WSP01136

• File Number: 8543
• Description: Closed Basin Division
• State: CO
• Basin: Rio Grande
• Water Division: 3
• Date: 1/1/1979
• Author: DOI/BOR
• Title: Final Environmental Statement - Closed Basin Division - San Luis Valley Project - Alamosa and Saguache Counties CO
• Water Supply Pro - Doc Type: EIS

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natu,al runoff not equal 8,000 acre-feet in a given year,
the deficit would be repaid during yea~ of high runoff.
There would be no use made of runoff down Saguache Creek proper
as this channel would be used as a management feature with
the runoff water entering it going on through the refuge
proper.

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Subsequent to House Document 91-369 (1970) and the authorizing legis-
lation (Public Law 92-514 [1972]), considerable changes have occurred in
project features, such as deletion of channel rectification of 12 miles'
of the Rio Grande, deletion of the annual salvage of 15,200 acre-feet of
surface water, deletion of the east side conveyance channel, deletion of
the connecting channel~etween the conveyance channel and San Luis Lake,
rerouting of the ~onveyance channel through Alamosa NWR, deletion of
conveyance channel collection system to collect surface water outflows
from Mishak Lake (see section C-l), the proposed development of the
San Luis Lakes State Wildlife Area, and the development of the Blanca
Wildlife Habitat Area by the Bureau of Land Management (BLM). Addi-
tional studies have indicated reduced inflows into thepcoject wetland
areas as the result of agricultural irrigation changes (see sections
B-4, B-9 and B-lO). Recent investigations by the FWS as a part of the
National Wetlands Inventory and by Bureau of Reclamation studies of
LANDSAT Data, infrared false color aerial photography and ground studies
indicate the original estimate of 100,000 acres of wetlands may be
reduced to from 26,000 to 47,000 acres of wetland (see sections B-9 and
B-10). Low level infrared aerial photography of the unique wetlands
in Stages 3, 4, and 5 taken in 1979 (a wet year) showed a total of
1,350 surface acres of open water on May 3, 1,740 surface acres of water
on June 3, and 1,650 surface acres of water on June IS, all within the
project area.

The effects of the project on wetlands, vegetation, and wildlife and the
necessary mitigation and/or enhancement cannot be adequately determined
at this time. These effects and mitigation needs cannot be determined
for the entire project until additional aerial photography has been
studied, the pumping system has been placed in operation, the water
table has been lowered, and long-range biological field investigations
have been carried out.

Since the project will be constructed in stages; since each stage will
be monitored and the construction of the following stage is dependent on
data collected from the preceding stage; since the primary wetlands
(about 80 percent) are located in Stages 3, 4, and 5; and since the
wetlands in Stage 1-2 are primarily maintained by artesian well flows,
an ideal opportunity exists to determine the wetland, vegetation, and
wildlife impacts and the needed mitigation and/or enhancement features
as construction progresses through Stage 1-2.

A-3