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<br />. <br /> <br />. <br /> <br />. <br /> <br />01G,j <br /> <br />llYdTology <br /> <br />Flood Control <br /> <br />The calculated inf'low design flood for the Narrows Reservoir will <br />have a peak discharge of 344,000 second-feet and a 20-day volume of <br />1,363,000 acre-feet. This flow results from a design rainstorm <br />superimposed on a leading snow flood with a runoff of 10,000 c.f.s. <br />The drainage area above the damsite is about 13,450 square miles. <br /> <br />To provide regulation for floods, the reservoir would have a <br />joint use pool of 75,000 acre-feet, a flood control pool of 475,000 <br />acre-feet, and surcharge capacity of 575,373 acre-feet. The river <br />outlet discharge would be limited to 5,000 c.f.s. during filling of <br />the flood control space. The outlets are to be designed for 8,600 <br />c.f.s. and the spillway discharge for 27,600 c.f.s. <br /> <br />Quality of Water <br /> <br />Quality of water analyses were conducted on streamflows within <br />the unit area during the 1947-1963 period. Samples for testing were <br />taken at the gaging stations near Kersey, Balzac, Crook and Julesburg <br />during most months of the year and at various stages of streamflow. <br />The tests were made in order to forecast the nature and severity of <br />problems which might be encountered from using the water for future <br />irrigation. The factors taken into account in the analyses were the <br />boron content, the ratio of sodium ions to the combined calcium and <br />magnesium ions, and the total salinity of the water. <br /> <br />'['he results indicate that the boron content is low and a <br />favorable ratio exists between the sodium ions and the combined <br />calcium and magnesium ions. With respect to total salinity, the <br />analyses show that during high stages of flow the quality is <br />entirely satisfactory in all reaches of the project area. During <br />low stages, however, the salinity increases appreciably, but not to <br />the point where use of the water is hazardous for irrigating the <br />porous types of soils which are characteristic of the Narrows service <br />area. <br /> <br />The results further show that the flows near Crook, Colo. <br />are of lower quality than those at the other testing points <br />including the Julesburg station near the Colorado-Nebraska State <br /> <br />69 <br />