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<br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br /> <br />V-7 <br /> <br />ditch banks has been intermittent over the years. As a re- <br />sult, the carrying capacity varies by canal segments and is <br />primarily influenced by the gradient, There is an abundance <br />of vegetation along the ditch banks, including willows, <br />cottonwood trees, juniper trees, grasses and weeds, As in- <br />dicated in Chapter IV, the ditch loses large amounts of <br />water to the riparian vegetation and to the fractured lime- <br />stone in the ditch bottom, <br />The original ditch had several flumes to carry the water <br />over small gullies and streams. These .flumes deteriorated <br />with time and were replaced by extending the ditch around the <br />original flume section, This action resulted in an increase <br />in canal length and a consequent reduction of gradient in <br />those segments, At present, the ditch is carried over only <br />two gullies in culverts, at stations 39 and 85. These by- <br />pass segments are generally in rocky terrain and have con- <br />siderable evidence of seepage losses, including visible <br />seepage below the ditch banks, <br />The flat gradient of the canal when combined with the <br />low ditch banks results in several areas of overflow when <br />the diversion rate exceeds 40 cfs. The worst overflow occurs <br />at station 110. <br />The lateral gates are all antiquated and have consider- <br />able leaks when shut off, The gates are cast-iron or fabri- <br />cated steel plates. Some are equipped with hand wheels and <br />screw-thread stems, others must be wired into an open position. <br />There are no measuring devices at any of the lateral gates, <br />This lack of measurement means that the ditch rider must <br />estimate the flow into the lateral and then make several <br />round trips to the delivery points to adjust to the necessary <br />flow rate, <br />The Penrose Water District delivery point is located at <br />station 95 on the canal. Because of the necessity to supply <br />the water system on a year-round basis, the canal must always <br />carry water to that point, At times during the irrigation <br />season when the diversion ~ate falls to less than 6 cfs, <br />about half of that flow is lost to seepage in order to supply <br />