CompassLive Science Shorts

Assessing Surface Water Quality in the Mississippi Delta

Forests and other ecosystems provide a key public health benefit in the form of plentiful, clean drinking water. SRS scientists examine how agriculture impacts surface water quality in the Mississippi River Delta. Photo courtesy of USGS.

USDA Forest Service scientists are measuring surface water quality in the Big Sunflower River watershed of the Mississippi Delta to better understand eutrophication of the Gulf of Mexico.

Extensive crop production contributes nutrients and suspended solids and leads to concerns about low dissolved oxygen and pathogens.

Ying Ouyang, Ted Leininger, and colleagues monitored water quality for several years at three study sites in the watershed.

“Some water quality measurements varied from year to year, but we saw little variation in pH and dissolved oxygen,” says Ouyang. “We found no trends in phosphorus, some seasonal trends in nitrogen concentrations, notably springtime peaks, but no annual increases.”

The researchers found a good correlation between measured magnesium and total dissolved solids – a useful proxy for estimating the latter in watersheds lacking those data.

Read the article in Water, Air, & Soil Pollution. For more information, email Ying Ouyang at