of Denny Bog (East) at the Bishop’s Dyke, unpublished report for the Forestry Commission New Forest Life Project.

    Allen R (1998) Restoration of Duckhole Bog, unpublished report for the Forestry Commission New Forest Life Project.

    Allen R (1998) Restoration of Redhill Bog, unpublished report for the Forestry Commission New Forest Life Project.

    Allen R (1998) Restoration of Holmhill, unpublished report for the Forestry Commission New Forest Life Project.

    Allen R (1998) Restoration of Silver Stream Mire, unpublished report for the Forestry Commission New Forest Life Project.

    Allen R (1998) Restoration of Bishop’s Dyke Bog, unpublished report for the Forestry Commission New Forest Life Project.

    Allen R (January 1995) Bagnum Bog: Initial hydro-ecological study

    Allen R (April 1995) Bagnum Bog: Surface Water chemistry

    Allen R (October 1995) Bagnum Bog: Engineering options for reducing erosion and securing pond

    Allen R H and Staines S J (1984) The New Forest in Jarvis M G and Findlay D C (Eds) (1984) Soils of the Southampton District, British Society of Soil Science, Southampton 1984.

    Allen R H (1992) A31 Picket Post Junction: Remedial Works to Drainage Outfall, unpublished report for Hampshire County Council Surveyor’s Department.

    Barber K E (1975) Vegetational History of the New Forest: A preliminary note, Proc.Hants.Field Club Archaeol.Soc 30 pp5-8

    Barber K E and Clarke M J ( 1987 ) Cranes Moor, New Forest: Palynology and Microfossil Stratigraphy in Barber (Ed) (1987) Wessex and the Isle of Wight Field Guide, Quaternary Research Association Cambridge.

    Brewis A, Bowman P and Rose F (1996) The Flora of Hampshire Harley Books

    Burton R G O, and Hodgson J M (Eds) (1987) Lowland Peat in England and Wales, Soil.Surv.Special Survey No.15 Harpenden

    Clarke L (1988) The field guide to water wells and boreholes, Geological Society of London Professional Handbook Series, John Wiley and Sons, reprinted 1992/1996.

    Clarke M J and Allen R H (1986) Peatland soil-plant relationships in the New Forest, Aquatic Botany, 25 pp167-177.

    Fisher G C (1975) Terraces, soils and vegetation in the New Forest, Hampshire. Area Institute of British Geographers pp255-261

    Forestry Commission (2001) Monitoring and Survey on the New Forest Crownlands: a report detailing work undertaken by the Forestry Commission for the EU Life II Project.

    Gilmore K (1994) Water balance of wetland areas, Conf. On The balance of Water – present and future, AGMET Gp (Ireland) & Agric.Gp.of RoyMeteorol.Soc (UK) Dublin, 7-9 Sep 1994 123-142

    Jarvis M G, Allen R H, Fordham S J, Hazleden J, Moffat A J and Sturdy R G, Soils and their use in South East England, Soil survey of England and Wales Bulletin No 15, Harpenden 1984.

    1:25,000 Soils of England and Wales, Sheet 6, South East England, Ordnance Survey for Soil Survey of England and Wales 1983.

    Legend to the 1:250,000 Soil Map of England and Wales, Soil Survey of England and Wales 1983.

    Newbould P J (1960) The Ecology of Cranemoor, A New Forest Valley Bog, J.Ecol 48 pp361-383.

    Seagrief S C (1960) Pollen Diagrams from Southern England: Cranes Moor, Hampshire, New Phytol 59 pp73-83.

    Smedema L K and Ryecroft D W (1983) Land Drainage: Planning and design of agricultural drainage systems, Batsford.

    Thomasson A J (Ed) (1975) Soils and Field Drainage, Soil Survey Tech.Mon No 7 Harpendon 1975
    Tubbs, Colin R (1986) The New Forest Collins The New Naturalist series, London

    Tuckfield C G, (1973) Seepage Steps in the New Forest, Hampshire, England Water Resources Research 9 No.2.

    Bristow, C R, Freshney E C, and Penn I E. 1991 Geology of the Country around Bournemouth. Mem. Br. Geol. Surv, Sheet 329 (England and Wales).

    Wilson E M (1983) Engineering Hydrology, McMillan Education Ltd.

    Edwards R A and Feshney E C, (1987) Geology of the country around Southampton, Mem. Br. Geol. Surv. Sheet 315 (England and Wales).

    Melville R V, and Freshney E C, (1982). British Regional Geology: The Hampshire Basin. London: HMSO for Institute of Geological Sciences.

    British Geological Survey (1987) Sheet 315 Southampton, 1:50 000 Series British Geological Survey.

    Geological Survey of Great Britain (1976) Sheet 314 Ringwood, 1:50 000 reprint of 1902 mapping at 1” to mile.

    Geological Survey of Great Britain (1975) Sheet 330 Lymington, 1:50 000 reprint of 1893 and 1963 mapping at 1” to mile.

    British Geological Survey (1991) Sheet 329 Bournemouth, 1:50 000 Series with revised stratigraphy.

    Mathers S J, 1982. The sand and gravel resources of the country around Lymington and Beaulieu, Hampshire, Institute of Geological Sciences Mineral Assessment Report 122.


    		•  
    The Environmental Project Consulting Group
    44A Winchester Road, Petersfield, Hampshire GU32 3PG
    email: Ron Allen, tel: 01730 231019,
    Copyright April 2005 Ron Allen
    Geologist, Soil Scientist, Applied Ecologist, Hydro-ecologist, Chartered Environmentalist