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The largest floodflow of record on Fortification Creek, 841 cubic feet per second (cfs), occurred in March 1947. Studies indicate, however, that the actual flow may have been considerably greater due to overbank flows that were not measured or to ice conditions that caused inaccurate gage readings. Also, on the basis of a high-water mark (flood date unknown), the Colorado Department of Highways computed a peak flow of 1800 cfs on Fortification Creek. In March 1971, a snowmelt flood on Cedar Mountain Gulch inundated developing areas near the U.s. Highway 40 culvert crossing. Flood- water ponded to a depth of more than 6 feet on the upstream side of the culvert, but did not flow Over the top of the road. On the basis of the limited information available, it is estimated that a peak flow between 200 and 300 cfs occurred, determined to be less than a 20-year flood. Flooding from summer cloudburst type storms have occurred in and around Craig, but little definitive data on this type of flood event are available. A small thunderstorm (0.45 inch of rain in 2.5 hours) on July 20, 1974, resulted in a measured flow of 102 cfs on Cedar Mountain Gulch; this was also calculated to be less than a 20-year flood. More than 2 inches of rain in 1 hour, however, has been recorded in the Craig area. NO information on flood events on Brotherton Gulch, Pine Ridge Gulch, Lay Creek, Big Gulch, Sand Gulch, Sand Gulch Tributary, or Tributaries 1 and 2 is available. 2.4 Flood Protection Measures In 1979, the Denver and Rio Grande Western Railroad built a Craig bypass railroad line along the northern side of Yampa River. This line was constructed at a higher elevation than the 500-year flooding of Yampa River and, therefore, has reduced the limit of both the 100- and 500-year flooding to the north of Yampa River. Following the 1947 flood in Craig, Fortification Creek was improved under emergency repair and restoration authority available to the U.s. Army Corps of Engineers. The work consisted of cutting a new, straight channel in the lower reach of the creek; straight- ening and improving the creek upstream from the new channel section; and providing low, spoil type levees. This work, plus substantial natural channel improvement due to increased flow velocities, has materially decreased ice jam problems. Ice jams have occurred in recent years at the railroad crossing downstream from U.S. Highway 40, but they have been removed by city and railroad mainten- ance crews. Aside from the emergency maintenance work described, which was completed in 1949, no formalized flood control projects have an effect in the study area. 9