Precipitation and Temperature
The mean precipitation in the basin ranges from 38.4 inches near Jefferson City to 41.6 inches at Versailles in the southwestern portion of the basin (Table Hy01). May, June, September and October are the months with highest precipitation. January and February are the driest months. July is the hottest month, a temperature near 90°F can be expected. January is the coldest month with the average minimum in the upper teens. Climate statistics for the three National Weather Service sites, Jefferson City water plant, Eldon, and Versailles, in the basin are summarized in Table 1. Additional information can be found on the internet at the Midwestern Regional Climate Center's web site.
USGS Gaging Stations
The one active USGS gage station in the basin is on the Moreau River near Jefferson City (station number 6910750) (USGS 2002). This station was active 1947-74, 1975-79, and reactivated in 2000. There are four stations: (North Moreau Creek near California, Hazel Branch tributary near Wardsville, Burris Fork, and South Moreau Creek near Russellville) which have partial records for years between 1957-1979 (Table Hy02; USGS 1971, USGS 1980). Base low flows recorded for North Moreau Creek on 8-25-70 was 1.4 cfs; Burris Fork on 9-23-71 was 1.88 cfs; and South Moreau Creek on 9-23-71 was 8.29 cfs.
For additional information visit the USGS web site.
The average 25-year discharge of the Moreau River at the 06910500 USGS gaging station near Jefferson City was 381 ft3/sec (USGS 2002). For the period of record, Dec 1947-Sep 1974, the maximum discharge occurred on October 14, 1969 where a discharge of 24,400 ft3/sec was recorded. The lowest discharge, 0.1 ft3/sec, was observed on September 30, 1956. Peaks in average annual monthly discharge occur in March and June and minimums occur in August (Figure Hy01).
In 1970, Skelton analyzed base-flow data for many streams in Missouri. He estimated flows by regression analysis of base-flow recession characteristics to determine the amount of water that could be expected to flow in a stream during rainless periods of 30 days or less. For the Moreau River, gage 069105, the seven-day low flow for a recurrence interval of two years (Q2) is 6.5 cubic feet per second (cfs) (Skelton 1970). This means the minimum seven-day average flow will be less than 6.5 cfs at intervals averaging 2 years; or, the probability is 50% that the minimum seven-day flow will average less than 6.5 cfs in a given year. Table Hy03 summarizes low-flow data for gage stations on the Moreau River near Jefferson City and the North Moreau Creek near California.
Dam and Hydropower Influences
There are no hydroelectric generators nor major dams in the basin. However, there is a series of wood pilings crossing the North Moreau Creek (T44N, R16W, S3) about 1.5 miles downstream from the mouth of Straight Fork where a mill once operated.
Small impoundments are located on small tributary streams. In 1986, the number of dams six feet or higher impounding at least 50-acre feet or 25 foot high and impounding at least 15 acre-feet inventoried by the Department of Natural Resources numbered 73 in Cole, Miller, Moniteau, and Morgan counties (MDNR 1986). This is a relatively low number of lakes compared to other areas of the state.