You are here:
A SIMPLE HYDROLOGICAL MODEL FOR WATERSHED CHARACTERIZATION
Citation:
PAN, F., M. STIEGLITZ, AND R. B. MCKANE. A SIMPLE HYDROLOGICAL MODEL FOR WATERSHED CHARACTERIZATION. Presented at American Geophysical Union Fall Meeting, San Francisco, CA, December 11 - 15, 2006.
Description:
Catchment behavior is characterized with a variety of metrics - discharge, chemical export, biological activity, to name a few. Catchments have complex temporal behavior, e.g., summer and winter storm recessions and nutrient export may look nothing alike. Further, catchment response is dictated by spatial scale. Given these difficulties, we sought to identify the simplest possible model structure that provides a parsimonious description of experimental and observational evidence on how changing geomorphologies, climatic zones, etc., dictate the seasonal and inter-annual variability in catchment response. We developed a spatially-explicit hydrologic model in which catchments are partitioned into connected landscape cells. Each cell is connected according to the flow directions. We validated modeled discharge at the WS10 catchment of the HJ Andrews LTER, Oregon, and the Kings Creek catchment of the Konza LTER, Kansas. Given a suite of climatic regimes and geomorphologies, we then used this model to study catchment behavior, specifically, low frequency behavior. Two indices are adopted to characterize the low frequency response of catchments: 1) the lag time between precipitation and discharge peaks, and 2) the spectral power of precipitation divided by the spectral power of discharge. Indices for 100 idealized geomorphologies under 50 distinct climatic regimes were computed based on 5000 numerical tests. The indices were then used to construct a regime diagram of catchment response to different climatic regimes and geomorphologies.