Niangua River WATERSHED INVENTORY AND ASSESSMENT This information is based on the Niangua River Watershed Inventory and Assessment prepared by Robert G. Schulz Fisheries Biologist Missouri Department of Conservation Camdenton, Missouri For additional information contact Ron Dent West Central Regional Fisheries supervisor 2010 South Second St. Clinton, MO 64735 ACKNOWLEDGEMENTS This Inventory and assessment has been a team effort extending back to 1989. Numerous Fisheries Management personnel have made significant contributions including: Ron Dent, Kevin Richards, Chris Vitello, Craig Fuller, Phil Rockers, Joe Burns, Brian Miller, Jennie Wright, Tony Botello, Ben Henderson, Carl Wakefield, and Mike Bayless. Personnel from other current MDC divisions, including Forestry, Wildlife, Protection, Natural History and Design and Development have also provided invaluable assistance in this effort. The Missouri Department of Natural Resources, Missouri Agency, and U.S. Fish and Wildlife Service also made many databases available and provided special assistance. INTRODUCTION Water is the ultimate integrator. Water quality and biodiversity in aquatic ecosystems are reflections of the environmental quality of the watershed, the subsurface geohydrology, and the atmosphere. Land use and land cover in the watershed, and terrestrial and airborne pollution problems all impact water quality. Water is a universal solvent. It carries dissolved gases, nutrients, and minerals, and at least trace amounts of almost every substance it comes in contact with, from the air to the ground, and into streams and groundwater aquifers. Although the primary focus of this inventory and assessment is aquatic habitats and communities, we have attempted to view the Niangua Watershed as an ecosystem. The land, air, and water are inter-connected and must be managed with mutual consideration. The creation of this document was considered a secondary objective of our planning effort for the Niangua Watershed. Our primary objective was to thoroughly inventory and organize information about the watershed for day-to-day use and for future planning. DATA INVENTORY AND MANAGEMENT The inventory for this document included compilation of a large amount of data and creation of twenty-four databases (Table 1). These databases have been incorporated in a Geographical Information System (GIS) featuring ArcView ® software. Databases were structured to be as compatible as possible with available source databases, yet satisfy our needs. Data was obtained from numerous sources in various formats including hard copies of reports and computer printouts, database files and ASCII text files, and from personal communication. In order to easily determine whether sites described by legal description are located within the watershed, a diagram showing the sections within the watershed was created (Appendix A). Unique, four-character labels were assigned to each site including a letter code (A-Z) that is unique for each feature (e.g. A = animal waste point source). These labels are used to locate sites on maps, and can be used to relate records in multiple databases. Site labels were frequently included in the records extracted from these databases to create tables. In order to obtain UTM coordinates and produce maps, sites were plotted on 7.5 minute topographic maps and marked with the site labels. Then Missouri Department of Conservation’s (MDC) Design and Development Division digitized these sites with AutoCad ® software to produce layers for each feature. These layers were combined with layers including streams, roads, county boundaries, and other layers as necessary. MDC’s Design and Development Division provided the Universal Transverse Mercator (UTM) coordinates for each site and they were added to the watershed database files. These were used to create XY. event tables in ArcView ®, to produce coverages for each feature, and to create most of the maps in this document. Many of the databases must be updated periodically to add new information (e.g. Section 404, permits and fish collections). This process will hopefully be facilitated by increased coordination between agencies to maintain databases in compatible formats and to improve accessibility. The MDC Fisheries Biometrics and two multi-agency groups, the Missouri Resource Assessment Project (MoRAP) and the Missouri Spatial Data Information System (MSDIS) are addressing this problem. LOCATION The Niangua River (NR) is a sixth order tributary of the Osage River in west central Missouri. It originates in northern Webster County, at the confluence of its East and West Forks, about 7 miles north of Marshfield. In this document, the mouths of the Niangua and Little Niangua rivers are considered to be where they originally joined the Osage River before the Lake of the Ozarks was created. The mouths of all inundated tributaries to the Niangua and Little Niangua rivers are considered to be at the pre-inundated locations. The river meanders 120 miles to the north where it joins the Osage River (Osage Arm, Lake of the Ozarks, Figure 1). The largest tributary of the NR is the Little Niangua River (LNR), a fifth order stream which drains about one third of the entire watershed. The LNR originates in central Dallas County, near the town of Pumpkin Center. It meanders to the north and east 59 miles before joining the NR near stream mile 6 (SM 6). The lower 21 miles of the NR and lower 10 miles of the LNR were inundated in 1931 by Lake of the Ozarks (LOZ). The Niangua Watershed includes portions of six counties. Since only 500 acres of Benton County is within the watershed and includes negligible population and development, it is not included on many of the enclosed tables. The most detailed maps (Appendix B) divide the watershed into three subwatersheds as described below. The relative position of the three subwatersheds are shown in Figure 2. Figure 1. Base map of the Niangua River Watershed with stream names and springs. Figure 2. Lower Niangua, Upper Niangua, and Little Niangua River sub-watersheds. GEOMORPHOLOGY Physiographic Region/Geology/Soil Type The Niangua Watershed lies in the Salem Plateau subdivision of the Ozark Plateau physiographic region. The watershed is underlain with several hundred feet of Ordovician and Cambrian rock, largely dolomite (Harvey et al., 1983). The edges of the watershed lie in Jefferson City-Cotter dolomite, while streams cut into progressively older Roubidoux, Gasconade, and Eminence formations (MDNR, 1984). There is considerable subsurface movement of water in the watershed through solution dissolved channels in the fractured and jointed dolomite. As a result, karst features such as caves, sinkholes, losing streams, and springs are abundant. Streams which incise into the middle or lower Gasconade have well sustained base flows even during dry periods, due to ample groundwater supplies (MDNR, 1984). Streams which incise into the Roubidoux formation are frequently losing streams and sinkholes are common (Harvey et al., 1983). Soils in the watershed are classified as residual, alluvial, colluvial, and loess (Harvey et al., 1983). Residual soils consist primarily of material weathered from cherty dolomite, dolomite, and sandstone, and occur on the surface of steep slopes. When they develop in uplands from Roubidoux formations, and Jefferson City - Cotter dolomites, an impervious fragipan usually occurs 18 to 24 inches below the surface. Colluvial soils, which are soils deposited on lower valley slopes by erosion from more elevated sites, are limited in abundance. Alluvial soils are those transported by streams and deposited on level or gently sloping areas in flood plains. They range in size from silt to gravel. Loess soils are silty, windblown material which commonly occur on ridgetops. Watershed Area The watershed area of the entire watershed is 1,040 square miles. The LNR watershed is 320 square miles, which is approximately one-third of the drainage of the entire watershed. Watershed areas for all fourth order and larger streams and some third order streams are shown in Table 2. The watersheds of fourth order streams are delineated in Figure 3. Approximately 500 acres of the Niangua Watershed is within Benton County, 164,000 within Camden County, 279,000 within Dallas County, 49,000 within Hickory County, 96,000 within Laclede County, and 69,000 within Webster County. Stream Order Stream order was determined from 7.5 minute topographic maps for all streams in the watershed. The NR has two fifth order and 14 fourth order tributaries. The LNR has one fifth order and six fourth order tributaries. Table 2 lists all third order and larger streams in the Niangua Watershed. Table 3 lists the total mileage of third order and larger streams, and the portions inundated by LOZ and Lake Niangua. Channel Gradient Stream gradients were determined for all third order and greater streams from the 7.5 minute topographic maps shown in Figure 4 and a table of elevations and average gradients is presented in Appendix C. Gradient plots were also created, but they are not included in this document. The average gradient of the Lower Niangua River is 3.9 feet per mile, the Upper Niangua River is 5.4 feet per mile, and the Little Niangua River is 9.4 feet per mile. Figure 3. Watersheds of fourth order streams within the Niangua River Watershed. Figure 4. 7.5 topographic maps that include the Niangua Watershed. Table 2. Stream code, name, order, length, watershed area, and location for third order and larger streams within the