Missouri River Water-Quality Monitoring in Relation to Combined Sewer Overflow Systems near Omaha, Nebraska
In 2012, the USGS Nebraska Water Science Center, in cooperation with the City of Omaha, began monitoring the Missouri River near Omaha to document water-quality changes in the river as the City improved their combined sewer overflow (CSO) system. The monitoring program includes both discrete and continuous data collection at four sampling sites on the Missouri River. Monitoring at each site includes monthly discrete isokinetic, depth-integrated equal discharge water-quality sampling for nutrients, chlorine, biological oxygen demand, and total suspended solids; cross-sectional profiles of water-quality parameters; Escherichia coli grab samples; measurements of discharge; and continuous monitoring of water-quality parameters.
Monitoring at each site includes monthly and two yearly rain event discrete isokinetic, depth-integrated equal discharge water-quality sampling for
- nutrients,
- bacteria,
- biological oxygen demand,
- total suspended solids, and
- chlorine.
Each discrete water-quality sample collected is classified as wet local or dry local and Missouri River high flow or Missouri River normal flow.
Continuous Data
Continuous data is collected using water-quality monitors located at three sites along the Missouri River upstream from, in the middle of, and downstream from Omaha.
- Missouri River at NP Dodge Park at Omaha, Nebr.
- Missouri River near Council Bluffs, IA
- Missouri River near La Platte, Nebr.
The monitors deployed at each site collect data every 15 minutes for
- water temperature,
- specific conductance,
- dissolved oxygen,
- pH, and
- turbidity.
Monitoring Challenges
The monitoring program was designed to address a number of challenges:
- Flows from CSO’s are a very small portion of the larger Missouri River receiving waters being sampled.
- Trend detection is difficult because the hydrograph of the Missouri River within a year and between years is so variable.
- Contaminates can come from many upstream point and non-point sources which makes detecting what contaminates are coming from the Omaha area and which are coming from upstream sources hard.
- Simple grab samples do not represent the actual water quality of the river because the Missouri River is not well mixed.
Data Analysis
Data analysis now is beginning on the three and a half years of monitoring data collected so far. Information recorded during data collection such as local weather conditions, Missouri River conditions, days since last rain event, and amount of precipitation will be used to classify the data to understand how improvements to the CSO system has affected water quality.
In 2012, the USGS Nebraska Water Science Center, in cooperation with the City of Omaha, began monitoring the Missouri River near Omaha to document water-quality changes in the river as the City improved their combined sewer overflow (CSO) system. The monitoring program includes both discrete and continuous data collection at four sampling sites on the Missouri River. Monitoring at each site includes monthly discrete isokinetic, depth-integrated equal discharge water-quality sampling for nutrients, chlorine, biological oxygen demand, and total suspended solids; cross-sectional profiles of water-quality parameters; Escherichia coli grab samples; measurements of discharge; and continuous monitoring of water-quality parameters.
Monitoring at each site includes monthly and two yearly rain event discrete isokinetic, depth-integrated equal discharge water-quality sampling for
- nutrients,
- bacteria,
- biological oxygen demand,
- total suspended solids, and
- chlorine.
Each discrete water-quality sample collected is classified as wet local or dry local and Missouri River high flow or Missouri River normal flow.
Continuous Data
Continuous data is collected using water-quality monitors located at three sites along the Missouri River upstream from, in the middle of, and downstream from Omaha.
- Missouri River at NP Dodge Park at Omaha, Nebr.
- Missouri River near Council Bluffs, IA
- Missouri River near La Platte, Nebr.
The monitors deployed at each site collect data every 15 minutes for
- water temperature,
- specific conductance,
- dissolved oxygen,
- pH, and
- turbidity.
Monitoring Challenges
The monitoring program was designed to address a number of challenges:
- Flows from CSO’s are a very small portion of the larger Missouri River receiving waters being sampled.
- Trend detection is difficult because the hydrograph of the Missouri River within a year and between years is so variable.
- Contaminates can come from many upstream point and non-point sources which makes detecting what contaminates are coming from the Omaha area and which are coming from upstream sources hard.
- Simple grab samples do not represent the actual water quality of the river because the Missouri River is not well mixed.
Data Analysis
Data analysis now is beginning on the three and a half years of monitoring data collected so far. Information recorded during data collection such as local weather conditions, Missouri River conditions, days since last rain event, and amount of precipitation will be used to classify the data to understand how improvements to the CSO system has affected water quality.