Schemes for Discharge of Conditions

Application Number: 4/V/2013/0028 Date of Application: 2/1/13 Site Address: Annesley Road to Station Road, Hucknall Condition(s) to be Discharged: 24 Text of Condition(s): No development shall commence on the construction of the road before detailed plans of the development hereby permitted have been submitted to, and approved in writing by, the CPA in consultation with the Environment Agency which incorporate the mitigation measures listed in the Detailed Assessment section of the Hucknall TCIS Water Framework Directive Assessment dated July 2013 and the plans contained within Appendix A2. . Schedule of Attachments: email - Hucknall WfD Addendum Hucknall WfD addendum - PDF H-JH13379-112D.pdf H-JH13379-114C.pdf

Fee Paid: £97.00 Note: Condition number(s) must be specified in the journal

Applicant Contact Name: Tom Boylan Tel No.: 9774227

Applications to be submitted by email to: [email protected]

For Planning Use Only

Date of Receipt Target date:

Sent Rec’d Sent Rec’d Sent Rec’d Highways Coal Authority HSE Countryside Access EA Sport England Ecology Severn Trent Ramblers Planning Policy Gas English Heritage Forestry/Arb Electric Highways Agency Landscape Anglian Water (Bassetlaw) Forestry Commission Waste/Energy Mgt Natural England Airfield Noise –Clayton NWT British Horse Society Crime Disorder Canal & River Trust Internal Drainage Board Land Reclamation Network Rail Sara Williams - CFCS Road Safety National Grid Conservation/Arch National Planning Conservation L/B Casework Unit

Notes

1 SchemesForDischargeOfConditions_v1

Hucknall TCIS WFD Addendum

Water Framework Directive Assessment

May 2015

47070861

Prepared for: Nottinghamshire County Council

UNITED KINGDOM & IRELAND

Hucknall Town Centre Improvement Scheme

Water Framework Directive Assessment Addendum

REVISION SCHEDULE

Rev Date Details Prepared by Reviewed by Approved by

Lucy Rushmer Michael Brierley Senior Consultant Andrew Woodliffe 1 May 2015 Addendum Draft Graduate Consultant Neil Williams Associate Director Principal Consultant

URS Infrastructure & Environment UK Limited Royal Court, Basil Close, Chesterfield, Derbyshire, S41 7SL

Tel: 01246 209 221 Fax: 01246 209 229 www.ursglobal.com

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Limitations

URS Infrastructure & Environment UK Limited (“URS”) has prepared this Report for the sole use of Nottinghamshire County Council (“Client”) in accordance with the Agreement under which our services were performed. No other warranty, expressed or implied, is made as to the professional advice included in this Report or any other services provided by URS. This Report is confidential and may not be disclosed by the Client nor relied upon by any other party without the prior and express written agreement of URS. The conclusions and recommendations contained in this Report are based upon information provided by others and upon the assumption that all relevant information has been provided by those parties from whom it has been requested and that such information is accurate. Information obtained by URS has not been independently verified by URS, unless otherwise stated in the Report. The methodology adopted and the sources of information used by URS in providing its services are outlined in this Report. The work described in this Report was undertaken between March 2015 and May 2015 and is based on the conditions encountered and the information available during the said period of time. The scope of this Report and the services are accordingly factually limited by these circumstances. Where assessments of works or costs identified in this Report are made, such assessments are based upon the information available at the time and where appropriate are subject to further investigations or information which may become available. URS disclaim any undertaking or obligation to advise any person of any change in any matter affecting the Report, which may come or be brought to URS’ attention after the date of the Report. Certain statements made in the Report that are not historical facts may constitute estimates, projections or other forward- looking statements and even though they are based on reasonable assumptions as of the date of the Report, such forward-looking statements by their nature involve risks and uncertainties that could cause actual results to differ materially from the results predicted. URS specifically does not guarantee or warrant any estimate or projections contained in this Report. Copyright © This Report is the copyright of URS Infrastructure & Environment UK Limited. Any unauthorised reproduction or usage by any person other than the addressee is strictly prohibited.

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TABLE OF CONTENTS 1 INTRODUCTION ...... 1 1.1 Background ...... 1 1.2 WFD Status ...... 1 1.3 WFD Update ...... 1 2 WFD PRELIMINARY ASSESSMENT UPDATE ...... 3 2.1 Geomorphological Assessment ...... 3 2.2 EMEC Ecological Survey ...... 3 3 WFD FURTHER ASSESSMENT UPDATE ...... 4 3.1 Options Appraisal ...... 4 3.2 Impacts and Potential Mitigation Measure Options ..... 4 3.3 Impact and Mitigation Extents ...... 4 3.4 Impacts and Potential Mitigation Measure Options within the HTCIS Boundary ...... 4 3.5 Impacts and Potential Mitigation Measure Options Outside the HTCIS Boundary ...... 6 3.6 Summary ...... 8 4 POST PROJECT APPRAISAL ...... 10 5 CONCLUSIONS ...... 11 APPENDIX A...... A APPENDIX B...... B APPENDIX C...... C APPENDIX D...... D

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1 INTRODUCTION

The proposed development of the Hucknall Town Centre Improvement Scheme (HTCIS) forms part of a strategy for positive action to prevent the economic decline of Hucknall town centre. A detailed description of the scheme is given in the Supporting Planning Statement1.

To enable the HTCIS to progress, proposals to extend an existing culvert on Albert Street Rec Street Brook at Station Road and the construction of a new culvert on Baker Brook (see Appendix A) required a Water Framework Directive Assessment (WFDa). A WFDa was undertaken in June 2013, which highlighted the detrimental impacts of the culverts to WFD objectives, and proposed mitigation measures that would result in an overall improvement to the waterbody2. A key component of these measures was the use of combined flood storage – aquatic habitat areas within the HTCIS.

Since the previous WFDa, and in consultation with the Environment Agency (EA), Nottinghamshire County Council (NCC) has decided to remove the flood storage areas due to maintenance concerns. Alternative water environment mitigation measures are therefore required for the updated scheme design.

The intention of this draft WFDa Addendum is to recommend alternative mitigation measures that should sufficiently compensate the deteriorating impacts of the HTCIS on the waterbody status (primarily the unavoidable need for culverting). This draft issue is intended for the scheme designers to select which of the recommended options they would like to incorporate into the HTCIS. Only those selected options will be included in a Final WFDa Addendum for inclusion in the forthcoming planning proposals.

1.1 Background

The original WFDa for the HTCIS was undertaken in June 2013, to assess the impacts of culverts on the local water environment, review the scheme’s compliance with Water Framework Directive (WFD) objectives, and implement mitigation measures including recommendations to alter the scheme design.

A detailed description of scheme baseline and impacts, and the mitigation approach discussed with the EA, are included in the 2013 report. Only necessary updates are included in this Addendum.

1.2 WFD Status

The River Leen (from Source to Day Brook) waterbody status has not changed since the completion of the original WFDa. For the comprehensive description of the HTCIS impacts on the waterbody please refer the original WFDa. Current waterbody status can be seen in Table 1-1 of this Addendum for convenience.

1.3 WFD Update

The WFD is now into its second cycle (2015-2021), however the new River Basin Management Plans (RBMP) are still in the consultation phase and are not projected to be released until after this WFDa Addendum has been finalised. It is not anticipated that the River Leen (from Source to Day Brook GB104028052880) will experience a deviation from its Moderate status as stated in the 2009 Humber RBMP.

1 Nottinghamshire County Council (2012). Hucknall Town Centre Improvement Scheme Supporting Planning Statement. 2 HTCIS (2013), Water Framework Directive Assessment DRAFT May 2015 1

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Table 1-1 – Surface Waterbody Status Classification Details

Status

Invertebrates

HumberRiv Basin Management Plan Waterbody Name/ID Current Ecological Status Ecological Objective Hydro morphologica l Status Current Chemical Status Fish

Good River Leen Ecological 2009 (from source Potential Humber to Day Brook) Moderate a by 2027; HMWB a Good b Good e Moderate RBMP GB104028052 Good 880) a Chemical by 2015

WFD River Leen surface (from source water Good by to Day Brook) Moderate HMWB Good High Moderate status 2027 GB104028052 objectives f 880) 2012

a As listed in the Humber RBMP 2009 b According to 11 sample points recorded by the EA in 2012 c Two elements (pH and ammonia) scored moderate and 14 others scored high by the EA in 2012 d Two sample sites scored moderate, plus one scored good and one scored high by the EA in 2012 e According to one sample site scored by the EA in 2012 f. Water Framework Directive – Surface Water Classification Status and Objectives 2012

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2 WFD PRELIMINARY ASSESSMENT UPDATE

2.1 Geomorphological Assessment

An additional site visit was completed on 23rd March 2015 to identify if there were any significant changes to the Baker Lane Brook or Albert Street Rec Brook within the HTCIS. Additionally, areas upstream were surveyed to assess their feasibility for providing compensation for the HTCIS culverts. Site observations and desk study conditions have not changed significantly from the original assessment, which showed that the channel through Hucknall is heavily impacted by urban encroachment, loss of riparian zones and channel straightening.

The channels through Hucknall town centre have historically been realigned and straightened and are either extensively culverted or otherwise wholly impounded, such that channel form is more-or-less uniform. The channel bed is dominated by sand with some gravels, and there appears to be a tendency towards bed scour, possibly as a result of historic channel straightening, and therefore a loss of pre-impact substrate habitats. The riparian zones have been lost to development, which has also resulted in the replacement of natural channel banks with hard engineering.

2.2 EMEC Ecological Survey

EMEC Ecology will conduct a second Ecological Survey in the summer of 2015 (date still not confirmed) to determine whether the watercourse has experienced significant change since it was previously surveyed in 20093. The 2009 survey indicated that Baker Lane Brook was relatively clear and flowing freely (at the survey site). The survey found that refugia were fairly limited (matching the waterbodies invertebrate status of moderate).

3 EMEC Ecology (2012). Proposed Improvement of Hucknall Town Centre, Nottinghamshire: Ecological Impact Assessment. DRAFT May 2015 3

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3 WFD FURTHER ASSESSMENT UPDATE

3.1 Options Appraisal

Some mitigation measures proposed in the original WFDa have now been removed from consideration due to alteration of the scheme design. Others are retained and, and some new measures are introduced in this Addendum.

It is known that de-culverting and river habitat improvements are already planned within separate developments throughout the River Leen (from source to Day Brook) waterbody. For example, the Darlison Court development upstream of HTCIS appears to be in progress and appears to be in the vicinity of the River Leen waterbody. However, separate developments are reliant on separate landowners and it is not practical to enter partnership agreements to assure these improvements through the HTCIS. NCC remains keen, however, to work with these third parties in pursuit of WFD objectives through their county-wide role and lessons learned from the HTCIS.

3.2 Impacts and Potential Mitigation Measure Options

In order to mitigate the impacts of unavoidable culverting, potential mitigation measure options have been assessed to improve the conditions of the watercourse throughout the HTCIS area and the rest of the River Leen (from source to Day Brook) waterbody.

The purpose of this draft WFDa Addendum is used to recommend mitigation measures for the scheme designers to select, and only those selected options will be included in a Final WFDa Addendum for inclusion in the planning proposals.

In order to maintain flood capacity of Baker Brook flowing through the HTCIS and the greater Hucknall area, in-channel mitigation measures need to be implemented in moderation. Some measures can be implemented within the HTCIS that would not affect flood risk, but the majority of measures will need to be located within the same waterbody but outside the scheme boundary.

3.3 Impact and Mitigation Extents

For convenience, the watercourse through the HTCIS has been divided into reaches, which represent WFD impact or mitigation units. The seven reaches are shown in Appendix A.

The proposed culvert at Albert Street parking area (in Reach 4) and the culvert extension at the junction of Station Road and Ashgate Road (Reach 7) remain largely unchanged from the original WFDa. These culverts remain integral to HTCIS and will require EA approved mitigation measures to compensate for the loss of existing open watercourses. Proposed mitigation measures are summarised below.

3.4 Impacts and Potential Mitigation Measure Options within the HTCIS Boundary

The HTCIS would create valuable green space and community areas centred around Baker Lane Brook. Daylighting 28m of existing culvert within Reach 2 at Titchfield Street will be a significant improvement. However, benefits will be limited because habitats will remain heavily constrained by grey bank protection, an over-wide river channel and limited bed and flow diversity.

Options are therefore proposed below for Reaches 1, 2 and 4, which would offer the opportunity to improve bed and flow diversity, for example to create improved habitat for both white-clawed crayfish and fish (Bullhead and Brown Trout).

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Option A – Improve In-Channel Hydromorphology and Riparian Habitat within HTCIS Boundary

Combined use of stone riffles and pre-vegetated fibre rolls would promote flow diversity in the form of pools and riffles and a sinuous baseflow planform with marginal habitats in the channel. An annotated design sketch of baseflow improvements within Reach 4 is presented in Appendix B. Whilst this focuses on the Albert Street area, these proposals are also appropriate for Reaches 1, 2, and 4. This would improve in-channel (including marginal) habitats.

Morphological processes and flow variability are important and are often used as indicators of recovery for rivers across the UK. The installation of stone riffles would create flow variability by creating areas of relatively fast flow, with slower flowing water and different habitats within pools and at the margins where water is deeper. Stone riffles should trigger local habitat variance around baseflow conditions but should not impact the current flood capacity of Baker Lane Brook, as they will be ‘drowned out’ during flood events.

An example of successful stone riffle design can be found within the River Restoration Centre (RRC) Manual of River Restoration Techniques4.

Additional riparian habitats could be improved but due to space constraints, these riparian options are only feasible in Reach 2. In this area, staked colonised vegetated fibre rolls could create small and local riparian habitat along the banks, providing shelter for fish and crayfish during high flows. Pre colonised vegetated fibre rolls will increase the likelihood that healthy and stable riparian habitat is maintained through the lifespan of the scheme. This would also help to establish desired plant species, control the risk of colonisation by invasive species, and reduce the need for vegetation maintenance by targeting low maintenance species.

Option B – Improve Physico-Chemical and Hydromorphological Elements Through Sustainable Urban Drainage Systems (SuDS)

The Baker Lane Brook is over-wide and appears to have problems with excess deposition of sand and fine grained sediments. Sediments derived from urban land use are often contaminated, and can have a significant impact on water quality as well as physical bed structure.

The use of hydrodynamic separators or SuDS located within outfalls can significantly decrease the amount of urban sediment and pollutants entering the watercourse, as well as helping to manage surface water and combined fluvial flooding. This would benefit all reaches. However, sediment controls may require a maintenance plan to remove deposited sediment from within the structure.

Option C - Improve Longitudinal Connectivity of Baker Lane Brook.

It is recommended that the base of the box culvert at Albert Street car park in Reach 2 is set below bed level if this is feasible within existing designs. This would allow for the continuation of a gravel bed from upstream, through the culvert, to the downstream reach. This would help maintain river continuity in terms of physical substrate transport processes and the passage of aquatic species through the culvert.

The proposed daylighting of the short section of the Baker Lane Brook (approximately 28m in length and 1.7m wide) will create a new open watercourse to reintroduce natural channel processes, but at 1.7m wide would be unnaturally wide and this could compromise habitat conditions. A two-stage channel could be designed with a sinuous planform without increasing

4 RRC Manual of River Restoration Techniques, Stone Riffle. Last viewed April 2015 http://www.therrc.co.uk/MOT/Final_Versions_%28Secure%29/3.3_Skerne.pdf DRAFT May 2015 5

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flood risk or debris blockage potential. A two-stage channel would allow the channel to regain a more natural cross section form and would deepen baseflow within the proposed low-flow channel (see Appendix C).

In order to help manage flood risk it is proposed that the existing Titchfield culvert could remain ‘online’ to act as an overflow channel during high flow events to increase flood storage in this area.

Figure 1 Baker Brook looking Figure 2 Baker Brook looking upstream downstream from Baker Street from Titchfield Street

It should be noted the degree of waterbody improvements that can be achieved within the HTCIS boundary will be inherently limited due to urban nature of the area. It will be impossible to fully re-naturalise the channel, so benefits to the aquatic environment will inevitably be restricted.

In order to ensure that the HTCIS does not result in waterbody deterioration, it is therefore recommended that additional measures are implemented outside of the HTCIS boundary to secure obvious improvements at waterbody scale.

3.5 Impacts and Potential Mitigation Measure Options Outside the HTCIS Boundary

Due to flood risk concerns in the area of the HTCIS and the need to mitigate flood risk by designing the channels with a preference for drainage efficiency as well as habitat complexity, mitigation measures will need to be located outside the HTCIS but within the same River Leen (from source to Day Brook) waterbody.

Several mitigation areas have examined including Dob Park, the park land boarded by Linby Walk and Wighay Road, and Butler’s Hill downstream of the proposed Station Road culvert extension between Wigham Lane and the railway line. High level review of the practicability of environmental improvements has identified Dob Park as the preferred area for WFD mitigation measures.

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Dob Park, which is under NCC ownership, is located north west of Hucknall town centre, and bordered by the A611 Hucknall Bypass to the east. A heavily modified, unnamed watercourse tributary to the River Leen from source to Day Brook (i.e. part of the same waterbody) flows through Dob Park in an easterly direction. It has been historically straightened, has re-profiled banks, and has a series of weirs with no apparent present day function (Figures 3 and 4). It therefore offers significant opportunities for improvement to the water environment that would mitigate the effects of the HTCIS.

Figure 3 (Left) Unnamed watercourse flowing through Dob Park Figure 4 (Above) Channel impounded by weir in Dob Park

Option A - Dob Park Flood Attenuation Wetland

The unnamed watercourse is culverted under the A611 Hucknall Bypass and confluences with Baker Lane Brook in the approximate vicinity of Greenwood Avenue. There is an overflow culvert that originates from what is believed to be Baker Lane Brook (not identified on Ordnance Survey maps) flowing towards the unnamed watercourse. This artificial confluence between the unnamed watercourse and the overflow culvert provides an opportunity to create a wetland area that would benefit flood attenuation and habitats.

The wetland would be located between the Dob Park entrance off the A611 and Washdyke Lane (Appendix D), and would be throttled by the existing infrastructure, thus providing a quick win opportunity. Wetlands are excellent WFD options for their benefits of water retention, water quality improvements, reducing delivery of fine sediment downstream within a wider valuable habitat.

Initial, high level review of ground elevations in the vicinity of the existing culvert and confluence suggest that 500m2 of wetland could easily be achieved with some simple excavations (see a rough indicative area in Appendix D). For the sake of comparing against lengths of new culverts for the HTCIS, wetlands could easily extend for 50-60m along the watercourse; equivalent to the length of new culverts minus deculverting (see Table 1). Further investigations are recommended in order to maximise and quantify the opportunity.

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Option B – Dob Park River Restoration

In combination with the wetland development or as a standalone option, it is suggested that a length of the straightened unnamed watercourse in Dob Park be restored to its natural sinuous planform. There are approximately 500m of straight watercourse that flows in open park land. The channel is showing signs of natural recovery from straightening, but it is unlikely that the watercourse can fully naturalise on its own (Figure 5).

Reinstating sinuosity would reinstate the pre-modified (straightened) river corridor and substantially improve the currently degraded morphological and ecological conditions. It would also help to reduce flow rates through the park towards the A611, which would provide flood management benefits.

A wetland and channel restoration scheme has great potential to create a positive amenity feature for Dob Park and the local community, by enhancing the water features and wildlife potential of the park for recreational benefits and providing educational facilities. The river restoration and wetland Figure 5 Formerly Straightened construction offers the potential to provide up to Watercourse in Dob Park approximately 500m of riparian improvements compared to the approximate 87m that are expected to be degraded as a result of the HTCIS.

3.6 Summary

The positive and negative effects of the HTCIS in WFD terms are compared for the different reaches in Table 1 (cf. Appendix A). This table has been updated from the original WFDa, and presents a tangible summary of the extents of the HTCIS culverts and newly recommended mitigation measures compared in terms of the extents of:

1. De-culverting. 2. Other new open watercourse. 3. In-channel mitigation measures. 4. Bank / riparian mitigation measures.

The River Leen (source to Day Brook) waterbody is 32km in length5. This means that in the context of the waterbody as a whole, a net increase of 87m of new culverts within a 32km long waterbody equates to a negative impact on less than 0.27% of the waterbody. There are opportunities throughout the waterbody to more than offset these impacts and to improve the overall WFD potential of the River Leen (source to Day Brook).

5 Water Framework Directive – Surface Water Classification Status and Objectives 2012. Last accessed April 2015 http://data.gov.uk/dataset/wfd-surface-water-classification-status-and-objectives. DRAFT May 2015 8

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TABLE 1: SUMMARY OF THE EXTENTS OF NEW CULVERTS, DE-CULVERTING AND OTHER

MITIGATION MEASURES

pen pen

igation igation

Channel Channel

Notes

(m)

Reach

Culvert (m) Culvert

Extent of De Extent

Extent of New of New Extent

Culverting (m) Culverting

Measures (m) Measures

Extent of Bank / / of Bank Extent

Watercourse (m) Watercourse

Riparian Mit Riparian

Extent of New of New Extent

Mitigation Measures Measures Mitigation Extent of In of Extent

Space allows for in-channel mitigation 1 - - - 74 - measures only

Space allows for in-channel and bank 2 - 28 - 28 28* mitigation measures *

3 - - - - - Outside HTCIS boundary.

Space for mitigation measures to both 4 19 - 23 58 - sides of the watercourse upstream of the culvert

5 - - - - - Outside HTCIS boundary.

6 - - - - - Outside HTCIS boundary.

No mitigation space available in HTCIS 7 67 - - - - boundary.

Cumulative Negative (+28) (+23) (+160) (+28)* * Only extents along the watercourse are Effects of impact included in the table, so as not to double- Mitigation count banks and riparian zones

(m) -86 -58 -35 +125 +153*

Notes

(m)

Reach

tent of In of tent

Culvert (m) Culvert

Extent of De Extent

Measures (m) Measures

Extent of New of New Extent of New Extent

Culverting (m) Culverting

Measures (m) Measures

pen Watercourse pen Watercourse

Extent of Bank / / of Bank Extent

Channel Mitigation Mitigation Channel Riparian Mitigation Mitigation Riparian

HTCIS Outcome of recommended measures -86 -58 -35 +125 +153 Mitigation within the HTCIS boundary. Dob Park 50-60 50-60 - - - Wetlands or more or more Additional mitigation within the same waterbody can be implemented upstream Dob Park Up to Up to of the HTCIS at Dob Park. Main - - - 500 or 500 or 2 Up to 500m or more of wetland (50-60m Channel more more along the channel ) and/or up to 500m or Effects of Up to Up to more of re-meandering could be Mitigation - - - 675 or 700 or achieved in the Park. (m) more more

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4 POST PROJECT APPRAISAL

A monitoring strategy should be developed at detailed design stage, to monitor the short and longer term impacts of the channel alterations.

Mitigation measures may include the introduction of in channel features within a confined urban river, the restoration of an unnamed watercourse and the creation of a wetland/flood alleviation area to promote the development of natural flow conditions and riparian habitats. These are intended to allow the river to create a more naturalised sediment regime. The placement of stone riffles onto the channel bed will promote morphological diversity and the deposition of substrates to form a self-regulating low-flow channel of more natural dimensions than exist at present.

These improvements would locally affect channel geometry, and although this will be restricted to the new open landscape areas, careful monitoring will be required to ensure that there is no increase in the risk of flooding (particularly at the culvert in Reaches 2 and 4) or scour at structures, and that local channel habitats begin to establish appropriately. The principle of the mitigation measures is that there would be minimal intervention to creating in- channel habitats, and that the river will be allowed to establish a self-regulating morphology. It should also be noted that no major channel changes are anticipated, so no significant flood or erosion risks are expected.

Post-project appraisal would be based on site visits by experienced personnel, and would be documented with photographs and brief notes on any relevant issues. Initially, site visits would take place seasonally twice a year for the first two years, and after at least two significant storm events. Post-scheme monitoring would be co-ordinated with flood risk specialists, ecologists and/or structural engineers. The need for future monitoring should be reviewed after two years.

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5 CONCLUSIONS

URS was commissioned by NCC to undertake a detailed Water Framework Directive Assessment (WFDa) as part of the HTCIS in June 2013. The scheme proposals assessed in that report have now been updated, requiring an update to the previous WFDa.

The implications of the scheme in WFD terms are summarised as follows:

 The HTCIS would affect a small part of River Leen (Source to Day Brook) waterbody, which is of Moderate Ecological Status. The scheme must not allow the existing status to deteriorate, or prevent any recommended future mitigation measures from being implemented.

 A second hydromorphological survey of the HTCIS area and additional areas outside of the scheme boundary established that the local river habitat is generally degraded from natural conditions due to historic realignment. However, Fish species (brown trout, bullhead) and white-clawed crayfish have been documented within the study area.

 The HTCIS requires a new culvert and a culvert extension, totalling approximately 86m. The HTCIS also includes the daylighting of approximately 28m of existing culvert, which reduces the impact of new culverts like-for-like. The impacts of the new culverts are further offset by the creation of approximately 23m of new open watercourse at the Albert Street parking area. The net impact on open watercourses, without mitigation measures is therefore a loss of approximately 35m. Additional mitigation measures are therefore required.

 Mitigation measures are proposed within the HTCIS boundary that would improve in- channel conditions and bank and riparian habitats, by helping to rehabilitate the channel. If all of the measures are implemented, it appears that they may be able to offset the deteriorating lengths of the proposed culverts. However, it should be noted the degree of waterbody improvements that can be achieved within the HTCIS boundary will be inherently limited due to urban nature of the area. It will be impossible to fully re-naturalise the channel, so benefits to the aquatic environment will inevitably be restricted.

 In order to ensure that the HTCIS does not result in waterbody deterioration, it is therefore recommended that additional measures are implemented outside of the HTCIS boundary to secure obvious improvements at waterbody scale.

 Mitigation measures suggested at Dob Park north west of the HTCIS have the potential to create up to 500m of improved watercourse if all options are included. The mitigation measures include creation of a wetland area and up to 500m of rehabilitation of formerly straightened channels.

 The mitigation options put forward are based on geomorphological principles with WFD objectives the primary focus and are suggestions based on the current scheme design and it is the responsibility of NCC and EA to determine which options are best suited for the HTCIS.

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APPENDIX A

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APPENDIX B

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Stone Riffles (Will require in depth geomorphological assessment to determine correct pool / riffle sequencing and related channel geometry associated with scheme.

Pools (Will require in depth geomorphological assessment to determine correct pool / riffle sequencing and related channel geometry associated with scheme.

Marginal Habitat – in the form of fibre plant rolls. Will require input from ecology to determine species to be pre planted. (Vegetated rolls are not always effective)

Existing bed Water Level

Pool

Stone riffle (weir) from densely graded rock (can be permanently secured to the bed if required). Depth (To be Feature would be submerged at low flow. determined based on Pools – pools located at either extent of culverts would site requirements) provide refuge for migrating fish. Culvert dimensions likely mean that fish passage or bed features cannot be placed within. Hucknall Town Centre Improvement Scheme

Water Framework Directive Assessment Addendum

APPENDIX C

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REPLACE TWIN CULVERT WITH

BOX CULVERT

WEIR TO STOP BASEFLOW, BUT ALLOW FLOOD FLOWS TO ENTER EXISTING CULVERT

FLOOD FLOWS

LOW FLOW CHANNEL. SINUOUS PLANFORM TO BE DETERMINED THROUGH EXTEND DE-CULVERTING OF GEOMORPHOLOGICAL THE BAKER BOOK PARALLEL ASSESSMENT TO TITCHFIELD ST.

CHANNEL TERRACE. ACTS AS FLOOD PLAIN AND RIPARIAN HABITAT

SECTION B-B

PLAN ON PROPOSED TITCHFIELD STREET OPEN WATERCOURSE Hucknall Town Centre Improvement Scheme

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APPENDIX D

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Existing Overflow Culvert

Seasonal & flood flow connection Reconnected Floodplain

Marginal wet zone Marginal wet zone

Deep pool

Lowered Reconnected Restore channel to natural Floodplain planform

Sorry for my late reply, Dan did pass it over to me as soon as you had sent the documents!

The report provided accurately describes the channel as “heavily impacted by urban encroachment” and the previous WFD assessment “highlighted the detrimental impacts of the culverts to WFD objectives, and proposed mitigation measures that would result in an overall improvement to the waterbody”. These proposed measures consisted of aquatic habitat areas which are described in this addendum in Option A. We would wish to see all of the options detailed in this report fulfilled in order to appropriately mitigate for the works, this includes the measures proposed outside of the boundary in Dob Park.

I am pleased with Option A and will be happy to advise further on any design, this might include; low level berms; two stage channels; woody dams or reflectors; refugia sites. This option provides easy wins and should be included as standard practice, but standing alone does not provide sufficient mitigation.

Option B is also pleasing and I would expect all new developments to include SUDS. There are further options within this to be explored alongside improvements to outfalls, such as Raingardens – which themselves can be attractive on the streets/pavements and can be an excellent interceptor of road/surface water run off. Such SUDS require a degree of ongoing maintenance, especially sediment controls as described, the degree of maintenance and a named responsible body must be provided within a management plan. Further SUDS should be considered, such as green roofs, swales, rain gardens, permeable paving, water retention ponds, water butts for residences, etc.

I am also very keen to pursue the Dob Park improvements proposed, such a stretch of channel will currently be contributing to sediment loading within the Leen and the straightened channel will not be helping to improve flood risk in its current form. Incorporating a river restoration scheme within this scheme (even on a smaller water body such as this unnamed channel) will be adding benefit to WFD targets, particularly in the main channel by helping to reduce siltation, slowing down flows and improving the water quality going into the main brook. We would prefer a bank of sorts to be designed between the main channel and the proposed wetland area, this is to prevent the area becoming a silt trap and being flushed through in periods of high flows, we would be happy to comment further on any specific designs later on.

Please let me know if I can provide any more details or any clarification on the above points,

Many thanks,

Katie Swindley Biodiversity Officer Trentside Offices, Scarrington Road, NG2 5BR