Item 4 Glasgow City Council 20 September 2007 Executive Committee 20 September 2007 Report by Executive Member for Land and Environment Contact Robert Booth on ext 79100 RIVER CLYDE FLOOD MANAGEMENT STRATEGY PROGRESS REPORT AND PRESENTATION OF RIVER CORRIDOR SUPPLEMENTARY DEVELOPMENT GUIDE Purpose of Report The purpose of this report is to advise Committee of the progress of the River Clyde Flood Management Strategy commission and to present, for approval, the River Corridor Supplementary Development Guide. Recommendations I recommend that Committee: i) notes the progress of the River Clyde Flood management Strategy project; and, ii) Approves the River Corridor Supplementary Development Guide for issue as a document which gives guidance for new developments on the River Clyde. Ward No(s): Citywide: X Local member(s) advised: yes No Consulted: yes no 2 1 Introduction The aim of this report is to set out progress to date in the River Clyde Flood Management Strategy (RCFMS), the delivery mechanisms proposed and most specifically present for approval the River Corridor Supplementary Development Guide, a copy of which is attached. 2 Background to the Study The Halcrow and W.A. Fairhurst & Partners Joint Venture (HFJV) was appointed by Glasgow City Council (GCC) in May 2003 to undertake the RCFMS. The study adopted a catchment wide approach to help deliver a strategy for the council to manage flood risk along the River Clyde. The aim of RCFMS was to identify flood risk from the River Clyde within the City and beyond and to develop design solutions within Glasgow. The results of this study will play a fundamental role in supporting the regeneration of the River Clyde waterfront and demonstrates the Council’s commitment to delivering comprehensive flood defence and quay wall stability solutions in Glasgow. To develop Glasgow’s metropolitan role, it also recognises the need to deliver added value as part of this work, through high standards of urban and landscape design. The RCFMS has been formulated to provide information about the implementation of flood management solutions and quay wall improvements, whilst incorporating public open space creation and public realm improvements. 3 River Clyde Flood Management Strategy Initially there were two main issues that have driven the development of the RCFMS: • Identification of flood risks through river modelling; and • The condition assessment of quay walls. Modelling of the River Clyde has been at the heart of the RCFMS commission. Glasgow is located at the transition between the tidal influence from the sea and the fluvial influence from one of the largest river catchments in Scotland. The River Clyde has been historically engineered to allow navigation. Flood risk has become more and more prominent recently with the impact of climate change, new national planning legislation, and also a number of recent flood events. At inception it was considered that a robust hydraulic model of the River Clyde was required that could withstand scrutiny and deliver detailed flood maps to identify which areas are at risk of flooding and at which return periods, setting out the impacts of climate change. Progressing from this robust assessment the RCFMS then considered the most sustainable mechanisms for managing flood risk. The RCFMS developed a robust model and an extensive exercise was undertaken to upgrade a previous model, taking into account new ground survey data (LiDAR), new bathymetry data, new hydraulic boundary conditions and extensive calibration, considering joint probability of tides and flows. The impact of climate change was also fully considered in the model, based on UKCIP2002 scenarios, the most up to date methodology recognised for this purpose. The model has been independently audited and is fully documented in the Hydrodynamic Modelling Report (June 2005). 3 This base data and the model itself has been shared with and used by a number of other organisations including the Scottish Environmental Protection Agency (SEPA), who have adopted the outcomes of the RCFMS as part of their national flood maps. Developing from the outcomes of the model, a number of potential flood management options were considered and tested as follows: • Local defences; • Catchment storage; • Downstream tidal barrier; and • Tidal barrier with upstream storage. Direct local defence was adopted as the preferred option as it represents the lowest cost and operational risk solution, whilst also being the only option that can also address issues of quay wall stability. It was also considered at an early stage in the process that delivery of direct defenses would also provide an opportunity to improve integration within the urban landscape, public realm, Clyde walkway and new developments along river, therefore achieving best fit with the City Plan. Most importantly the delivery of direct defenses is within the control of the Council. This strategy was approved by Policy and Resources Committee in March 2005. As previously stated, the stability of quay walls is directly and intrinsically linked to a flood risk management strategy. 41km of quay walls and river banks have been inspected and their stability analysed as part of RCFMS. As part of this work historical analysis was undertaken along with visual inspections where major and minor defects were recorded and stability analysis undertaken. This analysis identified the locations of poor/very poor condition and it was evident that few areas of quay wall meet current design standards. The outcomes of this study were produced in the Condition Assessment Report (March 2005). Detailed / generic engineering solutions were then considered and a preferred palette of solutions recommended that range from stabilisation using ballast, to quay wall reconstruction and introduction of new public spaces. Throughout the modelling exercise and the option appraisal the RCFMS project has fully considered a number of planning and environmental considerations that have led to the delivery mechanisms now proposed. As a result of the comprehensive approach two main delivery mechanisms were proposed, (1) direct work by the Council and (2) delivery via robust planning policy. 3.1 Direct Work proposed by Council As part of work considered to be delivered by the Council, three areas in need of early action were considered due to the associated flood risk, concern in relation to quay wall stability and the land being under control of the Council. Initial designs for the three areas were provided and proposals costed in budget terms. The three areas considered were Pointhouse Quay, Lancefield and Anderston Quay and Govan Wharf. In May 2005 the Early Action Areas Report was issued and each site has progressed on an individual basis. 4 Pointhouse Quay is now under construction and will enable the regeneration of the area. Lancefield and Anderston Quay is currently subject to a planning application which is awaiting determination but due to commence on site in line with the construction program of Fastlink. As part of the preparation of the planning application for this area detailed public consultation was undertaken in conjunction with the Fastlink proposals and the RCFMS project as a whole. Work in relation to Govan Wharf has not progressed to detailed design as there are issues of land ownership to be resolved. 3.2 Delivering via robust planning policy Moving forward from the early action areas the RCFMS has also considered fourteen other areas and produced generic engineering designs in the River Edge Treatment Report issued in January 2006. The production of the Early Action Areas and River Edge Treatment report allowed detailed design issues to be fully considered and identified the difficult constraints that exist. This process has informed the production of planning policy for the river corridor and as a result the policy produced as part of the RCFMS has a sound and robust evidence base. From an early stage in the RCFMS it was identified that comprehensive planning policy is needed to ensure each development provides appropriate direct flood defences and address quay wall stability. With no such policy in place there is no requirement for developers or public organisations to provide these essential works. This is the key aim of the document whilst also providing added value through the delivery of improved public realm throughout the river corridor. Early discussions with Development and Regeneration Services have taken place the policy is now being delivered through a Supplementary Development Guide (SDG). Although the SDG is a standalone document, it is directly linked to the emerging City Plan 2 through policy ENV5, and as a result when approved by the Council, will become a material consideration in the determination of all planning applications. The RCFMS SDG provides information about the implementation of flood management solutions and improvements to quay walls, incorporating the creation of and improvements to public spaces along the Clyde corridor. It focuses on a Co-ordinated approach which will help to achieve design excellence along the River Clyde. This development guide proposes land use policy ‘development criteria’ to ensure that all developments, including those undertaken by the Council, progress in a strategic manner. The models undertaken as part of the flood management strategy provide the most up-to- date flood risk information. This can inform new development proposals affecting the River Clyde and the geographic extent of the SDG. Although any new development