Collie Hollow Watershed Report

Watershed Area2
• County: Pulaski, Missouri
• Length of Segment: 8.2km
• Legal Start: SE NE NE 6 35N 7W
• Legal End: SW NW SE 4 35N 8W
• River Basin: Upper Gasconade
• Map Sheet: Ozark Springs, Brownfield (HUC # 10290201-070)
• Land Feature: Valley

County Demographics3
• Population (1990): 41,307
• Land Area: 547sq.mi.
• Population Per Sq. Mile: 76

Precipitation Patterns6
At this latitude precipitation in the form of rain or snow is affected by temperature, which has an annual mean of 42E F. Rain has the effect of quickly recharging groundwater and surface water, where snow melt has a gradual effect on surface water hydrology. The average annual precipitation at Rolla, MO (east of watershed) and Lebanon (west of watershed) was 41.09 and 41.37, respectively, inches over the period 1961-90 (Owenby and Ezell 1992). The arithmetic watershed precipitation mean is 41.66 inches.
Precipitation for the 1960-96 period of record indicated that the winter seasons and growing seasons (April to November), as defined by the SCS Wright County Soil Survey, had year-to-year cyclic patterns as seen in Figure 1 below.

Vegetative Cover
The region is forested however large areas have been cleared for agriculture and grazing.   Along the stream banks you can find native vegetation consisting of trees, shrubs and grasses.   The riverbanks are generally blanketed with such vegetation except in the area near Highway T.   This area has been cleared for cattle grazing and agriculture.   The vegetative cover extends about five feet away from the riverbanks before major clearing occurs.

Surface geologic formations are composed of dolomite and sandstone of the Ordovician Age. All geologic formations in the watershed are part of the Canadian Series (MDNR 1979). Tributary streams and the main stem Gasconade River cut through a member of the Gunter Sandstone, the Gasconade Formation. This formation has many springs that contribute to the base flow of the main...