Pollution (Chemical and Biological)

Atmospheric nitrogen deposition, climate change and recreation are rapidly altering high elevation ecosystems. This project will evaluate long-term biogeochemical, hydrological, and ecological trends in Rocky Mountain National Park to understand the causes and rates of change in alpine and subalpine waters, soils, and vegetation. Policy makers and resource managers of high-elevation, protected...

The National Atmospheric Deposition Program (NADP) is a collaboration of atmospheric monitoring networks. The purpose of the networks is to collect data to evaluate air quality. Network data also inform science-based actions to protect human health and preserve ecosystems for current and future generations. The NADP National Trends Network (NTN) quantifies the concentration of eight major ions and...

The Willamette River Basin reflects the conflicting water demands between humans and ecosystems—particularly salmon— and the challenge resource managers face throughout the Pacific Northwest.

How does the water quality measure up? It all depends on what the water will be used for and what contaminants are of interest. Water-quality benchmarks are designed to protect drinking water, recreation, aquatic life, and wildlife. Here you’ll find links to some of the most widely used sets of water, sediment, and fish tissue benchmarks and general guidance about their interpretation.

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 Upper Colorado River Basin, the USGS will conduct a focused assessment of how snowpack and snowmelt influence hydrology and water quality, and an integrated and comprehensive assessment of multiple water quantity, quality and use factors.

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.

In 2019, the USGS began a water-quality monitoring program in Lake Koocanusa (also known as Koocanusa Reservoir) and at a site on the Kootenai River downstream of Libby Dam to provide high-frequency water-quality data for Federal, State, Provincial, and Tribal entities in the United States and Canada.

MODFLOW is the USGS's modular hydrologic model. MODFLOW is considered an international standard for simulating and predicting groundwater conditions and groundwater/surface-water interactions. MODFLOW 6 is presently the core MODFLOW version distributed by the USGS. The previous core version, MODFLOW-2005, is actively maintained and supported as well.

The Delta of the Sacramento and San Joaquin rivers provides drinking water supplies to two-thirds of Californians, and is a fragile ecosystem home to threatened and endangered species. The CASCaDE project builds on several decades of USGS science to address the goals of achieving water supply reliability and restoring the ecosystems in the Bay-Delta system.