01 09 Strategic Environmental Assessment

RRFRMS Statement of Environmental Particulars Statement of environmental particulars for the River Roding Flood Risk Management Strategy Purpose Introduction This statement of environmental particulars shows how environmental considerations and consultation comments were taken into account during the preparation of the River Roding Flood Risk Management Strategy (RRFRMS) and how the Environment Agency selected the approach adopted in the final Strategy. The statement sets out the monitoring procedures that have been set in place to monitor the significant environmental effects of implementing the RRFRMS. The statement also sets out the work undertaken to finalise the strategy following the consultation on the draft strategy. In 2006 a draft of the RRFRMS was sent out to consultation. Since this consultation, a series of changes have been made on economic and sustainability grounds, leading to a revised strategy and an addendum to the Strategic Environmental Assessment (SEA). A further round of consultation was undertaken in 2011 on the draft revised RRFRMS and supporting SEA Addendum. This statement of environmental particulars outlines the environmental effects of the strategy and how consultation has affected the final plan. Integration of environmental considerations Environmental considerations were integrated throughout the development of this plan. Following the Environment Agency’s Strategic Environmental Assessment (SEA) operational instruction, our National Environmental Assessment Service (NEAS) worked with the project team from the beginning of the strategy. Working in this way, many potential significant effects of the strategy on the environment were avoided and others mitigated through the strategy development. Plan history The River Roding flows from Molehill Green in the North to the A12 south of Wanstead in the South (Figure 1). We have developed a plan to manage flooding from rivers and surface water adjacent to the River Roding. In 2006, a draft flood risk management strategy and SEA (documented in the SEA Environmental Report) was presented to the public, statutory and wider stakeholders for their comments. This iteration of the RRFRMS aimed to continue maintaining the existing flood risk management system and provide additional protection through a series of flood water storage areas. Since the 2006 consultation, we have been investigating the River Roding catchment as a series of flood cells, as shown on Figure 1. The options have become more focussed to each particular cell, leading to some changes from the 2006 draft strategy. The main changes are summarised below: • The surface water flood storage area protecting Woodford has been moved from Ray Park to Broadmead, Chigwell Road. • Surface water pumping forms part of the new preferred Strategy in Woodford. • A flood storage area (FSA) at Shonks Mill is still part of the preferred Strategy, however this would now be constructed by 2020 and will be larger than proposed in 2006. • Withdrawal of maintenance of the river channel in areas upstream of the Shonks Mill FSA where it is no longer economically viable to continue these works. • Withdrawal of maintenance where the cost of maintaining existing defences to their current standard outweighs the benefits provided. Doc No 01_09 Version 2 Last printed 03/06/14 Page 1 of 19 RRFRMS Statement of Environmental Particulars Figure 1: Location and Flood Cells Doc No 01_09 Version 2 Last printed 03/06/14 Page 2 of 19 RRFRMS Statement of Environmental Particulars Influence of the Strategic Environmental Assessment The The 2006 draft strategy was assessed using three catchment wide options. The environment strategy approach changed to one based on separate flood cells in the River Roding during Flood Risk Management Strategy Review. The SEA was revisited and an addendum development of was produced to document the revised assessment. The main change was the the plan ability to adopt different approaches in different parts of the river. The final RRFRMS contains three main recommendations, each with different environmental impacts. The strands are: • Withdrawal of maintenance • Continue current activities • Construction of new flood water storage areas The SEA assessed the potential impacts associated with each of these strands and influenced the choices for structural options. The SEA Addendum was open to public consultation and influenced the development of the strategy by identifying environmental enhancements and setting out requirements for mitigation, where significant negative impacts were identified. The environmental benefit of withdrawing maintenance in certain reaches of the river has been the main environmental change between the 2006 and 2011 strategies. Table 1 below provides a summary of the predicted environmental effects (those with a potential moderate or major impact) of the RRFRMS and the proposed mitigation measures planned to minimise the impact of these effects. Developments implemented as a result of the strategy will be assessed for environmental impacts at a project level, using the Environment Agency’s Environmental Impact Assessment (EIA) operational instruction. A Glossary of Terms can be found on page 14 of this report. Doc No 01_09 Version 2 Last printed 03/06/14 Page 3 of 19 RRFRMS Statement of Environmental Particulars Table 1: Environmental Effects of RRFRMS and Proposed Mitigation/Enhancement measures: No Active Intervention (Withdrawal of all maintenance), Mainly Upper Catchment Flood Cells 1, 2, 4, 5, 6, 13, 14, 15, 16 and 17 (see figure 1) Environmental Potential Impact Agreed Mitigation ▲ / Enhancement activity ■ Responsibility for Topic implementation Hydrology Increased flow variability and natural processes. Contribute towards WFD mitigation measure ‘increase in-channel Environment Agency morphological diversity’ as ‘do nothing’ allows natural processes to take place, increasing localised flow variability and small scale morphological diversity in the channel ■ Flora and Fauna Increase in biodiversity through increased habitat and flow Opportunities for freshwater habitat creation to improve diversity of Environment Agency variability and reconnection with floodplain. habitats - a priority list has been determined, but will require Opportunities through: Siltation and vegetation succession will lead to increased external funding ■ Wildlife Trusts, Local variability of riparian vegetation and diversity of flow patterns. Potential to contribute towards WFD mitigation measure ‘preserve Authorities, Potential Flooding may alter a range of local sites of nature and where possible enhance ecological value of marginal aquatic Developers conservation and BAP habitats. However, there will be habitat, banks and riparian zone’ ■ minimal increases in risk flood risk. Landscape and A lack of effective drainage would create areas of wetland in Can contribute toward improving biodiversity ■ N/A visual amenity the upper Roding changing the landscape. Water and Land Deliberate flooding of contaminated land may cause Where known areas of contaminated land are to be flooded, Environment Agency Quality contaminated sediments to move, or contaminants to enter undertake surveys to determine nature of contaminants and watercourses. identify potential impacts and remedial strategies ▲ Increased inundation and potential loss of quality agricultural Potential for environmental stewardship schemes near freshwater Land Owners land as lack of effective drainage would create areas of areas, thereby improving sustainable land use ■ wetland. Continue current regime , Mainly Lower Catchment Maintain existing defences and channel Flood Cells 3, 8, 18 (see figure 1); Maintain channel only Flood Cells 7, 9, 10, 11 and 12 (see figure 1) Environmental Potential Impact Agreed Mitigation ▲ /Enhancement activity ■ Responsibility for Topic implementation Hydrology Maintenance works will mobilise nutrients within the river Works will be in accordance with Environment Agency Pollution Environment Agency channel and temporarily reduce light penetration – potential Prevention Guidelines ▲ Doc No 01_09 Version 2 Last printed 03/06/14 Page 4 of 19 RRFRMS Statement of Environmental Particulars intermittent water quality impacts Flora and Fauna Intermittent maintenance impacts on designated areas and Best practice techniques for river maintenance; Consultation, Environment Agency BAP habitats. ecology surveys and careful timing should minimise impacts ▲ Opportunities through: Will intermittently affect biological elements and chemical Undertake further surveys to identify presence of BAP species Wildlife Trusts, Local (supporting) elements of water quality in the river during heavy and implement mitigation measures if necessary ▲ Authorities, Potential maintenance (silt removal). Developers Opportunities for freshwater habitat creation to improve diversity Intermittent disturbance may encourage the spread of several of habitats. A priority list has been determined, but will require invasive species external funding ■ Recreation and Construction may cause closure/ diversion of PRoW. Agree diversions with Local Authority ▲ Environment Agency amenity Water and Land Water quality impacts from intermittent disturbance to riverbed Works will be in accordance with Environment Agency Pollution Environment Agency Quality during defence improvement Potential intermittent disturbance Prevention Guidelines ▲ to contaminated land. Where known areas of contaminated land are to be disturbed Maintenance works are unlikely to disturb

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