Laserfiche WebLink
<br />. <br /> <br />. <br /> <br />10 <br /> <br />The SCS report does not identify ponds in its water budget. The USBR <br /> <br /> <br />report ..y have included the evaporation component in its "other consumptive <br /> <br /> <br />use" colapoDent. I do not see where they have included seepage. <br /> <br /> <br />I~ ponds are to be considered, then there is the question of' values to use. <br /> <br /> <br />For the "KRK water budget", it is assumed that there are 1000 acres of ponds <br /> <br />that interact and depend on irri.o;ation diversions. The local SCS District <br /> <br /> <br />Conservationist estimated that there are 1700 acres of ponds in the area. For <br /> <br /> <br />evaporation, it is asaumed that 2 ac. ft. per so. per yr. can be used (USBR uses <br /> <br /> <br />39" for canal evaporation) and for the seepage component, a value of 0.5 ac. ft. <br /> <br /> <br />per ac. per yr. is assumed. <br /> <br />CroD Use <br /> <br />I still have nuestions on the aonropriate values to use for this category. <br /> <br /> <br />The situation is especially com"lex for the "present condition" \';here the <br /> <br /> <br />followin~ factors affect the value to ~e used in the water bud~et. <br /> <br />1. "!ater shorta"'es - I "JaS told that startino: about Au"ust I, deliveries <br /> <br />are usually cut 50%. <br /> <br /> <br />2. Field conditions - ;!any surface systems lack the necessary features to <br /> <br /> <br />uniformly distribute water to the crop. Very little land levelin" <br /> <br /> <br />or grading has been performed in the area. <br /> <br />3. Effective Drecinitation - Normal procedure is to subtract this from <br /> <br /> <br />the crOD consumptive use requirement to obtain the cro" irri~tion <br /> <br /> <br />requirement. Design charts for this area show a 5.09 inch effective <br /> <br /> <br />orecipitation value for alfalfa. However, the farmers told ~e that <br /> <br />they never "'et any rain ~hen it ~ill do any ~ood. <br /> <br /> <br />4. Groundwater extraction - Plants will extact some needed ~ater from a <br /> <br /> <br />high water table. If this water table is caused by irri,~tion, then <br /> <br /> <br />the net effect on the crop irri~tion requirement is unchanged for <br /> <br />the entire system. However, individual fields could be effected. <br /> <br /> <br />5. Wet year vs. dry year - For irrigation design, a dry :,ear crop irrio;ation <br /> <br />requirement is used so that 8 out of 10 years the irri~ation system <br /> <br /> <br />will be able to provide the ODtimum amount of water for the crop grown. <br /> <br /> <br />For the more avera~e year, the system would not be used to canacity and <br /> <br />less '~ater could be applied. Therefore, for the purposes of a salinity <br /> <br /> <br />study, I ~~lieve we should be using the average year condition. if these <br /> <br /> <br />values can be accurately determined. <br /> <br />001511 <br />