Water Quality

A water budget is an accounting of hydrologic components of the water cycle, transfers between the components, and their relative contributions within a water system. Water budgets help define how much water is available, how much water is used, where the water comes from, and at what rate water is replenished or consumed. In its simplest form, a water budget defines the amount of water entering...

Coal-tar-based pavement sealant is a potent source of polycyclic aromatic hydrocarbons (PAHs), as documented by the USGS and other researchers. Coal-tar-based sealcoat products typically are 20 to 35% coal tar or coal-tar pitch—these materials are known human carcinogens that contain high concentrations of PAHs and related chemicals. Coal-tar-based pavement sealcoat typically contains 35,000 to...

The U.S. Environmental Protection Agency (EPA) has identified sediment as a leading cause of impairment in the Nation’s rivers and streams. Excessive sedimentation degrades aquatic habitat; reduces longevity of water-supply, flood-control reservoirs; and is the primary transport mechanism of toxic organic chemicals, heavy metals, and nutrients. The USGS Oklahoma-Texas Water Science Center (OTWSC)...

The USGS Oklahoma-Texas Water Science Center (OTWSC) researches nutrients by analyzing water samples and habitats across the State. Information about the occurrence and abundance of nutrients is critical for understanding and maintaining water resources across Texas. Visit the links below for more information on our data and science.

The zebra mussel is an invasive species that has spread rapidly in the United States. The first confirmed detection of zebra mussels in Texas occurred in 2009 at Lake Texoma along the Texas–Oklahoma border. The USGS Zebra Mussel Monitoring Program for Texas (ZMMP) began in April 2010 and has expanded over time in response to the continued spread of zebra mussels in Texas.

Many types of algae can cause HABs in freshwater ecosystems. The most frequent and severe blooms typically are caused by cyanobacteria, the only freshwater “algae” with the potential for production of toxins that can adversely affect human health. USGS Oklahoma-Texas Water Science Center (OTWSC) scientists studying HAB issues in water bodies throughout the United States, using a combination of...

Water chemistry studies allow USGS Oklahoma-Texas Water Science Center (OTWSC) scientists to look at what has been dissolved in the water, how different constituents in water may react together, and how constituents in water interact with the minerals along its flow path. Visit the links below for more information on our data and science.

Contamination is the degradation of water quality compared to its original or natural conditions. USGS Oklahoma-Texas Water Science Center (OTWSC) scientists have been part of several projects to quantify the presence and effects of contaminants in surface water, groundwater, and sediment across Texas. OTWSC scientists also have looked at specific contaminant issues, such as establishing baseline...