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• recorder located in the channel upstream of the splitte box. Coupled with the continuous stage <br />record, measurement of instantaneous discharge over time will yield a stage versus discharge <br />rating curveforSW-N104. Discharge measurements indicated thatirrigationflowvariedfromahigh <br />of 27.6 cfs (August, 1986) to a low of 14.9 cfs (August, 1987). Flow occasionally receded to a trickle <br />during the irrigation season, when water in the ditch was temporarily turned off due to routine <br />maintenance or unforeseen problems up-stream in the main ditch. <br />Surface water Site SW-N105 is located on the West Lateral at about the midway point between <br />Sites SW-N104 and SW-N106. Instantaneous discharge measurements were conducted aY this <br />site in a wooden splitte box. Measured flow values are summarized for each month and are <br />included with stream gaging flow reports presented in Peabody Appendix 7-5. Measured discharge <br />ranged from 9.2 cfs (August, 1987) up to 14.7 cfs (May, 1987). <br />Surface water Site SW-N 106 was the most-downstream monitoring site located on the West Lateral <br />irrigation ditch. AsatSW-N104,instantaneousdischargemeasurementsweremadeatSW-N106 <br />in the diversion splitte box, and continuous flow monitoring was conducted atthis sitewith a stilling <br />• well and recorderalso located in the channel upstream ofthe splitte box. Astage-discharge curve <br />will be more defined overtime at this site, as more measurements of instantaneous discharge are <br />obtained and correlated with the continuously recorded stage measurements. Measurements of <br />instantaneous discharge indicated that the ditch delivers irrigation water to the location of SW-N 106 <br />for a range of from 7.0 cfs (August, 1987) up to 12.4 cfs (May, 1987). Measured instantaneous <br />discharge values can be found in Peabody Appendix 7-5. The ditch flow recedes almost to zero <br />during periods of ditch maintenance. <br />A "gain-loss" study was performed on the West Lateral irrigation ditch on July 7 of 1986. <br />Measurements of instantaneous discharge were collected along the ditch course atselect diversion <br />locations just upstream of each diversion of irrigation water. Measurements were made using a <br />Marsh-McBirneyflowmeterforobtaining velocity readings, and a tape measurefordeterminingthe <br />cross sectional area of the channel at each measurement location. <br />Sixty two percent of the ditch water was either diverted or lost (due to evapotranspiration and <br />seepage) from the West Lateral splitte flume to Site SW-N106. The greatest percentage of lost flow <br />• (30 percent) occurred in the reach between the "Benson's Corner" box (13) and SW-N105 (14). <br />(Revised 6/28/01) 2.04.7-30 <br />