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<br />1056 <br /> <br />as the sum of amounts, during the growing season, by which the maximum daily <br />temperature in degrees Fahrenheit exceeds 32 degrees. The Thornthwaite distri- <br />bution proportions the total gross consumptive use among the months according <br />to each month's fraction of a theoretical total potential consumptive use. <br />This procedure was used by the U. S. Bureau of Reclamation in the Fryingpan- <br />Arkansas Project studies, but it makes no allowances for different crops or <br />climatological data except daily maximum temperatures. <br /> <br />Unfortunately, values computed by this method do not agree well with <br />tentative values computed by the modified Jensen-Raise method. In this method <br />a potential evapotranspiration is computed from solar radiation or percent <br />possible sunshine and temperature data. This is multiplied by the crop coeffi- <br />cient, which is dependent upon the stage of growth of the crop, to yield the <br />consumptive use for that particular crop during the period considered. Thus, <br />the determination of consumptive use by this method involves a series of <br />computations for each crop in the study area. This method was derived from <br />energy budget studies in many areas and is generally believed to give reliable <br />results. The differences in computed consumptive use by these two methods will <br />be investigated in the future to determine which is the most reliable, and a <br />revision will be made if necessary. <br /> <br />In a Colorado State University report, ~ Study of Phreatophyte Growth <br />in the Lower Arkansas Valley of Colorado, by Bittinger and Stringham, an estimate <br />of annual consumptive use by phreatophytes in the reach from Nepesta to La Junta <br />for 1957 is presented. This estimate was reduced to arrive at a figure for use <br />in the Oxford Farmers water budget computations by proportioning on the basis <br />of river miles and dividing by two. It was then proportioned among the months <br />of the irrigation season USing the Thornthwaite distribution as was done for crop <br />consumptive use. It is recognized that phreatophyte concentration has increased <br />since 1957, especially since the 1965 flood, and a better estimate will be avail- <br />able for the final report. <br /> <br />It should be mentioned, although it was not required for the water <br />budget computations, that several drains take water out of the study area. The <br />major one is Hungerford Hollow which drains a large area south and east of Fowler. <br />Two other drainage ditches, Clark Drain and Breden Ditch (commonly known as the <br />Otero Drain), empty into Hungerford Hollow. In July 1968, staff members of the <br />Colorado Water Conservation Board installed a recorder in Hungerford Hollow near <br />its confluence with the Arkansas River and below the mouths of the other drains <br />as shown in Plate 1. Recorded flows have ranged from a low in February 1969, of <br />154 ac-ft to a high in July 1969, of 596 ac-ft. Total irrigation season flows <br />for 1969 and 1970 were 2,712 and 2,616 ac-ft, respectively. <br /> <br />The City of Fowler has two drains: one on the west side commonly known <br />as the Green Drain, and one on the east side commonly known as the city storm <br />sewer. Personnel of the Water Board staff measured the flowrate of these drains <br />with a Sparling flow meter on August 28, 1969, when conditions were normal -hot, <br />dry and after several days with no rainfall. Both drains had a flowrate of about <br />0.4 cfs. <br /> <br />The monthly water budgets for irrigation seasons 1968-1970 are presented <br /> <br />- 16 - <br />