Drinkability

From the second half of the 19th century, land reclamation has transformed the Sacramento-San Joaquin Delta (Delta). The landscape of the Delta has gone from a network of shifting waterways and tidal marshland to channels and islands fixed in position by hardened levees.

Regional Water Availability Assessments are scientific assessments of water availability in different hydrologic regions across the Nation. In the Delaware River Basin, the USGS will conduct a focused assessment of increasing freshwater salinity and an integrated and comprehensive assessment of multiple water quantity, quality and use factors.

The Proxies Project is a series of studies to improve our understanding of water contaminants and water quality hazards. These studies develop models and technical approaches for estimating concentrations and assessing risk associated with: - harmful algal blooms (HABs) - per- and polyfluoroalkyl substances (PFAS) - 12 elements of concern (EoC)

Wildfires pose a substantial risk to water supplies because they can lead to severe flooding, erosion, and delivery of sediment, nutrients, and metals to rivers, lakes, and reservoirs. The USGS works with federal and state land managers and local water providers to monitor and assess water quality after wildfires in order to help protect our Nation’s water resources.

Karst terrain is created from the dissolution of soluble rocks, principally limestone and dolomite. Karst areas are characterized by distinctive landforms (like springs, caves, sinkholes) and a unique hydrogeology that results in aquifers that are highly productive but extremely vulnerable to contamination.

The U.S. Geological Survey is integrating its water science programs to better address the Nation’s greatest water resource challenges. At the heart of this effort are plans to intensively study at least 10 Integrated Water Science (IWS) basins — medium-sized watersheds (10,000-20,000 square miles) and underlying aquifers — over the next decade. The IWS basins will represent a wide range of...

New projects from coast to coast will advance the research on harmful algal blooms (HABs) in lakes, reservoirs and rivers. The vivid emerald-colored algal blooms are caused by cyanobacteria, which can produce cyanotoxins that threaten human health and aquatic ecosystems and can cause major economic damage.

The Flaxville aquifer is present in the northern and central parts of the Fort Peck Indian Reservation and consists of sand and gravel that forms extensive plateaus and topographic benches used for dryland farming. Because many residents rely on groundwater as their primary water supply on the Reservation, the Flaxville and underlying aquifers are important sources of groundwater. The goal of this...

Our surface water, groundwater, and aquatic ecosystems are priceless resources, used by people across the Nation for drinking, irrigation, industry, and recreation. The National Water-Quality Assessment (NAWQA) Project is a leading source of scientific data and knowledge for development of science-based policies and management strategies to improve and protect our water resources.

Harmful algal blooms (HABs) are caused by a complex set of physical, chemical, biological, hydrological, and meteorological conditions. Many unanswered questions remain about occurrence, environmental triggers for toxicity, and the ability to predict the timing, duration, and toxicity of HABs.

Reliable drinking water is vital for the health and safety of all Americans. The USGS monitors and assesses the quality of the water used as a source for our nation's drinking water needs.

From chloride to corrosivity, from pesticides to PAHs, find the most recent National Water Quality Program (NWQP) science on these topics and effects on surface water, groundwater, and ecology. Informative web pages provide an overview and links to related web pages, publications, maps, news, and data.