The influence of land management and seasonal changes in surface vegetation on flood mitigation in two <scp>UK</scp> upland catchments

As the frequency and magnitude of storm events increase with climate change, understanding how season management influence flood peaks is essential. The grasslands on peak timing was modelled for Swindale Calderdale, two catchments in northern England. Spatially-Distributed TOPMODEL used to investigate scenarios across four using empirically-based soil vegetation data. first scenario applied seasonal changes vegetative roughness, quantifying effect at catchment scale. second grassland from historical high-intensity grazing a series natural succession stages between woodland, conservation-based management. Model outputs were analysed by flow type, measuring total, overland base outlet. Seasonal found up +2.2% winter reduce them −5.5% summer compared annual average. Percentage due hillslope more substantial; reduced 41% Calderdale where extensive woodland development most effective mitigation strategy, 35% Swindale, rank dominated effective. Conservation-based farming practices also useful, reducing 42% high intensity scenario. Neither nor seasonality changed runoff >45 min. Where dominates, especially shallow soils, surface roughness be influential than permeability mitigation. We recommend that are considered alongside spatial distribution Natural Flood Management mosaiced upland catchments.