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. . . Flows overtopped the BNRR at several locations. At Town of Atwood, lID estimated 20,500 cfs overtopped the railroad and returned directly to the South Platte River. Approximately 5500 cfs overtopped the railroad just to the south of the Riverside Cemetery. Additionally, existing bridges/culverts allowed flood waters to go under the railroad embankment. The Pawnee Creek main channel bridge was estimated to have carried only 1800 cfs, and the bridge approximately 1500 feet to the north had an estimated 500 cfs. Location of these overflows is shown on Figure 2. Flow widths for the surveyed cross-sections across the Pawnee Creek floodplain ranged from about 1,600 feet at the upstream end, over one mile at the downstream end. The flow depth in the confined channel at the upstream area was over 11 feet, while the flow depth closer to Town of Atwood was much more wide and shallow, with depths on the order of 4 feet in the community of Town of Atwood lIDd adjacent agricultural lands. Damage from this flood was estimated to have approached $20 million (County wide). About 1,400 residences and more than 200 businesses were affected by the flood. Flood waters damaged approximately 13,700 acres of agricultural land in Logan County. Damage to roads, bridges and highways were approximately $1 million. The following table presents a summary of estimated flood damages resulting from the flood. Table 5. 1997 Flood Damage Summary . . . Estimated Damage .. .. . . Damage Category .. ... Sterling. . County Total .. l. Residential $8,900,000 $ 870,000 $ 9,770,000 2. Commercial $1,370,000 $ 1,370,000 3. Agricultural $6,850,000 $ 6,850,000 4. Roads/Bridges/Highways $1,000,000 $ 1,000,000 5. Railroad $ 100,000 $ 100,000 Totals $19,090,000 The 100-year floodplain for the Pawnee Creek Overflow for the existing channel conditions was presented in the report entitled "Flood Plain Information and Drainage Plan For Sand Creek and the Pawnee Overflow At Sterling, Colorado" dated May, 1983 and prepared by Charles Leaf and Resource Consultants. This base engineering data was used for the Community's Flood Insurance map, and also the basis for the damage analysis. Approximate limits of the floodplain are shown on Figure 5. Flood flows for the 100-year flood coming into Sterling from the Pawnee Creek overflow were estimated to be 5000 cfs. This compares to the calculated Pawnee Creek overflow peak of approximately 3800 cfs during the 1997 flood. Figures 6 and 7 are photos taken during the 1997 flood, but before the peak hit. III-3