Utah Lake Management Plan Amendment

Dear Water User:

Re: modifications to Interim Utah Lake Management Plan

We have received several comments regarding the refinements to the plan which we re proposed at the October 28 public meeting. We have summarized the proposal and the comme nts received as follows:

1. Reporting on Transbasin Imports, Reservoir Releases, and Return Flow Credi ts.

Proposal
Each water user must report to the commissioner the rights under which the water is being imported, released, or spilled and its destination. If more than one right is involved the water user must report the quantity or proportion to each. Reports must be made prior to or concurrent with imports, releases or 'spills. Any changes in quantities, water rights, or destination must be reported within one day of such occurrences.

Water users desiring to claim return flow credits in Utah Lake must submit an annual report to the State Engineer prior to November 1 stating the amount of credit claimed, the water rights involved, and the basis for the amount of credit claimed.

Comments and Response

The comments received expressed support for the proposal, therefore it will be adopted as part of the 1994 interim management plan for Utah Lake.

2. Modifications to the System Storage Conversion Curve.

Proposal
The State Engineer will consider modifying the curve upon written request from a water user stating that water rights will not be exercised, the water rights involved, and the amount of water that will not be called for. Requests will be accepted only prior to April 1. Modifications to the curve will be based upon the amount of water to be left in Utah Lake. Leaving water in Utah Lake will not give the water user any other right in exchange for not calling for the water under the existing right.

Comments and Response

The comments received expressed support for the proposal, therefore it will be adopted as part of the 1994 interim management plan for Utah Lake.

3. Evaporation Losses on Import Water Held in Utah Lake.

Proposal
Two possible methods were presented at the meeting. One method would apportion evaporation losses based on the proportion of the import storage to the total contents of the lake. The other method would apportion the losses based on the incremental increase in surface area caused by the import water. Under either method evaporation losses will be calculated based on daily inflow, lake level, and climatological data. The modified Blaney Criddle method will be used with a coefficient of 1.35. Evaporation losses will be accounted for monthly.

Upon submission of claims for return flow credits, the evaporation incurred by the return flows will be estimated for the period prior to November and deducted from the claimed amount. After November 1, return flow credits will be charged with evaporation losses in the same manner as import storage.

Comments and Response

The comments received support the method of apportioning the losses based on the incremental increase in surface area caused by the import water. The comments reasoned that the import water should not be charged with any more loss than the increase in evaporation it caused to the lake. This appears to be a reasonable argument. Therefore the incremental surface area method will be adopted as part of the 1994 interim management plan for Utah Lake.

4. Transportation Losses on the Provo River

Proposal
The 1921 Provo River Decree states that a four percent transmission loss will be charged on the river until there is a better understanding of actual transmission losses. The decree indicates this transmission loss is to be charged against storage water, Weber River water, and Ontario Drain Tunnel water. The historical practice has been to charge transmission losses against import and storage water originating above Heber Valley.

Comments and Response

The comments received request that transmission losses on Jordanelle Reservoir releases not be implemented until the State Engineer evaluates available and forthcoming data related to the loss/gain regime of the river. It is somewhat unclear what data is being referred to, however, at this time the State Engineer does not have the manpower available to do an independent study of the losses on the river.

We believe there is some foundation for the historical practice which has developed concerning transmission losses and we are hesitant to change that practice until the hydrology of the river in this area is better understood. Therefore, the four percent loss will be charged (including new releases) until such time as an acceptable study is performed that conclusively demonstrates that this figure should be modified.

5. Evaporation on System Storage

Comment
Another issue raised in the comments which was not discussed at the public meeting relates to evaporation losses on system storage which later is called for by Utah Lake. Currently, the management plan does not charge evaporation losses against system storage. The comments propose that evaporation be charged against system storage at the same rate as the other storage in the particular reservoir. When system storage is called for bv Utah Lake, only the net system storage would be subject to release.

Response

The interim management plan does not contemplate charging evaporation losses against system storage, nor does it contemplate requiring releases to make up transmission losses incurred in moving system storage from the reservoirs to the lake. System storage will be called for very infrequently. If the need arises, both factors will need to be taken into account in the transfer of system storage to Utah Lake.

This is an issue which needs further investigation and consideration, therefore, this suggestion will not be implemented at this time.

One other minor modification to the plan was discussed at the meeting. It was proposed that Section 4.2.8 at line 26 on page 11 be modified to read as follows:
"Any time during the irrigation season when the storage [c a p a c i t y] in Utah Lake drops below ... "

No comments were received concerning this modification, therefore it will be ado pted as part of the 1994 interim management plan for Utah Lake.

The modifications described in this response will be implemented as part of the Interim Utah Lake Management Plan as of November 1, 1993. If you have further questions conc erning these items please contact Lee Sim, Assistant State Engineer for Distribution.

 
                                         Sincerely,

 
 
 

                                  Robert L. Morgan, P.E.

 

RLM:LHS:bd