SEARCH · USGS Science

Results for “Water Surface Techniques”

Search indexed USGS publications on groundwater, aquifers, geologic maps, mineral resources and earthquakes. Explore source records by subject and place.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 667 records · Page 37Linked to original sources

USGS2012

Approaches in highly parameterized inversion: TSPROC, a general time-series processor to assist in model calibration and result summarization

The TSPROC ( T ime S eries PROC essor) computer software uses a simple scripting language to process and analyze time series. It was developed primarily to assist in the calibration of environmental models. The software is designed to perform calculations on time-series data commonly associated with surface-water models, including calculation of flow volumes, transformation by means of basic arithmetic operations, and generation of seasonal and annual statistics and hydrologic indices. TSPROC can also be used to generate some of the key input files required to perform parameter optimization by means of the PEST ( P arameter EST imation) computer software. Through the use of TSPROC, the objective function for use in the model-calibration process can be focused on specific components of a hydrograph.

Techniques and Methods↗

USGS2008

Chapter A7 Biological Indicators

The National Field Manual for the Collection of Water-Quality Data (National Field Manual) provides guidelines and standard procedures for U.S. Geological Survey (USGS) personnel who collect data used to assess the quality of the Nation's surface-water and ground-water resources. This chapter of the manual includes procedures for the (1) determination of biochemical oxygen demand using a 5-day bioassay test; (2) collection, identification, and enumeration of fecal indicator bacteria; (3) collection of samples and information on two laboratory methods for fecal indicator viruses (coliphages); and (4) collection of samples for protozoan pathogens. Each chapter of the National Field Manual is published separately and revised periodically. Newly published and revised chapters will be announced on the USGS Home Page on the World Wide Web under 'New Publications of the U.S. Geological Survey.'

Techniques of Water-Resources Investigations↗

USGS2008

Mid-Pliocene Planktic Foraminifer Census Data and Alkenone Unsaturation Indices from Ocean Drilling Program Hole 677A

The U.S. Geological Survey is conducting a long-term study of mid-Pliocene climatic and oceanographic conditions. One of the key elements of the study involves the use of quantitative composition of planktic foraminifer assemblages in conjunction with other proxies to constrain estimates of sea-surface temperature (SST) and to identify major oceanographic boundaries and water masses. Raw census data are made available as soon as possible after analysis through a series of reports that provide the basic data for future work. In this report we present raw census data (table 1) for planktic foraminifer assemblages in 14 samples from Ocean Drilling Program (ODP) Hole 677A. We also present alkenone unsaturation index (UK'37) analyses for 89 samples from ODP Hole 677A (table 2). ODP Hole 677A is located in the Panama basin, due west of Ecuador at 1?12.138'N., 83?44.220'W., in 3461.2 meters of water (fig. 1). A variety of statistical methods have been developed to transform foraminiferal census data in Pliocene sequences into quantitative estimates of Pliocene SST. Details of statistical techniques, taxonomic groupings, and oceanographic interpretations are presented in more formal publications (Dowsett and Poore, 1990, 1991; Dowsett, 1991, 2007a,b; Dowsett and Robinson, 1998, 2007; Dowsett and others, 1996, 1999).

Data Series↗

USGS2015

Groundwater – The disregarded component in lake water and nutrient budgets. Part 2: effects of groundwater on nutrients

Lacustrine groundwater discharge (LGD) transports nutrients from a catchment to a lake, which may fuel eutrophication, one of the major threats to our fresh waters. Unfortunately, LGD has often been disregarded in lake nutrient studies. Most measurement techniques are based on separate determinations of volume and nutrient concentration of LGD: Loads are calculated by multiplying seepage volumes by concentrations of exfiltrating water. Typically low phosphorus (P) concentrations of pristine groundwater often are increased due to anthropogenic sources such as fertilizer, manure or sewage. Mineralization of naturally present organic matter might also increase groundwater P. Reducing redox conditions favour P transport through the aquifer to the reactive aquifer-lake interface. In some cases, large decreases of P concentrations may occur at the interface, for example, due to increased oxygen availability, while in other cases, there is nearly no decrease in P. The high reactivity of the interface complicates quantification of groundwater-borne P loads to the lake, making difficult clear differentiation of internal and external P loads to surface water. Anthropogenic sources of nitrogen (N) in groundwater are similar to those of phosphate. However, the environmental fate of N differs fundamentally from P because N occurs in several different redox states, each with different mobility. While nitrate behaves essentially conservatively in most oxic aquifers, ammonium's mobility is similar to that of phosphate. Nitrate may be transformed to gaseous N 2 in reducing conditions and permanently removed from the system. Biogeochemical turnover of N is common at the reactive aquifer-lake interface. Nutrient loads from LGD were compiled from the literature. Groundwater-borne P loads vary from 0.74 to 2900 mg PO 4 -P m −2 year −1 ; for N, these loads vary from 0.001 to 640 g m −2 year −1 . Even small amounts of seepage can carry large nutrient loads due to often high nutrient concentrations in groundwater. Large spatial heterogeneity, uncertain areal extent of the interface and difficult accessibility make every determination of LGD a challenge. However, determinations of LGD are essential to effective lake management.

Hydrological Processes↗

USGS2005

Borehole-geophysical and hydraulic investigation of the fractured-rock aquifer near the University of Connecticut Landfill, Storrs, Connecticut, 2000 to 2001

An integrated borehole-geophysical and hydraulic investigation was conducted at the former landfill area near the University of Connecticut in Storrs, Connecticut, where solvents and landfill leachate have contaminated a fractured-bedrock aquifer. Borehole-geophysical techniques and hydraulic methods were used to characterize the site bedrock lithology and structure, fractures, and hydraulic properties. The geophysical and hydraulic methods included conventional logs, borehole imaging, borehole radar, flowmeter under ambient- and stressed hydraulic conditions, and discrete-zone hydraulic testing, sampling, and monitoring. The conventional geophysical-logging methods included caliper, deviation, electromagnetic induction, gamma, specific conductance, and fluid temperature. The advanced methods included optical and acoustic imaging of the borehole wall, heat-pulse flowmeter, and directional radar reflection. Borehole-geophysical methods were used to further define conductive features identified with surface-geophysical methods in the first phase of the investigation. The results of the surface- and borehole-geophysical logging were evaluated in an iterative and integrated manner to develop a conceptual model of ground-water flow at the site. The rock type, foliation, and fractures at the site were characterized from high-resolution optical televiewer (OTV) images of rocks penetrated by the boreholes and were compared to drilling logs and conventional geophysical logs. The rocks are interpreted as fine- to mediumgrained quartz-feldspar-biotite-garnet gneiss and schist with local intrusions of quartz diorite and pegmatite and minor concentrations of sulfide mineralization similar to rocks described as the Bigelow Brook Formation on regional geologic maps. Layers containing high concentrations of sulfide minerals appear as high electrical conductivity zones on electromagnetic-induction and borehole-radar logs. Foliation in the rocks generally strikes to the southwest and northeast, and dips to the northwest and southeast consistent with previous investigations in this area. The orientation of foliation, however, varies locally and with depth in some of the boreholes. These results are consistent with geologic mapping that has identified small-scale folding. The orientations of the transmissive fractures identified in the six boreholes logged for this investigation are similar to the fracture orientations mapped in a previous investigation. Many of these fractures are oriented with a north-northwest strike and have a shallow dip to the west. Other transmissive fractures have a southwest strike and dip at shallow angles to the northwest, and some strike roughly east-west and dip to the north and south. Flowmeter logging was used to identify transmissive fractures and to estimate the hydraulic properties in the boreholes. Ambient down flow was measured in one borehole, and ambient up flow and down flow were measured in another borehole. The other four bedrock boreholes did not have measurable vertical flow. Under low-rate pumping conditions (0.25 to 0.5 gallons per minute), one to three inflow zones were identified in each well. Commonly, fractures that are active under ambient conditions contribute to the well under pumping conditions. The ambient conditions were incorporated into the determination of the relative proportions of transmissivity. Specific capacity and transmissivity were determined for these open-hole low-rate pumping tests. Quasi-steady-state water levels were reached in four of the boreholes, including MW201R, MW204R, MW302R, and W202-NE. When pumped at low-rate conditions for 0.5 to 4 hours, the specific capacity ranged from 0.03 to 0.18 gallons per minute per foot. The open-hole transmissivity estimates ranged from 4.9 to 30 feet squared per day (ft2/d). Open-hole transmissivity was determined for boreholes that did not reach quasi-steady-state conditions under low-rate pumping conditions. Transmissivity was estimated for MW201R, MW202R, and MW203R using non-equilibrium methods, pumping rate, and the transient drawdown data to estimate the open-hole transmissivity. Transmissivity in these boreholes ranged from 0.98 to 3.2 ft 2 /d. The transmissivity and head of individual fractures or zones of fractures were estimated from heat-pulse flowmeter data acquired under ambient and stressed conditions. In the absence of ambient flow, data from two profiles of heat-pulse flowmeter data under two different stressed conditions were used to estimate the transmissivity and head of individual fracture zones. Only two boreholes, MW302R and W202-NE, had sufficient data for these analyses. The estimated transmissivity of individual transmissive zones ranged from 1.2 to 9.2 ft 2 /d. The transmissivity values determined by this numerical simulation method were less than the open-hole estimations, which were 15 and 30 ft 2 /d. Transmissivity also was measured directly over discrete intervals of the borehole using a straddle-packer apparatus and constant-rate pumping tests. Pumping rates were less than or equal to 0.25 gallons per minute. These discretezone single-hole pumping tests were conducted over a short period of time, usually about 30 minutes to 1 hour in duration. Pumping continued until the test zone reached a steady-state water level or until it was determined that the zone could not yield water at the pumped rate. The estimated transmissivity of individual transmissive zones ranged from about 0.21 to 11 ft 2 /d. The zone at a depth of 197 feet in W202-NE was the only zone that had discrete-interval testing with a straddle packer and sufficient heat-pulse flowmeter data for modeling the flow and estimating transmissivity and head. The two methods produced similar results. The straddle-packer method estimated a transmissivity of 4.7 ft 2 /d, and the heat-pulse flowmeter modeling results estimated a transmissivity of 6.9 ft 2 /d. A comparison of the transmissivity estimates indicate estimates typically are within an order of magnitude. The heat-pulse flowmeter methods used in this investigation to determine transmissivity of the boreholes and the individual fractures measure only the upper two or three orders of magnitude of transmissivity. Hence, other fractures in these boreholes permit the movement of water; their transmissivities, however, are lower than the detection limits of the methods that were used for this investigation and very small compared to the transmissive fractures that were studied. The data collected in this investigation were used to design discrete-zone monitoring systems for four of the boreholes used for monitoring. The results of the investigation are useful for refining the conceptual site model of ground-water flow, and for providing critical information for interpreting the results of water-quality sampling.

Connecticut↗

USGS2017

Water, Energy, and Biogeochemical Model (WEBMOD), user’s manual, version 1

The Water, Energy, and Biogeochemical Model (WEBMOD) uses the framework of the U.S. Geological Survey (USGS) Modular Modeling System to simulate fluxes of water and solutes through watersheds. WEBMOD divides watersheds into model response units (MRU) where fluxes and reactions are simulated for the following eight hillslope reservoir types: canopy; snowpack; ponding on impervious surfaces; O-horizon; two reservoirs in the unsaturated zone, which represent preferential flow and matrix flow; and two reservoirs in the saturated zone, which also represent preferential flow and matrix flow. The reservoir representing ponding on impervious surfaces, currently not functional (2016), will be implemented once the model is applied to urban areas. MRUs discharge to one or more stream reservoirs that flow to the outlet of the watershed. Hydrologic fluxes in the watershed are simulated by modules derived from the USGS Precipitation Runoff Modeling System; the National Weather Service Hydro-17 snow model; and a topography-driven hydrologic model (TOPMODEL). Modifications to the standard TOPMODEL include the addition of heterogeneous vertical infiltration rates; irrigation; lateral and vertical preferential flows through the unsaturated zone; pipe flow draining the saturated zone; gains and losses to regional aquifer systems; and the option to simulate baseflow discharge by using an exponential, parabolic, or linear decrease in transmissivity. PHREEQC, an aqueous geochemical model, is incorporated to simulate chemical reactions as waters evaporate, mix, and react within the various reservoirs of the model. The reactions that can be specified for a reservoir include equilibrium reactions among water; minerals; surfaces; exchangers; and kinetic reactions such as kinetic mineral dissolution or precipitation, biologically mediated reactions, and radioactive decay. WEBMOD also simulates variations in the concentrations of the stable isotopes deuterium and oxygen-18 as a result of varying inputs, mixing, and evaporation. This manual describes the WEBMOD input and output files, along with the algorithms and procedures used to simulate the hydrology and water quality in a watershed. Examples are presented that demonstrate hydrologic processes, weathering reactions, and isotopic evolution in an alpine watershed and the effect of irrigation on water flows and salinity in an intensively farmed agricultural area.

Techniques and Methods↗

USGS2017

Groundwater flow model for the Little Plover River basin in Wisconsin’s Central Sands

The Little Plover River is a groundwater-fed stream in the sand plains region of central Wisconsin. In this region, sandy sediment deposited during or soon after the last glaciation forms an important unconfined sand and gravel aquifer. This aquifer supplies water for numerous high-capacity irrigation, municipal, and industrial wells that support a thriving agricultural industry. In recent years the addition of many new wells, combined with observed diminished flows in the Little Plover and other nearby rivers, has raised concerns about the impacts of the wells on groundwater levels and on water levels and flows in nearby lakes, streams, and wetlands. Diverse stakeholder groups, including well operators, Growers, environmentalists, local land owners, and regulatory and government officials have sought a better understanding of the local groundwater-surface water system and have a shared desire to balance the water needs of the he liagricultural, industrial, and urban users with the maintenance and protection of groundwater-dependent natural resources. To help address these issues, the Wisconsin Department of Natural Resources requested that the Wisconsin Geological and Natural History Survey and U.S. Geological Survey cooperatively develop a groundwater flow model that could be used to demonstrate the relationships among groundwater, surface water, and well withdrawals and also be a tool for testing and evaluating alternative water management strategies for the central sands region. Because of an abundance of previous studies, data availability, local interest, and existing regulatory constraints the model focuses on the Little Plover River watershed, but the modeling methodology developed during this study can apply to much of the larger central sands of Wisconsin. The Little Plover River groundwater flow model simulates three-dimensional groundwater movement in and around the Little Plover River basin under steady-state and transient conditions. This model explicitly includes all high-capacity wells in the model domain and simulates seasonal variations in recharge and well pumping. The model represents the Little Plover River, and other significant streams and drainage ditches in the model domain, as fully connected to the groundwater system, computes stream base flow resulting from groundwater discharge, and routes the flow along the stream channel. A separate soil-water-balance (SWB) model was used to develop groundwater recharge arrays as input for the groundwater flow model. The SWB model uses topography, soils, land use, and climatic data to estimate recharge as deep drainage from the soil zone. The SWB model explicitly includes recharge originating as irrigation water, and computes irrigation using techniques similar to those used by local irrigation operators. The groundwater flow model uses the U.S. Geological Survey’s MODFLOW modeling code which is freely available, widely accepted, and commonly used by the groundwater community. The groundwater flow model and the SWB model use identical high-resolution numerical grids having model cells 100 feet on a side, with physical properties assigned to each grid cell. This grid allows accurate geographic placement of wells, streams, and other model features. The 3-dimensional grid has three layers; layers 1 and 2 represent the sand and gravel aquifer and layer 3 represents the underlying sandstone. The distribution of material properties in the model (hydraulic conductivity, aquifer thickness, etc.) comes from previous published geologic studies of the region, updated by calibration to recent streamflow and groundwater level data. The SWB model operates on a daily time step. The groundwater flow model was calibrated to monthly stress periods with time steps ranging from 1 to 16 days. More detailed time discretization is possible. The groundwater model was calibrated to water-level and streamflow data collected during 2013 and 2014 by adjusting model parameters (primarily hydraulic conductivity, storage, and recharge) until the model produced a conditionally optimal fit between field observations and model output, subject to consistency with previously published geologic studies. Calibration was performed under both steady and transient conditions, and used a sophisticated parameter-estimation procedure (PEST) for the calibration process and to identify important model parameters. For the Little Plover River, the two most important parameters are the global recharge multiplier and the hydraulic conductivity of the stream bed. The calibrated model produces water-level and mass-balance results that are consistent with field observations and previous studies of the area. The completed model is a powerful tool for testing and demonstrating alternative water-management scenarios. Example model applications described in this report include simulating how the cumulative impacts of pumping and land-use change have affected average baseflow in the Little Plover River. Depletion-potential mapping represents a method for predicting which wells and well locations have the greatest impact on nearby surface-water resources. The completed model is publicly available, along with a companion user’s guide to assist with its operation, at http://wgnhs.org/littleplover- river-groundwater-model.

Wisconsin↗

USGS2012

Potential pollutant sources in a Choptank River (USA) subwatershed and the influence of land use and watershed characteristics

Row-crop and poultry production have been implicated as sources of water pollution along the Choptank River, an estuary and tributary of the Chesapeake Bay. This study examined the effects of land use, subwatershed characteristics, and climatic conditions on the water quality parameters of a subwatershed in the Choptank River watershed. The catchments within the subwatershed were defined using advanced remotely-sensed data and current geographic information system processing techniques. Water and sediment samples were collected in May–October 2009 and April–June 2010 under mostly baseflow conditions and analyzed for select bacteria, nitrate-N, ammonium-N, total arsenic, total phosphorus (TP), orthophosphate (ortho-P), and particle-phase phosphorus (PP); n = 96 for all analytes except for arsenic, n = 136, and for bacteria, n = 89 (aqueous) and 62 (sediment). Detections of Enterococci and Escherichia coli concentrations were ubiquitous in this subwatershed and showed no correlation to location or land use, however larger bacterial counts were observed shortly after precipitation. Nitrate-N concentrations were not correlated with agricultural lands, which may reflect the small change in percent agriculture and/or the similarity of agronomic practices and crops produced between catchments. Concentration data suggested that ammonia emission and possible deposition to surface waters occurred and that these processes may be influenced by local agronomic practices and climatic conditions. The negative correlation of PP and arsenic concentrations with percent forest was explained by the stronger signal of the head waters and overland flow of particulate phase analytes versus dissolved phase inputs from groundwater. Service roadways at some poultry production facilities were found to redirect runoff from the facilities to neighboring catchment areas, which affected water quality parameters. Results suggest that in this subwatershed, catchments with poultry production facilities are possible sources for arsenic and PP as compared to catchment areas where these facilities were not present.

Choptank River↗

USGS2025

Determination of per- and polyfluoroalkyl substances in water by direct injection of matrix-modified centrifuge supernatant and liquid chromatography/tandem mass spectrometry with isotope dilution

A direct-injection liquid chromatography/tandem mass spectrometry method was developed to determine 34 per- and polyfluoroalkyl substances (PFAS), including selected branched isomers, in centrifuge supernatant of matrix-modified (amended with approximately 50 percent methanol) water samples. The method has been validated in reagent water, surface water, groundwater, and wastewater effluent. Other water types (for example, drinking water, untreated wastewater, and landfill leachate) have been analyzed by the method but not systematically validated. Recovery of isotope-dilution standards, added to each sample, may be used to assess method performance in nonvalidated matrices on a sample-by-sample basis. Using this method, PFAS concentrations were determined in the range of 2–2,000 nanograms per liter in water samples. This range can be extended by diluting concentrated samples. At circumneutral pH, most compounds are present in the environment in their ionized form, and data are reported as such (for example, perfluorooctanoic acid is referred to as “perfluorooctanoate” [PFOA], perfluorooctane sulfonic acid is referred to as “perfluorooctane sulfonate” [PFOS]). Sample preparation procedures were designed without the use of filtration and with minimum sample handling steps to mitigate procedural losses of target compounds due to sorption to surfaces. Further, isotope-dilution quantification allowed for the correction of bias that may result from procedural losses, matrix-induced signal suppression or enhancement, and other factors. Validation experiments to characterize bias and variability, method detection level, and holding time were done in four distinct water matrices—reagent water, surface water, treated wastewater effluent, and groundwater—at multiple concentration levels. Mean PFAS recoveries met data quality objectives of bias and variability studies in all four validation matrices except for two compounds with low and variable recovery in the reagent water matrix only. Isotope-dilution standards, treated as surrogate compounds, were analyzed in more than 1,500 customer-submitted environmental samples with aggregate recovery of 102.5±6.5 percent (mean±standard deviation). Maximum holding times for all target compounds in the four validation matrices were 28 days for refrigerated samples and 90 days for frozen samples.

Techniques and Methods↗

USGS2002

Recharge and groundwater models: An overview

Recharge is a fundamental component of groundwater systems, and in groundwater-modeling exercises recharge is either measured and specified or estimated during model calibration. The most appropriate way to represent recharge in a groundwater model depends upon both physical factors and study objectives. Where the water table is close to the land surface, as in humid climates or regions with low topographic relief, a constant-head boundary condition is used. Conversely, where the water table is relatively deep, as in drier climates or regions with high relief, a specified-flux boundary condition is used. In most modeling applications, mixed-type conditions are more effective, or a combination of the different types can be used. The relative distribution of recharge can be estimated from water-level data only, but flux observations must be incorporated in order to estimate rates of recharge. Flux measurements are based on either Darcian velocities (e.g., stream base-flow) or seepage velocities (e.g., groundwater age). In order to estimate the effective porosity independently, both types of flux measurements must be available. Recharge is often estimated more efficiently when automated inverse techniques are used. Other important applications are the delineation of areas contributing recharge to wells and the estimation of paleorecharge rates using carbon-14.

Hydrogeology Journal↗

USGS2010

Avoidance of strobe lights by zooplankton

Underwater strobe lights can influence the behavior and distribution of fishes and are increasingly used as a technique to divert fish away from water intake structures on dams. However, few studies examine how strobe lights may affect organisms other than targeted species. To gain insight on strobe lighting effects on nontarget invertebrates, we investigated whether underwater strobe lights influence zooplankton distributions and abundance in Lake Oahe, South Dakota. Zooplankton were collected using vertical tows at 3 discrete distances from an underwater strobe light to quantify the influence of light intensity on zooplankton density. Samples were collected from 3 different depth ranges (0–10 m, 10–20 m and 20–30 m) at <1 m, 15 m and ⩾100 m distance intervals away from the strobe light. Copepods represented 67.2% and Daphnia spp. represented 23.3% of all zooplankton sampled from 17 August to 15 September 2004. Night time zooplankton densities significantly decreased in surface waters when strobe lights were activated. Copepods exhibited the greatest avoidance patterns, while Daphnia avoidance varied throughout sampling depths. These results indicate that zooplankton display negative phototaxic behavior to strobe lights and that researchers must be cognizant of potential effects to the ecosystem such as altering predator–prey interactions or affecting zooplankton distribution and growth.

Lake and Reservoir Management↗

USGS2019

Capacity and area of Grand Lake O’ the Cherokees, northeastern Oklahoma, 2009

In February 2017, the Grand River Dam Authority filed to relicense the Pensacola Hydroelectric Project with the Federal Energy Regulatory Commission. The predominant feature of the Pensacola Hydroelectric Project is Pensacola Dam, which impounds Grand Lake O’ the Cherokees (locally called Grand Lake) in northeastern Oklahoma. Identification of information gaps and assessment of project effects on stakeholders are central aspects of the Federal Energy Regulatory Commission relicensing process. Due to the natural changes to the reservoir over time, new capacity and area tables are needed periodically. The most recent complete capacity and area table was produced in 1940. Capacity and area tables identify the relations between the elevation of the water surface and the volume of water that can be impounded at each water surface elevation. This report (1) presents an updated capacity and area table for Grand Lake O’ the Cherokees for 2009, (2) describes the methods used to calculate the updated capacity and area values presented in the table, and (3) compares the updated capacity table to historical capacity tables produced from a survey in 1940 and from a hydrographic survey of the lake by the Oklahoma Water Resources Board in 2009. The new capacity values computed for Grand Lake O’ the Cherokees indicate that capacity at conservation pool elevation has decreased about 157,000 acre-feet or 10 percent since 1940 and capacity at top of dam elevation has decreased about 200,000 acre-feet or 8 percent since 1940. This difference in the capacities could be attributed to the advancements of technologies; the techniques used for surveying lakes have changed from the 1940 survey to the 2009 survey. Another possible reason for loss in capacity could be as time progresses, lakes like Grand Lake O’ the Cherokees slowly impound sediment carried by the rivers that feed into the lakes, thus diminishing the amount of water that the lake holds. The most recent survey used measured water depths and Global Position System collected electronically, but the methods used to collect data in 1940 are unknown. Due to the advancement of technology, the 2009 survey is likely more precise than the 1940 survey.

Oklahoma↗

USGS2015

Lakes and reservoirs—Guidelines for study design and sampling

The “National Field Manual for the Collection of Water-Quality Data” (NFM) is an online report with separately published chapters that provides the protocols and guidelines by which U.S. Geological Survey personnel obtain the data used to assess the quality of the Nation’s surface-water and groundwater resources. Chapter A10 reviews limnological principles, describes the characteristics that distinguish lakes from reservoirs, and provides guidance for developing temporal and spatial sampling strategies and data-collection approaches to be used in lake and reservoir environmental investigations. Within this chapter are references to other chapters of the NFM that provide more detailed guidelines related to specific topics and more detailed protocols for the quality assurance and assessment of the lake and reservoir data. Protocols and procedures to address and document the quality of lake and reservoir investigations are adapted from, or referenced to, the protocols and standard operating procedures contained in related chapters of this NFM. Before 2017, the U.S. Geological Survey (USGS) “National Field Manual for the Collection of Water-Quality Data” (NFM) chapters were released in the USGS Techniques of Water-Resources Investigations series. Effective in 2018, new and revised NFM chapters are being released in the USGS Techniques and Methods series; this series change does not affect the content and format of the NFM. More information is in the general introduction to the NFM (USGS Techniques and Methods, book 9, chapter A0, 2018) at https://doi.org/10.3133/tm9A0 . The authoritative current versions of NFM chapters are available in the USGS Publications Warehouse at https://pubs.er.usgs.gov . Comments, questions, and suggestions related to the NFM can be addressed to nfm-owq@usgs.gov .

Techniques and Methods↗

USGS2024

Guidelines for the use of automatic samplers in collecting surface-water quality and sediment data

The importance of fluvial systems in the transport of sediment, dissolved and suspended contaminants, nutrients, and bacteria through the environment is well established. The U.S. Environmental Protection Agency (EPA) identifies sediment as the single most widespread water contaminant affecting the beneficial uses of the Nation’s rivers and streams. The evaluation of water-quality as it relates to agriculture, urbanization, highway and residential construction, mining, industrial and human wastes, and other activities requires an extensive data and sample-collection effort. This is especially the case when studying urbanized river basins, where during hydrologic events, concentration of suspended sediment and contaminants can vary rapidly and over large ranges. Where synoptic studies of watersheds are called for, sampling may be needed at many sites throughout the basin; a complicated and difficult task in some settings. Automatic pumping samplers (autosamplers) are one method for conducting intensive time-varying sampling throughout watersheds. This report presents guidelines for the use of autosamplers for collecting surface-water samples by the U.S. Geological Survey. An autosampler is an automatic, pump-based sampler that collects a prescribed volume of water from streams, lakes, reservoirs, storm drains, or other bodies of water after receiving a command from an internal or external control unit. It deposits this sample into a specified container for later analysis of physical, chemical, or biological constituents. This report provides a general background on types of autosamplers and how they work; guidance for designing, selecting, installing, servicing, and calibrating autosamplers; guidance on standardized operating procedures, and guidance on quality-assurance and quality-control efforts when using an autosampler.

Techniques and Methods↗

USGS2000

Nutrient pollution of coastal rivers, bays, and seas

Over the past 40 years, antipollution laws have greatly reduced discharges of toxic substances into our coastal waters. This effort, however, has focused largely on point-source pollution of industrial and municipal effluent. No comparable effort has been made to restrict the input of nitrogen (N) from municipal effluent, nor to control the flows of N and phosphorus (P) that enter waterways from dispersed or nonpoint sources such as agricultural and urban runoff or as airborne pollutants. As a result, inputs of nonpoint pollutants, particularly N, have increased dramatically. Nonpoint pollution from N and P now represents the largest pollution problem facing the vital coastal waters of the United States. Nutrient pollution is the common thread that links an array of problems along the nations coastline, including eutrophication, harmful algal blooms, dead zones, fish kills, some shellfish poisonings, loss of seagrass and kelp beds, some coral reef destruction, and even some marine mammal and seabird deaths. More than 60 percent of our coastal rivers and bays in every coastal state of the continental United States are moderately to severely degraded by nutrient pollution. This degradation is particularly severe in the mid Atlantic states, in the southeast, and in the Gulf of Mexico. A recent report from the National Research Council entitled Clean Coastal Waters: Understanding and Reduc- ing the Effects of Nutrient Pollution concludes that: Nutrient over-enrichment of coastal ecosystems generally triggers ecological changes that decrease the biologi- cal diversity of bays and estuaries. While moderate N enrichment of some coastal waters may increase fish production, over-enrichment generally degrades the marine food web that supports commercially valuable fish. The marked increase in nutrient pollution of coastal waters has been accompanied by an increase in harmful algal blooms, and in at least some cases, pollution has triggered these blooms. High nutrient levels and the changes they cause in water quality and the makeup of the algal community are detrimental to the health of coral reefs and the diversity of animal life supported by seagrass and kelp communi- ties. Research during the past decade confirms that N is the chief culprit in eutrophication and other impacts of nutrient over-enrichment in temperate coastal waters, while P is most problematic in eutrophication of freshwa- ter lakes. Human conversion of atmospheric N into biologically useable forms, principally synthetic inorganic fertilizers, now matches the natural rate of biological N fixation from all the land surfaces of the earth. Both agriculture and the burning of fossil fuels contribute significantly to nonpoint flows of N to coastal waters, either as direct runoff or airborne pollutants. N from animal wastes that leaks directly to surface waters or is volatilized to the atmosphere as ammonia may be the largest single source of N that moves from agricultural operations into coastal waters. The National Research Council report recommended that, as a minimum goal, the nation should work to reverse nutrient should be taken to assure that the 40 percent of coastal areas now ranked as healthy do not develop symptoms of nutrient pollution in 10 percent of its degraded coastal systems by 2010 and 25 percent of them by 2020. Also, action should be taken to assure that the 40 percent of coastal areas now ranked as healthy do not develop symptoms of nutrient pollution. Meeting these goals will require an array of strategies and approaches tailored to specific regions and coastal ecosystems. There is an urgent need for development and testing of techniques that can reliably pinpoint the sources of N pollutants to an estuary. For some coastal systems, N removal during treatment of human sewage may be sufficient to reverse nutrient pollution. For most coastal systems, however, the solutions will be more complex and may involve controls on N compounds emitted during fossil fuel combustion as well as incentives to reduce over-fertilization of agricul- tural fields and nutrient pollution from animal wastes in livestock feedlot operations.

Alabama, California, Connecticut, Delaware, Florid↗

USGS2007

Remote sensing of tidal chlorophyll-a variations in estuaries

Simultaneous acquisition of surface chlorophyll-a concentrations for 39 samples from boats and Daedalus 1260 Multispectral Scanner data from a U-2 aircraft was conducted in the northern reaches of San Francisco Bay on 28 August 1980. These data were used to develop regression models for predicting surface chlorophyll-a concentrations over the study area for ebb-tide (8.40 a.m. P.D.T. (Pacific Daylight Time)) and flood-tide (3.10 p.m. P.D.T.) conditions. After selection of a single ‘best fitting’ model for both morning and afternoon data sets, the chlorophyll-a concentration was predicted for ebb and flood tide for the entire study area at approximately 40m × 40m resolution. The predicted spatial display of chlorophyll-a revealed a localized area of high phytoplankton biomass that has been inferred from field surveys and appears to be a common summer phenomenon. Knowledge of the distribution of phytoplankton and the location of this zone of high biomass is valuable in establishing management policies for this ecologically important estuary. Furthermore, the techniques used here may provide an alternative cost-effective method for assessing water-quality conditions and they may prove useful for studying spatial variations (patchiness) and seasonal variations in phytoplankton biomass in other estuaries and coastal waters.

California↗

USGS2009

Probability of Elevated Nitrate Concentrations in Groundwater in the Eagle River Watershed Valley-Fill Aquifer, Eagle County, North-Central Colorado, 2006-2007

This raster data set delineates the predicted probability of elevated nitrate concentrations in groundwater in the Eagle River watershed valley-fill aquifer, Eagle County, North-Central Colorado, 2006-2007. This data set was developed by a cooperative project between the U.S. Geological Survey, Eagle County, the Eagle River Water and Sanitation District, the Town of Eagle, the Town of Gypsum, and the Upper Eagle Regional Water Authority. This project was designed to evaluate potential land-development effects on groundwater and surface-water resources so that informed land-use and water management decisions can be made. This groundwater probability map and its associated probability maps was developed as follows: (1) A point data set of wells with groundwater quality and groundwater age data was overlaid with thematic layers of anthropogenic (related to human activities) and hydrogeologic data by using a geographic information system to assign each well values for depth to groundwater, distance to major streams and canals, distance to gypsum beds, precipitation, soils, and well depth. These data then were downloaded to a statistical software package for analysis by logistic regression. (2) Statistical models predicting the probability of elevated nitrate concentrations, the probability of unmixed young water (using chlorofluorocarbon-11 concentrations and tritium activities), and the probability of elevated volatile organic compound concentrations were developed using logistic regression techniques. (3) The statistical models were entered into a GIS and the probability map was constructed.

Data Series↗

USGS2009

Probability of Unmixed Young Groundwater (defined using chlorofluorocarbon-11 concentrations and tritium activities) in the Eagle River Watershed Valley-Fill Aquifer, Eagle County, North-Central Colorado, 2006-2007

This raster data set delineates the predicted probability of unmixed young groundwater (defined using chlorofluorocarbon-11 concentrations and tritium activities) in groundwater in the Eagle River watershed valley-fill aquifer, Eagle County, North-Central Colorado, 2006-2007. This data set was developed by a cooperative project between the U.S. Geological Survey, Eagle County, the Eagle River Water and Sanitation District, the Town of Eagle, the Town of Gypsum, and the Upper Eagle Regional Water Authority. This project was designed to evaluate potential land-development effects on groundwater and surface-water resources so that informed land-use and water management decisions can be made. This groundwater probability map and its associated probability maps were developed as follows: (1) A point data set of wells with groundwater quality and groundwater age data was overlaid with thematic layers of anthropogenic (related to human activities) and hydrogeologic data by using a geographic information system to assign each well values for depth to groundwater, distance to major streams and canals, distance to gypsum beds, precipitation, soils, and well depth. These data then were downloaded to a statistical software package for analysis by logistic regression. (2) Statistical models predicting the probability of elevated nitrate concentrations, the probability of unmixed young water (using chlorofluorocarbon-11 concentrations and tritium activities), and the probability of elevated volatile organic compound concentrations were developed using logistic regression techniques. (3) The statistical models were entered into a GIS and the probability map was constructed.

Data Series↗