Quantifying the effects of watershed subdivision scale and spatial density of weather inputs on hydrological simulations in a Norwegian Arctic watershed

Abstract The effects of watershed subdivisions on hydrological simulations have not been evaluated in Arctic conditions yet. This study applied the Soil and Water Assessment Tool threshold drainage area (TDA) technique to evaluate impacts subdivision at a 5,913-km2 watershed, Målselv. was discretized according four TDA scheme scales including 200, 2,000, 5,000, 10,000 ha. different schemes water balance components, snowmelt runoff, streamflow were investigated. revealed that complexity terrain topographic attributes altered significantly coarse discretizations: (1) total stream length (−47.2 −74.6%); (2) average slope (−68 −83%); (3) density (−24.2 −51.5%). spatial weather grid integration reduced from −5 −33.33% schemes. annual mean potential evapotranspiration, lateral flow slightly decreased, while areal rainfall, surface yield increased with increases TDAs. It concluded fine TDAs produced finer higher ranges runoff volume across watershed. All had similar capacities replicate observed tendency monthly hydrograph, except overestimated/underestimated peak flows. Spatial variation well analyzed high networks, simplified this. Watershed affected model performances, way decreasing accuracy simulation, 60% investigated hydro-gauging stations (3/5 stations) upstream. Furthermore, strongly calibration process regarding changes sensitivity ranking 18 calibrated parameters time it took calibrate.