England and Wales High Court (Queen's Bench Division) Decisions

IN THE HIGH COURT OF JUSTICE
QUEEN'S BENCH DIVISION
LEEDS REGISTRY

		Leeds Combined Court Centre, 1 Oxford Row, Leeds, LS1 3BG
		29/01/2016

Mr Justice Dove :

Facts

1. On 24^th October 2013, the interested party applied to the defendant for planning permission for the construction of 12 dwellings on one hectare of land at Bingley Road, Menston. Local residents recalled that the application site had been designed to operate as a detention basin following the filling in of a lake on adjacent land at Red House Gardens for the construction of housing. They therefore objected to the proposed development on the grounds of flooding, on the basis that the application site was regularly inundated with water which often spread onto the land of existing adjacent properties. Other grounds of objection were also raised to the proposed development in representations to the defendant who are the local planning authority.
2. As part of the evidence supporting the interested party's application, they provided a report entitled "Flooding and Draining Assessment" ("FDA") dated 28^th March 2014. The FDA noted that there was a watercourse running across the site in a pipe or culvert. The report also noted that on the Environment Agency flood map the site was within zone 1, which meant that according to that information it had a less that 1 in 1,000 year probability of flooding. The FDA acknowledged, however, that the evidence on the ground presented a different picture. In respect of fluvial flooding the report observed as follows:

"Fluvial

The site is within Flood Zone 1. This zone comprises land assessed as having less than a 1 in 1000 (<0.1%) annual probability of tidal or river flooding in any one year.

It should be noted the watercourse on and adjacent to the site may be a source of localised fluvial flooding that has not been captured on the EA flood zone map. As a section of the water course on the site is piped and the pipe capacity may cause a restriction to flow in times of heavy rainfall and result in localised flooding to the immediate upstream open section of the watercourse.

In time of extremely heavy rainfall, local residents have reported that flooding has been apparent on the site up to a depth of approximately 0.4m.

A catchment area analysis has been undertaken of the watercourse that crosses the site and the 1:100 year flood level has been modelled as 147.70. The flood modelling analysis undertaken is attached in Appendix F.

Three dimensional modelling has shown the flood volume on the site is 216.3m³. The extent of the modelled flooding on the site is indicated on Fig 3 attached in Appendix G.

Runoff

From the inspection of site levels and ground levels to the surrounding properties to the northeast of the site, it appears that the north eastern sector of the site is in a 'bowl'. Therefore any overland waters either from surface runoff or from overtopping of open section of the watercourse will run into this area and accumulate. It is also apparent that once water has accumulated in this area of the site it cannot drain into the piped watercourse under this area of the site.

It is evident from several site visits made by CoDA Structures water does pond on the surface over the line of the piped watercourse to a depth of approximately 75mm. The surface flooding observed by CoDA Structure appears to be an accumulation of surface water runoff from the field which cannot drain into the piped watercourse as the open watercourse itself has not been in flood."

3. The FDA also gave consideration to the wider catchment in the following terms:

"Effect of Development on the Wider Catchment:

The proposed development will result in impermeable area on the site and therefore unattenuated surface water flows from the development, if not addressed, would increase the flood risk to the site and local catchment."

4. The FDA moved on to consider proposals in relation to flood risk mitigation. The analysis which it presented, which it is necessary for the purposes of the arguments presented to quote at some length, was as follows:

"Flood Risk Mitigation:

As part of the development of the site it is proposed to divert the piped section of the watercourse. In order to maintain the hydraulic characteristics of the piped section of the watercourse and not increase flows, the watercourse diversion will be undertaken in 300mm diameter pipes. The watercourse diversion will require formal consent from BMDC – Drainage. The proposed diversion route of the watercourse is shown on he Schematic Level and Drainage Scheme (Fig.5) attached in Appendix L.

The flood storage volume before 147.70m AOD on the site will be increased to 324.0m³. The proposed flood compensation areas indicated on Fig. 4 are attached in Appendix H. The provision of flood storage has also been verbally discussed with BMDC Drainage Department (Mr E Norfolk) and it was advised it would be acceptable to provide the flood storage below ground by using, for example, a crate system…

The site surface water drainage system will be designed to restrict discharge to the piped water course on the site to greenfield run off with stormwater storage provided on the development for storms up to a 1:00 year event plus an allowance for climate change. BMDC Drainage Department (Mr A Davison) verbally advised that surface water discharge to the watercourse on the site should be restricted to greenfield runoff (1.6 lit/sec/ha) but for 'practical' reasons with regard to flow control units a discharge rate of 5.0l/s would be acceptable. It should be noted that the green field run off for the catchment was calculated as 8.2 lit/sec/ha in the Eastwood & Partners Report which equates to 8.2 l/sec for the site.

With reference to the Eastwood and Partners FRA Report, the following parameters were used for the volumetric discharge for the 1:100 year storm:-

1:100 year discharge rate 24.2 l/sec

Total rainfall for the 1:100 year event = 57.4mm

Using these values the volumetric discharge for the site using the traditional percentage calculation is 0.3 x 0.0574 x 10 000 = 172.2m³.

The proposed discharge rate from the developed area of the site is 5.0l/sec (see Section 4.0). Therefore the volume discharged in 6 hours would be 5.0 x 60 x 60 x 6 = 108,000 litres (108.0m³).

The volume discharged from the undeveloped area of the site would be 0.3 x 0.0574 x (10 000 – 4390) = 96.6m³.

The gives a total discharge of 204.6m³ an increase of 32.4m³.

However, the flood compensation proposed on the site would give an additional 106.7m³ of storage which is more than sufficient to store the additional discharge from the site as the flow off the site is always restricted by the 300mm diameter piped section of watercourse.

The proposed management of surface water runoff from the developed site together with the flood storage volume provided below the existing 1:100 flood level of 147.70m AOD will not increase the risk of flooding both on and down stream of the site.

If the discharge rate from the developed area exceeded 5.01/sec for any reason it should be noted that an additional flood storage volume of 106.7m³ has been provided on the site below the 1:100 flood level of 147.70m AOD."

5. The drainage solution which was proposed by the FDA within the context of the setting of the site as part of the wider catchment was described in the following terms:

"For storm a of a given duration and return period the volume of water falling onto a catchment will be the same in the pre and post development state. The difference is how this water is managed and in the run off response time. The response time in the developed state is much quicker as flows are drained towards a defined point in a drainage network whilst in the undeveloped state rainfall will shed at a lower rate and will be subject to natural losses such as evaporation and infiltration.

It should be noted any rainfall on the pre-developed site would shed by overflow routes either towards the water course and the rear gardens of the properties on Red House Gardens.

In the developed state rainfall on the development will be captured in the gravity drainage system for flows up to the 1 in 100 year plus climate change event. These flows would be discharged at a managed rate of 5.0l/sec to the piped watercourse. Stormwater storage will be provided on the development in the form of oversized pipes for a 1:100 year storm return period and a 30% increase in rainfall intensity for climate change.

The following estimation of stormwater storage requirements for the development has been based on the following parameters:

Hardcover area 2190m²

Discharge rate 5.01/sec

Stormwater storage 199.2m³

It should be noted that in the final design approximately 765m² of drive area will be drained into the soils adjacent the Poplar trees.

A gravity system can be adopted on the development.

The stormwater storage calculations for the proposed system are attached in Appendix L."

6. As noted in the text, the drainage calculations which were necessary to formulate the requirements for the drainage design were contained within Appendix L of the FDA. The summary of those calculations noted that onsite storage was designed to accommodate design flows generated by run off from areas of development for a 1 in 100 year storm (with an additional 30% volume to accommodate climate change) along with a pass forward flow which was limited to 5l/sec. As a result of the calculations using these parameters, the maximum storage volume that was identified as being required at the site for the purposes of the impermeable areas following development was 199.2m³. The summary schedule recorded the following in relation to the surface water strategy:

"Surface Water

Ground conditions on the site are such that the use of conventional soakaways on the development is not considered to be a viable solution for the disposal of surface water from the development.

It is proposed that a separate surface water drainage system be provided on the development discharging to the watercourse on the site.

Based on a proposed total drained hardcover area of 2190m² and a discharge rate of 5.0l/sec a storage volume of 199.2m³ should be provided on the site, based on a 1:100 year storm return period with a 30% increase on rainfall intensity to cater for climate change.

It should be noted that in the final design approximately 765m² of drive area will be drained into the soils adjacent the hybrid Poplar trees."

7. Various plans and illustrations accompanied the FDA. Amongst the plans was one that described the flood compensation areas which were proposed as part of the development. These areas provided above ground surface water storage facilities. The plan included a calculation which showed that the existing flood storage area on the site was 216.3m³, and that the proposed flood storage area in the form of two areas of the surface of the site designed to flood amounted to 323m³ (comprising two areas of 251.6m³ and 71.4m³), leading to a net gain in external surface water storage of 106.7m³. A further plan was also provided with the FDA entitled "Schematic for External Works" and identified as drawing 6984/Fig5 RevA. Amongst other details this plan showed, firstly, the details of the hydro-brake within the below ground system for attenuating the flow from surface water drainage of impermeable elements of the development to 5 l/sec. It also showed the proposed underground surface water conveyance and storage infrastructure, described as comprising "2.1 x 1.5m box culvert with dry weather flow channel to give 199.2m³ of storm water storage".
8. On 14^th August 2014 the application was reported to the defendant's committee charged with the responsibility of deciding whether permission should be granted. They were assisted by an officer's report ("the report"). In the report it was noted that the Environment Agency had no objection to the proposed development subject to the requirements of the FDA being imposed by a condition. Similarly Yorkshire Water did not object subject to appropriate conditions upon which they provided advice. The defendant has internal experts on drainage. Once more, subject to the imposition of conditions incorporating the approach taken by the FDA, no objection was raised by the defendant's drainage engineers.
9. In the officer's appraisal of the planning merits of the application the conclusions in respect of land drainage were as follows:

"Land Drainage

Following the extensive discussion on issues of land drainage, the Councils Drainage section has reviewed the objectors' submissions and the applicant's response, on this matter. The commentary below forms the appraisal of land drainage matters.

Consideration has been given to all the submitted reports from the applicant and objectors in relation to the drainage characteristics and proposals for the Bingley Road site in Menston. The evaluation has been made on the basis that the matter before Committee is a proposal to develop the site so as not to increase existing flood risk, not a scheme to remove it. It is therefore against the former legislation [WHAT LEGISLATION?] that the applications have been assessed.

Surface water discharge from the site.

As development will normally increase the runoff rate of the site, therefore the final surface water flow rate will have to be restricted if no increased run off is to occur. The principle used to set a low rate is to ensure it is not an increase from the existing sites runoff rate for the rainfall events of 1:1 year and 1:100 year. In the case of the two application sites, as they are currently undeveloped, the limiting discharge rate will be set no greater than the existing Greenfield runoff rate. The method for calculating the existing Greenfield runoff rate according the British Standard 8582:2013, Code of practice for surface water management for development sites, and for sites less than 50 ha the IH124 method should be used. This method has been used on both application sites.

The Chartford Homes site is approximately 1.0 hectare in size. The existing Greenfield runoff rates for the site have been correctly calculated using the IH124 method as 1:1 year = 8.2litres/second and 1:100 year = 24.2 litres/second. The proposed discharge rate will be set to 5litres/second and is therefore a considerable reduction for both the 1:1 year and 1:100 year existing flow rates.

The proposed discharge rate of surface water from both development sites therefore will not increase flooding but reduce it and is therefore acceptable.

Surface water storage serving the new development sites.

With a restriction imposed on the surface water runoff it is required that the development provides water storage facilities to hold excess water during heavy rainfall events. The exact amount of storage required is determined during the detailed design of a drainage system as the falls and sizes of pipelines has an affect on how quick water is distributed around a system. At planning stage the drainage department needs to be satisfied that the estimated storage amount can be achieved within the development's layout.

The Chartford Home site estimates a storage requirement in the region of 199m³. The drainage department has used their own storage calculations to verify this estimate. The submitted drainage strategy drawing 6984/fig5 Revision A prepared by CODA Structures, proves the estimated storage can be fitted within the site layout.

The risk of flooding is reduced by the designed storage tank and is therefore acceptable…

Groundwater flooding

…

Ponding has been experienced on the Chartford Home site during prolonged rainfall events. The emergence of flood waters has been assessed using a hydraulic flood model of the unnamed watercourse that passes through the site. Flood levels and volumes have subsequently been calculated for the existing site. Witness statements also provide photographic evidence of flood waters and levels on the site. The source of the flood water has been suggested to be from both ground water and surface water runoff. The Chartford Homes site therefore proposes to provide flood storage within the site boundary. The flood storage provided equates to 50% more than what the site currently provides to the catchment. The storage provided is adequate to cater for the flooding modelled by the hydraulic flood model and also the flooding witnessed by residents detailed within the objectors report. The finished floor levels of the development will be set 600mm above the calculated 1:100 year flood levels and are therefore above the existing ground levels and witnessed flood levels…

Surface Water Flooding

A development should not increase the quantity and velocity of surface water run-off through the site, in accordance with planning policy.

The submitted proposal complies with the relevant legislation for managing surface water of the application site. The documents submitted on behalf of objectors are not relevant in terms of development proposal, the rainfall events referred to fall outside the range that can be considered for a development proposal. Consideration of such events would be appropriate if this were a flood alleviation scheme, even then though the volumes based on a methodology derived from observed from photographs for a single event is not robust or would stand expert scrutiny.

Existing flows through the Chartford Home site has been modelling using industry recognised methods and the flood levels derived are close to the observed levels witnessed during the flooding events in September. The modelling undertaken also concurs with Environment Agencies surface water flood maps. As discussed above the Charford Homes site proposes to add an additional 50% of contribution storage volume to the site and therefore flood risk from overland surface flows will be reduced.

In conclusion therefore the measure proposed for the site are reasonable and meet the appropriate regulatory requirements."

10. In the light of this analysis, and the absence of any other reason to refuse consent, the officers recommended the grant of planning permission. During the course of public representations to the committee a parish counsellor observed that the proposal did not take opportunities to reduce existing flood risk and aired this as a reason that permission should be withheld. In response to this and other observations the defendant's solicitor read to members paragraphs 100 and 101 of the National Planning Policy Framework ("the Framework") set out below. Ultimately members resolved to grant planning permission subject to conditions and the completion of a section 106 planning obligation.
11. On 28^th August 2014 the claimant's solicitors wrote to the Environment Agency questioning their consultation response on the following basis:

"Some 20 years ago the Environment Agency specifically supervised the construction of the overflow system at the site to ensure that the site acted as a Detention Basin after allowing the adjacent lake on Red House Gardens to be filled in. It has acted as designed for many years with a large lake forming over the site and adjacent gardens…"

12. An illustrative photograph demonstrating the flooding of the site was attached. On 17^th October 2014 the Environment Agency replied to that correspondence in the following terms:

"We have looked into the matters raised by Mr Schofield [the claimant's solicitor] and can confirm that at the time our consultation response was provided, we had no information that suggested that the site was subject to any specific drainage problems. Furthermore we hold no record that the Environment Agency was involved in works at this site, although it should be noted that the EA was not formed until 1996 – this may therefore be a reference to a predecessor organization. We would anticipate that the local authority would hold records of any requirements arising from the development of the Red House Gardens site on the relevant planning application file…

… noting that Bradford drainage department (as Lead Local Flood Authority) has considered and commented on the further information and reports that have been submitted, we can confirm that we have no further evidence regarding flood risk at this location that would add to the consideration of flood risk in the determination of this planning application."

13. Following this correspondence it is clear that the claimant's solicitors provided further information to the Environment Agency and engaged in a dialogue with them about the appropriateness of their consultation. The Environment Agency then corresponded with the Council again on 21^st November 2014. Within that letter, having outlined the further interaction which they had had with the claimant's solicitors, they provided an updated response recommendation in the following terms:

"Environment Agency updated response recommendation

We have considered the detailed assessment of the drainage characteristics of the application site and the potential flood risks to and resulting from the development which has been submitted in support of this application. We acknowledge that the assessment includes consideration of information and reports provided by local residents.

We are satisfied that the flood risk assessment adequately addresses both flood risk and surface water management. We can confirm that we concur with the conclusions which the LLFA officers have already made in respect of the flood risk assessment. We point out that as a matter of principle the LFFA officers are best placed to advise you on the flood risk and surface management issues arising in connection with the application as such matters are within Bradford Council's remit as the LLFA.

We consider that Bradford Council should ensure that the mitigation measures detailed in the flood risk assessment are implemented and secured for the lifetime of the development. We recommend that these measures are secured through the inclusion of a planning condition on any planning permission. If the implementation of the mitigation measures are not secured, our position would be one of objection on the flood risk grounds."

14. The Environment Agency then went on to describe conditions which they wished to see imposed on the consent so as to ensure that flood risk issues were properly dealt with.
15. On 2^nd April 2015, following completion of the section 106 obligation on 31^st March 2015, planning permission was granted subject to the following conditions:

"2. No development shall take place until full details and calculations of the proposed means of disposal of foul and surface water drainage, have been submitted to and approved by the Local Planning Authority.

Reason: To ensure the application site is properly drained.

3. No development shall take place until details of how the development will cater for flood waters generated within the existing watercourse and wider catchment is submitted and approved by the LPA.

Reason: In the interests of flood protection.

4. The total combined surface water flows from the development draining to the existing watercourse on the submitted drawing 6984/Fig 3. shall be restricted to a peak flow of 5 litres per second. Furthermore, the developer should submit proposals to mitigate damage to the development, or residence downstream of it, should exceedence of the system occur.

Reason: In the interests of flood protection

5. The development permitted by this planning permission shall be carried out in accordance with the approved Flood Risk Assessment (FRA) dated 28^th March 2014 revision C and associated drawing Schematic for External Works (no 6984 Fig5 RevA) with the following mitigation measures detailed within the FRA:

1. Limiting the surface water run-off generated by the up to and including 1 in 100 year critical storm so that it will not exceed the run-off from the undeveloped site or increase the risk of flooding off-site. Run off rates should be finalised with the lead local flood authority;

2. Finished floor levels of new dwellings are set no lower than 148.3 metres AOD; and

3. Provision of Flood Storage Areas and swales.

The mitigation measures shall be fully implemented prior to occupation of any dwelling comprised in the development hereby approved and shall be maintained for the life time of the development.

Reason: To prevent flooding by ensuring the satisfactory storage/disposal of surface water from the site; and to reduce the risk of flooding to the proposed development and future occupants; and to provide maintenance access to the culvert and prevent compromise of the culvert structure.

6. No development shall take place until details for proposals for dealing with any existing watercourses, culverts, land drains etc encountered during the works are submitted to and approved in writing by the LPA. The development to be carried out in accordance with the approved details.

Reason: In the interest of the protection of the watercourse.

…

17. No development shall take place until full details and calculations of the proposed means of disposal of foul and surface water drainage, have been submitted to and approved by the LPA. The development to be carried out in accordance with the approved details.

Reason: In the interests of the drainage of the site."

16. The decision of the Council to grant planning permission is the subject of the first judicial review which is before me ("JR1"). Following the grant of planning permission on 3^rd August 2015 the interested party applied to the defendant for the discharge of conditions 2, 3, 5, 6 and 17. Details were provided to the defendant in order to satisfy the requirements of the conditions prior to the commencement of development. In the original submission made of details to discharge drainage conditions 2, 3, 5, 6 and 17 the interested party had recalculated the drainage requirement for the underground storage system reducing the pass forward flow from the 5 l/sec deployed in the FDA to a value of 4.45 l/sec. Subsequently in a further revised set of details to discharge those conditions the pass forward flow was adjusted down further to a value of 3.5 l/sec. The final version of the "Drainage Notes" submitted to satisfy the requirements of the conditions provided as follows:

"The detailed drainage design for the development has been prepared in accordance with the approved Flooding and Drainage assessment report [revC] for the site.

With reference to the Flooding and Drainage Assessment.

In order to reduce the volume of discharge from the development drainage system in a 6 hour period by the 32.4m³ 'exceedence' (ie to maintain the calculated volumetric discharge from the site to 172.2m³) the discharge rate form (sic) the storm water system has been reduced from 5.0l/s to 3.5l/s [ie (5.0 x 60 x 60 x 6 = 108.0m³) – (3.5 x 60 x 60 x 6 = 75.6m³) = 108.0 – 75.6 = 32.4m³].

The final detailed design of the surface water drainage system, including the stormwater storage has been undertaken using Windes drainage software. A storm return period of 1:100 has been used for storms between 15 and 10800 minutes for both summer and winter events. A 30% allowance for climate change has been included within the calculations.

Calculations for all storms have been submitted for approval.

The proposed drainage system is indicated on drawing 6984/010revC."

17. Further in relation to the discharge of draining condition 6 a statement was provided on behalf of the interested party in the following terms:

"Should any unrecorded watercourses, culverts or land drains etc. be exposed during the works the Local Panning Authority will be notified in writing immediately and operations on the affected part of the site ceased until a temporary diversion to the water course is put in place.

It would be the intention to retain the watercourse, culverts or land drains in place but if the watercourses, culverts or land drains are below a proposed property it would be the intention to divert the watercourse, culverts or land drain around the property in question. All watercourse, culverts or land drains would be piped directly to the water course that crosses the site to avoid potential accumulations of water in garden areas.

An amended drainage drawing would be submitted to the Local Planning Authority to obtain the necessary consents prior to works being undertaken on the site."

18. In evidence lodged on behalf of both the defendant and the interested party in these proceedings the court has been advised that there are differences between the drawing 6984/Fig.5 RevA which was submitted with the FDA, and drawing 6984/010 RevC which was the detailed design drawing submitted for the purpose of discharging the conditions. The differences between the two drawings include, in addition to a different specification for the hydro-brake to reduce the pass forward flow to 3.5 l/sec rather than 5 l/sec, an alteration to the definition of the boundaries of one of the above ground storage areas. That redefinition is said to have only "a neutral effect on storage volumes". In respect of the underground conveyance and storage system for surface water arising from the impermeable elements of the development there are changes to both the lengths and the profile of the culvert or pipes involved in its construction, such that the storage volume which it would provide in the version contained in drawing 6984/010 RevC is 196.1m³ rather than the 199.2m³ on drawing 6984/Fig.5 RevA. This change in the storage volume is said in the evidence of Mr Lawrence on behalf of the interested party to reflect the more detailed calculations which were undertaken in the preparation of the detailed scheme to discharge the conditions, and also said to be consistent with the minor reductions in calculated volume which arise from the more detailed work which is undertaken in the design of a full surface water storage system.
19. On 8^th October 2015 Mr Norfolk, the defendant's senior drainage engineer, provided his assessment of the proposals to discharge the conditions in the following terms:

"The principles and arrangement of the foul and surface water drainage scheme are acceptable. The submitted calculations show the proposed surface water system does not flood and is therefore adequately designed to cater for all storm events…

Conditions 2 and 17 are therefore recommended to be discharged…

Within the Flooding and Drainage assessment dated 28 March 2014a hydraulic model of the existing watercourse that passes through the site was included. Within these modelled results it was shown that the existing site, pre development, during an 1:100year rainfall event, flooded to a level of 147.70 equating to a volume of 216.3m³. The report also included a scenario for the proposed site levels presented on drawing 6984/Fig4 Flood Compensation Areas, which would provide a total volume of storage equating to 324m³ in dealing with the existing flood volumes. Drawings 6984/100 Rev A, 6984/101 – and 6984/102 – confirm that the suggested levels in the report are to be incorporated into the proposals thus ensuring the proposed site includes approximately 50% more storage in catering for flood waters generated by the watercourse. Furthermore, The sites existing 1:100 year greenfield discharge rate is calculated as 24.2 litres/second/hectare. This would give a discharge volume of 24.2 x 60 x 60 x 6 x 1.0 = 522.7m³ from the undeveloped site in a 1:100 year 6 hour event. For the developed areas of the site (3720m²) the greenfield runoff equates to an existing volumetric discharge for the 1:100 year 6 hour storm event of 24.2 x 60 x60 x 6 x 0.372 = 194.5m³ However, the proposed discharge rate from the developed areas of the site will be restricted to 3.5litres/second which equates to a volumetric discharge from the 1:100 year 6 hour event of 3.5 x 60 x 60 x 6 = 75.6m³. Therefore the proposed volume of discharge is less than the pre development situation thus showing the development runoff will not take up space in the 50% increase in storage provision for the watercourse.

Condition 3 is therefore recommended to be discharged…

Part 1 of condition 5 relates to the limiting discharge rate of surface water runoff from the development. The existing greenfield runoff rate for the site has been correctly calculated using the IH124 method as, 1:1 year = 8.2litres/second/hectare and 1:100 year = 24.2 litres/second/hectare. As per the assessment in discharging condition 3, The sites existing 1:100 year greenfield discharge rate is calculated as 24.2 litres/second/hectare. This would give a discharge volume of volume of 24.2 x 60 x 60 x 6 x 1.0 = 522.7m³ from the undeveloped site in a 1:100 year 6 hour event. For the developed areas of the site (3720m²) the greenfield runoff equates to an existing volumetric discharge for the 1:100 year 6 hour storm event of 24.2 x 60 x 60 x 6 x 0.372 = 194.5m³ However, the proposed discharge rate from the developed areas of the site will be restricted to 3.5 litres/second which equates to a volumetric discharge from the 1:100 year 6 hour event of 3.5 x 60 x 60 x 6 = 75.6m³. Therefore the proposed volume of discharge is less than the pre development situation thus showing the agreed discharge rate is acceptable in discharging part 1 of condition 5…

Drawings 6984/100 Rev A, 6984/101 – and 6984/102 – confirm that the finished external levels shown on the drawing 6984/Fig4 Flood Compensation Areas thus indicating the site provides the necessary provision of flood storage areas and swales recommended within the Flooding and Drainage Assessment dated 28^th March 2014 and as a result Part 3 of condition 5 is satisfied.

Condition 5 is therefore recommended to be discharged…

The information contained within the above documentation describes the applicant's intentions in dealing with any unknown watercourse, land drains or culverts in a manner that would ensure that flood risk during the development lifetime would not be increased. The strategy in the statement is considered acceptable to recommend the discharge of condition number 6."

20. On 15^th October 2015 the details submitted to discharge conditions 2, 3, 5, 6 and 17 were approved by the defendant. The decision to discharge these conditions is the subject of the second judicial review which is before the court ("JR2").

Policy and guidance

21. Whilst a wide range of policy material was placed before the court the key policies for the purposes of determining the issues which arise in this case are contained within the Framework in particular at paragraphs 100, 101 and 103 which provide as follows:

"100. Inappropriate development in areas at risk of flooding should be avoided by directing development away from areas at highest risk, but where development is necessary, making it safe without increasing flood risk elsewhere. Local Plans should be supported by Strategic Flood Risk Assessment and develop policies to manage flood risk from all sources, taking account of advice from the Environment Agency and other relevant flood risk management bodies, such as lead local flood authorities and internal drainage boards. Local Plans should apply a sequential, risk-based approach to the location of development to avoid where possible flood risk to people and property and manage any residual risk, taking account of the impacts of climate change, by:

•     applying the Sequential Test;

•     if necessary, applying the Exception Test;

•     safeguarding land from development that is required for current and future flood management;

•     using opportunities offered by new development to reduce the causes and impacts of flooding; and

•     where climate change is expected to increase flood risk so that some existing development may not be sustainable in the long-term, seeking opportunities to facilitate the relocation of development, including housing, to more sustainable locations.

101. The aim of the Sequential Test is to steer new development to areas with the lowest probability of flooding. Development should not be allocated or permitted if there are reasonably available sites appropriate for the proposed development in areas with a lower probability of flooding. The Strategic Flood Risk Assessment will provide the basis for applying this test. A sequential approach should be used in areas known to be at risk from any form of flooding…

103. When determining planning applications, local planning authorities should ensure flood risk is not increased elsewhere and only consider development appropriate in areas at risk of flooding where, informed by a site-specific flood risk assessment following the Sequential Test, and if required the Exception Test, it can be demonstrated that:

•     within the site, the most vulnerable development is located in areas of lowest flood risk unless there are overriding reasons to prefer a different location; and

•     development is appropriately flood resilient and resistant, including safe access and escape routes where required, and that any residual risk can be safely managed, including by emergency planning; and it gives priority to the use of sustainable drainage systems."

22. Guidance is provided in relation to the implementation of the Framework in the Planning Practice Guidance (the "PPG"). In particular the claimant draws attention to the guidance at ID7-050-20140306 which provides as follows:

"What are the opportunities for reducing flood risk overall?

Local authorities and developers should seek opportunities to reduce the overall level of flood risk in the area and beyond. This can be achieved, for instance, through the layout and form of development, including green infrastructure and the appropriate application of sustainable drainage systems through safeguarding land for flood risk management, or where appropriate, through designing off-site works required to protect and support development in ways that benefit the area more generally."

Grounds and procedure

23. As set out above there are two actions for judicial review before the court. The first is in relation to the planning permission that was granted by the defendant. Permission to apply for judicial review in respect of that action was given by Patterson J on 20^th June 2015 on two grounds that are set out below. By the time that claim came to be heard on 27^th November 2015, the defendant had undertaken the discharge of conditions by the approval of the details which have been specified above. In the light of the interrelationship between the challenges to the planning permission and the discharge of the conditions the claimant launched a judicial review against that approval on 23^rd November 2015. With the agreement of the parties, JR2 in relation to the discharge of conditions was joined with JR1, and a rolled-up hearing was ordered in relation to it which occurred on 8^th January 2016. Thus this judgment deals with the substantive merits of the two grounds arising in JR1, and the determination of the question of permission together with, if granted, the substantive merits of the three grounds comprised within JR2.
24. So far as JR1 is concerned the two grounds which were granted permission are as follows. Ground 1 is the contention that the defendant misinterpreted the relevant policies of the Framework and the PPG in relation to issues of flooding. The claimant contends that the approach of the defendant, which was to base their conclusion on flooding issues solely upon the question of whether or not the development proposals led to an increase in an existing flood risk, was misconceived and a misunderstanding of the relevant policy. That unlawful misinterpretation meant that the flooding issue that was placed before the members was illegitimately confined to an examination of simply whether or not the development led to an increase in existing flood risk. What was left out of account when the policy was examined was the issue which should have arisen had the policy been properly interpreted, of whether or not the development should be required to take opportunities to reduce flood risk rather than simply leaving that risk unaffected.
25. Ground 2 under JR1 is based on the contention that members were misled when they were advised that the development proposals would add a storage volume of more than 50% in addition to that presently available at the site. The claimant contends that this claim was incorrect. It left out of account the additional requirement for 32.4m³ of storage that arose from the FDA identifying an increase when calculations were undertaken as to the extent of surface water discharge arising from the impermeable parts of the site. Thus the claimant contends that members were significantly misled by the committee report about the extent of the alleged benefits from the surface water drainage provision that was to be made by the development. It was submitted that this amounted to a legal error.
26. JR1 is linked to JR2 through JR1's Ground 2, since both the defendant and the interested party contend that as a consequence of the requirements of condition 5, and in particular the additional control of runoff or pass forward rates which it provides, the 50% uplift or increase in flood storage over the existing provision at the site can and would be retained. Thus whilst they contend that the committee were not misled in the way described by the claimant for reasons which are explored in greater detail below, it is contended that in any event the issue of the extent of increase in flood storage is safeguarded through the provision of the details which were required by condition 5. Furthermore, in the light of the details which were in fact provided by the interested party, the defendants contend that the details which were approved did ensure that there was a 50% increase in the existing storage on site. It was against the backdrop of these contentions that the claimant raised its concerns in respect of the approval of the matters subject to conditions in JR2.
27. As indicated above JR2 proceeds on the basis of three Grounds. Ground 1 relates to condition 5, and it is the submission that the details which were approved were not "in accordance with the approved Flood Risk Assessment (FRA) dated 28^th March 2014 revision c and associated drawing Schematic for External Works (no 8985 Fig.5 RevA)". In particular, for instance, a different pass forward or runoff flow rate has been endorsed in the discharge of the details, and the underground storage volume which is proposed has been changed. Further there are changes to the above ground storage areas from those that had been provided on the drawing identified in the condition. The approval of these details is therefore, it is submitted, based on a flawed understanding of the requirements of condition 5, which if properly interpreted required the details which were being approved to be the same as those which had been approved in the FDA, and identical to those which had been proposed in drawing 8984 Fig.5 RevA. Thus the condition had not been properly interpreted as to its correct legal effect and therefore the discharge of the details was unlawful.
28. Ground 2 of JR2 relates to condition six and is the concern that the details which have been approved will not provide protection to the existing watercourse from additional discharge of water into it thereby affecting the calculations and assumptions of the FDA as to the impact of the development on flood risk. The claimant contends that it cannot be assumed that all potential watercourses, culverts or land drains which might be discovered within the site upon detailed site works occurring are currently draining into the existing watercourse, as appears to be the assumption underpinning the details which have been approved. The details afford the opportunity for unknown watercourses, culverts or land drains when they are unearthed to be connected into the existing watercourse providing further loading of it which would undermine the calculations and assumptions of the FRA. Further, concern was expressed by the claimant in oral argument that the defendant's assumption that it would get further details identifying the treatment of any unidentified watercourse, culverts or land drains was misplaced and could not be assured by the details which had been approved. Thus, again, the details were unlawful and based upon an unlawful misinterpretation of the condition.
29. Ground 3 of JR2 is based upon condition 3 which, it will be recalled, calls for details of how the development will cater for flood water generated not just within the existing watercourse but also within the wider catchment. The claimant submits that no assessment of the impact on the wider catchment of the development proposals and their implications for the wider catchment is evident from Mr Norfolk's discussion of the merits of the details. Thus there is no evidence of any assessment as required by the condition of the impact on the wider catchment, and therefore there has either been a failure to take account of these issues as material considerations, or an unlawful misinterpretation of the requirements of the conditions in its discharge. In response to the contention of the defendant and the interested party that in fact any issues associated with the wider catchment had already been addressed in the FDA the claimant responds by simply pointing out that the discussion in the record of the discharge of the condition does not contain any evidence of the question of the wider catchment being addressed. Ultimately the claimant submits that both conditions 3 and 6 are related, and required full additional details of both how undiscovered watercourses, culverts or land drains were to be dealt with and how the impacts upon the wider catchment were to be addressed so as to ensure the protection of the existing watercourse. The failure to secure the provision of such details represents an unlawful interpretation of those conditions and a failure to properly apply their requirements.

The Law

30. The discretion to grant planning permission is provided by section 70 of the Town and Country Planning Act 1990 and further described by the provisions of section 38(6) of the Planning and Compulsory Purchase Act 2004 (see below). Section 72 of the 1990 Act permits the local planning authority to impose conditions on the grant of planning permission. Generally speaking a challenge to the issue of a planning consent by way of judicial review is brought on the basis of the contention that there has been a breach of the Wednesbury principles, or that there has been a failure in the procedural requirements of the law framing the requirements of the grant of planning permission. An attack based on Wednesbury principles will contend that the local planning authority has failed to have regard to material considerations or alternatively has taken into account immaterial considerations, or arrived at a decision which no reasonable planning authority could have reached. The procedural requirements in relation to the grant of planning permission can relate to the broader common law requirements of fairness, or to specific steps that need to be taken before planning permission should be granted in relevant procedural regulations such as, for example, the consideration of whether an Environmental Impact Assessment is required.
31. The provisions of section 38(6) are as follows:

"38(6) If regard is to be had to the development plan for the purpose of any determination to be made under the planning Acts the determination must be made in accordance with the plan unless material considerations indicate otherwise."

32. It will be seen from the approach which is required by this legislative provision that it necessarily involves the application of development plan policy. It is also the case that in very many, if not all, planning decisions national planning policy in the form of the Framework will be a material consideration which also needs to be taken into account. The interpretation of planning policy, as opposed to its application and the judgments which may be involved in applying it, is a matter for the court: see Tesco Stores Limited v Dundee City Council [2012] UKSC 13.
33. As in many cases, the application for planning permission in this case was determined by the committee with the benefit of an officer's report setting out the material considerations, the planning policies and the officer's assessment of the planning merits. The relevant principles in relation to the approach to a legal appraisal of an officer's report were aptly captured by Hickinbottom J in the case of R (on the application of Zurich Assurance Limited T/A Threadneedle Property Investments) v North Lincolnshire Council and another [2012] EWHC 3708 (Admin) at paragraph 15 of his judgment as follows:

"15. Each local planning authority delegates its planning functions to a planning committee, which acts on the basis of information provided by case officers in the form of a report. Such a report usually also includes a recommendation as to how the application should be dealt with. With regard to such reports:

i) In the absence of contrary evidence, it is a reasonable inference that members of the planning committee follow the reasoning of the report, particularly where a recommendation is adopted.

ii) When challenged, such reports are not to be subjected to the same exegesis that might be appropriate for the interpretation of a statute: what is required is a fair reading of the report as a whole. Consequently:

"[A]n application for judicial review based on criticisms of the planning officer's report will not normally begin to merit consideration unless the overall effect of the report significantly misleads the committee about material matters which thereafter are left uncorrected at the meeting of the planning committee before the relevant decision is taken" (Oxton Farms, Samuel Smiths Old Brewery (Tadcaster) v Selby District Council (18 April1997) 1997 WL 1106106, per Judge LJ as he then was).

iii) In construing reports, it has to be borne in mind that they are addressed to a "knowledgeable readership", including council members "who, by virtue of that membership, may be expected to have a substantial local and background knowledge" (R v Mendip District Council ex parte Fabre (2000) 80 P & CR 500, per Sullivan J as he then was). That background knowledge includes "a working knowledge of the statutory test" for determination of a planning application (Oxton Farms, per Pill LJ)."

34. The law in relation to the interpretation of planning conditions has recently been considered by the Supreme Court in the decision of Trump International Golf Club Scotland Limited and another v The Scottish Ministers [2015] UKSC 74. Both Lord Hodge JSC, giving the leading judgment in the Supreme Court and also Lord Carnwath JSC in a concurring judgment, were at pains to point out that the approach to the construction and interpretation of planning conditions is no different from that which should be undertaken in relation to any legal document, and that there are not particular canons of construction for planning conditions. Lord Hodge observed as follows:

"34. When the court is concerned with the interpretation of words in a condition in a public document such as a section 36 consent, it asks itself what a reasonable reader would understand the words to mean when reading the condition in the context of the other conditions and of the consent as a whole. This is an objective exercise in which the court will have regard to the natural and ordinary meaning of the relevant words, the overall purpose of the consent, any other conditions which cast light on the purpose of the relevant words, and common sense. Whether the court may also look at other documents that are connected with the application for the consent or are referred to in the consent will depend on the circumstances of the case, in particular the wording of the document that it is interpreting. Other documents may be relevant if they are incorporated into the consent by reference… or there is an ambiguity in the consent, which can be resolved, for example, by considering the application for consent.

35. Interpretation is not the same as the implication of terms. Interpretation of the words of a document is the precursor of implication. It forms the context in which the law may have to imply terms into a document, where the court concludes from its interpretation of the words used in the document that it must have been intended that the document would have a certain effect, although the words to give it that effect are absent. See the decision of the Privy Council in Attorney General of Belize v Belize Telecom Ltd [2009] 1 WLR 1988 per Lord Hoffmann at paras 16 to 24 as explained by this court in Marks & Spencer plc v BNP Paribas Securities Trust Company (Jersey) Ltd [2015] UKSC 71, per Lord Neuberger at paras 22 to 30. While the court will, understandably, exercise great restraint in implying terms into public documents which have criminal sanctions, I see no principled reason for excluding implication altogether.

36. In my view assertions, such as are found in Trustees of the Walton-on-Thames Charities v Walton and Weybridge Urban District Council (1970) 21 P & CR 411, Salmon LJ at p 418 and Widgery LJ at p 420, and in the Sevenoaks District Council case (above), Sullivan J at para 45, that there can never be an implied condition in a planning permission are too absolute."

35. Lord Carnwath JSC expressed his overall conclusions in paragraph 66 of his judgment in the following terms:

"66. … As will have become apparent, however, and in agreement also with Lord Hodge, I do not think it is right to regard the process of interpreting a planning permission as differing materially from that appropriate to other legal documents. As has been seen, that was not how it was regarded by Lord Denning in Fawcett. Any such document of course must be interpreted in its particular legal and factual context. One aspect of that context is that a planning permission is a public document which may be relied on by parties unrelated to those originally involved. (Similar considerations may apply to other forms of legal document, for example leases which may need to be interpreted many years, or decades, after the original parties have disappeared or ceased to have any interest.) It must also be borne in mind that planning conditions may be used to support criminal proceedings. Those are good reasons for a relatively cautious approach, for example in the well-established rules limiting the categories of documents which may be used in interpreting a planning permission (helpfully summarised in the judgment of Keene J in the Shepway case at pp 19-20). But such considerations arise from the legal framework within which planning permissions are granted. They do not require the adoption of a completely different approach to their interpretation."

Conclusions

36. As set out above the case advanced on behalf of the claimant was that the correct interpretation of paragraphs 100, 101 and 103 of the Framework, when read in the context of the PPG, was that policy required opportunities to be taken to reduce existing flood risk, and that the test was not limited to simply examining whether or not any existing flood risk would be exacerbated or whether development was being permitted in an area at risk of flooding. Reliance is placed in particular on the PPG in the extract quoted above which emphasises that local authorities and developers "should seek opportunities to reduce the overall level of flood risk in the area and beyond." The claimant draws attention to the fact that those making representations upon the application drew attention to the concern that the interested party was not seeking or taking any opportunities to reduce the existing flood risk evident at the application site. Indeed the advice to the members was cast in a form which effectively excluded the need for the committee to consider whether there were any opportunities to reduce flood risk and as a consequence the members' approach was infected with an illegal misinterpretation of the relevant policy, and therefore the decision resulted from a misdirection in law as to the appropriate policy test.
37. Although in its written case on this point the defendant seeks to emphasise that there is in law no requirement for an application to achieve betterment, and the mere fact that a better proposal than the one comprised in the application before the decision-maker could be conceived of is not in and of itself a reason for refusing an otherwise acceptable application, in my view that general proposition (whilst true) is of limited assistance in the present case. There is no reason why a policy either in a development plan or the Framework could not seek to deploy development in order to achieve betterment or advantages in respect of any environmental consideration. Indeed it will very often be the case that the purpose of producing a policy will be to ensure that in appropriate respects contemplated development brings about an improvement to the built or natural environment alongside addressing economic or community needs for particular forms of development. Thus whilst as a general proposition, and in the absence of any particular policy, it is the case that the fact that a more advantageous proposal to that which is being considered is not a reason for refusing an otherwise acceptable development, if there is a specific policy which engages with the prospect of securing environmental improvement then that policy needs to be fulfilled if a proposal is to be found to be in accordance with the policy.
38. The real question in this case is whether or not the Framework and the PPG require, in the development control context, a proposal to seek out and provide opportunities to reduce flood risk.
39. In my view it is clear when reading paragraphs 100, 101 and 103 together that they provide different tests and objectives when considering the determination of planning applications (or decision-making) from occasions when the preparation of local plans is being undertaken (or plan-making). It is clear from the third sentence of paragraph 100 that when plan-making, one of the objectives in determining where development should be located is "using opportunities offered by new development to reduce the causes and impact of flooding". This is identified by the policy as one of the factors which must be borne in mind when meeting development needs. Thus when considering and preparing local plans the seeking out of opportunities to reduce the causes and impact of flooding is clearly an objective that the policy requires to be examined, and the failure to take such opportunities when they are available would be a breach of the policy.
40. By contrast it is equally clear in my view from the three paragraphs in point, and in particular from the specific policy in paragraph 103, that in relation to the task of determining planning applications an approach is adopted which does not set as a policy test the requirement to seek out opportunities to reduce the causes and impacts of flooding. The opening clauses of paragraph 103 make clear that for the purposes of planning applications the test is to ensure "flood risk is not increased elsewhere", and where development is contemplated in areas which are at risk of flooding the policy requires the application of the sequential test and, if necessary, the exception test.
41. The paragraph of the PPG to which the claimant makes reference is, firstly, obviously subservient to the policy for which it provides practice guidance. Thus if, as I am satisfied, the Framework does not include a test when decision-making which requires the seeking out of opportunities to reduce the causes and impacts of flooding, the text within the PPG could not override that reading of the primary document. In any event, and secondly, the text from the PPG upon which the claimant relies is of generic or overarching application and does not provide an additional gloss on the Framework's separation of policy requirements for plan-making and decision-taking. The text does not undermine the proper interpretation of paragraphs 100, 101 and 103 of the Framework to provide for separate tests for plan making and decision taking. That is not to say that the observation in the PPG could not be pertinent in the decision-making context. No doubt if in the decision-making context a proposal were to offer as a benefit the reduction of flood risk in the area that would be a positive material consideration which would need to be borne in mind in the support of the grant of planning permission. There is a difference between that approach and the suggestion that, notwithstanding the clear terms of paragraph 103 of the Framework, there is nonetheless a policy requirement that development proposals seek out and provide benefits in terms of flood risks in the area and beyond. In short, whilst it is not a breach of paragraphs 100, 101 and in particular 103 of the Framework for a proposal not to seek out or secure opportunities to reduce flood risk, if a development proposal offers such a benefit then plainly that would be a positive factor in the planning balance weighing in favour of the grant of planning permission.
42. It follows that I am unable to accept the claimant's contention that there was a misinterpretation or misapplication of the Framework's policy in the present case. It is of course, to say the least, unfortunate that the phrase "[WHAT LEGISLATION?]" appeared in the officer's report. Apparently this was a legacy of an earlier draft of the report which had been overlooked and should have been removed. What counts, however, is that the identification of the proposal as one which was "to develop the site so as not to increase flood risk" was an approach faithful to a correct understanding of the relevant paragraphs of the Framework and in particular paragraph 103. I am therefore satisfied that there is no substance in Ground 1 of JR1.
43. In my view it is convenient to deal with the grounds in relation to JR2, and in particular Ground 1 of that case, prior to considering the matters raised under JR1 Ground 2. As set out above they are interrelated in the sense that the defendant and the interested party contend that even had it been inaccurate at the time of the committee report to have described the proposals as giving rise to an increase in 50% over existing flood storage, the nature of the details which have been approved under the discharge of the condition meet that suggestion in any event.
44. Turning therefore to JR 2 Ground 1 it is the claimant's contention that the requirement of condition 5 that the development "be carried out in accordance with the approved Flood Risk Assessment (FRA) dated 28^th March 2014 RevC and associated drawing Schematic for External Works (no 6984 RevA)" are clear and unambiguous and require the development to be carried out with accordance to the details which were specified in the FDA and the identified drawing. In particular there were particular features of the FDA and that drawing that, pursuant to the condition, were bound to be adopted and delivered by the details. In particular the underground storage of 199.2m³ was required, as was the discharge flow or pass forward rate of 5 l/sec on which the calculations contained within the FDA had been based. The approved details could not comply with the conditions, it was submitted, on the basis that they were founded upon a different discharge rate, alternative calculations and amended details as to the storage volumes. As such the Council could not lawfully have approved those details as they were inconsistent with a proper understanding as to what was required by the condition.
45. Adopting the approach set out in Trump it is necessary to start the process of interpreting the words of condition 5 on the basis of what a reasonable reader would understand them to mean, reading the condition in context and bearing in mind that it is a public document. It is in particular important in my judgment to read the condition as a whole. The focus of the claimant's submissions are on the introductory paragraph, but as the defendant and interested party point out that is a paragraph which induces the three further elements of the condition set out below it. So far as runoff rates or discharge flow or pass forward rates are concerned condition 5(1) requires surface water runoff generated by the up to and including 1:100 critical storm to be limited so that it would not exceed runoff from the undeveloped site or increase the risk of offsite flooding. Importantly it provides that: "runoff rates should be finalised with the lead local flood authority", in this case the defendant. Thus the condition itself specifically contemplates that there may very well be alterations to the runoff rates in the final details of the development which are implemented following the discharge of conditions. Furthermore condition 5(3) requires the "provision of flood storage areas and swales" and contemplates the provision of detailed proposals in respect of them.
46. Whilst it is, of course, necessary to note that the condition says that the three subparagraphs to condition 5 relate to "mitigation measures detailed within the FRA", in that in particular part 5(1) of the condition does not require adherence to the values contained within the FDA it is not possible in my view to interpret condition 5 as requiring identical mitigation measures to those set out in the FDA as opposed to mitigation measures of the kind, or as identified in principle, within the FDA. If the proposals were going to be exactly the same as the FDA there would be no need, for instance, to provide for further finalising of runoff rates. Thus I am unable to accept the claimant's submission that the wording of the condition required identical provisions to those contained within the FDA to be proposed within the details required through the discharge of conditions. The words of the condition itself in my view contemplate the alteration of specific values within the FDA, albeit in the context of the framework of the drainage principles set out within that document.
47. This interpretation of the wording of condition 5 is not surprising when it is read in the context of the other conditions. Conditions 2 and 17 required further details and calculations in relation to the proposals for surface water drainage. Thus the scheme of the conditions contemplated further details and additional fine-tuning of the surface water drainage proposals as the project progressed into the detailed engineering design solution for this aspect of the development. It will be unsurprising, and indeed the conditions contemplate, the alteration of the fine detail of the calculations and design in consequence of undertaking further examination of the implementation of the permission.
48. Turning to the identification of the drawing within condition 5 in my view the status of that drawing within the FDA and conditions is clear. It is a "schematic" drawing. It is therefore a drawing which indicates the principles of how, amongst other matters, satisfactory surface water drainage of the developed site is to be accomplished but it is not intended to be a detailed engineering drawing for the purpose of actually implementing the consent. The use of the language "schematic" contemplates that further detailed work would be provided, and that it could be expected that the detail of what was depicted on the drawing (as opposed to the principles of the solution which it described) would alter prior to the development actually being commenced. The conditions provide the medium for the approval by the Council of that further necessary and important detailed work.
49. It follows therefore that I am not satisfied that there was any misdirection or error in the approval of the details under condition 5 (and for that matter conditions 2 and 17). The details reflected the kind of additional work that would be necessary within the overall framework of the principles set out in the FDA.
50. Turning to JR2 Ground 2 in my view there is simply no substance in the claimant's concerns. The details which have been approved by the defendant in response to condition 6 do not disclose any error of law. On the basis of the present levels of the site, and what is known about the current way in which the watercourse runs through the site, it was an entirely appropriate working assumption that any unknown watercourses, culverts or land drains which might be discovered during the course of implementing the development would presently be draining into the watercourse crossing the site, and would therefore be part and parcel of the waters generated within that watercourse. Whilst the claimant raises the concern that there might be some unknown watercourse, culvert or land drain which does not accord with that working assumption discovered during the course of the works, the details which have been approved then require the submission of an amended drainage drawing to the defendant in order for necessary consent to be obtained prior to any further drainage work being undertaken. Thus the fear that an unknown watercourse not presently discharging into the watercourse crossing the site might be diverted so as to further load the existing watercourse is one which, however unlikely, is guarded against by the final clause of the discharge. I do not consider that the claimant's case in relation to this Ground is arguable and I refuse permission for it and dismiss it.
51. Turning to JR2 Ground 3 I have again formed the view that the contentions under this Ground are not arguable. It is true that in Mr Norfolk's memo providing his reasoning for the discharge of condition 3 he does not specifically identify how the development will cater for flood waters generated within the wider catchment. However, he specifically notes that in determining his recommendation he has had regard to the FDA. Within the FDA, as set out above, there is a consideration of the wider catchment and the application site's relationship to it, in particular in the context of the existing watercourse. In the light of that information the focus within Mr Norfolk's reasoning upon the existing watercourse, as it was in effect a feature which formed a part of the wider catchment within the application site, was one which was entirely reasonable and appropriate. Having reached the conclusions which he did on the basis of the technical material the considerations of the wider catchment had been addressed as part and parcel of the appraisal of the site itself. I therefore do not consider that there is any arguable error of law in the approach which he took.
52. To summarise therefore in relation to JR2 whilst I am satisfied that Ground 1 is properly arguable, I have formed the view that on the merits it should be dismissed. Grounds 2 and 3 of JR2 are in my view unarguable, and permission should be refused.
53. That then brings me to the question of JR1 Ground 2. In both their written and oral submissions the defendant and the interested party respond to the claimant's contention that the advice to the members that "flood storage provided equates to 50% more than what the site currently provides to the catchment" was misleading, by contending that this reference was not a suggestion that there was a 50% increase in the net storage capacity of the site. Thus the existence of the 32.4m³ exceedance from the storm water storage capacity calculation, and the fact that it ate into the storage capacity of the site, was irrelevant to the claimant's proposition since the officer's observation was limited to the creation of the additional surface storage features.
54. I am bound to say that I found these contentions somewhat unconvincing. When reading a committee report, as set out above, it is necessary to take a practical and straightforward approach to what is written and what members are to understand from the terms of the report. The sentence in question is one that is expressed in simple terms and clearly tells members that the amount of flood water storage to be provided on the site will increase by 50%. Be that as it may, as the defendant and the interested party point out the reality is that the details which have been discharged in relation to conditions 2, 5 and 17 ensure that there would be a 50% increase in the site's storage capacity since the reduction in the pass forward flow ensures that there is no erosion of the flood storage available to the watercourse. The detail of this calculation is set out in the submission made by the interested party set out above and endorsed by Mr Norfolk's memo. It will be seen from the notes associated with the calculation that the reduction in the discharge rate has been to reduce the volume of discharge so as to maintain the calculated volumetric discharge from the site to a level which avoids the 32.4m³ exceedance arising. Mr Norfolk's conclusion is that "the proposed volume of discharge is less that the pre development situation thus showing the development runoff will not take up space in the 50% in storage provision for the watercourse". The accuracy of this statement and of the calculations has not been gainsaid by the claimant in its submissions in JR2. Thus the representation to the members taken on its face has been honoured in the provision of the details which have now been approved, and therefore any concern which the claimant might legitimately have had in respect of Ground 2 of JR1 has been overcome by the lawful discharge of conditions which in fact ensure that there is a 50% increase in storage provision for the watercourse.
55. As a consequence and for all of the reasons which I have set out above I am satisfied on analysis that the claims both in JR1 and JR2 should be dismissed.