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./ C6 1f '5 0 f C/?[J;rJ,eer/ S TECHNICAL WRITE UP JAMES CREEK AND LITTLE JAMES CREEK BOULDER COUNTY, COLORADO A. Area Studied James Creek,was studied by detailed methods from its mCluth to a point just upstream of Jamestown, Colorado. Little James Creek, II left bank tributary of James Creek was also studied by detailed methods frcG its mouth to a point about 0.25 miles upstream. The' total length of ~'ames Creek studied was approximately 3.5 miles. Stream bed elevations rar.ge from 6325 feet mean sea le~el (m.s.1.) to 6995 feet m.s.l. on James Cl'eek and from 6955 feet m.s.l. to 7049 feetm.s.l. on Little James Creek. BOth streams can be classified as steep mountain streams. Bed slopes range from .015 ft/ft (79.2 ft/mile) to.054 ft/ft (285.1 ft/mile) on James C~eek. . .Bed slopes . on Little James Creek range from .030 ft/ft (158.4 ft/mile) to ~290 ft/ft (1531. 2 ft/mile). .Little James Creek drains approximately 2.9 square miles. James Creek has a total drainage area of about 18.7 square miles. B. Sources of Data and Records Ground photographs of the 1969 flood'on James Creek at Jamestown were provided by the Colorado Water Conservation Board. These photographs were obtained from the Boulder Daily Camera. A etream discharge measurement for.the.1969 flood .0n..James .Creek was obtained from Water Resources Data for Colorado, Water Year 1969, published by the U.S. Geological Survey. Cross section data and topographic mapping having a contour interval of 2 feet and a scale of 1:1200 were established by photogrammetric methods from flights' made on 19 April 1978. These data were supplied by the Colorado Water Conservation Board and Boulder County. U.S. Geological Survey 7.5-minute quadrangle mapping with 40 foot contour intervals at a scale of 1:24,000 were also used in the study. Bridge data was supplied by the ~olorado Water Conservation Board. Some flood history was obtained from a flood insurance study for the town of Jamestown con- ducted by the engineering firm of Howard,Needles, Tammen, and Bergendorff for the Federal Emergency Management Agency. Two publications provided general information on past floods. The first was entitled 'Floods in Colorado, Water Supply Paper 997, published by the U.S. .Geological Survey. The second was entitled Flood Plain Information, Lefthand Creek, Volume I, . Boulder County, Colorado, published by the Corps of Engineers for the Denver Regional Council of Governments in January 1969. Stream gaging . records 'used in this study are listed in Table 1: