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The original outlet works at the reservoir were modified in 1919 to extend the outlet canal and <br />provide an increased discharge capacity of 500 cfs. The outlet works currently in use consist of <br />three concrete outlets, each 3 feet wide by 4.5 feet tall at the arched top. Two control gates on <br />each outlet regulate the storage releases. <br />Capacity: <br />Total Storage: 34,937 acre-feet <br /> There is no storage restriction on the reservoir. <br />Active Storage: 34,937 acre-feet <br />Dead Storage: A permanent pond, approximately 2,500 acre-feet, is prevented <br /> from reaching the outlet due to a berm in the northern area of the <br /> reservoir. <br />Area/Capacity Data: Two different stage/capacity tables have historically been used (see <br /> Table 1). The Water Commissioner for Division 1 historically <br /> used a table with measurements up to full decreed amount (referred <br /> to herein as the Division of Water Resources (DWR) table). The <br /> date of this survey is unknown, although appears to reflect the <br /> capacity at original construction. The Company utilizes a table <br /> apparently developed in 1948 for operational decisions. The 1948 <br /> stage/capacity table accounts for estimated operational losses, <br /> including reservoir seepage and evaporative losses. Since the table <br /> already accounts for losses, the table does not accurately depict <br /> total storage (W. W. Wheeler and Associates, 2000). Therefore, <br /> end-of--month storage contents for the post-1989 period were <br /> developed by reconciling the two stage/capacity tables to facilitate <br /> modeling the entire effect of Jackson Lake operations on the river <br /> system. The historical records available in HydroBase and <br /> developed for this effort are included in Figure 2. <br />Enlargement History: Jackson Lake Reservoir has never been enlarged. <br />Reservoir Seepage Information: Jackson Lake Reservoir experiences an unknown amount of <br />seepage, although reservoir stage can reportedly drop two hundredths of a foot per day <br />due to evaporation and seepage. <br />Reservoir Storage Measurement: Storage levels in Jackson Lake Reservoir are made using a <br />staff gage. The Company operates the reservoir such that the diversions into storage are <br />measured to a gage height, not a volumetric amount. The Superintendent is responsible <br />for collecting and reporting end-of--month storage amount to the Water Commissioner for <br />Water District 1. <br />Jackson Lake Reservoir System Page 7 of 14 <br />