PUB00126

• Year: 2000
• Title: Overview of the Rio Grande Compact: Colorado Perspectives
• CWCB Section: Interstate & Federal
• Description: Overview of the Rio Grande Compact: Colorado Perspectives
• Publications - Doc Type: Tech Report

their obligation since that time. What is required to accomplish this administration is the topic of this
paper and will be described in detail below.

Pertinent Colorado Water Law

When the State of Colorado achieved statehood in 1876, her corresponliing constitution included and
adopted the Doctrine of Prior Appropriation as the basis for the appropri/ition of the water. This was a
matter of necessity due to the water-short characteristics of many of th,~ streams in the. State. It was
recognized early on that because of the large numbers of competing appropriations that some judicial
confirmation would be required to allow for the orderly distribution of!the State's water. It was also
authorized by the legislature in 1883 that a State Engineer would be given the responsibility to administer
the water rights of the State.

As early as 1883, general adjudications were held on the Conejos River;which confirmed and decreed
water rights in relative priority based on the date of appropriation and theiamount required to satisfY the
irrigation requirements under each ditch. The first general adjudication th~t occurred on the Rio Grande
mainstem was signed on May I, 1896. These adjudicatory processes:}were widely noticed and all
individuals that had completed their appropriations were allowed to comefforward and provide proof of
their claims. The date of appropriation, the legal description of the point of diversion, the flow rate of the
appropriation and the use to which the water right was to be placed wa4 determined by the court and
confirmed. The court referee investigated each claim for accuracy, ranke<l the water rights according to
the appropriation dates and recommended the court decree them accordingly. The State Engineer, through
water commissioners, used these decrees to administer and deliver the available water to those who were
entitled to it. Subsequent supplemental adjudications would include all new or existing claims not
previously decreed and create additions to the water rights administrativ~J list. All water rights in these
subsequent adjudications were ')unior" to all previously adjudicate~ rights regardless of their
appropriation date. Therefore, a water right may have a very early appropriation date, but having failed to
participate in the original adjudication, would end up junior to all others in the original adjudication.

The following table describes the adjudication dates and the amounts decre~d in each on the two Compact
streams in Colorado. The Conejos adjudications include the Los Pinos and 1fte San Antonio rivers because
they are tributaries. It is readily apparent that the vast majority of the wateriavailable in both systems was
decreed by around the turn of the century. The hydrology of the two basinsjdescribed later in the text will
show the grossly over-appropriated nature of the two streams.

Rio Grande and tributaries

Conejos River and; tributaries

1896 - 3209 cfs
1903 - 2501
1916 - 678
1934 - 353
1959 - 765
1960 to present - 140
Total including instream flow - 9139 cfsTotal including instream flow - 4104 cfs

1883 - 1459 cfs
1890-1312
1914 - 502
1915 to present - 375

These adjudications established early on the system of administration that has followed for more than 100
years. Gaging stations were established on all streams that had become fuOy appropriated that allow the
water commissioners to determine the amount of water that was available f9r distribution. Recognition of
return flows and tributary inflow to the stream make the task even more i~teresting. On the Rio Grande
mainstem, gages were established routinely along the course of the river to:help recognize the changes in
the flow throughout the system. Through the years, the State Engineer has~11ired a staff of hydrographers