Upper Mersey 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. Published by: Environment Agency Richard Fairclough House Knutsford Road Warrington WA4 1HT Tel: 0870 8506506 Email: [email protected] www.environment-agency.gov.uk © Environment Agency All rights reserved. This document may be reproduced with prior permission of the Environment Agency. December 2009 Introduction I am pleased to introduce our summary of the Upper Mersey Catchment Flood Management Plan (CFMP). This CFMP gives an overview of the flood risk in the Upper Mersey catchment and sets out our preferred plan for sustainable flood risk management over the next 50 to 100 years. The Upper Mersey CFMP is one of 77 CFMPs for England home to approximately 1.2million people with South and Wales. Through the CFMPs, we have assessed Manchester, Stockport and Macclesfield being the inland flood risk across all of England and Wales for main urban areas. There is a history of flooding with the first time. The CFMP considers all types of inland Didsbury, Sale and Altrincham at greatest risk. Over flooding, from rivers, groundwater, surface water 2,600 residential and commercial properties are at a and tidal flooding, but not flooding directly from the 1% annual probability of flooding from rivers within sea (coastal flooding), which is covered by Shoreline the Upper Mersey catchment. This is expected to rise Management Plans (SMPs). Our coverage of surface to 2,900 properties in the future due to the effects of and groundwater is however limited due to a lack of climate change. available information. We cannot reduce flood risk on our own, we will The role of CFMPs is to establish flood risk management therefore work closely with all our partners to improve policies which will deliver sustainable flood risk the co-ordination of flood risk activities and agree management for the long term. This is essential if we the most effective way to management flood risk in are to make the right investment decisions for the the future. To develop this plan and ensure social, future and to help prepare ourselves effectively for economic and environmental issues were taken the impact of climate change. We will use CFMPs to into account we worked with, and consulted many help us target our limited resources where the risks organisations. These include: Defra, Local Authorities, are greatest. Greater Manchester District Council Officers Group, United Utilities, and the Manchester Ship Canal This CFMP identifies flood risk management policies to Company. assist all key decision makers in the catchment. It was produced through a wide consultation and appraisal This is a summary of the main CFMP document, if you process, however it is only the first step towards an need to see the full document an electronic version integrated approach to Flood Risk Management. As we can be obtained by emailing enquiries@environment- all work together to achieve our objectives, we must agency.gov.uk or alternatively paper copies can be monitor and listen to each others progress, discuss viewed at any of our offices in North West Region. what has been achieved and consider where we may need to review parts of the CFMP. The Upper Mersey catchment is made up of the Rivers Mersey, Tame, Goyt, Bollin and Sinderland Brook. The catchment has a mix of predominantly rural uplands Tony Dean with the lower catchment highly urbanised. It is Regional Director Environment Agency Upper Mersey 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 Peak District 12 2 Bollin 14 3 Tame 15 4 Mersey 16 5 Upper Sinderland 18 6 Goyt 20 7 Etherow 22 8 Lower Sinderland 24 Map of CFMP policies 26 2 Environment Agency Upper Mersey 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 Upper Mersey Catchment Flood Management Plan 3 Catchment overview It is useful to draw out some catchment has a history of flooding an essential part of flood risk general characteristics that are with Didsbury, Sale and Altrincham management in the future. most important in our management at greatest risk. The Manchester, Stockport, of flood risk. The Upper Mersey The watercourses within the Upper Tameside and Trafford districts catchment is made up of the Rivers Mersey CFMP catchment have been contain a total combined population Mersey, Tame, Goyt, Bollin and extensively modified. In urban of 830,000. This is approximately Sinderland Brook. The catchment areas, many watercourses have 70% of the total population in covers approximately 1,052km2 been culverted or channelised the Upper Mersey CFMP area. and has a mix of predominantly through development. Some Our approach to management in rural uplands with the lower upstream reaches retain a more these locations is focussed around catchment highly urbanised. natural character. Reservoirs in sustainable re-development, flood The catchment extends from the the Tame, Goyt and Etherow sub- warning, resilience and "Making Pennines at its eastern boundary to catchments have an influence Space for Water" either locally or the confluence of the Bollin and the on flows within the catchment, upstream. Manchester Ship Canal in the west. particularly in the upper reaches. The northern boundary principally The CFMP area is important for The Manchester Ship Canal receives comprises the periphery of the nature conservation. Four areas waters from both the Upper Mersey Greater Manchester conurbation of special scientific interest are and River Irwell catchments and whilst the Cheshire Plains are within the floodplain. For example, provides an important drainage and located along the southern the Peak District National Park flood alleviation function. boundary. The catchment is home has many watercourses and is to approximately 1.2million people In the Mersey catchment there a dynamic system and provides with South Manchester, Stockport are operational washlands which opportunities to store water and/or and Macclesfield being the main provide a valuable flood risk manage run-off to reduce flood risk urban areas, 27% of the catchment management function and these downstream as well as improving is classified as urban. The assets will continue to form natural habitat locally. Sinderland Brook, Sale 4 Environment Agency Upper Mersey Catchment Flood Management Plan Map 1 Upper Mersey CFMP – main features Baguley Brook, Wythenshawe Environment Agency Upper Mersey Catchment Flood Management Plan 5 Current and future flood risk Overview of the current flood risk Flood risk has two components: • River flooding can occur in available on surface water the chance (probability) of a the upper and lower parts of flooding and further work is being particular flood and the impact (or the catchment. In the upper undertaken to assess its true consequence) that the flood would catchment, the Tame, flows extent. have if it happened. The probability through a steep and heavily • Sewer flooding is known to of a flood relates to the likelihood of urbanised area. Uppermill, have affected houses internally a flood of that size occurring within Mossley, Stalybridge and in Heaton Moor, Stretford and a one year period, it is expressed Dukinfield are at flood risk in a Altrincham. United Utilities have as a percentage. For example, 2% event. The Goyt and Etherow an ongoing programme of work a 1% flood has a 1% chance or flow through more rural areas. to maintain and improve public probability of occurring in any one The response times of these sewers.