Task 5. Scenarios for NFM in each catchment
The NFM deployment scenarios used in modelling (Task 4) are set within this task and cover: (a) the theoretical maximum extent of interventions and hence maximum possible flood mitigation benefit; (b) a range of scenarios where optimal placement of NFM features is investigated; and (c) a range of 'realistic' scenarios defined by our partners with their local (or wider expertise) in NFM deployment possibilities. This third set of scenarios comes from a range of partner and wider stakeholder activities undertaken in Task 7.
Specific tasks:
The magnitude and variability of hydrological variables (e.g., evaporation, overland flow, soil moisture content) vary considerably between different topographic locations in catchments (e.g., Western et al., 1999). As a consequence, NFM changes to hydrological flows and stores may differ systematically between these locations. In Task 5.1, the Q-NFM investigators will identify a series of academic scenarios to isolate specific landscape features or attributes to map. These scenarios will include contrasting effectiveness of specific NFM measures between, for example, hilltops, steep slopes and valley bottoms; headwater areas and downstream lowlands; areas of slowly permeable versus well drained soils; areas of unconfined vs confined groundwater aquifers. The maps ('NFM Extent Map Set 1') will be developed within JBA's spatial mapping platform. This platform is used to deliver NFM Opportunity Maps for the Environment Agency and allows us to draw upon the acknowledged expertise of subcontractor, JBA Consulting. We use the same GIS platform to develop the maps for Task 5.2 and Task 5.3 ('NFM Extent Map Sets 2 and 3'). The scenarios for the Task 5.3 maps are shaped by a range of differing environmental, social and economic needs and necessarily co-developed with our project partners (and wider stakeholders) in a series of workshops under Task 7.1. The three separate tasks will deliver a library of three separate sets of NFM Extent Maps for each large catchment for subsequent modelling in Task 4. Because we run the NFM scenario sets twice during the course of the project, the partners will have the opportunity change the partner-defined maps (Task 5.3) prior to the second iteration.