Tyler Johnson (Former Employee)
Science and Products
Filter Total Items: 22
Data from Decadal Change in Groundwater Quality Web Site, 1988-2012 Data from Decadal Change in Groundwater Quality Web Site, 1988-2012
Groundwater quality data were collected in 5,000 wells between 1988-2001 by the National Water-Quality Assessment Project. About 1,500 of these wells were sampled again between 2002-2012 to evaluate decadal changes in groundwater quality. Monitoring wells, domestic supply wells, and some public supply wells were included in this study. All water was collected prior to treatment...
Location and population served by domestic wells in the conterminous U.S.: 1990 Location and population served by domestic wells in the conterminous U.S.: 1990
In this dataset we present two maps that estimate the location and population served by domestic wells in the contiguous United States. The first methodology, called the Block Group Method or BGM, builds upon the original block-group data from the 1990 census (the last time the U.S. Census queried the population regarding their source of water) by incorporating higher resolution census...
Classification of Chloride-to-Sulfate Mass Ratio for U.S. Groundwater With Respect to the Potential to Promote Galvanic Corrosion of Lead, 1991-2015; Water Well Data and Characteristic Values for States Classification of Chloride-to-Sulfate Mass Ratio for U.S. Groundwater With Respect to the Potential to Promote Galvanic Corrosion of Lead, 1991-2015; Water Well Data and Characteristic Values for States
Galvanic corrosion of lead in water distribution systems can occur when lead pipe or lead solder is in contact with a dissimilar metal such as copper. If the source water entering those systems has a relatively elevated chloride-to-sulfate mass ratio (CSMR), the potential for galvanic corrosion to occur is elevated (Gregory 1985; Edwards and Triantafyllidou, 2007), especially in water...
Langelier Saturation Indices Computed for U.S. Groundwater, 1991-2015; Water Well Data and Characteristic Values for States Langelier Saturation Indices Computed for U.S. Groundwater, 1991-2015; Water Well Data and Characteristic Values for States
The occurrence of metals, such as lead and copper, in household drinking supplies can often be a result of the corrosion of pipes and joints in water distribution systems. One measure of the potential for water to cause corrosion is the Langelier Saturation Index (LSI) (Langelier, 1936). The LSI is a measure of the potential for water to deposit a mineral layer (scale) within a water...
Filter Total Items: 27
Estimation of aquifer scale proportion using equal area grids: assessment of regional scale groundwater quality Estimation of aquifer scale proportion using equal area grids: assessment of regional scale groundwater quality
The proportion of an aquifer with constituent concentrations above a specified threshold (high concentrations) is taken as a nondimensional measure of regional scale water quality. If computed on the basis of area, it can be referred to as the aquifer scale proportion. A spatially unbiased estimate of aquifer scale proportion and a confidence interval for that estimate are obtained...
Authors
Kenneth Belitz, Bryant C. Jurgens, Matthew Landon, Miranda Fram, Tyler Johnson
Assigning land use to supply wells for the statistical characterization of regional groundwater quality: Correlating urban land use and VOC occurrence Assigning land use to supply wells for the statistical characterization of regional groundwater quality: Correlating urban land use and VOC occurrence
Many national and regional groundwater studies have correlated land use "near" a well, often using a 500 m radius circle, with water quality. However, the use of a 500 m circle may seem counterintuitive given that contributing areas are expected to extend up-gradient from wells, and not be circular in shape. The objective of this study was to evaluate if a 500 m circle is adequate for...
Authors
T.D. Johnson, K. Belitz
Evaluation of volatile organic compounds in two Mojave Desert basins-Mojave River and Antelope Valley-in San Bernardino, Los Angeles, and Kern Counties, California, June-October 2002 Evaluation of volatile organic compounds in two Mojave Desert basins-Mojave River and Antelope Valley-in San Bernardino, Los Angeles, and Kern Counties, California, June-October 2002
The California Aquifer Susceptibility Assessment of the Ground-Water Ambient Monitoring and Assessment Program was developed to assess water quality and susceptibility of ground-water resources to contamination from surficial sources. This study focuses on the Mojave River and the Antelope Valley ground-water basins in southern California. Volatile organic compound (VOC) data were...
Authors
Jill N. Densmore, Kenneth Belitz, Michael Wright, Barbara Dawson, Tyler Johnson
Occurrence and distribution of volatile organic compounds and pesticides in ground water in relation to hydrogeologic characteristics and land use in the Santa Ana basin, southern California Occurrence and distribution of volatile organic compounds and pesticides in ground water in relation to hydrogeologic characteristics and land use in the Santa Ana basin, southern California
This report presents an evaluation of the occurrence and distribution of VOCs and pesticides in the Santa Ana ground-water basins in relation to two types of explanatory factors: hydrogeologic characteristics and land use. The Santa Ana Basin is subdivided into the San Jacinto, the Inland, and the Coastal ground-water basins. Most wells sampled were deep and used for public supply. Data...
Authors
Scott Hamlin, Kenneth Belitz, Tyler Johnson
Assessing the susceptibility to contamination of two aquifer systems used for public water supply in the Modesto and Fresno metropolitan areas, California, 2001 and 2002 Assessing the susceptibility to contamination of two aquifer systems used for public water supply in the Modesto and Fresno metropolitan areas, California, 2001 and 2002
Ground-water samples were collected from 90 active public supply wells in the Fresno and Modesto metropolitan areas as part of the California Aquifer Susceptibility (CAS) program. The CAS program was formed to examine the susceptibility to contamination of aquifers that are tapped by public supply wells to serve the citizens of California. The objectives of the program are twofold: (1)...
Authors
Michael Wright, Kenneth Belitz, Tyler Johnson
Water Quality in the Santa Ana Basin, California, 1999-2001 Water Quality in the Santa Ana Basin, California, 1999-2001
This report contains the major findings of a 1999-2001 assessment of water quality in the Santa Ana River Basin. It is one of a series of reports by the National Water-Quality Assessment (NAWQA) Program that present major findings in 51 major river basins and aquifer systems across the Nation. In these reports, water quality is discussed in terms of local, State, and regional issues
Authors
Kenneth Belitz, Scott Hamlin, Carmen A. Burton, Robert Kent, Ronald Fay, Tyler Johnson
Science and Products
Filter Total Items: 22
Data from Decadal Change in Groundwater Quality Web Site, 1988-2012 Data from Decadal Change in Groundwater Quality Web Site, 1988-2012
Groundwater quality data were collected in 5,000 wells between 1988-2001 by the National Water-Quality Assessment Project. About 1,500 of these wells were sampled again between 2002-2012 to evaluate decadal changes in groundwater quality. Monitoring wells, domestic supply wells, and some public supply wells were included in this study. All water was collected prior to treatment...
Location and population served by domestic wells in the conterminous U.S.: 1990 Location and population served by domestic wells in the conterminous U.S.: 1990
In this dataset we present two maps that estimate the location and population served by domestic wells in the contiguous United States. The first methodology, called the Block Group Method or BGM, builds upon the original block-group data from the 1990 census (the last time the U.S. Census queried the population regarding their source of water) by incorporating higher resolution census...
Classification of Chloride-to-Sulfate Mass Ratio for U.S. Groundwater With Respect to the Potential to Promote Galvanic Corrosion of Lead, 1991-2015; Water Well Data and Characteristic Values for States Classification of Chloride-to-Sulfate Mass Ratio for U.S. Groundwater With Respect to the Potential to Promote Galvanic Corrosion of Lead, 1991-2015; Water Well Data and Characteristic Values for States
Galvanic corrosion of lead in water distribution systems can occur when lead pipe or lead solder is in contact with a dissimilar metal such as copper. If the source water entering those systems has a relatively elevated chloride-to-sulfate mass ratio (CSMR), the potential for galvanic corrosion to occur is elevated (Gregory 1985; Edwards and Triantafyllidou, 2007), especially in water...
Langelier Saturation Indices Computed for U.S. Groundwater, 1991-2015; Water Well Data and Characteristic Values for States Langelier Saturation Indices Computed for U.S. Groundwater, 1991-2015; Water Well Data and Characteristic Values for States
The occurrence of metals, such as lead and copper, in household drinking supplies can often be a result of the corrosion of pipes and joints in water distribution systems. One measure of the potential for water to cause corrosion is the Langelier Saturation Index (LSI) (Langelier, 1936). The LSI is a measure of the potential for water to deposit a mineral layer (scale) within a water...
Filter Total Items: 27
Estimation of aquifer scale proportion using equal area grids: assessment of regional scale groundwater quality Estimation of aquifer scale proportion using equal area grids: assessment of regional scale groundwater quality
The proportion of an aquifer with constituent concentrations above a specified threshold (high concentrations) is taken as a nondimensional measure of regional scale water quality. If computed on the basis of area, it can be referred to as the aquifer scale proportion. A spatially unbiased estimate of aquifer scale proportion and a confidence interval for that estimate are obtained...
Authors
Kenneth Belitz, Bryant C. Jurgens, Matthew Landon, Miranda Fram, Tyler Johnson
Assigning land use to supply wells for the statistical characterization of regional groundwater quality: Correlating urban land use and VOC occurrence Assigning land use to supply wells for the statistical characterization of regional groundwater quality: Correlating urban land use and VOC occurrence
Many national and regional groundwater studies have correlated land use "near" a well, often using a 500 m radius circle, with water quality. However, the use of a 500 m circle may seem counterintuitive given that contributing areas are expected to extend up-gradient from wells, and not be circular in shape. The objective of this study was to evaluate if a 500 m circle is adequate for...
Authors
T.D. Johnson, K. Belitz
Evaluation of volatile organic compounds in two Mojave Desert basins-Mojave River and Antelope Valley-in San Bernardino, Los Angeles, and Kern Counties, California, June-October 2002 Evaluation of volatile organic compounds in two Mojave Desert basins-Mojave River and Antelope Valley-in San Bernardino, Los Angeles, and Kern Counties, California, June-October 2002
The California Aquifer Susceptibility Assessment of the Ground-Water Ambient Monitoring and Assessment Program was developed to assess water quality and susceptibility of ground-water resources to contamination from surficial sources. This study focuses on the Mojave River and the Antelope Valley ground-water basins in southern California. Volatile organic compound (VOC) data were...
Authors
Jill N. Densmore, Kenneth Belitz, Michael Wright, Barbara Dawson, Tyler Johnson
Occurrence and distribution of volatile organic compounds and pesticides in ground water in relation to hydrogeologic characteristics and land use in the Santa Ana basin, southern California Occurrence and distribution of volatile organic compounds and pesticides in ground water in relation to hydrogeologic characteristics and land use in the Santa Ana basin, southern California
This report presents an evaluation of the occurrence and distribution of VOCs and pesticides in the Santa Ana ground-water basins in relation to two types of explanatory factors: hydrogeologic characteristics and land use. The Santa Ana Basin is subdivided into the San Jacinto, the Inland, and the Coastal ground-water basins. Most wells sampled were deep and used for public supply. Data...
Authors
Scott Hamlin, Kenneth Belitz, Tyler Johnson
Assessing the susceptibility to contamination of two aquifer systems used for public water supply in the Modesto and Fresno metropolitan areas, California, 2001 and 2002 Assessing the susceptibility to contamination of two aquifer systems used for public water supply in the Modesto and Fresno metropolitan areas, California, 2001 and 2002
Ground-water samples were collected from 90 active public supply wells in the Fresno and Modesto metropolitan areas as part of the California Aquifer Susceptibility (CAS) program. The CAS program was formed to examine the susceptibility to contamination of aquifers that are tapped by public supply wells to serve the citizens of California. The objectives of the program are twofold: (1)...
Authors
Michael Wright, Kenneth Belitz, Tyler Johnson
Water Quality in the Santa Ana Basin, California, 1999-2001 Water Quality in the Santa Ana Basin, California, 1999-2001
This report contains the major findings of a 1999-2001 assessment of water quality in the Santa Ana River Basin. It is one of a series of reports by the National Water-Quality Assessment (NAWQA) Program that present major findings in 51 major river basins and aquifer systems across the Nation. In these reports, water quality is discussed in terms of local, State, and regional issues
Authors
Kenneth Belitz, Scott Hamlin, Carmen A. Burton, Robert Kent, Ronald Fay, Tyler Johnson