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e HISTORIC DIVERSIONS I Intake Canal River Diversions Mode -- The Model Intake Canal diversions from the Purgatoire River are red by a ten foot Parshall flume located approximately 1,200 feet measu below the headgate facilities at the Purgatoire River. Much of the flow in the canal at the Parshall flume is diverted into the Johns Flood Ditch at a point approximately 2.3 miles below the flume. The diversions into the Johns Flood Ditch are then measured separately. The Model Ditch diversions, as recorded by the water commissioner, are the Model Intake Canal flume measurement less the Johns Flood Ditch flow measure- ment. e In order to obtain an extensive period of water diversions by the Model Ditch, the water cornmissionerls daily diversion records were summa- rized on a monthly basis for the period of 1950 through 1976 as shown in Table V. Average annual diversions amounted to 7t627 acre-feet with a maximum of 28t963 acre-feet in 1961 and a minimum of 625 acre-feet in 1975. The Model Intake Di tch diverted less than the average amount for 17 out of 27 years. As expected the Model In~ke Canal river diversions vary drastically from month to month and year to year because of legal limitations. The 1908 decree for the Model Ditch is very junior and diversions were only permitted during times of high river flows and during the winter non-irrigation season. Model System Intercepted Runoff e As stated previously the Model Intake Canal, Model Reservoir, and Model Ditch intercept runoff from several arroyas. This water was not measured and therefore it was necessary to estimate the quantity of intercepted runoff. This was done by examining precipitation records and runoff indicated by the Frijole Creek stream gaging station. Since precipitation events (thundarstorms) are frequently quite localized it was also necessary to exercise judgment by comparing the predicted runoff 12 --