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10.3 Field Investigation Surveys and Data Collection <br />It was imperative that forensic information be gathered at the site as quickly as possible prior to <br />site degradation. Once the CDHS & EM had moved from response to recovery mode of the <br />disaster, the Dam Safety Branch requested access to shuttle engineers and survey equipment to <br />the site. Over the course of two days, September 24 and 25, 2013, five DSB engineers were <br />transported to the site to conduct the field investigations and surveys. <br />During the field investigation the Dam Safety Branch engineers measured the dam breach <br />geometries and obtained a photographic record of the dam failures. Longitudinal sections along <br />the dam crest and across the breach of each dam were surveyed by traditional direct -level <br />methods. Stationing along the sections was recorded with an extended -reel tape and digital range <br />finder. Spillway dimensions, dam crest widths, locations of upstream and downstream <br />embankment toes, and outlet works were also documented. Photos of the dam breaches <br />observed during the field surveys are presented in Figures 9 through 13. High water marks were <br />estimated on the slopes adjacent to each dam based on the accumulation and settling out of <br />organic duff and debris as shown in Figure 14. Bent grass indicative of overtopping flows was also <br />observed on the crests and downstream slopes of the remaining embankments and is shown in <br />Figure 15. <br />Figure 9 - Sunset dam breach looking across and downstream from left abutment. <br />Report of the September 2013 Little Thompson River Floodi ng ` COLORADO <br />and Big Elk Meadows Darn Failures, June 2014 (Revised, Dec 2014) Division at Water Resources <br />Page 15 of 48 <br />DAM SAFETY BRANCH <br />