Test Valley Borough Council – Northern Area Planning Committee – 10 July 2014

ITEM 13

APPLICATION NO. 14/00300/FULLN APPLICATION TYPE FULL APPLICATION - NORTH REGISTERED 10.02.2014 APPLICANT Lord Simon Tanlaw SITE Upper Mill House , Monxton, Andover, SP11 8AP, PROPOSAL The construction of a replacement weir AMENDMENTS Additional information received: 06.03.2014 07.03.2014 21.03.2014 09.05.2014 CASE OFFICER Miss Emma Jones

Background paper (Local Government Act 1972 Section 100D)

1.0 INTRODUCTION 1.1 The application is referred to the Northern Area Planning Committee at the request of a Local Ward Member due to the widespread interest in this matter.

2.0 SITE LOCATION AND DESCRIPTION 2.1 Upper Mill House is situated to the east of the village of Monxton. The existing weir to be replaced is situated to the west of the existing dwelling and its residential curtilage. The site of the proposed replacement weir lies just outside the boundary of the and Monxton Conservation Area.

3.0 PROPOSAL 3.1 The construction of a replacement weir.

3.2 The planning application proposes alterations to the existing weir that was constructed at the point where the Pillhill Brook branches away from the mill stream. The information supporting this planning application advises that prioritising flow into a single channel, the Mill Leat (watercourse running directly to the south of the dwelling at Upper Mill House), during low flows will make the Pilhill Brook (overflow carrier) more resilient in flood flows. The existing weir is notched to allow a small flow through into the overflow channel. Inspection of the site on the 4th December 2013 found that this small flow caused the overflow channel to run for approximately 50m before running dry. The existing weir is constructed from reclaimed flint, dressed stone, rubble, concrete bags, butyl liner and topsoil. The replacement weir will be constructed from reclaimed materials from the existing weir, plus the structure is to be constructed with geotextile supported with chestnut posts with a finish of imported clean gravel.

Test Valley Borough Council – Northern Area Planning Committee – 10 July 2014

The supporting information advises that the final height of the new weir will be constructed at a lower height than the existing line of bagwork which forms the existing weir crest. The existing bag height across the weir crest varies but the lowest point of the new weir will be approximately 50mm lower than the existing weir crest bag height and 100mm above the existing notched section. The new weir will pass more water in flood flows than the existing weir.

3.3 The additional information received on the 6, 7 and 21 March 2014 provides clarification on the heights of the proposed replacement weir in relation to the existing weir, and clarification on the sections provided on the originally submitted plans. The additional information from the applicants agent also sets out the following;

“I have been monitoring the situation with regard to the river level in relation to the upstream properties. Even with the unprecedented rainfall we have had recently, there was no repeat of the flooding of the upstream fields of last spring, which was alleviated at the time in a matter of hours, by cutting weed in the Mill Race (even though the weir had already been lowered), thus showing that particular flooding was not due to the weir height at that time, but due to the weed growth which was partially blocking the Mill Race downstream. This was observed by the Environment Agency on site, and by upstream property owners.

The conditions in the field upstream adjacent to the Southern Water pumping station seem to have nothing to do with the weir. Indeed, the river level adjacent to that field appears to be 450-600mm lower than the top of the river bank. This points to the flooding in that field being groundwater and sewage overflow.

The new weir is designed so that the greater the volume of flooding, the greater amount of water will flow over the weir into the old river course, and will be substantially more than has been allowed into the old river course during the last few months of exceptionally high rainfall.

The proposed weir height is to be a good 600mm lower than the original height of the weir as renovated by Mr Burgess.

It has been agreed with the Environment Agency that the Mill Race should be the primary water carrier. The Mill Race is better able to hold a flow in drier conditions than the old river course, which owing to locally lowered groundwater levels, results in it drying up every summer through to October/November. Since I have been re-involved with the site, I have observed a healthy trout population in the Mill Race, and seen water vole on several occasions and kingfishers regularly fly its length and fish from specially constructed perches. There is no loss of wildlife and the river valley within the property is being managed to the complete satisfaction of the Environment Agency and County Council Biodiversity officer.

The whole essence of having a weir is to ensure that there is a flow of water from the western end to the eastern end of the Upper Mill House property. Test Valley Borough Council – Northern Area Planning Committee – 10 July 2014

There is not enough flow in the Pillhill Brook to service both the Mill Race and old water course together. There is also not enough volume of water during the summer and early winter periods to preserve a flow in the old river course alone, owing to depleted ground water conditions. The river bed dries up, as it is much wider and the ground in the bed becomes porous. Even with a reasonable flow over the weir in December the water sank into the ground after flowing approximately 200m, leaving the main straight section of the river completely dry. Surely it is better, as has been agreed by most of the official bodies, to keep the primary flow in the Mill Race with an improved structure which will enable more water to overspill the weir in times of flood than at present.”

The relevant Parish Councils, neighbours and interested third parties were notified of these additional submissions on the 26 March 2014.

3.4 The additional information received on the 9 May 2014 provides a copy of the Flood Defence Consent which was issued by the Environment Agency on the 26 March 2014for the proposed development.

3.5 The application is accompanied by a Flood Risk Assessment (Cain Bio- Engineering Ltd January 2014) and a Method Statement (Cain Bio-Engineering January 2014).

4.0 HISTORY 4.1 13/01556/FULLN; Retrospective application - Construction of access bridge across the Pilhill Brook overflow carrier – Permission – 23.04.2014

5.0 CONSULTATIONS 5.1 Design and Conservation; No objection.

5.2 Ecology; No concerns over the potential for this proposal to adversely affect biodiversity. Until recently there was an existing weir in place, preventing water flow through the southern channel. This weir has been partially removed, allowing a proportion of water to flow along the southern arm of the stream before this re-joins some 360m to the east.

The proposed weir appears to be designed to avoid any significant reduction in water flow along the northern branch of the watercourse during normal flow levels, but to enable water to divert along the line of the southern watercourse as water levels rise. The proposal will not affect any statutory or non-statutory site for nature conservation, nor is it likely to affect any legally protected or notable species. By enabling the southern channel to take water, this is likely to increase the diversity of habitats present over that which is present at the moment and may thus result in a net gain to biodiversity.

5.3 Hampshire County Council as Lead Local Flood Authority; Hampshire County Council has no objection to the application which is also supported by a Flood Defence Consent from the Environment Agency.

Test Valley Borough Council – Northern Area Planning Committee – 10 July 2014

The Flood Risk Assessment indicates no increase of flood risk from the reconstruction of the weir. The new weir appears from the drawings submitted to allow a larger volume of water to pass over the weir at times of high flow in the river.

Currently, Hampshire County Council have received reports of sewerage flooding upstream of the weir caused by high ground water inundating the pumping station but no reports this winter (November 2013 to March 2014) of fluvial flooding in the location upstream of the weir as far as the Andover Road bridge.

In the interests of clarity, Hampshire County Council have received reports from a resident about fluvial flooding in the property upstream of the Andover Road bridge, the resident explained that this is caused by capacity of the Andover Road bridge.

In the reports of flooding received by Hampshire County Council, over the last 18 months, no evidence has been received of internal property flooding.

5.4 Environment Agency; No comments to make regarding the planning application.

6.0 REPRESENTATIONS Expired 09.04.2014 6.1 Abbotts Ann Parish Council; No objection.

6.2 Monxton Parish Council; Monxton PC objects to the application unless certain conditions are imposed and enforced;

1. The U-shaped design is changed to V-shaped and the depth of the weir is constructed such that sufficient water is allowed to flow down the Pill Brook river in the winter months to prevent flooding when levels are high. Conversely, during summer when water levels can be much reduced, the weir must be designed to allow enough water to go down the Pill Hill brook to allow fish life to continue in the original river course and maintain this very important asset for all aquatic species; 2. The proposed height of the weir is reduced so that the bottom of the weir is at the same depth as centre of the river bed: Note: the application proposed that the new ‘weir’ is increased in height by 100mm, which is effectively a higher dam, which has caused the flooding to the surrounding area last year and now this year; 3. The full flood risk assessment is produced for the upstream area i.e. Monxton Village: Note: The current application makes no mention of the risk of flooding to the surrounding area and the flood risk will be increased if the new weir is allowed to be raised. Test Valley Borough Council – Northern Area Planning Committee – 10 July 2014

Monxton Parish Council have had a number of complaints from residents over the last 18 months regarding the damming of the Pill Hill Brook using builders rubble and sandbags topped with turf by the previous resident, Simon Burgess, of Upper Mill House. Mr. Burgess dammed the river with the following effects:

1. Ensuring that there would be a plentiful supply of water going down the mill race past his property, ensuring water went down the mill race, even in summer. However, in the summer months, due to low water flows, this reduced dramatically the water down the original river route. The Environment Agency, for reasons never adequately explained to MPC or residents also re-designated the main river as the Mill Race with no justification. 2. This action ensured that the land along the river, which was a very boggy flood plain, dried out and made the river uninhabitable to aquatic life. In addition, Mr Burgess created an earth bridge (or another dam) with pipes through the middle further down the old river, which is the subject of a retrospective planning application by Lord Tanlaw currently with TVBC. 3. Note the flooding this has caused on the flood plain in the area surrounding the "illegal bridge", is actually evidenced by the photos in this application on your website, which were provided by the applicant's contractor, which prove the point exceptionally well.

Therefore MPC are delighted that the new owner, Lord Tanlaw, has put in this application to build a new weir. MPC, has however, already written to Lord Tanlaw last year and suggested the much cheaper route would have been to remove the rubble put into the river and sand bags by the previous owner at a much lower cost and re-instate the old weir, which worked well for several hundred years.

However, as was discovered last year and now this year that due to high water levels from incessant rain (predicted to be more the norm in the future) any man made obstruction to the flow of the water can quickly cause the river to flood.

While the floodplain in Monxton can cope with some of the water when there are high flows, we need the floodplain east of the dam, or new weir, in the land within the Upper Mill House estate to take its share and NOT cause the water to back up into Monxton village and properties.

Note this is further exacerbated by the issues with the pumping station in Monxton, which cannot cope with the sewage when high ground water levels are present, as we have been subject to two months of tankering 'black water' away from the village 20 hours/day and now have a large pump putting sewage and ground water into the river above the dam sending this down both channels.

We would also wish to have the applicant have Flood Defence Consent, under the Water Resources Act 1991, for application and therefore the new weir should obtain this consent.

Test Valley Borough Council – Northern Area Planning Committee – 10 July 2014

6.3 Amport Parish Council; Objects to the application unless the weir crest is lowered.

6.4 13 x letters; Objections from Little Thatch, Willow Glen, Meadow Lodge, unknown, Saddlers Cottage, Monxton Manor, 27 Sunnybank, Millcroft, The Owls, Dingley Dell, raising;  Seen the damage the previous (now reduced dam) did in terms of flooding due to redirection of natural flow even before recent catastrophic weather. Increasing the height of the weir will in effect create the dam anew and increase those flooding problems;  Fear the original dam and proposed changes to weir are for mere cosmetic desires rather than anything beneficial to the nature of the brook and surrounding area;  Raising the water as is proposed by the drawings would leave the bridge at Willow Glen subject to flooding and causing back-up of the water flow further upstream. This should have been taken into account in the Flood Risk Assessment;  The existing part of the dam is artificially raising the water level and the proposed increase in height of the replacement weir will only exacerbate the situation. There is nothing in the plans which would suggest it will be any lower and wider than the present dam and flooding will, therefore, still inevitably occur. The design of the proposed weir is not optimal for flow control. Diagram B of the existing is inaccurate as it makes the dam look lower than the land either side, which is not the case. If it is raised by 100mms, it will put it back up to higher, than that of the dam before it was reduced. The proposed makes the land on both sides of the weir higher than the existing land and only takes in to account moderate water levels not during either low or high flows. The design and increased height of the proposed weir will continue to impede the flow of water in to the natural channel of the brook, and will prejudice the health and future of this stretch of the brook. Plans of the weir are showing water levels at 07/01/14 and 4/12/13, whereas they need to show them at the highest point of water flow. The highest point occurs during February, March and April and unless calculations are made during these months, it will present an unreliable picture of the implications of the weir construction and its effect on the Pillhill Brook and neighbouring properties;  A v-profile weir positioned on the riverbed, which was the recommendation of an expert would, under low flow conditions, allow a flow of water in to the natural river channel of the Pillhill Brook, but as the water levels increase, a larger volume is able to pass over it;  The Flood Risk Assessment is an altogether inadequate since it is only concerned with land owned by the project proposer and does not address the flooding caused to the properties in the vicinity upstream. Neither does it take into account the Monxton sewage pumping station which has been unable to cope with the volume of ground/floodwater since New Year's Day 2014. An appreciable volume of raw, diluted sewage is flowing into the Pill hill Brook from this and any risk assessment will need to address it.

Test Valley Borough Council – Northern Area Planning Committee – 10 July 2014

This must, therefore, be covered together with the risk of future events of this nature occurring and, how they are to be addressed by what is a blockage of the Pillhill Brook caused by the existing and proposed dam/weir;  Should the Applicant wish to put forward a serious proposal for further water to be channelled past his property, while at the same time eliminating a flooding risk to adjacent properties, then a comprehensive risk assessment will need to be produced involving those who are subject to the adverse impact of the proposal in order that a solution can be identified which meets the needs of all parties. This will need to address such as issues as the height of the proposed structure, clearly identified, which it is not at the moment, and its impact on the surrounding area. Issues such as a failure of the Monxton Pumping Station will also need to be taken into account;  Although the proposed weir would be a significant improvement on the pile of rubble currently blocking the Pillhill Brook, reference to this structure as the ‘existing weir’ is misleading. Prior to the construction of what amounted to a dam, a low weir sufficed to provide a fair balance of flow between the mill stream and what is not being referred to as the ‘overflow carrier’. A return to the status quo is all that is needed to meet the requirements of this application;  The Flood Risk Assessment provided with the application correctly identifies the original function of the weir as the regulation of the flow to the mill. The mill is no longer operational and there is no hydraulic or mechanical significance to the water level in the mill stream. Consider that the design of the weir as currently envisaged favours the mill stream unreasonably at the expense of the ‘overflow carrier’. This will result in further winter flooding and unnecessary drying out of the latter;  A reduction in height of weir of at least 100mm would be more appropriate. If the new weir is to be increased by 100mm in height it will be another dam. The design and depth of the proposed weir is insufficient to ensure a flow of water to the natural channel in low flow conditions. This was the cause of the of the dry river bed in the natural channel of the brook which led to consequent damage to the ecology of this part of the brook;  There has been substantial flooding in this area and this plan to divert the river is likely to cause more misery to the homes that have suffered already. The river should be dredged but not diverted;  It is stated that 'Cain Bio-Engineering will establish suitable benchmarks before construction and use the benchmarks to keep a photo record to show the new weir crest height in comparison to the existing height: It is not acceptable in a location such as that of the proposed weir with its inherent hazards and risks to establish benchmarks after the Planning Application is made, such as is being proposed. This is because it is necessary to avoid the possibility of the structure causing flooding and damage to nearby properties such as that already caused by the dam constructed of predominantly builders' rubble. The applicant must identify precisely how high the proposed structure will be, calculated from a point such as the river bed. It is noted that Cain Bio-Engineering have stated that that 'The reason we chose the notch height as a reference point is due to their being no underlying fixed level of the old weir before it was covered in concrete bagwork'.

Test Valley Borough Council – Northern Area Planning Committee – 10 July 2014

This is incorrect as the Pillhill Brook river bed is, and always has been, the base of the weir, the large blocks of stones which constituted the original weir are likely to be found beneath the builders' rubble, undisturbed, of the existing dam and should be discoverable with little difficulty. Any other reference point is likely to lead to significant inaccuracies with likely flooding implications for nearby properties;  Nothing in the surrounding area has changed over the last thirty three years, such as water extraction or ground seepage/drainage. While these may have been referred to by the Applicant's agents, they are not material to this case and have no bearing on this Planning Application;  Upper Mill House has recently applied to have its culvert pipe access bridge retrospectively approved. It would seem prudent to wait first for a decision to be reached in relation to the culvert pipe bridge application. Otherwise, we risk making assessments in relation to the proposed weir which may no longer be relevant if the culver pipe bridge downstream from it is removed (Case Officer note: The application relating to the bridge, reference 13/01556/FULLN, has now been determined and planning permission granted);  The ‘explanatory note’ document prepared by Cain Bio-Engineering includes a photograph which shows clearly that the ‘large blocks of stone’ that constituted the weir at that time provided a fair balance of flow between the two channels;  This application contradicts the planning application 07/01498/FULLN, which included a map which clearly shows the mill race and main river channel. Reference to this section of the Pillhill Brook as an, "overflow carrier" is incorrect: this section of the Pillhill Brook is the natural main river channel;  It is stated on the application that the proposal will not increase the flood risk elsewhere, but damming the natural channel of the brook completely isolated it from its former floodplain. The natural channel was, in the past, an essential element in flood control;  No Flood Defence Consent, under the Water Resources Act 1991, has been provided to alter or raise the weir. The EA first inspected the dam due to receiving a complaint of, "concerns due to the weir being blocked." So why is there no comment from them?  The EA Flood Defence staff investigated the flooding last year and asked Mr Burgess to partially reduce the height of the dam to allow some water to flow in to the natural channel. They confirmed that prior to last year; the wettest winter was in 2000 and no flooding occurred then, or for decades prior to this, when the old weir was in place. There has been no consultation with other stakeholders, including neighbouring property and land owners. There has already been a detrimental effect on the flood risk to the surrounding area and will continue to do so in the future, if the weir is allowed to be raised again;  The proposed weir contravenes Riparian Law, which states that one of the Landowner's responsibilities is, "allowing the flow of water to pass without obstruction." If the height of the weir is raised, it will obstruct the flow of water in to the natural channel of the river;

Test Valley Borough Council – Northern Area Planning Committee – 10 July 2014

 A detailed Environmental Impact Assessment has not been provided. It is stated that "There are no existing protected species in the weir or the adjacent riverbank as the habitat is not suitable." But to the contrary, the agent, Mr Jeremy North reported in November 2013, that on this stretch of the brook, "Trout, kingfishers, and water vole are regularly seen and an excellent habitat for grass snakes has been provided." Surely it has to be one or the other? It also states that, "The existing weir is notched to allow a small flow through into the overflow channel. Inspection of the site on 4 December found that this small flow caused the overflow channel to run for approx. 50m before running dry. This phenomenon is typical where local ground water levels have been lowered by abstraction." There is no evidence that water abstraction has had an impact on this section of the Pillhill Brook in the past 30 years. The reason the natural channel ran dry was due to the unauthorised dam which had obstructed the flow of water in to the natural channel;  The application states that this proposal will be unlikely to have an impact on the water course, flower rich meadows/grassland and water meadows, despite the fact that due to the damming of the old weir, the natural main river channel ran dry and the river changed course, flooding the neighbouring water meadows for over three months. Expert opinion states that, "It is usual to favour the 'natural' channel rather that the artificial high level carrier (the Mill Race) on ecological grounds." The proposed weir will have an adverse impact on the ecological function and habitats of Pillhill Brook. The proposed raising of the height of the weir will cause increased depth of water upstream, which may drown fish spawning areas and have a negative effect on fish passage;  This weir is not in keeping with the Monxton Village Design Statement as it will contribute to a loss of habitat for these species including the brown trout, duck, moorhen and coot nest;  The proposed weir is not in keeping with the Abbotts Ann Village Design Statement as it will contribute to a loss of habitat for species including the skylark, Brown hare, water vole, red hemp nettle and wild brown trout;  This weir contravenes the requirements of the Test Valley Local Plan and it will not conserve or enhance biodiversity in the unique character of the Pill hill Brook, quite the opposite;  The proposed weir will affect the ecological function and habitats of Pill hill Brook and have adverse consequences for wildlife, including the water vole, whose habitat is protected under the CROW Act 2001 (not in accordance with the Habitats Regulations);  The Test Valley Local Biodiversity Action Plan (BAP) states that, " .. no development should be permitted that will result in the loss, deterioration or loss of habitat for a variety of rare and declining species' or species of importance to biodiversity or of importance for geological conservation, either directly or indirectly, will not be permitted" and that, "The habitats and species of importance to biodiversity and sites of geological interest considered in relation to points a) to c) comprise: priority habitats and species listed in the national and local Biodiversity." As such this weir should not be permitted;

Test Valley Borough Council – Northern Area Planning Committee – 10 July 2014

 This stretch of the Pill hill Brook is not a winterbourne, but as a consequence of the dam and the bridge further downstream, the riverbed ran completely dry, with a devastating loss of biodiversity (not in accordance with the Hampshire Biodiversity Action Plan);  This weir will have an adverse effect on the wild brown trout, which are a priority species in the UK Biodiversity Action Plan (BAP), as well as, an important stretch of unique (not in accordance with the UK Biodiversity Action Plan);  This application does not take in to account the history associated with the unauthorised damming of the brook by the previous owner. Due to this, a number of residents, many of whom have lived in Monxton for over thirty years, were adversely affected by unprecedented flooding. It is stated that there is not enough flow in the river to furnish both the mill race and the natural main river channel, but for decades prior to the unauthorised erection of the dam, both channels had substantial flow all year round, except in exceptional drought conditions;  The building of two unauthorised structures, that of the culvert bridge and the dam, on this stretch of the natural channel of the Pillhill Brook has had the consequence of isolating the brook from its former floodplain;  Immediate impact on the character of the area that was once a lush piece of countryside but now looks like a flood plain;  The character of the Pillhill Brook should be a free flowing strip of water which has now flooded due to a series of obstructions to which the weir will become another fault line;  The application goes against the Monxton Village Design Statement that identifies the free flowing Pillhill Brook as one of the major features of the village. Currently it is being blocked by a weir and by a bridge that is built in the path of, and provides a barrier to, what was a free flowing waterway;  The shape and design of the weir will mean a dry river bed in low flow periods and particularly concerned at the effect on Kingfishers (et al) that live along sections of the river bank;  The Wetlands within the BAP are breached in virtually all respects; 6.5 2 x letter; Comments from Monxton Mill, raising;  The planning application seeks to replace rather than reinstate the pre-2007 weir. The report within this application suggests what appears to be a sympathetic (but expensive) construction but lacks even handedness in its evaluation of risks;  Although the property immediately downstream has been taken into account it would have been more even handed and balanced to have included an assessment of the potential risks to neighbours and those upstream of Upper Mill House as the proposed weir is partially a dam;  The use of the term “existing level” is incorrect as it is really the “unauthorised level” as it emanates from the “unauthorised work” carried out. This planning application should really be assessing the changes to the pre 2007 situation and not from the current “unauthorised” work;

Test Valley Borough Council – Northern Area Planning Committee – 10 July 2014

 The diagrams seem to be “desktop” rather than observational: eg the brook is demonstrably wider as it passes under the bridge on the Andover Road, whereas the diagrams show it to be narrower (this is important as the Mill Race and proposed weir can act as a “choke” on the brook, which only comes to light during times of high water when its capacity to handle these flows is brought into question);  The proposed weir appears to be narrower than that existing pre 2007 and contains an element of damming as the base to the weir is proposed to be 100mm above the unauthorised level, yet no rationale is provided for this;  The proposed weir is a step in the right direction but does not take us back to the pre 2007 situation and the proposal does not provide compelling reasons why a replacement weir is required, rather than merely reverting to the original status;  Agree with the views of the Test and Itchen Association provided in their letter of April 7.

6.6 3 x letter; Comments from The Test and Itchen Association Ltd, raising;

We have visited this site on several occasions. We have held discussions with the proponent and his technical advisors, as well as with neighbours (both upstream and downstream), and parish councillors who are concerned about the risk of flooding and the ecological health of the Pillhill Brook. We have raised our concerns with the Environment Agency about the previous unconsented raising of the height of the existing weir structure and have discussed ways of addressing them, with both the EA and the County Council;

Our principal focus has been:  To ensure optimum access for fish migration: both upstream and downstream, to protect a native population of wild brown trout and other species  To prevent loss or deterioration of riverine habitat which is an explicit requirement of the Water Framework Directive  And to minimise unnatural flooding of upstream and adjacent land.

We have recommended the lowering and widening of the weir crest and construction of a weir profile which maintains a relatively constant flow down the mill leat: allowing proportionately more water down the by-pass (natural) channel during high flows, but proportionately less during low flows, whilst providing a sufficient flow to protect the ecology of the natural channel. This would in essence have been how the system would have been engineered when the mill was first built. We suggested that a weir crest with a wide open v- profile would achieve this. The efficacy of this approach has been amply demonstrated in the recent high flows, following removal of material to widen the weir. Despite the highest flows in living memory, the water level at the footbridge just upstream of the weir on 3 March was significantly lower (c10- 20cm) than it was on the 22 May 2013.

Test Valley Borough Council – Northern Area Planning Committee – 10 July 2014

We have examined the proposals in this application in detail and we are satisfied that they provide the right sort of weir profile both laterally and longitudinally, to address our concerns, while maintaining a constant flow the mill leat. However the lowest point of the proposed weir crest needs to be lower than the position indicated, in order to provide the necessary sweetening flow to the by-pass (natural) channel during lower water periods. Exactly what that height7 should be is probably best defined as the height of the original weir structure before any raising was carried out. Furthermore we favour the use of a soft engineering approach, rather than concrete and steel, since this provides scope for minor adjustment should the low-point be subsequently found not to be low enough.

We therefore support the application (14/00300/FULLN), on condition that the low-point of the weir crest is lowered as outlined above.

We have examined the additional documents on the web file, which confirmed our previous understanding of the proposals. The sections AA and BB (proposed) do not indicate the height of the lowest point of the proposed weir crest, and we agree with Jeremy North that this may have been ambiguous. What they do indicate, however, is that the lowest point would be higher than the base of the notch as shown on sections AA and BB (existing). Furthermore the lowest point of the proposed structure is higher than the water level as it was on 4 December 2013, suggesting that no water would pass over the weir crest and down the bypass (natural) channel at an equivalent water height.

We remain of the view that the low point of the weir crest needs to be lower than this in order to provide the necessary flow to protect the ecology of the by-pass (natural) channel, whilst there is ample scope for keeping a good flow down the mill stream. We accept that under extreme low flow conditions it may be necessary to favour one channel over the other in order to maintain fish passage, but we would expect such conditions to be rather more extreme that those on December 4 last year (flows at that time were roughly equivalent to the long term average). The great benefit of a soft engineering approach using gravel rather than concrete and steel, as proposed, is that there is scope for adjustment.

We continue to support the application, subject to lowering of the lowest point of the weir crest. We therefore recommend: a) That the low point of the new weir crest be defined from an established benchmark. According to section BB this would probably best be from the base of the bagwork, which is of the order 16cm lower than the lowest point of the weir crest as proposed. b) An overarching condition be included to manage the apportionment of flow between the two channels to protect the overall ecology of the river.

7.0 POLICY 7.1 Government Guidance National Planning Policy Framework (NPPF)

Test Valley Borough Council – Northern Area Planning Committee – 10 July 2014

7.2 Test Valley Borough Local Plan (2006)(TVBLP) SET03 - Development in the countryside ENV01 – Biodiversity and geological conservation ENV05 – Protected species ENV17 – Setting of Conservation Areas HAZ02 - Flooding DES01 – Landscape character DES06 – Scale, height and massing DES07 – Appearance, details and materials

7.3 Draft Revised Local Plan (2014) On the 8 January 2014 the Council approved the Revised Local Plan (Regulation 19) for public consultation. The statutory 6 week period of public consultation was undertaken from 24 January to 7 March 2014. The Council is currently in the process of acknowledging and analysing all the representations that were received. At present the document, and its content, represents a direction of travel for the Council. The weight afforded to it at this stage would need to be considered against the test included in para 216 of NPPF. It is not considered that the draft Plan would have any significant bearing on the determination of this application.

7.4 Supplementary Planning Documents (SPD) Village Design Statements;  Abbotts Ann

8.0 PLANNING CONSIDERATIONS 8.1 The main planning considerations are:  The principle of development  Impact on the character and appearance of the area and the setting of the adjacent Conservation Area  Impact on flooding  Impact on ecology

8.2 The principle of development The application site is located within the countryside for planning policy purposes. Policy SET03 of the Test Valley Borough Local Plan 2006 restricts development in the countryside unless there is an overriding need for it to be located there, or if it is of a type appropriate in the countryside as set out by other Local Plan policies.

8.3 The application advises that the provision of a weir is to ensure that there is a flow of water from the western end to the eastern end of the Upper Mill House property. There is not enough flow in the Pillhill Brook to service both the Mill Race and old water course together. There is also not enough volume of water during the summer and early winter periods to preserve a flow in the old river course alone, owing to depleted ground water conditions. The river bed dries up, as it is much wider and the ground in the bed becomes porous.

Test Valley Borough Council – Northern Area Planning Committee – 10 July 2014

Even with a reasonable flow over the weir in December the water sank into the ground after flowing approximately 200m, leaving the main straight section of the river completely dry. It has been agreed to keep the primary flow in the Mill Race with an improved structure which will enable more water to overspill the weir in times of flood than at present.

8.4 In view of the above, it is considered that it has been demonstrated that there is a reasonable requirement for the development in this countryside location, and the development complies with policy SET03 of the TVBLP.

8.5 Impact on the character and appearance of the surrounding area and the setting of the adjacent Conservation Area The proposed replacement weir would not project above the adjacent river banks, and together with its overall size and scale, would not be a prominent feature within the landscape. In any event, the proposed replacement weir would not be seen in public views from the surrounding area due to its isolated position relative to public vantage points. It is considered that the materials to be used in the construction of the proposed replacement weir would be appropriate for a construction of this nature, and as discussed above, would not be seen in public views. In view of the lack of public vantage points of the watercourse affected by the proposed development, it is also considered that the variations in water levels as a result of the proposed development would have a limited impact on the surrounding landscape. It is not considered that the proposed development would have an adverse impact on the character and appearance of the surrounding area. The proposal would also preserve the setting of the adjacent Conservation Area.

8.6 Impact on flooding The original weir that existed in this location has been modified in recent years, without the benefit of planning permission, with materials that have had the effect of reducing the amount of water that flows over the weir and into the overflow carrier (Pillhill Brook). The planning application proposes to rectify this situation by constructing a replacement weir which would allow more water into the overflow carrier than the existing situation at times of higher water flow through the mill leat. The planning application is supported by a Flood Risk Assessment, which concludes that although the proposed replacement weir would have a sill that would be installed approximately 100mm above the height of the existing weir, it would have a wider curved crest which would ensure that in low flows, the water through the mill leat is maintained at similar to existing levels, and in times of flood, more water is diverted through the overflow carrier than existing. The proposed development would be located within flood zone 3b (functional flood plain), however the Technical Guidance to the National Planning Policy Framework (Table 2: Flood risk vulnerability classification and Table 3: Flood risk vulnerability and flood zone ‘compatibility’) does not advise that this type of development is incompatible with this flood zone. Hampshire County Council, as the Lead Local Flood Authority, has raised no objections to the proposed development, and additionally, it is noted that Flood Defence Consent has now been granted by the Environment Agency for the proposed development (26 March 2014). Test Valley Borough Council – Northern Area Planning Committee – 10 July 2014

It is considered that the proposed replacement weir would function in such a way that would enable water at high flows to enter the overflow carrier, and this would not increase the risk of flooding elsewhere, including upstream, and the proposed development is acceptable in this respect.

8.7 Impact on ecology The Hampshire County Council Ecologist has been consulted on this planning application and has advised that the proposed weir will not affect any statutory or non-statutory site for nature conservation, nor is it likely to affect any legally protected or notable species. It is considered that suitable habitats would continue to be available in the vicinity for species known to be present at this site at times when the overflow carrier has no water running through it, which would occur due to the function of the proposed development. In addition, by enabling the overflow carrier to take water, this is likely to increase the diversity of habitats present over that which is present at the moment and may thus result in a net gain to biodiversity. It is not considered that the proposed development would have an adverse impact on biodiversity, and it is acceptable in this respect.

8.8 Other matters It is noted that as a riparian landowner, the applicant has a duty to ensure any structures on their land are properly maintained so as to allow the flow of water to pass without obstruction.

9.0 CONCLUSION 9.1 The proposed development is considered to be acceptable because it would not impact adversely on the character and appearance of the surrounding area, flooding or ecology, and in these respects complies with the relevant policies of the Test Valley Borough Local Plan 2006.

10.0 RECOMMENDATION PERMISSION subject to: 1. The development hereby permitted shall be begun within three years from the date of this permission. Reason: To comply with the provision of Section 91 of the Town and Country Planning Act 1990 as amended by Section 51 of the Planning and Compulsory Purchase Act 2004. Notes to applicant: 1. The development hereby permitted shall be carried out and completed strictly in accordance with the submitted plans, specifications and written particulars for which permission is hereby granted or which are subsequently submitted to, and approved in writing by, the Local Planning Authority and in compliance with any conditions imposed by the Local Planning Authority.

Test Valley Borough Council – Northern Area Planning Committee – 10 July 2014

2. In reaching this decision Test Valley Borough Council (TVBC) has had regard to paragraphs 186 and 187 of the National Planning Policy Framework and takes a positive and proactive approach to development proposals focused on solutions. TVBC work with applicants and their agents in a positive and proactive manner offering a pre-application advice service and updating applicants/agents of issues that may arise in dealing with the application and where possible suggesting solutions.