WSP04850

• File Number: 8541
• Description: San Luis Valley Project
• State: CO
• Basin: Rio Grande
• Water Division: 3
• Date: 2/11/1982
• Title: Draft Supplement to Final Environmental Statement
• Water Supply Pro - Doc Type: EIS

The Bureau intends to use this supplement to the FES to satisfy the exemption
for a Section 404 permit to discharge dredged and fill material into navigable
waters. The Bureau has determined that there will be no significant adverse
impacts to wetlands, benthos, nekton, and plankton.

After the draft supplement has been made available to the public, a public
hearing will be held which will in part provide information on the effect the
project will have on wetlands and flood plains (Executive Orders 11988 and
11990).

II. PROPOSED ACTION

A. General. The project will consist of a system of well fields to be
developed in four stages (Stage 1-2 is a combined stage) over a 10-year period.
The well field laterals will collect and deliver the pumped ground water to an
open conveyance channel about 42 miles long. About 100 miles of laterals,
140 miles of electric transmission lines, and 13 million kilowatt-hours annually
of electricity will be required.

B. Chan~es in the project plan. The proposed action is the same as that
presented in the 1979 FES except as described below and on the table at the end
of this summary.

The 1979 FES project boundaries totaled 138,500 acres for project facilities and
mitigation. Lands to be acquired for Mishak NWR totaled 13,800, of which
8,500 acres were outside the project boundaries. A total of 5,300 acres of
Stage 5 lands to be acquired for Mishak NWR were within project boundaries and
were to be purchased in fee title. The revised proposed plan, which includes
Russell Lakes NWR, would not require fee acquisition of the 5,300 acres of land
nor the 8,500 acres of land outside project boundaries. Thus, the amount of
land within the proposed project boundaries is now 130,000 acres.

The FES (1979) stated that 95 to 165 wells would be required. From 30 to
55 wells would be required in Stage 1-2; 25 to 40 in Stage 3; 25 to 40 in
Stage 4; and 15 to 30 in Stage 5. The total estimated for all stages is now
179 wells. The number of wells estimated for Stages 3, 4, and 5 have not
changed. However, if the number of wells should change in these stages, there
would be no additional environmental impact.

It has been determined that use of pipe stands and surge tanks is the most
dependable and economical method for controlling surge in the pipelines. In
Stage 1-2, 52 pipe stands and surge tanks will be required. Pipe stands will
range in height from about 10 to 25 feet above ground and have diameters ranging
up to 72 inches. Surge tanks will range in height from about 15 to 25 feet
above ground with diameters ranging up to 78 inches. These structures will
not be obvious from existing major highways in the area. The 1979 FES did not
consider the use of surge tanks and pipe stands.

The unlined conveyance channel will be essentially as shown in the FES (1979)
except that the alinement has been moved one-half mile to the east of the
original alinement through the Alamosa NWR. The channel will be fenced to
prevent livestock entering the channel. As designed, the conveyance channel
will cross 3.1 miles of the Alamosa NWR, intersecting the existing Chicago and

c

r ,~ ./1 r-. -. ,
\_: ''''.,; t '.)