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39 COMMEN'rS BY DALE B. RAITT MW purpOse, as was just stated by Mr. Greer, iS,to indicate the conclusions drawn from our studies. Before discussing nw main subject, however, I would like to make several observations.! ' If the efficiency of water utilization in the basin could be increased, ouky a little, it would make far more difference to basin water sUpplies than the location of the site. Our studies show that it takes a little more than five acre-feet per acre at the river to deliver a full water supply at the crop. This figure is derived under the criteria that historic diversions and existing efficiencies remain unchanged; and only if shortages ,remain, can additional water be routed to them under higher efficiencies. It appears that a significant part of these diversions are made because of water availability rather than need. In the ,future when there is a more assured water supply the efficiency of use will increase. Lf we assume that in the future there could be attained a 60 percent farm efficiency, , we would need a farm delivery of 2.25 acre-feet per acre to obtain a full supply at the crop. This figure and the breakdown by reach is shown on line 5 under General Hydrology on Table 1. Immediately below that on line 6 is the calculated river diversion requirement in, acre-feet per acre assuming that the canal efficiency could be raised only to 60 percent. The river diversion require- ment, assuming this efficiency, would be reduced from the five acre-feet per acre; which we used, to less than 4 acre-feet per acre) a more than 20 percent savings of your water supply. Another observation should be drawn between our computed river diversion shortages and the ditch company estimates of additional water requirements as shown on lines 4 and 5 of Table 1 under the section on Historic Rydrologic Conditions. You will note that our estimate for ditches in the Denver to Weld County area are considerably greater than those of the ditch companies. The two estimates of the water needs in the Weld County to Narrows area are not tOo far apart) 49,000 acre-feet against 35,000 acre- feet. In the lower area our estimates are less than those of the ditch cOll1panies'. There are too many factors, too numerous to mention at this time, which enter into these esti~ates and could cause these differences. Regardless of this, and more importantly, no matter which Shortage estimate is used, there remains more demand for water than there is supply in each of the three reaches.