HERTFORDSHIRE COUNTY COUNCIL DEVELOPMENT CONTROL …

Thorley Hall Farm Agricultural Reservoir

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HERTFORDSHIRE COUNTY COUNCIL DEVELOPMENT CONTROL COMMITTEE WEDNESDAY 26 MARCH 2014 AT 10.00 AM DISTRICT: EAST HERTS DISTRICT (1) PLANNING APPLICATION (3/1304-13) FOR PROPOSED EXTRACTION AND REMOVAL OF MATERIALS (SAND, GRAVEL AND SOIL) TO ENABLE CONSTRUCTION OF A 44 MILLION GALLON (200 000 CUBIC METRES) AGRICULTURAL RESERVOIR FOR FARM IRRIGATION PURPOSES TO INCLUDE THE TEMPORARY CONSTRUCTION OF A 3 METRE HIGH BUND AND A TEMPORARY INTERNAL HAUL ROAD, ANCILLARY BUILDINGS AND WEIGHBRIDGE AT THORLEY HALL FARM, THORLEY WASH, THORLEY, BISHOP’S STORTFORD, HERTFORDSHIRE AND (2) PLANNING APPLICATION (3/0117-14) FOR ENGINEERING WORKS TO CONSTRUCT AN UNDERGROUND PIPE FROM BROOKSIDE BUSINESS PARK TO SUPPLY WATER TO THE PROPOSED AGRICULTURAL RESERVOIR (3/1304-13) TO INCLUDE A HEADWALL, PUMP CHAMBER, ANCILLARY VALVE COMPARTMENT AND GRP KIOSK ON LAND BETWEEN THORLEY HALL FARM AND BROOKSIDE BUSINESS PARK, LONDON ROAD, SPELLBROOK, HERTFORDSHIRE Report of the Chief Executive and Director of Environment Contact: Felicity J Hart Tel: 01992 556256 Local Member: Councillor G. McAndrew

1 Purpose of Report

To consider two planning applications and an accompanying Environmental Statement for 3/1304-13

3/1304-13 (CM0951) for the construction of a 44 million gallon (200,000 cubic metres) agricultural reservoir for farm irrigation puposes together with ancillary development during the construction period (haul road, office, weighbridge and bunds).

3/0117 -14 (CM0951) for the construction of an underground pipeline from Brookside Stream to supply water to the reservoir.

These planning apllications are interlinked and are being considered together.

Agenda No.

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2 Summary

2.2 These planning applications are for the following connected

development : 3/ 1304 -13 is for the erection of a new 44 million gallon agricultural reservoir to include the removal of 200,000 cubic metres of sand and gravel during the construction process, together with the temporary construction of 3 metre high bunds and ancillary development. Planning application 3/0117-13 is for the construction and laying of a pipeline to carry water to the reservoir from Brookside Stream a tributary of the River Stort.

2.3 The reservoir application is an application to remove surplus material

(principally minerals and soils) arising from the construction of an agricultural reservoir. The application also includes the construction of a temporary haul road, ancillary office and weighbridge. It is envisaged that the removal of the minerals would take 3 – 4 years. When completed, the area around the reservoir would be landscaped.

2.4 The reservoir would be filled with water from Brookside Stream during

the winter months via a pipeline situated to the east of the reservoir site. The water in the reservoir would be used for farm irrigation in the summer months. The proposed pipeline comprises a separate planning application to be determined in conjunction with the reservoir application.

2.4 The pipeline application requires infrastructure which comprises a

headwall, pump chamber, ancillary valve compartment, Glass reinforced Plastic kiosk for the electronic control panel and connecting underground pipeline. Under high flow conditions, water from Brookside Stream would overflow via an inlet weir passing through the headwall and into a below ground pump chamber. From there it would be pumped by electric submersible pumps connected to the underground pipeline which would connect to the reservoir.

3 Conclusion

3.1 Planning Application no.3/1304-13 (Reservoir) It is recommended that permission be granted subject to approval by the Secretary of State and subject to the following conditions:

1. time limit for implementation of 3 years; 2. inform MPA within 2 weeks of commencement of development; 3. time limit for completion of 5 years from commencement; 4. approved plans; 5. Diversion Order of Bridleway 10; 6. the development to proceed and take place in accordance with

the Abstraction Licence;


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7. dust management scheme; 8. no processing of material on site; 9. effective sound insulation for all plant and machinery used on

site; 10. landscaping including details of fencing; 11. tree protection scheme; 12. no removal of trees or hedges in bird breeding season; 13. ecological and landscape management plan;; 14. bird hazard management plan; 15. written scheme of archaeological investigation; 16. details of the pumphouse; 17. hours of operation; 18. Construction Traffic Management Plan; 19. limit on HGV movements to be 100 (50 in, 50 out); 20. signage on site requiring left turn only for HGVs; 21. wheel washing and cleaning facilities; 22. removal of all bunds and ancillary temporary development and

plant at completion of the reservoir. 3.2 Planning Application no.3/0117-14 (Pipeline) It is recommended that

planning permission be granted subject to the following conditions:

1. time limit for implementation 5 years; 2. monitoring scheme on SSSI (Thorley Flood Pound); 3. Construction Traffic Management Plan; 4. Construction details of the laying of the pipeline.


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4 Description of the site and proposed development

The Reservoir

4.1 The site for the proposed reservoir is located in a rural area and comprises arable fields to the south of Bishops Stortford. A small ditch flows through the middle of the site with intermittant hedgerow of hawthorn and willow. Thorley Wood, part Ancient Woodland, important for its mature trees and interesting ground flora and lies to the north of the proposed site of the reservoir and the settlement of Thorley Wash (a linear settlement) lies to the east of the site along London Road. The site is situated in the Metropolitan Green Belt and is Agricultural Land classified Grade 2.

4.2 The application site would be accessed from St James Way (A1184 Bishops’s Stortford By-pass) and proposes the construction of a new haul road together with wheel washing facilities and a temporary portacabin to be used as an office. A temporary screening bund formed from soil, 2 metres high alongside the haul road is proposed, together with further temporary soil bunds (3 metres high) around the site of the proposed reservoir itself. The temporary grassed soil bunds are proposed to be constructed around the reservoir site which will retain topsoil and useful subsoil on site. They are intended both as a storage mechanism, and can also be used as a temporary screen for the working operation.

4.3 The construction of the reservoir would entail the removal of sand, gravel and soil and it is envisaged that this would take between 3 and 4 years to complete. The reservoir would be lined using on site clays and the site would be landscaped after construction.

4.4 During the construction period of the reservoir, the application states

that there would be likely to be a daily average of 80 HGV movements (40 in, 40 out) subject to a maximum of 100 movements (50 in, 50 out). The hours of operation are proposed to be 07.00 to18.00 Monday to Friday with no operations taking place on Saturday, Sundays or Bank Holidays.

4.5 The planning application for the proposed reservoir has been submitted as a method of water storage to irrigate local agriculture in the summer months. The proposed reservoir would have a storage capacity of 200,000 cubic metres of water. It is anticipated that up to 156,600 cubic metres would be needed for irrigation and surplus capacity is planned to allow for ‘bufferage’ of 30% to ensure that aquatic life and plants etc do not perish. The water used to fill the reservoir would be piped to the site from Brookside Stream (see The Pipeline).

4.6 A Public Bridleway crosses the site east-west and the route would need to be diverted slightly to the north along an existing farm track,as


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a result of the construction of the reservoir.

The Pipeline

4.7 The pipeline planning application site comprises a linear route through from the eastern side of Brookside Business Park where the kiosk and chamber would be located, along the entrance drive to the business park, under London Road and across the fields to the site of the reservoir. The purpose of the proposed pipe is to carry the water from Brookside Stream to the reservoir during the winter months when water levels are higher. An Abstraction Licence has been granted by the Environment Agency.

4.8 The land immediately to the north of the pipeline application comprises

Thorley Flood Pound which is an SSSI and comprises the area of land between London Road and The River Stort. Both site areas are situated in the Metropolitan Green Belt.

4.9 The infrastructure that is required to transfer water from Brookside stream to the reservoir comprises a headwall, pump chamber, ancillary valve compartment, Glass Reinforced Plastic (GRP) kiosk and connecting underground pipeline. This proposed equipment would be located in the yard at the rear of Brookside Business Park. Brookside Stream is located immediately to the east between the rear boundary of the site and the London – Cambridge railway line.

4.10 The pump chamber equipment has been designed so that when Brookside Stream is in high flow conditions, the water would overflow via an inlet weir passing through the headwall and into a below ground pump chamber. From there it would be pumped by electric submersible pumps connnected to the underground pipeline to the reservoir.

5 Consultations

5.1 East Herts District Council has no objections.

5.2 Thorley Parish Council raises concerns in relation to residential amenity as follows:

Working Hours -The working hours 07.00 am to dusk are totally unacceptable. The Parish Council recommends that no working or transport movements take place before 9.00 am and cease at 6.00 pm.

Dust Pollution -The movement of heavy plant and lorries will create constant dust on site, which will have a detrimental effect on houses in the vicinity of the site. All lorries must be sheeted, there should be suitable on site wheel washing


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facilities, regular cleaning of highways and damping of the site area to minimise spreading of dust.

Noise Pollution -During the 4 year construction period, local residents will have to bear constant noise from heavy plant and lorries. This will result in them losing their right to a quality of life, which all people are entitled to. They will be unable to enjoy the benefits of an outdoor life on their land, will be unable to put washing out and will have to constantly clean their houses (both inside & out). With the open nature of the site their must be measures put in place, eg all plant to be regularly serviced and fitted with silencers etc, to mitigate the affects of noise. In terms of the location and size of the reservoir the Parish Council has the following concerns:

has there been sufficient examination of alternate sites on farmland owned by him, which are not in the vicinity of houses and have less impact on members of the public? The Parish Council contends that this site has been chosen on financial grounds without considering impact on residents and public rights of way, which could create Health & Safety problems.

The Parish Council is concerned about the size of the reservoir (44 million gallon). Once again the Parish Council is concerned that there has been little consideration regarding a smaller reservoir.

In terms of flooding –

The proposed site is on an incline and not on flat land as recommended by Environment Agency.The bottom of this incline is at Thorley Wash, an area that has suffered over many years from flooding following heavy rainfall.

Any permission for the development of this site must include satisfactory arrangements to ensure protection of properties in Thorley Wash as well as highways surrounding the site.

The current storm drain will be inadequate to cope with any increased water flooding following heavy rainfall. Any permission for the development of this site must include satisfactory arrangements to ensure protection of properties in Thorley Wash as well as highways surrounding the site. The current storm drain will be inadequate to cope with any increased water flow.

In terms of Traffic –

All vehicles accessing and leaving the site should adhere to the prescribed routes, be subject to vehicle washing and must not exceed the daily allowance. There should also be noise monitoring on site.

The application could set a precedent.


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5.3 Environment Agency As these applications are intrinsically linked, we have considered them

together and provided one joint response. There are no objections to the planning applications, nor are we recommending conditions, although we would like to highlight one aspect of the development for further consideration.

The EA has concern that the land around the A1184 London Road and to the east of it may be affected by contamination. It is possible that the proposed pipeline cutting through this land could disturb that contamination and potentially cause pollution to groundwater and surface water. Mitigation measures have been proposed by the applicant to address this, however we do not agree with all of the measures.

Continuous site supervision is proposed together with the removal of contaminated materials to an appropriately controlled waste facility which is good however, we are not happy however with the proposed mitigation measure of immediately sealing the exposed faces of the excavation where contamination is identified with a membrane. This will significantly impede future attempts to clean up any contamination beneath or beside the pipeline. If any contamination is identified during development then this should be addressed following Environment Agency guidance and relevant good practice. The development should be carried out in accordance with the submitted flood risk assessment Thorley Reservoir Flood Risk Assessment, June 2013, ref: 61297R1 and flood risk mitigation measures detailed in the letter Thorley Hall Farm - Flood Risk Assessment for works at Brookside Business Park, London Road, 19 December 2013, ref: 61297R2.

5.4 Natural England has no objections and requests no conditions on the applications. The pipeline application is in close proximity to the Thorley Flood Pound Site of Special Scientific Interest (SSSI). Natural England is satisfied that the proposed development being carried out in strict accordance with the details of the application, as submitted, will not damage or destroy the interest features for which the site has been notified. We therefore advise your authority that this SSSI does not represent a constraint in determining this application.

In view of the location of this proposal, adjacent to a bridleway and in close proximity to both the Stort Valley and the proposed housing development area of Bishop’s Stortford, there may be scope for integrating the resultant reservoir into the local green infrastructure network through the enhancement of any links to other nearby habitat and/or landscape features.


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5.5 Canal & River Trust has no objections to either application. 5.6 Herts & Middlesex Wildlife Trust has no objections to either application

and respond that if permission is granted, then conditions should be imposed to ensure that the ecologist’s recommendations are adhered to during construction, and precautions are taken to avoid harm to protected species and the adjacent Local Wildlife Site. The following conditions are suggested:

The development and associated abstraction to proceed in accordance with the terms of the Abstraction Licence TH/038/0006/006 granted by the Environment Agency

Protection of Thorley Wood Local Wildlife Site

No removal of trees or hedges between 1st March and 31st August to protect birds.

Precautionary bat tree inspections of any trees to be removed to be undertaken prior to any work. If any bats, or signs of bats are found, no work to start until suitable mitigation has been drawn up and if necessary a Licence from Natural England has been obtained.

A final check for badgers to be done before commencement of development and if badger setts discovered then no site works to commence until a badger mitigation scheme has been submitted and approved by the LPA and implemented in full.

A Habitat Management Plan shall be submitted to the LPA for approval in writing.

Biodiversity enhancement scheme to be submitted for approval.

Reptiles awareness and if found then mitigation measures shall be followed.

Bat boxes to be erected on trees. 5.7 Thames Water

Inrelation to the pipeline application. Waste Comments: There are public sewers crossing or close to your development. In order to protect public sewers and to ensure that Thames Water can gain access to those sewers for future repair and maintenance, approval should be sought from Thames Water where the erection of a building or an extension to a building or underpinning work would be over the line of, or would come within 3 metres of, a public sewer.


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Thames Water will usually refuse such approval in respect of the construction of new buildings, but approval may be granted in some cases for extensions to existing buildings. The applicant is advised to contact Thames Water Developer Services.

Supplementary Comments: Your proposed works could affect our apparatus, the site crosses a pressurised rising main and a gravity sewer. Extra care should be taken at all times when excavating to avoid damaging our sewers and manhole covers. Depth of excavation above sewers must not exceed 0.6 metres unless the actual depth of apparatus has been checked in advance (by trial holes). In any event there should be at least 300mm clear between top of our apparatus and underside of any excavation. Where below 300 mm clear margin between top of our apparatus and underside of any excavation then machine excavation should cease. Any excavation below that to be hand-dug to expose the pipe at its crown but no further than waist - level.

5.8 Hertfordshire County Council – Highways

Reservoir application: No objections subject to conditions requiring no more than 100 HGV (50 in, 50 out) at the site on any one working day; the submission of a Construction Traffic management Plan; details of wheel washing facilities; and all HGVs shall turn left onto the A1184 in a north westerly direction.

Pipeline application: no objections subject to conditions requiring the submission of a Construction Traffic Management Plan and construction details of the laying of the pipe.

5.9 Hertfordshire County Council – Rights of Way - no objections. There is an existing bridleway (Thorley 10) which runs close to the site

of the proposed reservoir. This route will need to be diverted (would require a Diversion Order) and could be diverted to the exiting track through the field. At one point there would need to be a crossing of the bridleway by the haul road. This would be acceptable, provided that the bridleway is given a sealed surface at that point and is cleaned of mud regularly during operational activity. Warning notices would need to be provided on both sides of the haul road and the bridleway with reference to sudden noise. Vehicle speed should be limited and speed humps provided on the haul road on either side of the bridleway. Good sightlines should be provided and during periods of regular use, the provision of marshals should be considered.

5.10 Hertfordshire County Council – Archaeology

A desk based assessment has been submitted which shows a high potential for prehistoric archaeology and a moderate to high potential for


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Romano-British. The site is therefore likely to contain heritage assets with archaeological interest and a field evaluation should be undertaken. The NPPF (para 128) refers to where development sites may have the potential to include heritage assets with archaeological interest, local planning authorities should require developers to submit an appropriate desk-based assessment and where necessary, a field evaluation.

Further archaeological information will be required in relation to the reservoir proposal. This should be submitted to the LPA and will need to comprise the results of an archaeological field evaluation for the area land where the reservoir is proposed. If planning permission is granted, a condition should be attached requiring an Archaeological Written Scheme of Investigation to assess archaeological significance of the proposed development site and research questions together with provision to be made for a suitable programme of preservation in situ if appropriate.

5.11 Hertfordshire County Council – Ecology

The location of the proposed reservoir does not impact upon any ecological interest of particular significance as the current land-use is intensive arable cultivation. There is an existing ditch and hedge-line that runs through the site and this would be destroyed by the development of the reservoir. This feature is the remains of the former southern boundary of Thorley Wood which used to cover a much larger area than the current woodland up to the 1930’s. Its ecological and historic loss should be noted and a suitable new hedgerow and associated flora should be planted along the southern edge of the application site.

The remains of Thorley Wood (Wildlife Site) is adjacent to the proposed reservoir but unlikely to be directly affected as long as suitable measures are taken to avoid direct damage during construction. Grassland is proposed around the reservoir and this could provide numerous opportunities for ecological enhancement, although subsequent maintenance of grassland can only be achieved through grazing or cutting.

The proposals for landscaping, habitat creation and land management are insufficient. There is no objection on ecological grounds but it is clear that if ecological benefit is to be achieved further information will need to be submitted although this may be by condition. An overall ecological and landscape management plan is required to be submitted to the satisfaction of HCC.

There may be opportunities for the water body to have more ecological value and no wetland enhancements are currently proposed; these could be put forward in the management plan.


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No objection to the pipeline application, this will not affect the Wildlife Site.

The pumping and removal of water from the existing hydrological system is from a location immediately adjacent to a wetland SSSI, Thorley Flood pound. The application indicates that only surplus water from the Brookside Stream would be abstracted and that there would be no adverse impact on the local hydrology that could affect the SSSI. There could however be a monitoring of the wetland to ensure that it is not affected over three to five years to see if there will be any long term negative impacts. Therefore a suitable monitoring scheme should be required as a condition of approval

5.12 Landscape Landscape advice to the County Council concludes that the proposed

temporary soil bunds would be incongruous features and out of character with the existing landscape character. They would be removed when the reservoir is completed however. In the interim though the bunding would add to the short term loss of landscape character as well as having an adverse visual effect on views and loss of openness.

The creation of the reservoir, during the construction period, will result

in a substantial adverse effect on the actual site with the landform being significantly altered. However, once the land has been reinstated, it is considered that the proposals are capable of being absorbed within the character of the surrounding landscape.

Landscaping of the site following the construction of the reservoir is proposed and this includes fencing, planting and a pump house. Details should be required to be submitted for approval.

5.13 Agricultural Consultant’s Report The agricultural justification for an irrigation water storage reservoir on

the site is based on irrigating 178 ha of mixed arable crops each year within the overall area of 339ha. Water resources are limited in the Upper River Lee catchment and new abstractions are likely to be subject to flow constraints that limit the periods in which water can be taken and stored for subsequent use, however the applicant has already obtained an Abstraction Licence.

Climate change models suggest that irrigation of crops will become increasingly necessary up to and beyond 2050. the conclusion of the appraisal of the agricultural justification for the scheme is that the increased gross margin likely to be associated with the provision and full operation of the proposed irrigation system is minimal using today’s costs and crop valuations, making the provision of the facility neutral in economic terms.


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However, given the insecurity of water supply in the area and the likely medium –term impacts of climate change, the provision of an irrigation system at the site may be considered necessary to ensure a sustainable farming business in the long term.

5.14 A total of 98 consultation letters were sent out (in respect of both applications) and 3 letters objecting to the applications were received. One in relation to the reservoir and 2 in relation to the pipeline application. The issues of concern can be summarised as:

Lack of consultation

Significant risk of flooding

Detriment to local residents through noise and dirt pollution

Insufficient consideration to alternative locations

Viability of the application

Concern that the abstraction of water from the Brookside Stream may have an adverse impact on land and the SSSI and adjoining water table.

5.15 In addition comments have been received from East Herts District

Councillor Mike Carver regarding flooding, depth of the reservoir and the water table, the location of the reservoir, landscaping, effect on rights of way and if permission is granted that the site should not be used for any recreational activity.

5.16 Publicity for the application was as follows: In addition to the consultation letters, site notices were erected on 29th July 2013 and 19th February 2014 and the application was advertised in the Herts and Essex Observer on 18th July 2013 and in the Herts and Essex Observer on 30th January 2014

6 PLANNING POLICY

National Planning Policy Framework 2012 (NPPF)

6.1 The NPPF was released in March 2012. The NPPF contains the presumption in favour of sustainable development. The document also promotes the development plan as the starting point for decision making and that decsions should be made in accordance with an up to date Local Plan unless material considerations indicate otherwise.


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Development Plan 6.2 The Development Plan is the Hertfordshire Minerals Local Plan Review

2002-2016 (Adopted 2007) and the East Herts Local Plan Review 2007. Given the age of the plan and the introduction of the NPPF the policies in the plan need to be balanced and given due weight against the NPPF. The NPPF is a material consideration and how policies from the Development Plan are in conformity with it need to be considered. This will vary depending upon individual proposals and how they relate to the NPPF and the Development Plan and the overall intentions of the relevant document.

6.3 The relevant development plan policies are:

Hertfordshire Minerals Local Plan Review 2007 Minerals Policy 1 – Aggregates Supply

Minerals policy 2 – Need for Mineral working Minerals Policy 4 – Applications outside preferred areas. Minerals Policy 5 – Mineral sterilisation Minerals Policy 9 – Contribution to biodiversity Minerals policy 12 – Landscape Minerals policy 16 – Transport Minerals policy 18 – Operations criteria.

East Hertfordshire Local Plan Review 2007 Policy SD1 : Making development more sustainable Policy GBC1: Appropriate Development in the Green Belt

Policy GBC12 ; Agricultural land Policy GBC14 : Landscape character Policy TR3 Transport Assessments Policy ENV2 Landscaping Policy ENV17 Wildlife Habitats Policy ENV22 On-Farm Reservoirs Policy LRC9 Public Rights of Way

7 Planning Issues

7.1 The principal issues to be taken into account in determining this application are:


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The principle of the proposed mineral extraction, the need for the extraction and the submitted justification in the application;

Impact on residential amenity and flooding;

Impact on highway safety;

Impact on Rights of Way:

Impact on landscape, both temporary and long term;

Impact on biodiversity:

Impact on archaeology;

Green Belt

Need and justification

7.2 The planning applications have been submitted to enable the construction of a large agricultural reservoir situated in a rural area to the south of Bishops Stortford.

7.3 In order to create a void large enough to take the required quantity of

water (44 million gallons), a large quantity of mineral (sand and gravel), would need to be dug (200,000 cubic meters). This sand and gravel would be a small but significant resource in terms of Hertfordshire’s overall landbank.

7.4 The ‘landbank’ is the stock of planning permissions for the winning and

working of minerals. The Minerals Local Plan policies seek to ensure that an adequate landbank is provided from Hertfordshire and has identified preferred sites for this. The policies therefore have a presumption against approval of new permissions on new sites.

7.5 The only exceptions to this presumption in favour of preferred site are

proposals which would not prejudice the timely working of preferred areas and resources at risk of sterilisation in Policy 4. Policy 5 encourages mineral extraction prior to other development taking place.

7.6 The Hertfordshire landbank currently stands at 11.4 years (AMR 2012).

The actual amount of reserves currently available are less as the permission for Rickneys in Hertford has just expired though a resolution has been taken to grant planning permission and a year of sales has occurred since the landbank figure was calculated. The NPPF requires that MPAs should look to provide maintenance of landbanks of at least 7 years for sand and gravel. Currently Hertfordshire’s published landbank exceeds the level of landbank suggested (at about 11.2 years) and also taking the current position into account with the loss of Rickneys planning permission and depletion through sales.

7.7 Under the NPPF, the status of ‘need’ has however been lessened,

which states that “great weight” should be given to the benefits of mineral extraction although in granting planning permission there should be no adverse impacts on the natural and historic environment, human


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health or aviation safety and take into account the cumulative effect of multiple impacts from individual sites or from a number of sites.

7.8 There are several active minerals sites in Hertfordshire currently and the

NPPF says that MPAs should ensure that the supply of aggregates in policy terms should not be bound up in very few large sites. The County is commencing a review of its mineral plan and this issue will be reviewed. The application site is small, in minerals terms, and would be consistent with the thrust of national policy in the NPPF seeking to ensure that the supply is widened to come from more than just a few very large sites. The site is not at risk of sterilisation and would remain within a farm.

7.9 It is therefore considered that although the reservoir site is not classed

as a preferred site, as identified in the Minerals Local Plan, the NPPF now places great weight on the benefits of mineral extraction and although the primary purpose of the reservoir application is to create a water body for farm irrigation, the net result will be a mineral extraction. In granting planning permission, the NPPF also seeks to ensure that there would be no unacceptable adverse impacts on the natural or historic environment, human health or aviation safety as well as cumulative effects from a number of sites in the locality. It is considered that there would be no cumulative effects and in terms of mineral policy the proposal is considered acceptable. The other considerations are assessed elsewhere in the report.

Agricultural justification

7.10 The main justification for the proposed development in the planning applications is that a considerable amount of water will be required in forthcoming years to irrigate the farmland and allow appropriate crops to be grown. Climate change models suggest that by the 2050s, summers in the south east of England will become drier and winters wetter and this will change river and groundwater regimes. Combined with water storage on farms and future choice of crop, this change to the water balance in the future is likely to provide a better economical return for irrigation of a wider range of crops, possibly including cereal crops in places where irrigation infrastructure becomes available.

7.11 Thorley Hall Farm lies in an area which relies on the underlying

groundwater for much of its flow of water currently, with a small proportion derived from direct runoff. There is an increasing demand for water in the area for a variety of uses and given this pressure for water strategies needs to be adapted to provide resilience and allow the improvement in terms of the efficiency of resource use.

7.12 The application proposes winter abstraction and summer storage and is

considered to be an accepted way of building in resilience to areas of


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low flows, thereby providing some degree of resilience to climate change.

7.13 The farm currently has no irrigation available and the proposal has been

calculated to show that it would provide a resource which would be adequate in 15 years out of 20. It is likely that the annual demand based on the likely cropping pattern would have standard crop water requirements in the region of 156,500 cubic metres. The reservoir has been designed to provide a net 163000 cubic metres of water in any year, allowing for 20% loss to evaporation and seepage and that would result in a reservoir capacity of 203,000 cubic metres. This calculation means that in most years there would be about 6,500 cubic metres on average remaining in the reservoir at the end of the irrigation season. Any greenfield run-off and rain absorption would also be contained within the reservoir.

7.14 It is possible however, that in some years it may not be possible to

abstract the water required to replenish stocks due to restrictions with the Abstraction Licence in times of low rainfall and therefore in such situations the ability for the farm to irrigate the following year may be compromised, however this scenario is not compatible with the predicted likely scenario of wetter winters so is impossible to predict accurately.

7.15 Economically there would be an improvement to the farm business if

irrigation is allowed to take place, although 9ha of best and most versatile land would be lost for the development and there would be other costs. A cost-benefit analysis has been undertaken by an independent consultant for Hertfordshire County Council which advises that with the full operation of the proposed irrigation system, overall profit would be minimal, making the provision of the facility neutral in economic terms. However, given the insecurity of water supply in the area and the medium-term predicted impacts of climate change, the provision of an irrigation system may be considered necessary to ensure a sustainable farming business on the land in the long term.

Landscape

7.16 The site for the agricultural reservoir comprises open fields, situated in the Green Belt, currently in arable use together with a ditch containing sporadic vegetation. To the north of the site lies Thorley Wood, an area of Ancient Woodland together with some additional more recent deciduous woodland. It is a designated wildlife site.

7.17 The area has an open, rural character, being situated to the south of the

Bishops Stortford. The River Stort lies to the east in the valley with the land rising gently towards the site of the proposed reservoir. The proposed pipe application site runs from the eastern edge of the yard of the Brookside Business Park along the access road, under London Road and then directly across the fields to the reservoir. With the


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exception of the proposed kiosk and chamber, the whole of that development would be below ground and will not affect landscape.

7.18 Mineral Local Plan Policy 12 requires that development proposals are

expected to respect landscape character both during operations and in proposals for reclamation; ensure that any distinctive landscape features are protected from the impact of the development and be accompanied by landscape conservation, design and management measures that both strengthen the character and enhance the condition of the landscape.

7.19 The access to the site is proposed from the A1184, which is the existing

access to Thorley Hall Farm and is edged with a mature hedge with more recent tree planting. A new haul road would be created on the southern side of the hedge running parallel to the A1184, however it would be well screened.

7.20 The construction of the proposed reservoir would take place over a 3 – 4

year period while the mineral is extracted to create the void for the water. During the construction period there would be a temporary effect on landscape character with large scale equipment involved in the working. It is proposed to build temporary soil bunds however, which will retain topsoil and subsoil on site and these will be partially visible. They will however become quickly covered in vegetation and they will screen the heavy working equipment from view.

7.21 There are limited views into the site due to its location, although there is

a public footpath/bridleway that runs through the field adjacent to the development site and this will provide the closest views. Some properties including Thorley Hall (being the closest) will have some views but during the construction period there would be bunds built which would screen from any visual impact.

7.22 Although the visual impact of the reservoir development during

construction, would be moderate to high from selected locations, this would just be during the extraction period. It is considered that once completed and landscaped the proposal would be in accordance with Minerals Policy 12 which would strengthen the character and condition of the landscape.

Highways

7.23 With regard to the pipeline application, the site is located to the rear of Brookside Business Park situated behind properties fronting the A1184 London Road, Spellbrook. Brookside stream runs along the eastern boundary of the business park separating it from the main London to Cambridge railway line.


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7.24 The headwall, pump chamber, ancillary vale compartment and GRP control kiosk that are proposed would be located within an existing concrete area historically used for open storage of materials close to the railway line and currently used as an overflow car park to the Brookside Business Park. The pipeline is proposed to be installed beneath the access road to the commercial premises, under London Road and continue underground beneath farmland to the reservoir.

7.25 The underground pipeline route will run due west through ground which rises from its lowest point at 52 metres AOD to 60 metres AOD on the eastern edge of the reservoir. It is considered that the installation of the pipeline under the A1184 London Road would not be likely to affect the normal operation of traffic on the A1184 as it is intended to thrust bore the pipeline under the carriageway. However this work will require the applicant to seek permission from the Highway Authority to carry out work under the highway which in turn will require them to enter into a legal agreement. There are no objections to this application form a highway point of view.

7.26 With regard to the reservoir application, the applicant has agreed to a restriction on the routing of HGVs leaving the site in order to minimise disruption to other road users. Conditions are proposed as follows; all HGVs would be required to turn left only when exiting the site; there shall be no more than 100 HGV movements at the site in any one working day; a Construction Traffic Management Plan shall be submitted and wheel washing facilities provided. Subject to these conditions the Highway Authority has no objection to the proposal.

Biodiversity

7.27 The location of the proposed reservoir does not impact upon any ecological interest of particular significance, however the proposals will destroy the existing ditch and ‘hedge-line’ which lies across the middle of the site. The ditch comprises the remains of an ancient boundary and this would be an ecological and historic loss. A new suitable hedgerow and associated flora can be planted as a replacement around the southern edge of the application site which would become a new habitat and landscape feature. There are no objections to the proposals on ecological grounds.

7.28 However, suitable measures should be taken to avoid direct damage of

Thorley Wood Wildlife Site during construction and the area around the proposed reservoir which is proposed to be grassed should be managed by grazing if at all possible. An amended landscaping plan has been submitted.

7.29 An overall ecological and landscape management plan will be required to

be submitted to describe suitable landscaping, habitat creation and land management of the reservoir site once completed. This should outline


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appropriate trees, shrub and grassland mixes and subsequent management requirements. No wetland enhancements are proposed at the site of the reservoir and there may be opportunities for a more ecologically valuable water body to be created. Further details on this can be submitted as a requirement of a landscaping condition.

7.30 It is considered that the pipeline application would not affect the Wildlife

Site and although water from the existing hydrological system would be removed from a location adjacent to a wetland SSSI (Thorley Flood Pound) it is likely that the SSSI would not be affected. Monitoring, including a survey of wetland indicators followed by an updated survey in three or five years to establish if there has been any negative effect on the SSSI would assist the Environment Agency in the future.

7.31 Although normally a new body of water would be designed to encourage

use by waterfowl, in this case the reservoir site is immediately under the flightpath from Stansted Airport. Being in the Safeguarding Zone the bank design of the reservoir embankment is proposed to be a 1 in 3 slope with no shallow edges to deter waterfowl such as geese and swans. Fencing and planting around the edges will also deter larger species.

7.32 Bird Hazard Management Plan will be submitted which will be designed

to deter a range of species through the design and operation of the reservoir. However, it is considered that this should be designed with regard to maximising other biodiversity at the site.

7.33 It is therefore considered that both proposals comply with Minerals

Policy 9 with regard to contribution to biodiversity. Archaeology

7.34 Evidence shows that the site has a high potential for prehistoric archaeology and a moderate to high potential for Romano-British. The site is therefore likely to contain heritage assets with archaeological interest and a field evaluation should be undertaken.

7.35 Further archaeological information will be required to be submitted in

relation to the reservoir proposal. This will need to comprise the results of an archaeological field evaluation for the area of land where the reservoir is proposed. An Archaeological Written Scheme of Investigation to assess archaeological significance of the proposed development site and research questions will need to be undertaken before development commences and provision made for a suitable programme of preservation in situ if anything of significance is located..


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Green Belt 7.36 In the NPPF (para 90), certain forms of development such as mineral

extraction are referred to as not inappropriate in the Green Belt provided they preserve the openness of the Green Belt and do not conflict with the purposes of including land in the Green Belt.

7.37 Although the proposed development is ostensibly to create an

agricultural reservoir for irrigation at Thorley Hall Farm, the operational development would in itself result in the extraction of minerals which would be used elsewhere. It is for this reason that the application is determined by the County Council as a minerals application.

7.38 It is envisaged that it would take 3 – 4 years to remove all of the material

to create the reservoir and during that time, the bunds created to store top soil would adversely affect openness in the vicinity. However, this would be for a temporary period of time and once completed and landscaped, the reservoir would not affect openness and would merge into the rural landscape.

7.39 Although it is acknowledged that harm would occur in the short term, the

long term result of the proposed development would have no impact on openness and therefore there is no conflict with Green Belt policy provided the timescales to achieve the completed reservoir at the earliest opportunity are adhered to.

Rights of Way

7.40 Bridleway 10 which cuts across the site would need to be diverted as a result of the reservoir development. A Diversion Order would need to be made before development commences. The new route would follow an existing farm track to the north of the reservoir which is a route which is used currently and is an acceptable route. It would cross the proposed haul route whilst construction takes place, however, this will be acceptable with the necessary adjustments. There will be no adverse effects on users of the Bridleway.

Residential Amenity and Flood Risk

7.41 There are few residential properties in close proximity to the reservoir site. The nearest dwellings are at Thorley Wash on the west side of London Road (230 metres from the reservoir site). The topography means that these houses are at a lower level than the site of the reservoir. Three metre high bunds are proposed to be constructed around the site of the proposed reservoir and these would act as noise attenuation barriers, with on site digging taking place behind the bunds. Soils will have to be handled when dry and friable and once stripped the


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risk of soil blow would greatly reduce as the mineral would have a high residual background moisture content.

7.42 Dampening of the site with bowsers is proposed in the event of very dry

conditions and it is considered that together with the use of a dust management scheme, there would be no adverse effect on local residential amenity.

7.43 A land drain (surface) flows from the site of the proposed reservoir

eastwards in the direction of London road and close to residential properties at Thorley Wash. This follows the ditch in the middle of the site that would be removed. Concern has been expressed that the proposed reservoir development would cause more significant flooding to occur at Thorley Wash. The construction of the reservoir would cut into the route of the ditch and it is therefore proposed to divert the ditch to the south west of the reservoir site and re-construct with weirs and small ponds. A scheme for the details of this would be required to be submitted.

7.44 It is intended to carefully manage the water level in the reservoir and

water will only be abstracted from Brookside Stream when levels in the stream rise. In the rare event that the reservoir becomes too full, an overflow pipe is proposed that would run parallel to the fill pipe and would return water to Brookside Stream. This is likely to be an extremely rare occurrence.

7.44 The Environment Agency raises no objections to the development and

requires that the development be carried out in accordance with the submitted Flood Risk Assessment. It is considered that the proposed development will not increase flooding in the local area.

8 Conclusions

8.1 Planning permission has been sought for the construction of an agricultural reservoir (3/1304-13) to allow the future irrigation of crops on Thorley Hall Farm. The potential impact of climate change in the future is likely to result in increased demand for pressure on water and combined with the agricultural justification provided is considered to be acceptable in principle.

8.2 In order to construct the reservoir a mineral extraction operation over a 3-4 year period would need to take place and this has been assessed

against potential harm that would take place to the Green Belt, biodiversity, landscape, archaeology, highways, flood risk and residential amenity. It is concluded that the potential harm that could accrue would be over a relatively short term period and could be


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mitigated sufficiently through schemes and conditions. It is therefore recommended that planning permission be granted.

8.3 In order to supply the reservoir with water, planning permission has

been sought for the construction of a pipeline (3/0117-14) and ancillary equipment to abstract water from Brookside Stream to be piped up to the reservoir. An Abstraction Licence has already been granted by the Environment Agency and the equipment has been designed to only take water from Brookside Stream at times of high flow. The intention being that the reservoir will be filled annually during wet winters and the water stored on site to irrigate the farm during dry summers. The principle behind the proposal has been designed with regard to climate change and as only excess water would be taken from the stream, the proposal is considered to be a sustainable one consistent with policy and the NPPF.

8.4 It is therefore recommended that planning permission be granted for

both the agricultural reservoir application and the pipeline application subject to conditions. The operational work to construct the reservoir is anticipated to take up to four years and the development of the pipeline would not need to be undertaken during this time. Therefore a longer time period for commencement of development is recommended (5 years).

Background information used in compiling this report Planning application no.3/ 1304 -13 and accompanying Environmental Statement

Planning application no.3/0117-14 Consultees responses and representations Relevant policy documents Hertfordshire County Council Minerals Local Plan Review adopted 2007 East Herts Adopted Local Plan Review 2007 Agricultural Report by Reading Agricultural Consultants Ltd

Documents

HERTFORDSHIRE COUNTY COUNCIL DEVELOPMENT CONTROL …