WSP09036 - Laserfiche WebLink

Home Browse Search

. .,.~ ':;"1.';.) 22 METROPOLITAN WATEn D1S1'II1CT resulting J'llIlofl' overtopped a protective embanl{ment and Huoded the plant area at Eagle Mountain. Road dips were filled with sand and ]'ock, and overflow from clogged culverts \\'w..hed acros:-\ patrol raa-dio;. Con:-;iderable debri:;. including soil and gravel, was washed into Eagle Mountain resen'oir antl into the inlet channel leading tu lhe pumps. After the debris was cleaned from the reservoir and inlet channel and roads were repaired, a new dip was constructed on the Eagle Mountain road at the northeast corner of the reservoir and a drain ditch was built north of Eagle Mountain to carry storm water around the pumping plant and across the cut-and-cover con- duit section. Each winter the low temperature of the fiowing water in the aqueduct causes contl'action of the concrete thus opening cracks in the shell of circular siphons and causing leakage at several locations. Prior to November 1847 it was not necessary to pump water during most of the cold months, but since that time aqueduct operation has been practically continuous because of the steady demand of 90 to 100 cubic feet per second by the San Diego County Water Authority. During the winters of 1847.48 and 1948-48 with low water tempera- ture~ of 380 and 350 respectively, leakage was the ma~t severe since the beginning of operation from siphons at mile 18.30, Freda, Pinto, West Wide, and Lakeview, ,md at the joint between Eagle Mountain surge chamber and the adjoining siphon. Leakage was more than :300 gallons per minute at both Freda and Lakeview siphons. Cracks were repaired as well as possible from the outside of the barrels. During the winter of 1949-50 the leakage was considerably reduced, the maximum being 32 gallons per minute at Freda. Last winter there was only minor seepage at the critical siphons, a maximum of 5 gallons per minute being estimated at Lakeview in February 1951- This small amount of leakage was attributed to a relatively high minimum water temperature of 460, the lack of periods of rapid temperature change, and to the repair work in previous years to seal off cracks. In order to obtain more complete measurements of main aqueduct flow, five additional gaging stations were constructed. Two were in canal sections, one near Rice and one between Iron Mountain and Coxcomb tunnels; and three were in cut-and-cover conduit sections, one between East and West Eagle Mountain tunnels, the second near the west portal of Cottonwood tunnel and the third at Fan Hill. Added to the three former stations which are located at Vidal. near the east portal of San Jacinto tunnel, and near the east portal of Valverde tunnel, there are now eight gaging stations on the main l I I , I I I I 1