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U J I) ;H WATER AVAILABILITY . It is difficult to summarize the availability of water because situations vary so widely throughout the basin. Basically, in asse~bling hydrologic information, over 500 gaging stations that had records of over 10 years were analyzed. To give some idea of the variability of runoff the preceding ~hart shows the recorded annual runoff at Hermann, Missouri, which is the most downstream gaging station in the Missouri Basin. It will be noted from the ~hart the median water supply for the period of record is nearly 60 million acre-feet. The flood years of 1915, 1927, 1940's, 1951, and 1952 naturally show the highest runoff. Also of significance are the droughts of the 1930's and that of the mid- 1950's, though during this latter period many of the reservoirs on the main stem and the tributaries were being initially filled, which reduced flows during this period. Water use has been developing since the mid-1800's and the rate at which development has been progressing has increased rather rapidly in the recent years. Thus, a record of streamflow as is shown at Hermann does not correctly show the availability of water because of the depleting effect of further development with' time. Thus, only the most recent records indicate the full depletions. Recognizing this, estimates of the growth of the depletions were made and historic flo~ls adjusted. The following chart indicates the current level of depletions of about 13 million acre-feet. GROWTH OF STREAM FLOW DEPLETIONS IN THE MISSOURI RIVER BASIN w ~ ~ w, ~ / T / 17 V i-- / / / V V " ~ w" w ~ w <r u <" z o J -,,, ~ , "' z 0, ~ w -' 0- w o. -' < :> z z < , o 1860 7D 80 90 11100 10 20 30 40 50 60 1117D TIME IN YEARS 15