Report on the Doley Brook & Wetland Works

Report on the Doley Brook & Wetland works - The Acres, Gnosall.

February to March 2015.

Michael Deegan Gnosall Parish Councillor

Background The drainage work on the Doley Brook started on February 13th 2015 and took three days to complete. The work came about as a result of a meeting between Gnosall Parish Council, the Environment Agency (EA) and Staffordshire County Council Farms in May 2014.

The meeting followed an unconsented encroachment of drainage work in April 2014 to the brook beside 150m of The Acres (owned and managed by Gnosall Parish Council). The drainage works were being carried out by the new tenant farmer upstream at Plardiwick Farm (a Staffordshire County Council property). It emerged the tenant farmer believed that recent Parish Council management of the Doley Brook through The Acres was causing flooding upstream on the floodplain at Plardiwick Farm. The drainage project of the brook through the Parish Council land was subsequently agreed to test this assertion.

The work had been delayed since autumn 2014 until dry conditions in late January/February enabled the contractor (Foxley Earthworks) adequate access. The main focus of the works was to cut the vegetation on the brook to maintain a central open channel within the watercourse. This stretch of the brook runs through the Acres from the Hollies Brook confluence to the electricity sub-station by the A518 road culvert.

Above: Doley Brook looking south from Boardwalk. (1) February 13th and (2) February 16th.

1. The Acres  The Doley Brook The Doley Brook is classified by EA as a Main River and as a headwater is a tributary watercourse of the River Trent Catchment. Extensive drainage was carried out by the National Rivers Authority in 1980 to canalise the brook, which heavily modified the channel. Despite regular de-silting and drainage of the brook through The Acres until 2007, the main field to the east of the brook became increasingly boggier in the late 1990’s and much of the allotments area (created in 1981) had to be abandoned as marshland.

The Acres Restoration project in 2012 aimed to create a more sustainable future for the site and make the most of the brook and wetland. Working with EA and Farming Floodplains for the Future, the brook was cleared and re-engineered with a two-stage channel. A new silt- lagoon was installed to intercept sediment being washed down the Hollies Brook and an overflow channel (and pools) was created to take excess water through six acres of floodplain. This area was further reconnected to the brook by removal of the drainage spoil- banks, allowing the floodplain in this contained wetland to provide a huge area for flood- storage to further protect land downstream, as well as restoring a valuable wildlife habitat.

 The Works The contractor was authorised to take a more rigorous cut than planned because of the surprising quantity of silt in the channel (only three-years since it was last cleared in 2012). Over a period of three days, the contractor carried out maintenance on the Doley Brook all the way through The Acres downstream to the A518.

As well as clearing more sediment than envisaged, the contractor also removed the two log- deflectors installed to create meanders. Unfortunately the squeezed-channel had become completely clogged-up and the deflectors starting to act as dams. They were an innovative element of the 2012 project, but with hindsight there was not enough velocity or flow in the brook to scour out a meander in the watercourse.

Left: Doley Brook looking South from the boardwalk.

(3) February 13th before the works and (4) February 15th immediately after the works.

 Silt Lagoon Trap Another key objective was to clear the newly created silt lagoon. This was installed at the confluence with the Hollies Brook (in 2012) to intercept the excessive load of sediment washed down the Hollies Brook system (as a result of intensive farming practices upstream).

The lagoon was completely full of sediment and has now been fully cleared. Although this feature has proved successful, it clearly will require clearing at least once a year.

Above: The Silt Lagoon from two different angles. (5) February 13th and (6) February 16th.

 Overflow Channel The overflow channel created in 2012 through the wetland was not cleared on this occasion. There was not a significant issue with silt or weeds in the channel and this will now be addressed next autumn/winter as part of the Parish Council’s ongoing Acres and Doley Brook maintenance programme.

Left/below: Foxley Earthworks on site. (7) Feb 13th and (8) Feb 15th.

2. Water level Monitoring Photographs were taken of the gauge-board located in the Doley Brook at the most northern end of the Acres allotments. The waterlevel of the brook (and in the wetland) did appear to drop slightly during the drainage works, but has since risen closer to its initial level (despite the dry weather).

Above: Doley Brook gauge board. (9) February 13th before the works, (10) February 16th immediately after the works and (11) March 15th one month afterwards.

3. Rainfall Specific precipitation records for the site are not monitored. However, according to Met Office figures, the total rainfall recorded in nearby Stafford during February was 42mm and for early March (to the 12th) was 27mm. The Environment Agency confirm that February was drier than average and likely to be slightly cooler than average, with March continuing in the same pattern.

Nationally, Met Office statistics show that the UK has had its sunniest winter since 1929 while figures for temperature and rainfall are fairly average for the West Midlands.

Right: Rainfall Summary for England and Wales for January – March 2015 (www.gov.uk/government/statistics/weekly- rainfall-and-river-flow-summary-4-to-10- march-2015)

4. Long-term Affect

 The Acres One month after the works were completed, a further set of comparison photographs of the Acres were taken, in addition to shots of the brook and pools upstream to Doley Common SSSI.

Although the weather has remained relatively dry over the past month, the level of the brook through the Acres has remained stable and virtually unchanged since before the drainage works. This comparison is particularly marked from than from the boardwalk bridge over the brook – looking both north and south.

Above: Doley Brook looking North from the boardwalk. (12) February 13th before the works, (13) February 16th immediately after the works and and (14) March 15th one month afterwards.

Below: Doley Brook looking South from the boardwalk. (15) February 16th immediately after the works and (16) March 15th one month afterwards.

 Upstream – Plardiwick Farm to Doley Common SSSI As part of the post-works appraisal, a visit was made to the floodplain upstream to assess the effect of the clearance through The Acres. Regardless of the drainage and low rainfall, the level of the brook flowing past Plardiwick Farm and through Doley Common SSSI is close to bank-top and the adjacent pools are still holding significant water.

Above: (17) Pools adjacent to the Doley Brook. March 15th

The Plardiwick Farm field appears visibly lower in height than the immediately adjacent Doley Common SSSI land to the north. It is possible that the land was always lower. However, it is more likely the underlying peat soils have shrunk as a result of drainage during the drier decades of the 1980’s to 1990’s, when the land was able to be drained and utilised for more intensive farming-use. Weather conditions since the late 1990’s have been much wetter and climate change predictions indicate that periods of high or extreme rainfall will be more common in the near future.

Above: (18) Plardiwick Farm (left) next to Doley Common SSSI (right). Doley Brook in foreground. 7

It should be noted that the field also in the floodplain on the opposite side of Plardiwick Farm (southwest of Hollies Farm) is dominated by reeds (Phragmites australis) with scattered willows. This wetland habitat is quite extensive and will have taken many years to develop, indicating an already established high groundwater table on this side of the brook.

Above: (19) Reedbed habitat on eastern side opposite Plardiwick Farm. March 15th

It was also evident that the cultivated fields above this opposite side of the brook side are ploughed down the contours of the slopes. Although an unploughed strip of reedbed is left at the bottom, there were a number of eroded gulleys into the brook that add to the diffuse pollution downstream – showing that excessive silt being deposited into the system is clearly not just a problem from the Hollies Brook catchment.

Above: (20) Eroded gulley down arable slope into the Doley Brook. March 15th (21) Vehicle tracks into Doley Brook creating gulley channels at the bottom of an arable slope.

5. Biodiversity Value along the Doley Brook The land on either side of the Doley Brook (immediately south of Doley Common SSSI) is currently of considerable wildlife habitat importance. In particular, the lower field of Plardiwick Farm along the Doley Brook contains notable areas of open water and wet grassland. Lowland Wet Grassland and such healthy Rivers & Streams are designated as habitats on the Staffordshire Biodiversity Action Plan (SBAP).

Of particular interest was the important assemblage of wetland birds (predominantly wintering wildfowl and waders) using the Plardiwick Farm pools and surrounding wet grassland. During the March visit a flock of approximately 40 Lapwing, an SBAP priority species, was observed. There were also large numbers of Teal, Wigeon and Mallard. Lesser numbers of Snipe and Redshank were also in evidence. When disturbed, most birds flew the short distance to the adjacent Doley Common SSSI, before later returning.

Above: (22) Plardiwick Farm with the Doley Brook in foreground. March 15th Below: (23) Plardiwick Farm and (2) large flocks of wetland birds overhead

6. Findings  The Acres Despite the dry conditions, the level of the Doley Brook through the Acres has remained stable and virtually unchanged following the drainage works a month before. This supports the evidence demonstrated by EA at the May 2014 meeting, that the hydrology of the Doley Brook is strongly determined by the invert-level of the culvert below the A518 road bridge. Cross-section profiles showed the base of the concrete culvert to be higher than much of the bed-level upstream – effectively creating a weir controlling normal and low-waterlevels through the Acres and upstream to Doley Common SSSI. This means that deepening the channel upstream of the A518 road will have no effect on increasing the flow of the brook.

Above: The Doley Brook Looking North from the A518 Road Bridge; (24) Feb 13th and (25) March 15th

There is undoubtedly an excessive sediment-load being washed down the Doley Brook through the Acres from upstream – primarily via the Hollies Brook catchment, but also from sources along the Doley Brook.

This silt is chiefly due to intensive agricultural practices such as cultivation of fields right up to the edge of ditches/watercourses, ploughing downhill against the contours and ongoing canalisation of ditches and natural watercourses. Nutrients and phosphates (from agricultural fertilisers) entering the catchment and being washed downstream will also add to the problem of excessive growth of reeds within the brook channel through the Acres.

The maintenance carried out during February managed to remove much of the vegetation and silt from the main channel, however, this is very much a short-term and reactive solution. Ultimately, such intensive drainage operations are extremely damaging to the biodiversity of this natural watercourse and unsustainable as a management remedy. The removed silt also builds-up again to produce an embankment along the edge of the brook through the Acres – a detrimental feature Above: Doley Brook Looking South from A518 th that was previously removed at great cost Road Bridge; (26) Feb 13 and (27) March 15th in 2012, to open up almost six acres of the

floodplain for potential flood storage.

 Upstream - Plardiwick Farm No pre-drainage photographs of the Doley Brook upstream and the Plardiwick Farm field were taken from February, so it is not possible to show any comparison sequences. Never the less, despite the dry weather, the brook was still relatively high by mid-March and the pools holding water.

Given the scale of drainage work, low precipitation levels and time elapsed, it is evident that management of the channel through the Acres has not affected waterlevels upstream. As outlined, these levels are determined by the invert-level of the concrete culvert below the A518 road bridge.

The land along this length of the Doley Brook floodplain is extremely low-lying. Historical evidence confirms that the section of Plardiwick Farm immediately southeast of Doley Common was formerly a flood meadow – indicating how low-lying and wet the land was. Even into the 1970’s the field was a rough wetland pasture, indistinguishable from the adjacent Doley Common (see attached appendices of historical maps and aerial photographs).

It would appear that intensive farming of this field was only possible during the prolonged and relatively dry conditions experienced in the 1970’s and 1980’s, during which period it is likely there was considerable shrinkage of the underlying peat soils as they dried out. As a headwater system, the brook will always be susceptible to extreme short-term weather fluctuations, so that the brook will fall in prolonged dry weather and flood quickly after heavy or long-lasting rainfall.

Furthermore, climate change predictions indicate that the UK’s weather in the near future will overall become wetter and not drier. Staffordshire County Council expressed its considerable concerns about climate change in its 2011-14 Climate Change Adaptation Plan (www.staffordshire.gov.uk/environment/climatechange/Adaptation-Plan-Staffordshire.pdf) – this is the ideal opportunity now for Staffordshire County Council to demonstrate how it is truly adapting for climate change.

Above: (28) Plardiwick Farm with the Doley Brook in foreground – March 15th 2015

 Historical Evidence There is also considerable historical and hydrological evidence that the Plardiwick field has a long history of being inundated (see appendices).

I. Staffordshire County Council’s Environmental Record Survey in 2012 classifies it as a former water-meadow – part of a regularly flooded system along the Doley Brook.

II. Aerial photography from 1963 & 1971 clearly shows the field as part of the same wetland system as the adjacent Doley Common.

III. Photographs of Plardiwick Farm taken just five months after the last clearance of the Doley Brook (through The Acres in 2012) show the whole floodplain inundated and the Plardiwick pools completely submerged.

IV. The information provided by Vince Smith support the historical evidence showing the lower Plardiwick Farm area as a wet moor.

V. The Surface Water Flood Risk Assessment from the 2015 Gnosall Neigbourhood Plan indicates that the Plardiwick field is at high risk from surface flooding (even higher risk than much of the Acres and Doley Common SSSI).

Not included in the Appendix is EA’s Doley Brook levels survey. Available through EA, this indicated the invert-level of the culvert below the A518 road bridge is higher than much of the invert bed-level upstream and the Plardiwick field.

7. Recommendations

 The Acres In the short-term a greater effort is required to intercept excessive sediment being washed down from the Hollies and Doley Brooks before it enters the main channel through the Acres. This removal of silt will help improve the water quality of the Doley Brook and counter the volume of invasive tall- herb species from clogging the main channel.

It is crucial that damaging drainage operations such as carried out in February are not required again in the future. The long-term aim of the Acres Restoration project was to restore the natural dynamics of the watercourse and this is still valid as an effective way to manage the Doley Brook. This means retaining the two-stage channel (established in 2012) until a more natural wider and shallower profile is achieved. To do this, it will still be necessary to cut encroaching vegetation on a 3-5 year cycle, but this should be achieved by cutting a meandering channel to retain at least one third of the marginal/aquatic vegetation (in line with EA guidance) to limit the impact on aquatic biodiversity.

Gnosall Parish Council will seek to maintain a natural flow of the Doley Brook through the Acres, but in future damaging drainage operations such as dredging, will not be adopted unless it can be demonstrated that Parish Council management is impeding flow upstream (as required under the Land Drainage Act).

The long-term priority must be to address the principal cause of excessive sediment being washed down the Hollies Brook (and to a lesser extent, the Doley Brook). This will require landowners adopting more sustainable agricultural practices, which can only realistically be facilitated through a collective endeavour from the relevant statutory and voluntary organisations (EA, NE and SWT) to provide adequate support and advice to those landowners. Given the limited size of catchments of both these headland watercourses this is an achievable proposition.

Once enhanced land-use management has been achieved upstream, it should be possible to recreate a more naturally-functioning watercourse through The Acres with a self-regulating flow. Therefore this should be a strategic priority.

Above: (29) Wildlife pools on The Acres

 Upstream - Plardiwick Farm pools This report has produced two robust sample of evidence – analysis of this year’s drainage work on the Acres and historical records (including Archaeological surveys and aerial photography). There is also EA’s survey levels of the Doley Brook (including the A518 culvert invert-level) to consider.

All three sources of evidence strongly indicate that ground conditions of the lower Plardiwick Farm field is determined by a combination of the A518 road culvert, the low-lying nature of the fields within the Doley Brook floodplain and weather conditions. Realistically the only determinable influencing factor is the road culvert. Unless this is re-engineered to provide a lower invert-level, it will prove virtually impossible to guarantee drainage of the lower Plardiwick fields.

Consideration should also be given to the biodiversity value of the upper Doley Brook and adjacent wetland now in situ at Plardiwick Farm. These wetland habitats and their associated species have significant wildlife value as recognised in the SBAP and accepted by Staffordshire County Council through its responsibilities to consider biodiversity under the 2006 Natural Environment and Rural Communities (NERC) Act. The site is also adjacent to Doley Common SSSI and much of the hydrology and wildlife interest of both sites is clearly interrelated.

It is worth pointing out that many conservation organisations would spend considerable sums of money trying to recreate the conditions found on the lower fields at Plardiwick Farm – particularly to recreate a wetland situated next to such a valuable SSSI. There is huge potential for either Staffordshire County Council or the tenant farmer to utilise this biodiversity value. Entry in the new Environmental Stewardship scheme would guarantee favourable area payments to maintain the current habitat conditions, with additional payments available towards capital costs. It would still also be possible to graze the wet grassland when conditions allowed.

Natural England has already confirmed its support for entry of this part of Plardiwick Farm into the Environmental Stewardship scheme and it would certainly help to draw up the agreement. As stated at previous meetings, ongoing support with wetland expertise would be willingly provided by EA and Staffordshire Wildlife Trust specialists. The proximity to Doley Common SSSI would also enable joint working with Natural England.

It is recommended that Staffordshire County Council also liaise with Natural England to investigate the option of extending the status of the current SSSI to include the pools as part of the designated SSSI area. The wet grassland clearly has important wildlife value and even greater biodiversity potential if co-ordinated with Doley Common (plus The Acres further downstream). Designated status would not have any detrimental impact on the ownership or tenure of Plardiwick Farm holding, but could have benefits for securing funding and support for management.

Below: The A518 road culvert. (30) 2010, (31) 2011 EA site-visit and (32) 2012 during flooding

8. Report Summary

Photographic monitoring before, during and after the drainage through The Acres in 2015 indicates that the works had a negligible effect on levels of the Doley Brook upstream and the groundwater levels of the lower field at Plardiwick Farm.

Historical evidence suggests that this ‘moor’ has a long record of flooding and was formerly part of the same post-glacial wetland system as Doley Common SSSI. The Environment Agency’s levels survey of this stretch of the Doley Brook shows that it is the invert-level of the A518 road culvert that determines waterlevels upstream. It is also possible that the peaty soils of the field have shrunk as a consequence of intensive drainage 30-40 years ago.

It is recommended that Gnosall Parish Council continues to regularly manage the silt lagoon-trap on The Acres. In the long-term, however, a more strategic approach upstream to stop diffuse sediment- pollution (being washed-down the catchment) is required to prevent the brook through The Acres from silting up. This will also preclude such damaging drainage operations from having to be carried out again.

The evidence presented suggests that this low-lying and boggy field in the floodplain at Plardiwick Farm has always flooded and guaranteed drainage is not feasible. Therefore intensive agricultural use is impractical and continued subsequent drainage of the brook unnecessary.

There is significant potential, however, to change the emphasis of land-use at Plardiwick Farm by taking the lower field out of intensive agricultural production to focus management on its considerable biodiversity value and potential. The field will always be near-impossible to suitably drain so there would be little loss of agricultural production. It is recommended, therefore, that Staffordshire County Council takes advantage of the Environmental Stewardship scheme, which would provide generous area payments and capital cost contributions for wet grassland management. There would also be significant technical support provided by the relevant conservation organisations to help with ongoing management.

Gnosall Parish Council would also wish to remind Staffordshire County Council of its responsibilities to consider the biodiversity value of its landholding at Plardiwick Farm (under the 2006 Natural Environment and Rural Communities (NERC) Act and SBAP, and the impact it has on other adjacent semi-natural habitats/sites.

Appendix i. Staffordshire County Council Environmental Record Survey – 2012 The hatched area includes Plardiwick Farm, indicating the field is a former water-meadow.

Above and below: (33) A Nineteenth Century and (34) contemporary Ordnance Survey map used to show the extent of water-meadows along the Doley Brook.

16 ii. Aerial Photograph – 1963

This photograph shows the lower field at Plardiwick Farm as rough wet-grassland, virtually indistinct from the adjacent Doley Common SSSI.

It is likely that the field is part of the same peatland habitat complex as Doley Common, sharing the same post-glacial origin as one of the Meres and Mosses found in this part of the West Midlands.

Above: (35) Aerial photograph from 1963 showing Plardiwick Farm below the centre of the image.

17 iii. Aerial Photograph – 1971

This photograph (here in two sections) shows Plardiwick Farm with the lower field still as rough wet-grassland. It is dominated by the same fen vegetation that characterises the adjacent Doley Common SSSI.

It is likely that the field was drained and improved for more intensive grazing and cultivation later in this decade.

Above: (36) Aerial photograph from 1971 showing Plardiwick Farm.

18 iv. Photographs – July 2012

These photographs of the Plardiwick Farm pools were taken in July 2012. They show the whole valley flooded and pools underwater. This was five just months after the last clearance of the Doley Brook through The Acres by Gnosall Parish Council.

Above and below: (37) and (38) Views across to pools and flooding from Willy Lane. July 2012

Below: (39), (40) and (41) Sequence of panoramic views across to Plardiwick Farm. July 2012 Taken from the Holly Farm side, the images run looking from southern end of the farm to the north.

20 v. Copy of Email Outline of historical information regarding the Moor at Plardiwick; from Vince Smith (Chairman of Staffordshire Wildlife Trust) and local resident at Doleygate since 1996.

Subject: Doley Brook Date: 23/03/2015 Email From: Vince Smith

The flooded field, known locally as the Moor, 6 Acre Moor or 10 Acre Moor, at Plardiwick and adjacent to Doley Brook has a long history of flooding. I understand that when the previous tenant, John Hodgkinson, took on the tenancy of the farm the field was much as it is now. John made several attempts to improve the field, including by deep ploughing (the glacial erratics lining the farm drive are from the moor), re-seeding and liming. The last attempt was, I think, in the summer of 97 or 98.

The field has been subject to inundation from October through to Ma, certainly since 1996 in my own knowledge, and I think every winter when John has the tenancy. The current tenant has a near dry field in his first winter. This was an atypical event and was remarked on by John, who I understand, had warned the current tenant that the field would be unavailable for grazing until June and then only through to October. The start and end months of flooding in the winter period are approximate, but typically not more than a month later/earlier respectively.

The area should be considered contiguous with Doley Common in terms of the glacial origins of the landform and peaty soils. The field is of considerable ornithological interest, and in recent years has supported 4 species of breeding waders (lapwing, redshank, snipe and curlew), as well as numerous wintering ducks (typically teal, widgeon, gadwall and mallard). Passage birds of interest include black-tailed godwits, little egret, marsh harrier and peregrine. In summer the field is a hunting ground for barn owls and the ditches possibly held breeding garganey one year. I understand it once held a black-headed gullery.

The moving of the playing field at the sport and social club towards the moor a few years ago may have potentially increased disturbance of the site. Changes in land ownership and how fields nearby are farmed and used may also have contributed to disturbance or a reduction in the wildlife interest of the shallow valley. Upstream at the top of the watershed, the farm at Knightley is now a strawberry farm. It would be interesting to understand the run-off rates of water from the land and poly tunnels. As a casual observation I think it is now faster and more than it used to be and if there is more water held in the valley of the Doley Brook then farming practices upstream have to be considered.

My own view is that the fall in the brook is slight and a deepening of the brook at the Acres on its own wouldn’t be particularly helpful to the alleviation of flooding on the moor unless much more work was done in the watershed, both upstream and downstream.

The recent report on the hydrology of the SSSI for Natural England shows that understanding the hydrology of the valley is far from straight forward. I would support the moor and adjacent land being put in to HLS or other suitable scheme. The moor, in my view, should be seen as a floodplain and used to retain winter water, as it has historically and still does. It should be an SBI if not added as an extension to the SSSI. Other land around SSSI should also be brought in to a measure of notification.

I would guess the main issue for SCC is to maximise its rent for the farm whereas the farmer objects to paying rent for a field he can’t use as he might wish. Both therefore want it drained. I would counter those positions with the fact that the field has always been very wet or inundated over many, many years in living memory. The land is historically a lake/fen/marsh with glacial origins and they are trying to make something from it that it isn’t and has never been. Past attempts to improve or drain the land have failed and we should therefore be more accepting of its value as a wildlife site important in its own right and as part of the wider wildlife value of Doley Common and the rest of the upper Doley Brook valley.

In the past I have lodged reports for Doley with Craig Slawson at the Staffordshire Ecological Record Centre (SER) and they will detail quite a bit of information in respect of flooding and the wildlife on the Moor and around Doley, especially in the mid to late 90s.

21 vi. Flood Risk Assessment – from the 2015 Gnosall Neigbourhood Plan The Plardiwick field is indicated as high risk from surface flooding – at even higher risk than much of The Acres and Doley Common SSSI.

Above: (42) Gnosall Flood Risk Assessment Map 2014