Animas- La Plata Environmental Impact Statement

3 0 project New Mexico municipal and industrial demand
the a minimum bypass to maintain the aquatic ecosystem
capacity of the Durango Pumping Plant
amount of water in Ridges Basin Reservoir
e The proposed Durango Pumping Plant would have a total pumping capacity of 280 cubic feet per second
-- -(cfs) (varying from approximately 5 cfs to 280 cfs). Several various size pumps would be used to obtain
this total capacity. The specified capacity is in addition to the City of Durango pumping plant with a
capacity of 11 cfs which may be combined into the Ridges Basin Pumping Plant upon construction. The
model accounts for the full pumped volume of the two plants. ,
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Pumping would only occur after all downstream senior water rights demands and downstream Project
water demands have been satisfied. Downstream Project demands in the Animas River are met first by
streamflow available after meeting historic demands, including ALP Project return flows entering above
the diversion point, and then by release from Ridges Basin Reservoir.
After satisfying all downstream senior water rights demands and downstream ALP Project water
demands, pumping may be further limited to allow the following bypass flows in the Animas River at
the pumping Plant intake: October through November -160 cfs: December through March -125 cfs: and
April through September - 225 cfs. Pumping would also be decreased or stopped during certain periods
in order to meet the recommended flow requirements in the San Juan River for the Endangered Fish
Recovery Program. When there have been no endangered fish releases from Navajo Dam for two yews
and the planned release for the current year is the miaimugt respiod in the flow recommendation
report, the Durango Pumping Plant is turned off during June, allowing an additional 280 cfs to meet flow
recommendations for endangered fish in the San Juan River. -
As stated in Section 3.2.4 of the FSEIS, the amount of water diverted from the Animas River is greatest
during the wet periods, however, impacts are not great during this time because the diverted amount is
only a small percentage of the total flow. Impacts are limited in the upper Animas River during low flow
times because of the minimum flow bypass requirement and demands downstream preventing any
pumping from taking place. In the lower river, the impacts is greatest in moderately dry months when the
project diversions reduce the flows past the last diversion. In the driest months there is no significant
change in flows in the lower river area. Releases from Ridges Basin Reservoir during these dry months
supply the project demands with no significant change to the flows in the river below the last diversion
,r point. Project releases to meet downstream project demands are protected by both Colorado and New
Mexico State Water Law as project water.
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Tables 3.2-4 in the FSEIS provides historical flows and projected flows information for three locations
on the Animas River, with the ALP Project in operation. In addition, revisions have been made to
Volume 2, Attachment F for the FSEIS.
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