bluuebunny/crossref_metadata_2025 huggingface dataset:
PHYTOPLANKTON PRODUCTIVITY AND BIOMASS IN THE CHARLOTTE HARBOR ESTUARINE SYSTEM, FLORIDA1
Authors: McPherson Benjamin F. , Montgomery Ralph T , Emmons Edward E.
Published: June 2007

ABSTRACT: Phytoplankton carbon‐14 productivity at a depth of 50 percent of surface light and chlorophyll‐α concentrations were measured every other month from November 1985 through September 1986 at 12 stations in the Charlotte Harbor estuarine system. Maximum productivity and chlorophyll‐α concentrations occurred during summer or early autumn near the mouths of tidal rivers. Most of the variability in light‐normalized productivity and chlorophyll‐α could be attributed to two factors derived from Principal Component Analysis of ambient water‐quality characteristics. One factor related to seasonal variability and the other to spatial variability. The seasonal factor incorporated the interaction of temperature and nutrients. The spatial factor incorporated the interaction of salinity, nutrients, and water color that resulted from the mixing of freshwater inflow and seawater. Although freshwater inflow increased the availability of nutrients in low salinity (less than 10‰) waters, the highly colored freshwater restricted light penetration and phytoplankton productivity. Maximum productivity and biomass occurred where color associated with the freshwater inflow had been diluted by seawater so that light and nutrients were both available. Concentrations of inorganic nitrogen were often at or below detection limit throughout most of the high salinity (greater than 20‰) waters of the estuary and was probably the most critical nutrient in limiting phytoplankton productivity.
APPLICATION OF A SEDIMENT ROUTING MODEL TO A MIDDLE EUROPEAN WATERSHED1
Authors: Hrissanthou V
Published: June 2007

ABSTRACT: A simulation model that computes sediment yield due to sheet and rill erosion at the outlet of a large watershed requires daily precipitation and the soil, topographic, and vegetative characteristics of the watershed. An important problem, particularly in a large watershed, is the transport of sediment produced in the sub‐watersheds to the outlet of the whole watershed. This problem is approached mathematically by a sediment routing model that is used as a component of the total model.
UNIT HYDROGRAPHS FOR DEVELOPING DESIGN FLOOD HYDROGRAPHS1
Authors: Singh Krishan P.
Published: June 2007

ABSTRACT: In Illinois, a procedure has been developed to derive unit hydrographs for generating 100‐year and probable maximum flood hydrographs, on the basis of 11 parameters that define the hydrograph shape very well. Regional regressions of these parameters with basin factors show very high correlation. Thus satisfactory values of parameters can be determined for ungaged areas or those with a few years' record. The nonlinearity in unit hydrographs derived from usual floods is largely attributed to mixing within‐channel and overbank‐flow flood events. To minimize the effects of nonlinearity and to derive unit hydrographa suitable for calculating spillway design floods, use of the proposed method of developing such hydrographs is recommended.
MODELING STUDIES FOR PLANNING: THE GREEN BAY PROJECT1
Authors: Martin James L. , Richardson William L. , McCutcheon Steven C.
Published: June 2007

ABSTRACT: A major contaminant monitoring and modeling study is underway for Green Bay, Lake Michigan. Monitoring programs in support of contaminant modeling of large waterbodies, such as for Green Bay, are expensive and their extent is often limited by budget limitations, laboratory capacity, and logistic constraints. Therefore, it is imperative that available resources be used in the most efficient manner possible. This use, or allocation of resources, may be aided through the application of readily available models in the planning stages of projects.

To aid in the planning effort for the Green Bay project, a workshop was held and studies designed to aid in the allocation of resources for a year‐long intensive field study. Physical/chemical and food chain models were applied using historical data to aid in project planning by identifying processes having the greatest impact on the predictive capability of mass balance models. Studies were also conducted to estimate errors in computed tributary loadings and in‐Bay concentrations and contaminant mass associated with different sampling strategies. The studies contributed to the overall project design, which was a collaborative effort with many participants involved in budgeting, field data collection, analysis, processing of data, quality assurance, data management and modeling activities.
PROBLEM OF NONPOINT SOURCE AGRICULTURAL WATER POLLUTION: TOWARD A HYPOTHETICAL FEDERAL LEGISLATIVE SOLUTION1
Authors: Caulfield Henry P.
Published: June 2007

ABSTRACT: A conceptual framework of politics is set forth in relation to the federal environmental legislative process. This framework for analysis is then related to a hypothetical public problem ‐ground water pollution from agricultural chemicals. The public problem from the perspective of political analysis is found to involve several different types of difficult issues with which the legislative process must deal if legislation is to be enacted.
MULTIVARIATE TREND TESTING OF LAKE WATER QUALITY1
Authors: Loftis Jim C. , Taylor Charles H. , Newell Avis D. , Chapman Phillip L.
Published: June 2007

ABSTRACT: Multivariate methods of trend analysis offer the potential for higher power in detecting gradual water quality changes as compared to multiple applications of univariate tests. Simulation experiments were used to investigate the power advantages of multivariate methods for both linear model and Mann‐Kendall based approaches. The experiments focused on quarterly observations of three water quality variables with no serial correlation and with several different intervariable correlation structures. The multivariate methods were generally more powerful than the univariate methods, offering the greatest advantage in situations where water quality variables were positively correlated with trends in opposing directions. For illustration, both the univariate and multivariate versions of the Mann‐Kendall based tests were applied to case study data from several lakes in Maine and New York which have been sampled as part of EPA's long term monitoring study of acid precipitation effects.
MAGNETIC TRIGGER FOR AUTOMATIC PUMPING SAMPLERS1
Authors: Kress Michael W. , Turton Donald J.
Published: June 2007

ABSTRACT: A stage‐activated triggering device was developed for automatic pumping samplers. The device consists of a proximity switch and ten magnets mounted radially at equal intervals on a plexiglass disk. The triggering device allows discrete sampling of stream water at 3.0 cm intervals of stage. The trigger proved dependable during two years of use at three headwater streams in the Ouachita Mountains of southeastern Oklahoma.
REGULATING NONPOINT SOURCE POLLUTION IN SURFACE WATERS: A PROPOSAL1
Authors: Foran Jeffery A. , Butler Peter , Cleckner Lisa B. , Bulkley Jonathan W.
Published: June 2007

ABSTRACT: Nonpoint sources (NPS) are an important and continuing source of toxic and conventional pollutants to surface waters. The Clean Water Act amendments of 1987 call for the regulation of these sources through the use of Best Management Practices (BMP). However, BMP implementation has generally occurred on a voluntary basis. This paper proposes a regulatory mechanism to control nonpoint source pollution. The regulatory mechanism involves the development of consortia, made up of all parties potentially responsible for NPS pollution, the development of wasteload allocations that coordinate the pollutant contributions from both point and nonpoint sources in a stream segment, and the issuance of permits to consortia to regulate the impacts of NPS pollution and ensure achievement of state or federal Water Quality Criteria and Standards.
THE RESTON (VIRGINIA) LAKE‐USE SURVEY: PUBLIC PERCEPTIONS AND MANAGEMENT IMPLICATIONS1
Authors: Butler Larry T , Redfield Garth W.
Published: June 2007

ABSTRACT: A public attitude survey was developed by a citizen committee and mailed to all residences (14,747) in the planned, suburban community of Reston, Virginia, which is responsible for maintaining four small, recreational impoundments. Over 18 percent of survey forms were returned, and characteristics of the survey sample suggest that the suite of respondents was representative of the Reston community as a whole. Of those respondents indicating a preferred lake use, 48 percent chose walking or looking as most important; boating as second at 27 percent; and fishing was third, favored by only 8 percent. Citizens feel strongly (94 percent) that the lakes are valuable community assets. Appearance was the characteristic most valued by 62 percent of respondents, and 58 percent considered degradation of water quality either the first or second most important ecological issue affecting local lakes. These findings provide a decisive public mandate for lake management activities related to visual quality. In response to this survey, the Reston Association, a homeowners' organization responsible for the lakes, increased public access of visual enjoyment, intensified litter control, expanded activities in public education on lake management and ecology, and continued a long‐term program of water quality monitoring.
AQUATIC HABITAT CONDITION INDEX, STREAM TYPE, AND LWESTOCK BANK DAMAGE IN NORTHERN NEVADA1
Authors: Myers Thomas J. , Swanson Sherman
Published: June 2007

ABSTRACT: The quality of stream habitat varies for a variety of natural and anthropogenic reasons not identified by a condition index. However, many people use condition indices to indicate management needs or even direction. To better sort natural from livestock influences, stream types and levels of ungulate bank damage were regulated to estimates of aquatic habitat condition index and stream width parameters in a large existing stream inventory data base. Pool/riffle ratio, pool structure, stream bottom materials, soil stability, and vegetation type varied significantly with stream type. Pool/riffle ratio, soil and vegetation stability varied significantly with ungulate bank damage level. Soil and vegetation stability were highly cross‐correlated. Riparian area width did not vary significantly with either stream type or ungulate bank damage. Variation among stream types indicates that riparian management and monitoring should be stream type and reach specific.
ESTIMATING CENTRAL TENDENCY FROM UNCENSORED TRACE LEVEL MEASUREMENTS1
Authors: Porter P. Steven , Ward Robert C.
Published: June 2007

ABSTRACT: The statistical analysis of data which have trace level measurements has traditionally been a two‐step process in which data are first censored using criteria based on measurement precision, and then analyzed with statistical methods for censored data. The process might be more informative if data were left uncensored. In this paper, information loss attributable to censoring and measurement noise are assessed by comparing the sample mean and median of uncensored measurements with a log regression mean and median based on censored data. Measurements are derived from lognormal parent distributions which have random variability characteristic of trace level measurement. The relative performance of estimators used with error‐free samples and with samples having measurement noise can be explained by differences between the probability distributions of parents and measurements. Measurement introduces bias and dispersion and transforms lognormal parent distributions toward greater symmetry. Estimates using uncensored data are less biased and more accurate than the log regression mean and median when censoring exceeds about 50 percent, and are not much worse at any fraction censored. For data with many (80 percent) results below the limit of detection, bias may be quite severe.
HYDROCLIMATIC VARIABILITY IN THE ROCKY MOUNTAINS1
Authors: Changnon David , McKee Thomas B. , Doesken Nolan J.
Published: June 2007

ABSTRACT: The spatial and temporal variability of hydroclimatic elements were investigated in the central and northern Rocky Mountains (Colorado, Idaho, Montana, Utah, and Wyoming) during the 1951–1985 period. The three hydroclimatic elements studied were total water‐year (October 1‐September 30) streamflow (ST), winter (October 1‐March 31) accumulated precipitation (PR), and April 1 snowpack (SN). An analysis of 14 virgin watersheds showed wide spatial djfferences in the temporal variability of SN, PR, and ST, and these were found to be caused largely by basin exposure to moist air flows. The more stable (low variability) basins were those exposed to prevailing northerly to westerly flow, while unstable (high variability) basins were exposed to occasional southwesterly to southeasterly moist flow. Snowpack was the better indicator of ST in 11 of the 14 watersheds, explaining 37 to 87 percent of the ST variance.

Analysis of the spatial variability, based on all SN and PR data from across the study area, revealed 11 discrete climatic regions. Both SN and PR exhibited coherent regions of stable and unstable temporal variability. The average variability between stable and unstable regions differed by a factor of two, and the differences were best explained by the exposure of the mountain barrier to moist air flows.
EFFECTS OF ADVANCED WASTEWATER TREATMENT ON THE QUALITY OF WHITE RIVER, INDIANA1
Authors: Crawford Charles G. , Wangsness David J.
Published: June 2007

ABSTRACT: In 1983, the City of Indianapolis, Indiana, completed construction of advanced wastewater treatment (AWT) systems to enlarge and upgrade its existing Belmont Road and South port Road secondary treatment plants. A nonparametric statistical procedure, a modified form of the Wilcoxon‐Mann‐Whitney rank‐sum test, was used to test for trends in water quality at two upstream and two downstream sites on White River and at the two treatment plants. Results comparing the pre‐ (1978–1980) and post‐ (1983–1986) AWT periods show statistically significant improvements in the quality of the treated effluent and of the White River downstream from the plants. Water quality at sites upstream from the city was relatively constant during the period of study. Total ammonia (as N) decreased 14.6 mg/L and BOD5 (five‐day biochemical oxygen demand) decreased 10 to 19 mg/L in the two effluents. Total ammonia in the river downstream from the plants decreased 0.8 to 1.9 mg/L and BOD5 decreased 2.3 to 2.5 mg/L. Nitrate (as N) increased 14.5 mg/L in the plant effluents and 2.0 to 2.4 mg/L in the river because of in‐plant nitrification. Dissolved oxygen concentration in the river increased about 3 mg/L because of reduced oxygen demand for nitrification and biochemical oxidation processes.
ESTIMATING EROSION RISKS ASSOCIATED WITH LOGGING AND FOREST ROADS IN NORTHWESTERN CALIFORNIA1
Authors: Rice Raymond M. , Lewis Jack
Published: June 2007

ABSTRACT:Erosion resulting from logging and road building has long been a concern to forest managers and the general public. An objective methodology was developed to estimate erosion risk on forest roads and in harvest areas on private land in northwestern California. It was based on 260 plots sampled from the area harvested under 415 Timber Harvest Plans completed between November 1978 and October 1979. Results confirmed previous findings that most erosion related to forest management occurs on a small fraction of the managed area. Erosion features larger than the minimum size inventories in this study (> 13 yd3) occupied only 0.2 percent of the area investigated. Linear discriminant analysis was used to develop two equations for identifying critical sites (sites with erosion >100 yd3ac−1). The equations were based on slope, horizontal curvature (an expression of local topography), and soil color (on road sites) or the strength of the underlying rocks (on harvest sites). The equations can be used in planning to estimate the erosion risk of proposed activities. They can also be used to estimate acceptable risk thresholds based on the value of competing resources.
USING GROUND WATER BASINS AS STORAGE FACILITIES IN SOUTHERN CALIFORNIA1
Authors: Matthews Christine A.
Published: June 2007

ABSTRACT: Southern California, now in its fifth consecutive year of drought, has always relied heavily on imported water from the Owens Valley, the State Water Project, and the Colorado River. For various reasons, these sources are now decreasing and water suppliers are being forced to look for new sources. One possible alternative is to store water obtained during peak supply periods for use during dry periods in ground water storage basins. The Santa Ana River Basin in Orange County has already been developed, and is being used to provide water to 25 cities in Orange County. The San Juan Basin, also in Orange County, is being studied as a possible future storage basin. This paper examines some of the positive and negative aspects of developing and using ground water storage basins in Southern California.
ANTIDEGRADATION WATER QUALITY CRITERIA FOR THE DELAWARE RIVER: A DISTRIBUTION‐FREE STATISTICAL APPROACH1
Authors: Jay Breidt F , Boes Duane C. , Wagner Joel I. , Flora Mark D.
Published: June 2007

ABSTRACT: Existing water quality for the Middle Delaware Scenic and Recreational River is significantly better than is required by current standards, leaving a potential for degradation. A method is presented for deriving candidate antidegradation water quality criteria for this segment of the Delaware River using statistical analysis of historic (ambient) water quality data. Data for 34 water quality parameters are first evaluated for data density, serial correlation, trend, seasonality, and other factors. These preliminary analyses are based on observation of data plots and application of distribution‐free statistical techniques that are insensitive to outliers and are robust to relatively mild violations of basic assumptions. Data for 12 of the parameters have sufficient density for further analysis and can reasonably be modeled as independent and identically distributed over time (either seasonally or for the entire data sets). For these 12 parameters, distribution‐free statistical methods are developed and used to derive intervals within which there is high confidence (usually greater than 95 percent) that the quantiles with potential use as anti‐degradation criteria (the 0.85th, 0.90th, and 0.95th quantiles in this study) for a particular parameter lie.
DROUGHT PLANNING: A PROCESS FOR STATE GOVERNMENT1
Authors: Wilhite Dorald A.
Published: June 2007

ABSTRACT: Drought has been a prevalent feature of the American landscape during the latter part of the 1980s, producing serious socioeconomic and environmental consequences. These recent experiences with drought have renewed concern about the inadequacy of federal and state contingency planning efforts and the lack of coordination for assessment and response efforts between these levels of government. This paper presents the results of research aimed at facilitating the preparation of drought contingency plans by state government in conjunction with a state's overall water management planning activity. The ten‐step drought plan development process reported is intended to improve mitigation efforts through more timely, effective, and efficient assessment and response activities. Officials in appropriate state agencies should examine the proposed framework and alter it to best address drought‐related concerns, adding or deleting elements as necessary.
THE PRACTICE OF COMBINED SEWER SYSTEM MODELING1
Authors: Nix Stephan J. , Moffa Peter E. , Davis Daniel P.
Published: June 2007

ABSTRACT: A combined sewer system is a complex system subject to the dynamic stimuli of precipitation, runoff pollution loads, and sanitary wastes. The system response is a random series of pollutant loads to a receiving water. In many localities, these discharges create considerable water quality problems. Mathematical models can and have played a useful role in predicting the behavior of combined sewer systems and evaluating abatement strategies.

Based on the authors' experiences over the past several years, this paper explores some of the positive and negative aspects of using deterministic mathematical models to simulate the behavior of combined sewer systems. A case study follows a discussion on modeling objectives, limitations of modeling, model selection, establishing model credibility, and many other considerations necessary in modeling and simulating these systems.
LONG‐TERM CHANGES IN STREAMFLOW FOLLOWING LOGGING IN WESTERN OREGON AND ASSOCIATED FISHERIES IMPLICATIONS1
Authors: Hicks Brendan J. , Beschta Robert L. , Harr R. Dennis.
Published: June 2007

ABSTRACT: The long‐term effect of logging on low summer streamflow was investigated with a data set of 36 years. Hydrologic records were analyzed for the period 1953 and 1988 from Watershed (WS) 1 (clear‐cut logged and burned), WS 2 (unlogged control), and WS 3 (25 percent patch‐cut logged and burned) in the H. J. Andrews Experimental Forest, western Cascade Range, Oregon. These records spanned 9–10 years before logging, and 21–25 years after logging and burning. Streamfiows in August were the lowest of any month, and were unaffected by occasional heavy rain that occurred at the beginning of summer. August streamfiows increased in WS 1 compared to WS 2 by 159 percent following logging in WS 1, but this increase lasted for only eight years following the start of logging in 1962. Water yield in August for 1970–1988 observed from WS 1 was 25 percent less than predicted from the control (WS 2, ANOVA, p=0.032).

Water yield in August increased by 59 percent after 25 percent of the area of WS 3 was patch‐cut logged and burned in 1963. In contrast to WS 1, however, water yields from WS 3 in August were consistently greater than predicted for 16 years following the start of logging, through to 1978. For the 10 years, 1979–1988, water yield observed in August from WS 3 was not different than predicted from the control (WS 2, ANOVA, p‐0.175).

The contrasting responses of WS 1 and 3 to logging are thought to be the result of differences in riparian vegetation caused by different geomorphic conditions. A relatively wide valley floor in WS 1 allowed the development of hardwoods in the riparian zone following logging, but the narrow valley of WS 3 and limited sediment deposits prevented establishment of riparian hardwoods.

Low streamflows during summer have implications for salmonid survival. Reduced streamflow reduces the amount of rearing habitat, thus increasing competition. Combined with high water temperatures, reduced streamflow can lead directly to salmonid mortality by driving salmonids from riffles and glides, and trapping them in drying pools. Low streamflow also increases oxygen depletion caused by leaves from riparian red alders.
CHANNELIZATION EFFECTS ON OBION RIVER FLOODING, WESTERN TENNESSEE1
Authors: Shankman David , Samson Scott A.
Published: June 2007

ABSTRACT: Much of the Obion River in western Tennessee was channelized into the 1960s. Stage data from three stream‐flow gaging stations on the Obion were used to determine how channelization affected flood frequency and annual maximum stage. Channelization affected the upper and lower Obion River differently. Flooding has become infrequent on the upper Obion River since channelization, even during the winter and spring which is the wettest time of year. In contrast, except for the winter months, there has been little effect on flood frequency on the lower Obion River where stage is highly dependent on the Mississippi River. The Mississippi River often backs up and floods the Obion River more than 50 km above its mouth and may contribute to flooding at an even greater distance upstream by reducing the water‐surface gradient and slowing discharge. Channelization on the upper section of the river and many of the small tributaries has increased flow efficiency, but has also caused channel erosion and downstream deposition, reducing the cross‐sectional channel area and possibly contributing to downstream flooding. Maximum annual stages at the upper and lower Obion River changed little. Therefore, the maximum surface area, submerged at least once each year, has been unaffected by channelization.
HYDROLOGIC EFFECTS OF TWO METHODS OF HARVESTING MATURE SOUTHERN PINE1
Authors: Ursic S. J.
Published: June 2007

ABSTRACT: Hydrologic responses to logging with skidders and responses to logging with a cable yarder are compared. After a 23‐year calibration with an undisturbed control catchment, mixed stands of shortleaf pine (Pinus echinata Mill.) and hardwoods were clearfelled on two small catchments in the hilly Coastal Plain of north Mississippi and observed for five years. Runoff increased 370 mm (skidded) and 116 mm (yarded) during the first year with 1876 mm of rainfall, and 234 mm (skidded) and 228 mm (yarded) during the second year when 1388 mm of precipitation equaled the calibration mean. Sediment concentrations for the yarded catchment during the first two years averaged 641 and 1,629 mg L−1, respectively, and yields were 6,502 and 12,086 kg ha−1. Compared to calibration means of 74 mg L−1 and 142 kg ha−1, these extreme values can be attributed largely to transport of sediment stored in the channel and to erosion of subsurface flow paths, which was exacerbated by high flow volumes. During the first year, the concentration (231 mg L−1) and yield (2,827 kg ha−1) for the control catchment also exceeded the calibration means. However, concentrations (134 mg L−1) and yields (1,806 kg ha−1) for the skidded catchment were about 40 percent lower than for the control catchment during the first year, and were higher than those for the control only during the second year. Because deep percolation was limited and because rainfall was unusually high, increases in flows and sediment concentrations and yields probably approximate maximum responses to clearcut harvesting in the uplands of the southern Coastal Plain.
BEST MANAGEMENT PRACTICES FOR STORM WATER AND INFILTRATION CONTROL1
Authors: Whipple William
Published: June 2007

ABSTRACT: Water quality controls of storm water runoff and infiltration should be a major part of a nonpoint source control program. Although surface runoff and ground water controls are often approached separately, coordination between the two is essential. For practical reasons, a rather simplified technology‐based approach appears to be desirable. Areas affected vary greatly as to their sensitivity to pollution; and the various classes of pollutant source vary greatly as to their potential harmfulness. In effect, a matrix approach appears best, in which both vulnerability of the area and harmfulness of the pollutant source would have weight in determining which level of best management practices (BMP) would be appropriate, whether standard, special, or complete prohibition of the type facility under given circumstances.
DOCUMENTED AUTUMNAL STREAMFLOW INCREASE WITHOUT MEASURABLE PRECIPITATION1
Authors: Doyle P. F.
Published: June 2007

ABSTRACT: In the south‐central interior of British Columbia, the summer and fall of 1987 were very dry. Streamflow was extremely low throughout the region, and an extended rainless period coincided with the onset of the winter dormant period. During a five‐day rainless period from October 9 to October 13, which should have been a period of declining streamflow in all watersheds, 19 of 31 small forested watersheds having suitable natural flow record experienced increasing discharge. The data is reviewed and analyzed with an initial attempt made to explain the streamflow changes among the various watersheds quantitatively. The only explanation for the widespread increases in streamflow in the region during this dry period is that greatly reduced transpiration, as the vegetation went dormant, permitted increased volumes of water in the soil to drain into surface streams rapidly enough to be recorded as increased discharge in 61 percent of the study streams.
USING SOIL TEXTURE TO ESTIMATE SATURATED HYDRAULIC CONDUCTIVITY AND THE IMPACT ON RAINFALL‐RUNOFF SIMULATIONS1
Authors: Loague Keith
Published: June 2007

ABSTRACT: In this paper a new set of soil texture data is used to estimate the spatial distribution of saturated hydraulic conductivity values for a small rangeland catchment. The estimates of conductivity are used to re‐excite and re‐evaluate a quasi‐physically based rainfall‐runoff model. The performance of the model is significantly reduced with conductivity estimates gleaned from soil texture data rather than the infiltration data used in our previous efforts.
ESTIMATING REFERENCE EVAPORATION IN THE CENTRAL VALLEY OF CALIFORNIA USING THE LINACRE MODEL1
Authors: Hope Allen S. , Evans Shelly M.
Published: June 2007

ABSTRACT: The Linacre (1988) model for calculating evaporation from open water or well‐watered surfaces only requires inputs of air temperature, latitude and elevation, and windspeed if it is available. The model was developed using data collected at a large number of sites in different climatic regions of the world, while independent tests of the model have shown it to be suitable for estimating evaporation in a variety of locations. This study was intended to contribute to the broad goal of evaluating temperature‐based evaporation models for use in California by testing the Linacre model in the agriculturally intensive Central Valley. Observed monthly mean reference evaporation (Eo) and meteorological data for periods ranging up to 72 months were obtained from 25 California Irrigation and Management Information System (CIMIS) stations distributed throughout the Central Valley. Uncalibrated and calibrated Linacre models were used to estimate monthly mean reference evaporation, and the performance of each model was evaluated using indices that quantified the random and systematic errors and overall model performance. The accuracy of the radiation and ventilation components of the model were evaluated separately. The uncalibrated model was found to systematically overestimate Eo with most of the model error being attributed to the ventilation component. Calibration of the radiation and ventilation components removed most of the systematic model errors, and the root mean square error for monthly mean Eo was 0.676 mm day−1 (16.8 percent of the mean observed value). (KEY TERMS: reference evaporation; Linacre model; irrigation scheduling.)
GAME‐THEORETIC ANALYSES OF ENFORCEMENT OF ENVIRONMENTAL LAWS AND REGULATIONS1
Authors: Kilgour D. Marc. , Fang Liping , Hipel Keith W.
Published: June 2007

ABSTRACT: Game‐theoretic models are developed for describing and analyzing the inspection and enforcement process, especially as it relates to environmental laws and regulations in North America. Based on these models, systems using irrevocable control orders can be compared to those relying on court determination of guilt and punishment. The cost‐effectiveness of environmental enforcement can be systematically assessed in terms of factors such as the private gains for violators, the costs of inspection, penalties, and the social value of deterring violations. The policy implications of the analysis, especially with reference to environmental protection, are emphasized.
RISK OF EXTREME EVENTS IN A MULTIOBJECTIVE FRAMEWORK1
Authors: Haimes Yacov Y , Lambert James H. , Li Duan
Published: June 2007

ABSTRACT: This paper summarizes advances made in risk‐based decisionmaking in water resources through use of the partitioned multiobjective risk method (PMRM). (Risk is a measure of the probability and severity of adverse effects.) In the PMRM, the risk of extreme events is differentiated from risk involving less extreme damage severity and is evaluated within a multiobjective framework. Study of the extreme‐event risk function f4(*) has addressed the following issues: methods for calculating f4(*); the sensitivity of f4(*) to various parameters, particularly to the partitioning point of the extreme‐event range and the selection of probability density functions; insight provided by the statistics of extremes; and the impact of f4(*) on risk management, for example, in the application of the PMRM to water resources problems. In particular, this paper shares with the reader recent research results on the PMRM, the relationship between the statistics of extremes and the conditional expected value, derived formulas for f4(*), distribution‐free estimates of f4(*), documented case studies in dam safety, and future research directions.
SELECTING TREND TESTS FOR WATER QUALITY SERIES WITH SERIAL CORRELATION AND MISSING VALUES1
Authors: Harcum J. B. , Loftis Jim C. , Ward Robert C.
Published: June 2007

ABSTRACT: The use of nonparametric tests for monotonic trend has flourished in recent years to support routine water quality data analyses. The validity of an assumption of independent, identically distributed error terms is an important concern in selecting the appropriate nonparametric test, as is the presence of missing values. Decision rules are needed for choosing between alternative tests and for deciding whether and how to pre‐process data before trend testing. Several data pre‐processing procedures in conjunction with the Mann‐Kendall tau and the Seasonal Kendall test (with and without serial correlation correction) are evaluated using synthetic time series with generated serial correlation and missing data. A composite test (pre‐testing for serial correlation followed by one of two trend tests) is evaluated and was found to perform satisfactorily.
EFFECTS OF STORM PATTERNS ON RUNOFF HYDROGRAPHS1
Authors: Aron Gert , Adl Iraj
Published: June 2007

ABSTRACT: As an alternative to the conventional single‐peak design storms commonly used in hydrologic practice, a large number of Southeastern Pennsylvania storm events were selected from hourly U.S. National Oceanographic and Atmospheric Administration (NOAA) records, and their temporal distributions were analyzed. From these recorded events, design storms of a typical distribution were developed for storm durations between 6 and 18 hours. All of these generated design storms have two or more peaks. The conventional single peak as well as the “typical” multi‐peak storms were then applied to a simulated watershed. It was found that the multi‐peak storms consistently produced more dispersed hydrographs with lower runoff peaks than the conventional single peak storms.
TRUNCATED DISTRIBUTIONS IN HYDROLOGIC ANALYSIS1
Authors: Loaiciga Hugo A. , Michaelsen Joel , Hudak Paul F
Published: June 2007

ABSTRACT: Truncated samples arise in a variety of hydrologic situations in which certain values of the variables of interest are unobservable. Remotely sensed data, for example, are truncated below the resolution level of the sensor: all objects smaller than the resolution of the instrument are not detected and their characteristics cannot be recorded. Many other situations occur in hydrologic studies where a sampling procedure or method yields truncated samples. The main results on this work on truncated samples are: (1) a general expression for the probability distribution function of a truncated random variable; (2) a description of the effect of truncation on the distribution function of several important probability models and on their parameters; and (3) development of a parameter estimation methodology for parameter estimation from truncated samples.

From the theoretical results of this paper and the analysis of drought‐related data, we have concluded that: (1) truncated sampling can be advantageous, especially when certain ranges of values are difficult or impossible to observe; (2) the developed method for truncated sample analysis leads to efficient and accurate parameter estimation and statistical inference on truncated data; and (3) the developed method for truncated sample analysis can also yield the parameters and the distribution of the entire population when only a subset of that population is observable.
THE ROLE OF AGRICULTURAL GROUNDWATER CONSERVATION IN ACHIEVING ZERO OVERDRAFT IN ARIZONA1
Authors: Cory Dennis C. , Evans Mark E. , Leones Julie P. , Wade James C.
Published: June 2007

ABSTRACT: The elimination of groundwater overdraft was a key feature of the 1980 Arizona Groundwater Management Act. To achieve this goal, the Arizona Department of Water Resources identified several Active Management Areas and developed urban, industrial, and agricultural water conservation plans. This study examines the reductions in groundwater use through agricultural water conservation in the Phoenix Active Management Area (AMA).

Linear programming models are developed to analyze changes in groundwater use and net returns to agriculture over a 38‐year period, 1990 to 2025, for farming areas in the Phoenix AMA. Results indicate that the agricultural conservation program provides only modest groundwater savings under a wide range of scenarios. The low level of savings is partly due to the current economically efficient use of water. Other policy measures such as retiring agricultural land may be necessary if the Phoenix AMA is to meet its overdraft reduction goals; even if urban water conservation goals are met.
GEOGRAPHIC INFORMATION SYSTEMS AS A TOOL IN WATER USE DATA MANAGEMENT1
Authors: Schoolmaster F. Andrew , Marr Paul G.
Published: June 2007

ABSTRACT: The temporal and locational attributes of water use data are ideally suited for analysis using a geographic information system (GIS) approach. A GIS combines spatial database management, statistical analysis, and cartographic modelling capabilities within a computer hardware and software configuration. Texas water use data for selected categories in 1980 and 1986 were analyzed using ARC/INFO to demonstrate the utility of GIS for water resource information management. Examples of data analysis and display are presented to illustrate the effectiveness of cartographic representations to communicate water use data.
MULTIPLICATIVE, SEASONAL ARIMA MODELS FOR LAKE ERIE AND LAKE ONTARIO WATER LEVELS1
Authors: Irvine K. N. , Eberhardt A. J.
Published: June 2007

ABSTRACT: Federal agencies in the U.S. and Canada continuously examine methods to improve understanding and forecasting of Great Lakes water level dynamics in an effort to reduce the negative impacts of fluctuating levels incurred by interests using the lakes. The short term, seasonal and long term water level dynamics of lakes Erie and Ontario are discussed. Multiplicative, seasonal ARIMA models are developed for lakes Erie and Ontario using standardized, monthly mean level data for the period 1900 to 1986. The most appropriate model identified for each lake had the general form: (1 0 1)(0 1 1)12. The data for each lake were subdivided by time periods (1900 to 1942;1 943 to 1986) and the model coefficients estimated for the subdivided data were similar, indicating general model stability for the entire period of record. The models estimated for the full data sets were used to forecast levels 1,2,3, and 6 months ahead for a period of high levels (1984 to 1986). The average absolute forecast error for Lake Erie was 0.049m, 0.076m, 0.091 m and 0.128m for the 1, 2,3, and 6 month forecasts, respectively. The average absolute forecast error for Lake Ontario was 0.058m, 0.095m, 0.120m and 0.136m for the 1,2,3, and 6 month forecasts, respectively. The ARIMA models provide additional information on water level time series structure and dynamics. The models also could be coordinated with current forecasting methods, possibly improving forecasting accuracy.
A RISK‐BASED APPROACH FOR FLOOD CONTROL OPERATION OF A MULTIPURPOSE RESERVOIR1
Authors: Jain S. K. , Yoganarasimhan G. N. , Seth S. M.
Published: June 2007

ABSTRACT: Many approaches are available for operation of a multipurpose reservoir during flood season; one of them is allocation of storage space for flood control. A methodology to determine a reservoir operation policy based on explicit risk consideration is presented. The objective of the formulation is to maximize the reservoir storage at the end of a flood season while ensuring that the risk of an overflow is within acceptable limits. The Dynamic Programming technique has been used to solve the problem. This approach has been applied to develop operation policies for an existing reservoir. The performance of the policy was evaluated through simulation and was found to be satisfactory.
REGIONAL CHEMISTRY OF LAKES IN MASSACHUSETTS 1
Authors: Mattson M. D. , Godfrey P. J. , Walk M. F. , Kerr P. A. , Zajicek O. T.
Published: June 2007

ABSTRACT: We surveyed over 2000 lakes in the State of Massachusetts (1983–1984) to examine the spatial variations in their acid‐base chemistry. Our survey differed from previous surveys by including small lakes and nonpristine urban lakes. For samples collected in October 1983 and 1984, the median acid neutralizing capacity (ANC) was 184 μeq L−1 and 5.9 percent were acidic (ANC≤O). Small lakes (<4 ha) were more likely to be acidic than large lakes. Generally, sulfate was the dominant acidifying agent, although organic anions were dominant in some of the lakes in the Cape Cod Region. The ionic composition of the lakes showed strong regional patterns which appear to be related to geology and human population density. An analysis of variance of ANC shows the six regional categories in the state explain 51 percent of the variance, while a combined general linear model of lake drainage type, color, elevation, size, silica, and hydrogen ion deposition could explain only 4.9 percent of the variation in ANC. Calcium rich, high ionic strength lakes were present in the marble bedrock in the west, and relatively dilute lakes dominated by sodium and chloride were found near the coast. Chloride concentrations were also related to population density, suggesting road salt as a likely contributing source.
LAWS AND PROGRAMS FOR CONTROLLING NONPOINT SOURCE POLLUTION IN FOREST AREAS1
Authors: Brown Thomas C. , Brown Douglas , Binkley Dan
Published: June 2007

ABSTRACT: Recent federal legislation strengthened nonpoint source pollution regulations and helped to support and standardize pollution control efforts. A comprehensive review of current state and federal programs for forest areas reveals a substantial increase in agency water quality protection activities. These new efforts emphasize monitoring to assess the use and effectiveness of best management practices (BMPs). Recent monitoring reveals that BMP use is increasing and that such use typically maintains water quality within standards. However, information is generally lacking about the cost effectiveness of BMP programs. Carefully designed and executed monitoring is the key to better specification of BMPs and more cost effective water quality protection. (KEY TERMS: water quality; nonpoint source pollution; water law; watershed management; forestry; best management practices.)
PREDICTING WILDERNESS SNOW WATER EQUIVALENT WITH NONWILDERNESS SNOW SENSORS1
Authors: McGurk Bruce J. , Edens Thaddeus J. , Azuma David L.
Published: June 2007

ABSTRACT: Ten pairs of snow sensors were analyzed to investigate the feasibility of predicting snow water equivalent at high‐elevation, telemetered snow sensor sites from lower‐elevation sensors. The need for this analysis stems from an agreement between the California Department of Water Resources and the USDA Forest Service to temporarily allow snow sensors in California's wilderness areas so that a predictive relationship can be developed. After 10 or 15 years, the agreement calls for the sensors to be removed. Initial efforts to a priori select sensor pairs were based on proximity, colocation within a basin, and annual precipitation amount, but regression yielded poor fits (R2 < 0.65) and high standard errors in eight of the ten cases. Analysis of the results suggested that eleva‐tional similarity was the most important selection criteria, and that all available sensors near the target site should be analyzed via a regression screening. Using elevation for selection and the regression screening, five sensors that initially had poor fits were reanalyzed. Each of the five sensors was paired with between two and five new sensors, and R2 values improved between 27 and 46 percent. Various data smoothing and editing algorithms were evaluated, but they rarely resulted in improved fits.
SPATIAL ANALYSIS FOR MONTHLY RAINFALL IN SOUTH FLORIDA1
Authors: Abtew W. , Obeysekera J. , Shih G.
Published: June 2007

ABSTRACT: Several methods have been developed to interpolate point rainfall data and integrate areal rainfall data from any network of stations. From previous studies, it can be concluded that models for spatial analysis of rainfall are dependent on topography, area of analysis, type of rainfall, and density of gauging network. The purpose of this study is to evaluate a set of six appropriate models for point and areal rainfall estimations over a 4000 square mile area in South Florida.

In this study, a case of developing spatial continuity model for monthly rainfall from a database that had various lengths of records and missing data is documented. The spatial correlation and variogram models for monthly rainfall were developed. Six methods of spatial interpolation were applied and the results validated with historical observations. The results of the study indicate that the multiquadric, kriging, and optimal interpolation schemes are the best three methods for interpolation of monthly rainfall within the study area. The optimal and kriging methods have the advantage of providing estimates of the error of interpolation. The optimal interpolation method uses the spatial correlation function and the kriging method uses the variogram function. The two spatial functions are related. Either of the two methods provide good estimates of monthly point and areal rainfall in the study area.
RURAL HOUSEHOLD RESPONSE TO WATER CONTAMINATION IN WEST VIRGINIA1
Authors: Collins Alan R. , Steinback Scott
Published: June 2007

ABSTRACT: About one‐third of all West Virginians obtain domestic water from private water wells. In this research, mail and telephone surveys were used to investigate household responses to bacteria, mineral, and organic chemical contamination of domestic water supplies. Of households who were informed of contamination and acknowledged the problem, over 85 percent took action to avoid exposure to water contamination problems. The most common action was to clean and/or repair the water system (55.9 percent of valid surveys). Approximately 45 percent of households made investments of either a water treatment system, a new water source, or correction of contamination source. The average, annual economic cost of rural household actions was $320 for bacteria, $357 for minerals, and $1,090 for organic contamination. These economic costs represent a lower bound estimate for rural household willingness‐to‐pay (WTP) for a reduction in domestic water contamination from government action. On average, investment actions had lower annual economic costs than noninvestment actions of boiling and hauling water so that households who undertook investment actions in response to water contamination would have a lower WTP for government action to reduce water contamination.

When effectiveness of water treatment systems was evaluated, treatment systems which require minimal household maintenance were found to reduce exposure to water contamination to safe levels as households intended when they installed the system. Treatment systems which were commonly ineffective included those which required continual maintenance (e.g., chiorinators) or were not designed to solve the contaminant problem for which they were purchased (e.g., filter systems for bacteria).