U.S. Geological Survey

OVERVIEW OF PRMS MODEL OF MERCED RIVER

Very briefly, the watershed model of the Merced River is based on code from

Leavesley, G.H., Litchy, R.W., Troutman, M.M., and Saindon, L.G., 1983, Precipitation-runoff modeling system--User's manual: U.S. Geological Survey Water-Resources Investigations Report 83-4238, 207 pp.

and represents the daily progress of hydrologic and energy balances

at each of 64 land subunits of the Merced basin above Happy Isles. Together these land units comprise the entire 116,000 acres of the basin, and each "hydrologic response unit" (indicated by the distinct colors in the map below)

was designed--by intersection of topographic, geologic, and vegetational data on a 100-m grid--to contain a narrow range of land hydrologic-response properties. At present, we have sufficient inputs and observations to make runs of daily watershed responses of streamflow, water-budget components, and energy-budget components from water year 1916 to present.