FLOOD07696 - Laserfiche WebLink

Home Browse Search

I , 16 THE ARKANSAS RIVER-Fl.OOD OF JUNE 3-5, 1921. The statements of local residents and the measured maximum dis- charges of the tributary streams indicate two principal areas of intense rainfall. (See PI. L) The larger area, which is roughly ellip- tical, extends from the northern boundary of Pueblo County to the top of the "'Vet Mountains near Beulah, a distance of 30 miles, and from a point a short distance above the mouth of Rush Creek nearly to Pueblo, a distanco of 15 miles. The smaller area covers the south slope of the Pikes reak uplift, which forms the northern part of the mountain valley, and extends from a point above Skaguay reser- voir to a point 3 or 4 miles south of the river, a distance of 25 miles, and from Oil Creek to Beaver Creek, a distance of 11 miles. The two areas cO\Oer 550 square miles. EFFECT OF RESERVOIRS ON THE FLOOD. COllsidpl'ahle lllisiJlformation relati"e to the efree!. of reservoirs upon the flood was disscminntcd hy the ;';"111'1':11 'and ter/lJIi!'al pl'ess at the time of its oCI'lllTenee. Thel'e :lI'l~ thl'ee reservoirs of 1'011- siderable size within the areas of intense raiHi:lll, an,1 lione of these contributed to the main flood of ,June iJ.. The Schaeffer reservoir, on Beaver Creek, failed on ,June 5, causing the flood of that date, which was very severe in the ralley immediately below the mouth of Beaver Creek but flattened out farther downstream. The other two reservoirs, the Skaguay reservoir, on Beaver Creek, and the Teller reservoir, on Turkey Creek, safely withstood the flood. At the time of the main flood the three resen'oirs helped in a slight degree to reduce its magnitude by holding back a portion of the run-off above them. The Schaeffer reservoir, which had a capacity of 3,190 acre-feet, was formed by an earth dam across Beaver Creek in sec. 9, T. 18 S" R. 68 W. The dam had a maximum height of 100 feet above the bottom of the outlet and a length on the' crest of 1,100 feet. . Its average height was about 90 feet for the middle 500 feet of' its length. The width on the crest was 15 feet, the outside slope 2 to L ,and the inside slope 3 to 1. A freeboard of 10 feet was provided. A concrete cut-off wtlll was provided in the middle pOltion of the dam, and a timber cut-off wall for the remainder. The inlet was a concrete tunnel 4 feet wide llnd 5 feet high, constructed on bedrock. The dam was built to :I hei/!ht. of 21) to 30 feet by the hydraulic- fill method when it was obsened that the material deposited in the center of the dam retnined water and di,.lnot consolidate, bcing more nearly liquid than solid. The liquid material was replaced by dry earth, and t.he dam was finishc(l by depositing the earth by wagons, sprinkling, and rolling in thin layers. The inner slope was rip- rapped to the top. A spillway 100 feet wide was provided beyond