Entec and FRM > Project experience: Anglian
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Earls Barton flood risk assessment Client: Hanson Aggregates Entec was appointed by Hanson Aggregates to prepare a Flood Risk Assessment for an extension to an existing sand and gravel quarry near Earls Barton, Northamptonshire. The area of the proposed extension lies alongside the River Nene and is at risk of flooding. A key output of this study was to map the extent and nature of the flood risk to the site itself and to ensure that the operational and final restoration phases did not result in an increase in flood risk elsewhere. An existing 1D model of the river was modified by replacing the schematised floodplain with a 2D domain whilst retaining a dynamic link between the models. A base case was established against which all operational phases were compared in the form of difference maps. These difference maps compared maximum water elevations pre-and post scheme across the floodplain and mitigation measures could then be identified to limit significant increases in downstream or upstream flood levels. Principal outputs included mapping of Zone 3b (the functional floodplain), mapping of flood ‘Hazard’ values in accordance with Defra project FD2321 and animation files using to convey the site flood risk to the client in an informative and non-technical way. |
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Coastal flood risk research and development Client: Association of British Insurers Entec was commissioned by the Association of British Insurers to undertake a study to assess the current and future risks posed by extreme storm surge events along the East Coast of England. The work concentrated on assessing levels of flood risk using a number of indicators including residential and commercial property losses and vulnerable sites (e.g. schools, ambulance/fire services, hospitals). The analysis conducted in the study indicated that the financial damages from a major coastal flood affecting Eastern England are likely to increase fourfold up to £16 billion, following a sea level rise of just 0.4m. This increase could happen as early as 2040, taking account of climate change pressures, and is relatively certain by 2080. More detailed analysis was also conducted within a series of case studies (Kingston-upon-Hull, Great Yarmouth/Lowestoft, South Essex and East London) to evaluate the likely consequences of coastal flooding upon property damages, business and transport disruption, social impacts and environmental consequences. The analysis highlighted that socio-economic effects including population movements, increased development and rising asset values could add substantially to future damage costs. In addition, the final report highlighted the likely requirement of future management policies, i.e. investment requirements for coastal and flood management spending, regional planning policy and local planning system (PPS25) which will be necessary to limit the impacts of future coastal flooding. |
Water Level Management Plans
Client: Environment Agency
Water Level Management Plans were an initiative developed in 1994 to provide a means to balance and integrate the water level requirements for a range of activities in a particular area, including agriculture, flood defence and conservation. WLMPs were prepared for conservation site areas where water levels are actively managed, such as Sites of Special Scientific Interest (SSSIs), Special Areas of Conservation (SACs) and Special Protection Areas (SPAs).
Many of the EA Anglian Region’s WLMPs were prepared during the mid-1990s, and have in some instances been overtaken by changes in legislation, site conditions and the roles of stakeholders. In addition, DEFRA had recently published new guidance on the completion of WLMPs which provided more detailed information on the requirements of a WLMP and a revised format.
Entec was commissioned by the EA to undertake a review of the suitability and validity of 25 coastal WLMPs in East Anglia, and the WLMP for the River Wensum, to determine whether they met the requirements of the new DEFRA guidance.
Following this review, the EA requested that Entec revise and re-issue seven ‘priority’ WLMPs, including that for the River Wensum. This required a detailed understanding of the current water level management at each site, and the effects of nature conservation requirements; land use; hydrology; water quality; long-term water level management objectives; constraints and impacts on adjacent ground; and alterations to infrastructure and procedures.
It also required a substantial amount of stakeholder consultation and engagement to establish the most appropriate solution for water level management in the marshland. This was particularly significant for the River Wensum, where over 40 key stakeholders were consulted on the proposals and suitable water management agreement achieved.
Humber ground water flooding
Client: Environment Agency
The project involves developing tools for groundwater and surface water management and environmental assessment covering the Chalk and Splisby Sandstone aquifers of east Lincolnshire. A number of project phases are planned including: data collation and processing; hydrogeological conceptualisation; 4R rainfall, runoff and recharge modelling; construction and calibration of a multi-layer groundwater flow model; running management scenarios; and reporting.
The first phase commenced in May 2006. Data collation was completed in early 2008 with recharge modelling and conceptualisation completing Phase 1. Phase 2 will start in late 2008 with model build followed by calibration. Management scenarios and reporting ongoing until 2010/11. During all phases the project is realising benefits to EA Anglian Northern area, for example on provision of QA'd processed datasets into the CAMS process.
