Monitoring Network for Selected Mississippi-Atchafalaya River Subbasins with Varied Sizes, Hydrology, Land Use, and Geographic Location

Figure 1. Locations of 22 subbasins in the Mississippi-Atchafalaya River Basin with varied size, hydrology, land use, and geographic location that are used for estimating and studying nutrient fluxes. (Subbasin number is identified in table 1.) (Click on image for larger version)

In addition to the stations that are used to estimate delivery to the Gulf of Mexico, and the stations used to estimate nutrient fluxes of major Mississippi River subbasins, monitoring is conducted at stations located within 22 subbasins that vary in size, hydrology, land use, and geographic location. These subbasin drainage areas vary from 16,200 to 630,700 square kilometers.

The drainage areas of the 22 subbasins are shown in figure 1, and pertinent station information that defines these subbasins is provided in table 1. Sampling is active for 14 of the 22 selected subbasins as of 2006 as indicated in table 1. Four of the 22 subbasins (Wabash River at New Harmony, Ind., Tennessee River at Highway 60 near Paducah, Ky., Illinois River at Valley City, Ill., and Platte River at Louisville, Nebr.) are currently (as of water year 2008) part of the National Stream Quality Accounting Network (NASQAN) Program network, which is currently designed to collect data for larger subbasins.