Laserfiche WebLink
<br />the system excitations. The control variables are the diversions :from the streams or <br />reservoirs and pumping from farm and city wells. These excitations are needed as inputs by <br />the physical model. The amount of surface water to be diverted :from the streams depends <br />upon the water right priority, the amount of water physically available in the stream, the <br />irrigation water requirement at the farms and/or other controls imposed by the management <br />strategy . <br /> <br />2. The ohysical model, using the results of the allocation model, predicts the new state of <br />the basin based on physical laws that govern the movement of the water both above and <br />below the ground surface. The physical system may be divided conceptually into four basic <br />components: (1) the surface water system (rivers, reservoirs, diversion canals, surface, <br />reservoir spill canals to the river, and artificial recharge of the aquifer), (2) the root zone, (3) <br />the unsaturated zone :from the root zone lower boundary to the groundwater level, and (4) the <br />saturated zone of the aquifer (Morel-Seytoux and Restrepo, 1987). Most of these processes <br />are modeled on a daily basis. The aquifer system however, is modeled on a weekly time <br />scale because groundwater flow is much slower than that of surface water. <br /> <br />5.0 Simulation and calibration <br /> <br />The model was formulated, and a calibration was attempted for the South Platte River basin :from <br />Denver to the Nebraska state line. Two options are available when running SAMSON (Morel- <br />S_eyt.oux~(g.!<s_tr~P.Q, 12~.7.L_ n_ ___ _ _ _ _ _ _ <br /> <br />1. Calibration which uses historical and operational data. The user can adjust different <br />parameters in order to obtain a good match between observed and historical values. The <br />calibration period should include both extreme high and extreme low events. The calibration <br />was completed by a trial-and-error procedure on a five-year period, starting on January 1, <br />1968. <br /> <br />2. Simulation which needs only inflows to the study area and climatological data for the <br />current calculation day. The user can try different allocation strategies, climatological <br />conditions, and physical parameters. Thus, it is possible to compare different output results <br />for water management studies. <br /> <br />6.0 Data requirements <br /> <br />The initial tasks required of a potential user of the SAMSON model are to clearly define (Morel- <br />Seytoux and Restrepo, 1987): <br /> <br />. the region which is to be simulated, defining the edges of the aquifer system using <br />information about the hydrogeologic characteristics <br /> <br />. the river system, including the location of the river ga"aing stations <br /> <br />. the layout of the main distribution canals of the supply areas <br /> <br />0645 <br /> <br />9 <br />