Yampa River Basin Research Final Synthesis Report

Home Browse Search

In the Phase I and II scenarios, the municipal contract pool was assumed to be 1,668 of (Craig's allocation in the existing reservoir). In the O &M scenarios this pool was assumed to be 3,668 af. In the Phase I scenario, the industrial pool was assumed to be 8,310 af, the existing storage contract for the Craig Station. In the Phase II scenario, the industrial contract pool was assumed to be 17,310 of (9,000 of of the Tri-State contract in Stagecoach plus the existing 8,310 of already in Elkhead for the Craig Station). In the O &M scenarios, this pool was assumed to be 6,000 af. In the Phase I scenario, the enlargement pool was assumed to be 32,800 af. In the Phase II scenario, the augmentation pool was assumed to be 22,200 af. In the O &M scenarios it was assumed to be 3 1,5 10 af. Instream Flow Rights or Targets The Phase I Study represented a Juniper Canyon instream flow right based on the contemplated draft of the Juniper Project water rights. This instream flow right was assumed to have a 1954 priority, and was thus able to call out existing and future in -basin demands operating under rights junior to 1954. Subordination of the Juniper rights was not represented in this particular scenario; however, the enlarged reservoirs were assumed to fill ahead of the instream flow right under portions of the Juniper priority "peeled off' for that purpose. The Phase II and O &M studies assumed no instream flow water right. In -basin demands were assumed to operate in priority and to deplete the river without regard to effects on instrearn flows. Reservoir releases were then made to augment instream flows at the Maybell gage so as to bring those flows up to various target flow levels. Although the CWCB began the process of obtaining an instream flow water right at Maybell, the model scenario presented here assumed those CWCB filing amounts were treated only as flow targets. Table 1 summarizes the instream flow rights and targets represented in the six scenarios. Results of Scenarios Table 2 shows the effects of the 1954 instream flow right, simulated in the Phase I Study, on flows in Juniper Canyon. Tables 3 through 7 show the Maybell flows resulting from flow augmentation operations simulated in the Phase II and O &M studies. The shaded cells in Tables 3 through 7 reveal occurrences of Maybell flow below the relevant target and indicate that natural flow and storage were inadequate to meet those instream flow levels. Tables 8 through 12 show the corresponding monthly storage releases for instream flow from the augmentation pool in the enlarged Elkhead Reservoir; these release amounts include evaporation charged to the augmentation pool, and also reflect reservoir fill administration based on an April 1 start-fill date. Appendix A Hydrosphere Resource Consultants, 1002 Walnut Suite 200, Boulder, CO 80302 3