Hypoxia in the Gulf of Mexico
Report Site Map > Monitoring Network for Nine Major Subbasins Comprising the Mississippi-Atchafalaya River Basin
In addition to the stations that are used to estimate delivery to the Gulf of Mexico, monitoring for flow and nutrient flux is conducted at 9 locations that are either on the main stem of the Mississippi River or are located on the major subbasins. Data from 16 stations are used to calculate flow and nutrient fluxes for major subbasins of the Mississippi-Atchafalaya River Basin at these 9 locations. The station locations are shown in figures 1 and 2 and pertinent station information is provided in table 1. The sampling station below Alton, Illinois, was relocated to below Grafton, Illinois, in 1989 after concurrent monitoring demonstrated that data from these stations were comparable. Flow data for these two stations were collected from stations adjacent to the water-quality sampling stations. Water-quality data for these two stations were combined in this analysis to yield a single long-term dataset. Nutrient flux estimates at the mouth of the Ohio River use flow data measured at Metropolis, Illinois, and water-quality data collected at Grand Chain, Illinois. Nutrient flux estimates for the Arkansas River use flow data measured near Little Rock, Arkansas, and water-quality data collected below Little Rock, Arkansas. For all other stations, flow and water-quality information is collected at the same station. Sampling is active for all nine major subbasins as of 2006. Seven of the nine subbasins are currently part of the National Stream Quality Accounting Network (NASQAN) Program network. The Red River at Alexandria, Louisiana, and the stations on the Mississippi River at and below Grafton, Illinois, are supported by other U.S. Geological Survey activities. |
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Station Name | Station ID |
Drainage Area (km2) |
Map No. | Data Type | Source |
---|---|---|---|---|---|
Mississippi River at Clinton, Iowa | 05420500 | 222,000 | 1 | flow and quality | USGS |
Mississippi River below Grafton, Ill.1,2,3 | 05587455 | 443,700 | 2 | quality | USGS |
Mississippi River at Grafton, Ill. | 05587450 | 443,700 | 2 | flow | USGS |
Mississippi River below Alton, Ill.1,2,3 | 05587550 | 444,200 | 2 | quality | USGS |
Mississippi River at Alton, Ill. | 05587500 | 444,200 | 2 | flow | USGS |
Missouri River at Omaha, Nebr. | 06610000 | 836,000 | 3 | flow and quality | USGS |
Missouri River at Hermann, Mo.4 | 06934500 | 1,353,000 | 4 | flow and quality | USGS |
Mississippi River at Thebes, Ill.5 | 07022000 | 1,847,000 | 5 | flow and quality | USGS |
Ohio River at Cannelton Dam at Cannelton, Ind. | 03303280 | 251,000 | 6 | flow and quality | USGS |
Ohio River at Dam 53 near Grand Chain, Ill.1,6 | 03612500 | 526,000 | 7 | quality | USGS |
Ohio River at Metropolis, Ill. | 03611500 | 525,800 | 7 | flow | USGS |
Arkansas River below Little Rock, Ark.1 | 07263620 | 409,964 | 8 | quality | USGS |
Arkansas River near Little Rock, Ark. | 07263450 | 409,300 | 8 | flow | USGS |
Red River at Alexandria, La.7 | 07355500 | 175,000 | 9 | Flow and quality | USGS and USACE |
Atchafalaya River at Simmesport, La. | 03045 | 226,800 | 9 | flow | USACE |
Old River Outflow Channel near Knox Landing, La. (Total Outflow) | 02600 | -- | 9 | flow | USACE |
1 | = | Flow measurements are used from nearby stations, which are identified in the next row. |
2 | = | The sampling station below Alton, Ill., was relocated to below Grafton, Ill., in 1989. |
3 | = | Subbasin includes one upstream subbasin (Map Number 1). |
4 | = | Subbasin includes one upstream subbasin (Map Number 3). |
5 | = | Subbasin includes four upstream subbasins (Map Numbers 1 through 4). |
6 | = | Subbasin includes one upstream subbasin (Map Number 6). |
7 | = | Flow data augmented by measurements at the stations identified in the next two rows. Additional flow data details are available. |
USGS | = | United States Geological Survey |
USACE | = | United States Army Corps of Engineers |
Report Site Map > Monitoring Network for Nine Major Subbasins Comprising the Mississippi-Atchafalaya River Basin