Document Type


Publication Date

January 1970


As demands upon available water supplies increase, there is an accompanying increase in the need to assess downstream consequences resulting from changes at specific locations within a hydrologic system. The problem is approached in this study by hybrid computer simulation of the hydrologic system. Modeling concepts are based upon the development of basic relationships which describe the various hydrologic processes. Within a system these relationships are linked by the continuity-of-mass priciple which requires a hydrologic balance at all points. Spatial resolution is achieved by considering the modeled areas as a series of subbasins. The time increment adopted for the model is one month, so taht time varying quantities are expressed in terms of mean monthly values. The model is general in nature and in applied to a partifular hydrologic system through a programmed verification procedure whereby model coefficients are evaluated for the particular system. In this study the model was synthesized on a hybrid computer and applied to the Bear River basin of western Wyoming, southern Idaho, and northern Utah. Comparisons between observed and comptued outflow hydrographs for each subbasin are shown. The utility of the model for predicting the effects of various possible water resources management alternatives is demonstrated for the number 1, or Evanston subbasin. The hybrid computer is very efficient for model development, and the verified model can be readily programmed on the all-digital computer.