Skip to main content

Person

M Alisa Mast

thumbnail
Geospatial datasets were developed to estimate the altitude of the top of bedrock, altitude of the top of the Paradox salt, altitude of the water table in the alluvial aquifer, and the thickness and extent of saturated alluvium in the Paradox Valley in western Colorado. This study was completed by the U.S. Geological Survey (USGS) in cooperation with the Bureau of Reclamation for modeling of brine discharge to the Dolores River (Heywood and others, 2024; Paschke and others, 2024). One point dataset and 11 surfaces (shapefiles or rasters) are published in this data release. The point dataset (Paradox_well_data.zip) contains water-level and geologic data for groundwater, observation, test, and production wells in...
thumbnail
This data release includes raw and processed (inverted) data for three different geophysical methods, continuous resistivity profiles (CRP), direct current electrical resistivity tomography (ERT), and frequency domain electromagnetic induction (FDEM) data. These surface geophysical methods were used as a proxy for groundwater salinity in the Paradox Valley in western Colorado to investigate temporal and spatial variations in the position of brine-rich groundwater under the Dolores River. Continuous resistivity profile surveys along a 8-10 km reach of the Dolores River were conducted on March 7, May 16, and September 13 of 2017. The ERT surveys were conducted along 3 lines crossing the river and 1 line parallel to...
thumbnail
For the Western North America Mercury Synthesis, we compiled mercury records from 165 dated sediment cores from 138 natural lakes across western North America. Lake sediments are accepted as faithful recorders of historical mercury accumulation rates, and regional and sub-regional temporal and spatial trends were analyzed with descriptive and inferential statistics. Mercury accumulation rates in sediments have increased, on average, four times (4 ×) from 1850 to 2000 and continue to increase by approximately 0.2 μg/m2 per year. Lakes with the greatest increases were influenced by the Flin Flon smelter, followed by lakes directly affected by mining and wastewater discharges. Of lakes not directly affected by point...
Categories: Publication; Types: Citation
thumbnail
This data release includes GIS datasets supporting the Colorado Legacy Mine Lands Watershed Delineation and Scoring tool (WaDeS), a web mapping application available at https://geonarrative.usgs.gov/colmlwades/. Water chemistry data were compiled from the U.S. Geological Survey (USGS) National Water Information System (NWIS), U.S. Environmental Protection Agency (EPA) STORET database, and the USGS Central Colorado Assessment Project (CCAP) (Church and others, 2009). The CCAP study area was used for this application. Samples were summarized at each monitoring station and hardness-dependent chronic and acute toxicity thresholds for aquatic life protections under Colorado Regulation No. 31 (CDPHE, 5 CCR 1002-31) for...
thumbnail
This data release supports the following publication: Mast, M. A., 2018, Estimating metal concentrations with regression analysis and water-quality surrogates at nine sites on the Animas and San Juan Rivers, Colorado, New Mexico, and Utah: U.S. Geological Survey Scientific Investigations Report 2018-5116. The U.S. Geological Survey (USGS), in cooperation with the U. S. Environmental Protection Agency (EPA), developed site-specific regression models to estimate concentrations of selected metals at nine USGS streamflow-gaging stations along the Animas and San Juan Rivers. Multiple linear-regression models were developed by relating metal concentrations in discrete water-quality samples to continuously monitored streamflow...
View more...
ScienceBase brings together the best information it can find about USGS researchers and offices to show connections to publications, projects, and data. We are still working to improve this process and information is by no means complete. If you don't see everything you know is associated with you, a colleague, or your office, please be patient while we work to connect the dots. Feel free to contact sciencebase@usgs.gov.