bluuebunny/crossref_metadata_2025 huggingface dataset:
POTENTIAL, ACTUAL, AND EQUILIBRIUM EVAPOTRANSPIRATION IN A WHEAT FIELD 1
Authors: MacQuarrie Pamela , Nkemdirim Lawrence C.
Published: June 2007

ABSTRACT: This paper examines the relationship between both potential (E*) and nonpotential evapotranspiration and equilibrium evapotranspiration (EQ) in an irrigated wheat field in southcentral Alberta, Canada. The control exercised by surface wetness and root reservoir moisture content in determining the value of the Priestley‐Taylor constant a is explored. Also investigated is the relationship between a and the vapor flux fraction ET/(R‐G) where ET is the actual evapotranspiration, R the net radiation, and G the soil heat flux. It is shown that evapotranspiration occurred at the potential rate (E*) when the available soil moisture (ASM) within the root zone was ≥3 percent. a varied from 0.84 for a dry soil to 1.49 for a saturated soil. The mean a for E* was 1.24. Surface wetness sustained evapotranspiration at the potential rate when such wetting exceeded 2mm d−1 following a period of prolonged drawdown of soil moisture, α and ET/(R‐G) were positively correlated and this correlation strengthened with increasing soil moisture for constant values of the energy partitioning factor s+γ/s where s is the slope of the saturation humidity‐temperature curve and γ is the psychrometric constant. ET=EQ when ETI(R‐G) lay within the range of 0.59 to 0.82 corresponding to Bowen ratio (β) values of 0.22 and 0.69, respectively.
ASSESSING GROUND WATER POLLUTION POTENTIAL FROM NITROGEN FERTILIZER USING A GEOGRAPHIC INFORMATION SYSTEM1
Authors: Halliday Stuart L. , Wolfe Mary Leigh
Published: June 2007

ABSTRACT: A geographic information system (GRASS 3.1) was used to correlate the availability of nitrogen fertilizer with the susceptibility of ground water to pollution in Texas to identify potential ground water quality problems. An agricultural pollution susceptibility map, produced by the Texas Water Commission using the DRASTIC methodology, was combined with information on cropped areas, recommended nitrogen fertilizer application rates, and aquifer outcrops. A Nitrogen Fertilizer Pollution Potential Index was generated, identifying 24 percent of Texas within the high pollution potential category An analysis of the susceptibility of major aquifer outcrops to potential pollution from nitrogen fertilizer indicated that 34 percent of the outcrop areas fall in the high pollution potential range. It is proposed that correlating the availability of a pollutant with an assessment of the susceptibility of ground water to pollution yields a more accurate screening tool for identifying potential pollution problems than considering susceptibility alone.
EFFECTS OF FOREST FERTILIZATION ON STREAM WATER CHEMISTRY IN THE APPALACHIANS1
Authors: Edwards Pamela J. , Kochenderfer James N. , Seegrist Donald W.
Published: June 2007

ABSTRACT: Stream water chemistry was monitored on two watersheds on the Fernow Experimental Forest in north‐central West Virginia to determine the effects of forest fertilization on annual nutrient exports. Ammonium nitrate and triple superphosphate were applied simultaneously at rates of 336 kg ha−1 N and 224 kg ha−1 P2O5, respectively, which are similar to rates used in commercial forest operations. The treatment significantly increased outputs of several ions. Annual outputs of nitrate N increased as much as 18 times over pretreatment levels, and calcium and magnesium increased as much as three times over pretreatment levels the first year after fertilization. Outputs for these nutrients were elevated for all three post‐treatment years. Although nitrate N increased significantly, only about 20 percent of the applied fertilizer was accounted for in stream water exports. Outputs of phosphate P declined following fertilization, probably because the watersheds are phosphorus deficient, but by the third year, they slightly exceeded predicted values. Estimated nutrient losses to deep seepage were substantial, especially on the leakier south‐facing catchmeat, on which some nutrient losses were equal to or greater than those in stream water. When the nutrient exports associated with both stream discharge and ground water recharge were combined, the percentages of applied N that were lost were similar on the two watersheds, averaging 27.5 percent. Less than 1 percent of the applied P was lost from either watershed in the combination of streamflow and deep seepage.
A PROPOSED METHOD FOR DROUGHT MONITORING1
Authors: Chang Tiao J. , Kleopa Xenia A.
Published: June 2007

ABSTRACT: Existing definitions of drought have focused on limited hydrologic indicators and are less effective for the purpose of drought monitoring. This study uses historical records of streamflow, precipitation, ground water, temperature, and lake elevation to define drought. Based on the method of truncation, drought durations and conditional probabilities of each indicator were estimated to define the drought severity levels, namely, 70 percent, 80 percent, 90 percent, and 95 percent. A drought monitoring method was developed by a combination of truncation level, duration, and conditional probabilities of five indicators. A six‐month period of the 1988 drought in the central Ohio region was used to test the monitoring method. It was found that the developed method could effectively detect an occurrence of drought.
CONCEPTUAL DESIGN PROCEDURE FOR HYDRAULIC DESTRATIFICATION SYSTEMS IN SMALL PONDS, LAKES, OR RESERVOIRS FOR WATER QUALITY IMPROVEMENT1
Authors: Stefan Heinz G. , Gu .Ruochuan
Published: June 2007

ABSTRACT: Forced artificial mixing of temperature‐stratified ponds, or small lakes or reservoirs, by liquid jets can enhance water quality and can also be energy efficient. Based on previous studies of jet mixing mechanics of stratified water bodies, a conceptual design approach is presented. The main “operational” and “system” design parameters are considered in the proposed method. Using minimization of a total cost estimate as a criterion, an iterative method for the selection of the number and size of the jets is developed and illustrated.
EFFECTS OF LOMA PRIETA EARTHQUAKE ON SURFACE WATERS IN WADDELL VALLEY1
Authors: Briggs Robert O.
Published: June 2007

ABSTRACT: Waddell Creek is a perennial stream near Santa Cruz, California, which discharges into the Pacific Ocean about 38 km from the epicenter of the Loma Prieta earthquake (October 17, 1989, M 7.1). The earthquake caused no significant changes or damage to structures or surface features in the area, but was followed by an order of magnitude transient increase in discharge of Waddell Creek and nearby springs. The transients approximate a step rise followed by an exponential recession with time constants of from 37 to 59 days. The flow recession pattern of Waddell Creek was obscured by heavy rains after about 50 days; however, the springs maintained an exponential recession with minimal rain interference for periods of several time constants, then abruptly ceased flowing. A comparison of the pre‐quake and post‐quake chemical signature of one of the springs shows only minor changes in water chemistry indicating a common source for pre‐ and post‐quake waters. Increased permeability of the subsurface ground material appears to be the most probable cause of the hydrologic changes. Post‐seismic reduction of permeability has not been observed or inferred.
MONITORING TRANSIENT WATER QUALITY EVENTS ELECTRONICALLY1
Authors: Whitfield Paul H. , Wade Norman L.
Published: June 2007

ABSTRACT: Electronic instruments are ideally suited to gathering information regarding transient events. Data loggers equipped with water quality sensors offer an opportunity to study events on fine time scales which cannot be sampled using other means. The utility and significance of this type of data gathering is illustrated with data gathered from two small streams. Three examples are used to illustrate some types of transients that can be observed using electronic data acquisition techniques.
TEMPORAL FLUCTUATIONS OF HEAVY RAINFALL MAGNITUDES IN NEW ORLEANS, LOUISIANA: 1871–19911
Authors: Keim Barry D. , Muller Robert A.
Published: June 2007

ABSTRACT: Recent occurrences of heavy rainfall in New Orleans, Louisiana, have led to speculation that the local heavy rainfall regime has changed. To objectively determine the validity of these speculations, changing magnitudes of storm rainfall were investigated through an examination of the annual maximum storm series from 1871 to 1991 at the New Federal site. Although a long‐term trend was not found, the Wilcoxon test indicated that magnitudes during the last 14 years (from 1978–1991) differed significantly from the rest of the series.
PATTERNS OF PERIPHYTON CHLOROPHYLL α IN AN AGRICULTURAL NONPOINT SOURCE IMPACTED STREAM1
Authors: Delong Michael D. , Brusven Merlyn A.
Published: June 2007

ABSTRACT: An agricultural nonpoint source polluted stream in northern Idaho was examined to determine seasonal and longitudinal patterns of periphyton chlorophyll α. Chlorophyll a was measured at eight sites along Lapwai Creek, a fifth order stream impacted by agricultural runoff containing nutrients and eroded soils. Seasonally, periphyton chlorophyll α was lowest in the spring (cumulative x̄= 60.4 mg m−2) and highest in the summer (cumulative x̄= 222 mg m−2). Winter concentrations were higher than expected (cumulative x̄= 168.6 mg m−2). The headwaters, flowing through an open grassy meadow, had the lowest concentrations of the study (two‐year x̄= 49.7 mg m−2). Immediately below a small, eutrophic reservoir, periphyton chlorophyll α increased markedly (two‐year x̄= 155.8 mg m−2) and remained high through a deep canyon (two year x̄= 135.5 mg m−2) and down to the mouth of the stream (two‐year x̄= 172.3 mg−2). Periphyton chlorophyll α in Lapwai Creek was at least two times greater than values reported in the literature for comparable, undisturbed Idaho streams. We suggest that increased nutrient concentrations via agricultural nonpoint source pollution and increased light penetration from the removal of large, woody riparian vegetation have resulted in high periphyton chlorophyll α along the continuum of Lapwai Creek.
VARIATION OF STREAM STABILITY WITH STREAM TYPE AND LWESTOCK BANK DAMAGE IN NORTHERN NEVADA1
Authors: Myers Thomas J. , Swanson Sherman
Published: June 2007

ABSTRACT: Many natural and anthropogenic factors contribute to the stability or erodibility of stream channels. Although a stream rating procedure used by more than 60 percent of the U.S. National Forests provides an estimate of overall stability, it does not identify the cause of instability or indicate corrective management. To better sort natural from livestock influences, stream stability rating indicator variables were related to stream types and levels of ungulate bank damage in a large data base for streams in northern Nevada. Stability and the range in stability varied naturally with stream type. Ungulate bank damage had different effects on different stream types and on different parts of their cross‐sections. Vegetation is more important for stability on certain stream types than on other types. Streams with noncohesive sand and gravel banks are most sensitive to livestock grazing. Range managers should consider the stream type when setting local standards, writing management objectives, or determining riparian grazing strategies.
LOW‐INPUT AGRICULTURE AS A GROUND WATER PROTECTION STRATEGY1
Authors: Diebel Penelope L. , Taylor Daniel B. , Batie Sandra S. , Heatwole Conrad D.
Published: June 2007

ABSTRACT: Protection of ground water quality is of considerable importance to local, state, and federal governments. This study uses a 15‐year mathematical programming model to evaluate the effectiveness of low‐input agriculture, under alternative policy scenarios, as a strategy to protect ground water quality in Richmond County, Virginia. The analysis considers eight policy alternatives: cost‐sharing for green manures, two restrictions on atrazine applications levels, chemical taxation, a restriction on potential chemical and nitrogen levels in ground water only and in surface and ground water, and two types of land retirement programs. The CREAMS and GLEAMS models were used to estimate nitrate and chemical leaching from the crop root zone. The economic model evaluates production practices, policy constraints, and water quality given a long‐term profit maximizing objective. The results indicate that low‐input agriculture alone may not be an effective ground water protection strategy. The policy impacts include partial adoption of low‐input practices, land retirement, and the substitution of chemicals. Only mandatory land retirement policies reduced all chemical and nutrient loadings of ground water; however, they did not promote the use of low‐input agricultural practices.
MULTIPLE OBJECTIVE DECISION MAKING IN WATER RESOURCES1
Authors: Hipel Keith W.
Published: June 2007

ABSTRACT: Recent developments in multiple objective decision making methods presented in the upcoming sequence of research papers are evaluated and compared with respect to their usefulness in addressing challenging problems in water resources management. Because many of the decision making techniques originated in the field of operational research, the historical evolution of this field is outlined and the current need for developing a wide range of techniques for employment in strategic decision making is pointed out. Informative attributes for classifying decision making techniques are given to allow a practitioner to select decision aids that can best model the key characteristics of the particular problems under study. By systematically applying a wide variety of multiple objective decision making techniques to many different kinds of water resources problems, the authors of the papers clearly demonstrate the effectiveness of utilizing these methods for assisting in making both tactical and strategic decisions in water resources management.
MULTICRITERION ANALYSIS OF GROUNDWATER CONTAMINATION MANAGEMENT1
Authors: Shafike Nabil G. , Duckstein Lucien , Maddock Thomas
Published: June 2007

ABSTRACT:Multicriterion decision making (MCDM) techniques were used to analyze a groundwater contamination management problem from the viewpoint of conflicting multiple objectives. The groundwater management model was used to find a compromise strategy for trading off fresh water supply, containment of the waste, and total pumping cost in a hypothetical confined aquifer affected by previous waste disposal action. A groundwater flow model was used to formulate the hydraulic constraints. A linear system model was used to describe drawdown and velocity as functions of the decision variables which were pumping rates. The model determines the pumping location and rates. A modified c‐constraint method was used to generate the set of nondominated solutions which were the alternative compromise strategies. Three different MCDM techniques, Compromise programming (CP), ELECTRA II and MCQA II, were used to select a “satisficing” alternative. Analysis of the results showed that, although these techniques follow different principles, the same preferred strategies were reached. Also, it was noticed that maintaining high groundwater velocities is expensive and difficult. In order to meet a two year target date, large amounts of water had to be pumped. Therefore, rapid restoration results in large pumping volumes and high costs.
GROUND WATER MONITORING NETWORK DESIGN USING MULTIPLE CRITERIA DECISION MAKING ANT) GEOSTATISTICS1
Authors: Woldt W. , Bogardi I.
Published: June 2007

ABSTRACT: A multi‐criteria approach to ground water quality monitoring network design is developed. The methodology combines multi‐criteria decision making (MCDM) and modifications of geostatistical variance reduction analysis. Composite programming, a distance based optimization algorithm that employs a hierarchial structure, is used for the MCDM component of the design methodology. MCDM allows the consideration of numerous, often conflicting, design criteria. The methodology is useful for identifying the preferred combination of direct borehole and indirect geo‐electric data. It also permits the use of prior information during initial stages of network development. Multi‐variate kriging is employed to evaluate network performance using the combination of direct borehole data and indirect geoelectric data. Weighted measures of estimation variance are used as primary measures of performance, with the reduction in estimation variance being computed by the fictitious point method. Case study results demonstrate that the network design methodology can be used in both early and late phases of network development. It also leads to selection of the preferred combination and spatial orientation of direct and indirect data sources while considering cost‐effectiveness and performance of alternative designs.
ANALYSIS OF A KARSTIC AQUIFER MANAGEMENT PROBLEM BY FUZZY COMPOSITE PROGRAMMING1
Authors: Bárdossy András , Duckstein Lucien
Published: June 2007

ABSTRACT: A multiple objective framework for water resources problems possessing uncertain or imprecise elements is provided using distance‐based concepts, fuzzy set theory, and fuzzy arithmetic. The case of regional management of a karstic aquifer in Hungary in which six conflicting objectives and six alternatives have been identified illustrates the methodology The objectives are classified into three groups of two objectives each, namely: (1) environmental (aesthetics, thermal springs temperature), (2) economic (mining, tourism), and (3) water quality (nitrates, phosphates). Both environmental objectives are formulated under fuzziness, and all objectives are scaled using the extension principle. Fuzzy compromise programming (FCP‐I) is then applied; here, all six objectives are entered in a single lp norm measuring the distance between each alternative and an ideal point. Next, fuzzy composite programming (FCP‐II) is developed; here, a trade off is first made within each group of objectives, and then an upper level trade‐off takes place between the three groups. The fuzzy numbers describing each alternative as a result from applying these techniques are ranked to yield an ordering of the alternatives. The results of applying FCP.I, FCP‐II, and two different ordering techniques are compared. The FCP‐II technique appears to provide a relatively simple approach at hierarchical or multilevel multiple objective decision‐making, where uncertainty is described by fuzziness. (KEY TERMS: compromise programming; fuzzy arithmetic; fuzzy sets; hierarchical criteria; karstic aquifer; lp, norms; mining; multiple objectives; thermal springs.)
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.
WATER QUALITY MONITORING NETWORK DESIGN: A PROBLEM OF MULTI‐OBJECTIVE DECISION MAKING1
Authors: Harmancioglu Nilgun B. , Alpaslan Necdet
Published: June 2007

ABSTRACT: Hydrologic data network design is a fairly complicated problem where questions as to the number of gages required, time frequencies to be selected, and benefits/costs of monitoring still remain unresolved. These issues are intensified in case of water quality variables as they are more error‐prone, costly, and time consuming to sample. The basic difficulty underlying the design and evaluation of monitoring systems is the lack of an objective criterion to assess: (a) the efficiency, and (b) cost‐effectiveness of a network. A statistical procedure based on the entropy principle of information theory is proposed to address the evaluation of both factors. Efficiency is measured quantitatively in terms of the information produced by a network. Similarly, benefits of monitoring are described by informative measures for an objective evaluation of cost‐effectiveness. The study presented demonstrates the applicability of the entropy method in assessing the efficiency and the benefits of an existing water quality monitoring network. The method is applied for temporal and spatial features of monitoring, handled as both separate and combined problems. The results are shown in the case of the highly polluted Porsuk River in Turkey. The strengths and shortcomings of the proposed methodology are discussed, with recommendations for future research on the application of the entropy principle in network design.
PERFORMANCE TRADEOFF CHARACTERISTIC OF A FLOOD WARNING SYSTEM1
Authors: Krzysztofowicz Roman
Published: June 2007

ABSTRACT: The performance of a flood warning system can be characterized statistically by three variables: the expected number of detections per year, ND; the expected number of false warnings per year, NP; and the expected lead time of a warning, LT. The Performance Tradeoff Characteristic (PTC) of a warning system is a set of all combinations (ND, NP, and LT) that are feasible to attain in a given system. The concept of PTC is an evolution of the concept of ROC (Relative Operating Characteristic) widely used in detection theory. Each characteristic, ROC and PTC, can be displayed graphically in the form of a family of curves. The displays offer an aid to engineering planning and design of flood warning systems. (KEY TERMS: flood forecasts; flood warnings; reliability; detection; Relative Operating Characteristic; Performance Tradeoff Characteristic.)
A GEOGRAPHICAL ANALYSIS OF WATER‐RELATED CONSTITUTIONAL AMENDMENTS IN TEXAS, 1985–19911
Authors: Schoolmaster F. Andrew.
Published: June 2007

ABSTRACT: Texans participate directly in water policy decision‐making through a referendum process involving amendment of the state's constitution. Prior to 1985, Texans voted on eight amendments. Five of these were ratified (1957, 1962, 1966, 1971, 1976), and collectively resulted in the creation of the Water Development Fund, with an authorization level of $600 million, and the Texas Water Development Board, the organization charged with administering the fund. Three other amendments were defeated in 1969, 1976, and 1981 by ever‐increasing margins. From 1985 to 1991, six additional amendments were proposed and subsequently ratified, resulting in a $1.8 billion increase in Water Development Fund authorization and the creation of an agricultural water conservation fund and bond insurance program. County‐level electoral data for the 1985–1991 referenda were mapped to assess sectional and regional factors underlying public opinion regarding these water resource development and funding programs. Regional contrasts were most pronounced for the 1989 and 1991 referenda that targeted economically distressed areas across the state, particularly the colonias located along the Rio Grande, and the 1989 amendment that removed a time limit on the issuance of agricultural water conservation bonds. As a specific case study, the Texas experience could serve as a guide in California where similar constitutional restrictions require tax and spending programs to be approved by voters, and in other states that may be considering the development of similar state‐level financial programs for water projects.
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.
DISCHARGE CHARACTERISTICS OF PERFORATED PIPE FOR USE IN INFILTRATION TRENCHES1
Authors: Duchene Michael , McBean Edward A.
Published: June 2007

ABSTRACT: Infiltration trenches are an effective stormwater management alternative for the control of urban runoff from small areas. Perforated pipes buried within the gravel of an infiltration trench are used to distribute the inflowing runoff along the length of the trench. Laboratory tests are described that characterize the hydraulics of the orifices in perforated pipes. The results show that the steady‐state exfiltration of water from the pipe into a surrounding gravel trench can be described by the orifice equation.
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.
VENTURA RIVER FLOOD OF FEBRUARY 1992: A LESSON IGNORED?1
Authors: Keller Edward A. , Capelli Mark H.
Published: June 2007

ABSTRACT: On February 12, 1992, a portion of the Ventura River, California, flowed through the Ventura Beach RV Resort which had recently been constructed across a major historically active distributary of the Ventura River delta. State and local land‐use planners recognized the flood hazards associated with the site, but decision‐makers relied on analytical methods developed by the U.S. Army Corps of Engineers and flood‐hazard categories developed by the Federal Emergency Management Agency, which did not adequately reflect the mobile nature of the Ventura River channel and distributaries. A better understanding of the historical behavior of the Ventura River could have averted the flood damages experienced in 1992. Low intensity recreational, agricultural, or habitat restoration use of the site would minimize potential flood damages and obviate the need for structural flood protection that would impact the river's natural resources. Continued operation of the recreational vehicle park could result in additional flood damages in the relatively near future; recognizing the limitations of the flood‐modeling methodologies used for the Ventura Beach RV Resort could prevent similar miscalculations of flood potential in comparable situations.
PERSISTENT CONFLICTS OVER TIMBER PRODUCTION AND WATERSHED MANAGEMENP: A PROBLEM ANALYSIS1
Authors: Abubakar Mohammad M. , Lord William B.
Published: June 2007

ABSTRACT: Most forest lands are managed for multiple purposes, among them timber production and water supply. Conflicts often arise in such cases because logging is perceived as a threat to water quality. These conflicts can result from uncertain factual information, from differences in underlying social values, or from imbalances in the incidence of costs and benefits. Resulting conificts may go unresolved because existing institutional structures fail to address the real roots of the dispute. When such conificts go unresolved, benefits are often lost, and social, political, and managerial costs are high. This study found that the roots of conifict may lie in value differences or in interest impacts, but attention may be focused inappropriately and unproductively on factual issues. It suggests that at least some long‐standing disputes in the management of forested watersheds may be resolved by identifying the root causes of these disputes and choosing those actions, whether they be changes in management guidelines or altered institutional structures, which are appropriate to those causes.
SPATIAL DISTRIBUTION OF POINT SOIL MOISTURE ESTIMATES USING LANDSAT TM DATA AND FUZZY‐C CLASSIFICATION1
Authors: Lindsey Scott D. , Gunderson Robert W. , Riley J. Paul.
Published: June 2007

ABSTRACT: Many hydrologic models have input data requirements that are difficult to satisfy for all but a few well‐instrumented, experimental watersheds. In this study, point soil moisture in a mountain watershed with various types of vegetative cover was modeled using a generalized regression model. Information on sur‐ficial characteristics of the watershed was obtained by applying fuzzy set theory to a database consisting of only satellite and a digital elevation model (DEM). The fuzzy‐c algorithm separated the watershed into distinguishable classes and provided regression coefficients for each ground pixel. The regression model used the coefficients to estimate distributed soil moisture over the entire watershed. A soil moisture accounting model was used to resolve temporal differences between measurements at prototypical measurement sites and validation sites. The results were reasonably accurate for all classes in the watershed. The spatial distribution of soil moisture estimates corresponded accurately with soil moisture measurements at validation sites on the watershed. It was concluded that use of the regression model to distribute soil moisture from a specified number of points can be combined with satellite and DEM information to provide a reasonable estimation of the spatial distribution of soil moisture for a watershed.
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

n 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.
COUPLING OF NONPARAMETRIC FREQUENCY AND L‐MOMENT ANALYSES FOR MIXED DISTRIBUTION IDENTIFICATION1
Authors: Gingras Denis , Adamowski Kaz
Published: June 2007

ABSTRACT:Both L‐moment and nonparametric frequency analyses were performed on a series of annual maximum floods from New Brunswick, Canada. The L‐moment analysis concluded that the data were generated from a unimodal Generalized Extreme Value (GEV) distribution. However, the nonparametric frequency analysis indicated that a majority of stations followed nonunimodal mixed distributions since peak flows occur during different seasons and are the result of different generating mechanisms. The coupling of L‐moment and nonparametric analyses facilitates mixed distribution identification. Thus, the nonparametric method helps in identifying underlying probability distribution, especially when samples arise from mixed distributions.
RECENT RESEARCH ON EFFECTS OF CLIMATE CHANGE ON WATER RESOURCES1
Authors: Chang Lisa H. , Hunsaker Carolyn T. , Draves John D.
Published: June 2007

ABSTRACT: Concentrations of atmospheric CO2 and other radiatively active trace gases have risen since the Industrial Revolution. Such atmospheric modifications can alter the global climate and hydrologic cycle, in turn affecting water resources. The clear physical and biological sensitivities of water resources to climate, the indication that climate change may be occurring, and the substantial social and economic dependencies on water resources have instigated considerable research activity in the area of potential water resource impacts. We discuss how the literature on climate change and water resources responds to three basic research needs: (1) a need for water managers to clearly describe the climatic and hydrologic statistics and characteristics needed to estimate climatic impacts on water resources, (2) a need to estimate the impacts of climate change on water resources, and (3) a need to evaluate standard water management and planning methods to determine if uncertainty regarding fundamental assumptions (e.g., hydrologic stationarity) implies that these methods should be revised. The climatic and hydrologic information needs for water resource managers can be found in a number of sources. A proliferation of impact assessments use a variety of methods for generating climate scenarios, and apply both modeling approaches and historical analyses of past responses to climate fluctuations for revealing resource or system sensitivities to climate changes. Traditional techniques of water resources planning and management have been examined, yielding, for example, suggestions for new methods for incorporating climate information in real‐time water management.
CHANGES TO INFILTRATION AND INTERRILL EROSION FROM LONG‐TERM PRESCRIBED BURNING IN LOUISIANA1
Authors: Dobrowoiski J. P. , Blackburn W. H. , Pearson H. A.
Published: June 2007

ABSTRACT:Effects of long‐term prescribed burning on infiltration and interrill erosion were assessed on two longleaf pine‐bluestem sites in Louisiana. Treatments represented biennially‐applied winter, spring, or summer burning on an upland sandy loam site for 20 years; and annual winter or spring, and biennial winter or spring burns on a bottomland silt loam site for 10 years, with unburned controls. Immediate effects of burning were a reduction in surface cover, exposing soil to raindrop impact. Burning the sandy loam site increased interrill erosion after winter and spring treatments, but produced no immediate changes in infiltration capacity or time to runoff irrespective of treatment season. Rapid recovery of under‐story vegetation mitigated soil exposure. Biennial burning did not increase interrill erosion, or reduce infiltration capacity and time to runoff on the sandy loam site after 20 years. A complete herbaceous understory covered the silt loam site two years after treatment. Interrill erosion was not significantly increased, or infiltration capacity and time to runoff decreased on burning treatments than unburned controls on the silt loam site. Litter biomass was important in predicting interrill erosion. No surface cover condition could be linked to variability in infiltration capacity. This study provides evidence for the resiliency of a longleaf pine‐bluestem association to prescribed burning.
GIS‐ASSISTED REGRESSION ANALYSIS TO IDENTIFY SOURCES OF SELENIUM IN STREAMS1
Authors: See Randolph B. , Naftz David L. , Qualls Charles L.
Published: June 2007

ABSTRACT: Using a geographic information system, a regression model has been developed to identify and to assess potential sources of selenium in the Kendrick Reclamation Project Area, Wyoming. A variety of spatially distributed factors was examined to determine which factors are most likely to affect selenium discharge in tributaries to the North Platte River. Areas of Upper Cretaceous Cody Shale and Quaternary alluvial deposits and irrigated land, length of irrigation canals, and boundaries of hydrologic subbasins of the major tributaries to the North Platte River were digitized and stored in a geographic information system. Selenium concentrations in samples of soil, plant material, ground water, and surface water were determined and evaluated. The location of all sampling sites was digitized and stored in the geographic information system, together with the selenium concentrations in samples. A regression model was developed using stepwise multiple regression of median selenium discharges on the physical and chemical characteristics of hydrologic subbasins. Results indicate that the intensity of irrigation in a hydrologic subbasin, as determined by area of irrigated land and length of irrigation delivery canals, accounts for the largest variation in median selenium discharges among subbasins. Tributaries draining hydrologic subbasins with greater intensity of irrigation result in greater selenium discharges to the North Platte River than do tributaries draining subbasins with lesser intensity of irrigation.
OPTIMIZING THE PROBABILITIES OF WATER YIELD FOR THE RIDAURA AQUIFER (SPAIN)1
Authors: Trilla J. , Estalrich J.
Published: June 2007

ABSTRACT: Aquifer pumping represents, in many geographical locations, an alternative and/or a complementary source of water to surface water supplies. Several Catalonian coastal towns in the northeastern corner of Spain are in this situation. Also, since pumped water is used to supply drinking water, the main purpose in managing these water resources is to supply, no matter the cost, the amount needed at every moment. In other words, the managers of these aquifers attempt to optimize firm water yield. If we think of these aquifers as underground reservoirs with fixed storage capacity, most of the techniques which are applied to surface reservoirs can be implemented. In this paper we use a Stochastic Dynamic Programming model to optimize the yield from the aquifer of the Ridaura River. The objective function in this model was chosen with the aim of maximizing the reliability of the target yields in each of four seasons.
A LUMPED STREAM‐AQUIFER MODEL TO ASSESS RECLAIMED WATER IMPACTS1
Authors: Guymon G. L. , Bagtzoglou A. C. , Welch M. R.
Published: June 2007

ABSTRACT: A lumped, in time and space, model of stream‐aquifer interactions is developed. The model is based upon mass balance and ancillary phenomenological equations that can evaluate changes in streamflow and groundwater quantity and quality. The model is applied to the Santa Margarita River, San Diego County, California to assess the impacts of proposed discharges of reclaimed wastewater on streamflows and underlying groundwaters. The model is relatively simple and economical to apply, thus minimizing analysis costs.
THE VOLUME OF FINE SEDIMENT IN POOLS: AN INDEX OF SEDIMENT SUPPLY IN GRAVEL‐BED STREAMS1
Authors: Lisle Thomas E. , Hilton Sue
Published: June 2007

ABSTRACT: During waning flood flows in gravel‐bed streams, finegrained bedload sediment (sand and fine gravel) is commonly winnowed from zones of high shear stress, such as riffles, and deposited in pools, where it mantles an underlying coarse layer. As sediment load increases, more fine sediment becomes available to fill pools. The volume of fine sediment in pools can be measured by probing with a metal rod, and, when expressed as the fraction (V*) of scoured residual pooi volume (residual pool volume with fine sediment removed), can be used as an index of the supply of mobile sediment in a stream channel. Mean values of V* were as high as 0.5 and correlated with qualitative evaluations of sediment supply in eight tributaries of the Trinity River, northwestern California. Fine‐sediment volume correlated strongly with scoured pool volume in individual channels, but plots of V* versus pool volume and water surface slope revealed secondary variations in fines volume. In sediment‐rich channels, V* correlated positively with scoured pool volume; in sediment‐poor channels, V* correlated negatively with water‐surface slope. Measuring fine sediment in pools can be a practical method to evaluate and monitor the supply of mobile sediment in gravel‐bed streams and to detect and evaluate sediment inputs along a channel network.
SIMULATION OF SEDIMENT AND PLANT NUTRIENT LOSSES BY THE CREAMS WATER QUALITY MODEL1
Authors: Yoon K. S. , Yoo K. H. , Soileau J. M. , Touchton J. T.
Published: June 2007

ABSTRACT: CREAMS was applied to a field‐sized watershed planted to cotton in the Limestone Valley region of northern Alabama. The field was cultivated for three years with conventional tillage (CvT) followed by three years of conservation tillage (CsT). CREAMS is composed of three components: hydrology, erosion, and chemistry. Surface runoff and losses of sediment, N and P were simulated and results were compared with the observed data from the watershed. Curve numbers recommended in the CREAMS user's guide were not adequate for the watershed conditions. The hydrology submodel improved runoff simulation from CvT and CsT when field‐data based curve numbers were used. The erosion submodel demonstrated that CsT reduced sediment loss more than CvT, even though CsT had higher runoff than CvT. The nutrient submodel based on the simulated runoff and sediment underpredicted N loss for both CvT and CsT. This submodel, however, accurately predicted P loss for CvT, but underpredicted for CsT (50 percent lower than the observed). The results of CREAMS simulation generally matched the observed order of magnitude for higher runoff, lower sediment, and higher N and P losses from CsT than from CvT.
MULTICRITERIA EVALUATION IN A POLICY ANALYSIS OF A RHINE ESTUARY1
Authors: Ridgley Mark A. , Rijsberman Frank R.
Published: June 2007

ABSTRACT: As part of a major project to provide the Rhine delta protection from North Sea floods, the Dutch installed sluices at Haringvliet in the late 1960s and converted the Haringvliet‐Hollandsch Diep‐Biesbosch (HHB) estuary into a tidally‐damped, fresh‐water system. Two decades later, the Dutch Rijkswaterstaat commissioned a study of alternative policies for managing the sluices and removing contaminated bottom sediments, including policies which would at least partially restore estuarine conditions to the HHB. This paper describes the public policy analysis comprising that study, focusing on the role played by formal mullicriteria evaluation (MCE), including the Analytic Hierarchy Process. Through the tasks of value‐tree structuring, impact measurement, and criterion prioritization, the MCE influenced the entire structure of the analysis, became an integral part of it, and, despite initial skepticism among the participants about the utility of multicriteria analysis, was subsequently accepted and viewed favorably by the majority of them.