River Douglas Catchment Flood Management Plan Summary Report December 2009 Managing Flood Risk We Are the Environment Agency

River Douglas Catchment Flood Management Plan Summary Report December 2009 managing flood risk We are the Environment Agency. It’s our job to look after your environment and make it a better place – for you, and for future generations. Your environment is the air you breathe, the water you drink and the ground you walk on. Working with business, Government and society as a whole, we are making your environment cleaner and healthier. The Environment Agency. Out there, making your environment a better place.

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Environment Agency Richard Fairclough House Knutsford Road Warrington WA4 1HT Tel: 0870 8506506 Email: [email protected] www.environment-agency.gov.uk

I am pleased to introduce our summary of the River Douglas Catchment Flood Management Plan (CFMP). This CFMP gives an overview of the flood risk in the River Douglas catchment and sets out our preferred plan for sustainable flood risk management over the next 50 to 100 years.

The River Douglas CFMP is one of 77 CFMPs for England surge or from backing up of river water due to high and Wales. Through the CFMPs, we have assessed tides. Serious flooding has been recorded in Wigan, inland flood risk across all of England and Wales for Croston, Appley Bridge, Leyland and Whittle Le Woods. the first time. The CFMP considers all types of inland There are currently more than 2,200 properties at risk flooding, from rivers, groundwater, surface water of flooding in a 1% Annual Probability Event (APE) and tidal flooding, but not flooding directly from the (this includes some tidal flooding). An additional 329 sea (coastal flooding), which is covered by Shoreline properties across the CFMP area would be at risk of Management Plans (SMPs). Our coverage of surface flooding from rivers or the sea in a future 1% event. and groundwater is however limited due to a lack of We cannot reduce flood risk on our own, we will available information. therefore work closely with all our partners to improve The role of CFMPs is to establish flood risk management the co-ordination of flood risk activities and agree policies which will deliver sustainable flood risk the most effective way to management flood risk in management for the long term. This is essential if we the future. To develop this plan and ensure social, are to make the right investment decisions for the economic and environmental issues were taken future and to help prepare ourselves effectively for into account we worked with, and consulted many the impact of climate change. We will use CFMPs to organisations. These include United Utilities, South help us target our limited resources where the risks Ribble Borough Council, Lancashire County Council, are greatest. Chorley Borough Council Natural England, English Heritage, NFU and Defra. This CFMP identifies flood risk management policies to assist all key decision makers in the catchment. It was This is a summary of the main CFMP document, if you produced through a wide consultation and appraisal need to see the full document an electronic version process, however it is only the first step towards an can be obtained by emailing enquiries@environment- integrated approach to Flood Risk Management. As we agency.gov.uk or alternatively paper copies can be all work together to achieve our objectives, we must viewed at any of our offices in North West Region. monitor and listen to each others progress, discuss what has been achieved and consider where we may need to review parts of the CFMP.

Flooding in the Douglas CFMP area can be due to rivers overtopping their banks or from surface water, particularly in built up areas. There is also a risk of Tony Dean flooding from the sea, due to high tides and storm Regional Director

Environment Agency River Douglas Catchment Flood Management Plan 1 Contents

The purpose of a CFMP in managing flood risk 3

Catchment overview 4

Current and future flood risk 6

Future direction for flood risk management 10

Sub-areas 1 Wigan 12 2 Appley Bridge and Croston 14 3 Tidal River Douglas 16 4 Fluvial Yarrow 18 5 Leyland and Lostock to Whittle Le Woods 19 6 Horwich 20 7 Tidal Villages 22 8 Rivington 23 9 River Douglas 24 10 Rural Lostock and Yarrow Communities 26

Map of CFMP policies 28

2 Environment Agency River Douglas Catchment Flood Management Plan The purpose of a CFMP in managing flood risk

CFMPs help us to understand the • Internal Drainage Board, water CFMPs aim to promote more scale and extent of flooding now companies and other utilities to sustainable approaches to managing and in the future, and set policies help plan their activities in the flood risk. The policies identified in for managing flood risk within the wider context of the catchment. the CFMP will be delivered through a catchment. CFMPs should be used combination of different approaches. • Transportation planners. to inform planning and decision Together with our partners, we making by key stakeholders such as: • Landowners, farmers and will implement these approaches land managers who manage through a range of delivery plans, • The Environment Agency, who will and operate land for projects and actions. use the plan to guide decisions agriculture, conservation on investment in further plans, The relationship between the CFMP, and amenity purposes. projects or actions. delivery plans, strategies, projects • The public and businesses to and actions is shown in figure 1. • Regional planning bodies and enhance their understanding local authorities who can use of flood risk and how it will the plan to inform spatial be managed. planning activities and emergency planning.

Figure 1 The relationship between CFMPs, delivery plans, projects and actions

Policy planning • CFMPs and Shoreline Management Plans. • Action plans define requirement for delivery plans, projects and actions.

Policy delivery plans (see note) Projects and actions • Influence spatial planning to reduce risk • Make sure our spending delivers the best and restore floodplains. possible outcomes. • Prepare for and manage floods • Focus on risk based targets, for example (including local Flood Warning plans). numbers of households at risk. • Managing assets. • Water level management plans. • Land management and habitat creation. Note: Some plans may not be led by us – we may • Surface water management plans. identify the need and encourage their development.

Environment Agency River Douglas Catchment Flood Management Plan 3 Catchment overview

The Douglas CFMP area is located In the eastern part of the CFMP area, Ribble estuary approximately 8km in Lancashire in North West the rivers are steeper, responding downstream of Preston. England. The area is made up of quickly to rainfall. In the west, The Leeds and Liverpool Canal runs both urban and rural areas. The the catchment is flatter and rivers through the catchment. The River east of the CFMP area is dominated respond more slowly to rainfall. Douglas connects the canal and the by the larger urban settlements Land drainage within the CFMP Ribble Estuary. The area is crossed of Wigan, Chorley, Leyland and study area has been significantly by several national transport links Skelmersdale and these contain changed over time to allow including the M6 and the west coast around half of the flood risk areas. intensively managed agricultural mainline railway. In some places, There has been a decline in many land and urban areas to be created. such as in the Fluvial Yarrow policy of the traditional manufacturing Development has taken place in area, these are at risk of flooding. and related industries and some the floodplain, leading to the risk key areas have been targeted for There are locally and nationally of flooding in developed areas regeneration. The western part of important environmental sites in such as Wigan, Croston and Appley the CFMP area is mainly agricultural the CFMP area at risk of flooding. In Bridge. In many reaches the rivers land with small villages and towns. the tidal Lower Douglas, close to the have been heavily modified. Raised Here the land quality is good Ribble Estuary there is the Ribble defences have been introduced and able to support high value and Alt specially protected area, the and used widely, they reduce flood agricultural and horticultural activity Ribble and Alt Ramsar, the Ribble risk by moving water rapidly along which maintains the local economy. Estuary SSSI and the Ribble Estuary the channel and culverts. They There are currently more than 2200 NNR which have been designated prevent overtopping of the banks properties in the Douglas CFMP area for their populations of wildfowl. up to their designed standard at risk of flooding in an event with a of protection. Heavily modified 1% chance of occurring in any year. watercourses, such as culverts can (1% annual probability event (APE). increase flood risk by restricting The River Douglas has two major flow and forcing water to back up tributaries, the Rivers Yarrow behind them and possibly flow and Lostock. The headwaters out of the banks or channel. The of the Douglas and Yarrow rise floodplain of the lower Douglas on Rivington Moor. The upper and Yarrow consists of high grade catchment is characterised by the agricultural land where drainage Rivington Reservoir complex. This is modified by pumping within significantly alters the natural a complex network of artificial drainage patterns of the Douglas channels. The lower reaches of and Yarrow. These reservoirs are the Douglas are influenced by the used for public water supply and tide which controls discharge from play a strategic role in water supply a number of river tributaries of the across North West England. lower Douglas with pumped or flap outfalls. The Douglas flows into the

4 Environment Agency River Douglas Catchment Flood Management Plan Map 1 Main Features of River Douglas

Environment Agency River Douglas Catchment Flood Management Plan 5 Current and future flood risk

Overview of the current flood risk

Flood risk has two components: Woods. Rivington Reservoirs play over the surface before soaking the chance (probability) of a an important role in regulating into the ground or entering particular flood and the impact (or flow. When they are not full they a watercourse. This type of consequence) that the flood would trap water flow from the upper flooding can occur throughout have if it happened. The probability catchment and when full they the catchment but usually of a flood relates to the likelihood of slow the water flow. This reduces only causes a low level of risk. a flood of that size occurring within flood peaks on the Yarrow and Some of the problems in this a one year period, it is expressed Douglas. In urban areas, culverts catchment are due to urban as a percentage. For example, and other flow restrictions can drainage capacity. Chorley town a 1% flood has a 1% chance or make the flooding worse as flow centre experiences flooding as a probability of occurring in any one backs up behind these obstacles result of water flowing down the year, and a 0.5% flood has a 0.5% and flow out of bank or channel. streets and lack of capacity in the chance or probability of occurring in Parts of the catchment are tidally existing sewer system. any one year. The flood risks from influenced; fluvial flood risk can • Sewer flooding is usually caused the main rivers quoted in this report be made worse by tide locking. by an inadequate sewer capacity take account of flood defences River water cannot flow out to sea or blockages within the network. already in place. due to a high tide. There is a history of local flooding The Douglas catchment has a • Direct tidal flooding may occur in related to urban drainage in history of flooding but the most Hesketh Bank, where defences Chorley, Burscough and other notable events were in August 1987 can be overtopped by a very sites in the catchment . There is and October 2000 when Croston high tide and storm surge. The minor flooding in Croston thought village flooded affecting around main areas at risk from high to be caused in part by high 200 properties. The flow in 2000 tides are the floodplain on the water levels in the river backing was recorded and estimated to east bank of the Douglas next up the drains. United Utilities be the equivalent of a 0.5% APE to Tarleton (around 1.2m deep) have an ongoing programme of or 1 in 200 year event. The Yarrow and the floodplains adjacent to work to maintain and improve broke out of its banks upstream Becconsall, (up to 4m deep). public sewers. and the defences stopped the High water levels within the water returning to the river. There • Groundwater- In the Douglas Douglas Estuary may prevent have been flood events in Chorley, catchment there has been pumped or flapped outfalls Wigan and Leyland but recent flood groundwater pumping for many working correctly, leading alleviation works have mitigated the years, but this has mostly ceased to flooding behind the tidal level of property damage after more now. Some local flooding of defences; affecting mainly damaging floods in the past. property in Appley Bridge has agricultural land. Tidal flooding been reported since pumping The main sources of flooding in the and coastal processes will be stopped. There is flood risk Douglas catchment are as follows: assessed in the next Shoreline from the Rufford aquifer as Management Plan (SMP) • River flooding is mainly from the groundwater level would expected in 2010. three rivers; the Douglas affects naturally be above the surface Wigan, the Yarrow affects Croston • Surface water flooding is caused but the aquifer is covered by a and Chorley and the Lostock by water collecting or flowing thin layer of clay, which prevents affects Leyland and Whittle Le

6 Environment Agency River Douglas Catchment Flood Management Plan Where is the risk?

the groundwater flowing to the The main flood risk to people and The map overleaf illustrates where surface. communities is in Croston, parts the properties are at risk of flooding of Wigan and Appley Bridge. In in a 1% annual probability event. • Canal Flooding, there is risk from Wigan flooding can affect socially the Leeds/Liverpool canal as in We recognise the potential risk from vulnerable groups. In Croston a some places it is above the level surface water and sewer flooding. significant part of the community of the surrounding properties. Further studies, following on from is at risk together with a school, British Waterways manage this the CFMP, will be undertaken to sewage treatment works and structure. quantify this potential risk. businesses.

What is at risk? Table 1. Locations of Towns and Villages with 25 or more properties Using detailed hydraulic models at risk in a 1% annual probability river flood and flood maps on the smaller water courses where no models Number of properties at risk Locations exist we estimate there are more than 2,200 properties at risk of 500 to 1,000 In the Wigan Metropolitan Borough flooding in a 1% APE (this includes Council area at Wigan. In the Bolton some tidal flooding).There are Metropolitan Borough Council area four environmentally designated at Horwich sites and one scheduled ancient monument within the 1% annual 101 to 500 In the South Ribble Borough Council probability flood extent, some of area at Leyland. In the Chorley which could be adversely affected Borough Council area at Croston. by a flood. There is a risk to the Leeds Liverpool canal, particularly 51 to 100 In the Chorley Borough Council area in the Douglas valley between at Lostock to Whittle Le Woods Wigan and Parbold, to motorway In the Wigan Metropolitan Borough embankments and culverts and Council, West Lancashire District to rail infrastructure across the Council and Chorley Borough catchment. Urban areas are Council areas at scattered rural most affected by flooding but properties rural properties and grade one agricultural land will flood in a 1% 25 to 50 In the West Lancashire District APE. In the built up areas a few Council area at Appley Bridge areas are at risk of flooding from water deeper than 3m in a relatively small flood event, and throughout Table 2. Critical infrastructure at risk: the CFMP area there are people at risk of flooding with water deeper 1 electricity substation, 1 wastewater treatment works than 1m. This can be a risk to life.

Environment Agency River Douglas Catchment Flood Management Plan 7 Map 2 Flood Risk in the River Douglas CFMP Area

How we currently manage the risk in the catchment

The Douglas catchment has probability of flooding, and those • Identifying and promoting new benefited from engineering that address the consequences of Flood Alleviation Schemes where schemes put in place over the last flooding. appropriate, such as in Horwich, 50 years or more. These include: Wigan and the tidal villages. Activities that reduce the probability There are also studies planned • The Bannister Brook Flood of flooding include: or ongoing in Croston, Appley Alleviation Scheme completed in • Maintaining and improving Bridge, on the Tidal River Douglas 1993 has reduced the flood risk existing flood defences, and the Yarrow. for the town of Leyland. structures and watercourses. • Working with local authorities to • Construction of defences at Wigan The catchment has over 50 km of influence the location, layout and and Flood Alleviation works in raised defences, more than 55% design of new and redeveloped Whittle Le Woods and Lostock. of these are maintained by the property and ensuring that only Environment Agency. In addition to these engineering appropriate development is schemes, other flood risk • Enforcement and maintenance allowed on the floodplain through management activities are carried where riparian owners and others the application of Planning Policy out in the catchment. These include carry out work detrimental to flood Statement 25 (PPS25). activities that help to reduce the risk or neglect their duties.

8 Environment Agency River Douglas Catchment Flood Management Plan The impact of climate change and future flood risk

Activities that reduce the In the future, flooding will be In the Douglas CFMP area, the consequences of flooding include: influenced by climate change, shape of the river valleys limits changes in land use (for example the extent of flooding and in many • Flood risk mapping, urban development) and rural places the future increase in the understanding where flooding is land management. In the Douglas flooded area is likely to be small likely to occur. catchment, sensitivity testing with a increase in flood depth of • Operation of floodline and flood revealed that climate change has around 0.15m, some areas will warning services to 5 areas and the greatest impact on flood risk, see a much greater increase, for 2400 properties in the Douglas with land management change, example, Appley Bridge is predicted Catchment. and urbanisation having a smaller to see a 0.6m increase in flood effect. Whilst we do not know depth. In the future, Wigan, Croston, • Providing flood incident exactly what will happen in the Leyland to Whittle Le Woods, the management response. future the key trends are: villages of Longton, New Longton and Hutton and some rural areas, • Promoting awareness of • More frequent and intense the flooded area will be larger and flooding so that organisations, storms causing more widespread affect many extra properties. An communities and individuals are flooding from drainage systems additional 329 properties across aware of the risk and are prepared and some rivers. the CFMP area would be at risk of in case they need to take action in flooding from rivers or the sea in time of flood. • Wetter winters increasing the likelihood of large-scale flooding. a future 1% event. No additional • Promoting resilience and environmental or heritage sites are resistance measures for those The future scenarios used in the in the future 1% annual probability properties already in the Douglas CFMP were: flood extent but the flood depth and floodplain. extent of flooding is expected to • A 20% increase in peak flow in increase slightly. all watercourses. The predicted increase in flow can affect the Figure two shows the shows the frequency, timing, scale of difference between current and flooding and the flood levels. future flood risk for a 1% event at key areas in the catchment. • A total sea level rise of 841 mm by the year 2100.

Figure 2 Current and future (2100) flood risk to property from a 1% annual probability river flood, taking into account current flood defences.

1000

800

600

400

200 Number of Properties at Flood Risk at Properties Number of

0 Wigan Leyland Croston Horwich Hutton Lostock Area Rural Yarrow Appley Bridge EcclestonFluvial area DouglasRural Lostock Tidal Douglas Longton/New Longton Current Future

Environment Agency River Douglas Catchment Flood Management Plan 9 Future direction for flood risk management

Approaches in each sub-area

We have divided the Douglas not sustainable to keep building This document does set out our CFMP area into ten distinct sub- and raising defences. This is why policies for managing flood risk, areas that have similar physical we have to look catchment wide at recognising the constraints that characteristics, sources of flooding how we direct effort and resources do exist. Our future direction for and levels of risk. These sub to ensure sustainable solutions. managing flood risk is expressed areas will allow us and the key We have assessed what will be by applying one of our six standard stakeholders to promote flood the most sustainable approach policy options to that sub area. To risk management approaches, to managing flood risk in each select the most appropriate policy, policies and actions that are most sub-area. This is presented in the the plan has considered how social, appropriate in that area to deliver following sections and they outline: economic and environmental the various Government and • The key issues in that area. objectives are affected by flood risk regional strategies, in particular management activities under each “Making Space for Water”. In the • The vision and preferred policy. policy option. The six policy options face of increasing risk, it often is • The proposed actions to are explained on page 11. implement the policy. Map 3 Sub-areas

10 Environment Agency River Douglas Catchment Flood Management Plan Table 3 Policy options ➜ Policy 1 Areas of little or no flood risk where we will continue to monitor and advise This policy will tend to be applied in those areas where there are very few properties at risk of flooding. It reflects a commitment to work with the natural flood processes as far as possible.

➜ Policy 2 Areas of low to moderate flood risk where we can generally reduce existing flood risk management actions This policy will tend to be applied where the overall level of risk to people and property is low to moderate. It may no longer be value for money to focus on continuing current levels of maintenance of existing defences if we can use resources to reduce risk where there are more people at higher risk. We would therefore review the flood risk management actions being taken so that they are proportionate to the level of risk.

➜ Policy 3 Areas of low to moderate flood risk where we are generally managing existing flood risk effectively This policy will tend to be applied where the risks are currently appropriately managed and where the risk of flooding is not expected to increase significantly in the future. However, we keep our approach under review, looking for improvements and responding to new challenges or information as they emerge. We may review our approach to managing flood defences and other flood risk management actions, to ensure that we are managing efficiently and taking the best approach to managing flood risk in the longer term.

➜ Policy 4 Areas of low, moderate or high flood risk where we are already managing the flood risk effectively but where we may need to take further actions to keep pace with climate change This policy will tend to be applied where the risks are currently deemed to be appropriately-managed, but where the risk of flooding is expected to significantly rise in the future. In this case we would need to do more in the future to contain what would otherwise be increasing risk. Taking further action to reduce risk will require further appraisal to assess whether there are socially and environmentally sustainable, technically viable and economically justified options.

➜ Policy 5 Areas of moderate to high flood risk where we can generally take further action to reduce flood risk This policy will tend to be applied to those areas where the case for further action to reduce flood risk is most compelling, for example where there are many people at high risk, or where changes in the environment have already increased risk. Taking further action to reduce risk will require additional appraisal to assess whether there are socially and environmentally sustainable, technically viable and economically justified options.

➜ Policy 6 Areas of low to moderate flood risk where we will take action with others to store water or manage run-off in locations that provide overall flood risk reduction or environmental benefits This policy will tend to be applied where there may be opportunities in some locations to reduce flood risk locally or more widely in a catchment by storing water or managing run-off. The policy has been applied to an area (where the potential to apply the policy exists), but would only be implemented in specific locations within the area, after more detailed appraisal and consultation.

Environment Agency River Douglas Catchment Flood Management Plan 11 Sub-area 1

Wigan

Our key partners are: greater. Wigan generates more The key messages than 50% of the cost of flood Wigan Metropolitan Borough damage in the CFMP area. There • Finalise Flood Risk Management Council are some raised defences in Wigan scheme for Wigan. which reduce risk in smaller flood United Utilities • Continue to maintain defences events. A scheme is proposed at and major assets. British Waterways Water Heyes which will reduce flood risk from the River Douglas but this • Undertake risk assessments Highways Agency would still leave 874 properties at on culverts and other flow risk of flooding in a 1% event in restrictions. the future. There is a flood warning • Minimise inappropriate The issues in this service, but uptake of this is only 37%. development in areas at risk of sub-area flooding.

Wigan is the largest town in the • Continue with flood warning CFMP area. There is a history of The vision and programme of information and flooding in the town centre from preferred policy education. the River Douglas and from smaller watercourses elsewhere in the Policy option 5: Areas of moderate town. Wigan has seen a decline in to high flood risk where we can its traditional industry and parts generally take further action to of the town, including parts of the reduce flood risk. town centre within the floodplain Wigan is an important residential of the River Douglas, have been and industrial town and parts of the identified as regeneration areas. town are often exposed to flooding. The rivers in Wigan are restricted The proposed Water Heyes scheme by urban development including will reduce some of the risk from culverts and other structures. There the River Douglas but will still leave is a risk of flooding from surface hundreds of properties at risk of run-off, drains and sewers. Areas flooding in the future including at risk of flooding include places areas at risk from tributaries of with very high social vulnerability. the Douglas, culverts, drains and There are 961 properties at risk of sewers. Our vision is to reduce the flooding from rivers in a 1% event current level of risk in the future and the average flood depth in by targeting key areas. Reduction properties is 0.6m. Infrastructure of risk from smaller watercourses at risk includes health centres, the will involve a range of measures law court, electricity and gas sites. which may include additional Two percent of the community is defences, flood warning and sewer at risk of flooding, although this and drainage improvements. This is concentrated in particular areas will result in a safe environment in including Poolstock and Scholes which people can live and work. where the proportion is much

12 Environment Agency River Douglas Catchment Flood Management Plan Proposed actions to implement the preferred policy

The essential actions to achieve our policy aim are listed below:

• Complete Water Heyes scheme for Wigan.

• Undertake a risk assessment on culverts and other flow restrictions in the Wigan sub-area. Prioritise these structures for redesign, replacement or removal according to the flood risk. Relevant sites include, Ince Brook, Hawkley Brook and Smithy Brook.

• Develop a communication plan for reservoir maintenance and management of emergency release from Rivington reservoirs.

• Investigate the standard of protection provided by the existing main river network and seek to reduce flood risk in a sustainable way. This is likely to be achieved through maintenance works and targetted improvements to structures and river channels, but will consider other approaches where appropriate.

River Douglas through Wigan town centre

Environment Agency River Douglas Catchment Flood Management Plan 13 Sub-area 2

Appley Bridge and Croston

Our key partners are: There are some flood defences on climate change. Defences in Croston the River Yarrow in Croston which are likely to be overtopped more Wigan Metropolitan Borough reduce risk in smaller flood events frequently in the future and the risk Council and the village may benefit from in Appley Bridge is likely to increase rural defences in the surrounding as the current temporary scheme Chorley Borough Council area. Flood risk will increase in reaches the end of its life. South Ribble Borough Council the future although not by a large Our vision is to reduce the current amount. The frequency of smaller level of risk. In Croston, the West Lancashire District Council flood events may increase, as the reduction in flood risk is linked to defences are likely to be overtopped United Utilities the policy to increase flooding in more frequently. British Waterways the tidal Douglas and River Yarrow Flooding in Appley Bridge from the sub-areas. If additional flooding Highways Agency tributaries is deep (0.9m), fast onset elsewhere is unable to deliver all and fast flowing and poses a risk the reduction in flood risk required, to life. Some flooding is associated then other local measures may be with undersized culverts. There needed. In Appley Bridge, we plan The issues in this is a temporary scheme in place. to reduce risk from current levels sub-area Calico Brook is diverted into the using either the current scheme or East Quarry at times of high flow. an alternative more sustainable This sub-area contains two villages This substantially reduces risk but solutions. with similar flood risk characteristics. there have been some reports of The village of Croston is located on groundwater flooding which may the River Yarrow just upstream of its be linked to the increased water The key messages confluence with the River Lostock. level in the quarry. There is a flood • Avoid inappropriate development Appley Bridge is located on the warning service in Croston and for in areas at risk of flooding. River Douglas and Calico Brook. the River Douglas. • Investigate alternative In these two villages, 450 properties sustainable flood risk measures are at risk in a 1% APE, 406 of them The vision and for Appley Bridge and Croston. in Croston, which is one third of preferred policy the properties in the village, this • Continue to maintain existing could rise to 417 properties in Policy option 5: Areas of moderate defences. the future due to climate change. to high flood risk where we can • Undertake risk assessments Croston floods directly from generally take further action to on culverts and other flow the River Yarrow and also from reduce flood risk. culverted watercourses, drains, restrictions. sewers and surface runoff. Appley Action is required to better protect • Continue with flood warning Bridge floods at Millbank Estate these two villages from flooding programme of information and from Calico Brook, although there now and in the future. education. is some risk elsewhere in the town The risk of flooding from drains, from the River Douglas. There are sewers and surface run-off is likely 42 properties at risk in a 1% APE, to increase due to the effects of increasing to 60 in the future.

14 Environment Agency River Douglas Catchment Flood Management Plan Proposed actions to implement the preferred policy

The essential actions to achieve our policy aim are listed below:

• Carry out study for potential schemes to reduce flood risk in Croston. The study will include technical and economic investigation of a number of more local schemes which are likely to be in the Yarrow sub-area.

• Investigate alternative sustainable flood risk reduction measures for Appley Bridge, including the potential for formalising the current temporary scheme or alternative solutions.

• Undertake a risk assessment on culverts and other flow restrictions in the sub-area. Prioritise these structures for redesign, replacement or removal according to the flood risk.

• Undertake a study to improve understanding of interaction between river flow and tide in the sub-area and their impact on flood risk. The study should make use of modelling, surveys and historical information, and determine the current and future risk in Croston from combined fluvial and tidal events.

Croston Bridge Calico Brook Appley Bridge

Environment Agency River Douglas Catchment Flood Management Plan 15 Sub-area 3

Tidal River Douglas

Our key partners are: Alt Ramsar site and the Ribble This sub-area is mainly rural, with Estuary SSSI are in the flood zones some scattered properties and South Ribble Borough Council but not thought to be adversely small communities. There are affected by fluvial or tidal flooding. significant amounts of grade 1 West Lancashire District Council There are significant raised agricultural land which benefit from National Farmers’ Union defences (19.8km) in the sub-area, raised defences and pumping. Our mainly along the River Douglas, vision for the area is to ensure that Natural England which are designed to protect as much of the natural floodplain RSPB agricultural land (some of it grade as possible is restored in order to 1) and properties in Tarleton. There provide storage, reducing flooding FWAG is pumped drainage in some of the elsewhere (for example, in Croston agricultural areas. We are currently and communities within this sub- Lancashire Wildlife Trust investigating the impact of joint area) and providing environmental Defra river and tidal flood events to better benefits. Ways of achieving this understand flood risk in this area. may include managed realignment of defences and changes to the pumping operations. The issues in this The vision and sub-area preferred policy The key messages This sub-area includes the River Policy option 6: Areas of low to Douglas and its tributaries moderate flood risk where we • Investigate restoring floodplain. downstream of the tidal limit. It is will take action with others to • Improve understanding of a flat rural area, with a few small store water or manage run-off in interaction between river flow villages. Flooding occurs from locations that provide overall flood and tide. rivers and the sea. There are 13 risk reduction or environmental properties at risk of flooding in a benefits. • Identify responsibilities for 1% APE in the part of the sub-area pumping of agricultural land. that we have modelled (over 75% of properties at risk are covered by the model)and there may be other properties at risk in other parts. We estimate this could increase to 14 properties due to the effects of climate change by 2100. Infrastructure at risk includes two water treatment works. Some properties are flooded with water 1-2m deep even during small flood events. The sub-area contributes 60% of the agricultural damage in the CFMP area. Five km2 of the Ribble and Alt SPA, the Ribble and Longton Marsh

16 Environment Agency River Douglas Catchment Flood Management Plan Proposed actions to implement the preferred policy

The essential actions to achieve our policy aim are listed below:

• Undertake a study to improve understanding of interaction between river flow and tide in the downstream parts of the sub-area and their impact on flood risk. Through the use of modelling, survey and historical information, the study should determine the current and future risk from combined fluvial and tidal events. This affects communities at risk in Croston, Hesketh Bank, Becconsall, Tarleton, New Longton and Longton. There are also large areas of grade 1 agricultural land at risk from tidal and fluvial flooding.

• Carry out study to identify the responsibilities for maintaining pumping within the sub-area for agricultural drainage. The study should identify the legal responsibilities and obligations and investigate more sustainable alternatives in the long term. It must also take into account the large area of grade 1 agricultural land. The study will initiate discussions between stakeholders affected by any potential change in the pumping regime.

• Undertake study to consider restoring floodplain. This should identify areas and opportunities to restore floodplains and create habitats within the sub-area. There will be appropriate information within the Shoreline Management Plan (SMP) for the Ribble Estuary.

River Douglas in its lower reaches

Environment Agency River Douglas Catchment Flood Management Plan 17 Sub-area 4

Fluvial Yarrow

Our key partners are: The vision and Proposed actions to

West Lancashire District Council preferred policy implement the preferred policy Lancashire County Council Policy option 6: Areas of low to moderate flood risk where we The essential actions to achieve our Chorley Borough Council will take action with others to policy aim are listed below: store water or manage run-off in locations that provide overall flood • Carry out a study to investigate risk reduction or environmental suitable locations for habitat The issues in this benefits. inundation. The study should sub-area focus on reducing flooding in the The River Yarrow sub-area is mostly Croston sub-area whilst also This sub-area includes the River agricultural, with a significant identifying areas for the Yarrow and its tributaries upstream amount of grade 1 agricultural land floodplain to be reconnected, of the confluence with the River in the lower part of the sub-area. habitat improvement and Douglas. It is mainly rural, with The existing flood risk management enhancement or habitat creation. scattered properties and small measures are designed to protect The issue of good quality communities. There are 16 this agricultural land. Our vision agricultural land being flooded properties at risk in a 1% event plus for the area is to ensure that as more often must also be infrastructure, including the West much of the natural floodplain as addressed. Coast mainline railway. The main possible is restored in order to flood risk is from rivers. Current provide storage, reducing flooding • Undertake a study to improve flood risk is low and future changes elsewhere (for example, in Croston) understanding of interaction in flood risk are likely to be small. and providing environmental between river flow and tide in the There are some defences in the benefits. The existing defences in downstream parts of the sub-area lower reaches of the sub-area. the sub-area are likely to remain, and their impact on flood risk. These protect agricultural land, although alternative actions may be Through the use of modelling, some of it high grade. The defences proposed for some defences as part survey and historical information, may also have some influence on of schemes to increase flooding of this should determine the current the flow regime in Croston. There is suitable areas. and future risk from combined a flood risk (very small) associated fluvial and tidal events. The with Rivington Reservoirs which effects of the River Yarrow and its release water to the River Douglas, The key messages tributaries on Croston should be rapid releases from the reservoir identified. (eg, to allow urgent maintenance • Investigate restoring the • Develop a communication plan work) may cause local flooding floodplain where possible. for reservoir maintenance and close to the reservoir, particularly • Develop a communication plan management of emergency if they occur during a wet period. for Rivington reservoir. release from Rivington reservoirs. The Environment Agency works with United Utilities to ensure any such • Improve understanding of release of water does not unduly interaction between rivers and increase flood risk. the tide.

18 Environment Agency River Douglas Catchment Flood Management Plan Sub-area 5

Leyland and Lostock to Whittle Le Woods

Our key partners are: The vision and • Undertake risk assessments preferred policy on culverts and other flow South Ribble Borough Council restrictions. Chorley Borough Council Policy option 4: Areas of low, moderate or high flood risk where Lancashire County Council we are already managing the flood Proposed actions to risk effectively but where we may British Waterways implement the preferred need to take further actions to keep policy Highways Agency pace with climate change. The essential actions to achieve our United Utilities This sub-area covers Leyland and policy aim are listed below: smaller towns between Lostock and Whittle Le Woods. With the • Undertake a risk assessment on effects of climate change, the flood culverts and other flow The issues in this risk in these towns will increase restrictions in the sub-area. sub-area (66 additional properties at risk Prioritise these structures for of flooding from rivers and a 0.6m redesign, replacement or removal This sub-area contains the towns increase in the average flood depth according to the flood risk. of Leyland, Lostock, Clayton in properties). Our vision for this Relevant sites include Bannister Brook, Clayton Green and Whittle sub-area is to take targeted action Brook, Bryning Brook, Wade Le Woods. These are in the River as necessary to sustain the current Brook Mill Brook and the River Lostock catchment. Flooding is from level of flood risk. This may include Lostock. the River Lostock and tributaries the introduction of a flood warning including Bannister Brook and Wade service, improvements to drainage • Investigate the standard of Brook in Leyland and Carr Brook network and sewer systems, protection provided by the in Whittle Le Woods. There are increased channel and structure existing main river network and 180 properties at risk of flooding maintenance, opening up of seek to reduce flood risk in a from rivers. There is also localised channels in places where flooding sustainable way. This is likely to flooding from culvert restrictions is due to flow restrictions, and be achieved through and from surface water, drains additional or improved defences. maintenance works and targetted and sewers. There is a culverted improvements to structures and defence scheme on Bannister Brook river channels, but will consider and maintained channel sections in The key messages other approaches where Whittle Le Woods. appropriate. • Continue to maintain our existing defences.

• Investigate and address the causes of urban drainage flooding.

Environment Agency River Douglas Catchment Flood Management Plan 19 Sub-area 6

Horwich

Our key partners are: The issues in this The vision and

Bolton Metropolitan Borough sub-area preferred policy Council Horwich is a small town on the edge Policy option 4: Areas of low, moderate or high flood risk where Highways Agency of Rivington Moor in the upper part of the Douglas catchment. There we are already managing the flood United Utilities is a risk of flooding in the town risk effectively but where we may from the River Douglas and its need to take further actions to keep tributaries, Pearl Brook and Nellies pace with climate change. Clough. A third of the properties Our flood zones have identified at risk of flooding from rivers are 510 properties at risk of flooding in non-residential. Horwich generates Horwich (9% of property in the sub- 21% of the annual average damage area). As the climate changes, an from river flooding in the CFMP extra 55 properties may be at risk of area. There is some flood risk (very flooding. Our vision for this sub- small) associated with Rivington area is that we will continue with Reservoirs which release water to our existing flood risk management the River Douglas just upstream of actions and we will monitor change Horwich. Rapid releases from the in flood risk and take action as it is reservoir (eg, to allow maintenance needed. This will involve targeted work) may increase flood risk actions and may include extending particularly if they occur during the flood warning area to include a wet period. The Environment properties at risk from Pearl Brook Agency works with United Utilities and Nellies Clough (may be difficult to ensure any such releases do not to achieve required lead times), unduly increase flood risk. There is improvements to drainage and also a risk of flooding from surface sewer networks, additional or runoff, drains and sewers. A culvert improved defences. blockage study has been completed as part of the Horwich SFRM and this has identified flow restrictions The key messages for repair or replacement. • Continue to maintain our existing defences. There are some raised defences on the River Douglas immediately • Undertake risk assessments on downstream of Horwich and work culverts and other flow restrictions. is in progress to implement a flood warning service. • Continue with flood warning and the programme of information and education.

• Carry out study to improve understanding of sources of flood risk in the sub-area.

20 Environment Agency River Douglas Catchment Flood Management Plan Proposed actions to implement the preferred policy

The essential actions to achieve our policy aim are listed below:

• Using information provided from the Horwich Strategic Flood Risk Management plan, produce a prioritised list of structures for redesign or replacement according to the flood risk.

• Develop a communication plan for reservoir maintenance and management of emergency release from Rivington reservoirs.

• Work in partnership with Bolton MBC and United Utilities over sewer and local surface water flooding. Identify and promote joint solutions where surface water and sewer flooding is known to exist.

• Completed river model outline for Horwich (River Douglas, Pearl Brook and Jepson’s Clough). This will reduce some of the uncertainty of the current risk information from our flood zones.

• Encourage the use of appropriately designed Sustainable Drainage Systems (SUDS) to control run-off at source.

River Douglas in Horwich

Environment Agency River Douglas Catchment Flood Management Plan 21 Sub-area 7

Tidal Villages

Our key partners are: The vision and Proposed actions to

Lancashire County Council preferred policy implement the preferred policy South Ribble Borough Council Policy option 4: Areas of low, moderate or high flood risk where The essential actions to achieve our we are already managing the flood policy aim are listed below: risk effectively but where we may The issues in this need to take further actions to keep • Using information provided from sub-area pace with climate change. the Hall Pool strategic flood risk assessment to produce a The communities in this sub- This sub-area includes the villages prioritised list of structures for area are at risk of flooding from of Longton, New Longton, Hutton, redesign or replacement both rivers and the sea. Existing Becconsall, Hesketh Bank and according to the flood risk. management activities including Tarleton which are all in the flat Prioritise structures in Hesketh the Hesketh Bank tidal flood tidal part of the CFMP area. They Bank, Becconsall and Tarleton for warning area and maintenance of are at risk of flooding from the redesign, replacement or removal drainage and sewer networks will River Douglas (Becconsall, Hesketh following an assessment of their continue. As risk increases in the Bank and Tarleton), Longton Brook flood risk. future due to climate change, we (Hutton) and Hall Pool (Longton). will take targeted actions. These • Work in partnership with the local There are currently 23 properties at could include offering a direct flood authority and United Utilities over risk of flooding in a 1% event, but warning service for Hesketh Bank sewer and local surface water this may increase to more than 200 and Tarleton tidal flood warning area flooding. Identify and promote additional properties at risk in the and a fluvial/ tidal flood warning joint solutions where surface future. There is a risk of flooding service in Longton, New Longton water and sewer flooding is from the sea. There is also a risk and Hutton, and improvements to known to exist. of flooding from surface run-off, drainage network and additional or drains and sewers. Defences in the improved defences. This sub-area • Continue with an inspection and Tidal Douglas sub-area reduce risk may see a reduction in flood risk in maintenance regime but ensure in these villages. These include the future associated with actions work is in line with best value, defences on the River Douglas taken in the tidal Douglas sub-area. risk based asset management next to Tarleton, sea defences at plans. Hesketh Marsh and Hesketh Bank • Investigate the standard of and defences on tributaries of Hall The key messages Brook and Longton Brook. We are protection provided by the investigating the consequences • Continue to maintain existing existing main river network and of a joint river/tidal flood event, defences in surrounding area. seek to reduce flood risk in a to better understand the risk of sustainable way. This is likely to • Investigate the impact of tidal flooding in this area. The flat be achieved through and fluvial events in this sub- topography means that the number maintenance works and targeted area. of properties at risk could increase improvements to structures and river channels, but will consider substantially in more extreme flood • Undertake risk assessment other approaches where events. on culverts and other flow restrictions. appropriate.

22 Environment Agency River Douglas Catchment Flood Management Plan Sub-area 8

Rivington

Our key partners are: risk is from small watercourses, in the future. We will monitor the three properties at risk. We do not reservoir as part of our actions for Chorley Borough Council currently carry out any flood risk downstream sub-areas. Our vision management activities in this sub- will be achieved under our preferred Bolton Metropolitan Borough area. Flood risk is very low and is approach of policy 1. Council not expected to change significantly in the future. The key messages The issues in this The vision and • Monitor operation of Rivington sub-area Reservoir. preferred policy The Rivington sub-area is located • Monitor and advise on the in the east of the CFMP area and Policy option 1: Areas of little or no moorland grip project at contains Rivington reservoirs and flood risk where we will continue to Anglezarke. their catchments. The sub-area is monitor and advise. rural and includes moorland areas This is a rural area, we do not around Rivington, with scattered currently carry out any flood risk Proposed actions to properties and small communities. management activities and our Apart from the reservoir and its implement the preferred vision for this area is that this main catchwater, the sub-area policy will continue. This is unlikely to is fairly natural. The main flood lead to an increase in flood risk The essential actions to achieve our policy aim are listed below:

• Monitor the communication plan developed by United Utilities for reservoir maintenance and management of emergency release from Rivington reservoir.

• Identify any monitoring information available and its quality following the moorland grip blocking project on Anglezarke moor. This project's objective is to reduce run-off in parts of the upper catchment by blocking drainage channels cut in the peat. It is hoped this will reduce flood risk further downstream in the catchment.

Rivington Reservoir

Environment Agency River Douglas Catchment Flood Management Plan 23 Sub-area 9

(Fluvial) River Douglas

Our key partners are: property and high grade agricultural needed. The increase in risk may land mostly in the Abbey/ Eller be scattered around the sub- South Ribble Borough Council Brooks and River Tawd catchments. area and may require a range of In the built up areas there will also actions. Maintenance of defences, West Lancashire District Council be a increase in flood risk in the channels, structures and the urban Chorley Borough Council future associated with urban runoff drainage network will continue. and channel restrictions which may We may consider improved land Wigan Metropolitan Borough not be able to cope with the intense management (including targeted Council rainfall events which are expected flooding of additional areas, if Lancashire County Council to become more frequent. Flood appropriate), flood resilience in defences in the lower part of the properties or localised defences Highways Agency sub-area protect agricultural land and flood warning. In built-up and rural property. There is some areas, measures could include United Utilities flood risk associated with rapid improvements to the urban British Waterways releases from Rivington Reservoirs, drainage network, increased to allow maintenance work, which channel and structure maintenance may increase flood risk, particularly and opening up channels where if they occur during a wet period. restrictions are leading to flooding. The issues in this The Environment Agency is working There may be a reduction of risk sub-area with United Utilities to ensure in the downstream part of this any such releases do not unduly sub-area as a consequence of our The River Douglas sub-area covers increase flood risk. actions in the River Yarrow and tidal the River Douglas between the Douglas sub-areas. outlet of Rivington Reservoir and the tidal limit at Rufford. In the The vision and rural areas, the main flood risk is The key messages from rivers. In the built-up areas, preferred policy the risk is mainly associated with Policy option 4: Areas of low, • Continue to maintain defences culverts and other flow restrictions. moderate or high flood risk where and major assets. There is also a flood risk in the we are already managing the flood • Undertake risk assessments built up areas from surface run-off, risk effectively but where we may on culverts and other flow drains and sewers. There are 68 need to take further actions to keep restrictions. rural properties at risk of flooding pace with climate change. from rivers and there may be an • Investigate alternative actions to additional 21 properties at risk in This sub-area covers both towns manage flood risk at the current the future. Critical infrastructure at and rural areas in the Douglas level in the future. risk of flooding includes electricity Valley. With the effects of climate supply sites and a water treatment change, the flood risk will increase • Avoid inappropriate development works. The sub-area contributes particularly in the urban areas in areas at risk from flooding. 23% of the total agricultural (21 additional properties at risk • Continue with flood warning damage in the CFMP area. Risk is of flooding from rivers). Our programme of information and forecast to increase in the future, vision for this sub-area is that education. with additional flooding of rural we will take targeted action as

24 Environment Agency River Douglas Catchment Flood Management Plan Proposed actions to implement the preferred policy

The essential actions to achieve our policy aim are listed below:

• Develop a communication plan for reservoir maintenance and management of emergency release from Rivington reservoirs.

• Undertake a risk assessment on culverts and other flow restrictions in the sub-area. Prioritise these structures for redesign, replacement or removal according to the flood risk. Relevant sites include the River Tawd and Abbey Brook.

• Investigate the standard of protection provided by the existing main river network and seek to reduce flood risk in a sustainable way. This is likely to be achieved through maintenance works and targeted improvements to structures and river channels, but will consider other approaches where appropriate.

• Encourage partner organisations to collaborate to produce Surface Water Management Plan to better manage flooding in key urban locations such as Skelmersdale, Burscough, Parbold and Standish.

River Douglas at Wanesblades Bridge

Environment Agency River Douglas Catchment Flood Management Plan 25 Sub-area 10

Rural Lostock and Yarrow Communities

Our key partners are: place, mostly to protect agricultural then consider alternative more land. sustainable measures in the rural Chorley Borough Council areas. We will achieve this vision under our preferred approach of Wigan Metropolitan Borough policy three. Council The vision and preferred policy South Ribble Borough Council Policy option 3: Areas of low to The key messages moderate flood risk where we are generally managing existing flood • Continue to maintain our existing The issues in this risk effectively. assets. sub-area The routine and reactive • Investigate and address the This sub-area includes the maintenance work which we and causes of urban drainage town of Chorley and the smaller our partners (including the local flooding. communities of Euxton, Eccleston, authority, United Utilities and • Undertake risk assessments Heskin Green and Wrightington Bar Network Rail) carry out plays a on culverts and other flow on the River Yarrow catchment and key role in managing flood risk in restrictions. the rural area of the River Lostock this sub-area. The current level and its tributaries upstream of its of maintenance work however in • Improve understanding of confluence with the Yarrow. the rural areas of the Lostock is interaction between river flow and the tide in the downstream In total there are 22 properties at low. Our vision is to continue with parts of the sub-area. risk in a 1% APE. Current flood risk this work to manage risk at the current level. We may consider is low and future changes (by 2100) • Investigate alternative actions to alternative more sustainable in flood risk are likely to be small maintain risk at the current level measures if appropriate. If further (3-4 properties). in the future. work identifies that the defences Chorley has a history of flooding do not have a significant impact • Avoid inappropriate development from surface water. The town is on flood risk in Croston, we may in areas at risk of flooding. located on the side of a hill and water flows down to the River Chor in the valley. The river is culverted and surface flow ponds behind restrictions, including the railway embankment. Flood risk will increase in the future, particularly associated with urban drainage.

In the rural areas of the Lostock, eight properties are at risk from river flooding. Some defences are in River Lostock at Littlewood Bridge Gauging Station

26 Environment Agency River Douglas Catchment Flood Management Plan Proposed actions to implement the preferred policy

The essential actions to achieve our policy aim are listed below:

• Investigate the standard of protection provided by the existing main river network and seek to reduce flood risk in a sustainable way. This is likely to be achieved through maintenance works and targeted improvements to structures and river channels, but will consider other approaches where appropriate.

• Work in partnership with the local authority and United Utilities to address sewer and local surface water flooding and promote joint solutions where surface water and sewer flooding is known to exist.

• Develop a communication plan for reservoir maintenance and management of emergency release from Rivington reservoirs.

• Undertake a study to improve understanding of interaction between river flow and tide in the downstream parts of the sub-area and their impact on flood risk. Determine current and future risk to property and high grade agricultural land from combined events.

• Investigate opportunities to remove or realign embankments, create flood storage areas or other alternative means of flood risk management. Changes in land use may provide flood risk benefits and create habitat.

Syd Brook at Eccleston

Environment Agency River Douglas Catchment Flood Management Plan 27 Map of CFMP policies

28 Environment Agency River Douglas Catchment Flood Management Plan

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