WSP05686

• File Number: 8064
• Description: Section "D" General Federal Issues/Policies - Indian Water Rights
• Date: 10/14/1983
• Title: Water Conservation and Western Water Resource Management ‎(Draft)‎
• Water Supply Pro - Doc Type: Report/Study

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Interstate Apportionment

The interstate apportionment of water is also a difficult

issue. A Special Master in Colorado v. New Mexico awarded the

State of Colorado 4,000 acre feet annually from the Vermejo River,

which flows into and has been completely appropriated within New

Mexico. In reviewing the case, the Supreme Court recently noted

that the doctrine of prior appropriation is not the sole basis

for allocating waters between states. The Court further stated

that, ". ..in an equitable apportionment of interstate waters,

it is proper to weigh the harms and benefits to competing states."

In addition, efficiency of use in respective states must be considered,

while protection of "existing economies," which have been built

up through the use of water, "will usually be compelling." However,

a proposed diversion can overcome an existing diversion where

the state seeking the diversion demonstrates "by clear and

convincing evidence" that the "benefits of the diversion

substantially outweigh the harm that can result."

The Supreme Court remanded the suit for the Master to make

specific factual findings regarding the following: (1) the existing

uses of water from the Vermejo River: (2) the available supply

of water from the river, including the possibility of substitute

sources of water to relieve the demand on the river: (3) the

extent to which reasonable conservation measures in both states

might eliminate waste and inefficiency: (4) the precise nature

of the proposed interim and ultimate use in Colorado of water

from the river, including the benefits that would result: and

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