bluuebunny/crossref_metadata_2025_split huggingface dataset:
WATER QUALITY TRENDS AT INFLOWS TO EVERGLADES NATIONAL PARK1
Authors: Walker William W. 
Published: June 2007

ABSTRACT: Water quality data collected at inflows to Everglades National Park (ENP) are analyzed for trends using the seasonal Kendall test (Hirsch et al., 1982; Hirsch and Slack, 1984). The period of record is 1977–1989 for inflows to Shark River Slough and 1983–1989 for inflows to Taylor Slough and ENP's Coastal Basin. The analysis considers 20 water quality components, including nutrients, field measurements, inorganic species, and optical properties.Significant (p<0.10) increasing trends in total phosphorus concentration are indicated at eight out of nine stations examined. When the data are adjusted to account for variations in antecedent rainfall and water surface elevation, increasing trends are indicated at seven out of nine stations. Phosphorus trend magnitudes range from 4 percent/year to 21 percent/year Decreasing trends in the Total N/P ratio are detected at seven out of nine stations. N/P trend magnitudes range from ‐7 percent/year to ‐15 percent/year. Trends in water quality components other than nutrients are observed less frequently and are of less importance from a water‐quality‐management perspective. The apparent nutrient trends are not explained by variations in marsh water elevation, antecedent rainfall, flow, or season.
EXPERIMENTAL EVALUATION OF MULTIPLE CRITERIA DECISION MODELS FOR APPLICATION TO WATER RESOURCES PLANNING1
Authors: Goicoechea Ambrose , Stakhiv Eugene Z. , Li Fu 
Published: June 2007

ABSTRACT: A research project was undertaken for the U.S. Army Corps of Engineers to determine the relative utility and effectiveness of four well‐known multicriteria decision making (MCDM) models for applications in realistic water resources planning settings. A series of experiments was devised to examine the impact of rating and ranking procedures on the decision making behavior of users (e.g., planners, managers, analysts, etc.) when faced with situations involving multiple evaluation criteria and numerous alternative planning projects. The four MCDM models tested were MATS‐PC, EXPERT CHOICE, ARIADNE, and ELECTRE.Two groups of analysts and decision makers were tested. One group consisted of experienced U.S. Army Corps planners, while the other was comprised of graduate students. Based on a series of nonparametric statistical tests, the results identified EXPERT CHOICE as the preferred MCDM model by both groups based largely on ease of use and understandability. ARIADNE fostered the largest degree of agreement within and among the two groups of individuals tested. The tests also lend support to the claim that rankings are not affected significantly by the choice of decision maker (i.e., who uses any of these MCDM models) or which of these four models is used.
ACID PRECIPITATION AND WEATHERING BY ORGANIC ACIDS IN LABRAI)OR LAKE BASINS1
Authors: Clair Thomas A. 
Published: June 2007

ABSTRACT: Thirty‐five lakes in southern Labrador sampled in 1981 were resampled in 1989 and water chemistry values were compared between visits. Results showed higher pH, specific conductance, acid neutralization capacity, color, and base cations values in 1989, though sulfate, the ion most likely to reflect acid precipitation impacts, did not vary. The major ion changes measured were probably due to natural hydrological variations and not to changes in acid inputs.Results from the 1989 data showed a slight, but significant, decrease in water sulfate concentration trend from western to eastern Labrador, though most values, even in the western portion of the study area, fell close to the values considered “background” by Brakke et at. (1989). Base cation concentrations exceeded those which could be predicted from weathering by carbonic and bicarbonic acid. Assuming that little weathering is generated by acid precipitation in this region, the excess cations measured are probably a result of bedrock dissolution from organic acids generated by plant decomposition. Calculations showed that organic acid effect could be responsible for 9 to 52 percent of total weathering in the study basins.
APPLICATION OF THE GREEN‐AMPT INFILTRATION EQUATION TO WATERSHED MODELING1
Authors: James Wesley P. , Warinner John , Reedy Michael 
Published: June 2007

ABSTRACT: A computer model was developed, based on the Green‐Ampt infiltration equation, to computed rainfall excess for a single precipitation event. The model requires an estimate of parameters related to hydraulic conductivity, wetting front section, and fillable porosity of the soil layers. Values of parameters were estimated from soil textural averages or regression equations based on percent sand, percent clay, and porosity. Average values of effective porosity and wetting front suction were largely acceptable due to the relatively low variability and low model sensitivity to the parameters. Hydraulic conductivity was the most erratic constituent of the loss rate computation due to the high variability and the high sensitivity of the computed infiltration to the parameter.The performance of the Green‐Ampt infiltration model was tested through a comparison with the SCS curve number procedure. Seven watersheds and 23 storms with precipitation of one inch or greater were used in the comparison. For storms with less than one inch of rainfall excess, the SCS curve number procedure generally gave the best results; however, for six of the seven storms with precipitation excess greater than one inch, the Green‐Ampt procedure delivered better results. In this comparison, both procedures used the same initial abstractions.The separation of rainfall losses into infiltration, interception, and surface retention is, in theory, an accurate method of estimating precipitation excess. In the second phase of the study using nine watersheds and 39 storms, interception and surface retention losses were computed by the Horton equations. Green‐Ampt and interception parameters were estimated from value sin the literature, while the surface retention parameter was calibrated so that the computed runoff volumes matched observed volumes. A relationship was found between the surface retention storage capacity and the 15‐day antecedent precipitation index, month of year, and precipitation amount.
IDENTIFICATION OF CRITICAL NONPOINT POLLUTION SOURCE AREAS USING GEOGRAPHIC INFORMATION SYSTEMS AND WATER QUALITY MODELING1
Authors: Tim U. S. , Mostaghimi S. , Shanholtz V O. 
Published: June 2007

ABSTRACTn integrated approach coupling water quality computer simulation modeling with a geographic information system (GIS) was used to delineate critical areas of nonpoint source (NPS) pollution at the watershed level. Two simplified pollutant export models were integrated with the Virginia Geographic Information System (VirGIS) to estimate soil erosion, sediment yield, and phosphorus (P) loading from the Nomini Creek watershed located in Westmoreland County, Virginia.On the basis of selected criteria for soil erosion rate, sediment yield, and P loading, model outputs were used to identily watershed areas which exhibit three categories (low, medium, high) of non‐point source pollution potentials. The percentage of the watershed area in each category, and the land area with critical pollution problems were also identified. For the 1505‐ha Nomini Creek watershed, about 15, 16, and 21 percent of the watershed area were delineated as sources of critical soil erosion, sediment, and phosphorus pollution problems, respectively. In general, the study demonstrated the usefulness of integrating GIS with simulation modeling for nonpoint source pollution control and planning. Such techniques can facilitate making priorities and targeting nonpoint source pollution control programs.
COMPUTING THE RISKS ASSOCIATED WITH WASTELOAD) ALLOCATION MODELING1
Authors: Warwick J.J. , Roberts L. A. 
Published: June 2007

ABSTRACT: The risks associated with a traditional wasteload allocation (WLA) analysis were quantified with data from a recent study of the Upper Trinity River (Texas). Risk is define here as the probability of failing to meet an established in‐stream water quality standard. The QUAL‐TX dissolved oxygen (DO) water quality model was modified to a Monte Carlo framework. Flow augmentation coding was also modified to allow an exact match to be computed between the predicted and an established DO concentration standard, thereby providing an avenue for linking input parameter uncertainty to the assignment of a wasteload permit (allowable mass loading rate).Monte Carlo simulation techniques were employed to propagate input parameter uncertainties, typically encountered during WLA analysis, to the computed effluent five‐day carbonaceous biochemical oxygen demand requirements for a single major wastewater treatment plant (WWTP). The risk of failing to meet an established in‐stream DO criterion may be as high as 96 percent. The uncertainty associated with estimation of the future total Kjeldahl nitrogen concentration for a single tributary was found to have the greatest impact on the determination of allowable WWTP loadings.
A REVIEW OF APPLICATION ISSUES OF THE METROPOLITAN WATER DISTRICT‐MAIN WATER FORECASTING SYSTEM1
Authors: Thompson James G. , Parker Michael , Templin William , Reynolds Robert R. 
Published: June 2007

ABSTRACT: This paper reviews the processes that occurred during an application of the Metropolitan Water District (MWD)‐MAIN water use forecasting system for the City of Salinas, California. The review includes an analysis of sources of available data, methods for estimating input data, calibration, and verification of the MWD‐MAIN System, and an evaluation of the reliability of system output. We found that inexperienced users can have difficulty understanding the level of skill, knowledge, and amount of data that are required to produce reliable forecasts.Some of the issues associated with application of the MWD‐MAIN System include the following:

All input data needed for accurate forecasts simply are not available for many cities and towns.
The data requirements are more extensive than many users anticipate.
Substantial requirements for manipulation of input data produces opportunity for error that creates major time demands in troubleshooting.
Calibration and verification for specific uses can be substantially more difficult than is readily apparent from the guidance manual.
Independent validity checks need to be done to validate system output.
If specified calibrating procedures do not produce reasonable results, reestimating slope coefficients is an option, but this requires resources and expertise that can easily exceed the limits of most users.

These are problems typical of most complex models. Reviews such as this can help users to appreciate the level of data required, and to use the MWD‐MAIN System in a more effective and efficient manner.
EFFECTS OF CLIMATE CHANGE ON WATER RESOURCES IN THE DELAWARE RWER BASIN1
Authors: Wolock David M. , McCabe Gregory J. , Tasker Gary D. , Moss Marshall E. 
Published: June 2007

ABSTRACT: The effects of potential climate change on water resources in the Delaware River basin were determined. The study focused on two important water‐resource components in the basin: (1) storage in the reservoirs that supply New York City, and (2) the position of the salt front in the Delaware River estuary. Current reservoir operating procedures provide for releases from the New York City reservoirs to maintain the position of the salt front in the estuary downstream from freshwater intakes and ground‐water recharge zones in the Philadelphia metropolitan area.A hydrologic model of the basin was developed to simulate changes in New York City reservoir storage and the position of the salt front in the Delaware River estuary given changes in temperature and precipitation. Results of simulations indicated that storage depletion in the New York City reservoirs is a more likely effect of changes in temperature and precipitation than is the upstream movement of the salt front in the Delaware River estuary. In contrast, the results indicated that a rise in sea level would have a greater effect on movement of the salt front than on storage in the New York City reservoirs. The model simulations also projected that, by decreasing current mandated reservoir releases, a balance can be reached wherein the negative effects of climate change on storage in the New York City reservoirs and the position of the salt front in the Delaware River estuary are minimized. Finally, the results indicated that natural variability in climate is of such magnitude that its effects on water resources could overwhelm the effects of long‐term trends in precipitation and temperature.
SOUTH PLATTE RIVER BASIN ‐ COLORADO, NEBRASKA, AND WYOMING1
Authors: Dennehy Kevin F. , Litke David W , Tate Cathy M. , Heiny Janet S. 
Published: June 2007

ABSTRACT: The South Platte River Basin was one of 20 study units selected in 1991 for investigation under the U.S. Geological Survey's National Water‐Quality Assessment (NAWQA) program. One of the initial tasks undertaken by the study unit team was to review the environmental setting of the basin and assemble ancillary data on natural and anthropogenic factors in the basin. The physical, chemical, and biological quality of the water in the South Platte River Basin is explicitly tied to its environmental setting. The resulting water quality is the product of the natural conditions and human factors that make up the environmental setting of the basin.This description of the environmental setting of the South Platte River Basin and its implications to the water quality will help guide the design of the South Platte NAWQA study. Natural conditions such as physiography, climate, geology, and soils affect the ambient water quality while anthropogenic factors such as water use, population, land use and water‐management practices can have a pronounced effect on water quality in the basin. The relative effects of mining, urban, and agricultural land‐ and water‐uses on water‐quality constituents are not well understood. The interrelation of the surface‐water and ground‐water systems and the chemical and biological processes that affect the transport of constituents needs to be addressed. Interactions between biological communities and the water resources also should be considered. The NAWQA program and the South Platte River Basin study will provide information to minimize existing knowledge gaps, so that we may better understand the effect these natural conditions and human factors have on the water‐quality conditions in the basin, now and in the future.
SUBSTATE INSTITUTIONAL INNOVATION FOR MANAGING LAKES AND WATERSHEDS: A WISCONSIN CASE STUDY1
Authors: Nakamura Liane , Born Stephen M. 
Published: June 2007

ABSTRACT: Since the 1970s, there has been extensive experimentation with new approaches to water and land resources management at the state and local levels. There is a critical need to document, assess, and synthesize lessons learned from the nation's recent experience with subnational institutional changes in environmental management. This paper examines institutional changes aimed at more integrated water and related resources management at the substate level of government. We describe innovative institutional changes in a case study of Dane County, Wisconsin, and assess the implementation and preliminary consequences of these changes.Dissatisfaction with watershed and lake management results and perceptions of institutional inadequacy led to significant changes in the structure and rules for county resources management. A new entity was created to focus watershed management responsibilities. The scope of authority and powers were expanded. However, these changes all occurred within the framework of a general purpose unit of government. The new institutional arrangements have achieved a number of milestones, although it is premature to fully assess resource outcomes. The substantive changes, implementation tactics, and overall experience in Dane County's reforms ‐ especially with regard to addressing intergovernmental tensions and decentralized management, limited authorities and funding, and public and constituency support ‐ have useful implications for other substate efforts at more comprehensive and integrated water resources management.
USE OF WATER FROM THE ANCIENT MAKKAH GALLERIES FOR IRRIGATION1
Authors: Abu‐Rizaiza Omar S. , Mohorjy Abdullah M. 
Published: June 2007

ABSTRACT: Due to the spread of Islam in the seventh century the number of pilgrims to the City of Makkah increased sharply, resulting in an acute water shortage. To solve this problem, galleries were built to collect water from the upstream of Wadi Naaman and transfer it to Makkah.Expansion of Makkah and the absence of any mapping of the galleries have resulted in the destruction of a part of the galleries. This caused a discontinuity of flow in the galleries and, consequently, the ground water table is rising at a rate of 0.48 m/yr, causing environmental problems. Research was conducted to rehabilitate the destructed part of the galleries, and to find an appropriate use for the ground water. The study found that the quality of the ground water is suitable for landscaping purposes, that is, for the irrigation of trees and ornamental plants.
FUZZY DECISION MAKING IN GROUND WATER NITRATE RISK MANAGEMENT1
Authors: Lee Yong W. , Dahab Mohamed F , Bogardi Istuan 
Published: June 2007

ABSTRACT: Ground water nitrate contamination is widespread in the United States and especially prevalent in agriculture‐intensive areas such as the Midwest. To reduce human health risks (i.e., methemoglobinemia and cancer risks) from nitrates in ground water supplies, several nitrate risk‐management strategies can be developed based on acceptable levels of human health risks, the reasonableness of the cost required for risk reduction, and the technical feasibility of nitrate‐control methods. However, due to a lack of available information, assessing risk, cost, and technical feasibility contains elements of uncertainty.In this paper, a nitrate risk‐management methodology using fuzzy sets in combination with a multicriterion decision‐making (MCDM) technique is developed to assist decision makers in evaluating, with uncertain information, possible regulatory actions along with the various nitrate risk‐management strategies in order to determine an appropriate strategy. The methodology is illustrated using data from a community with a nitrate water‐quality problem.
HYDROLOGIC MODELING OF LAND PROCESSES IN PUERTO RICO USING REMOTELY SENSED DATA1
Authors: Cruise J. F. , Miller R. L. 
Published: June 2007

ABSTRACT: An integrated, multi‐disciplinary effort to model land processes affecting Mayaguez Bay in western Puerto Rico is described. A modeling strategy was developed to take advantage of remotely sensed data. The spatial, interannual, and seasonal variability of sediment discharges to the bay were also evaluated. Classified images of remotely sensed data revealed the spatial distribution and quantities of land use classes in the region and aided in the discretization of the watershed into homogeneous regions. These regions were modeled using a geomorphic modeling technique based upon spatially averaged parameters.Simulation results from the modeling effort compared favorably with observations at two locations within the watershed. Results showed that runoff and sediment loads from the area exhibit a marked seasonal trend and that deforested areas located in the foothill regions of the watershed contribute a disproportionate share of the sediment load to the bay. In years when rainfall distributions are uniformly distributed over the area, the sediment yields may be up to 100 percent higher than years when the rainfall is concentrated in the heavily forested mountainous regions.
IMPACTS OF AGRICULTURAL DRAINAGE WELL CLOSURE ON CROP PRODUCTION: A WATERSHED CASE STUDY1
Authors: Mohanty B. P. , Tim U. S. , Anderson C. E. , Woestman T. 
Published: June 2007

ABSTRACT: Much of north‐central Iowa is characterized by flat topography, shallow depressions, and poor natural surface drainage. Land drainage systems comprising of tile drains and agricultural drainage wells (ADWs) are used as outlets for subsurface drainage of cropland under corn and soybean production. Studies have shown that these drainage systems, mainly the ADWs, are potential routes for agricultural chemicals to underground aquifers. To protect the region's vital groundwater resource, researchers are evaluating alternative outlets ranging from complete closure of existing ADWs (and creation of wetlands) to continued use of ADWs and chemical management in a comprehensive policy framework.This paper presents the results of a study designed to provide government jurisdictions, farmers, and land managers information for assessing the impact of closing ADWs on crop production. The study couples a geographic information systems database for a 471‐hectare watershed in Humboldt County, Iowa, with a groundwater flow model (MODFLOW) and an empirical crop yield loss model to predict long‐term effects of complete closure of ADWs on crop production. The cropland areas inundated and the relative crop yield loss due to ADW closure are determined as a function of long‐term climatic data. The results indicate that elimination of drainage outlets in the watershed could result in ponding of low‐lying areas and poorly drained soils, making them unsuitable for crop production. Such wetness also decreases the efficiency of production in the no‐ponding areas by isolating fields, and the crop yield loss can be reduced by an annual average of about 18 percent.