less than ten centimeters. After a storm, a very small percentage of particles had a diameter of less than one millimeter. Slightly under 10% of the particles had a diameter of less than one centimeter. 80% to 90% of the particles had a diameter of less than ten centimeters. The Manning formula values on Wallace Run were 0.039 on July 31 and August 1, 2009 and 0.046 on October 24, 2009. Geology and geography Wallace Run is a coldwater freestone stream. In the upper eight miles, the main rock types are sandstone, red and brown shale, and gray conglomerate. The elevation of the creek at its headwaters is . For the first , the stream's elevation decreases at a rate of per mile, reaching an elevation of . For the next , the elevation falls at a rate of per mile, to . From this point to the mouth, the elevation decreases at a rate of per mile. The mouth is at an elevation of . The elevation of the entire Wallace Run watershed ranges from to . Ice caves and other ice formations have been observed to form on Wallace Run in the wintertime. Wallace Run has experienced damaging floods in the past. Past attempts to remedy this mainly focused on straightening the stream and lining it with rocks, increasing the velocity of the water. Landowners, as well as the area's governments, have attempted to add riprap and levees to the stream to improve its quality. Although initially these attempts were unsuccessful, the stream quality has improved. upstream of Wallace Run's mouth, the stream is in bankfull width and in bankfull depth. The actual depth, as measured in 2009, was . The discharge of the stream was measured to be 5.3 cubic meters per second on July 31 and August 1, 2009 and 4.5 cubic meters per second on October 24, 2009. The velocity of the stream on these dates was 1.28 meters per second and 1.09 meters per second, respectively. The Bear Rocks are a geological formation located on a hill northeast of Wallace Run. They are square blocks of sandstone that are "nearly as big as houses". The Wallace Run valley is high in the upper reaches of the stream. Watershed The area of the Wallace Run watershed is . The upper part of the watershed is mostly forested with some cabins, while the lower part is