Twin Cities WRS Seminar
Modeling Hydrology and Climate Scenarios in a Northern Minnesota Boreal, Headwater Catchment Using HSPF
A large fraction of the runoff generated in watersheds and river basins originates in headwater areas of watersheds, and much of the biogeochemistry of watersheds is associated with processes in headwater areas. It is therefore important that the hydrology of headwater watersheds needs to be understood well. In recent discussions among hydrologists in the national and international community it is clear that headwater watersheds pose special challenges to hydrologic modelers because of the usual ephemeral character of flows generated in the headwater areas. In the present study we applied the HSPF model to a 9-ha watershed located in the Marcell Experimental Forest north of Grand Rapids. The model of the watershed was conceptualized as being composed of two subareas, the upland and the bog area of the watershed. The model was calibrated with a flow record for the period from 1990 – 1995, and validated with a flow record for the period from 1996 – 2000. NSE values for the calibration and validation were both greater than 0.80. Interesting features of threshold runoff generation in the watershed were identified in the outflow data and corresponding bog water levels. The calibrated model was applied to assess the resilience of the watershed hydrologic response to projected climate change in the region. The most conservative and most extreme climate scenarios were applied to the model for years 2030-2050 and 2070-2100.