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 Lo01). 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 Lo02.