bluuebunny/crossref_metadata_2025 huggingface dataset:
MEASURING THE VALUE OF POTABLE WATER IN PARTIALLY MONETIZED RURAL ECONOMIES1
Authors: Hardner Jared J.
Published: June 2007

ABSTRACT:A pilot study was conducted to test the potential of the Contingent Valuation Methodology (CVM) to reveal the value of non‐market goods in a partially monetized subsistence economy. CVM was used to estimate the willingness to pay, in the form of labor, for potable drinking water in a rural river‐based community located in the Esmeraldas state of northwest Ecuador. Surveys were administered by personal interviews with families living along the waterways of the Santiago river system who used river water for cooking, drinking, washing, and waste disposal.

The mean willingness to pay represented over 23 percent of real income, or 1.4 days per week for a period of one year. Results of multiple regression analysis identified the history of water‐related health problems and the number of working adults in a household as significant determinants of willingness to pay.

Using a non‐monetary, rather than a monetary measure of willingness to pay may provide a more accurate representation of value in a subsistence economy where the use of money is limited. The potential for CVM to measure the benefits of non‐market goods in rural developing regions whose economies are only partially monetized is demonstrated.
CONTROL OF NATURAL BRINE SPRINGS IN BRAZOS RIVER BASIN PART II: BRINE DISPOSAL1
Authors: Spongberg Martin E. , James Wesley P.
Published: June 2007

ABSTRACT: Water quality in the Brazos River of Texas is seriously degraded by natural salt pollution. Two thousand tons/day of total dissolved solids emanate from brine springs and seeps in the Upper Brazos River drainage. Approximately 45 percent of the total salt load comes from a relatively small flow in the Dove Creek area. The companion paper demonstrates that a system of wells pumping brine at a constant rate of about 2 cfs from the near surface aquifer should eliminate the brine springs in this area. In this paper, injection into deep brine aquifers is shown to be a feasible brine disposal alternative. Four brine aquifers were determined from the literature to be possible injection zones. Accurate net aquifer thickness maps were generated in a 23 by 14 mile area centered on the Dove Creek area for three of the aquifers from an interpretation of 41 well logs. Constant injection for a project life of 100 years was simulated using the SWIFT/486 software. Modeling suggests that one well would be sufficient to inject the entire disposal volume into either the Strawn or Ellenburger Formation.
QUANTIFICATION FOR VISUALIZATION OF TIME TREND1
Authors: Snyder W. M. , Thomas A. W. , Dillard A. L. , Mills W. C.
Published: June 2007

ABSTRACT: A method for quantifying fluctuations in time‐series data was developed and tested to aid the process of visualization. The methodology is based on free‐form sliding polynomials and identifies (a) short‐period variability about the mean value, (b) a long‐term trend or cycle, and (c) random errors residual to these two structured components. Consistent results were obtained for designed synthetic data and natural data from seven sites in Georgia. Statistics of fit of the analytical model for the natural data were not significant on a site‐by‐site basis. An unexpected finding for the study was obtained when the statistical results for the seven data sets for temperature were pooled. The smoothing model yielded consistent long‐term trends even though the individual station results were not significant. Also, the correlation coefficients, while low, showed a statistically significant trend toward higher values toward the northwest and away from the Georgia coast line. This study thus supports the concept that multiple‐site, and regionally based, analyses are necessary for the detection of trends. Secondarily, such consistency of results strengthens the conclusion that the proposed smoothing method is an effective procedure in the presence of varying amounts of random content in the natural data sets.
RESIDENCE TIME OF WATER DISCHARGING FROM THE HANGING GARDENS OF ZION PARK1
Authors: Kimball Briant A. , Christensen Paul K.
Published: June 2007

ABSTRACT: The Hanging Gardens are a unique feature of Zion National Park. Knowledge of the source and residence time of water discharging from the Hanging Gardens is necessary to help preserve these features. Ground‐water chemical and isotopic data distinguish the discharge from seeps and springs into two groups, one of low and one of high conductivity. Water with low conductivity likely originates as recharge near the seeps and springs, and it only interacts with the Navajo Sandstone. High conductivity water, on the other hand, originates as recharge on the tops of plateaus to the east, where it interacts with marine rocks of the Carmel Formation. Carbon dating of these ground waters indicates that the low conductivity water is essentially modern recharge, while the high conductivity water was recharged 1,000 to 4,000 years ago.
SPRINGFLOW EFFECTS ON CHEMICAL LOADS IN THE SNAKE RWER, SOUTH‐CENTRAL IDAHO1
Authors: Clark G. M. , Ott D. S.
Published: June 2007

ABSTRACT: The 150‐kilometer middle reach of the Snake River (middle Snake) in south‐central Idaho receives large quantities of water from springs discharging along the north side of the river from the regional Snake River Plain aquifer. Water‐quality samples collected from nine north‐side springs in April 1994 indicated that springs in the upstream part of the reach had larger concentrations of dissolved solids, dissolved nitrate, total nitrogen, tritium, and heavy isotopes of hydrogen and oxygen than to springs in the downstream part of the reach. Because the spring chemistry varies in the reach, discharge from the springs resulted in a degradation in water quality in some parts of the middle Snake and improvements in water quality in other parts. Depending on the annual discharge in the Snake River, the contribution from the north‐side springs represented 33 to 66 percent of the discharge, 32 to 57 percent of the dissolved solids, 26 to 50 percent of the total nitrogen, and 7 to 14 percent of the total phosphorus transported annually from the middle Snake. Synoptic sampling showed that the north‐side springs contributed 84 percent of the discharge and 35, 40, and 10 percent of the dissolved solids, total nitrogen, and total phosphorus load, respectively, to the Snake River during the peak of the irrigation season in 1994.
THE ARMA MODELS APPLIED TO THE FLOW OF KARSTIC SPRINGS1
Authors: Padilla Alberto , Pulido‐Bosch Antonio , Calvache Maria L. , Vallejos Angela
Published: June 2007

ABSTRACT: Autoregressive moving average (ABMA) models have been applied to study the flow series of the karstic springs of La Villa, Fuente Mayor (Spain), and Aliou (France). The theoretical meaning of the parameters involved in the model upon applying it to a simplified scheme of the emptying of a karstic aquifer is first analyzed. The types of transformations necessary to apply these models to the flow series that lack normality and have strong periodic components are also indicated, as are the advantages of this type of model and the physical significance of the parameters obtained, with respect to the standpoint of hydraulics, ranging from rather homogeneous aquifers (La Villa) to extremely karstic (Aliou), including aquifers with intermediate characteristics (Fuente Mayor).
PESTICIDES AND PESTICIDE DEGRADATION PRODUCTS IN STORMWATER RUNOFF: SACRAMENTO RWER BASIN, CALIFORNIA1
Authors: Domagalski Joseph
Published: June 2007

ABSTRACT: Pesticides in stormwater runoff, within the Sacramento River Basin, California, were assessed during a storm that occurred in January 1994. Two organophosphate insecticides (diazinon and methidathion), two carbamate pesticides (molinate and carbofuran), and one triazine herbicide (simazine) were detected. Organophosphate pesticide concentrations increased with the rising stage of the hydrographs; peak concentrations were measured near peak discharge. Diazinon oxon, a toxic degradation product of diazinon, made up approximately 1 to 3 percent of the diazinon load. The Feather River was the principal source of organophosphate pesticides to the Sacramento River during this storm. The concentrations of molinate and carbofuran, pesticides applied to rice fields during May and June, were relatively constant during and after the storm. Their presence in surface water was attributed to the flooding and subsequent drainage, as a management practice to degrade rice stubble prior to the next planting. A photo‐degradation product of molinate, 4‐keto molinate, was in all samples where molinate was detected and made up approximately 50 percent of the total molinate load. Simazine, a herbicide used in orchards and to control weeds along the roadways, was detected in the storm runoff, but it was not possible to differentiate the two sources of that pesticide to the Sacramento River.
SPATIALLY OPTIMIZING FOREST MANAGEMENT SCHEDULES TO MEET STORMFLOW CONSTRAINTS1
Authors: Bevers M. , Hof J. , Troendle C.
Published: June 2007

ABSTRACT: A spatial optimization model is developed and used to limit cumulative effects resulting from storm events by strategically arranging and scheduling forest treatments to meet peak storm‐flow constraints. A mixed integer forest management scheduling formulation is used to select the location and timing of forest treatments. The approach includes simulated spatial routing of storm‐flows imbedded as hydrologic process constraints (in a nested schedule) within longer‐term forest management planning periods in the mathematical programming model. Although difficult to solve, the model shows promise for further research.
EVALUATING POTENTIAL ENVIRONMENTAL IMPACT OF INSECTICIDE APPLICATIONS IN A BOLL WEEVIL ERADICATION PROGRAM1
Authors: Tan X. , Sabbagh G. J. , Cuperus G. W. , Gregory M.
Published: June 2007

ABSTRACT: Concerns have been expressed about the potential insecticide contamination of regional water resources from a boll weevil eradication program in Oklahoma. A mathematical model and geographic information system techniques were utilized to evaluate the potential of insecticide leaching and runoff from a major proposed program area in the state. Different but equally likely weather patterns were generated, and potential insecticide losses associated with each pattern were predicted. Soil types and their locations within cotton areas were identified, and potential chemical losses from each soil were delineated. Model simulations indicated that azinphos‐methyl and diflubenzuron could leach from some porous soils and that all insecticides suggested for use in the program could be lost to runoff. The predicted chemical movements with runoff were significantly higher on irrigated land than from non‐irrigated land. Malathion demonstrated no leaching and low potential of runoff losses among the insecticides evaluated.
WILLOW POSTS BANK STABILIZATION1
Authors: Watson Chester C. , Abt Steven R. , Derrick David
Published: June 2007

ABSTRACT: Harland Creek, in east‐central Mississippi, is a rapidly migrating, meandering stream that is experiencing severe bank erosion. More than 9,000 willow (Salix nigra) posts were emplaced in February 1994 by the U.S. Army, Corps of Engineers in an effort to stabilize eroding stream banks using an experimental bioengi‐neering technique. Monitoring of this stream reach and the willow post bank stabilization has resulted in a data base to assess willow mortality as related to bank aspect, post diameter, cover, and base elevation above low water. Monitoring has also resulted in the development of revised construction guidelines. Survivability of the posts, a necessary condition for long‐term success, was found to average 81 percent in May 1994, 43 percent in October 1994, and 41 percent in August 1995. Even with survivability as low as 29 percent to 34 percent at specific bend reaches, willow posts are documented to be successful in bank stabilization for the period of monitoring, in comparison with more traditional riprap stabilization methods. Guidelines for improved survivability and recommended site selection are presented. Cost of willow post bank stabilization is less than traditional riprap, and willow posts can be emplaced using readily available equipment and materials.
SENSITWITY ANALYSIS OF SIMULATED CONTAMINATED SEDIMENT TRANSPORT1
Authors: Fontaine Thomas A. , Jacomino Vanusa M. F.
Published: June 2007

ABSTRACT: A simulation analysis of contaminated sediment transport involves model selection, data collection, model calibration and verification, and evaluation of uncertainty in the results. Sensitivity analyses provide information to address these issues at several stages of the investigation. A sensitivity analysis of simulated contaminated sediment transport is used to identify the most sensitive output variables and the parameters most responsible for the output variable sensitivity. The output variables included are streamflow and the flux of sediment and Cs137. The sensitivities of these variables are measured at the field and intermediate scales, for flood and normal flow conditions, using the HSPF computer model. A sensitivity index was used to summarize and compare the results of a large number of output variables and parameters. An extensive database was developed to calibrate the model and conduct the sensitivity analysis on a 6.2 mi2 catchment in eastern Tennessee. The fluxes of sediment and Cs137 were more sensitive than streamflow to changes in parameters for both flood and normal flow conditions. The relative significance of specific parameters on output variable sensitivity varied according to the type of flow condition and the location in the catchment. An implications section illustrates how sensitivity analysis results can help with model selection, planning data collection, calibration, and uncertainty analysis.
ESTIMATION OF EPISODIC STREAM ACIDIFICATION BASED ON MONTHLY OR ANNUAL SAMPLING1
Authors: Van Sickle J. , Wigington P J. , Church M. K.
Published: June 2007

ABSTRACT: Programs of monthly or annual stream water sampling will rarely observe the episodic extremes of acidification chemistry that occur during brief, unpredictable runoff events. When viewed in the context of data from several streams, however, baseflow measurements of variables such as acid neutralizing capacity, pH and NO3· are likely to be highly correlated with the episodic extremes of those variables from the same stream and runoff season. We illustrate these correlations for a water chemistry record, nearly two years in length, obtained from intensive sampling of 13 small Northeastern U.S. streams studied during USEPA's Episodic Response Project. For these streams, simple regression models estimate episodic extremes of acid neutralizing capacity, pH, NO3·, Ca2+, SO42−, and total dissolved Al with good relative accuracy from statistics of monthly or annual index samples. Model performances remain generally stable when episodic extremes in the second year of sampling are predicted from first‐year models. Monthly or annual sampling designs, in conjunction with simple empirical models calibrated and maintained through intensive sampling every few years, may estimate episodic extremes of acidification chemistry with economy and reasonable accuracy. Such designs would facilitate sampling a large number of streams, thereby yielding estimates of the prevalence of episodic acidification at regional scales.
SAMPLING AND ANALYTICAL TOLERANCE REQUIREMENTS FOR DETECTING TRENDS IN WATER QUALITY1
Authors: McBride Graham B. , Smith David G.
Published: June 2007

ABSTRACT: In designing a water quality sampling program, the detection threshold (equivalent to “effect size” in a power analysis) can be calculated as a function of the Type I and II error risks, sampling frequency and duration, and (if appropriate) autocorrelation. Then the impact of sampling and analytical errors on the trend that can be detected within that threshold should be considered. A procedure for doing so is described, enabling a priori prescription to laboratory and field staff of the analytical tolerances expected of them in their work. It assumes that the trend (a linear or step change) can be described by a parametric model.
GLOBAL WATER ISSUES AND THE WORLD WATER COUNCIL1
Authors: Abu‐Zeid Mahmoud , Lum Ken
Published: June 2007

ABSTRACT: The key events and the process that led to the creation of the World Water Council on World Water Day 1996 are reviewed and its characteristics summarized. The development of this new organization is discussed in the context of the major global trends in water and water‐related issues, viz. growing water scarcity with its links to limits on food production and demographic patterns. In response to the need to find solutions to these pressing water issues, the development of a Technical Program based on the deliberations of the founding member organizations and a number of short‐term activities have been outlined to demonstrate the evolution of the Council in this first year of its existence. Given the importance of complementarity between the Council and the Global Water Partnership, an attempt has been made to articulate the mutually‐reinforcing roles of the two organizations.
ANALYZING CENSORED WATER QUALITY DATA USING A NON‐PARAMETRIC APPROACH1
Authors: She Nian
Published: June 2007

ABSTRACT:In the analysis of water quality data, samples with concentrations reported below the limit of detection (LOD) are referred to as Type I censored on the left. A variety of procedures have been proposed for estimating descriptive statistics from left‐censored data. Usually, the estimation is carried out by either replacing the LOD with a constant between 0 and the LOD, or assuming the data follow a normal or lognormal distribution. In this paper, a simple transformation is proposed to convert multiple left‐censored water quality data to right‐censored data. The transformed cumulative distribution is similar to a survival function, and enables use of survival analysis techniques for left‐censored data. In particular, the product limit method (Kaplan‐Meier estimator) is applied to estimate descriptive statistics from the transformed data. The performance of the Kaplan‐Meier estimator is compared with maximum likelihood, probability plotting, and substitution methods by Monte Carlo simulations. The Kaplan‐Meier estimator performs as well as or better than these more familiar methods. Finally, the Kaplan‐Meier estimator is used to analyze some priority pollutant data collected in sediment from the central basin of Puget Sound.
NATURAL EROSION RATES AND THEIR PREDICTION IN THE IDAHO BATHOLITH1
Authors: Clayton James L. , Megahan Walter F
Published: June 2007

ABSTRACT:Natural rates of surface erosion on forested granitic soils in central Idaho were measured in 40 m2bordered erosion plots over a period of four years. In addition, we measured a variety of site variables, soil properties, and summer rainstorm intensities in order to relate erosion rates to site attributes. Median winter erosion rates are approximately twice summer period rates, however mean summer rates are nearly twice winter rates because of infrequent high erosion caused by summer rainstorms. Regression equation models and regression tree models were constructed to explore relationships between erosion and factors that control erosion rates. Ground cover is the single factor that has the greatest influence on erosion rates during both summer and winter periods. Rainstorm intensity (erosivity index) strongly influences summer erosion rates, even on soils with high ground cover percentages. Few summer storms were of sufficient duration and intensity to cause rilling on the plots, and the data set was too small to elucidate differences in rill vs. interrill erosion. The regression tree models are relatively less biased than the regression equations developed, and explained 70 and 84 percent of the variability in summer and winter erosion rates, respectively.
DETECTING CILANGES IN THE SPATIAL DISTRIBUTION OF NITRATE CONTAMINATION IN GROUND WATER1
Authors: Liu Zhi‐Jun , Hallberg George R. , Zimmerman Dale L. , Libra Robert D.
Published: June 2007

ABSTRACT: Many studies of ground water pollution in general and nitrate contamination in particular have often relied on a one‐time investigation, tracking of individual wells, or aggregate summaries. Studies of changes in spatial distribution of contaminants over time are lacking. This paper presents a method to compare spatial distributions for possible changes over time. The large‐scale spatial distribution at a given time can be considered as a surface over the area (a trend surface). The changes in spatial distribution from period to period can be revealed by the differences in the shape and/or height of surfaces. If such a surface is described by a polynomial function, changes in surfaces can be detected by testing statistically for differences in their corresponding polynomial functions. This method was applied to nitrate concentration in a population of wells in an agricultural drainage basin in Iowa, sampled in three different years. For the period of 1981–1992, the large‐scale spatial distribution of nitrate concentration did not show significant change in the shape of spatial surfaces; while the magnitude of nitrate concentration in the basin, or height of the computed surfaces showed significant fluctuations. The change in magnitude of nitrate concentration is closely related to climatic variations, especially in precipitation. The lack of change in the shape of spatial surfaces means that either the influence of land use/nitrogen management was overshadowed by climatic influence, or the changes in land use/management occurred in a random fashion.
STRUCTURAL EQUATION MODELING OF DYNAMICS OF NITRATE CONTAMINATION IN GROUND WATER1
Authors: Liu Zhi‐Jun , Hallberg George R. , Malanson George P.
Published: June 2007

ABSTRACT: Most research on the temporal aspect of nitrate pollution in water resources has focused on surface water. Comprehensive studies on the dynamics of nitrate in ground water are lacking, especially on a drainage basin scale and for relatively long periods of time. In this study, structural equation modeling is applied in investigating the influences of climate, hydrology, and nitrogen management in agricultural production on nitrate concentration in the Big Spring Basin, Iowa, over a 10‐year period. The study shows that for given hydrogeological settings, nitrogen management practices and climate are the two most important factors that affect nitrate dynamics. The long‐term trend of nitrate is closely related to the nitrogen input primarily determined by management practices. The potential effects of nitrogen management, however, are contingent on the variations of climate. The improvements in water quality (reduced nitrate concentration and loads) in relation to improved nitrogen management are often overshadowed by the impact of climate, especially in extremely dry or wet years. The variations of climate and hydrology have much greater impacts on the nitrate dynamics than the changes in nitrogen input. This study reveals significant seasonal variation in the relations between nitrate concentration and influencing factors, which is also closely related to the seasonal variation in climate. Assessment of management practices and resultant water quality should consider the impact of short‐ and long‐term climate dynamics.
URBANIZATION, FLOOD FREQUENCY, AND SALMON ABUNDANCE IN PUGET LOWLAND STREAMS1
Authors: Moscrip Amy L. , Montgomery David R.
Published: June 2007

ABSTRACT: Urbanization history and flood frequencies were determined in six low‐order streams in the Puget Lowlands, Washington, for the period between the 1940150s and the 1980190s. Using discharge records from USGS gauging stations, each basin was separated into periods prior to and after urban expansion. Four of the study basins exhibited significant changes in urbanized area, whereas two of the study basins exhibited only limited change in urbanized area and effectively serve as control basins. Each of the basins that experienced a significant increase in urbanized area exhibited increased flood frequency; pre‐urbanization 10‐year recurrence interval discharges correspond to 1 to 4‐year recurrence interval events in post‐urbanization records. In contrast, no discernible shift in flood frequency was observed in either of the control basins. Spawner survey data available for three of the study basins reveal systematic declines in salmon abundance in two urbanizing basins and no evidence for decreases in a control basin. These data imply a link between ongoing salmon population declines and either increased flood frequency or associated changes in habitat structure.
THE FLOOD OF '96 AND ITS SOCIOECONOMIC IMPACTS IN THE SUSQUEHANNA RWER BASIN1
Authors: Yarnal B. , Johnson D. L. , Frakes B. J. , Bowles G. I. , Pascale P.
Published: June 2007

ABSTRACT: The meteorology flood hydroclimatolog and socioeconomic impacts of the Flood of January 1996 in the Susquehanna River Basin are explored. The analysis explains how an unusual storm system brought high humidities, high temperatures, strong winds, and heavy rain to the basin. The rapid melt of the deep snowpack, combined with the heavy rainfall, produced the sudden release of large volumes of water. Because the ground surface was frozen or saturated, this water moved primarily as overland flow. Thus, the flood waters were not restricted to areas immediately adjacent to stream channels and, consequently, some of the largest impacts were on people, property, and infrastructure in areas not normally prone to flooding. Socioeconomic patterns of flooding over time and space are investigated to put this flood into context and to highlight its impacts. The analysis concludes that if such overland flooding is a more common feature of climate change, then the current vulnerability to this form of flooding and its economic implications must be considered carefully.
MATCHING NATURAL WATER COLORS TO MUNSELL STANDARDS1
Authors: Davies‐Colley Robert J. , Smith David G. , Speed David J. , Nagels John W.
Published: June 2007

ABSTRACT: Color of natural waters strongly influences their aesthetic appeal, suitability for recreational use, and aquatic habitat, but methods for routine specification of color have been lacking. An improved method has been developed for specifying water colors in the field. The water color, seen through an underwater viewer, is matched directly to Munsell standard patches observed simultaneously. The Munsell color‐matching method was verified versus measurements of the underwater light field, made with a submersible spectroradiometer in 20 different natural waters in New Zealand (mainly lakes), which varied widely in color and other optical characteristics. Hue, the most important color attribute of natural waters, could be matched accurately; the saturation and brightness less so. Color standard patches are not available covering the full range of typically dark water colors, but fortunately, brightness can be measured with simple submersible light sensors. The Munsell color matching method seems suitable for routine water resources survey and monitoring.
CHALLENGES IN GROUND WATER REMEDIATION: DENSE NONAQUEOUS PHASE LIQUIDS1
Authors: Dierolf Charlotte
Published: June 2007

ABSTRACT: Dense nonaqueous phase liquid (DNAPL) contaminated ground water has proven to be exceptionally difficult to remediate for both physical and chemical reasons. Since DNAPL's are denser than water, their movement is not governed by the direction of ground water flow as is generally the case for other ground water contaminants. Additionally, DNAPLs' interactions with aquifer solids through processes such as sorption tend to make the pollution linger or sometimes apparently disappear, only to return later. Unfortunately, pump‐and‐treat systems, the traditional way ground water contamination is addressed, have not been effective in cleaning DNAPL contaminated water. Other remediation technologies continue to be developed to address these problems. Policy changes will also be necessary to effectively address the difficulties associated with ground water remediation.
THE POTENTIAL FOR REMOTE SENSING OF LOESS SOILS SUSPENDED IN SURFACE WATERS1
Authors: Lodhi Mahtab A. , Rundquist Donald C. , Han Luoheng , Kuzila Mark S.
Published: June 2007

ABSTRACT: The potential for detecting the concentration and type of soils suspended in surface water through remote sensing techniques was investigated by studying the spectral reflectance of two types of soils in suspension. In a large tank filled with 7510 liters of water, 20 levels of suspended sediment (soil) concentration (SSC), ranging from 50 to 1000 mg/l were prepared. A high resolution spectroradiometer was used to measure the reflectance at each SSC level. The reflectance spectra of two contrasting soils were distinct in the visible and near infrared (NIR) portions of the electromagnetic spectrum. The wavelength range between 580–690 nm (visible) was found to be optimal for indicating the type of soil, whereas, the wavelength range between 714–880 (NIR) was found to be appropriate for estimating the concentration of sediment suspended in surface waters.
QUALITY OF HYDROMETEOROLOGICAL DATA IN COLD REGIONS1
Authors: Peck Eugene L.
Published: June 2007

ABSTRACT: Many users of hydrometeorological records are not aware of the number of inconsistencies and biases that occur in hydrometeorological records. Examples are presented illustrating how the exposures of sites for measurement of precipitation, wind, snow on the ground, and evaporation determine to a large extent how useful the records are for estimating areal conditions. For areas where precipitation in the form of snow produces a significant portion of the runoff, a smaller number of quality records may be more valuable for modeling than a much larger number of records of lower quality. Information is presented to show that the overall value of an operational hydrometeorological network is dependent upon how consistent and representative of average conditions the collected records are, especially for mountainous areas in cold regions.
URBAN STORMWATER QUANTITY/QUALITY MODELING USING THE SCS METHOD AND EMPIRICAL EQUATIONS1
Authors: Tsihrintzis Vassilios A. , Hamid Rizwan
Published: June 2007

ABSTRACT: Runoff depth and pollutant loading (Biological Oxygen Demand [BOD5], Total Suspended Solids [TSS], Total Kjeldahl Nitrogen [TKN] and lead [Pb]) computations of urban stormwater runoff from four small sites (i.e., 14.7–58.3 ac) in South Florida were performed using the Soil Conservation Service (SCS) hydrology method and empirical equations developed by the U.S. Environmental Protection Agency (EPA). Each site had different predominant land uses (i.e., low density residential, high density residential, highway and commercial). Quantity and quality data from 95 storm events at these sites were measured by the U.S. Geological Survey (USGS), and used for calibration of the methodology to derive appropriate input parameters. Calibrated input parameters were developed for each land use to test the applicability of the methodology in small sub‐tropical urban watersheds, and to provide hydrologists with a way to select appropriate parameter values for planning studies. A total of 16 independent rainfall events were used for verification of the methodology. Comparisons of predicted versus measured data for both hydrographs and pollutant loadings were performed.
NUTRIENT CONCENTRATIONS IN WASTEWATER TREATMENT PLANT EFFLUENTS, SOUTH PLATTE RWER BASIN1
Authors: Pocernich Matthew , Litke David W.
Published: June 2007

ABSTRACT: Accurate data about nutrient concentrations in wastewater treatment plant effluents are needed for river basin water‐quality studies. As part of the U.S. Geological Survey's National Water‐Quality Assessment Program in the South Platte River Basin, nutrient data were requested from 31 wastewater‐treatment plants located in the basin. This article describes the types of nutrient data available from the plants, examines the variability of effluent nutrient concentrations, and discusses methods for estimation of nutrient concentrations where data are lacking.

Ammonia was monitored at 88 percent of the plants, nitrite plus nitrate was monitored at 40 percent of the plants, and organic nitrogen and phosphorus were monitored at less than 25 percent of the plants. Median total nitrogen concentrations and median total phosphorus concentrations were small compared to typical literature estimates for wastewater‐treatment plants with secondary treatment. Nutrient concentrations in effluent from wastewater‐treatment plants varied widely between and within plants. For example, ammonia concentrations varied as much as 5 mg/L during a day, as much as 10 mg/L from day to day, and as much as 30 mg/L from summer to winter within a plant. In the South Platte River Basin, estimates of median annual ammonia and nitrite plus nitrate concentrations can be improved based on plant processes; and nitrite plus nitrate and organic nitrogen concentrations can be estimated based on ammonia concentrations. However, to avoid large estimation errors, more complete nutrient data from wastewater‐treatment plants are needed for integration into river basin water quality studies. The paucity of data hinders attempts to evaluate the relative importance of point source and nonpoint source nutrient loadings to rivers.
CRITIQUE OF WASHINGTON'S WATERSHED ANALYSIS PROGRAM1
Authors: Collins Brian D. , Pess George R.
Published: June 2007

ABSTRACT: We evaluate Washington's program of watershed analysis with respect to its goals as a cumulative effects assessment method, adaptive management, and a restoration tool. We also evaluate the program as a framework for implementing ecosystem management. A strength of the cumulative effects assessment method is in identifying and reducing the dominant, direct physical effects of forest land uses on salmonid habitat. This could be further strengthened by more emphasis on identifying problems that can be immediately remedied (e.g., identifying road erosion and landslide trigger sites; correctly locating fish‐bearing waters, and identifying anthropogenic fish passage impediments). More effectively assessing and integrating changes from more than one type of input to streams, including all relevant inputs, and examining whether assumptions about those inputs are scientifically defensible, will also improve the cumulative effects assessment. Treating experimentation more formally, including placing a greater emphasis on monitoring the outcome of prescriptions, and determining the scientific defensibility and certainty level of prescriptions, will strengthen adaptive management. As a watershed restoration tool, the program needs defined goals and critical assessment methods (e.g., of historic productive capacity of aquatic habitat). To be consistent with ecosystem management, analyses need to be integrated into a larger spatial scale, and to include all relevant land uses and effects within that scale; objectives for various stream ‘inputs” need to be evaluated with respect to managing for ecological integrity and the ability to provide a measurable standard.
SPATIAL AND TEMPORAL WATER QUALITY VARIABILITY IN THE PIRACICABA RIVER BASIN, BRAZIL1
Authors: Krusche A. V. , de Garvaiho F. P. , de Moraes J. M. , de Camargo P. B. , Ballester M. V. R. , Hornink S. , Martinelli L. A. , Victoria R. L.
Published: June 2007

ABSTRACT: The spatial and temporal variability of dissolved oxygen (DO), biochemical oxygen demand (BOD), nitrate concentration and total coliform (TC) were investigated at nine sampling stations distributed along the main rivers of the Piracicaba River Basin, a 12,400 km2 catchment located in São Paulo State, one of the most developed regions of Brazil. Spatially, a downstream impoverishment of water quality conditions was observed, as seen by the decrease of DO, and increase of BOD, nitrate, and TC. These changes were probably caused by accumulating downstream discharge of domestic and industrial sewage. Temporal evaluation of 18 years of data showed that DO decreased with time for the majority of the sampling stations, while BOD, nitrate, and TC increased. A law, approved at the end of 1991, proposed a new water tax for river water extraction for industrial and agricultural use. The amount of this tax is determined according to the water quality of the extracted water. Therefore, the evaluation of the water quality status in this basin is a first step to help resources managers to determine the values for this tax.
EFFECTS OF BEST MANAGEMENT PRACTICES ON FOREST STREAMWATER QUALITY IN EASTERN KENTUCKY1
Authors: Arthur M. A. , Coltharp G. B. , Brown D. L.
Published: June 2007

ABSTRACT:Forest land managers are concerned about the effects of logging on soil erosion, streamflow, and water quality and are promoting the use of Best Management Practices (BMPs) to control impacts. To compare the effects of BMP implementation on streamwater quality, two of three small watersheds in Kentucky were harvested in 1983 and 1984, one with BMPs, the other without BMPs. There was no effect of clearcutting on stream temperatures. Streamflow increased by 17.8 cm (123 percent) on the BMP watershed during the first 17 months after cutting and by 20.6 cm (138 percent) on the Non‐BMP watershed. Water yields remained significantly elevated compared to the uncut watershed 8 years after harvesting. Suspended sediment flux was 14 and 30 times higher on the BMP and Non‐BMP Watersheds, respectively, than on the uncut watershed during treatment, and 4 and 6.5 times higher in the 17 months after treatment was complete. Clearcutting resulted in increased concentrations of nitrate, and other nutrients compared to the uncut watershed, and concentrations were highest on the non‐BMP watershed. Recovery of biotic control over nutrient losses occurred within three years of clearcutting. The streamside buffer strip was effective in reducing the impact of clearcutting on water yield and sediment flux.
GROUND WATER MANAGEMENT OPTIMIZATION USING GENETIC ALGORITHMS AND SIMULATED ANNEALING: FORMULATION AND COMPARISON1
Authors: Wang M. , Zheng C.
Published: June 2007

ABSTRACT: Genetic algorithms (GA) and simulated annealing (SA), two global search techniques, are coupled with MODFLOW, a commonly used groundwater flow simulation code, for optimal management of ground water resources under general conditions. The coupled simulation‐optimization models allow for multiple management periods in which optimal pumping rates vary with time to reflect the changing flow conditions. The objective functions of the management models are of a very general nature, incorporating multiple cost terms such as the drilling cost, the installation cost, and the pumping cost. The models are first applied to two‐dimensional maximum yield and minimum cost water supply problems with a single management period, and then to a multiple management period problem. The strengths and limitations of the GA and SA based models are evaluated by comparing the results with those obtained using linear programming, nonlinear programming, and differential dynamic programming. For the three example problems examined in this study, the GA and SA based models yield nearly identical or better solutions than the various programming methods. While SA tends to outperform GA in terms of the number of forward simulations needed, it uses more empirical control parameters which have significant impact on solution efficiency but are difficult to determine.
SPATIAL VARIABILITY OF CONDUCTWITY AS APPLIED TO DISTRIBUTED PARAMETER INFILTRATION MODELS1
Authors: Shin Daehyok , Lee Kang‐Kun , Kim Jung‐Wk
Published: June 2007

ABSTRACT: Two infiltration models, called VVSIM (variable variance stochastic infiltration model) and EVVSIM (enhanced variable variance stochastic infiltration model), are developed in this study. A distributed parameter infiltration model can estimate the amount of infiltration over a field area by computing the infiltration over zones of the field area. Hydraulic conductivity is the most important parameter determining infiltration in simulations by infiltration models. The performance of an infiltration model depends on how well the model accommodates the complicated spatial distribution of hydraulic conductivity. The two proposed models include the effects of spatial correlation of the conductivity distribution. Virtual conductivity fields are generated using the turning bands method. Monte Carlo simulations show that the proposed models give infiltration estimates more accurate than those obtained by the other models employed.
ESTIMATING THE MEAN AND VARIANCE OF CENSORED PHOSPHORUS CONCENTRATIONS IN FLORIDA RAINFALL1
Authors: Ahn Hosung
Published: June 2007

ABSTRACT: The total phosphorous (TP) concentrations in the South Florida rainfall have been recorded in weekly intervals with a detection limit (DL) of 3.5 μg/L. As a large amount of the data is reported as below the DL, appropriate statistical methods are needed for data analysis. Thus, an attempt was made to identify an appropriate method to estimate the mean and variance of the data. In particular, a method to separate the statistics for the below DL portion from the estimated population statistics is proposed. The estimated statistics of the censored data are compared with the statistics of the uncensored data available from the recent years’ laboratory records. It was found that the one‐step restricted maximum likelihood method is the most accurate for the wet TP data, and that the proposed method to combine the estimated statistics for TP < DL portion and the sample statistics for TP ≥ DL portion improves estimates compared to the conventional maximum likelihood estimates.
A COMPARATIVE STUDY OF LINEAR AND NONLINEAR TIME SERIES MODELS FOR WATER QUALITY1
Authors: Jian Xiaodong , Yu Yun‐Sheng
Published: June 2007

ABSTRACT:Surface water quality data are routinely collected in river basins by state or federal agencies. The observed quality of river water generally reflects the overall quality of the ecosystem of the river basin. Advanced statistical methods are often needed to extract valuable information from the vast amount of data for developing management strategies. Among the measured water quality constituents, total phosphorus is most often the limiting nutrient in freshwater aquatic systems. Relatively low concentrations of phosphorus in surface waters may create eutrophication problems. Phosphorus is a non‐conservative constituent. Its time series generally exhibits nonlinear behavior. Linear models are shown to be inadequate. This paper presents a nonlinear state‐dependent model for the phosphorous data collected at DeSoto, Kansas. The nonlinear model gives significant reductions in error variance and forecasting error as compared to the best linear autoregressive model identified.
RESEARCH ISSUES IN FOREST HYDROLOGY1
Authors: Black Peter E.
Published: June 2007

ABSTRACT: This paper explores a range of forest hydrology issues and identifies my concepts of the field's most pressing research needs. I extend the topic to include teaching and education in the broader sense because current teaching is usually part of the researcher's portfolio and because education involves that of both the research scientist and a broader audience. I consider the primary research, education, and service roles of the forest hydrologist also within a range of domains or, as I prefer to identify them, scales: (1) the molecular or pore level; (2) hydrological process; (3) watershed function; (4) global considerations, and (5) the human dimension which, while not actually a scale itself, embraces, is important to, and is affected by the first four. All are topics screaming for attention by researchers, educators, and practitioners. I shall here focus on the middle three.
FOREST HYDROLOGY ISSUES FOR THE 21ST CENTURY: A CONSULTANT'S VIEWPOINT1
Authors: Swanson Robert H.
Published: June 2007

ABSTRACT: Forest hydrology should be a mature science with routine use of hydrological procedures to evaluate the effect of past, current and proposed harvesting practices on water resources. It is not. However, water users are pressuring forest managers to exercise their role in managing forested watersheds for water supply. Most forest managers are poorly equipped to carry out this role. Forestry schools need to ensure that their graduates, whether employed in forest management positions or as specialists in watershed management, understand that all forestry operations may affect instream or downstream water users. Specialists in forest hydrology should be fully aware of the following: (1) climate and watershed characteristics influence streamflow in separate ways; (2) forestry practices produce changes in water yield and quality, and that only these changes need to be evaluated to estimate their effects; (3) watershed storage is a critical factor in evaluating the effects of harvesting on streamflow; and (4) the effect of harvest on one watershed cannot be extrapolated to another without consideration of the processes affected. Research is needed to assist watershed managers in applying models to watersheds for which climate and streamflow data are insufficient. Research is also needed to incorporate climate, streamflow and other data for hydrological models into geographic information systems. Joint research projects are needed to develop physical relationships between stream channel characteristics of importance to fisheries biologists and streamflow characteristics affected by forest harvest.
ECONOMIC EVALUATION OF RIPARIAN BUFFERS IN AN AGRICULTURAL WATERSHED1
Authors: Qiu Zeyuan , Prato Tony
Published: June 2007

ABSTRACT: This study determines the most cost effective spatial pattern of farming systems for improving water quality and evaluates the economic value of riparian buffers in reducing agricultural nonpoint source pollution in a Midwestern agricultural watershed. Economic and water quality impacts of alternative farming systems are evaluated using the CARE and SWAT models, respectively. The water quality benefits of riparian buffers are estimated by combining experimental data and simulated water quality impacts of fanning systems obtained using SWAT. The net economic value of riparian buffers in improving water quality is estimated by total watershed net return with riparian buffers minus total watershed net return without riparian buffers minus the opportunity cost of riparian buffers. Exclusive of maintenance cost, the net economic value of riparian buffers in reducing atrazine concentration from 45 to 24 ppb is $612,117 and the savings in government cost is $631,710. Results strongly support efforts that encourage farmers to develop or maintain riparian buffers adjacent to streams.