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At least 433 records · Page 24Linked to original sources
USGS2014

Delineation of marsh types of the Texas coast from Corpus Christi Bay to the Sabine River in 2010

Coastal zone managers and researchers often require detailed information regarding emergent marsh vegetation types for modeling habitat capacities and needs of marsh-reliant wildlife (such as waterfowl and alligator). Detailed information on the extent and distribution of marsh vegetation zones throughout the Texas coast has been historically unavailable. In response, the U.S. Geological Survey, in cooperation and collaboration with the U.S. Fish and Wildlife Service via the Gulf Coast Joint Venture, Texas A&M University-Kingsville, the University of Louisiana-Lafayette, and Ducks Unlimited, Inc., has produced a classification of marsh vegetation types along the middle and upper Texas coast from Corpus Christi Bay to the Sabine River. This study incorporates approximately 1,000 ground reference locations collected via helicopter surveys in coastal marsh areas and about 2,000 supplemental locations from fresh marsh, water, and “other” (that is, nonmarsh) areas. About two-thirds of these data were used for training, and about one-third were used for assessing accuracy. Decision-tree analyses using Rulequest See5 were used to classify emergent marsh vegetation types by using these data, multitemporal satellite-based multispectral imagery from 2009 to 2011, a bare-earth digital elevation model (DEM) based on airborne light detection and ranging (lidar), alternative contemporary land cover classifications, and other spatially explicit variables believed to be important for delineating the extent and distribution of marsh vegetation communities. Image objects were generated from segmentation of high-resolution airborne imagery acquired in 2010 and were used to refine the classification. The classification is dated 2010 because the year is both the midpoint of the multitemporal satellite-based imagery (2009–11) classified and the date of the high-resolution airborne imagery that was used to develop image objects. Overall accuracy corrected for bias (accuracy estimate incorporates true marginal proportions) was 91 percent (95 percent confidence interval [CI]: 89.2–92.8), with a kappa statistic of 0.79 (95 percent CI: 0.77–0.81). The classification performed best for saline marsh (user’s accuracy 81.5 percent; producer’s accuracy corrected for bias 62.9 percent) but showed a lesser ability to discriminate intermediate marsh (user’s accuracy 47.7 percent; producer’s accuracy corrected for bias 49.5 percent). Because of confusion in intermediate and brackish marsh classes, an alternative classification containing only three marsh types was created in which intermediate and brackish marshes were combined into a single class. Image objects were reattributed by using this alternative three-marsh-type classification. Overall accuracy, corrected for bias, of this more general classification was 92.4 percent (95 percent CI: 90.7–94.2), and the kappa statistic was 0.83 (95 percent CI: 0.81–0.85). Mean user’s accuracy for marshes within the four-marsh-type and three-marsh-type classifications was 65.4 percent and 75.6 percent, respectively, whereas mean producer’s accuracy was 56.7 percent and 65.1 percent, respectively. This study provides a more objective and repeatable method for classifying marsh types of the middle and upper Texas coast at an extent and greater level of detail than previously available for the study area. The seamless classification produced through this work is now available to help State agencies (such as the Texas Parks and Wildlife Department) and landscape-scale conservation partnerships (such as the Gulf Coast Prairie Landscape Conservation Cooperative and the Gulf Coast Joint Venture) to develop and (or) refine conservation plans targeting priority natural resources. Moreover, these data may improve projections of landscape change and serve as a baseline for monitoring future changes resulting from chronic and episodic stressors.

Texas↗
USGS2021

Estimating invertebrate response to changes in total nitrogen, total phosphorus, and specific conductance at sites where invertebrate data are unavailable

The purpose of this report is to describe a possible approach to estimate changes in invertebrate taxa richness at sites with known water-quality trends but no invertebrate data. In this study, data from 1,322 sites were used to describe invertebrate response to changes in total nitrogen, total phosphorus, or specific conductance, and to estimate changes in invertebrate taxa richness at 259 sites with reported water-quality trends but no invertebrate data. Sites were stratified using propensity score analysis to control for confounding factors (for example, climate, land use, land cover). Generalized linear models were developed to describe changes in invertebrate taxa richness along gradients of total nitrogen, total phosphorus, and specific conductance values. The magnitude and direction of invertebrate response to gradients of water quality varied among parameters and strata, with changes in invertebrate taxa richness per natural log unit change in concentration ranging from –7 to +6. However, estimated changes in invertebrate taxa richness at sites with known water-quality trends were much less and did not exceed three taxa until changes in concentration were greater than 50 percent. Applying this approach provides (1) a first screening to identify where changes in invertebrate taxa richness are likely to occur and (2) the necessary groundwork to improve estimation of invertebrate response to trends in water quality where biological data are lacking.

Scientific Investigations Report↗
USGS2005

Framework for regional synthesis of water-quality data for the glacial aquifer system in the United States

The glacial aquifer system is the largest principal aquifer in aerial extent and ground-water use for public supply in the United States. A principal aquifer is defined as a regionally extensive aquifer or aquifer system that has the potential to be used as a source of potable water (U.S. Geological Survey, 2003). Multiple aquifers often are grouped into large, extensive aquifer systems such as the glacial aquifer system. The glacial aquifer system is considered here to include all unconsolidated aquifers above bedrock north of the line of continental glaciation throughout the country (fig. 1). Total withdrawals from the glacial aquifer system were 3,560 million gallons per day in 2000, which constitutes almost 5 percent of total withdrawals from all aquifers in the United States (Maupin and Barber, 2005). Approximately 41 million people relied on the glacial aquifer for public supply and domestic use in 2000. The U.S. Geological Survey National Water-Quality Assessment (NAWQA) Program began assessing the glacial aquifer system in 1991. The assessment of water-quality data on a regional scale, such as the glacial aquifer system, is coincident with the regional framework established by the Regional Aquifer-System Analysis Program (RASA) (Sun and others, 1997). From 1978 to 1995, the RASA Program systematically evaluated 25 of the Nation's most important groundwater systems including studies in the glacial aquifer system in the northeast, Midwest, and northern Midwest United States. The NAWQA Program is building on the work of the RASA Program to study the water quality of 16 of the most important ground-water systems (Lapham and others, 2005). Over 1,700 water-quality samples have been collected by the NAWQA Program from 1991 to 2004 to assess the glacial aquifer system. This large data set is unique in that the samples have been collected using a consistent sampling protocol, and multiple nested samples. The nested samples address the recently recharged shallow ground water, deeper water from principal aquifers often used for domestic supply, and source water used for public supplies within the glacial aquifer system. Information concerning the NAWQA Program including study unit boundaries is shown in figure 1 (Lapham and others, 2005). A framework for comparison of water quality across the glacial aquifer system has been developed based on two primary characteristics: intrinsic susceptibility and vulnerability. Intrinsic susceptibility, which is a measure of the ease at which water enters and moves through aquifer material, is a characteristic of the aquifer and overlying material and of the hydrologic conditions. Intrinsic susceptibility is independent of the chemical characteristics of the contaminant and its sources. In this way, intrinsic susceptibility assessments do not target specific natural or anthropogenic sources of contamination but instead consider only the physical factors affecting the flow of water to, and through the ground-water resource (Focazio and others, 2002). On a regional scale, intrinsic susceptibility is represented by the spatial distribution of fine- or coarse-grained material at the land surface, and the physical setting of the aquifer system. Vulnerability, which is a function of both intrinsic susceptibility and the proximity and characteristics of contaminant sources, includes consideration of features related to anthropogenic sources of contaminants, such as the character of the upgradient land use (for example, urban, agricultural, undeveloped, and others); as well as features related to natural sources of contaminants, such as the mineralogy of the aquifer material or the geochemical conditions within the aquifer system. The framework helps categorize this large region into areas of similar hydrogeologic characteristics for which water quality can be compared. The purpose of this report is to describe this framework and how it will be used for regional synthesis of water-quality da

Scientific Investigations Report↗
USGS2014

Water quality at a biosolids-application area near Deer Trail, Colorado, 1993-1999

The Metro Wastewater Reclamation District (Metro District) in Denver, Colo., applied biosolids resulting from municipal sewage treatment to farmland in eastern Colorado beginning in December 1993. In mid-1993, the U.S. Geological Survey in cooperation with the Metro District began monitoring water quality at the biosolids-application area about 10 miles east of Deer Trail, Colo., to evaluate baseline water quality and the combined effects of natural processes, land uses, and biosolids applications on water quality of the biosolids application area. Water quality was characterized by baseline and post-biosolids-application sampling for selected inorganic and bacteriological constituents during 1993 through 1998, with some additional specialized sampling in 1999. The study included limited sampling of surface water and the unsaturated zone, but primarily focused on groundwater. See report for complete abstract.

Colorado↗
USGS2026

Investigation of fish communities in natural channel sections of the Mohawk River, New York

Little is known about the natural resources in the natural channel sections of the Mohawk River between Rome and Frankfort, New York, where the river channel runs separately from and parallel to the Erie Canal. This river section runs through multiple locations that are listed as active remediation sites under New York’s Inactive Hazardous Waste Disposal Site Program and has negligible public or commercial access. As a result, there is minimal recreational usage of this river section, and efforts to conduct biological sampling have been limited. To better understand the composition of fish communities and contaminant concentrations in the natural channel of the Mohawk River, the U.S. Geological Survey, in cooperation with the New York State Department of Environmental Conservation, sampled resident fish in the 34-kilometer section from the mouth of Oriskany Creek downstream to Frankfort. Fish communities were sampled using boat electrofishing during 2021, 2023, and 2024 across multiple reaches within this section. These data were used to estimate species richness (number of species), relative abundance and biomass (catch rates), population size structure (distribution of lengths), and fish condition (a proxy for health). Some gamefish specimens were also analyzed to determine contaminant concentrations in fish tissue. A total of 1,531 individual fish and 38 fish species were captured across all surveys. Seventeen of the 38 (45 percent) species were classified as native to the Mohawk River watershed, whereas 21 of the 38 (55 percent) species were classified as nonnative. Some popular gamefish species such as largemouth bass ( Micropterus salmoides ) and smallmouth bass ( Micropterus dolomieu ) were abundant in most reaches, whereas others such as walleye ( Sander vitreus ) and northern pike ( Esox lucius ) were found sporadically. Only one round goby ( Neogobius melanostomus ) was captured, indicating that this high-profile invasive species remains uncommon in this habitat. A backwater reach had the greatest relative abundance and condition of many species. This indicates connected lentic habitats such as oxbows and backwaters may be important nursery and refuge areas in the aquatic ecosystem. Polychlorinated biphenyl (PCB) concentrations in fish tissue were highly elevated relative to the New York State Department of Health (NYSDOH) fish consumption “don’t eat” advisory guideline. Some specimens exceeded the guideline by an order of magnitude or more, particularly those from a localized area downstream from the Utica Harbor Dam. Concentrations of perfluorooctanesulfonic acid (PFOS) often approached the NYSDOH “don’t eat” consumption guideline but only one sample exceeded the guideline. Concentrations of other contaminants such as mercury and pesticides were consistently measured at less than the “don’t eat” consumption guidelines. These data indicate PCBs remain the primary contaminant of concern in the natural channel of the Mohawk River and are readily bioaccumulating in aquatic organisms despite prior remediation measures. Taken together, the findings in this report are intended to inform future decisions related to fisheries management, public access, recreational usage, and fish consumption advisories.

New York↗
USGS2006

Effects of urbanization on stream ecosystems in the South Platte River basin, Colorado and Wyoming

This report describes the effects of urbanization on physical, chemical, and biological characteristics of stream ecosystems in 28 basins along an urban land-use gradient in the South Platte River Basin, Colorado and Wyoming, from 2002 through 2003. Study basins were chosen to minimize natural variability among basins due to factors such as geology, elevation, and climate and to maximize coverage of different stages of urban development among basins. Because land use or population density alone often are not a complete measure of urbanization, land use, land cover, infrastructure, and socioeconomic variables were integrated in a multimetric urban intensity index to represent the degree of urban development in each study basin. Physical characteristics studied included stream hydrology, stream temperature, and habitat; chemical characteristics studied included nutrients, pesticides, suspended sediment, sulfate, chloride, and fecal bacteria concentrations; and biological characteristics studied included algae, fish, and invertebrate communities. Semipermeable membrane devices (SPMDs), passive samplers that concentrate trace levels of hydrophobic organic contaminants like polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs), also were used. The objectives of the study were to (1) examine physical, chemical, and biological responses along the gradient of urbanization; (2) determine the major physical, chemical, and landscape variables affecting the structure of aquatic communities; and (3) evaluate the relevance of the results to the management of water resources in the South Platte River Basin. Commonly observed effects of urbanization on instream physical, chemical, and biological characteristics, such as increased flashiness, higher magnitude and more frequent peak flows, increased concentrations of chemicals, and changes in aquatic community structure, generally were not observed in this study. None of the hydrologic, temperature, habitat, or chemical variables were correlated strongly (Spearman's rho greater than or equal to 0.7) with urban intensity, with the exception of some of the SPMD-based toxicity and chemical variables. SPMD-based measures of potential toxicity and PAH concentrations were positively correlated with urban intensity. The PAH concentrations also were positively correlated with measures of road density and negatively correlated with distance to the nearest road, indicating that automobile exhaust is a major source of these compounds in the study area. This source may be localized enough that the transport of PAHs would be minimally affected by water-management practices such as diversion or storage upstream. In contrast, the predominant sources of nutrients, bacteria, suspended sediment, sulfate, chloride, and pesticides may be more dispersed throughout the drainage area and, therefore, their transport to downstream sites may be subject to greater disruption by water regulation. Although no direct link was found between most water-chemistry characteristics and urbanization, invertebrate, algae, and fish-community characteristics were strongly associated with nutrients, pesticides, sulfate, chloride, and suspended sediment. None of the biological community variables were strongly correlated with the urban intensity index. Algal biomass predominantly was associated with total nitrogen concentrations, nitrite-plus-nitrate concentrations, and the duration of high flows. Fish communities predominantly were associated with housing age, the percentage of suspended sediment finer than 0.063 millimeters and chloride concentrations. Invertebrate communities predominantly were associated with the frequency of rising and falling flow events, the duration of high flows, total nitrogen concentrations, nitrite-plus-nitrate concentrations, and total herbicide concentrations. Historical records indicate that aquatic communities in the region may have been altered prior to any substantial urban development by early agricultural and water-management practices. Present-day aquatic communities are composed primarily of tolerant species even in areas of minimal urban development; when development does occur, the communities already may be resistant to disturbance. In addition to the effects of historical stressors on aquatic community structure, it is possible that current water-management practices in the study basins are having an effect. In the absence of natural, unaltered hydrologic conditions, more sensitive taxa may be unable to recolonize urban streams. The movement and storage of water also may lead to a disconnect between the land surface and streams, resulting in instream physical, chemical, and biological characteristics that, to some degree, are independent of land-cover characteristics.

Colorado, Wyoming↗
USGS2018

Surface-water quality in the Lycoming Creek watershed, north-central Pennsylvania, August 1–3, 2011

This report presents the methodology and results for a study of surface-water quality of the Lycoming Creek watershed in north-central Pennsylvania during August 1–3, 2011. The study was done in cooperation with the Williamsport Municipal Water Authority and the Pennsylvania Department of Environmental Protection. Samples of stream water were collected from 31 sites in an area of exploration and production of natural gas from the Marcellus Shale – 5 sites on the main stem of Lycoming Creek and 26 sites on tributary streams. The samples provide a snapshot of the base-flow water-quality conditions, which helps document the spatial variability in water-quality and could be useful for assessing future changes. The 272-square mile Lycoming Creek watershed is located within Lycoming, Tioga, and Sullivan Counties in north-central Pennsylvania. Lycoming Creek flows 37.5 miles to its confluence with the West Branch Susquehanna River in the city of Williamsport. A well field that supplies water for Williamsport captures some water that has infiltrated the streambed of Lycoming Creek. Because the stream provides a source of water to the well field, this study focused on the stream-water quality as it relates to drinking-water standards as opposed to aquatic life. Surface-water samples collected at 20 sites by the U.S. Geological Survey and 11 sites by the Pennsylvania Department of Environmental Protection were analyzed by each agency for a suite of constituents that included major ions, trace metals, nutrients, and radiochemicals. None of the analytical results failed to meet standards set by the U.S. Environmental Protection Agency as maximum contaminant levels for drinking water. Results of the sampling show the substantial spatial variability in base-flow water quality within the Lycoming Creek watershed caused by the interrelated effects of physiography, geology and land use. Dissolved-solids concentrations ranged from less than the laboratory reporting level of 12 milligrams per liter (mg/L) in Wolf Run, a pristine forested watershed, to 202 mg/L in Bottle Run, a watershed with more development near Williamsport. Concentrations of the major ions ranged over at least one order of magnitude; chloride had the largest range from 0.3 to 45.4 mg/L, with nine samples exceeding the natural background level of about 5 mg/L, most likely because of the application of deicing salt to roads. Trace constituents were even more variable, with concentrations for aluminum, cobalt, and manganese ranging over almost four orders of magnitude. Samples from Red Run and Dutchman Run, watersheds that experienced past coal mining activity, had concentrations of 11 metals that were significantly greater than in samples collected from other streams. Samples from Bottle Run, the tributary of Lycoming Creek nearest to Williamsport, contained elevated levels of chloride and boron, constituents associated with urban development.

Pennsylvania↗
USGS2008

Geologic resource evaluation of Kaloko-Honokohau National Historical Park, Hawai'i: Geology and coastal landforms

Geologic resource inventories of lands managed by the National Park Service (NPS) are important products for the parks and are designed to provide scientific information to better manage park resources. Park-specific geologic reports are used to identify geologic features and processes that are relevant to park ecosystems, evaluate the impact of human activities on geologic features and processes, identify geologic research and monitoring needs, and enhance opportunities for education and interpretation. These geologic reports are planned to provide a brief geologic history of the park and address specific geologic issues that link the park geology and the resource manager. The Kona coast National Parks of the Island of Hawai'i are intended to preserve the natural beauty of the Kona coast and protect significant ancient structures and artifacts of the native Hawaiians. Pu'ukohola Heiau National Historic Site (PUHE), Kaloko-Honokohau National Historical Park (KAHO), and Pu'uhonua O Honaunau National Historical Park (PUHO) are three Kona parks studied by the U.S. Geological Survey (USGS) Coastal and Marine Geology Team in cooperation with the National Park Service. This report is one of six related reports designed to provide geologic and benthic-habitat information for the three Kona parks. Each geology and coastal-landform report describes the regional geologic setting of the Hawaiian Islands, gives a general description of the geology of the Kona coast, and presents the geologic setting and issues for one of the parks. The related benthic-habitat mapping reports discuss the marine data and habitat classification scheme, and present results of the mapping program. Kaloko-Honokohau National Historical Park (KAHO) was established in 1978 in order to preserve and protect traditional native Hawaiian culture and cultural sites. The park is the site of an ancient Hawaiian settlement, occupies 469 ha and is considered a locale of considerable cultural and historical significance. Cultural resources include fishponds, petroglyphs and a heiau (religious site). The fishponds are also recognized as exceptional birding areas and are important wetlands for migratory birds. The ocean and reef have been designated as a Marine Area Reserve, where green sea turtles commonly come ashore to rest. The park is also a valuable recreational resource, with approximately 4 km of coastline and a protective cove ideal for snorkeling and swimming. KAHO park boundaries extend beyond the mean high tide line and include the adjacent marine environment. An accompanying report for KAHO presents the results of benthic habitat mapping of the offshore waters, from the shoreline to approximately 40 m water depth. Ground-water quality and potential downslope impacts created by development around the park are of concern to Park management.

Hawaii↗
USGS2009

Geomorphic segmentation, hydraulic geometry, and hydraulic microhabitats of the Niobrara River, Nebraska — Methods and initial results

The Niobrara River of Nebraska is a geologically, ecologically, and economically significant resource. The State of Nebraska has recognized the need to better manage the surface- and ground-water resources of the Niobrara River so they are sustainable in the long term. In cooperation with the Nebraska Game and Parks Commission, the U.S. Geological Survey is investigating the hydrogeomorphic settings and hydraulic geometry of the Niobrara River to assist in characterizing the types of broad-scale physical habitat attributes that may be of importance to the ecological resources of the river system. This report includes an inventory of surface-water and ground-water hydrology data, surface water-quality data, a longitudinal geomorphic segmentation and characterization of the main channel and its valley, and hydraulic geometry relations for the 330-mile section of the Niobrara River from Dunlap Diversion Dam in western Nebraska to the Missouri River confluence. Hydraulic microhabitats also were analyzed using available data from discharge measurements to demonstrate the potential application of these data and analysis methods. The main channel of the Niobrara was partitioned into three distinct fluvial geomorphic provinces: an upper province characterized by open valleys and a sinuous, equiwidth channel; a central province characterized by mixed valley and channel settings, including several entrenched canyon reaches; and a lower province where the valley is wide, yet restricted, but the river also is wide and persistently braided. Within the three fluvial geomorphic provinces, 36 geomorphic segments were identified using a customized, process-orientated classification scheme, which described the basic physical characteristics of the Niobrara River and its valley. Analysis of the longitudinal slope characteristics indicated that the Niobrara River longitudinal profile may be largely bedrock-controlled, with slope inflections co-located at changes in bedrock type at river level. Hydraulic geometry relations indicated that local (at-a-station) channel adjustments of the Niobrara River to changing discharge are accommodated mainly by changes in velocity, and streamwise adjustments are accommodated through changes in channel width. Downstream hydraulic geometry relations are in general agreement with values previously published for rivers of the Great Plains, but coefficients are likely skewed low because the locations of the streamflow-gaging stations used in this analysis are located at natural or engineered constrictions and may not be accurately representing downstream adjustment processes of the Niobrara River. A demonstration analysis of hydraulic microhabitat attributes at a single station indicated that changes in velocity-related habitat types is the primary microhabitat adjustment over a range of discharges, but the magnitude of that adjustment for any particular discharge is temporally variable.

Nebraska↗
USGS2010

Status and understanding of groundwater quality in the central-eastside San Joaquin Basin, 2006: California GAMA Priority Basin Project

Groundwater quality in the approximately 1,695-square-mile Central Eastside San Joaquin Basin (Central Eastside) study unit was investigated as part of the Priority Basin Project (PBP) of the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The GAMA PBP was developed in response to the California Groundwater Quality Monitoring Act of 2001, and is being conducted by the California State Water Resources Control Board in collaboration with the U.S. Geological Survey and the Lawrence Livermore National Laboratory. The GAMA Central Eastside study unit was designed to provide a spatially unbiased assessment of untreated-groundwater quality, as well as a statistically consistent basis for comparing water quality throughout California. During March through June 2006, samples were collected from 78 wells in Stanislaus and Merced Counties, 58 of which were selected using a spatially distributed, randomized grid-based method to provide statistical representation of the study unit (grid wells), and 20 of which were sampled to evaluate changes in water chemistry along groundwater-flow paths (understanding wells). Water-quality data from the California Department of Public Health (CDPH) database also were used for the assessment. An assessment of the current status of the groundwater quality included collecting samples from wells for analysis of anthropogenic constituents such as volatile organic compounds (VOCs) and pesticides, as well as naturally occurring constituents such as major ions and trace elements. The assessment of status is intended to characterize the quality of untreated-groundwater resources within the primary aquifer system, not the treated drinking water delivered to consumers by water purveyors. The primary aquifer system (hereinafter, primary aquifer) is defined as that part of the aquifer corresponding to the perforation interval of wells listed in the CDPH database for the Central Eastside study unit. The quality of groundwater in shallower or deeper water-bearing zones may differ from that in the primary aquifer; shallower groundwater may be more vulnerable to surficial contamination. The primary aquifer is represented by the grid wells, of which 90 percent had depths to the tops of their perforations of about 80 to 330 feet and depths to bottom of about 100 to 670 feet. Relative-concentrations (sample concentration divided by benchmark concentration) were used as the primary metric for assessing the status of water quality for those constituents that have Federal and (or) California human health or aesthetic benchmarks. A relative-concentration greater than (>) 1.0 indicates a concentration above a benchmark, and less than or equal to (≤) 1.0 indicates a concentration equal to or below a benchmark. For organic and special interest constituents, relative-concentrations were classified as high (>1.0), moderate (≤1.0 and >0.1), or low (≤0.1). For inorganic constituents, relative-concentrations were classified as high (>1.0), moderate (≤1.0 and >0.5), or low (≤0.5). The threshold between low and moderate classifications was lower for organic and special interest constituents than for inorganic constituents because organic constituents generally are less prevalent and have smaller relative-concentrations than inorganic constituents. Grid-based and spatially-weighted approaches, the latter incorporating data from all CDPH wells, were used to evaluate the proportion of the primary aquifer (aquifer-scale proportions) with high, moderate, or low relative-concentrations. For individual constituents or classes of constituents, the aquifer-scale high proportion is the percentage of the area of the study unit having high relative-concentrations within the depth-zones of the primary aquifer. Aquifer-scale moderate and low proportions are defined similarly. Spatially-weighted aquifer-scale high proportions nearly always fell within the 90-percent confidence interval of grid-based aquifer-scale high proportions, indicating that the grid-based approach yielded statistically equivalent results to the spatially-weighted approach incorporating CDPH data. The status assessment for inorganic constituents showed that inorganic constituents (one or more) were high, relative to human-health benchmarks, in 18.0 percent of the primary aquifer, moderate in 44.0 percent, and low in 38.0 percent. Of inorganic constituents with human-health benchmarks, arsenic, vanadium, and nitrate were detected at high relative-concentrations in 15.6 percent, 3.6 percent, and 2.1 percent, respectively, of the primary aquifer. Of inorganic constituents with secondary maximum contaminant levels (SMCL), manganese, iron, and TDS were detected at high relative-concentrations in 4.5 percent, 2.2 percent, and 1.7 percent, respectively, of the primary aquifer. The status assessment for organic constituents showed that organic constituents (one or more) were high, relative to human-health benchmarks, in a smaller proportion of the primary aquifer (1.2 percent) than inorganic constituents (18.0 percent). Organic constituents had moderate relative-concentrations in 14.3 percent, and had low relative-concentrations or were not detected in 84.5 percent, of the primary aquifer. The proportion of the primary aquifer with high relative-concentrations of organic constituents reflected high proportions of the discontinued soil fumigant 1,2-dibromo-3-chlororopane (DBCP; 1.0 percent) and the solvent tetrachloroethene (PCE; 0.2 percent). Most of the organic and special interest constituents detected in groundwater in the Central Eastside study unit have human-health benchmarks. Of the 205 organic and special interest constituents analyzed for, 36 constituents were detected. Of these constituents, 32 were detected only at low relative-concentrations. Four constituents, chloroform, carbon tetrachloride, DBCP, and perchlorate, were detected at moderate relative-concentrations in grid wells. Nine organic and special-interest constituents were detected frequently (detected in greater than 10 percent of samples): the trihalomethanes chloroform, bromoform, bromodichloromethane, and dibromochloromethane; the solvent PCE; the herbicides atrazine, simazine, and metolachlor, and special-interest constituent perchlorate. An assessment of understanding of the groundwater quality included sampling of understanding wells, some of which were perforated in shallower or deeper portions of the aquifer system than the primary aquifer, and analysis of correlations of groundwater quality with land use, depth, age classification, and other potential explanatory factors. The understanding assessment indicated that the concentrations of many constituents were related to depth and groundwater age. However, concentrations of individual constituents or constituent classes also were sometimes related to geochemical conditions, lateral position in the flow system, or land use. High and moderate relative-concentrations of uranium, nitrate, and total dissolved solids (TDS) were detected in some wells where the tops of perforations are within the upper 200 feet of the aquifer system. In wells with the depth to the top of perforations below this depth, concentrations were low. A similar pattern occurred for the sum of herbicide concentrations. These vertical water-chemistry patterns are consistent with the hydrogeologic setting, in which return flows from agricultural and urban land use are the major source of recharge, and withdrawals for irrigation and urban supply are the major source of discharge, resulting in substantial vertical components of groundwater flow. The decrease in concentrations of many constituents with depth reflects in part that groundwater gets older with depth. Tritium, helium-isotopes, and carbon-14 data were used to classify the predominant age of groundwater samples into three categories: modern (water that has entered the aquifer in the last 50 years), pre-modern (water that entered the aquifer more than 50 years, up to tens of thousands of years, ago), and mixed (mixtures of waters with modern and pre-modern ages). Uranium, nitrate, and herbicide concentrations were significantly higher in groundwater having modern- and mixed-ages than pre-modern ages, indicating that these constituents may be affected by anthropogenic activities in the last 50 years. Other patterns in the distribution of nitrate, uranium, and TDS are evident. Isotopic and geochemical data are consistent with partial denitrification of nitrate in some reducing groundwaters in the western and deeper parts of the flow system. Uranium and TDS concentrations increase from east to west across the valley, along the direction of regional lateral groundwater flow. High and moderate relative-concentrations of arsenic can be attributed to reductive dissolution of manganese or iron oxides, or to desorption by high pH waters. Arsenic concentrations also increased with increasing depth and groundwater age. High to moderate relative-concentrations of vanadium primarily are related to high pH under oxic conditions. The frequency of detections of DBCP was greater in areas with orchard-vineyard land use >40 percent and at depths <200 feet. THMs and solvents were correlated positively with percent urban land use. Herbicide concentrations were correlated negatively with percent natural land use. Perchlorate concentrations were significantly greater in waters having modern and mixed ages than waters having pre-modern ages and were significantly and positively correlated with two land uses—percent orchard/vineyard land use and percent urban land use.

California↗
USGS2013

Pilot study of natural attenuation of arsenic in well water discharged to the Little River above Lake Thunderbird, Norman, Oklahoma, 2012

The City of Norman, Oklahoma, wanted to augment its water supplies to meet the needs of an increasing population. Among the city’s potential water sources are city wells that produce water that exceeds the 10 micrograms per liter primary drinking-water standard for arsenic. The City of Norman was interested in investigating low-cost means of using natural attenuation to remove arsenic from well water and augment the water supply of Lake Thunderbird, the primary water source for the city. The U.S. Geological Survey, in cooperation with the City of Norman, conducted a preliminary investigation (pilot study) to determine if discharge of water from those wells into the Little River over a 12-day period would reduce arsenic concentrations through natural-attenuation processes. Water in the Little River flows into Lake Thunderbird, the principal water source for the city, so the discharged well water would improve the water balance of that reservoir. During this pilot study, 150–250 gallons per minute from each of six city wells were discharged to the Little River over a 12-day period. Water-quality samples were collected from the wells during discharge and from the river before, during, and after well discharges. Streambed-sediment samples were collected at nine sites in the river before and after the well-discharge period. Water discharge from the six wells added 0.3 kilogram per day of arsenic to the river at the nearest downstream streamflow-gaging station. Dissolved arsenic concentration in the Little River at the closest downstream sampling site from the wells increased from about 4 micrograms per liter to as much as 24 micrograms per liter. Base flow in the river increased by about 1.7 cubic feet per second at the nearest downstream streamflow-gaging station. Streamflow in the river was two-thirds of that expected from the amount of water discharged from the wells because of seepage to soils and evapotranspiration of well water along drainage ways to the river. Arsenic concentrations at the nearest downstream streamflow-gaging station were less than arsenic concentrations measured in many of the well-water samples during the well-pumping period. Arsenic concentrations, loads, and yields in the Little River generally decreased downstream from the closest streamflow-gaging station to the wells by 50 percent or more, indicating removal of about 0.25 kilogram or 0.53 pound per day of arsenic during base-flow conditions. Measured river-water arsenic concentrations near the confluence of the Little River with Lake Thunderbird were in compliance with the primary drinking-water standard. Arsenic concentrations measured at four downstream stations in the Little River also were less than established criteria set for protection of aquatic biota. After well discharges to the Little River were stopped, arsenic concentrations, loads, and yields in the river gradually decreased over 14 days to concentrations measured prior to the well-water discharges. Cumulative loads of arsenic discharged at the wells and the closest and farthest downstream streamflow-gaging stations indicated removal of about 2.5 kilograms of arsenic as well-water flowed to and down the river. Arsenic concentrations in streambed-sediment samples collected before and after the well-water discharges were not significantly different. Results of this pilot study indicate that using natural-attenuation processes to remove arsenic from water and supplement city water supplies may be a viable, relatively low-cost method for attenuating arsenic in well water and for augmenting the water supply of Lake Thunderbird.

Oklahoma↗
USGS2001

U.S. Geological Survey Information Sources

As the Nation's largest water, earth, and biological science and civilian mapping agency, the U.S. Geological Survey (USGS) works in cooperation with more than 2,000 organizations across the country to provide reliable, impartial scientific information to resource managers, planners, and other customers. This information is gathered in every State by USGS scientists to minimize the loss of life and property from natural disasters, to contribute to the conservation and the sound economic and physical development of the Nation's natural resources, and to enhance the quality of life by monitoring water, biological, energy, and mineral resources

Fact Sheet↗
USGS2000

U.S. Geological Survey Information Sources

As the nation's largest water, earth and biological science and civilian mapping agency, the U.S. Geological Survey (USGS) works in cooperation with more than 2000 organizations across the country to provide reliable, impartial, scientific information to resource managers, planners, and other customers. This information is gathered in every state by USGS scientists to minimize the loss of life and property from natural disasters, to contribute to the conservation and the sound economic and physical development of the nation's natural resources, and to enhance the quality of life by monitoring water, biological, energy and mineral resources.

Fact Sheet↗
USGS2008

Geologic resource evaluation of Pu'ukohola Heiau National Historic Site, Hawai'i; Part I, geology and coastal landforms

Geologic resource inventories of lands managed by the National Park Service (NPS) are important products for the parks and are designed to provide scientific information to better manage park resources. Park-specific geologic reports are used to identify geologic features and processes that are relevant to park ecosystems, evaluate the impact of human activities on geologic features and processes, identify geologic research and monitoring needs, and enhance opportunities for education and interpretation. These geologic reports are planned to provide a brief geologic history of the park and address specific geologic issues forming a link between the park geology and the resource manager. The Kona coast National Parks of the Island of Hawai'i are intended to preserve the natural beauty of the Kona coast and protect significant ancient structures and artifacts of the native Hawaiians. Pu'ukohola Heiau National Historic Site (PUHE), Kaloko-Honokohau National Historical Park (KAHO), and Pu'uhonua O Honaunau National Historical Park (PUHO) are three Kona parks studied by the U.S. Geological Survey (USGS) Coastal and Marine Geology Team in cooperation with the National Park Service. This report is one of six related reports designed to provide geologic and benthic-habitat information for the three Kona parks. Each geology and coastal-landform report describes the regional geologic setting of the Hawaiian Islands, gives a general description of the geology of the Kona coast, and presents the geologic setting and issues for one of the parks. The related benthic-habitat mapping reports discuss the marine data and habitat classification scheme, and present results of the mapping program. Pu'ukohola Heiau National Historic Site (PUHE) is the smallest (~86 acres) of three National Parks located on the leeward Kona coast of the Island of Hawai'i. The main structure at PUHE, Pu'ukohola Heiau, is an important historical temple that was built during 1790-91 by King Kamehameha I (also known as Kamehameha the Great) and is often associated with the founding of the Hawaiian Kingdom (Greene, 1993). The temple was constructed to incur the favor of the king's personal war god Kuka'ilimoku during the time that Kamehameha I waged several battles in an attempt to extend his control over all the Hawaiian Islands. The park is also the site of the older Mailekini Heiau, which was used by the ancestors of Kamehameha I, and an offshore, submerged temple, Hale O Kapuni Heiau, that was dedicated to the shark god. The park occupies the scenic Hill of the Whale overlooking Kawaihae Bay and Pelekane Beach. The seaward-sloping lands of PUHE lie at the convergence of lava flows formed by both Mauna Kea and Kohala Volcanoes. The park coastline is mostly rocky, with the exception of a small beach developed at the north boundary where an intermittent stream enters the sea. The park is bounded to the north by Kawaihae Harbor, to the south by Samuel M. Spencer Beach Park, and to the west by a broad submerged reef. The adjacent reef area is discussed in detail in the accompanying report by Cochran and others (2006). They mapped from the shoreline to depths of approximately 40 m, where the shelf drops off to a sand-covered bottom. PUHE park boundaries extend only to the mean high-tide line, however, landscape impacts created by development around the park are of concern to Park management.

Hawaii↗
USGS2008

Geologic resource evaluation of Pu'uhonua O Honaunau National Historical Park, Hawai'i; Part I, geology and coastal landforms

Geologic resource inventories of lands managed by the National Park Service (NPS) are important products for the parks and are designed to provide scientific information to better manage park resources. Park-specific geologic reports are used to identify geologic features and processes that are relevant to park ecosystems, evaluate the impact of human activities on geologic features and processes, identify geologic research and monitoring needs, and enhance opportunities for education and interpretation. These geologic reports are planned to provide a brief geologic history of the park and address specific geologic issues forming a link between the park geology and the resource manager. The Kona coast National Parks of the Island of Hawai'i are intended to preserve the natural beauty of the Kona coast and protect significant ancient structures and artifacts of the native Hawaiians. Pu'ukohola Heiau National Historic Site (PUHE), Kaloko-Honokohau National Historical Park (KAHO), and Pu'uhonua O Honaunau National Historical Park (PUHO) are three Kona parks studied by the U.S. Geological Survey (USGS) Coastal and Marine Geology Team in cooperation with the National Park Service. This report is one of six related reports designed to provide geologic and benthic-habitat information for the three Kona parks. Each geology and coastal-landform report describes the regional geologic setting of the Hawaiian Islands, gives a general description of the geology of the Kona coast, and presents the geologic setting and issues for one of the parks. The related benthic-habitat mapping reports discuss the marine data and habitat classification scheme, and present results of the mapping program. Pu'uhonua O Honaunau National Historical Park ('Place of Refuge of Honaunau') is the southernmost of the three National Parks located on the leeward Kona coast of the Island of Hawai'i. It is a relatively small park originally 73 ha (182 acres), and was expanded in 2006 with the acquisition of an additional 96 ha (238 acres). The park is probably best known for the pu'uhonua (place of refuge) native Hawaiian cultural site. In addition to the pu'uhonua, the park contains palace grounds, royal fishponds, burial sites, prehistoric trails, a royal canoe landing area, stone house platforms and associated temple structures. A massive basalt rock wall (300 m long, 3 m high, and 5 m wide) separates the pu'uhonua from the areas used by Hawaiian royalty and other grounds. Honaunau Bay is a popular marine resource area adjacent to the park. The seaward-sloping lands of PUHO lie at the base of Mauna Loa volcano, which forms a bench of low-lying pahoehoe lava flows at Pu'uhonua Point. The park coastline is approximately 1.6 km long and is mostly rocky with the exception of a small artificially nourished beach at Keone'ele Cove at the northern boundary next to Honaunau Bay. The park is bounded to the south by Ki'ilae Bay and includes the coastal portions of three Hawaiian land divisions (ahupua'a): Honaunau, Keokea, and Ki'ilae. The western boundary is the high tide mark. The waters of Keone'ele Cove, the ancient royal canoe landing at PUHO, while not formally under NPS jurisdiction, are managed by the park under an agreement with the State of Hawai'i. This small embayment is a known haven for sea turtles, which are often found sunning themselves on the nearshore volcanic platform. Impacts to this area include frequent visits by scuba divers and snorkelers to Honaunau Bay and a small boat ramp located just to the north of Keone'ele Cove. There is an accompanying report that presents the results of benthic habitat mapping of the offshore waters for PUHO (Cochran and others, 2006b; linked below). They mapped from the shoreline to depths of approximately 40 m, where the shelf drops off to a sand-covered bottom. PUHO park boundaries extend only to the mean high-tide level; however, landscape impacts created by development around the park are of concern to

Hawaii↗
USGS2010

Groundwater-quality monitoring program in Chester County, Pennsylvania, 1980-2008

The U.S. Geological Survey in cooperation with the Chester County Water Resources Authority and the Chester County Health Department began a groundwater-quality monitoring program in 1980 in Chester County, Pa., where a large percentage of the population relies on wells for drinking-water supply. This report documents the program and serves as a reference for data collected through the program from 1980 through 2008. The initial focus of the program was to collect data on groundwater quality near suspected localized sources of contamination, such as uncontrolled landfills and suspected industrial wastes, to determine if contaminants were present that might pose a health risk to those using the groundwater. Subsequently, the program was expanded to address the effects of widely distributed contaminant sources associated with agricultural and residential land uses on groundwater quality and to document naturally occurring constituents, such as radium, radon, and arsenic, that are potential hazards in drinking water. Since 2000, base-flow stream samples have been collected in addition to well-water and spring samples in a few small drainage areas to investigate the relation between groundwater quality measured in well samples and streams. The program has primarily consisted of spatial assessment with limited temporal data collected on groundwater quality. Most data were collected through the monitoring program for reconnaissance purposes to identify and locate groundwater-quality problems and generally were not intended for rigorous statistical analyses that might determine land-use or geochemical factors affecting groundwater quality in space or through time. Results of the program found several contaminants associated with various land uses and human activities in groundwater in Chester County. Volatile organic compounds (such as trichloroethylene) were measured in groundwater near suspected localized contaminant sources in concentrations that exceeded drinking-water standards. Groundwater in some agricultural areas had concentrations of nitrate and some pesticides that exceeded drinking-water standards. Elevated concentrations of chloride were measured near salt storage areas and highways. Formaldehyde was detected in groundwater near cemeteries. In residential areas with on-site wastewater disposal, effects on groundwater quality included elevated nitrate concentrations and low concentrations of volatile organic compounds and wastewater compounds, such as antibiotics and detergents. Base-flow samples indicated that groundwater discharge to streams carried contaminants such as nitrate, pesticides, wastewater compounds, and other contaminants. Radionuclides, including radium-226, radium-228, radium-224, and radon-222, and gross alpha-particle activity were measured in groundwater at levels above established and proposed drinking-water standards in some geologic units, particularly in quartzite and quartzite schists. Arsenic concentrations above drinking-water standards were measured in a few samples and were most likely to occur in groundwater in the shales and sandstones in the northern part of the county. Other potential natural hazards, such as lead from aquifer materials or leached from plumbing because of pH, were present in concentrations above drinking-water standards infrequently (less than 10 percent of samples). Limited temporal sampling suggested that chloride concentrations in groundwater increased in the county since the program began in 1980 through 2008, reflecting increasing population and urbanization in that period.

Scientific Investigations Report↗
USGS2024

Hydrology and water quality of a dune-and-swale wetland adjacent to the Grand Calumet River, Indiana, 2019–22

Adverse ecological and water-quality effects associated with industrial land-use changes are common for littoral wetlands connected to river mouth ecosystems in the Grand Calumet River-Indiana Harbor Canal Area of Concern. These effects can be exacerbated by recent high Lake Michigan water levels that are problematic for wetland restoration. Wetlands in the adjacent Clark and Pine Nature Preserve and Pine Station Nature Preserve are intended to mitigate wetland destruction in the area of concern by restoring residual dune-and-swale wetlands and preserving habitat for endangered and threatened plant species. Physical hydrology and water-quality monitoring of restored wetland cells at the preserves were initiated during 2019 to evaluate changes after wetland restoration efforts in 2015 and near record-low water levels in early 2013. Lake Michigan water levels rose steadily between late 2013 and 2018 to record-high water levels in 2019 and 2020. In this report, precipitation, evapotranspiration, and groundwater and surface-water levels are analyzed to better understand wetland inundation controls and flow directions in restored northern dune-and-swale wetland settings relative to the Grand Calumet River. Continuous specific conductance data and discrete water-quality samples were collected and analyzed to provide a synoptic view of water quality for the restored wetlands. High Lake Michigan water levels affected Grand Calumet River stage and shallow groundwater elevations in the study area after the onset of peak lake levels in June 2019, that persisted through summer 2020, before finally receding in September 2020. Grand Calumet River stage peaked soon after lake levels in July 2019, whereas groundwater elevations in the study area peaked in October 2019. Specific conductance values in closed-basin wetland cells in the western and central parts of the nature preserves indicated a dilution trend and contrasted those of interconnected wetland cells along an eastern corridor, where alterations to wetland cells were more pronounced. Monitoring results indicate that varying seasonal wetland inundation trends with low stands in autumn have returned after high water table conditions owing to high water levels on Lake Michigan. Wetland water balance results during the study period indicated that the wetland ecosystem partially moderated flooding during high lake levels through summer evapotranspiration.

Indiana↗
USGS2022

Vegetation map for the Seboeis Unit of Katahdin Woods and Waters National Monument

The Katahdin Woods and Waters National Monument, located in the forests of central Maine, is a newly (2016) established unit for the National Park Service. To better understand the condition of lands within the monument and inform management planning, Katahdin Woods and Waters National Monument resource managers wanted better information of the vegetation present within the monument. To meet this need, scientists at the U.S. Geological Survey Upper Midwest Environmental Sciences Center worked with ecologists at the Maine Natural Areas Program to catalog and map the vegetation of the Seboeis Unit of the monument. This report details this process, provides results of the survey and mapping efforts, presents results in the form of a vegetation map for the Seboeis Unit, and provides vegetation descriptions and a dichotomous key for the entire Katahdin Woods and Waters National Monument.

Maine↗