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<br />",~ <br />.......~.-: <br />'::1. <br /> <br /> <br />:] <br /> <br />oozc,JiJ <br />1996 Report to the Rio Grande Compact Commission <br /> <br />Bureau of Reclamation <br /> <br />.......) <br />'.-', <br />:>~ <br />,:"J <br /> <br />SAN JUAN.CHAMA PROJECT, COLORADO.NEW MEXICO <br /> <br />"-"l <br />I <br />\ <br />;'3 <br /> <br />San Juan-Chama Diversion Dams <br /> <br />During the winter of 1996, Chama Field Division personnel postponed some of the <br />maintenance on the tunnels due to a deficient runoff and the corresponding need to <br />divert as much San Juan-Chama Project water as was available by extending the <br />diversion period, No tunnel invert concrete repair work was performed in 1996. <br />However, repairs were completed for the Little Oso and Oso Siphons in March. During <br />the fall, riprap was placed at two box culvert crossings along Willow Creek, and <br />erosion control riprap was placed on the dike at Heron. Diversions began on March 21 <br />and continued through December 3. Atotal of 58,530 af was diverted through Azotea <br />Tunnel during 1996 (see Table 2), <br /> <br />Heron Dam and Reservoir Operation <br /> <br />The poor snowpack and resulting low runoff volume in.1 996 resulted in one of the <br />lowest total diversion volumes on record. As a result, 1996 was the first year that <br />Heron did not fill since the early 1980's, To compensate, the diversion period was <br />extended into December. In most years since 1980, diversions have ceased during the <br />fall, and maintenance of the diversion system has begun. Heron began the year at its <br />highest elevation of 7,185.85 feet (ft) (376,681 af). The reservoir continued to <br />decline and ended the year at its lowest elevation of 7,168.67 ft (305,916 af). <br />Reclamation remains prepared to take water to start the 1997 season. <br /> <br />v...' <br /> <br />Reclamation again was offered waivers, by the San. Juan-Chama contractors; <br />extending the required delivery date of December 31, 1995 to April 30, 1996. This <br />extension provided an opportunity to stabilize the flows below EI Vado Dam to provide <br />fishery benefits and allow for additional operational flexibility. Reclamation is <br />transitioning away from utilizing annual waivers and plans to deliver all 1997 San <br />Juan-Chama Project water by December 31, 1997. A summary of San Juan-Chama <br />Project water releases from Heron Reservoir, monthly reservoir inflow and storage <br />computations, and San Juan-Chama water delivered to the Otowi river gage index <br />station during 1996 are shown in Tables 3, 4, and 5. <br /> <br />9 <br />