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<br />"':t' <br />t~ <br />00 <br />C'J <br /> <br />1935 - Warm spring f0llo~nng dry year in 1934 caused early start of <br />irrigation, with high diversions in spite of excess rainfall in <br />April and May. Rot dry surnoer with low flow "tnd return water. <br />Most of water hae been used by end of June. <br /> <br />1936 - Dry and hot all season with low floOG. Lower ditches diverted <br />more water propartienally than upper ones, indicating same restora- <br />tion of return flow since dry year of 1934. Summer flow so low <br />project ditches got very little after July 1. <br /> <br />From Table 3 and Plate 2, certain general tendencies are clear: <br /> <br />(a) Junior appropriators start irrigating as early as we,ter is avail- <br />able in spite of unsuitable weather; netably the Divide Creek <br />Righline started April 10, 1932, after the dry year 1931 although <br />it serves land above 6,500 feet elevatien; in 1934, known in <br />advance to be a dry yeqr, the Multi Trina ditch started diver- <br />sion February 15; in 1935, the Porter ditch exercised its prior <br />right to start iITigating April 1, apparently :lS soon a s flood <br />water was ~vailable. <br /> <br />(b) Until the end of the flood, ditch capacity, not decreed right, <br />is the ~asure of diversion, and all rights divert at a rate in <br />excess of one acre-foot per acre per month, the junior rights <br />more tlli~n the senior if pOSSible. <br /> <br />(c) When stream flow falls below the amnunt of current civersions, <br />the Divide Creek Righline and Port3r ditches are reduced rapidly <br />oecause they depend cn stream flow. When return flow is avail- <br />able (except in and following very dry years) the West Divide and <br />Multi Trina ditches continue to divert at greater rates propor- <br />tionally. (See Plate 2) <br /> <br />(a) Return flow is a function not only af current runoff, but of <br />grcundwater cnnditions inherited frcm previous years. The <br />Multi Trine ditch has not diverted its average in any year <br />since 1931, and the lowest diversions were in 1932 and 1933. <br />The West Divite ditch has some old rights, but is principally <br />dependent m return flow and did not reach its average in 1933 <br />or 1935, although the return flow seems to have somewhat re- <br />covered in 1936. <br /> <br />Senior rights not shown in the table have much more water <br /> <br />in late summer. They seldom divert vmter in April and usually do <br /> <br />not start diversion as early as the project ditches, in spite of whicn <br /> <br />31 <br />