bluuebunny/crossref_metadata_2025 huggingface dataset:
EVALUATION OF MANAGEMENT PRACTICES TO CONTROL AGRICULTURAL POLLUTANTS1
Authors: McTernan William F. , Weand Barron L. , Grizzard Thomas J.
Published: June 2007

ABSTRACT: The objective of this study was to evaluate the effectiveness of various land‐use practices upon the production of nonpoint source pollutants from small agricultural watersheds in Northern Virginia. Pollutant production at each watershed was determined by individual monitoring stations. Data analysis consisted of a determination of the site specific pollutant yield for similar watersheds subjected to differing crop management approaches. These collected data were then compared to those generated by a parametric, event model developed for this investigation. This synthetic data base was used to eliminate or reduce errors resulting from monitoring site differences and to extend the collected data for additional comparisons.
AGRICULTURAL POLLUTION CONTROL: IMPLICATIONS FROM THE RURAL CLEAN WATER PROGRAM1
Authors: Young C. Edwin , Magleby Richard S.
Published: June 2007

ABSTRACT: The Rural Clean Water Program has provided a unique opportunity to study the economics of agricultural nonpoint source pollution control. Several implications for improving the economic efficiency of future agricultural nonpoint source pollution control programs can be drawn from the results. First, individual projects should be targeted towards water bodies that have water quality problems causing economic damages. Considerable variation can exist among areas in the magnitude of economic damages, which may not be proportional to physical impacts. Second, the relative costs and effectiveness of the practices selected to reduce the delivery of pollutants can vary dramatically from one location to another. Early identification and emphasis on cost‐effective BMPs can substantially reduce project costs and may make a project economically justifiable that would not otherwise be so. Finally, some projects that do not hive potential economic benefits from water quality improvements exceeding government cost may have on‐farm benefits from reduced costs and increased long‐term yields that are sufficient to make total benefits (water quality and on‐farm) exceed costs.
“The Optimal Steady‐State in Groundwater Management,” by Keith C. Knapp and Eli Feinerman2
Authors: Reichard Eric C. , Lefkoff L. Jeff
Published: June 2007

Knapp and Feinerman (1985) pose and solve a problem of steady‐state allocation of ground water based directly on the underlying dynamic problem. Their dynamic steady‐state formulation incorporates both the equations of transient ground. water flow and the discount rate. We wish to discuss two aspects of their analysis. First, we question their assertion that the computational advantages of the dynamic steady.state formulation will justify its substitution for the full transient problem. In fact, the dynamic steady‐state problem will often be harder to solve than the properly formulated transient problem. Second, we argue that the dynamic steady‐state is a concept that has limited applicability in ground‐water management. In cases where the optimal steady state is indeed useful, the dynamic solution is often identical to the static solution.
SUSPENDED SEDIMENT AND METALS REMOVAL FROM URBAN RUNOFF BY A SMALL LAKE1
Authors: Striegl Robert G.
Published: June 2007

ABSTRACT: A small lake in the Chicago Metropolitan Area was from 91 to 95 percent efficient in removing suspended sediment and from 76 to 94 percent efficient in removing copper, iron, lead, and zinc from urban runoff. Sediments accumulated in the lake in the form of an organic‐rich mud at an average rate of 20 millimeters per year; this reduced lake storage and covered potential habitat for aquatic organisms. Copper, lead, and zinc concentrations were closely associated with suspended‐sediment concentrations and with silt‐ and clay‐sized fractions of lake sediment. Although concentrations of mercury and cadmium were near detection limits in runoff, measurable concentrations of these metals accumulated in the lake sediments.
CHANNEL DISCHARGE MEASUREMENT BY THERMODILUTION1
Authors: Wittier Rodney J. , Abt Steven R. , Sanders Thomas G.
Published: June 2007

ABSTRACT: An investigation was conducted to determine the feasibility of applying thermodilution technology to discharge measurements in small open channels. A series of tests were performed in which the time‐temperature dilution curves were recorded and analyzed. The independent variables included the channel discharge, the injectate drop height, the volume of tracer, and the mixing distance. Flows ranged from 0.67 cfs to 2.45 cfs with Froude numbers less than 0.30.

The results indicated that the thermodilution technique is a feasible method for discharge measurement. It was determined that a heat content, 1°, of 40°C provides a design criteria in which the mixing distance was related to the flow depth and discharge in a rectangular channel. An empirical expression was derived to determine the approximate mixing distance as a function of the flow depth.
PARAMETER ESTIMATION FOR TPLN DISTRIBUTION FOR FLOOD FREQUENCY ANALYSIS1
Authors: Singh Vijay P. , Singh Kulwant
Published: June 2007

ABSTRACT: The principle of maximum entropy (POME) was used to derive an alternative method for parameter estimation for the three parameter lognormal (TPLN) distribution. Six sets of annual peak discharge data were used to evaluate this method and compare it with the methods of moments and maximum likelihood estimation.
FLOW VARIABLE DISCHARGE PERMITS1
Authors: Noss Richard R. , Gladstone Ileen
Published: June 2007

ABSTRACT: Current approaches to calculating discharge limitations and the use and intent of water quality standards are examined. Flow variable discharge permits, in which the amount of pollutant that may be discharged is based on the magnitude of the flow in the stream, are introduced as an alternative permit strategy that could reduce the cost of pollution control in certain instances while still meeting in‐stream water quality objectives. Several possible designs of flow variable discharge permits are presented to show the flexibility of the concept; for example, permits can be based on instantaneous flows, seasonal flows, trigger values, and ranges of flows.
EFFECTS OF IRRIGATION ON WATER QUALITY OF A SHALLOW UNCONFINED AQUIFER1
Authors: Close M. E.
Published: June 2007

ABSTRACT: The ground water quality of a shallow unconfined aquifer was monitored before and after implementation of a border strip irrigation scheme, by taking monthly samples from an array of 13 shallow wells. Two 30 m deep wells were sampled to obtain vertical concentration profiles. Marked vertical, temporal, and spatial variabilities were recorded. The monthly data were analyzed for step and linear trends using nonparametric tests that were adjusted for the effects of serial correlation. Average nitrate concentrations increased in the preirrigation period and decreased after irrigation began. This was attributed to wetter years in 1978–1979 than in 1976–1977 which increased leaching, and to disturbance of the topsoil during land contouring before irrigation, followed by excessive drainage after irrigation. Few significant trends were recorded for other determinants, possibly because of shorter data records.

Nitrate, sulphate, and potassium concentrations decreased with depth, whereas sodium, calcium, bicarbonate, and chloride concentrations increased. These trends allowed an estimation to be made of the depth of ground water affected by percolating drainage. This depth increased during the irrigation season and after periods of winter recharge. Furthermore, an overall increase in the depth of drainage‐affected ground water occurred with time, which paralleled the development of the irrigation scheme.
EFFECT OF pH ON PHOSPHORUS RELEASE DURING MACROPHYTE (ELEOCHARIS sp.) DECOMPOSITION1
Authors: Ogburn R. Walter. , Brezonik Patrick L. , Delfino Joseph J.
Published: June 2007

ABSTRACT: Laboratory microcosms were used to evaluate the effect of pH on release of soluble reactive phosphorus (SRP) during aerobic decomposition of the aquatic macrophyte Eleocharis sp., which is common in oligotrophic Florida lakes. The total amount of SRP released during a 227‐day incubation in the dark was independent of pH over the range 3.7 to 5.5, but initial rates of release were faster at the lowest pH. The results indicate that the low total phosphorus concentrations observed in many acidic lakes are not necessarily attributable to reduced rates of decomposition and nutrient mineralization at low pH, as some researchers have suggested.
EXAMPLES OF LANDFILL‐GENERATED PLUMES IN LOW‐RELIEF AREAS, SOUTHEAST FLORIDA1
Authors: Russell Gary M. , Stewart Mark , Higer Aaron L.
Published: June 2007

ABSTRACT: Areas of low topographic relief have low water‐table gradients and make the direction of movement of contaminants from land fills in the ground water difficult to predict from regional gradients alone. The landfill, nearby free‐flowing ditches or canals, variations in hydraulic conductivity, and the influence of nearby pumping wells can all affect the direction of flow. In low‐gradient areas the concepts of “upgradient” and “downgradient” are less useful in planning the location of monitoring wells than in areas of higher relief. Low‐relief areas also may be affected by the discharge of mineralized water from deeper aquifers, naturally or through irrigation, which can mask geochemical surveys intended to detect landfill leachate.

Examples of effects of low topographic relief are noted in southeast Florida where water‐table gradients are 7×10−‐4 to 5×10−‐4 feet per foot. Water‐table mounding beneath the landfill and the drainage effects of nearby ditches and well have created multiple leachate plumes in Stuart where one plume migrated in a direction opposite to the apparent regional gradient. In Coral Springs analysis suggests a bifurcating plume migrating along two narrow zones. In Fort Pierce it was difficult to detect leachate because of mineralized irrigation water and fertilizer runoff from an adjacent citrus grove.
INTERSTATE AND INTERNATIONAL COMPETITION FOR WATER RESOURCES1
Authors: Smith Zachary A.
Published: June 2007

ABSTRACT: Federal‐state relations over the management and regulation of ground water resources have undergone a number of changes in recent years. There are a variety of reasons that the role of the federal government in ground water management may increase in the future. One important reason federal policymakers may become involved concerns the extent of competition for ground water resources that cross state and national borders. This article summarizes reasons that interstate and international competition for ground water resources may provide the impetus for federal intervention in ground water management and presents the results of a survey conducted to determine the extent of that competition.
SOIL CONSERVATION PRACTICES AND WATER QUALITY: IS EROSION CONTROL THE ANSWER?1
Authors: Crowder Bradley M. , Young C. Edwin.
Published: June 2007

ABSTRACT: This paper is a computer simulation analysis of an agricultural nonpoint pollution problem. Computer modeling is a universally applicable tool that can be used for establishing the linkages between and the quality of agricultural runoff in both surface and subsurface flow. The tradeoffs between the costs of soil conservation practices and water quality are reported, and the economic implications of such tradeoffs are discussed. Soil and nutrient losses resulting from crop production practices are analyzed using a field‐scale computer simulation model (CREAMS). No‐till planting, reduced tillage, and sod waterway systems are more cost effective than other practices for controlling soil and nutrient runoff losses. Nitrate leaching losses are increased slightly by most soil conservation practices. Terrace systems and permanent vegetative cover impose the greatest societal cost for water quality protection. Public cost sharing and tax incentives encourage farmers to adopt expensive structural practices, and policies are needed to get cost‐effective practices implemented on critical acreage. Extensive treatment of land is necessary for agricultural best management practices (BMPs) to significantly improve water quality in areas that are intensively farmed.
MONITORING AND CONTROL OF CENTER PIVOT SYSTEMS WITH MICROCOMPUTERS1
Authors: Homan Donald M. , Skold Melvin D. , Heermann Dale F.
Published: June 2007

A computerized water‐energy‐management system (WEMS) can be used by center pivot operators to reduce pumping fuel costs and monitoring expenses. Irrigation costs are lowered primarily because the system used climatic data and plant growth models to derive water schedules that considerably lowers the use of water compared with conventional irrigation practices. A capital budget analysis of a hypothetical, but representative farm growing corn, shows that cost savings are from three sources: 61 percent from pumping less water, 28 percent from labor savings, and 11 percent from savings on truck fuel, maintenance, and oiL The analysis illustrates that only a 4 percent water savings from irrigation scheduling over a 10‐year period is required for the investment to be profitable for many central High Plains’ irrigators. The water savings required are relatively small compared with the potentials shown by irrigation scheduling research. WEMS is cost effective and can extend the life of the ground water source.
OPTICAL HETEROGENEITY IN GREEN BAY1
Authors: Effler Steven W. , Auer Martin T.
Published: June 2007

Differences in light penetration and light attenuating components and processes are documented along 112 km of the major (NE/SW) axis of Green Bay (Lake Michigan) during a three‐day cruise (May 25–27, 1982). Measurements included diffuse attenuation of downwelling irradiance (kd), Secchi disk transparency (SD), phytoplankton pigments (chlorophyll a and phaeophytin), turbidity (Tn), and dissolved color (absorbance). The relative importance of absorption and scattering to attenuation was calculated from paired measurements of kd and SD. Absorption and scattering coefficients were calculated; value estimates were supported by a strong linear relationship between the scattering coefficient (b) and Tn (b = 0.99 *Tn; r2= 097, n = 12). Light attenuation characteristics, including the extent of light penetration and the magnitudes and relative importance of absorption, scattering and individual attenuating components, were found to be heterogenous in space. This heterogeneity is due to the characteristics and positions of entry of fluvial discharges to the bay as they influence levels of dissolved color (Gelbstoff), phytoplankton standing crop, and inorganic particulates. Identification of key processes regulating light penetration and their potential for response to pollution control measures can aid in the development of a water quality management plan for Green Bay.
LAKE WATER COLOR: COMPARISON OF DIRECT OBSERVATIONS WITH UNDERWATER SPECTRAL IRRADIANCE1
Authors: Davies‐Colley R. J. , Vant W. N. , Wilcock R. J.
Published: June 2007

ABSTRACT: The water color in 14 lakes of diverse optical character has been computed from near‐surface upwelling irradiance spectra recorded by a submersible spectroradiometer. In these lakes the hues corresponding to irradiance spectra are in reasonable agreement with Munsell hue matches obtained directly by observation in the field. The simple field technique for hue matching using the Munsell standards was broadly validated by this spectroradiometric study. The technique is recommended for further study by limnologists and water resource managers as a potential additional tool for characterizing waters.
GROUND WATER QUALITY PREDICTION USING CLIMATIC INDICES1
Authors: McGregor Kent M. , Marotz Glen A. , Whittemore Donald O.
Published: June 2007

ABSTRACT: Drought affects the quality of ground water in certain aquifers used by municipalities in Kansas. Water quality changes occur as a function of the amount of water available for recharge and hence to dilute more mineralized ground waters. Several measures of meteorological drought, including the Palmer Index and Eagleman Aridity Index, were correlated with water quality data to determine the degree of association. Several locations showed sharp delinces in water quality as the drought progressed. These relationships can be used to predict possible variations in present and future well‐water supplies in locations subject to drought induced water quality deterioration.
NUMERICAL MODELING OF SOLUTE TRANSPORT PATTERNS IN THE DAMMAM AQUIFER1
Authors: Al‐Layla Rashid , Yazicigil Hasan , de Jong Remy
Published: June 2007

ABSTRACT: During the past two decades, the Kingdom of Saudi Arabia has witnessed rapid development in its agricultural and urban areas, which has resulted in greater reliance being placed on its ground water aquifers. The intensive development, particularly along the coastline and in the absence of adequate replenishment sources, has led to major deterioration in the quality and quantity of ground water resources.

A numerical model of the Dammam aquifer in the Eastern Province is developed and used to predict the extent of the saline intrusion in the aquifer. The types of stresses effecting the solute transport were identified and remedial measures were suggested. (KEY TERMS: numerical modeling; Saudi Arabia; aquifer; modeling/statistics.)
EFFECTS OF NO‐FLOW RIVER CONDITIONS ON THE PLATTE RIVER WELL FIELD1
Authors: Nguyen Quang M. , Gilliland Martha W.
Published: June 2007

ABSTRACT: Effects of no‐flow river conditions on the quantity and quality of water in the Platte River well field of the City of Grand Island, Nebraska, were examined utilizing a finite‐difference computer simulation model specifically developed for this well field. Results suggest that the effects of these no‐flow periods on water quality may be most important. In particular, the no‐flow periods eliminate the hydraulic barrier between the well field and an area north of the River that is contaminated with nitrate (concentrations in the 20 to 40 mg/1 NO3‐N range). They also change the direction and velocity of movement of the contaminated ground water. Simulation results indicate that contaminated ground water moves toward the well field with a velocity of 0.42 ft/d after 30 days of no‐flow and 1.43 ft/d after 180 days of no‐flow. Limiting no‐flow conditions to 10 consecutive days would protect the well field.
EFFECTS OF DIVERSIONS ON THE NORTH AMERICAN GREAT LAKES1
Authors: David Martin H. , Joeres Erhard F. , Loucks Eric D. , Potter Kenneth W. , Rosenthal Stuart S.
Published: June 2007

ABSTRACT: Water level fluctuations of the Great Lakes often have created regional controversies among the states and Canadian provinces that share this vast resource. Even though the 100‐year range of their water levels is only four to five feet, episodes of high and low Great Lakes water levels have been a recurring problem throughout the twentieth century. The possibility of increased diversion and consumptive use has exacerbated the existing conflicts over how to manage this water resource. A research project evaluated the effects of interbasin diversion on the Great Lakes system and on the industries that depend on the maintenance of historical water levels, namely hydropower and commercial navigation. The simulation approach employed in this research and some of the important findings are presented. The approach is similar to that used in recent government studies of Great Lakes water level regulation. Several significant modifications were made specifically addressing the diversion issue. Aggregate annual impacts to hydropower and shipping resulting from a diversion of 10,000 cubic feet per second were found to vary from 60 to 100 million dollars. Increases in impacts as a function of diversion rate are nonlinear for the navigation industry.
SOME HYDROLOGIC IMPACTS OF PLOWING RANGELAND SOILS1
Authors: Hutten Neil C. , Gifford Gerald F.
Published: June 2007

ABSTRACT: Rainfall simulator studies were conducted during 1982 and 1983 on agricultural and native rangeland soils of the same soil series in northern Utah. Results indicate that the same soil series mapped at different locations on agricultural land will have similar 10, 20, and 30 minute infiltration rates and similar interrill erosion rates. Seasonal differences in infiltration and erosion rates were significant. Comparisons between agricultural and native soils were complicated by three‐way statistical interactions. Seasonal variations in both infiltration rates and erosion rates were greatest on agricultural soils. Of four soil series on native rangeland, only one showed significant seasonal variation in infiltration rates, while erosion rates were similar across all seasons for all soil series. Soil and cover factors important in predicting infiltration and erosion were identified.
A TAU‐LIKE TEST FOR TREND IN THE PRESENCE OF MULTIPLE CENSORING POINTS1
Authors: Hughes James P. , Millard Steven P.
Published: June 2007

ABSTRACT: A common problem arises in testing for trends in water quality when observations are reported as “less than detection limit.” If a single detection limit is used for the entire study, existing non‐parametric statistical methods, modified for ties, are applicable. If, however, the detection limit varies during the course of the study, resulting in multiple detection limits, then the commonly used trend detection methods are not appropriate. A statistic similar to Kendall's tau, but based on expected ranks, is proposed. Monte Carlo simulations show that the normal approximation to the distribution of this statistic is quite good, even for small samples and a large proportion of censored observations. The statistic is also shown to have greater power than the ad‐hoc method of treating all observations less than the target censored observation as tied.
DRY STREAM REACHES IN CARBONATE TERRANES: SURFACE INDICATORS OF GROUND‐WATER RESERVOIRS1
Authors: Brahana J. V. , Hollyday E. F.
Published: June 2007

ABSTRACT: The method of identifying dry stream reaches in carbonate terrane as surface indicators of potential ground‐water reservoirs offers a valuable exploration technique that is more rapid and less expensive than traditional exploration methods involving random test drilling. In areas where dry stream reaches occur, subsurface drainage successfully competes with surface drainage, and sheet‐like dissolution openings have developed parallel to bedding creating the ground‐water reservoir. The occurrence and hydraulic characteristics of such reservoirs are highly variable, as attested to by the wide range of well yields.

Union Hollow in south‐central Tennessee is the setting for a case study that illustrates the application of the dry stream reach technique. In this technique, dry stream reach identification is based on two types of readily acquired information: (1) remotely sensed black and white infrared aerial photography; and (2) surface reconnaissance of stream channel characteristics. Test drilling in Union Hollow subsequent to identification of the dry reach proved that a localized ground‐water reservoir was present.
TROPICAL EUTROPHIC LAKE MODELING AND PARAMETER DISCRIMINATION1
Authors: Jaffe Peter R.
Published: June 2007

ABSTRACT: Water quality data collected between 1978 and 1981 in a highly lake in Northern Venezuela, Lake Valencia, were analyzed to detect spatial and temporal trends. Based on the results of the analyses, an appropriate nutrient‐algae dynamics model was formulated. Because many parameters, such as the algae concentration were constant over time, and the model is time dependent, the model had to be calibrated with the use of a large and structured trial‐and‐error calibration process. Through the calibration process, the most sensitive parameters of the model were identified, and are in order of importance: the chlorophyll‐to‐nitrogen ratio for algae, the algae settling velocity, the phosphorus release rate from the sediments, the chlorophyll‐to‐phosphorus ratio for algae, and the exchange coefficient in the upper layer of the lake. Model simulations showed that a reduction in the nitrogen load to the lake as well as a reduction in the phosphorus load will decrease the algae population. These model simulations had a high degree of uncertainty associated with them, making additional sampling directed towards the measurement of the sensitive parameters desirable.
FLOW CAPACITY OF CULVERTS ON OREGON COAST RANGE FOREST ROADS1
Authors: Piehl Bradley T. , Pyles Marvin R. , Beschta Robert L.
Published: June 2007

ABSTRACT: One hundred twenty‐eight stream‐crossing culverts in the central Oregon Coast Range were evaluated for peak flow capacity and were compared with current design guidelines. Their ability to pass the 25‐year peak flow, as mandated by Oregon State Forest Practice Rules, and their maximum flow capacity were determined. Over 40 percent of the culverts were unable to pass the 25‐year peak flow at a headwater to diameter ratio of 1. About 17 percent could not pass the 25‐year peak flow without headwater overtopping the roadfill. Installing the next larger pipe size at an additional original installation cost of about 14 percent would have allowed nearly all these culverts to pass the 25‐year peak flow. Culvert capacity varied with ownership and watershed size.
CONFIDENCE INTERVALS FOR FLOOD EVENTS UNDER A PEARSON 3 OR LOG PEARSON 3 DISTRIBUTION1
Authors: Ashkar Fahim , Bobée Bernard
Published: June 2007

ABSTRACT: The Pearson type 3 (P3) and log Pearson type 3 (LP3) distributions are very frequently used in flood frequency analysis. Existing methods for constructing confidence intervals for quantiles (Xp) of these two distributions are very crude. Most of these methods are based on the idea of adjusting confidence intervals for quantiles Yp of the normal distribution to obtain approximate confidence inervals for quantiles Xp of the P3/LP3 distribution. Since there is no theoretical reason why this “base” distribution, Y, should be taken to be normal, we search in the present study for the best possible base distribution for producing confidence intervals for P3/LP3 quantiles. We consider a group of base distributions such as the normal, log normal, Weibull, Gumbel, and exponential. We first assume that the skew coefficient, γ of X, to be known, and develop a method for adjusting confidence intervals for Yp to produce approximate confidence intervals for Xp. We then compare this method (Method A) with another method (Method B) introduced by Stedinger. Simulation shows that the performance of each of these two methods depends on the base distribution Y that is being used, but as a whole, the normal distribution appears to be the best‐fit distribution for producing confidence intervals for P3/LP3 quantiles when γ is assumed to be known. We then extend our method (Method A) to the more important case of unknown coefficient of skewness. It is shown that by taking Y to be Weibull, fairly accurate confidence intervals for P3/LP3 quantiles can be obtained for quite a wide range of sample sizes and coefficients of skewness commonly found in hydrology. The case of the P3 distribution with negative skewness needs further research.
A CATALYST FOR REGIONALIZATION OF RURAL WATER SYSTEMS1
Authors: Miller C. E. , Hamilton L.
Published: June 2007

ABSTRACT: The National Regulatory Research Institute has recommended the merger of small rural water districts in the United States. Success at bringing about merger of these districts, which contain fewer than 3,500 customers, has been highly limited. The subject of this paper is a demonstration project that may act as a catalyst to achieve the desired goal of regionalization. A computerized hydraulic data management program (CHDMP) was developed for a case study in Nelson County, Kentucky. University professors, graduate students, and two water utilities’ staffs cooperated in network analysis employing computer hardware and software. The utilities’ staffs were taught the science and technology of hydraulic model preparation, simulation, and analysis for the case study distribution systems. As an integrated system, the model contained 294 pipes, 234 nodes, six pumps, and 11 tanks. Each utility's problem areas were identified and some of the individual and mutual benefits of hydraulic planning were illustrated. A dialogue resulted between the managers. Each manager described his goals and agreed that, although political merger was not feasible at the present time, future economic factors could be a definite influence in reversing that decision.
GOALS AND DATA COLLECTION DESIGNS FOR WATER QUALITY MONITORING1
Authors: Whitfield Paul H.
Published: June 2007

ABSTRACT: Water quality monitoring cannot address every information need through one data collection procedure. This paper discusses the goals and related procedures for designing water quality monitoring programs. The discussion focuses on the broad information needs of those agencies operating water quality networks. These information needs include the ability to assess trends and environmental impacts, determine compliance with objectives or standards, estimate mass transport, and perform general surveillance. Each of these information needs has different data requirements. This paper outlines these goals and discusses factors to consider in developing a monitoring plan on a site by site basis.
EFFECTS OF SPATIAL ORIENTATION OF MULTIPLE PLATE ARTIFICIAL SUBSTRATES ON INVERTEBRATE COLONIZATION1
Authors: Slack K. V. , Ferreira R. F. , Averert R. C. , Kennelly S. S.
Published: June 2007

ABSTRACT: Jumbo multiple plate samplers were suspended in a river at 0.3 and 1 m depth in one of three orientations: interplate spaces closed to downwelling light and open to flow, open to light and flow, or open to light and closed to flow. Mean numbers of colonizing taxa and individuals were not significantly different among orientations after eight weeks of submergence. All variables tested decreased significantly with depth. Mean number of taxa, number of individuals (1 m only), and insect diversity decreased between samplings at four and eight weeks for samplers that were closed to light and open to flow. All orientations, depths, and durations had one‐half to two‐thirds of the total taxa. Colonization was affected by location in the river and position on sampler suspension equipment. The results indicate lack of orientation effects on colonization or high variability that obscured such effects. The sampler suspension equipment possibly increased among‐sampler variability by forming artificial snag habitats, and interplate light and flow conditions at different orientations may not have been sufficiently distinct to elicit different biological responses. Individual samplers provided diverse microhabitats regardless of orientation, but it would be prudent to include orientation among the variables considered in use of multiple plate samplers.
LOCAL SCOUR AROUND CYLINDRICAL OBJECTS1
Authors: Khanbilvardi R. M. , Akhtar M. W. , Rogowski A. S.
Published: June 2007

ABSTRACT: Several predictors for the maximum local scour around cylindrical objects are compared to available experimental data. The range of flow parameters for which these formulas are valid are presented. The best predictors among those compared in this study were identified. Based on the available data a formula for estimating local scour around cylindrical objects is also given.
HYDROLOGIC MODELING USING A SIMULATION LANGUAGE BASED ON QUEUEING THEORY1
Authors: Arnold J. G. , Williams J. R.
Published: June 2007

ABSTRACT: A novel approach has been developed by applying queueing theory to hydrologic modeling. A queueing situation is characterized by a flow of customers arriving randomly at one or more service facilities. In this case, the customers are represented by water and the service time is the time it takes to move through the soil and over the land. This approach has the potential to be simpler and more efficient than some previously developed models. Another important attribute of queueing theory is its ability to model almost unlimited detail. Many simulation languages based on queueing theory have been developed and tested and are available. Applications of the languages include manufacturing operations, transportation systems, computer systems, financial planning, and health care systems. A model was developed, using a simulation language, to predict runoff hydrographs from storms occurring on small homogeneous watersheds. With continued development, queueing theory could provide an effident, detailed approach to simulating many natural processes.
PREDICTIVE CAPABILITIES OF BATCH‐EXTRACT EXPERIMENTS USING WATER FROM A COAL MINE1
Authors: Naftz David L.
Published: June 2007

ABSTRACT: The ability of batch‐extraction experiments to predict postmining ground water quality was evaluated. As a basis for evaluation, mineralogical and water quality data were used to identify the geochemical reactions that controlled the major‐ion chemistry in batch‐extraction experiments. The experiments used water and spoil material collected from a surface‐coal mine in the Powder River basin of northeast Wyoming. The batch‐extraction experiments consisted of a 2:1 solid:liquid ratio of ground water and spoil material (by weight). The chemical composition of the resulting batch‐extracts was determined after a contact time of 24 hours. Thermodynamically‐favorable reactions included calcite precipitation, gypsum dissolution, and formation of kaolinite as a result of orthoclase feldspar hydrolysis. Three reaction models were consistent with the therinodynanuc and mineralogic data.

In general, the extracts had smaller major‐ion concentrations than did the water samples collected from the spoil aquifer. Correction ratios were calculated from these experiments and could be used in combination with additional batch‐extractions at existing or future lease areas to predict the quality of the ground water after mining.
AN APPLICATION OF INVESTMENT TIMING ANALYSIS: DUAL WATER SYSTEMS1
Authors: Leconte Robert , Narayanan Rangesan , Hughes Trevor C.
Published: June 2007

ABSTRACT: A general methodology to study the economics of dual water systems (defined here as a separate distribution system for untreated low quality local surface Water for outdoor municipal water supply) is summarized and the application of the method to a rapidly growing city is presented. In the first step, a cost‐benefit criterion for evaluating dual systems is developed. The criterion is then extended to a dynamic case where the population to be served increases with time and where the dual system is allowed to expand. The optimal investment time to introduce the dual water supply project is obtained by maximizing social welfare. The model is applied to the city of West Jordan, Utah, where a dual system is currently being proposed. Model results indicate that for the city as a whole dual supply is not economically feasible. However, when the model is applied to a part of the city, it is found feasible and the optimal time to initiate the project would be in the year 1989.
SOIL CHANGES CAUSED BY MUNICIPAL WASTEWATER APPLICATIONS IN EASTERN SOUTH DAKOTA1
Authors: White Everett M. , Dornbush James N.
Published: June 2007

ABSTRACT: Wastewater from a municipal treatment plant was applied in rapid infiltration basins for four years to determine a poorly drained soils effectiveness in removing influent N and P and the soil changes that might limit their removal. About half the total PO4‐P lost from the influent was sorbed in the upper 91 cm of the soil and the other half was sorbed by the soil below the perforated pipe, which was used to drain the basins and collect the effluent for analysis. Drying of the basin soils converted more sorbed PO4‐P to Ca phosphates but the total sorbed was about the same. The in. fluent N decreased, probably by volatilization, because the two basins with surface soil lost soil N rather than gained soil N. The soil total Ca, Mg, and K contents did not change significantly but Na increased slightly. Changes in the physical characteristics of the soils were slight and would have little effect on the longevity of a rapid infiltration basin.
A DESCRIPTIVE STRUCTURE FOR WATER RESOURCE PLANNING1
Authors: Turjoman Abdul‐Mannan , Helweg Otto J.
Published: June 2007

ABSTRACT: Planners should tailor the way they approach a planning study to the particular situation or environment surrounding the study. In order to do this more systematically, this paper suggests a descriptive structure that defines terms and categories of the planning environment. The paper then suggests corresponding terms and categories to define the planning approach as a first approximation. The planner can then tailor the planning approach to the specific study environment. Such an exercise should enhance the success of the planning effort.
APPLICATION OF KRIGING TO ESTIMATING MEAN ANNUAL PRECIPITATION IN A REGION OF OROGRAPHIC INFLUENCE1
Authors: Dingman S. Lawrence. , Seely‐Reynolds Diana M , Reynolds Robert C.
Published: June 2007

ABSTRACT: Estimates of mean annual precipitation (MAP) over areas are the starting point for all computations of water and chemical balances for drainage basins and surface water bodies. Any errors in the estimates of MAP are propagated through the balance computations. These errors can be due to: (1) failures of individual gages to collect the amount of precpitation that actually falls; (2) operator errors; and (3) failure of the raingage network to adequately sample the region of interest. This paper attempts to evaluate the last of these types of error by applying kriging in two different approaches to estimating MAP in New Hampshire and Vermont, USA. The data base is the 1951–1980 normal precipitation at 120 raingages in the two states and in adjacent portions of bordering states and provinces. In the first approach, kriging is applied directly to the MAP values, while in the second, kriging is applied to a “precipitation delivery factor” that represents the MAP with the orographic effect removed. The first approach gives slightly better kriged estimates of MAP at seven validation stations that were not included in the original analysis, but results in an error surface that is highly contorted and in larger maximum errors over most of the region. The second approach had a considerably smoother error surface and, thus, is generally preferable as a basis for point and areal estimates of MAP. MAP estimates in the region have 95 percent confidence intervals of about 20 cm/yr at low and moderate elevations, and up to 35 cm/yr at high elevations. These uncertainties amount to about 20 percent of estimated MAP values.
GOES IR AND DUMMY VARIABLE TECHNIQUES FOR LOW TEMPERATURE ASSESSMENT IN FLORIDA1
Authors: Shih S. F. , Chen E. Y.
Published: June 2007

ABSTRACT: Geostationary Operational Environmental Satellite (GOES) thermal infrared (IR) data were used to study regional cold nocturnal temperature fluctuations that are important in assessing citrus freeze damage. Dummy variables techniques were used to analyze the temperature difference between the east and west sides of Central Florida, which was obtained from both ground measurement minimum temperature (TGMM) and the GOES mean temperature (TGOES) on low‐temperature nights. The low temperature pattern, which was closely related to the citrus freeze damage pattern in Central Florida, was identified by GOES thermal IR data but not by conventional ground measurements. The low surface temperature in the west side and east side appears to be attributable to differences in soil types, water tables, and drainage classes in both regions.
CORRELATION OF COPROSTANOL TO ORGANIC CONTAMINANTS IN COASTAL AND ESTUARINE SEDIMENTS OF THE U.S.1
Authors: Shigenaka Gary , Price James E.
Published: June 2007

ABSTRACT: Results from the National Status and Trends Program, a nationwide effort to evaluate U.S. coastal and estuarine environmental quality, are analyzed to provide information about regional sources of organic contaminants in the benthic environment. Spearman's rank correlation procedure is applied to measurements of coprostanol, a chemical tracer of sewage, and three classes of organic compounds in sediments. The results suggest that discharges from publicly owned treatment works are responsible for concentrations of the organic compounds encountered in the northeastern coastal region, while other sources may predominate in the other regions of the country.
WELFARE IMPLICATIONS OF TUBEWELL IRRIGATION IN BANGLADESH1
Authors: Ahmed Akhter U. , Sampath Rajan K.
Published: June 2007

ABSTRACT: This paper investigates and estimates the welfare loss due to monopoly in tubewell irrigation water market in Bangladesh. In this context, an attempt has been made to evaluate the efficacy of the landless irrigation groups. Using cross‐sectional data and regression analysis, cost and demand functions for irrigation water are estimated. The study demonstrates the relatively superior performance of the landless groups in terms of economic efficiency in shallow tubewell irrigation operation, in comparison to irrigation operation by the landowners.
SHORT‐TERM FORECASTING OF SNOWMELT RUNOFF USING ARMAX MODELS1
Authors: Haltiner J. P. , Salas J. D.
Published: June 2007

ABSTRACT: Time series models of the ARMAX class were investigated for use in forecasting daily riverflow resulting from combined snowmelt/rainfall. The Snowmelt Runoff Model (Martinec‐Rango Model) is shown to have a form similar to the ARMAX model. The advantage of the ARMAX approach is that analytical model identification and parameter estimation techniques are available. In addition, previous forecast errors can be included to improve forecasts and confidence limits can be estimated for the forecasts. Diagnostic checks are available to determine if the model is performing properly. Finally, Kalman filtering can be used to allow the model parameters to vary continuously to reflect changing basin runoff conditions. The above advantages result in improved flow forecasts with fewer model parameters.
WATER POLICIES FOR ENERGY DEVELOPMENT1
Authors: Keith John E. , Narayanan Rangesan
Published: June 2007

ABSTRACF: Examination of a series of studies of the economically efficient water allocations in the Upper Colorado River, Yellowstone River, and Great Basins indicate that water is not a serious general physical constraint on the development of energy resources, so long as public institutions do not hinder the exchange of water rights in markets. Energy development will cause limited impacts on other water‐using sectors, principally agriculture. There appears to be little reason to develop large‐scale water storage facilities, even during periods of reduced water production. Water storage developments appear to be necessary only when institutional constraints severely restrict water rights markets and transfers.
TRENDS IN WESTERN UNITED STATES AGRICULTURE: IRRIGATION ORGANIZATIONS1
Authors: Franklin Douglas R. , Narayanan Rangesan
Published: June 2007

ABSTRACT: From 1940 to 1978, irrigated acreage in the Western United States increased by over 150 percent, irrigated acres per farm increased by 204 percent, and the number of irrigation organizations grew by 31 percent. Understanding the factors affecting these trends (in the structure of irrigated agriculture) is the key to formulating policies for efficient allocation and transfer of water in the west. Four variables that impact the composition of irrigation organizations are farm size changes, organizational efficiency, intersectoral competition for water, and governmental policies. The conclusions show that from 1940 to 1978, the total number of irrigated farms and organizations declined, and the average farm size increased, and larger management oriented organizations such as districts and U.S. Bureau of Reclamation have become more prevalent. With respect to total quantities of water delivered, districts have increased over 50 percent since the 1959 Census and over 100 percent since the 1950 Census, while unincorporated mutuals have declined by approximately 20 percent. Future organizational structure tends to be moving in the direction of more management control as opposed to user control. Changes in water use, delivery, investment, transfers, and laws will continue to change the structure of irrigation organizations and institutions in the west.
THE STRUCTURE AND ROLE OF RIVER AUTHORITIES IN TEXAS1
Authors: Harper Jayson K. , Griffin Ronald C.
Published: June 2007

ABSTRACT: Texas river authorities are a type of large, regional water district that must be financially self‐sufficient. An institutional and historical study of Texas river authorities reveals the broad power of these organizations and their influence in water management. River authorities now control 25 percent of surface water deliveries in Texas. Over two‐thirds of authority water was developed by river authorities; nearly one‐third was purchased from private or public ventures. While river authority activities have been effective where these services are marketable, the provision of public good services is limited. Increased visibility of these organizations is paralleled by challenges to their traditional autonomy.
ESTIMATION OF OPTICAL PROPERTIES OF WATER FROM SECCHI DISK DEPTHS1
Authors: Davies‐Colley R. J. , Vant W. N.
Published: June 2007

ABSTRACT: Optical information on a water body is often required when only Secchi disk depths are available. Many limnologists and water managers have attempted to estimate diffuse light attenuation in water from Secchi depth data assuming a simple inverse relationship. However, we show theoretically that the product of Secchi depth and the diffuse attenuation coefficient is markedly dependent on the reflectance coefficient (“brightness”) of water. Data from 28 New Zealand lakes of diverse optical character demonstrated this dependence over a wide range of reflectance (1.1 to 35.9 percent). Uncritical estimation of attenuation coefficients for diffuse light from Secchi depths, using the currently available simple inverse expressions, is discouraged because of the possibility of bias.
STREAMFLOW CHARACTERISTICS OF SMALL WATERSHEDS IN THE BLUE MOUNTAINS OF OREGON1
Authors: Higgins D. A. , Tiedemann A. R. , Quigley T. M. , Marx D. B.
Published: June 2007

ABSTRACT: Streamflow data for water years 1978–84 were evaluated to identify streamflow characteristics for 13 small watersheds (0.46–7.00 mi2) in the Blue Mountains of eastern Oregon and to determine differences among grazing intensities and vegetation types. The ranges for mean annual water yields, peak flows, and 7‐day low flows for the 13 watersheds were 5.5–28.1 inches, 2.0–34.7 cfsm, and 0.006–0.165 cfsm, respectively. Two classes of vegetation were evaluated: (1) western larch‐Douglas‐fir (nine watersheds) and (2) other (four watersheds representing fir‐spruce, lodgepole pine, ponderosa pine, and mountain meadow). The means for annual peak flows and the slopes of the flow.duration curve were significantly different (p=0.05) for the two vegetation classes; differences in mean annual water yield were marginallysignificant(0.05< p <0.10). After they were adjusted for precipitation, the means for annual water yield, peak flows, and slopes of the flow‐duration curve were significantly different for the two vegetation classes; differences in the means for annual 7‐day low flows were marginally significant. The western larch‐Douglas‐fir group had somewhat lower water yields but, overall, tended to have more favorable streamfiow characteristics including lower peak flows, higher low flows, and more evenly distributed flow regimes (flatter flow‐duration curves) than the “other” class. Four levels of grazing intensity had no effect on streamilow characteristics.