Natural Asset Sub-catchment Approach to Surface Water Management

The Brandon and Area Planning District (BAPD) - a partnership between the City of Brandon, the Rural Municipality of Cornwallis and the Rural Municipality of Elton - will conduct an operational study to determine how to manage surface water run-off through maximizing the use of natural assets on a sub-catchment basin. The region experienced two floods of record of the Assiniboine River (spring 2011 and summer 2014), and flash flooding of public and private property due to severe downpours of summer rains between 2005 and 2011. The study will: 1. Evaluate the potential to harmonize surface water management polices used by the district members, identifying similarities and gaps and recommending a way forward to a BAPD stormwater management strategy that maximizes the use of natural drainage feature assets.2. Using the information contained in the BAPD Development Plan, the BAPD Fringe Area Growth Strategy, the South Brandon Annexation Proposal and acquired LiDAR data, identify the surface water sub-catchments, which connect to the Little Souris River, Willow Creek and Little Willow Creek catchments.3. Within the sub-catchments, inventory and assess the general condition of the natural drainage management features such as wetlands, coulees, streams and of the civil infrastructure features such as road ditches, culverts and bridges. Using a computer model, analyze the natural assets and the civil infrastructure for impacts of present day surface water flows and the impacts of future surface water flows resulting from land feature changes due to both urban and rural growth under conditions of maximum and minimum use of natural drainage asset features.4. Develop and implement a computer generated hydrological and hydraulic model for each sub-catchment to determine runoff hydrographs, and stream reach and pond routing over a number of scenarios for present conditions and for known urbanization activity areas which will send future urban runoff flows through the natural conveyance systems in the rural municipalities.5. Identify and prioritize a system of natural assets to be protected from the adverse influences of rural and/or urban surface water runoff relating to land development and meteorological events.The ultimate goal of this study is to provide a formal process for the Planning District Board to use when development proposals come forward. The process will help maximize the use of natural drainage assets while assessing the impacts and establishing mitigation requirements needed to minimize the adverse impacts of surface water runoff on the natural land drainage system, on the civil infrastructure and upon the occupants of and the visitors to the BAPD.