Geology and Geomorphology
The South Grand River Watershed lies within the Osage Plains Subdivision of the Central Lowland Physiographic Region. The Osage Plains Subdivision is comprised of gently rolling plains with scattered escarpments, low mounds and a low relative relief of 50-150 feet (MDNR 1986). The Osage Plains were not glaciated unlike much of the Central Lowlands Physiographic Region. Elevations within the South Grand River Watershed range from a maximum of approximately 1,154 feet above mean sea level (msl) in the uplands to approximately 682 feet above msl in the lower portions of the watershed. Local relief data (local relief refers to the difference in elevation between two nearby points such as a valley and an adjoining ridge top) obtained from the Missouri Department of Conservation (MDC) Fisheries Research Fish Collection Database (1998a) indicates a minimum local relief of 43 feet and a maximum of 159 feet for MDC fish collection sites within the watershed.
The South Grand River Watershed occurs primarily within the Cherokee Prairies Soil Region. Allgood and Persinger (1979) describe the Cherokee Prairies Region as "... underlain with shale, sandstone, and limestone. Soils formed in residuum from shale are deep claypan soils. Soils formed from sandstone and limestone are more loamy, but in places on the ridges soils are shallow. Narrow bands of soils formed in deep loamy alluvium are adjacent to streams."
The soils of the Cherokee Prairies have been formed primarily beneath tall and mid-tall grasses with forest located on lower slopes and along streams (Allgood and Persinger 1979). A smaller portion of the South Grand River Watershed, primarily located in the upper portions of the watershed, occurs in the Deep Loess and Drift Soils Region. Allgood and Persinger (1979) describe the soils of this region:
"These soils are located in the northwest part of Missouri. The topography is mostly rolling to hilly, but some broad ridge tops are nearly level to undulating. Areas bordering major stream valleys have the steeper slopes. Nearly level areas of bottom land are adjacent to streams."
"Soils formed in a thin loess mantle over glacial till on the upper ridges while soils are developed in glacial till or loess and glacial till on the side slopes. Soils formed in silty and clayey alluvium on the flood plains of streams."
The soils of the Deep Loess and Drift Region were formed primarily beneath tall grasses on broad ridges with forest located on lower slopes and along streams (Allgood and Persinger 1979).
The following is a list of soil associations found in the South Grand River Watershed:
The geology of the South Grand River Watershed consists primarily of limestone and sandstone of Pennsylvanian age (Figure Ge01). Upland portions of the watershed are overlain by up to six feet of loess (MDNR 1992). Pennsylvanian aged clay also occurs in smaller, more isolated areas of the watershed. In the lower portion of the watershed, Mississippian limestone, limestone shale, and Ordovician dolomite are present (Figure Ge01). Coal deposites are present within the watershed and mining has occurred in the lower portion of the watershed. The presence of barriers to groundwater infiltration such as clay and shale within the Pennsylvanian bedrock as well as the limited storage capacity of the bedrock in the area have resulted in very few springs as well as poorly sustained stream base flows in dry periods (Vineyard and Feder 1974 and MDNR 1992).
Due to the nature of the geology of the watershed, the presence of karst features is very limited. Only 6 unnamed springs are known to occur within the watershed (MDNR 2000a). Five of these springs are concentrated in an area that appears to have been heavily strip-mined. The other spring occurs near Truman Reservoir. No flow data is currently available for these springs. In addition, no streams within the watershed are designated as "losing" in the Rules of Department of Natural Resources Division 20-Clean Water Commission Chapter 7-Water Quality (MDNR 2001).
Stream Order, Mileage and Permanency
Stream order is "a hierarchy in which stream segments are arranged" (Judson et al. 1987)
The process of stream ordering is accomplished by examining maps and assigning orders to stream segments based on other streams which flow into them. Using the Strahler/Horton method of stream ordering: when two stream segments of the same order join, the new segment they create is the next highest order. For instance, a first order stream would be a stream in which no other streams intersect it. A second order stream is created by the joining of two first order streams. A third order stream is created by the joining of two second order streams and so on. If the main channel of a stream happens to be a lower order than that of the intersecting stream, the main channel assumes the higher order. If the main channel is a higher order stream than the intersecting stream, it maintains the higher order (Figure Ge02).
Maximum orders for streams within the South Grand River Watershed have been obtained from a 1:24,000 scale Geographic Information System (GIS) hydrography coverage. There are 186 third order and larger streams within the watershed (Table Ge01 and Figures Ge03, Ge04, Ge05, Ge06, Ge07). These streams account for a total of approximately 1,552 stream miles or 28% of the total stream miles within the watershed. Of the 186 third order and larger streams within the watershed, 138 are third order (792.9 miles), 36 are fourth order (466.3 miles), 9 are fifth order (150.8 miles), and 1 is sixth order (76.0 miles). The South Grand is 66.4 miles long and becomes seventh order at the confluence of Big Cr.
Stream mileage per order for the South Grand River Watershed has been obtained from a 1:24,000 scale (GIS) hydrography coverage. A total of 5,640 miles of streams occur within the watershed. Approximately 3,250 miles (59%) are first order segments; 1,123 miles (20%) are second order; 561 miles (10%) are third order; 307 miles (6%) are fourth order; 140 miles (3%) are fifth order; 67 miles (1%) are sixth order; and 51 miles (<1%) are seventh order. Table Ge02 lists length by order for fourth order and larger streams within the South Grand River Watershed. Lengths were only for mainstems of streams.
Permanent stream mileage data obtained from a 1:24,000 scale GIS hydrography coverage for the South Grand River Watershed indicates that approximately 947 stream miles (17%) within the watershed have permanent water. This equals approximately 1 mile of permanent stream for every 2.2 square miles of drainage area. Estimated length of permanent flow for third order and larger streams is given in Table Ge01.
Total drainage area of the South Grand River Watershed is 2,046 square miles or 1,309,440 acres. The drainage area of the watershed in Missouri is 2,016 square miles or 1,290,240 acres. Drainage area for fourth order and larger streams was determined through analysis of 30 meter resolution digital elevation model of the watershed (Table Ge01 and Figure Ge08a). Fourth order and fifth order streams having the largest drainage areas are South Fork Creek (64 sq. miles) and Deepwater Creek (238 sq. miles) respectively. Big Creek, the only sixth order stream in the watershed, has a drainage area of 538 square miles. The South Grand River a seventh order stream has a drainage area of 1,329 square miles. This does not include tributaries drain flowing which today flow directly into Truman Reservoir. These have a combined drainage area of 717 square miles (excluding the South Grand) and include the drainages of Barker Creek, Tebo Creek, Little Otter Creek, Big Otter Creek, Cooper Creek, and Deepwater Creek.
In order to facilitate analysis of various watershed characteristics within this document, the watershed was divided based on eleven digit hydrologic units (Figure Ge08b). The largest of these units is the Middle South Grand Unit which drains approximately 418 square miles (267,449 acres).
Stream Channel Gradient
Channel gradient was determined for all fourth order and larger streams within the South Grand River Watershed using data digitized from USGS 7.5 minute topographic maps. Composite gradient graphs were constructed for all fifth order and larger streams within the watershed (Figures Ge09-23). Average gradients for fourth order and larger streams within the watershed range from 1.9 feet per mile to 39.4 feet per mile. The South Grand River has an average gradient of 1.9 feet/mile.