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Flooding Problems and Flood History Flooding on Pawnee Creek can occur as a result of general rains over large areas, or from local thunderstorms over smaller areas. A significant flood event on Pawnee Creek occurred on June 14/15, 1965. A peak flow estimate of 35,200 cfs was indirectly measured at the Colorado Highway 14 bridge approximately 10 miles upstream from Atwood. During the 1965 event, overflows from Pawnee Creek flooded areas on the west side of Sterlling and did not affect the residential and business (downtown) areas on the east side of the city. The 1965 flood event was preceded by another large flood event in May of 1935. Discharge estimates for the 1935 event are not readily available. III. JULY 1997 FLOOD EVENT Heavy rains in northeast Colorado during the week of July 28, 1997 caused significant flooding in several areas including Fort Collins, Weldona, Atwood, and St.:rling. Rainfall over the Pawnee Creek watershed on the evening of July 29 saturated agricultural/range lands and caused major storm runoff in the tributaries and main channel. Flood wa[ers in the Pawnee Creek floodplain crested in Atwood at approximately 3pm on July 30. Flood waters from the Pawnee overflow first reached the south side of Sterling at about 4pm, and then crested in the downtown area around midnight on July 30th. Flood documentation was performed by the CWCB in cooperation with the Corps of Engineers (Omaha District) and the CSU Extension Office in Logan County. The majority of the field work for the flood documentation occurred on August 5-7, 1997. Team members for the flood documentation efforts are listed in Table 1. Table 1 - Flood Documentation Team >",.1'a' ~Q.<':>e~)!$.~,<~l~;~~&{t1i~;C,: -'~A: 'ffi" l^i.::1rt'I'o:-';;)'n-x.;:;P;~;;~flT11'%&i;:~d~Jr1}J*+-;;;:;}~.~~;,;; 'j,'":; >i-' III .c,_{-_ _';l4r_;:~}_/~ ,n'W,,'_ -" _' llil _ _,,-',ii",;:.~,,;i;;'~ .( ~ .;._~'~, ,,;T'~'<_,~ '{:J'C- ~;.,_,._O" '__ _"',/' '''. Colorado Water Conservation Board Colorado Water Conservation Board Colorado Water Conservation Board Co s of En meers, Omaha District Co s of En ineers, Omaha District Wes, CSU Extension Office, Logan County In addition, CWCB staff assisted the City of Sterling with flood fighting efforts on the night of July 30 and the morning of July 31. A video of the floodwaters in and around Sterling during the actual event was recorded by the CWCR Storm Characteristics and Rain/allIn/ormation A severe thunderstorm produced extremely heavy rain in Weld and Logan Counties on the evening of July 29 and into the early morning hours of July 30. Point rainfall amounts of up to 15 inches in a 4 to 8 hour time period were reported in the upper watershed areas of Pawnee 3