AZ vs. CA:22 California Exhibits, Vol. XXII; Nos. 5001-5002; 5101-5123; 5200A-5205A; 5521-5588A; 5601-56215521-5588A; 5601-5621

page 12

12 COLORADO RIVER STORAGE PROJECT CONSTRUCTION SCHEDULE Expenditures by the Bureau of Reclamation for advance planning and construction of the authorized storage units and participating projects are tentatively programed as shown in the schedule on the following page. Construction already has been started on the principal features of the Colorado River storage project, except those of the Curecanti unit. The first participating projects programed are the Paonia, Hammond, and Seedskadee projects and the Vernal unit of the central Utah project, all of which are scheduled for the start of construction in fiscal year 1961. The advance planning and construction schedule has been followed in the economic and financial analysis discussed later in this report. The program as now outlined could be substantially modified, however, as actual progress will be determined by congressional appropriations. It will be desirable for work on the storage project to follow the general rate established by contracts now in force and to be awarded in fiscal year 1958. Any slowdown in the rate established would increase costs of interest during construction and in the case of the Glen Canyon and Flaming Gorge units would delay availability of power revenues to assist in repayment of irrigation costs. Water Supply Water supplies available for development by authorized units of the Colorado River storage project and participating projects have been estimated on the basis of recorded flows, with consideration given to downstream uses and past and anticipated upstream depletions. It is not within the scope of this report to summarize the water-supply studies made for each participating project. A brief summary of the water supply available to the Upper Colorado River Basin and units of the storage project is presented in the following paragraphs, however, in view of the importance of water supply as related to project power production and revenues. STREAMFLOWS Three terms are commonly used to define flows of the Colorado River. Historical flows are those which have actually occurred. Virgin flows are the estimated flows which would have occurred without man-made depletions. Present modified flows are those which would have occurred in the past had the present level of development and depletions been in full effect. Average annual historical and present modified flows at units of the storage project have been estimated as shown in the following table. Average annual flows for 19H-1945 period 1 [In acre-feet] Unit Historical flow Present modi-fled flow Glen Canyon........................ Flaming Gorge.-...........________ Navaho______.................____ Curecanti (Morrow Point Dam site). 13, 763,000 1,636,000 1, 260,000 1,270,000 13,064,000 1,615,000 1,244,000 1,270,000 1 Period adopted in negotiations for the Upper Colorado River Basin compact as representative of longtime-flow conditions.