WSP01520

• File Number: 8510.100.60
• Description: Rio Grande Compact Commission
• Basin: Rio Grande
• Water Division: 3
• Date: 1/1/1951
• Title: Thirteenth Annual Report of the Rio Grande Compact Commission 1951
• Water Supply Pro - Doc Type: Annual Report

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commenced when this sum equals the total physical capacity of that
reservoir, to the level of the uncontrolled spillway i.e.-2,219,000
acre feet in 1942.

(c) All water actually spilled at Elephant Butte Reservoir, or
released therefrom, in excess of Project requirements, which is cur-
rently passed through Caballo Reservoir, after the time of spill,
shall be considered as Actual Spill, provided that the total quantity
of water then in storage in Elephant Butte Reservoir exceeds the phy-
sical capacity of that reservoir at the level of the sill of the
spillway gages, i.e.-l,830,000 acre feet in 1942.

(d) Water released from Caballo Reservoir in excess of Project
requirements and in excess of water currently released from Elephant
Butte Reservoir, shall be deemed Usable ~ater released, excepting
only flood water entering Caballo Reservoir from tributaries below
Elephant Butte Reservoir.

EVAPORATION LOSSES LJ.. t:i

The Commission shall encourage the equipping, maintenance and
operation, in cooperation with the United States Veather Bureau or
other appropriate agency, of evaporation stations at Elephant Butte
Reservoir and at or near each major reservoir in the Rio Grande
Basin within Colorado constructed after 1937 and in New Mexico con-
structed after 1929. The net loss by evaporation from a reservoir
surface shall be taken as the difference between the actual evapora-
tion loss and the evapo-transpiration losses which would have occur-
red naturally, prior to the construction of such reservoir. Changes
in evapo_transpiration losses along stream channels below reservoirs
may be disregarded.

Net losses by evaporation, as defined above, shall be used in
correcting Index Supplies for the operation of reservoirs upstream
from Index Gaging Stations as required by the provisions of Article
III and Article IV of the Compact.

In the application of the provisions of the last unnumbered
paragraph of Article VI of the Compact:

(a) Evaporation losses for which accrued credits shall be re-
duced shall be taken as the difference between the gross evaporation
from the water surface of Elephant Butte Reservoir and rainfall on
the same surface.

(b) Evaporation losses for which accrued debits shall be re-
duced shall be taken as the net loss by evaporati~n as defined in
the first paragraph.

Lk Amended at Tenth Annual Meeting, February 14, 1949.
L2 Amended at Thirteenth Annual Meeting, February 24, 19,2,

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