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The Oso Tunnel, with a capacity of 550 cfs, carries the water 5.05 miles from the Little <br />Navajo River to the Navajo River. The Oso Siphon carries the water under the channel of the <br />Navajo River and into the Azotea Tunnel. Additional water from the Navajo River is diverted <br />at the Oso Diversion Dam (WDID 774635) and is added to the flow through the Azotea <br />Tunnel. The Azotea Tunnel, with a capacity of 950 cfs, carries the water 12.8 miles from the <br />Navajo River to Azotea Creek in the Rio Grande basin. <br />The cumulative diversions at the three diversion dams represent an export from the San Juan <br />River basin. There are no return flows to the San Juan River drainage. Records of the <br />monthly diversions at the three diversion structures were obtained from the USBR for water <br />years 1971 through 2002. The average annual diversions for this 32-year period are shown <br />below: <br />Average Annual Diversions (1971-2002) <br />Name WDID Average Annual Diversion <br />(acre-feet) <br />Rio Blanco 294667 35,390 <br />Little Navajo 774636 3,820 <br />Navaj o River 77463 5 41,470 <br />Total 80,680 <br />The authorizing legislation for the San Juan Chama Project places additional limitations on <br />the diversions from the Colorado (San Juan) River basin. Diversions cannot exceed <br />1,350,000 acre-feet in any period of ten consecutive years and cannot exceed 270,000 acre- <br />feet in any one year. Diversions by the Project are also subject to minimum bypass <br />requirements at each of the diversion structures. These bypass requirements (cfs) are set forth <br />below. <br />San Juan Chama Bypass Requirements (cfs) <br />Month Rio Blanco Little Navajo Navaj o <br />January 15 4 3 0 <br />February 15 4 34 <br />March 20 4 3 7 <br />April 20 4 37 <br />May 40 27 88 <br />June 20 27 55 <br />July 20 27 5 5 <br />August 20 27 55 <br />September 20 4 55 <br />October 20 4 37 <br />November 20 4 37 <br />December 15 4 37 <br />On the Rio Blanco, these bypass requirements are similar to the instream flow water rights <br />held by the CWCB. The CWCB rights are for 29 cfs from May 1 through September 30 and <br />20 cfs for the remainder of the year. On the Navajo River, the bypass requirements are also <br />San Juan & Dolores River Basin Information 2-2 <br />