WSP06217

• File Number: 8510.100.60
• Description: Rio Grande Compact Commission
• State: CO
• Basin: Rio Grande
• Date: 3/18/1999
• Author: USDOI/BOR
• Title: 1998 Report to the Rio Grande Compact Commission
• Water Supply Pro - Doc Type: Publication

199B report to the Rio Grande Compact Commission

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Bureau of ReClamation

channel for the new channel system. A 310-foot riprap low water crossing was also
constructed across the old channel to direct flows into the new channel system. The
pilot channel length was approximately 4,600 feet.

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Approximately 5 miles of the San Marcial Levee was raised to accommodate increased
water surface elevations in the river reach due to channel aggradation. The levee is
designed to pass 8,000 cfs with 2 feet of freeboard. Approximately 138,000 cubic yards
of material was hauled from the Valverde Pit and placed.

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Endangered Species

Rio Grande Silvery Minnow

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The U.S. Fish and Wildlife Service (Service) listed the Rio Grande silvery minnow
(silvery minnow) as endangered in 1994. The silvery minnow is currently found in about
170 miles of the Rio Grande in central New Mexico, from Cochiti Dam to the
headwaters of Elephant Butte Reservoir. This reach of the river, commonly referred to
as the middle Rio Grande, comprises less than 1 O-percent of the silvery minnow's
historic range. Critical habitat designation was proposed from the State Highway 22
bridge below Cochiti Dam downstream to the railroad bridge crossing near San Marcial,
New Mexico.

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, During 1998, Reclamation continued to secure and jointly manage supplemental water
, in conjunctiori with MRGCD's native water to minimize adverse effects of river recession
; on the silvery minnow. Reclamation obtained about 54,000 af of SJ-C water from the
City of Albuquerque and other SJ-C contractors. This volume was insufficient to
maintain continuous flowing water to San Marcial through the end of October. The
lower reach of the middle Rio Grande (immediately above Elephant Butte Reservoir)
receded twice; in late June and early September. Reclamation cooperated with the
Service to physically relocate fish in September. Throughout the year, water operations
were constantly evaluated for short- and long-term opportunities to maximize available
water supplies.

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Management of supplemental water benefitted the silvery minnow by reducing the
extent of channel drying that would have otherwise occurred and thereby increasing the
survival of silvery minnow through the driest periods of summer. No silvery minnow
population monitoring occurred during 1998 due to delays in the issuance of federal
collecting permits. Prior to 1998, silvery minnow populations were still recovering from
drought conditions in 1995-96. Early 1999 monitoring will be used to indirectly assess
the response of silvery minnow to 1998 water operations. Reclamation continues to
take a pro-active approach to Rio Grande aquatic issues, especially those relating to
the silvery minnow, by developing and funding aquatic research and monitoring
programs, securing and overseeing the management of supplemental water, and
incorporating river restoration into its' river maintenance program.

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Also in 1998, environmental groups formed a coalition named the "Alliance for the Rio
Grande Heritage" and issued a "green paper" that set forth specific recommendations

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