In Sec. 20, T. 133 N., R. 30 W.-At a point 1⁄2 mile above the Pillager bridge, at mile 11.8 a 15 foot dam would back the water 61⁄2 miles up the river overflowing 200 acres of wooded and pasture land. The length of the dam would be 300 feet at the water surface, and 400 feet at the top. The fall between the dam site and the mouth will be utilized by a power plant now being built. AVAILABLE HORSEPOWER. Records of flow from November 1881 to October 1882; June to November 1884; October 1896 to August 1897, and from June 1909 to date, are available for Crow Wing River. An unusually severe drought during 1910 so depleted the ground water that the minimum flow during 1910, 1911 and 1912 was in all probability less than the flow for an ordinary low year. The winter flow of 1897 was that of an ordinary low year, but that for 1882 was not. For this reason the latter year was disregarded in determining the flow for an ordinary low year. The following table shows the estimated horsepower based on the available records of flow: Although no topographic survey has been made of Long Prairie river, a tributary of the Crow Wing, there is available the following table of approximate elevations and distances compiled from various sources: Elevations and distances along Long Prairie River from mouth to Alexandria. From the records of flow of Long Prairie River the following table has been compiled to show the undeveloped horsepower between different points. To show the sanitary quality of the water in the Crow Wing River, and the extent to which this water is used for municipal supplies, data showing the source of municipal supply, and disposal of sewage have been compiled for all towns located on the Crow Wing or its tributaries. These data are given in the following table in order of location, beginning near the source of the river: Municipal water supply and sewage disposal of towns located on the Crow Wing and tributaries. From the preceding table it appears that the main river receives no urban sewage. The rural population for the entire drainage basin is 14.1 per square mile. Above the mouth of Long Prairie River none of the tributaries carry urban sewage, and as the rural population is small it is probable that the water contains comparatively few sewage bacteria. The Long Prairie brings in the drainage from 975 square miles, having a rural population of 19.4 per square mile. This stream carries the sewage from an urban population of 3.250, but this sewage is treated before it enters the river. SAUK RIVER. SOURCE AND COURSE. Sauk River drains an area comprising 821 square miles lying south of the basin of Crow Wing River and north of that of the Crow. The Sauk rises in Osakis Lake, in the southwestern part of Todd County, and flows southeastward to its junction with the Mississippi about 2 miles above St. Cloud. Its tributaries are not important. In its upper course Sauk River flows through a number of small lakes, such as Gurney, Roberts, Little Sauk, Saul and Horseshoe. In all, there are about 75 lakes in the basin comprising 1 per cent of the drainage area. Many of these lakes are small and have no visible outlet. TOPOGRAPHY, GEOLOGY AND FORESTATION. The surface of the basin is rolling and is in general 40 to 80 feet above the level of the Sauk. Altitude range from 1,050 to 1,400 feet above set level. The entire area is covered with blue till -a mixture of sand, gravel and clay, laid down during the glacial epoch―underlain by cretaceous sandstones and shales or Archean granite and syenites. Rocks outerop at a few places in the basin, notably near St. Cloud, where granite is quarried. The sand and gravels of the drift yield water to the springs that emerge along the stream and also to shallow wells. For half its length the Sauk forms the dividing line between. the prairie district and the region of original forest which lies north of the river as far south as Richmond. The country below Richmond was formerly included in the timbered belt, but the proportion of forested area has been greatly reduced by clearing. By far the greater part of the drainage basin is now under cultivation. RAINFALL AND RUNOFF. Rainfall records maintained at various points in the basin and extending over 10 years indicate that the mean annual precipitation in the upper part of the area is 26 inches; the lower part lies in a small zone where the rainfall as determined at three points is about 23 inches. During the winter months the average precipitation (equal to 21⁄2 inches of rainfall) is in the form of snow which remains. The wettest year was 1905 when the rainfall averaged 34 inches and the driest 1910, when the precipitation was about 13 inches. Runoff records of Sauk River have been maintained since 1909. During that period the annual runoff has varied from 1.30 to 1.96 inches or from 5 to 15 per cent of the rainfall. DRAINAGE AREAS. The following drainage areas have been measured in this basin : Drainage areas in Sauk River basin. Location. At highway bridge 3 miles west of St. Cloud in Sec. 9, T. 124 N., R. 28 W., 10 miles below the nearest tributary which enters at Rockville. Records available.-July 8, 1909, to December 31, 1912. Drainage area. --816 square miles. Gage. Chain, attached to bridge; datum unchanged since established. The gage is read twice a day and the mean of the readings is recorded as the mean for the day. Channel.-Permanent, except after periods of high water when changes are apt to occur. Discharge measurements.- Made from the bridge. Regulation. At the mouth of the river is a dam 9 feet high. Not only is the station above the influence of the dam, but the dam itself prevents backwater from the Mississippi River reaching the station. The first dam above the station is at Cold Springs, 15 miles distant. The opening and shutting of the turbine gates at this dam affect the flow at the gaging station during the low water season. Winter flow. From December to March the river is frozen completely - over in the vicinity of the gaging station and measurements are made through the ice to determine the winter discharge. Accuracy. The mean daily gage height during the low water season is subject to some error resulting from daily fluctuations in the stage of the river caused by control of flow by dams above the station, and therefore the records for that period can not be considered better than fair. |