SWSI Environment and Recreation Needs and Priorities TRT Draft

• Technical Roundtable: Recreation & Environment
• Title: SWSI - Environment and Recreation Needs and Priorities White Paper
• SWSI II - Doc Type: White Papers

The calculated RV A metrics are then used in the model to set monthly reservoir release targets
to maximize the amount of time instream flow criteria are met. The release targets subsequently
constrain model yield calculations in the model. Significant outputs associated with these
simulations include reservoir firm yields and rates of attainment of instream flow targets.

Numerical analyses were performed with the WatSIT model, described in Section 7 and
Appendix F of the SWSI Report, to illustrate how an environmental option might be
quantitatively incorporated into the planning of a new water supply project.

As an illustrative example, Figure 1 shows storage to yield curves for a hypothetical reservoir
located on Leroux Creek in the Gunnison River Basin. Predicted yield versus storage values are
a function of legally available flows for the site (as simulated by the Gunnison River Basin DSS,
described in Section 7) and assumed monthly evaporation. Two curves are shown in this figure
corresponding to:

Alternative A - A management alternative in which the reservoir is allowed to completely
empty.

Alternative B - A management alternative in which a minimum pool volume of 30 percent of
capacity is maintained as a recreational option.

7,000

6,000

1,000

Average Annual Available Flow = 14,600 AF

5,000

>=
~ 4,000

"C
Gi
.~ 3,000

\t:

.. ..
~~~~~~~~~~~~~~~~~;~-~~~~~~~~~~~
..

~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ----- ~~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
.. --

.,.

.,.

2,000

.,.
~ ~ ~ ~ ~ -.-~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
.,.

.,.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
#

o
o

2,000

4,000

6,000

8,000

10,000

12,000

14,000

reservoir size (AF)
1-001<> minimum storage pool - - 3001<> minimum storage paoli

Figure 1
Example Storage to Yield Curve for Environmental and Recreational Options: Minimum Pool
Leroux Creek Reservoir - Gunnison River Basin: Agricultural Use

~5\^ISI

S.lal~.....ide WeIer Supply Initiclive

DRAFT

CDIVI

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