Predicting the hydrologic and water quality implications of climate and land use change in forested catchments Dennis P. Lettenmaier Department of Civil and Environmental Engineering University of Washington Joint UW/Cimate Impacts Group – NW Fisheries Science Center Meeting June 12, 2003 Seattle
VIC Simulations of April 1 Average Snow Cover Extent MPI ECHAM4 Scenarios ~2025 ~2045 Base Case
Changes to Mean Hydrographs Columbia Basin 2045
ColSim Reliability of System Objectives
DHSVM basics Physically based hydrologic model Grid based (DEM) Two layer canopy for vegetation Simultaneously solves energy and water balance
DHSVM Input and Output DEM Met. data Vegetation (type, LAI, height, etc.) Soil texture Soil depth Critical shear stress DHSVM Critical soil moisture Soil moisture Overland flow Channel flow
Mass Wasting Module Multiple realizations of total failure locations Multiple time series of sediment supply Soil depth DEM Soil info Vegetation info P(F) MASS WASTING
Surface Erosion Module Soil Precipitation Vegetation DEM Multiple time series of sediment supply Overland flow SURFACE EROSION Distribution of sediment delivery to channels (roads and streams) Roads and streams
Channel Erosion Module Channel flow CHANNEL EROSION Mean and standard deviation of sediment load for selected channel reaches Distribution of sediment delivery to channels (roads and streams)
Watershed Sediment Module validation suggestions Mass wasting Regional land slide frequency and extent over a multiyear period derived from ground-based mapping, remote sensing or aerial photography Surface erosion Compilation of regional observations of land surface and road surface erosion rates Channel routing Observed stream discharge and sediment concentrations over a multiyear period
Probability of slope failure before and after Fourth of July Fire Pre-fire Approximate extent of August 2001 fire Post-fire Icicle Creek Vegetation