Instream flow program

A. Background

The Colorado Water Conservation Board (CWCB) administers the state's Instream Flow Program.
The Colorado General Assembly authorized CWCB to acquire water rights for instream flows.
CWCB protects through "preservation of the natural environment to a reasonable degree" [1, 2].
Its approach is to ensure minimum flows.
Streams enrolled in the Instream Flow Program are shown in the map below.

Distinctive is that with CWCB's rights, water stays in the stream channel.
This is in comparison with consumptive use, for example, water removed for irrigation.
Prior-established water rights prevail, however, meaning that CWCB's rights may be junior.
CWCB may acquire rights, however, and, thereby, rise in seniority.
Acquisition can be by "purchase, bequest, donation,...lease, exchange or other contractual agreement" [1].
It cannot be by eminent domain or force [1].
Also, CWCB can accept the temporary loan of water rights under the existing rule [1].
Proposed changes would extend the loan duration [3].
That is, loans could be made during 5 years, not just 3 years, over a 10-year period.
And loans could be renewed for up to 2 more 10-year periods.
Trout Unlimited has expressed support for the proposed changes [4].

Eighteen of the study's 42 streams participate in the Instream Flow Program. (See Protections underway.)
The red lines in map 1 above show the streams having that protection [5].
Nine of those 18 have no surface water diversion structures.
Two have 1 surface water diversion structure each on private property: Bear and Roaring Forks.
They are shown below in map 2 with pink squares.
The remaining 6 have more than 2 surface water diversions, on private property.
For example, there are 7 authorized surface water diversions at Fish and Little Fish, a tributary of Fish [5].
For comparison, Stoner, which is not part of the Instream Flow Program, has 4 diversions [5].
There is very little non-federal land, that is, privately property, at higher elevations in the study area.
The result is very little water diversion; for example, none above Marguerite, as seen above in map 1.
Private properties at lower elevations at the main stem and the West Fork have multiple diversions.
This is seen below in map 2; private property is shown below in gray in maps 3 and 4.