Page 14

12 RELEASE OF COLORADO RIVER WATER Date: Available flood-control storage space (acre-feet) August 1 2,500,000 September 1 2,500,000 October 1 2,500,000 November 1 2,675,000 December 1 3,963,000 January 1 5,350,000 (b) Releases from the reservoir shall be restricted to quantities that will not cause a flow in excess of 40,000 cubic feet per second at Needles, California, insofar as possible. (c) For the period January 1 to August 1, minimum releases from the reservoir to attain the August 1 flood-control space prescribed in paragraph (a) of this section shall be determined from tables 1 through 6 of the Tables of Minimum Average Releases for Flood Control Purposes currently in force for various conditions of available flood-control storage space and a maximum forecasted inflow. The Tables of Minimum Average Releases for Flood Control Purposes currently in force as of the promulgation of this section are those dated January 27, 1954, File No. 373/102. Pertinent information on inflow forecasts and on permissible changes in the releases indicated in tables 1 through 6 of the Tables of Minimum Average Releases for Flood Control Purposes currently in force is given in subparagraphs (1) and (2) of this paragraph. (1) All inflow forecasts used in carrying out the provisions of the regulations in this section shall be prepared by the Bureau of Reclamation. The maximum forecast for any specified runoff period is defined as the estimated inflow volume (acre-feet) that, on the average, will not be exceeded 19 times out of 20. (2) When minimum releases for the periods April 1 to August 1, May 1 to August 1, or June 1 to August 1 as given in tables 4, 5, or 6, are between 20,000 cubic feet per second and 40,000 cubic feet per second, it will be permissible to release less than the indicated amounts for a part of the period, provided the average releases for the entire period will equal the releases given in the table, without flows exceeding 40,000 cubic feet per second at Needles, California, gaging station. (d) For the period August 1 to November 1, minimum releases from the reservoir shall be determined daily from table 7 of the Tables of Minimum Average Releases for Flood Control Purposes currently in force for various conditions of available flood-control storage space and of estimated inflow. The inflow shall be estimated on the basis of discharge reports from appropriate gaging stations on Colorado River and on Little Colorado River. Pertinent information on permissible changes in the releases as indicated in table 7 is given in subparagraphs (1) and (2) of this paragraph. (1) Minimum releases from the reservoir as given in table 7 of the Tables of Minimum Average Releases for Flood Control Purposes currently in force, if 40,000 cubic feet per second or less, shall not be reduced, when once initiated, until the storage space prescribed in paragraph (a) of this section becomes available. (2) Minimum releases from the reservoir as given in table 7 of the Tables of Minimum Average Releases for Flood Control Purposes currently in force, if greater than 40,000 cubic feet per second, shall not be reduced, when once initiated, until the reservoir water surface has receded to elevation 1221,4 (top of spillway gates in raised position), or, if the reservoir water surface does not reach elevation 1221.4, until the inflow and reservoir water surface are both receding. Releases may then be gradually reduced to 40,000 cubic feet per second and shall be maintained at not less than that rate until the storage space prescribed in paragraph (a) of this section becomes available. (e) For the period November 1 to January 1, the minimum releases from the reservoir shall be those necessary to make available the storage space prescribed in paragraph (a) of this section. (f) Nothing in this section shall be construed to require dangerously rapid changes in magnitudes of releases. (g) The Bureau of Reclamation shall procure such current basic hydrologic data, and make such current calculations of permissible releases from the reservoir as are required to accomplish the flood-control objectives prescribed in this section. (h) The Bureau of Reclamation shall keep the District Engineer, Corps of Engineers, Department of the Army, in charge of the locality, currently advised of reservoir release, reservoir storage, and such other operating data as the DistrictEpson Perfection 4870 Photo, 400 dpi, 8 bit, 1,697,399 byte