National Water Information System Research Articles

Methyl Tertiary Butyl Ether (MTBE) and Other Volatile Organic Compounds (VOCs) in Public Water Systems, Private Wells, and Ambient Groundwater Wells in New Jersey Compared to Regulatory and Human-Health Benchmarks

Potential threats to drinking water and water quality continue to be a major concern in many regions of the United States. New Jersey, in particular, has been at the forefront of assessing and managing potential contamination of its drinking water supplies from hazardous substances. The purpose of the current analysis is to provide an up-to-date evaluation of the occurrence and detected concentrations of methyl tertiary butyl ether (MTBE) and several other volatile organic compounds (VOCs) in public water systems, private wells, and ambient groundwater wells in New Jersey based on the best available data, and to put these results into context with federal and state regulatory and human-health benchmarks. Analyses are based on the following three databases that contain water quality monitoring data for New Jersey: Safe Drinking Water Information System (SDWIS), Private Well Testing Act (PWTA), and National Water Information System (NWIS). For public water systems served by groundwater in New Jersey, MTBE was detected at a concentration ≥10 μg/L, ≥20 μg/L, and ≥70 μg/L at least once in 30 (2%), 21 (1.4%), and five (0.3%) of sampled systems from 1997 to 2011, respectively. For private wells in New Jersey, MTBE was detected at a concentration ≥10 μg/L, ≥20 μg/L, and ≥70 μg/L at least once in 385 (0.5%), 183 (0.2%), and 46 (0.05%) of sampled wells from 2001 to 2011, respectively. For ambient groundwater wells in New Jersey, MTBE was detected at a concentration ≥10 μg/L, ≥20 μg/L, and ≥70 μg/L at least once in 14 (2.1%), 9 (1.3%), and 4 (0.6%) of sampled wells from 1993 to 2012, respectively. Average detected concentrations of MTBE, as well as detected concentrations at upper-end percentiles, were less than corresponding benchmarks for all three datasets. The available data show that MTBE is rarely detected in various source waters in New Jersey at a concentration that exceeds the State's health-based drinking water standard or other published benchmarks, and there is no evidence of an increasing trend in the detection frequency of MTBE. Other VOCs, such as tetrachloroethylene (PCE), trichloroethylene (TCE), and benzene, are detected more often above corresponding regulatory or human-health benchmarks due to their higher detected concentrations in water and/or greater toxicity values. The current analysis provides useful data for evaluating the nature and extent of historical and current contamination of water supplies in New Jersey and potential opportunities for public exposures and health risks due to MTBE and other VOCs on a statewide basis. Additional forensic or forecasting analyses are required to identify the sources or timing of releases of individual contaminants at specific locations or to predict potential future water contamination in New Jersey.

Vulnerability of Recently Recharged Groundwater in Principle Aquifers of the United States To Nitrate Contamination

Recently recharged water (defined here as <60 years old) is generally the most vulnerable part of a groundwater resource to nonpoint-source nitrate contamination. Understanding at the appropriate scale the interactions of natural and anthropogenic controlling factors that influence nitrate occurrence in recently recharged groundwater is critical to support best management and policy decisions that are often made at the aquifer to subaquifer scale. New logistic regression models were developed using data from the U.S. Geological Survey's National Water-Quality Assessment (NAWQA) program and National Water Information System for 17 principal aquifers of the U.S. to identify important source, transport, and attenuation factors that control nonpoint source nitrate concentrations greater than relative background levels in recently recharged groundwater and were used to predict the probability of detecting elevated nitrate in areas beyond the sampling network. Results indicate that dissolved oxygen, crops and irrigated cropland, fertilizer application, seasonally high water table, and soil properties that affect infiltration and denitrification are among the most important factors in predicting elevated nitrate concentrations. Important differences in controlling factors and spatial predictions were identified in the principal aquifer and national-scale models and support the conclusion that similar spatial scales are needed between informed groundwater management and model development.

Identification of spatiotemporal nutrient patterns in a coastal bay via an integrated k-means clustering and gravity model

This study presents an integrated k-means clustering and gravity model (IKCGM) for investigating the spatiotemporal patterns of nutrient and associated dissolved oxygen levels in Tampa Bay, Florida. By using a k-means clustering analysis to first partition the nutrient data into a user-specified number of subsets, it is possible to discover the spatiotemporal patterns of nutrient distribution in the bay and capture the inherent linkages of hydrodynamic and biogeochemical features. Such patterns may then be combined with a gravity model to link the nutrient source contribution from each coastal watershed to the generated clusters in the bay to aid in the source proportion analysis for environmental management. The clustering analysis was carried out based on 1 year (2008) water quality data composed of 55 sample stations throughout Tampa Bay collected by the Environmental Protection Commission of Hillsborough County. In addition, hydrological and river water quality data of the same year were acquired from the United States Geological Survey's National Water Information System to support the gravity modeling analysis. The results show that the k-means model with 8 clusters is the optimal choice, in which cluster 2 at Lower Tampa Bay had the minimum values of total nitrogen (TN) concentrations, chlorophyll a (Chl-a) concentrations, and ocean color values in every season as well as the minimum concentration of total phosphorus (TP) in three consecutive seasons in 2008. The datasets indicate that Lower Tampa Bay is an area with limited nutrient input throughout the year. Cluster 5, located in Middle Tampa Bay, displayed elevated TN concentrations, ocean color values, and Chl-a concentrations, suggesting that high values of colored dissolved organic matter are linked with some nutrient sources. The data presented by the gravity modeling analysis indicate that the Alafia River Basin is the major contributor of nutrients in terms of both TP and TN values in all seasons. With this new integration, improvements for environmental monitoring and assessment were achieved to advance our understanding of sea-land interactions and nutrient cycling in a critical coastal bay, the Gulf of Mexico.

River Network Routing on the NHDPlus Dataset

AbstractThe mapped rivers and streams of the contiguous United States are available in a geographic information system (GIS) dataset called National Hydrography Dataset Plus (NHDPlus). This hydrographic dataset has about 3 million river and water body reaches along with information on how they are connected into networks. The U.S. Geological Survey (USGS) National Water Information System (NWIS) provides streamflow observations at about 20 thousand gauges located on the NHDPlus river network. A river network model called Routing Application for Parallel Computation of Discharge (RAPID) is developed for the NHDPlus river network whose lateral inflow to the river network is calculated by a land surface model. A matrix-based version of the Muskingum method is developed herein, which RAPID uses to calculate flow and volume of water in all reaches of a river network with many thousands of reaches, including at ungauged locations. Gauges situated across river basins (not only at basin outlets) are used to automatically optimize the Muskingum parameters and to assess river flow computations, hence allowing the diagnosis of runoff computations provided by land surface models. RAPID is applied to the Guadalupe and San Antonio River basins in Texas, where flow wave celerities are estimated at multiple locations using 15-min data and can be reproduced reasonably with RAPID. This river model can be adapted for parallel computing and although the matrix method initially adds a large overhead, river flow results can be obtained faster than with the traditional Muskingum method when using a few processing cores, as demonstrated in a synthetic study using the upper Mississippi River basin.

Use of standard vocabulary services in validation of water resources data described in XML

The machine readable encoding language XML is used in water informatics to describe resources and observational data, such as the Water Data Transfer Format (WDTF). WDTF is part of an Australian initiative, established by the Australian Bureau of Meteorology in collaboration with CSIRO, to collate water resources data from multiple data providers into a national water information system. A common way of validating XML data is by defining a schema using XML Schema Definition language (XSD) and performing validation using standard XSD tools. However, XSD validation lacks the ability to perform content validation to assert context, domain and organizational rules such as soft-typing, co-constraints, and code-list or vocabulary checking, which is required in the validation of WDTF data. In this paper, we describe a validation service for validating water resources data encoded in WDTF, which combines structural and content validation. We also describe the use of a vocabulary service with the WDTF validation service to perform code-list and vocabulary checking.

Estimation of Suspended-Sediment Concentration From Total Suspended Solids and Turbidity Data for Kentucky, 1978-19951

Williamson, Tanja N. and Charles G. Crawford, 2011. Estimation of Suspended-Sediment Concentration From Total Suspended Solids and Turbidity Data for Kentucky, 1978-1995. Journal of the American Water Resources Association (JAWRA) 47(4):739-749. DOI: 10.1111/j.1752-1688.2011.00538.x Abstract: Suspended sediment is a constituent of water quality that is monitored because of concerns about accelerated erosion, nonpoint contamination of water resources, and degradation of aquatic environments. In order to quantify the relationship among different sediment parameters for Kentucky streams, long-term records were obtained from the National Water Information System of the U.S. Geological Survey. Suspended-sediment concentration (SSC), the parameter traditionally measured and reported by the U.S. Geological Survey, was statistically compared to turbidity and total suspended solids (TSS), two parameters that are considered surrogate data. A linear regression of log-transformed observations was used to estimate SSC from TSS; 72% of TSS observations were less than coincident SSC observations; however, the estimated SSC values were almost as likely to be overestimated as underestimated. The SSC-turbidity relationship also used log-transformed observations, but required a nonlinear, breakpoint regression that separated turbidity observations ≤6 nephelometric turbidity units. The slope for these low turbidity values was not significantly different than zero, indicating that low turbidity observations provide no real information about SSC; in the case of the Kentucky sediment record, this accounts for 30% of the turbidity observations.

Evaluation of Potential Changes in Groundwater Quality in Response to CO2 Leakage from Deep Geologic Storage

Concern has been expressed that carbon dioxide (CO2) leaking from deep geological storage could adversely impact water quality in overlying potable aquifers by mobilizing hazardous trace elements. In this article, we present a systematic evaluation of the possible water quality changes in response to CO2 intrusion into aquifers currently used as sources of potable water in the United States. The evaluation was done in three parts. First, we developed a comprehensive geochemical model of aquifers throughout the United States, evaluating the initial aqueous abundances, distributions, and modes of occurrence of selected hazardous trace elements in a large number of potable groundwater quality analyses from the National Water Information System (NWIS) database. For each analysis, we calculated the saturation indices (SIs) of several minerals containing these trace elements. The minerals were initially selected through literature surveys to establish whether field evidence supported their postulated presence in potable water aquifers. Mineral assemblages meeting the criterion of thermodynamic saturation were assumed to control the aqueous concentrations of the hazardous elements at initial system state as well as at elevated CO2 concentrations caused by the ingress of leaking CO2. In the second step, to determine those hazardous trace elements of greatest concern in the case of CO2 leakage, we conducted thermodynamic calculations to predict the impact of increasing CO2 partial pressures on the solubilities of the identified trace element mineral hosts. Under reducing conditions characteristic of many groundwaters, the trace elements of greatest concern are arsenic (As) and lead (Pb). In the final step, a series of reactive-transport simulations was performed to investigate the chemical evolution of aqueous As and Pb after the intrusion of CO2 from a storage reservoir into a shallow confined groundwater resource. Results from the reactive-transport model suggest that a significant increase of aqueous As and Pb concentrations may occur in response to CO2 intrusion, but that the maximum concentration values remain below or close to specified maximum contaminant levels (MCLs). Adsorption/desorption from mineral surfaces may strongly impact the mobilization of As and Pb.

Regional variations in water quality and relationships to soil and bedrock weathering in the southern Sacramento Valley, California, USA

Regional patterns in ground- and surface-water chemistry of the southern Sacramento Valley in California were evaluated using publicly available geochemical data from the US Geological Survey’s National Water Information System (NWIS). Within the boundaries of the study area, more than 2300 ground-water analyses and more than 20,000 surface-water analyses were available. Ground-waters from the west side of the Sacramento Valley contain greater concentrations of Na, Ca, Mg, B, Cl and SO 4 , while the east-side ground-waters contain greater concentrations of silica and K. These differences result from variations in surface-water chemistry as well as from chemical reactions between water and aquifer materials. Sediments that fill the Sacramento Valley were derived from highlands to the west (the Coast Ranges) and east (the Sierra Nevada Mountains), the former having an oceanic provenance and the latter continental. These geologic differences are at least in part responsible for the observed patterns in ground-water chemistry. Thermal springs that are common along the west side of the Sacramento Valley appear to have an effect on surface-water chemistry, which in turn may affect the ground-water chemistry.

Identification of thermodynamic controls defining the concentrations of hazardous elements in potable ground waters and the potential impact of increasing carbon dioxide partial pressure

Abstract Concern has been expressed that carbon dioxide leaking from deep storage reservoirs could adversely impact water quality in overlying potable aquifers by mobilizing hazardous elements present in the aquifer rocks to the extent that their concentrations might exceed Maximum Contaminant Levels (MCLs). To evaluate this issue, 38,000 ground water quality analyses from aquifers throughout the United States, each containing one or more analyses for As, Ba, Cd, Hg, Pb, Sb, Se, U or Zn, were retrieved from the Unites States National Water Information System (NWIS). The analyses were used to calculate the saturation indices (SIs) of all identified and thermodynamically characterized minerals containing the listed elements as essential components. These minerals were initially selected through literature surveys to establish whether field evidence supported their postulated presence in potable water aquifers. SI frequency histograms were plotted to evaluate whether these minerals are at saturation in NWIS ground waters (i.e., they show modes at SI 0). Mineral assemblages meeting the criterion of thermodynamic saturation were assumed to control the aqueous concentrations of the hazardous elements at initial system state as well as at elevated CO 2 partial pressure caused by the ingress of leaking CO 2 . The impact on the identified mineral solubilities of increasing CO 2 partial pressures was then predicted over the range from −4 to +1 (i.e., 10 −4 ≤P(CO 2 ) in bar ≤10). Under reducing conditions (characteristic of most ground waters), the most serious problem resulting from intrusion of CO 2 into shallow groundwater may arise through enhanced dissolution of pyrite and solubilization of arsenic. At the highest P(CO 2 ) assumed in our study, Ba, Pb and Zn may also approach or exceed regulatory concentration limits. Of the remaining elements, the MCLs of Cd, and Sb are unlikely to be exceeded, and Hg, Se and U concentrations are unaffected by CO 2 intrusion.

Availability and coverage of hydrologic data in the US geological survey National Water Information System (NWIS) and US Environmental Protection Agency Storage and Retrieval System (STORET)

The need for a unified and improved data access system for the nation’s vast hydrologic data holdings has increased over the past few years as researchers strive for better understanding the human impact on the nation’s water cycle. Large mission oriented data repositories such as the USGS’ National Water Information System (NWIS) and EPA’s Storage and Retrieval System (EPA STORET) play a crucial role in providing a substantial amount of the nationwide coverage, however they do differ regionally in terms of coverage (parameters) and geospatial data density. Besides the differences in geographic distribution, repositories tend to undergo changes in mission statements and as such have different foci in their data collection activities that change as time progresses. This paper places the two water information systems next to each in an attempt to work out the differences in terms of coverage and content and how they complement each other when overlaid. This is done through the use of a number the CUAHSI Hydrologic Information Systems components, namely a web-service suite called WaterOneFlow that permits interrogation of the available data content of a national water metadata catalogue into which these two information systems have been integrated.

Bringing Water Data Together

We are living through an information revolution. We are instantly connected to information and services through the internet, and communicate through e-mail with colleagues spread all over the globe, without regard to distance or their computer system. How can the power of this information revolution be brought to bear on water resources? This editorial presents some perspectives I have derived from my service as leader of the Consortium of Universities for the Advancement of Hydrologic Science, Inc. CUAHSI Hydrologic Information System HIS project, a Nation Science Foundation NSF -supported effort to improve hydrologic science through better data access and organization at the nation’s universities. The circulation of the waters of the earth through the hydrologic cycle is a very complex phenomenon. Many agencies and individuals collect water observations data on streamflow, water quality, groundwater levels, precipitation, snow conditions, and climate. The largest repository of such data in the United States is the United States Geological Survey USGS National Water Information System NWIS , which contains information from about 1.6 million sites for streamflow, water quality, and groundwater. Other large federal repositories of water observations data are the Environmental Protection Agency EPA Storet Storage and Retrieval for water quality, the National Climatic Data Center’s Climate Data Online, and the United States Department of Agriculture USDA -National Resources Conservation Service NRCS Snotel and Soil Climate Analysis Network SCAN databases. Agencies such as the Bureau of Reclamation and the Corps of Engineers store water operations data at reservoirs and other facilities. This panoply of federal data is augmented by similar data collected by state and local water agencies. Academic and research investigators collect data for individual research projects, and contribute significantly to subjects, such as aquatic biology and continuous monitoring of water quality, that are not the traditional focus of the large water agencies. The aggregation of all this water observations information defines the historical record of the water conditions of the nation. The task of assembling all the relevant information for a particular purpose in a chosen geographic region is greatly facilitated by the publication of much of the data on Web sites. However, every organization follows its own method in constructing its Web site and formatting the data presented there, so it still requires a great deal of effort to discover, learn, and operate all these various Web data sources. And, much of the data collected by academic and research investigators is no longer accessible once research studies are completed. Water conditions have been measured in the nation at several million locations, but no comprehensive window on water data exists. The growth of information sharing across the internet has led to the definition of standards for communication among computers. One of these standards is the HyperText Markup Language HTML used for communication of information visible in Web

QUANTIFYING PERIODIC, STOCHASTIC, AND CATASTROPHIC ENVIRONMENTAL VARIATION

Environmental variation plays a central role in regulating processes at all levels of ecological organization. Environmental data (e.g., temperature, rainfall, stream discharge, water chemistry) are typically easy to collect in large quantity, a requirement for many data-hungry time series tools. Unfortunately, these data are very rarely used effectively in ecology. Here we address this problem by outlining a suite of tools that can be used to quantify periodic, stochastic, and catastrophic variation in environmental conditions. We illustrate the application of these tools using long-term records of average daily discharge in 105 streams and rivers maintained by the U.S. Geological Survey on the NWIS (National Water Information System) web site. Specifically, we apply Fourier analysis to estimate the periodic (seasonal) and stochastic (interannual) components of variation in discharge. We then estimate the temporal autocorrelation structure of stochastic variation (i.e., noise color) in daily flows for each stream. Noise color corresponds to storage of atmospheric inputs within the watershed. Finally, we extend Fourier analysis in two ways to provide estimates of annual noise color and catastrophic variation in both high- and low-flow events. Our analysis provides three compelling insights about the nature of variation in discharge experienced by stream biota. First, seasonal variation in discharge is higher than interannual variation in most streams, although some streams can be classified as aseasonal. Second, daily noise color varies from slightly pink to black, reflecting storage of water at a wide range of temporal scales. By contrast, annual noise color is nearly uniformly white across our sample of streams, reflecting nearly zero storage of atmospheric inputs across years. Third, catastrophic variation in high flows is of greater magnitude than in low flows for many of our 105 streams, yet low-flow variation is surprisingly high. This result suggests that low-flow events may be underappreciated in stream ecology. We close by suggesting how these methods could be applied to other environmental variables (hourly temperature, monthly rainfall). Periodic, stochastic, and catastrophic sources of variation contribute to environmental stress, process noise, and disturbance, respectively. Thus, the tools we present here provide a means for estimating numerical values associated with these ecological concepts and facilitate comparative studies conducted across gradients of one or more of these sources of variation.

A first approach to web services for the National Water Information System

A wealth of freely available hydrologic data are provided by governmental organizations including in situ observations, geospatial data sets, remote sensing products, and simulation model output. Despite having access to this information, much of the data remain underutilized in the hydrologic sciences due in part to the time required to access, obtain, and integrate data from different sources. Web services offer a means for sharing hydrologic data more openly by providing a standard protocol for machine-to-machine communication. We have used this new technology to create a machine accessible interface for the National Water Information System (NWIS), an online repository of historical and real-time streamflow, water-quality, and ground water level observations maintained by the United States Geological Survey (USGS). These services provide a middle-layer of abstraction between the NWIS database and hydrologic analysis systems, allowing such analysis systems to proxy the NWIS server for on-demand data access. We intentionally designed the services to be generic and applicable to other hydrologic databases, in order to provide interoperability between disparate data sources. Performance tests showed that, for time series with less than 1000 observations, the web services layer added minimal overhead in terms of data response time, and development of an example client application for time series visualization highlighted some of the benefits and costs of using web services for data access.

Seasonal variation of arsenic concentration in wells in Nevada

The issue of seasonal arsenic measurement variability poses consequences regarding the interpretation and frequency of well water measurements for both public health research and surveillance. In this study, we evaluated seasonal variability in arsenic concentration in 356 wells in western Nevada. River flow data obtained from US Geological Survey National Water Information System were used to classify seasons as wet or dry, and mean differences in arsenic well concentrations measured during these seasons were compared. Arsenic concentrations in these wells averaged 72.9 μ g / L (range, non-detect to 3000 μ g / L ). The mean difference in arsenic concentrations between the wet and dry seasons was - 3.3 μ g / L ( p = 0.78 ; average percent difference=2.3%). Eighty wells (22%) had higher arsenic concentrations in the wet season, 75 wells (21%) had higher arsenic concentrations in the dry season and no difference was seen in 201 wells (56%). The mean differences in wells with arsenic levels of 0–10, 11–50, 51–200, > 200 μ g / L were - 1.4 μ g / L ( p = 0.43 ) , 9.2 μ g / L ( p = 0.36 ) , 15.1 μ g / L ( p = 0.30 ) , and - 49.9 μ g / L ( p = 0.59 ) . In summary, although changes in arsenic concentrations were seen in some wells, clear trends in arsenic concentration over time were not associated with the wet and dry seasons. These findings provide evidence that, in our study area as a whole, little seasonal variability occurs in arsenic concentrations, and repeated assessments of arsenic concentrations based on season might add little value to the accuracy of health effects research or public health surveillance.

Sustentabilidade ambiental da água consumida no Município do Rio de Janeiro, Brasil

To propose an urban water sustainability index based on indicators that may serve as a foundation for developing planned actions concerning water resources. Eleven indicators (covering aspects of water and sewage) were selected based on the parameters of Brazil's National Water and Sanitation Information System (Sistema Nacional de Informação sobre Saneamento) for the years 2000 and 2001. A score and a weight were assigned to each indicator. Based on that, the urban water sustainability index (UWSI) was calculated, using the formula UWSI = product (I(i)(pi)), where I(i) is the score attributed to each indicator i, ranging from 0 to 100, and p(i) is the weight for each indicator sigma(i=1)(n) p(i) = 1, where n is the number of indicators considered). The lowest water quality is indicated by an index value of 0, and the best by an index value of 100. The urban water sustainability index for the city of Rio de Janeiro was 58.99 in 2000, and it rose to 59.57 in 2001, indicating water of good quality in both those years. The improvement in the quality of the water resources between 2000 and 2001 in the city of Rio de Janeiro is possibly the result of the implementation, in the 1990s, of an environmental management program in the Rio de Janeiro region. Environmental planning that includes rational use of water resources and methods to prevent their destruction is crucial to sustaining society.

The Unusual Channel Resistance of the Texas Hill Country and its Effect on Flood Flow Predictions

The importance of hydraulic roughness estimates in modeling river flow cannot be overstated. Spatial and temporal variation of flow resistance can have a dramatic effect on the prediction of floodplain width, depth, and other hydraulic properties. The Texas Hill Country, a physiographic region of uplifted and differentially eroded limestone in south-central Texas, is the site of considerably heterogeneous fluvial forms and processes. Predictions of the spatial extent of floods in this area are difficult given this topographic and fluvial heterogeneity. In this report, we present a new method to extract spatial maps of hydraulic roughness using channel geometry and newly accessible USGS National Water Information System (NWIS) data. We use these data to construct maps of hydraulic roughness at different discharges and to test roughness prediction methods suggested by previous authors. Our method for extracting roughness values is general and should be applicable in most areas of the United States. The patterns of hydraulic resistance around the Texas Hill Country and through its eastern boundary, the Balcones Escarpment, are spatially diverse, ranging from n ≅ 0.016 to 0.213, and no simple spatial pattern of roughness exists. The most unexpected finding is the high values of Manning's roughness value (n) in most areas of the Hill Country, with n values often two or three times greater (n ≅ 0.04-0.06) than what would be expected using common n-estimation techniques (n ≅ 0.01-0.02). This simple finding is of practical importance because the too-low values of Manning's roughness are almost certainly translated into floodplain maps as too narrowly delineated floodplains.

A land information system for Turkey—a key to the country's sustainable development

This paper describes the development by the General Directorate of Rural Services (GDRS) of a land information system for Turkey, namely the National Soil and Water Information System. It is of great significance for the modern state of Turkey as, prior to its establishment in 1999 under the Turkish Agricultural Research Project, there was no definitive, national technological information resource underpinning land and water resource management. The system will support the operational and research responsibilities of the Directorate in combating some of the current environmental concerns in Turkey, including wind and water erosion, waterlogging, sodicity and salination of the soil resource. The complex process of compiling the first national digital soil map will be among the initial tasks, as well as establishing a national infrastructure for distributing the information amongst GDRS managers and scientists. With the proposed accession of the Turkish Republic to the European Union, alignment of the National Soil and Water Information System with European standards and protocols will prove to be an important facet of its ongoing development.

USGS introduces water data Web site

The U.S. Geological Survey (USGS) has been collecting data about the nation's water for more than a century.Now, the survey's new National Water Information System, or NWISWeb, provides online users—including scientists, water managers, emergency managers, and recreational water users—with access to hundreds of millions of pieces of archival and real‐time data.

A WWW and Spreadsheet-Based Exercise on Flood-Frequency Analysis

Most current classroom or laboratory exercises on flood-frequency analysis use small synthetic data sets and hand-plotting methods to estimate the probability of river flooding of a given magnitude. The availability of the USGS's National Water Information System on the World-Wide Web allows students to download discharge data from many rivers in the US and perform flood-frequency analysis on large data sets. Subsets of the data can also be easily investigated. The exercise described here provides for learning several skills: the student queries the database, downloads the record to a desktop computer, performs calculations on it, makes plots using a spreadsheet program, and interprets the results in the light of probability analysis.

Use of Geographic Information System to Display Water-Quality Data from San Juan Basin: ABSTRACT

The ARC/INFO geographic information system is creating thematic maps of the San Juan basin as part of the USGS Regional Aquifer-System Analysis program. (Use of trade names is for descriptive purposes only and does not constitute endorsement by the US Geological Survey.) Maps created by a Prime version of ARC/INFO, to be published in a series of Hydrologic Investigations Atlas reports for selected geologic units, will include outcrop patters, water-well locations, and water-quality data. The San Juan basin study area, encompassing about 19,400 mi{sup 2}, can be displayed with ARC/INFO at various scales; on the same scale, generated water-quality maps can be compared and overlain with other maps such as potentiometric surface and depth to top of a geologic or hydrologic unit. Selected water-quality and well data (including latitude and longitude) are retrieved from the USGS National Water Information System data base for a specified geologic unit. Data are formatted by Fortran programs and read into an INFO data base. Two parallel files - an INFO file containing water-quality data and well data and an ARC file containing the site coordinates - are joined to form the ARC/INFO data base. A file containing a series of commands using Prime's Commandmore » Procedure language is used to select coverage, display, and position data on the map. Data interpretation is enhanced by displaying water-quality data throughout the basin in combination with other hydrologic and geologic data.« less