Opportunity mapping for nature-based solutions for flood hazard reduction and water quality improvements with the SCIMAP toolkit

Nature-based solutions have the capability to slow and store water during storm events, leading to the attenuation of flood peaks and the capturing of sediments and associated nutrients. These features can also provide important habitats for wildlife and pollinators. However, these features do take land that may be agriculturally productive and require maintenance, both factors mean that they have potentially significant ongoing costs. Therefore, it is important to ensure that they are effective and correctly located within the landscape. For all pressures, the location needs to be in a location where the problems are likely to originate. However, for flood waters, it is important to target locations that are likely to contribute to moving water out of the flood peak and into the receding limb of the hydrograph, rather than moving water from the rising limb into the peak. It is also important not to move water from the peak discharge of one community into the peak discharge of another. Therefore, careful analysis and planning are needed to ensure that the benefits from the nature-based solutions are maximised for all in the catchment.

 

The SCIMAP Toolkit provide an approach to assess the potential source area of flood waters, sediments, nutrients and FIOs and to ensure that the multiple benefits of the nature-based solution are realised. The toolkit uses a reduced complexity approach to map the generational of rapid runoff, the mobilisation of material and connectivity to the receiving waters. The SCIMAP-Flood module then considers the travel times to the impact points within the catchment, such as a community or key infrastructure.  This analysis is undertaken in a time-integrated way such that the potential benefits of a nature-based solution are optimised over a range of storms rather than fitting to the unique dynamics of a past event. The analysis is undertaken at landscape extent with sub-field detail, normally at a ground resolution of 1m with the catchment extent covering 1000s of km².  This presentation shows the application of the SCIMAP approach to the spatial targeting of flood mitigation features and how these locations can co-deliver water quality benefits.