Morning has broken like the first morning
Blackbird has spoken like the first bird
Praise for the singing
Praise for the morning
Praise for them springing fresh from the world
Sweet the rain’s new fall, sunlit from heaven
Like the first dewfall on the first grass
Praise for the sweetness of the wet garden
Sprung in completeness where his feet pass
Mine is the sunlight
Mine is the morning
Born of the one light Eden saw play
Praise with elation, praise ev’ry morning
God’s recreation of the new day
There is something very special about the English countryside, her light, her seasons, the riot of colour in spring, the buzz of bees and birdsong in summer, the little creatures that dart in and out of reeds, to and froing in those secret places only they know, the browns of autumn and death in winter followed by a resurrection in life eternal.
Headington, with its eternal traffic jams, industrial scale buildings and constant bustle of the busy, is yet blessed with the Lye Valley, for whom this song could have been written.
Ablaze with colour, dripping with life, the complex, fragile secret “wet garden” of the Lye Fen yet survives not yards from the hell we have created for ourselves, largely due to the efforts of the Friends of Lye Valley who work tirelessly for its preservation and improvement.
Eleanor Farjeon’s hymn is redolent with the imagery of water, speaking to the Lye Fen – formed of, and critically dependent on, the tiny springs who weep from her sides, collected of the rain and dew that nourishes it from above – it is used at children’s services due its beauty, and funerals for its rich allusions to the resurrection and rebirth, it is hoped we will not need to sing it as a funeral dirge as the bulldozers move in, from the Lye Valley broadwalk.
This precious gift is of national importance, of which we citizens are the keepers, is under mortal danger from one of the most reckless and irresponsible developments ever undertaken which will be commencing in the very near future.
This precious “wet garden” deserves our love, respect, nurturing and care to help it survive and thrive in a hostile urban environment, not brutal deprivation of its very lifeblood.
In the previous blog: Warren Crescent – A Study In Shame
The author spoke of the need to save the footpath running on the top of its slope, but it is very clear the long-held position of the Friends Of Lye Valley, (FOLV) that this development will risk the fragile ecology of the Lye, and could result in its destruction, are very well founded indeed.
The objection Summary is presented first, followed by more detail, feel free to read the background after the Objection Summary and then return if not familiar with the issue.
REFs, eg: Pre-EIA, are given in full in the Reference section below.
Oxford City Council has granted itself planning permission as below for 10 houses:
13/01555/CT3 | Erection of 10 x 3-bed dwellings (use class C3) together with associated car parking, cycle and bin storage. Diversion of public footpath. (Amended plans and description) | Land East Of Warren Crescent Oxford Oxfordshire OX3 7NQ
The Development Site
The planned development and its context can be seen below:
The Lye Fen – A Quick View
The tiny Lye Fen is critically dependent not only on the quantity, and in particular the exact chemical composition of its groundwater, it is one of the rarest habitats in Britain so NO RISK can be tolerated to it, it is unacceptable to risk the loss one single species in this isolated, ice age fen, we must protect the environment entrusted to us.
Even now, species that have not been recorded for decades may yet spring from dormant seeds, particularly in the western fen where remediation is ongoing, fed by two primary Tufa springs approximately 7-8m from the development site.
As stated clearly in the Council’s own Site Policy – the test mandated in SP60 is very simply:
Planning permission will only be granted ….if it can be proven that there would be no adverse impact upon surface and groundwater flow and the Lye Valley SSSI
THIS TEST CAN NOT BE MET, THE DEVELOPMENT CAN NOT PROCEED
- No consideration of the effects on the groundwater flows from the wider catchment of 1000s of tons of foundations placed directly above upstream and across the groundwater flows to the western fen was ever done, hydrological reports examined only the hydrology of the site itself pre build, this is critically important and renders Natural England’s assent invalid and may lead to the loss of the western fen, approximately 50% of the SSSI
- The Development Site is a hydrological focal point of all above flows to the Western Fen
- The mandatory Geotechnical Design Report (GDR, Eurocode 7) was never undertaken (REF WSP Base), which would have confirmed the site suitability
- The policy requires a buffer zone with the SSSI, yet every single part of the site will be disturbed as shown below
- An EIA (Environment Impact Assessment) was not conducted although clearly necessary due to the site’s location both proximate and upstream of the SSSI and the habitat, the OCC chose not to conduct one
- Planning permission, and the subsequent approvals, particularly by Natural England, were not validly granted as critical information, namely that the site was composed of contaminated, made ground, was not presented to the East Area Planning Committee (Sept 2013) although a detailed report had been received in June 2013 (Land Quality Assessment), when finally presented in 2016 it was addressed as a building control matter, not as a very substantial increased risk to the Lye
- The Council ignored its own advice to restrict building in groundwater catchment areas of the Lye
- Apparently incorrect advice given to the Council that the Sand Member geological layer did not contribute to the calcification when it clearly has substantial limestone content
- Ignored the need to protect the Lye from climate change by protecting groundwater which is more constant than surface water and directly feeds the fen
- The consequential risks to the Lye Fen were therefore not communicated
- Expert advice appears contradictory or incomplete presenting a clear risk
- This project, even based on current knowledge, has been extraordinarily expensive and will be an order of magnitude more if allowed to proceed, there is a desperate need for housing in Oxford and the resources squandered on this project could deliver say 40 houses on at a cheaper location – this is costing homes, and alives – in effect more housing can be built elsewhere more cheaply with less consequences to the environment and less negative impacts on green space deprived communities
- Removal and relaying of the soil and sewage pipes which which service the much of the Town Furze estate (See The Slope below) are 4 metres underground on the natural slope and replacement to modern standards will be prohibitively expensive and will result in sewage and drainage outages for residents.
- If this project is not stopped there is a strong possibility of issue discovery causing unacceptable outcomes, as in effect, it will be too late to stop
- The conditions set for planning permission, particular that the site is fit for its proposed use (Condition 26, Phase 3) – CAN NOT be discharged
The site is on contaminated made ground (tipped embankment) consisting of contaminated builder’s rubble, which is unstable and unsuitable to be built on, terminating in an artificial, steep slope forming the Lye Valley .(approx 32 to 42 degrees) over a now buried natural slope of 23 degrees which itself consists of poor quality limestone and sand.
The evidence that natural ground falls approximately 2-4m under the intended houses (map 1954) consisting of made ground then to poor quality rock below the housing has been available to OCC since 1954, and is on its own Planning Portal under Town Furze Estate, and also via BGS surveys (1973) which show drops of up to 5.5m – it is simply beyond comprehension that it has paid for three partial surveys, run this project for 13 years when the development is not just undesirable, but WILL BE VERY EXPENSIVE TO DELIVER. In addition, it should have been immediately obvious that a housing gap like this was for a reason, of all the green spaces in the original estate only this one is NOT marked children’s playground, the others all now built on. (see earlier blog) the lack of common sense shown by the Council is hard to comprehend.
This means very deep foundations (possibly 4-5m (1.8m + 2m made ground + extra support on soft strata) and excavations will therefore be required as:
- The made ground (05m -3.5m/West->East) cannot support foundations
- The layer below (Beckley Sand Member) it is of poor quality rock and probably with poor load bearing capabilities
- The underlying, natural, buried, steep slope will require additional extra support for buildings
- Huge quantities of soil/rock will need to be removed causing instability or collapse of the artificial bank, disturbance of contaminated soil and pollution of the Fen
- Heavy equipment cannot be supported, so much more made ground will removed to reach a load bearing surface
Earthmoving equipment cannot operate without substantial further excavations, clearance and support.
Building materials such as highly alkaline concrete may damage the critical PH of underground water flows
The consequences of this are that the underground North/South flows from the wider surrounding catchment which directly feed the springs/seepage line of the Western Fen only 5m away, in particular two principal springs 6-7m away, will be subjected to intense pressure from the weight of the development approximately 1-2m directly above in addition to the disturbance of the building phase.
Natural England would have assumed foundations of 1.8m, not 4m, and on solid, not made, ground, this increased risk was never communicated, therefore Natural England’s assent was not valid as it was purely based on incomplete and incorrect evidence supplied by Oxford City Council.
The contaminated nature of the tipped embankment means:
- Further evacuations of at least 1m depth up to the edge of the artificial slope are required, to replace the topsoil in the gardens to reduce cancer risks due to Polycyclic Hydrocarbons (PAH), with a geotextile membrane below
- The identified contaminants notably PAHs will be released into the Lye fen
There is a clear health and safety risk to workers as:
- The hidden, steeply sloping nature of the site means a risk of accidents from equipment on soft ground
- Exposure to PAHs and potential asbestos coming from the tipped embankment consisting of pre 1960s builders rubble, it does not appear a through test for asbestos has been conducted although there is aa clear risk
To mitigate house rainwater runoff the Council will build a SUDS system, itself requiring yet another extensive excavation to approximately 3 metres below ground level for approximately 60 metres, it is unclear how this structure will be supported or built – this is situated 5m from the SSSI boundary and the Western Fen adjacent to the two main Tufa (Calcium) springs.
The SUDS system is unsatisfactory for the following main reasons:
- It requires maintenance in perpetuity, it is a fail-to-danger system
- No example of it working in this context has been supplied, it is experimental, to the contrary, an Oxfordshire example cited by Dr Webb has caused severe damage
- All run off from the development is deposited hundreds of metres further downstream, altering the hydrology
- The water will not acquire the required complex mineral and chemical composition, the argument the limestone of the SUDS will be a substitute seems very superficial , the argument advanced that current water flow is via the Sand Member is not beneficial to mineralisation is directly contradicted by the Council’s own evidence
- Water from the gardens will mostly be lost as it will sink to the geo textile membrane and be impeded at that point
- The houses will have greater water loss in drizzle
- The Made Ground currently buries most of former fen habitat, the area at the base may also be recovered using undiverted groundwater in the future
In summary, almost the entire site will be removed or disturbed to a depth of 3-4 metres both for building and access by heavy equipment, the large excavations required may result in weakening of the steep bank, release of pollutants in the Made Ground and from construction entering the Lye and/or PH changes, blockage of underground water flows from a large part of the surrounding catchment, and could cause collapse of the banks of the Lye during the building phase, in addition to irreparable damage to the Lye fen – the possibility of toxic alkaline concrete spills, or flooding in bad weather cannot be excluded.
The entire incised valley is approximately 390m long, the development is 190m of this, indicating the sheer scale of the proposed works.
Perhaps the Council can find some mitigations, or contradict some of the details here – however the overall assessment remains the same. The Council cannot discharge its own policy which is that damage must be proven not to occur.
This places the precious Lye Fen at great risk of a local environmental catastrophe – at best this is a high stakes gamble on one of the most precious environments in the UK – the risk of the loss of a SINGLE PLANT SPECIES is unacceptable – these are ice-age relict species now isolated by thousands of miles from their origins, existing in a tiny area of fen (0.5ha) of which only 19ha still exist in the UK, each similar, but each unique.
The geology that exists for the calcareous fen only extends to approximately just before the southern SSSI boundary where it becomes ferrous, the ONLY place the fen can exist is north to the head of Lye valley, habitat already partly destroyed by tipped embankments/made ground on both sides of the valley, making the western fen area particularly precious, this is a tiny isolated area.
IF the foundations do not damage the underground watercourses, IF the excavations do not undermine the bank and cause collapse, and IF the water chemistry is not altered, and IF there are not any chemical spills and IF there are no important water flows under the houses and IF climate change does not put increased pressure on the fen and IF all the reports from the Council are correct, then this will not cause irreversible and permanent damage to the Lye – this is FAR from the standard that damage must be PROVEN not to occur set by the Planning Inspector who demanded this wording, anything less is a contempt of her office.
The Council choses to ignore the concerns of experts with decades experience in the Lye Valley and its own previous reports, yet accept without question those commissioned for this development bringing into question its impartiality, it believes what it wants to believe not what it should.
It is incomprehensible that the Council did not look at its own 1954 Town Furze contour map, available on its own Planning Portal, of the site and conclude, without wasting hundreds of thousands of pounds, that the site was not deliverable, or only at very great cost – common sense would have dictated that the search be done both of this and the BGS (British Geological Survey) results for this site PRIOR to starting this project. Further, that the issue of Made Ground was either not presented to the Committees, with no indication of the severe consequences both the the environment and costings.
The Council should not be blundering about with such a fragile, sensitive and ancient environment when it doesn’t know what it is doing.
Part one of a further Land Quality Assessment Report dated June 2018 has been redacted, why?
The lack of green space in Headington, clearly documented in the Green Space Survey of 2007/2010 was also ignored.
In relation to the green space lost:
- The loss is unacceptable due to extreme green space shortage as documented in my earlier blog (see link above)
- Children will be forced to continue to play on the current polluted playground on The Slade
The Council is currently attempting to divert a footpath having failed to consult with the Ramblers, a statutory consultee, prior to the grant of planning permission in 2013
Detailed discussions about many of the topics discussed here can be found here, including the numerous conditions currently pending approval cannot be, or are not yet discharged as presented by the FOLV. (See below)
and my previous blog: Warren Crescent – A Study In Shame
A petition asking the Council to designate Warren Meadow as Local Green Space was conducted up to 15/11/2015, garnering over 800 signatures, many from experts, volunteers etc, over 80% from Headington with over half from the Town Furze Estate.
If after reading this article you do NOT believe, or consider it is possible, that the Council has discharged its own site policy requirement that :
Planning permission will only be granted for residential development at Warren Crescent if it can be proven that there would be no adverse impact upon surface and groundwater flow and the Lye Valley SSSI. Development proposals should be accompanied by an assessment of groundwater and surface water. (SP6O)
Write to your City Councillors expressing your deep concern at the issues raised, if you are a member of a group ask the members to write too and engage it, RT Twitter communications, tell your friends.
STOP THIS BEFORE IRREVERSIBLE ENVIRONMENTAL DAMAGE MAY BE DONE
A number of key issues concerning this development documented here have never been adequately addressed which clearly indicate this cannot proceed, it must accept that the numerous planning conditions which must be discharged prior to commencement simply cannot be, and this reckless scheme must be abandoned.
The planning conditions currently under review CAN NOT be discharged, the objections to these an be summarised here FOLVFOLV.
The Lye Valley runs from The Slade down to Cowley as shown below, it is comprised of a LNR (Local Nature Reserve) and further down, the SSSI (Site of Special Scientific Interest)
A very good overview sketch by Dr Judy Webb can be seen here:
Note the proximity of the SSSI and the Local Nature Reserve to the development site.
Its ecological importance of the SSSI can be summarised by the following statements by Natural England:
Lye Valley is one of the best recorded examples of a calcareous valley fen in southern England, a nationally rare and threatened habitat which is virtually confined to parts of Oxfordshire, East Anglia and North Wales.
The area has been studied by botanists since the 17thcentury and aroused particular interest during Victorian times. Over 300 species of vascular plants have been recorded at different periods, including many which are strongly associated with calcareous fens and are uncommon in southern Britain, although several have not been recorded for many years.
The SSSI consists of two areas of open calcareous fen situated in a shallow valley drained by the Lye Brook, close to the centre of Oxford. The total area of wetland vegetation has changed dramatically this century due to infilling at the northern end of the valley, landscaping of a golf course to the west and construction of houses and gardens (many of which still contain remnants of fen habitat) to the east. Hydrological studies suggest that these modifications have increased water run-off and led to erosion of the stream channel, also altering conditions locally within the fen areas.
The fens are supplied predominantly from the lateral movement of water percolating through base-rich Corrallian Beds; spring and seepage lines occur where freely-draining calcareous grits and sands meet the impervious Oxford Clay. Under these conditions a base-rich peat up to 1.5 metres thick has been laid down along parts of the valley.
A study of preserved pollen, macroscopic plant remains and molluscs has shown how there was a succession from open water to reed swamp, which existed for about 500 years until the peat built up to form a fen. Due to alkaline ground-water there has been no development to acid bog.
Flush and spring fen
Groundwater sometimes breaks out on the surface, either via gentle seepages, which give rise to flushes, or through greater flows that are evident as springs. Groundwater is rich in dissolved minerals, picked up during its passage through soils and rocks.The resulting water chemistry and degree of flow at the point where groundwater breaks out determine the type of plants and animals that occur in and around springs and flushes. The greatest contrast in the types of flush and spring fens that develop around groundwater seepages is between those arising from chalk or limestone rocks and those on quartzite or granite.
Mosses, liverworts, sedges and rushes are common and often predominant plant species in flush and spring fens and several species of orchid are also associated with these communities. Flush and spring fen may also be a component of other types of fen, such as valley mire and basin mire.
The maintenance of the characteristic composition and diversity of flush and spring fens is dependent on a number of factors operating both at the surface and below ground. The quantity and quality of the groundwater must be maintained, though the quantity is not likely to be naturally constant throughout the seasons or between wet and dry years.
The groundwater comes from aquifers, and these may become depleted due to abstraction or failure to recharge.They may be contaminated by agricultural chemicals such as fertilisers, or by pollution leaking from landfill sites. When this has occurred, the characteristic sward of short herbs and mosses will be replaced by rank grasses, reeds and nettles. Changes in flush and spring vegetation as a result of changes in the quality and quantity of the groundwater that feeds them are important indicators of the condition of the groundwater aquifer.
Apart from a thin scattering of well-rotted farmyard manure, fertiliser, lime, pesticides and herbicides should only be used down slope of the flush or spring, and should be kept clear of any wetland fed by them.
Natural England designates this a “recovering” ecosystem, following a status of declining in 2006.
The Made Ground was formed at some time in the 1960s using builder’s or construction rubble from another, unknown source. It comprises of grit, bricks, bitumen and other materials, of which asbestos cannot be excluded.
The above diagram (repeated also under Hydrology) shows a to-scale cross section of the development at its narrowest point – the surface is level at 95m, but there is made ground – contaminated, loose builders rubble, extending down from 0.5m to approximately (west) 4 metres above the RED diagonal line forming the artificial steep slope to the Lye immediately below (east) – as discussed below in the The Slope section, this much steeper, and deeper, at the southern end of the development.
The aquifer is loose rock through which water currently trickles, mostly towards the viewer is in this diagram.
The WEST FEN shown in green is NOT fen at the location shown here but simply scrub, but is representative of the western sloping fen very slightly further down the valley, which is on a shallower angle. This section would have been fen before the tipped embankment was formed.
BGS surveys (1973) have shown made ground depths of up to 5.5m at a borehole only 2m from the intended housing, the patchy sampling for this development has shown depths up to 3.5m with many “dark areas” unsurveyed, WS104, close to this was a shallow bore hole.
The steep nature of the hidden natural slope means that very small differences in location can have great differences in depths.
Below this is poor quality rock (not shown) either Wheatley Limestone Member (only to west):
Gravel size fragments of limestone in a yellowish brown and grey slightly sandy clay matrix locally underlining by very closely to closely fractured shelly limestone.
Or the Beckley Sand Member aquifer (majority):
Orange/yellow brown sand. Thin beds of weak and very weak limestone and/or gravel size fragments of limestone were locally encountered within the strata.
Both of which may not support housing or compact, blocking the aquifer flows below.
The black descending lines show pile foundations to 4m as at least 2m of solid ground is required below the made ground (below the red line), house foundations are normally 1.8m deep. Assurances have been received these will not be used, but traditional strip/pad foundations will, even if feasible, need to be as deep and be even less permeable than piles, to accommodate for the the underlying slope, and the rock quality poor, even deeper foundations may be required.
The exact nature and depth of the foundations has not been supplied via an FOI , but this would be a difference in degree, not kind. Structures marked on the plan in the gardens will require foundations (unknown)
Data is taken from the boreholes marked above, Council reports and contour maps of the land as it was prior to the tipped embankment, it concurs well with the Council report diagram in Warren Crescent,Technical Note Ecology, SUDS and Groundwater Quality 2015 (PBA Final) (REF: PBA Final)
The water table is level at 89m at this point, many springs seep out at this level from the aquifer, the Lye Fen is at 86m, other sources place it at approximately 91m-93m.
The purple area beneath the ground shows conservatively the area of land disturbed, for the generally for any excavation required, the rule of thumb is it should be three times larger.
The grey patch between the house and the steep slope is the clean, new layer required to prevent carcinogens (PAHs) poisoning the residents. A geotextile membrane is planned below this which will further impede water flows.
In reference to the diagram below:
The diagram shows the excavation areas (Purple/SUDS,Red/Garden/Blue/Houses), huge amounts of earth will be abstracted and replaced by concrete, highly alkaline, which could impact on the delicate PH balances the fen depends on.
The red shows the garden area, 1-2m will be dug out here, in addition to the water blocking geotextile membrane below: (REF: WSP LQA Part 2, p1)
It is recommended that the following is implemented into the development:
Removal of Made Ground or a clean cover layer should be incorporated into proposed garden areas. A suitable depth of clean cover soil is to be agreed with the Local Authority.
A geotextile membrane or hard to dig layer should be used as a break layer to prevent Made Ground mixing with the clean topsoil. Excavated Made ground may be placed under areas of hardstanding (i.e. building footprint) as an alternative to off-site disposal.
Made Ground is not considered to be a suitable medium for residential garden areas. A thickness of clean cover (depth to be agreed by the Council) will need to be incorporated and provide suitable medium for planting. This may require the removal and replacement of Made Ground to meet levels. A geotextile membrane or hard to dig layer should be used as a break layer to prevent Made Ground mixing with the clean topsoil.
Critically, water flows through the land will in effect met an impermeable barrier at the foundations or by the compression of the underlying strata. These have been determined to be southerly where sampled, but may vary locally and reports broadly but not entirely concur:
This will deprive the Lye not only not of the water falling on the the development (which will be retrieved by SUDS) but possibly ALL water flowing from the surrounding land as indicated by the blue arrows above.
The natural land with a steep drop, over which the houses will be built is shown here (REF: Town Furze Estate Map, 1954), showing that depths (feet on map) steeper in parts than the patchy sampling so far done (max 3.5m of made ground).
The actual housing estate plan is overlaid below firstly with the development outline, so the underlying contours can be seen, then the development details with the stormwater and soil pipes.
Contours are highlighted in YELLOW, with heights in feet (map). Houses and SUDS outline in BLUE, the site (including gardens) in RED. BGS (British Geological Sampling) sampling locations and depth of made ground found are marked by a black round dots – the deepest, very close to the development, found 5.5m of made ground.
The presence of existing sewage and surface water pipes serving most of the Town Furze estate can be seen in purple below:
Conclusions – Topology
- There is are drops of 2-3m to even reach the natural surface drop at the steepest point of the development, approximately at the last house from the south of the end of the housing block with 3.5m at least in other parts (map) mostly confirmed by the BGS points above.
- The natural slope becomes steeper going south to the approximate location of the BGS survey point, it then becomes more shallow forming the side of a very small side valley – the contours at the SUDS are unknown.
- The pipes run directly under the development and must be moved as it is not permitted to place new buildings directly of sewers/waste water pipes, further they are very probably lying on the natural slope metres underground – this will VERY expensive to remediate.
Both the eastern and western Fens (Development side) primarily receive the groundwater they need from springs and seepages above the Lye itself as shown for the western fen (under threat) below:
This is a “perched water table” with groundwater mixing with the limestone in the Beckley Sand Member aquifer at approximately 89m AOD and associated limestone layers as it travels alongside and slightly converging the Lye mostly parallel (North-South (REF: WSP LQA) or NE-SW (REF: Pre-EIA, Fig. 4), flowing above the level of the Lye.
Reports commissioned by the Council (WSP Base) stated the perched water table did not exist, contradicting evidence by the Pre-EIA report, without providing any clear evidence, the observed springline 3m above the Lye alone contradicts this as does the observations of the Environmental Agency and the Pre-EIA report.
The seepage is mostly a constant flow and weeps out of the valley sides, at approx 89m or 3m above the Lye, at the central part of the site, with levels dropping going down the valley, borehole sampling has shown this to be very consistent across the site at 89m, this report broadly, but not exactly, concurs, placing the water table slightly higher:
Groundwater levels were measured between about 4.9 and 5.5 m below ground level, corresponding to reduced levels between about 90.0 and 89.5 m AOD. The groundwater levels fall from northwest to the southeast towards the valley of the Lye Brook (Peter Brett)
These layers are flaky, grit, apparently of low density, it is this, possibly with fissures, that allows the groundwater to mix on its long underground journey with minerals needed to ensure the fen’s survival – it is reasonable to assume this process is complex and reliant on many factors, including the exact density and composition of the geology it flows through.
Different strata have different resistance to water flows (hydraulic conductivity) meaning one or two water tables may be a simplification – the flow of groundwater from a seepage line at 89m indicates that most water flows occur above this level.
What Damage Could The Development Do?
The presence of perched water table, or equivalent, is confirmed by the Pre-EIA report, and by seepages occurring 3 metres above the Lye, meaning that effects of compression will be VERY severe indeed, compressing thin strata only slightly below ground level.
Even if there were one water table extending down to the level of the Lye, as suggested by WSP Base (without clear evidence) this would still be severe.
The following diagrams pre/post development show the importance of the development site which is a focal point for ALL flows to the western fen from the entire western catchment.
This is confirmed by the findings shown in the WSP report, Graph C-2 which shows the groundwater levels rising HIGHER than the amount of rain falling, which could only occur if flows are concentrated at that point. Southerly flows of water are confirmed in all surveys.
Prior to the development, flows concentrate at the development site, post development, the crushing effects of foundations on delicate aquifers means water could be diverted away.
The below shows in black outline the catchment area, brown shows the potential catchment area (REF Pre EIA Report) for the Lye – flows are either north – south (Various), or NE-SW (Pre-EIA) so the development could have a disproportionate effect on the Fen as flows converge at the Lye.
The following diagrams (pre/post) shows the development site in vertical section, firstly prior to any development or tipped embankment, when the fen would have extended further north and up the Lye valley from the current western fen limit, prior to the tipped embankment impeding the flows and covering the land. (RED)
Groundwater would have seeped out to the now lost northern western fen.
The following vertical section shows the development (stretching 120m away from the viewer) bearing down on the strata that prevent the water simply being lost – the result if compression and compaction is that the perched water table is lost, and the western fen dies.
Water flow here, and the western fen, is towards the viewer.
The current flows can be seen below – rainfall lands on the current made ground surface, flows down to the 89m level and emerges at the springs at the edge of the SSSI in a N/S (right to left) direction, which will vary according to the slope and geology of the natural ground, picking up calcium from the sand member, as can be seen – the western fen is critically dependent on both this flow, and the exact mineral content as shown below, and is located only 5m away:
This shows the same with a North/South section:
The intended development may compress or disturb this directly above the principal flow from a large part of the catchment. NO report has been done on the effects of placing 100s of tons of weight 1-3m directly above it, this is particularly important with a perched water table.
The changes this development could produce locally are shown below:
The rainwater from the development itself will be sent to the SUDS system, under the development will be a disturbance both of the made ground and layers underneath by compression, which will require considerable excavation due the underground slope and poor nature of the geology (sand member)
This study (REF: Pre-EIA Assessment) has concluded that the size of the groundwater catchment areas of the Lye Valley and Boundary Brooks have been reduced considerably by the surrounding urban developments. The groundwater catchment for Lye Valley North SSSI is considerably larger than that of the South SSSI. Therefore, it is very important that the size of the groundwater catchment zone for the South fen is not reduced especially in the light of predicted UK climate changes over the next 30 to 50 years.
Likewise, the nature of the surface water catchments have been altered by urban development and have increased rates of erosion within both the Lye and Boundary Brooks causing damage to the SSSI and to the SLINC areas.
Groundwater protection zones are not fully mitigated by the use of SUDS therefore development within these areas must be restricted or eliminated.
It recommended the setup of Groundwater Protection Zones to corresponding approximately to the below diagram, recommending development should be restricted or eliminated.
A number of statements were made (REF: PBA Final) as presented to the Planning Review Committee:
Assertion: The principal area of fen is the eastern side which does not receive water from the western side due to incision by the Lye
Both the west and eastern side are designated as part of the SSSI, the western side, at the time of the report, was reeds, but is now recovering and has exactly the same value as the eastern fen in terms of conservation yet is metres from the development and directly impacted by it. The eastern fen is no more or less principal than the western fen.
The report is now out of date, the description of it as “a southern area of cleared reeds” belies its importance, although the restoration is addressed briefly.
The lack of interaction with the main Lye stream for both fens is mostly due to the Thames Water Surface Water/Storm Drain causing severe incision of the stream bed, creating a vertical gap and leading to drying of the adjacent fen or “the evil drain”, not a normal state.
It true that the primary source of the eastern fen is the springs above (as also the western fens), but water levels, particularly with ongoing remediation, can help slow the loss of water, even if not directly used, by delaying the time it takes groundwater to percolate through a saturated fen as opposed to one 1m above to the spring level, which is deeply incised due to the effects of stormwater artificially directed into the river.
Assertion: Use of SUDS would not decrease the mineral content in groundwater as the development would be above the Beckley Sand Member which has little mineral content
The sands were often calcareous and contained shells. The Beckley Sand Member comprised bands/doggers of grey limestone (varying in thickness) generally throughout.
In addition, almost every single borehole log shows that the Beckley Sand Member has very substantial limestone content, interspersed with limestone layers, a fundamental error was made in assuming that the “Sand Member” was formed mostly of sand.
Although the presence of limestone is acknowledged, it appears to be underestimated:
current site is underlain by made ground which is composed of non-limestone materials which are themselves underlain by the Beckley Sand (predominately a siliceous sand with localised beds of limestone)
This claim is further contradicted by the Council’s own report (REF: Pre-EIA) which states:
The Lye and Boundary Brooks are fed in part from a series of springs originating from the calcareous sands and sandstones of the Beckley Sand geology.
Fenland depends on a constant flow of ‘base rich’ groundwaters with high concentrations of 50 to 300 mg/l calcium balanced by hydrogen carbonate (or bicarbonate), dissolved carbon dioxide and sulphate (Hájek, 2002). Magnesium and calcium have similar chemistries and magnesium is often included in the calcium analysis! The concentration of calcium depends on the partial pressure of carbon dioxide and the sulphate concentration in the calcareous geology of the aquifer.
The proposed remedy is that the limestone in the SUDS system would compensate, but this seems, again, an oversimplification, similar to removing a complex centuries old soil and then mixing sand and fertiliser and expecting the same quality – in addition to being in essence experimental.
There is a delicate balance of water seeping through the Beckley Sand Member and that gradually seeping through the much less pervious layers at 86m and/or flowing down the Lye
In summary, the PBA report had the following critical deficiencies:
- It failed, mostly, to acknowledge that the western fen habitat had the same protections and value as the SSSI, even if it was degraded at that time
- Did not consider the catchment flows, other than to state they were not relevent as they would only affect the western fen
- Referred only to the rainwater deflected by the SUDS system
No Geotechnical Design Report (Eurocode 7) which assesses strength, stability, serviceability and durability of structures has ever been undertaken – this would not have addressed the hydrology per se, but may have indicated the effects on the underlying strata, this is an identified limitation of the WSP LQA Part 2.
Surface water flows
The water flow in the Lye Brook is not the main source of wetness in the fen (main source is groundwater fed springs) however erosion of the bed of the Lye Brook from road surface run-off entering at the head of the valley from the “evil drain” has been a problem for the fen near the brook. Severe erosion deepened the brook bed which has caused drying of the fen adjacent.
Surfacewater lacks the chemical composition the fen requires and highly polluted although the fen relies on groundwater seepage, surface water contributes by keeping the water table higher.
The Lye, and its groundwater, must be protected from climate change as per the Pre-EIA Assessment, Southfield:
Data from the UKCIP program using the medium high emission scenario indicate climate change driven precipitation changes will cause an annual 10% reduction in rainfall by 2020. Summer rainfall will be 30% down by 2050 and 40 to 50% down by 2080 (UKCIP, 2002). The consequences of a changing rainfall pattern to the health of the fen areas and spring zones is difficult to estimate.
Therefore, it is very important that the size of the groundwater catchment zone is not reduced and that run-off from the urban catchment is diverted away from the Lye and Boundary Brooks.
This development may impact on either the quantity or quality of groundwater reaching the Lye fen, these effects may not be visible for decades after a harmful change has been introduced.
Policy and Procedure – How Did It Go So Wrong?
The site policy SP60 states it must be PROVEN that the development will not cause harm, yet the Planning Officer report to the Planning Committee of 4th Sept 2013 which led to approval stated there was “little possibility” that there would be harm in the report to the Planning Committee on which:
- Does not met the test set
- Appears unbacked by any evidence available
Why Wasn’t A Search Done Of Existing Evidence?
Incomprehensible, a stated above.
Why Was No EIA Assessment Done?
This development is a schedule 2 development that may require an assessment if it falls into the categories below:
- Major developments which are of more than local importance;
- Developments which are proposed for particularly environmentally sensitive or vulnerable locations; or
- Developments with unusually complex and potentially hazardous environmental effects
It is extremely difficult to understand why, as the development fell into all three categories, EIA screening was not done.
The Council determined that:
The Proposed Development will utilise traditional strip/pad footings founded on the underlying natural strata below the made ground and will not therefore impact the existing groundwater flow regime. The drainage strategy mimics the existing greenfield drainage regime
Apparently, exavating an area 190m * 10m * 3-4m deep, 5m from a SSSI, upstream of one of the most isolated and rare fens in England on a tipped embankment directly above, and forming, the valley was not considered worthy of even a EIA screening test
Two ground investigation reports of 27thJune 2012 and Dec 2012 identified Made Ground, and specifically the need for deeper than usual foundations – yet NO mention of this was made in the final Planning report to the Committee on the 4th Sept 2013.
The failure to present such critical information to the Committee is frankly inexplicable and requires formal investigation.
The EAPC Committee (with only six of the nine of the regular members present) deferred its decision pending further information regarding the SUDS system (among others) but the proposed SUDS system, although important only affects runoff from the houses NOT the underlying hydrology on which the fen depends.
Many subsequent reports document the ground conditions, SUDS design and many other factors, but this are mostly statements of fact, not judgements as to whether this is completely safe.
Based on the incomplete evidence Natural England as a statutory consultee stated in 2013:
- No objections to the application. There should not be a significant impact on the hydrology of Lye Valley SSSI, provided that the design and construction methodologies proposed in the application are implemented.
- There will be a need for the Sustainable Urban Drainage Scheme to be maintained in perpetuity, and restrictive covenants need to be put in place to ensure that the block paving and grass gardens are maintained as they have been designed and the dwellings cannot be altered should the housing be sold in the future.
Following the review of the SUDS, NE stated it was satisfied with the outcome which only addressed the SUDS system, but the discharge of the conditions in red above cannot be met.
Here we see the first of many echos in the echo chamber that the communications represented, OCC asking for the opinion of Natural England, NE relying on the reports (only those commissioned for the development) and then setting a target, OCC stating that NE did not have any objection, which in turn was based on the OCC reports.
but critically, nowhere in any of the documentation is there any clear statement regarding either of which streams or flows run underneath the development, or the effect of compression/compaction and abstraction of soil will be – this could form in effect an underground barrier 100s of metres long for ALL flows into the Lye, broadly across its south, south easterly flow.
As no design for foundations has been presented, no quantification of effect can be derived, and even should such a report be produced, it could never eliminate risk, therefore this scheme must be abandoned, it cannot be PROVED that no damage to the fen will occur.
The EAPC deferred the decision:
The Committee wished to concentrate solely on these three outstanding issues when the proposal is reconsidered at a future meeting, it being satisfied that the scheme met other requirements and issues from the planning officer report.
which, of course, omitted the key facts, although known.
It is very probable that had the Committee been made aware of this the decision would have been an immediate refusal, or at least until suitable planning conditions could be formulated.
The application, subsequent to approval by the EAPC on the 3rd March 2016, was again called in by no fewer than 13 councillors – then came before the Planning Review Committee on the 30th March 2016 and was approved.
The only new piece of evidence presented was the Technical Note Ecology, SUDS and Groundwater Quality 2015 (REF: PBA Final) commissioned specifically to address the hydrology concerns raised by the FOLV as discussed above, and the issue of made ground, (see above for issues), the serious issues regarding the scope and conclusions are presented above in Hydrology.
In addition, finally, after 13 years (2003-2016), the issue of Made Ground was raised due to the concerns expressed by the FOLV, residents and one Councillor.
The Committee expressed concerns about the stability of the housing development site as it was known to be on “made ground”. The developer gave assurances that this had been addressed in the technical proposals and that the houses were located where the “made ground” was most shallow and the loading of the houses would be through to the natural ground. The planning officer confirmed that this would be a matter for Building Control and that the properties would not receive completion certificates if they did not comply with building regulations.
bizarrely, the Officer was simply stating that Building Control would ensure the houses were safe, which is a given anyway, and did not address the effects this would have on the Lye, or the possibility the development was undeliverable.
Assurances were given the issue had been addressed in the technical proposals although only some of the site had been surveyed, neither have these ever been published or formally assessed.
A key statement made by the Natural England representative at another meeting was that the existing tower blocks to the east of the development had not caused any groundwater issue, therefore this development would not either – which was not only a unscientific supposition without any evidence, but further, the underwater flows are north-south, the tower blocks are to the east of the Western Fen.
Requests were made to defer until Natural England could comment and further studies made, this was rejected.
The Planning Conditions
NO PLANNING CONDITION was imposed to provide a plan that the development could be built without risk of significant environmental damage, either during or after construction – nor indeed to provide for the extremely dangerous conditions that would be faced by the workers operating heavy equipment on soft ground on hidden steep slopes.
The Committee was therefore misled by omission of key facts pertaining to the execution and effect of the development.
The very serious environmental, financial, and technical ramifications of the Made Ground were glossed over, although they were the most serious issue facing the development, that brought the very feasibility into question.
Currently, at time of writing, a number of submissions seeking to discharge the conditions have been submitted, but not yet discharged these are very well summarised in an email from Dr Judy Webb, Chairman of the Friends of Lye Valley – Email to Project Manager from Dr Judy Webb
Particular attention is drawn to Condition 26 (Phase 3) currently undischarged:
26 Prior to the commencement of the development a phased risk assessment shall be carried out…
A Phase 1 has already been undertaken and has identified the potential for contamination to exist on the site. A phase 2 shall be undertaken and shall include: a comprehensive intrusive investigation in order to characterise the type, nature and extent of contamination present, the risks to receptors and to inform the remediation strategy proposals.
Phase 3 requires that a scheme of remediation and/or monitoring to ensure the site is suitable for its proposed use be submitted and approved in writing by the LPA. The remediation shall be carried out in accordance with the approved scheme and the applicant shall provide written verification to that effect.
The development shall not be occupied until any approved remedial works, have been carried out and a full validation report has been submitted and approved to the satisfaction of LPA.
Reason- To ensure that any ground and water contamination is identified and adequately addressed to ensure the safety of the development, the environment and to ensure the site is suitable for the proposed use.
The condition is poorly drafted, but then intent is clear – to ascertain the risks the development poses and to ensure the site is suitable for proposed use, and it will not damage the environment. Specifically, it discusses contamination, but logically ALL risks must be identified and remediated.
One sample discovered PCAH (carcinogen):
Locally elevated PAH and TPH was noted in the soils but contaminant concentrations in the soils tested were below the applied assessment values for a residential land use with plant uptake.
Risks to Future Site Users: Given the nature of the proposed development, the risks to future site users are low to moderate.
Builders rubble is by nature very varied, it may contain high levels of PCAH in a patch of old road or asbestos in an old roof.
No asbestos was found, but the report makes this clear it is not a formal test for asbestos.
No assessment has been done of possible contamination of materials that will be introduced into the site by laying of driveways, highly alkaline concrete foundations etc.
Condition 26, Phase 3 cannot be discharged for all the reasons given above, note although it specifically mentions ground and water contamination, the last phrase highlighted is a GENERAL condition, namely, the site is suitable for its proposed use, clearly it is not, the developer has not yet even submitted a discharge report, and the Phase 1 report has been redacted.
The above indicates this development is reckless, and risks damaging one of the rarest habitats in England, the Council cannot meet its own test that it can be PROVEN that no damage to the fen will occur.
Planning permission was granted erroneously due to the failure to present critical information to the committee, key evidence regarding the effects of the hydrology of the fen as not been given.
Other issues, in particular green space in themselves render this development highly undesirable.
This article is a synthesis of many inputs and much work from numerous persons, in particular from the FOLV, I do not claim it as my own work, any errors or omissions are entirely the author’s who has never lifted a finger to assist in Lye, nor is member of the FOLV.
Opinions expressed here are the author’s, the main purpose is to consolidate all known evidence and present it in a way that is understandable for busy people.
Many of the points made here are discussed in more detail here:
Codes are used above eg: REF: (WSP LQA)
Land Quality Assessment, Land East Of Warren Crescent July 2018, WSP Code: WSP LQA
Baseline Hydrogeological Report Feb 2019, WSP, Code: WSP Base
Investigation of the possible hydrological effects on the Lye Valley Sites of Special Scientific Interest and the riparian zones of the Lye and Boundary Brooks as a result of development on Southfield Golf Course, A Pre-EIA Assessment, Oct 2007,Dr Curt Lamberth Code: Pre-EIA
Technical Note Ecology, SUDS and Groundwater Quality 2015 Final , Peter Brett Code:PBA Final
Headington Heritage, A personal blog
Follow me on Twitter: @headingheritage
Version: 1.0 27/08/2019