bluuebunny/crossref_metadata_2025 huggingface dataset:
A PARTICIPATORY APPROACH TO WATERSHED MANAGEMENT: THE BRAZILIAN SYSTEM1
Authors: Porto Monica , La Laina Porto Rubem , Azevedo Luiz Gabriel T.
Published: June 2007

ABSTRACT: Brazil is currently facing the challenge of implementing a new water resources management system to promote the rational and sustainable use of the country's waters. This system is based on the following principles of water management: (2) stakeholders' participation; (2) the watershed as the planning and management unit; and (3) the economic value of water. Stakeholders' participation and the involvement of civil society in the decision making process is guaranteed by permanent seats in the watersheds' management committees. These committees are the highest decision level for the establishment of water policy and for planning its use. The executive branch of the committees is the watershed agency or the water agency. This paper presents the recently approved Brazilian water resources management system and discusses the participatory approach followed to validate and to ensure prompt response to decisions regarding water use by all stakeholders. The formulation of the National Water Law (January/1998) was also supported by extensive consultation with civil society, professional associations, state and municipal governments as well as with federal governmental agencies and private sector organizations. It also presents an overview of the formulation of the National Water Law. Finally, as watershed committees have been created and are already operating in a limited number of watersheds, some of the major obstacles to the success of the new system are discussed along with alternatives for overcoming such obstacles.
INTEGRATING DIFFUSEINONPOINT POLLUTION CONTROL AND WATER BODY RESTORATION INTO WATERSHED MANAGEMENT1
Authors: Novotny Vladimir
Published: June 2007

ABSTRACT: The objective of water quality/watershed management is attainment of water quality goals specified by the Clean Water Act. The Total Maximal Daily Load (TMDL) planning process is a tool to set up watershed management. However, TMDL methodologies and concepts have several problems, including determination of Loading Capacity for only low flow critical periods that preclude consideration of wet weather sources in water quality management. Research is needed to develop watershed pollutant loading and receiving waters Loading Capacity models that will link wet and dry weather pollution loads to the probability of the exceedence of water quality standards. The long term impact of traditional Best Management Practices as well as ponds and wetlands, must be reassessed to consider long term accumulation of conservative toxic compounds. Socioeconomic research should focus on providing information on economic and social feasibility of implementation of additional controls in water quality limited watersheds.
QUANTIFICATION OF THE WATER BUDGET AND NUTRIENT LOADING IN A SMALL PEATLAND1
Authors: Drexier Judy Z. , Bedford Barbara L. , DeGaetano Arthur T , Siegel Donald I.
Published: June 2007

ABSTRACT: Few water budgets exist for specific types of wetlands such as peatlands, even though such information provides the basis from which to investigate linkages between wetlands and upland ecosystems. In this study, we first determined the water budget and then estimated nutrient loading from an upland farm field into a 1.5 ha, kettle‐block peatland. The wetland contains highly anisotropic peat and has no distinct, active layer of groundwater flow. We estimated the depth of the active layer using Fick's law of diffusion and quantified groundwater flow using a chemical mass balance model. Evapotranspiration was determined using MORECS, a semi‐physical model based on the Penman‐Monteith approach. Precipitation and surface outflow were measured using physical means. Groundwater provided the major inflow, 84 percent (44,418 m3) in 1993 and 88 percent (68,311 m3) in 1994. Surface outflow represented 54 percent (28,763 m3) of total outflows in 1993 and 48 percent (37,078 m3) in 1994. A comparison of several published water budgets for wetlands and lakes showed that error estimates for hydrologic components in this study are well within the range of error estimates calculated in other studies. Groundwater inflow estimates and nutrient concentrations of three springs were used to estimate agricultural nutrient loading to the site. During the study period, nutrient loading into the peatland via groundwater discharge averaged 24.74 kg K ha‐1, 1.83 kg total inorganic P had, and 21.81 kg NO3‐N ha‐1.
SELENIUM BUDGETS FOR LAKE POWELL AND THE UPPER COLORADO RWER BASIN1
Authors: Engberg Richard A.
Published: June 2007

ABSTRACT: A selenium budget for Lake Powell, Utah‐Arizona was determined based on selenium loads at the principal stream input sites to and the output site from the lake. Based on data collected during 1985‐1994, 83 percent of the selenium entering Lake Powell is accounted for at the output site. The rest of the selenium may be incorporated by lake sediment or used by the biota. Considerably more selenium per unit area is produced from the Colorado River Basin above the Colorado River‐Green River confluence than from the Green River Basin and the San Juan River Basin combined. The Gunnison River Basin and the Grand Valley in Colorado produce an estimated 31 and 30 percent of the selenium that reaches Lake Powell, respectively. Irrigation‐related activities are thought to be responsible for mobilizing 71 percent of the selenium that reaches Lake Powell. Selenium concentrations in water at Imperial Dam on the Colorado River upstream of the United States‐Mexico international border are similar to those at the output site of Lake Powell. Therefore, most selenium observed in downstream areas of the Colorado River therefore probably is derived mostly from the Colorado River Basin above Lake Powell.
CHEMICAL CONSTITUENTS IN STORM FLOW VS. DRY WEATHER DISCHARGES IN CALIFORNIA STORM WATER CONVEYANCES1
Authors: Duke L. Donald , Lo Thomas S. , Turner Michelle W
Published: June 2007

ABSTRACT: This research evaluated concentration data for selected water quality parameters in selected California urban separate storm sewer systems during storm event discharges and during dry weather conditions. We used existing monitoring data from multiple regulatory agencies and municipalities originally collected for compliance or local characterization, which allowed systematic assessment of seasonal patterns over a wide region. Long term mean concentration for most parameters in most streams was higher during storm discharges than during dry weather flows to at least 95 percent confidence in 20 of 45 comparative evaluations, and lower statistical confidence in 22 other comparisons. Some regional differences emerged: in four evaluated streams in the San Francisco Bay Area, total concentration of lead, copper and zinc were lower during dry weather than during storm flows to at least 99.9 percent confidence, with only one exception; while the other four evaluated California streams showed the same tendency, but to much lower statistical confidence.
MODELING THE IMPACT OF SUBSURFACE NUTRIENT FLUX ON WATER QUALITY IN THE LOWER TRUCKEE RWER, NEVADA1
Authors: Warwick J. J. , Cockrum D. , McKay A.
Published: June 2007

ABSTRACT: The impacts of regional groundwater quality and local agricultural activities on in‐stream water quality in the Lower Truckee River, Nevada, were assessed through a detailed program of monitoring and computer simulation. An agricultural diversion and return‐flow were monitored in great detail to determine mass loading rates of nutrients from agriculture in the area. Once characterized, the cumulative impacts of agricultural diversions and return‐flows were evaluated using the Water Quality Assessment Program (WASP) to model nitrogen, phosphorus, periphyton, and dissolved oxygen. Monitoring showed that a significant proportion of the water diverted for agricultural purposes returned to the river as surface point return‐flow (estimated at 13.9 percent $ 0.1 percent), and as groundwater diffuse return‐flow (estimated at 27 percent $ 6 percent). Modeling efforts demonstrated the significant effect of assumed regional groundwater quality (nitrate) upon predicted periphyton growth and associated diel fluctuations of dissolved oxygen.
SEDIMENT AND NITROGEN TRANSPORT IN GRASS FILTER STRIPS1
Authors: Mendez Aida , Dillaha Theo A. , Mostaghimi Saied
Published: June 2007

ABSTRACT: An 18‐month field experiment was conducted to evaluate the effectiveness of grass filter strips in removing sediment and various nitrogen species from runoff. Runoff was collected from six 3.7 m wide experimental plots with 24.7 m long runoff source areas. Two plots had 8.5 m filters, two plots had 4.3 m filters, and two plots had no filters. Runoff was analyzed for total suspended solids (TSS), total Kjeldahl nitrogen (TKN),. filtered TKN (FTKN), NH4+‐N, and NO3‐N. The Mann‐Kendall nonparametric test for trend (changes in filter effectiveness over time) indicated that there were no trends in the yields and concentrations of TSS, NO3‐‐N, NH4‐N, TKN, and FTKN for the 8.5 m filter over time. For the shorter 4.3 m filters, there were significant upward trends in TKN yield and downward trends in TSS, NH4‐N, and FTKN concentrations, indicating that trapping efficiency may have started changing with time. The Kruskal‐Wallis test indicated that the 8.5 m filters reduced median yields and concentrations of TSS and all N species, but the 4.3 m filters only reduced the median yields and concentrations of TSS, NH4+‐N, TKN, and the median concentration of FTKN. The 8.5 and 4.3 m filters reduced contaminate yields and concentrations from 42 to 90 percent and from 20 to 83 percent, respectively.
DEVELOPING CONFIDENCE IN CONCRETE REVETMENT PRODUCTS FOR BANK STABILIZATION1
Authors: Leech James R. , Abt Steven R. , Thornton Christopher I. , Combs Phil G.
Published: June 2007

ABSTRACT: There is a need to provide flood protection while maintaining stable bed and bank conditions in the riverine system, to stabilize earth embankment dams and spiliways, and to stabilize highway or railway embankments and levee systems. One approach to providing erosion protection and stabilization of channel banks, embankments and spill conveyances is with articulated concrete block systems. Numerous articulated concrete block systems are available for bank stabilization. However, prior to field installations few means are available to evaluate how well these block systems perform. To assist the designer in predicting site specific suitability, a series of hydraulic testing protocols have been developed to analyze block system performance. Two articulated block system testing protocols are presented to indicate how block hydraulic characteristics may be determined and provide performance assurance to both the designer and the owner.
DETERMINATION OF UNCONFINED AQUIFER HYDRAULIC PROPERTIES FROM RECOVERY TEST DATA1
Authors: Chen Xunhong
Published: June 2007

ABSTRACT: This paper analyzes the sensitivity of drawdown to four hydraulic parameters in unconfined aquifers: horizontal and vertical hydraulic conductivity Kr and Kz, storage coefficient S, and specific yield Sy. Sensitivity coefficients indicate that the sensitivity vanes with time for each aquifer parameter, and Kr, Kz, S, and Sy are identifiable from recovery test data. An inverse method was used to calculate the four parameters from residual drawdowns. Results of application examples demonstrate that residual data provide valid information in the determination of unconfined aquifer hydraulic parameters.
POLICY OBJECTWES AND ECONOMIC INCENTWES FOR CONTROLLING AGRICULTURAL SOURCES OF NONPOINT POLLUTION1
Authors: Horan Richard D. , Ribaudo Marc O.
Published: June 2007

In this paper, we review the physical characteristics of agricultural non point pollution and discuss the implications for setting appropriate pollution control objectives and designing incentive‐based pollution control policies. First, we discuss that policy objectives must be designed carefully to ensure positive economic net benefits can be expected from pollution control. Next, we review several classes of incentives and recommend the use of design‐based incentives (i.e., incentives based on variable input use, management practices, and land use) for controlling non point pollution. Cost‐effectiveness requires that incentives elicit three types of responses from farmers: (1) use variable inputs at appropriate levels, (2) adopt appropriate management practices, and (3) make appropriate land use decisions at the extensive margin of production. If a set of incentives fails to induce the correct responses, the resulting runoff levels and hence ambient pollution levels and damages will be too large relative to policy goals. A review of existing programs suggests that greater program coordination and improved targeting of incentives are needed for further water quality improvements. Alternatively, properly designed market‐based systems may be effective alternatives. These systems would reduce overall pollution control costs by allowing markets to allocate point source and non point source control costs more efficiently.
QUANTIFYING MODEL OUTPUT UNCERTAINTY DUE TO SPATIAL VARIABILITY OF RAINFALL1
Authors: Chaubey I. , Haan C. T. , Salisbury J. M. , Grunwald S.
Published: June 2007

Traditionally in the application of hydrologic/water quality (H/WQ) models, rainfall is assumed to be spatially homogeneous and is considered not to contribute to output uncertainty. The objective of this study was to assess the uncertainty induced in model outputs solely due to rainfall spatial variability. The study was conducted using the AGNPS model and the rainfall pattern captured by a network of 17 rain gauges. For each rainfall event, the model was run using the rainfall captured by each rain gauge, one at a time, under the assumption of rainfall spatial homogeneity. A large uncertainty in the modeled outputs resulted from the rainfall spatial variability. The uncertainty in the modeled outputs exceeded the input rainfall uncertainty. Results of this study indicate that spatial variability of rainfall should be captured and used in H/WQ models in order to accurately assess the release and transport of pollutants. A large uncertainty in the model outputs can be expected if this rainfall property is not taken into account.
USING FIELD SCALE MODELS TO PREDICT PEAK FLOWS ON AGRICULTURAL WATERSHEDS1
Authors: Gowda Prasanna H. , Ward Andy D. , White Dale A. , Baker David B. , Lyon John G.
Published: June 2007

The goal of this study was to develop a methodology for generating storm hydrographs at a watershed scale based on daily runoff estimates from a field scale model. The methodology was evaluated on a small agricultural watershed using the ADAPT field scale process model. A comparison of observed and predicted peak flows for 11 of the largest events that occurred in a three year period gave r2 values of 0.84, 0.82, and 0.81 when the watershed was subdivided into 1, 5, and 10 sub watersheds. However, all other statistical measures improved when the watershed was subdivided into at least five sub watersheds. Guidelines need to be developed on the use of the procedure but it first needs to be evaluated on several watersheds that exhibit a range in sizes, land uses, slopes, and soil properties.
COMPARISON OF MODELS FOR ESTIMATING FLOOD QUANTILES IN NEW HAMPSHIRE AND VERMONT1
Authors: Dingman S. Lawrence , Palaia Kevin J.
Published: June 2007

We develop and compare three regression models for estimating flood quantiles at ungaged stream reaches in New Hampshire and Vermont. These models emerge from systematic analysis and validation of relations between flood magnitude and six candidate predictors reflecting basin size, topography, and climate and channel size at 36 gaging stations with record lengths exceeding 20 years. Of the candidate predictors, bank full width is most highly correlated with flood magnitude and the best prediction equation is based on width. Thus channel geometry is closely related to the current hydrologic regime in spite of geologically recent glaciation and apparently non‐alluvial bank materials. We also develop models that use information obtainable from maps or GIS. The best of these uses drainage area and drainage‐basin elevation as predictors, but it is substantially less precise than the width‐based relation. A third relation using only drainage area as a predictor is even less precise but may be useful for some purposes. No other single predictors or combinations yielded useful predictions, although some had been included in previously‐established models for the region. Model comparison included examination of residuals generated by regression using one‐at‐a‐time suppression of data points and comparison with precision obtainable with gaging records of varying lengths.
CLIMATE CHANGE AND EXTRATROPICAL STORMINESS IN THE UNITED STATES: AN ASSESSMENT1
Authors: Hayden Bruce P.
Published: June 2007

ABSTRACT: Climate change due to enrichment of the atmosphere with carbon dioxide is projected to change the circulation of the atmosphere, increase its moisture content, warm the surface layers, and increase precipitation. Extratropical storms are the intermediate agent in mid‐latitudes between changes in the circulation of the atmosphere and surface water resources. The climatology of extratropical storms for the period 1885–1996 is presented, and major changes in storminess are detected across much of North America. General Circulation Model (GCM) projections of storm frequency and storm track are found to have little in common with the observed pattern of storms and evidence no systematic changes in response to an enrichment of the atmosphere with carbon dioxide.
WEATHER AND CLIMATE EXTREMES, CLIMATE CHANGE, AND PLANNING: Views of Community Water System Managers in Pennsylvania's Susquehanna River Basin1
Authors: O'Connor Robert E. , Yarnal Brent , Neff Rob , Bord Richard , Wiefek Nancy , Reenock Christopher , Shudak Robin , Jocoy Christine L. , Pascals Peter , Knight C. Gregory
Published: June 2007

ABSTRACT: This research examines the sensitivity and vulnerability of community water systems (CWSs) to weather and climate in the Pennsylvania portion of the Susquehanna River Basin. Three key findings emerge from a survey of 506 CWS managers. First, CWSs are sensitive to extreme weather and climate, but that sensitivity is determined more by type of system than system size. CWSs that rely partly or wholly on surface water face more disruptions than do groundwater systems. Larger systems have more problems with flooding, and size is not a significant determinant of outages from storms or disruptions from droughts. Second, CWS managers are unsure about global warming. Few managers dismiss global warming; most think global warming could be a problem but are unwilling to consider it in their planning activities until greater scientific certainty exists. Third, the nature of the CWS, its sensitivity to weather and climate, and projected risks from weather and climate are insignificant determinants of how managers plan. Experienced, full‐time managers are more likely to consider future weather and climate scenarios in their planning, while inexperienced and part‐time managers are less likely to do so. Implications of these findings include support for efforts to move away from surface water, for clear communication of climate change information, and for the hiring and retention of full‐time professional CWS managers.
GENERAL‐CIRCULATION‐MODEL SIMULATIONS OF FUTURE SNOWPACK IN THE WESTERN UNITED STATES1
Authors: McCabe Gregory J. , Wolock David M.
Published: June 2007

ABSTRACT: April 1 snowpack accumulations measured at 311 snow courses in the western United States (U.S.) are grouped using a correlation‐based cluster analysis. A conceptual snow accumulation and melt model and monthly temperature and precipitation for each cluster are used to estimate cluster‐average April 1 snowpack. The conceptual snow model is subsequently used to estimate future snowpack by using changes in monthly temperature and precipitation simulated by the Canadian Centre for Climate Modeling and Analysis (CCC) and the Hadley Centre for Climate Prediction and Research (HADLEY) general circulation models (GCMs). Results for the CCC model indicate that although winter precipitation is estimated to increase in the future, increases in temperatures will result in large decreases in April 1 snowpack for the entire western U.S. Results for the HADLEY model also indicate large decreases in April 1 snowpack for most of the western US, but the decreases are not as severe as those estimated using the CCC simulations. Although snowpack conditions are estimated to decrease for most areas of the western US, both GCMs estimate a general increase in winter precipitation toward the latter half of the next century. Thus, water quantity may be increased in the western US; however, the timing of runoff will be altered because precipitation will more frequently occur as rain rather than as snow.
GREAT LAKES WATER RESOURCES: CLIMATE CHANGE IMPACT ANALYSIS WITH TRANSIENT GCM SCENARIOS1
Authors: Chao Philip
Published: June 2007

ABSTRACT: The U.S. Army Corps of Engineers conducted an assessment of Great Lakes water resources impacts under transient climate change scenarios. The integrated model linked empirical regional climate downscaling, hydrologic and hydraulic models, and water resource use sub‐models. The water resource uses include hydropower, navigation, shoreline damages, and wetland area. The study is unique in that both steady‐state 2°CO2 and transient global circulation model (GCM) scenarios were used and compared to each other. The results are consistent with other impact studies in that high scatter in regional climate among the GCM scenarios lead to high uncertainty in impacts. Nevertheless, the transient scenarios show that in the near‐term (approximately 20 years) significant changes could occur. This result only adds to the urgency of creating more flexible and robust management of water resources uses.
FRESH‐WATER LENS FORMATION IN AN UNCONFINED BARRIER‐ISLAND AQUIFER1
Authors: Collins William H. , Easley Dale H.
Published: June 2007

ABSTRACT: Cone‐penetrometer testing and computer modeling were utilized to investigate factors controlling fresh‐water lens formation at Grand Isle, Louisiana. Measurements of tip resistance, sleeve friction, and electrical conductivity were recorded with depth to permit classification of sediment type and to determine thickness of the fresh‐water lens and transition zone. Cone‐penetrometer testing provided virtually continuous determinations of change in sediment type and ground‐water salinity at a resolution rarely achieved using conventional drilling and water sampling techniques.

Three sand bodies are present, each separated by a clay layer. The fresh‐water lens is thinner in the center of the island than on the flanks. Fresh‐water lens thickness is limited by a clay layer which prohibits downward movement of significant volumes fresh water. The transition zone from fresh water to salt water varies in thickness, being thinnest near the Gulf of Mexico and thickest where silt and clay interfinger with the upper sand.

Both the thickness of the fresh‐water lens and the shape of the transition zone differ from that predicted by theoretical models. Calibration of STJTRA, a variable‐density solute‐transport model, indicates that permeability variations are the dominant control on formation of the fresh‐water lens.
A 396‐YEAR RECONSTRUCTION OF PRECIPITATION IN SOUTHERN JORDAN1
Authors: Touchan Ramzi , Meko David , Hughes Malcolm K
Published: June 2007

ABSTRACT: Water resources are the lifeblood of the Near East region. Careful planning and management of water resources in dry land regions requires information on the likelihood of extreme events, especially prolonged drought. It is essential to understand the variability of climate on time scales of decades to centuries to assign reasonable probabilities to such events. Tree‐ring analysis is one way to increase our knowledge of the climate variability beyond the short period covered by the instrumental data. In this paper, we reconstruct October‐May precipitation from a Juniperus phoenicia tree‐ring chronology in southern Jordan to gain a long‐term (A.D. 1600–1995) perspective on runs of dry years and on time series fluctuations in precipitation averaged over several years. The reconstruction equation derived by regression of log‐transformed precipitation on tree‐ring indices explains 44 percent of the variance of observed precipitation. The longest reconstructed drought, as defined by consecutive years below a threshold of 217.4 mm, was four years, compared with three years for the 1946–95 instrumental data. A Monte Carlo analysis designed to account for uncertainty in the reconstruction indicates a lower than 50 percent chance that the region has experienced drought longer than five years in the past 400 years.
RUNOFF OF METALS FROM ALUM‐TREATED HORSE MANURE AND MUNICIPAL SLUDGE1
Authors: Edwards D. R. , Moore P. A. , Workman S. R. , Busheé E. L.
Published: June 2007

ABSTRACT: Land application of organic soil amendments can increase runoff concentrations of metals such as Fe and Zn, metalbids such as B and As, and non‐metals such as P and S that have the potential for causing adverse environmental impacts. Aluminum sulfate, or alum (Al2(SO4)3*(14H2O), can reduce concentrations of some materials in runoff from sites treated with organic amendments. The objectives of this study were to (a) quantify concentrations of selected constituents (Al, As, B, Ca, Cd, Co, Fe, K, Mg, Mn, Mo, Na, P, Pb, 5, Se, Ti, and Zn) in runoff from plots treated with horse manure (mixed with stall bedding) and municipal sludge, (b) assess runoff quality effects of alum addition to those treatments, and (c) determine time variations in concentrations of the constituents. Horse manure and municipal sludge were applied to twelve 2.4 by 6.1 m fescue plots (six each for the manure and sludge). Alum was added to three of the manure‐treated and three of the sludge‐treated plots. Simulated rainfall (64 mm/h) was applied to the 12 treated plots and to three control (no treatment) plots. The first 0.5 h runoff was sampled and analyzed for the constituents described above. Addition of manure or sludge had no effect on runoff concentrations of the majority of constituents. In some cases (e.g., Al, As, Fe, Zn), however, concentrations were near or in excess of threshold values recommended for marine wildlife protection. Alum addition increased runoff of Al, Ca, K, and 5, due likely to its composition and by the addition of lime to counteract the acidity of alum. Concentration decreases of more than 50 percent were noted for P for the horse manure treatment. No alum effect was detected for P in runoff from the sludge‐treated plots, possibly due to relatively stable P forms in the sludge. Runoff concentrations of Al, As, Fe, K, Mn, and P followed an approximately first‐order decline with respect to time. Runoff concentrations of Ca and 5, however, peaked during the second runoff sample (four minutes following initiation of runoff), suggesting that differences in mobility and/or transport mechanisms exist among the materials investigated.
ELISA AND GC/MS ANALYSIS OF PESTICIDE RESIDUES IN NORTH CAROLINA1
Authors: Walker Ashlee E. , Holman Robert E. , Leidy Ross B.
Published: June 2007

ABSTRACT: Studies were conducted to analyze the presence of 11 pesticide residues in 12 surface waters in the Piedmont and coastal plain regions of North Carolina. Samples were assayed using enzyme‐linked immunosorbent assays (ELISAs). All ELISA results of one part per billion (ppb, μg/L) or greater were confirmed using gas chromatography/mass spectrometry (GCIMS). ELISA detection limits were approximately an order of magnitude higher than GCJMS methods. Of the 5,035 analytical results from 742 surface water samples, atrazine was detected in approximately 45 percent of the samples, five of which were at or above the Maximum Contaminant Level (MCL) of 3‐ppb. Metolachlor was detected in 64 percent of the samples. Aldicarb, 2,4‐D, chlorpyrifos, and chlorothalonil were also detected, and each was found in less than 12 percent of the samples. The remaining pesticides, including carbaryl, acetochior, methomyl, carbofuran, and alachlor, were not detected during the study period.
EFFECTS OF CONTROLLED DRAINAGE ON STORM EVENT HYDROLOGY IN A LOBLOLLY PINE PLANTATION1
Authors: Amatya D. M. , Gregory J. D. , Skaggs R. W.
Published: June 2007

ABSTRACT: A paired watershed approach was utilized to study the effects of three water management regimes on storm event hydrology in three experimental watersheds in a drained loblolly pine (Pinus taeda L.) plantation in eastern North Carolina. The regimes were: (1) conventional drainage, (2) controlled drainage (CD) to reduce outflows during spring fish recruitment, and (3) controlled drainage to reduce outflows and conserve water during the growing season. Data from two pit‐treatment years and three years of CD treatment with raised weirs at the watershed outlet are presented. CD treatment resulted in rises in water table elevations during the summer. But the rises were small and short‐lived due to increased evapotranspiration (ET) rates as compared to the spring treatment with lower ET demands. CD treatment had no effect on water tables deeper than 1.3 m. CD treatments, however, significantly (α= 0.05) reduced the stoning outflows for all events, and peak outflow rates for most of the events depending upon the outlet weir level. In some events, flows did not occur at all in watersheds with CD. When event outflows occurred, duration of the event was sharply reduced because of reduced effective ditch depth. Water table depth at the start of an event influenced the effect of CD treatment on storm event hydrology.
ESTIMATION OF THE HIEC1 LOSS PARAMETERS FOR ROUTING THE PROBABLE MAXIMUM FLOOD1
Authors: Boufadel Michel C.
Published: June 2007

ABSTRACT: Twenty storm events were used to select design values of the HEC1 loss parameters STRTL and CNSTL in order to route the probable maximum flood, PMF, through the Englewood watershed, Ohio. The parameter STRTL represents the initial volume of water lost due to interception and incomplete saturation of the soil prior to the storm. The parameter CNSTL represents a continuous loss rate and depends only on the watershed. When optimized from each storm event, STRTL varied between 0.0 and 3.4 inches with an average of 1.0 inch; CNSTL varied between 0.02 and 0.26 inch/hour, and it followed a normal probability distribution with a mean of about 0.1 inch/hour. The absence of correlation between optimum CNSTL values and each of total rainfall, total loss, and runoff duration supported the selection of the mean CNSTL as a design value. PMF routing through the Englewood watershed revealed that the PMF at the outlet is not sensitive to STRTL, but highly affected by CNSTL variations. The insensitivity to STRTL was due to the presence of a dam at the outlet of the watershed that caused the buildup of water in the watershed, thereby masking the storage effect of STRTL. The peak PMF increased by about 27 percent when the design CNSTL was decreased to 0.05 inch! hour, and decreased by about 18 percent when the design CNSTL was increased to 0.15 inch/hour.
SURFACE WATER WITHDRAWAL ALLOCATION AND TRADING SYSTEMS FOR TRADITIONALLY RIPARLAN AREAS1
Authors: Wollmuth Jessica Cragan , Eheart J. Wayland
Published: June 2007

ABSTRACT: There is a growing need for water regulations in states traditionally managed by the riparian doctrine. Several states have passed water laws to control withdrawals from streams. Few, if any, however, have set up consistent and defensible methods for allocating water to users. This paper explores several methods for such allocations, examining each in detail and offering numerical examples that compare each on the basis of economic efficiency and effectiveness for maintaining critical stream‐flow standards. This work is part of a study to assess the vulnerability of Midwestern streams to climate change and, especially, surface supplied irrigation spawned by such climate change. The results suggest that it is possible to implement regulations that at once (1) are consistent with the riparian doctrine; (2) control the hydrological and ecological impacts of off stream withdrawals effectively; and (3) preserve the primary economic functions of those withdrawals, including minimizing economic risk. The results further suggest that trading of water permits improves the latter two objectives, but only if both the regulatory system and permit are well‐designed. On the other hand, in the absence of regulations, or under poorly designed regulations, streamflows, and therefore aquatic ecosystems, could be quite vulnerable.
CLIMATE CHANGE: POTENTIAL IMPACTS AND INTERACTIONS IN WETLANDS OF THE UNTTED STATES1
Authors: Burkett Virginia , Kusler Jon
Published: June 2007

ABSTRACT:Wetlands exist in a transition zone between aquatic and terrestrial environments which can be altered by subtle changes in hydrology. Twentieth century climate records show that the United States is generally experiencing a trend towards a wetter, warmer climate; some climate models suggest that this trend will continue and possibly intensify over the next 100 years. Wetlands that are most likely to be affected by these and other potential changes (e.g., sea‐level rise) associated with atmospheric carbon enrichment include permafrost wetlands, coastal and estuanne wetlands, peat lands, alpine wetlands, and prairie pothole wetlands. Potential impacts range from changes in community structure to changes in ecological function, and from extirpation to enhancement. Wetlands (particularly boreal peat‐lands) play an important role in the global carbon cycle, generally sequestering carbon in the form of biomass, methane, dissolved organic material and organic sediment. Wetlands that are drained or partially dried can become a net source of methane and carbon dioxide to the atmosphere, serving as a positive biotic feedback to global warming. Policy options for minimizing the adverse impacts of climate change on wetland ecosystems include the reduction of current anthropogenic stresses, allowing for inland migration of coastal wetlands as sea‐level rises, active management to preserve wetland hydrology, and a wide range of other management and restoration options.
A COMPARISON OF DELTA CHANGE AND DOWNSCALED GCM SCENARIOS FOR THREE MOUNTAINOUS BASINS IN THE UNITED STATES1
Authors: Hay Lauren E. , Wilby Robert L. , Leavesley George H.
Published: June 2007

ABSTRACT: Simulated daily precipitation, temperature, and runoff time series were compared in three mountainous basins in the United States: (1) the Animas River basin in Colorado, (2) the East Fork of the Carson River basin in Nevada and California, and (3) the Cle Elum River basin in Washington State. Two methods of climate scenario generation were compared: delta change and statistical downscaling. The delta change method uses differences between simulated current and future climate conditions from the Hadley Centre for Climate Prediction and Research (HadCM2) General Circulation Model (GCM) added to observed time series of climate variables. A statistical downscaling (SDS) model was developed for each basin using station data and output from the National Center for Environmental Prediction/National Center for Atmospheric Research (NCEPINCAR) reanalysis regridded to the scale of HadCM2. The SDS model was then used to simulate local climate variables using HadCM2 output for current and future conditions. Surface climate variables from each scenario were used in a precipitation‐runoff model. Results from this study show that, in the basins tested, a precipitation‐runoff model can simulate realistic runoff series for current conditions using statistically down‐scaled NCEP output. But, use of downscaled HadCM2 output for current or future climate assessments are questionable because the GCM does not produce accurate estimates of the surface variables needed for runoff in these regions. Given the uncertainties in the GCMs ability to simulate current conditions based on either the delta change or downscaling approaches, future climate assessments based on either of these approaches must be treated with caution.
AN ORGANIZED SIGNAL IN SNOWMELT RUNOFF OVER THE WESTERN UNITED STATES1
Authors: Peterson D. H. , Smith R. E. , Dettinger M. D. , Cayan D. R. , Riddle L.
Published: June 2007

ABSTRACT: Daily‐to‐weekly discharge during the snowmelt season is highly correlated among river basins in the upper elevations of the central and southern Sierra Nevada (Carson, Walker, Tuolumne, Merced, San Joaquin, Kings, and Kern Rivers). In many cases, the upper Sierra Nevada watershed operates in a single mode (with varying catchment amplitudes). In some years, with appropriate lags, this mode extends to distant mountains. A reason for this coherence is the broad scale nature of synoptic features in atmospheric circulation, which provide anomalous insolation and temperature forcing that span a large region, sometimes the entire western U.S. These correlations may fall off dramatically, however, in dry years when the snowpack is spatially patchy.
SPATIALLY DISTRIBUTED MODELING OF STREAM FLOW DURING STORM EVENTS1
Authors: Gorokhovich Yuri , Khanbilvardi Reza , Janus Lorraine , Goldsmith Victor , Stern David
Published: June 2007

ABSTRACT: The purpose of this paper is to present a new approach for the spatially distributed modeling of water flow during storm events. Distributed modeling of flow during storm events is an important basis for any environmental modeling, including turbidity or sediment transport. During the initial phase of a rainstorm, surface runoff is the main contributor of flow. To provide the spatial components for distributed hydrological modeling a Geographic Information System (GIS) was used to map and visualize contributing areas around a stream channel. Stream segments were defined using the hydrologic response unit (HRU) concept. Lateral flows were derived from GIS output for each segment of the stream and at each time interval of the rain storm and were routed using the kinematic routing equation. This approach is new in hydrological modeling and can be used to enhance many existing simulations. The model is also unique in the fine time scale (i.e., intervals are on the order of minutes). Model results showed good correlation with measured discharge values; however, further studies of contributing area behavior, its relationship with soil types and slope categories, and the influence of watershed size are needed to improve model performance. This model will be used in the future as the basis to model turbidity in streams.
DEVELOPMENT OF A GIS‐BASED FLOOD INFORMATION SYSTEM FOR FLOODPLAIN MODELING AND DAMAGE CALCULATION1
Authors: Yang C. R. , Tsai C. T.
Published: June 2007

ABSTRACT: This work presents a flexible system called GIS‐based Flood Information System (GFIS) for floodplain modeling, flood damages calculation, and flood information support. It includes two major components, namely floodplain modeling and custom designed modules. Model parameters and input data are gathered, reviewed, and compiled using custom designed modules. Through these modules, it is possible for GFIS to control the process of flood‐plain modeling, presentation of simulation results, and calculation of flood damages. Empirical stage‐damage curves are used to calculate the flood damages. These curves were generated from stage‐damage surveys of anthropogenic structures, crops, etc., in the coastal region of a frequently flooded area in Chia‐I County, Taiwan. The average annual flood damages are calculated with exceedance probability and flood damages for the designed rainfalls of 2, 5, 10, 25, 50, 100, and 200 year recurrence intervals with a duration of 24 hours. The average annual flood depth in this study area can also be calculated using the same method. The primary advantages of GFIS are its ability to accurately predict the locations of flood area, depth, and duration; calculate flood damages in the floodplain; and compare the reduction of flood damages for flood mitigation plans.
ARTIFICIAL NEURAL NETWORKS FOR SUBSURFACE DRAINAGE AND SUBIRRIGATION SYSTEMS IN ONTARIO, CANADA1
Authors: Yang Chun‐Chieh , Tan Chin S. , Prasher Shiv O.
Published: June 2007

ABSTRACT: Artificial neural network (ANN) models were developed to simulate fluctuations in midspan water table depths (WTD) given rainfall, potential evapotranspiration, and irrigation inputs on a Brookston clay loam in Woodslee, Ontario, having a dual‐purpose subsurface drainage/subirrigation setup. Water table depths and meteorologic data collected at this site from 1992 to 1994 and from 1996 to 1997 were used to train the ANNs. The ANNs were then used for real‐time control and time series simulations. The lowest root mean squared errors (RMSE) for the various ANNs were 60.6 mm for real‐time control simulation, and 88.4 mm for time‐series simulation of water table depths. It was possible to simulate WTD for the different modes of water table management in one network by incorporating an indicator for switching from one to the other. The ANN simulations were quite good even though the training data sets had irregular measurement intervals. With fewer input parameters and small network structures, ANNs still provided accurate results and required little time for training and execution. ANNs are therefore easier and faster to develop and run than conventional models and can contribute to the proper management of subsurface drainage and subirrigation systems.
SALMONID SMOLT SURVIVAL RELATIVE TO TURBINE EFFICIENCY AND ENTRAINMENT DEPTH IN HYDROELECTRIC POWER GENERATION1
Authors: Mathur Dilip , Heisey Paul G. , Skalski John R. , Kenney Daniel R.
Published: June 2007

ABSTRACT: The hypotheses that fish survival probabilities may be lower (1) at less than peak operating turbine efficiency; (2) at deeper entrainment depth; and (3) with the deployment of extended‐length intake guidance screens, are not supported by results on yearling chinook salmon smolts (Oncorhynchus tshawytscha) at Lower Granite Dam, Snake River, Washington. Estimated 96 h survival probabilities for the six test conditions ranged from 0.937 to 0.972, with the highest survival at turbine operating towards the lower end of its efficiency. A blanket recommendation to operate all Kaplan type turbines within ± 1 percent of their peak efficiency appears too restrictive. Cavitation mode survival (0.946) was comparable to that at peak operating efficiency mode (0.937), as was the survival between upper (0.947) and mid depths (0.937). Survival differed only slightly among three turbine intake bays at the same depth (0.937 to 0.954), most likely due to differential flow distribution. Extended‐length intake fish guidance screens did not reduce survival. However, the sources of injury somewhat differed with depth; probable pressure and shear‐related injuries were common on fish entrained at mid‐depth, and mechanically‐induced injuries were common at upper depth. Operating conditions that reduce turbulence within the turbine environment may enhance fish survival; however, controlled experiments that integrate turbine flow physics and geometry and the path entrained fish traverse are needed to develop specific guidance to further enhance fish passage survival.
ESTIMATING AVERAGE MONTHLY LAKE EVAPORATION IN THE NORTHEAST UNITED STATES1
Authors: Fennessey Neil M.
Published: June 2007

ABSTRACT: A methodology to estimate the average monthly lake evaporation, E(τ), (month τ=1,12) for fresh water bodies located in the northeast United States is presented. The approach combines analysis of at‐site, lake‐specific vertical water temperature profile data and a previously developed regional air temperature based model approximation of the widely accepted modified Penman energy budget estimate of mean monthly potential evaporation, Ep(τ) (mm/day). The paper presents procedures to develop site‐specific estimates of Ep(τ) and to convert water temperature data to average monthly conductive heat flux, G(τ). With monthly estimates of G(τ), the average monthly potential evaporation, Ep(τ), is then convertible to estimates of the average monthly lake evaporation, E(τ). This new method permits a good estimate of site‐specific lake evaporation rates without the data and computational requirements of the Penman energy budget procedure nor the comparatively expensive, time consuming field eddy correlation approach.
NUTRIENT CONCENTRATIONS AND YIELDS IN UNDEVELOPED STREAM BASINS OF THE UNITED STATES1
Authors: Clark Gregory M. , Mueller David K. , Mast M. Alisa
Published: June 2007

ABSTRACT:Data from 85 sites across the United States were used to estimate concentrations and yields of selected nutrients in streams draining relatively undeveloped basins. Flow‐weighted concentrations during 1990–1995 were generally low with median basin concentrations of 0.020, 0.087, 0.26, 0.010, and 0.022 milligrams per liter (mg/L) for ammonia as N, nitrate as N, total nitrogen, orthophosphate as P, and total phosphorus, respectively. The flow‐weighted concentration of nitrate exceeded 0.6 mg/L in only three basins. Total nitrogen exceeded 1 mg/L in only four basins, and total phosphorus exceeded 0.1 mg/L in only four basins. The median annual basin yield of ammonia as N, nitrate as N, total nitrogen, orthophosphate as P, and total phosphorus was 8.1, 26, 86, 2.8, and 8.5 kilograms per square kilometer, respectively. Concentrations and yields of nitrate tended to be highest in northeastern and mid‐Atlantic coastal states and correlated well with areas of high atmospheric nitrogen deposition. Concentrations and yields of total nitrogen were highest in the southeastern part of the nation and in parts of the upper Midwest. In the northeast, nitrate was generally the predominant form of nitrogen, and in the southeast and parts of the upper Midwest, organic nitrogen was the dominant form. Concentrations of total phosphorus were generally highest in the Rocky Mountain and Central Plain states.
REMOTE MONITORING OF SELECTED GROUND‐WATER DOMINATED LAKES IN THE NEBRASKA SAND HILLS1
Authors: Gosselin David C. , Rundquist Donald C. , McFeeters Stuart K.
Published: June 2007

ABSTRACT: The Landsat‐Muitispectral Scanner (MSS) data were used to measure lake area fluctuations (1972–1989) for 130 ground‐water dominated lakes in the Western Lakes Region of the Nebraska Sand Hills. In general, the pattern shown in lake area hydrographs was similar to that for in‐situ lake elevations. In‐situ lake‐elevation data verify that remote monitoring of surface‐area fluctuations, even at relatively coarse spatial resolution, is not only practical and useful, but also it elucidates the hydrologic characteristics of groundwater‐dominated lakes of the Sand Hills. The apparent differences in behavior between lakes in the northern and southern portions of the study area may be related to both their location in the regional ground water system and the substantial local hydrologic complexity.
EXPORT COEFFICIENT MODELING TO ASSESS PHOSPHORUS LOADING IN AN URBAN WATERSHED1
Authors: Winter Jennifer G. , Duthie Hamish C.
Published: June 2007

ABSTRACT: An export coefficient modeling approach was used to assess the influence of land use on phosphorus loading to a Southern Ontario stream. A model was constructed for the 1995–1996 water year and calibrated within ± 3 percent of the observed mean concentration of total phosphorus. It was found that runoff from urban areas contributed most to the loading of phosphorus to the stream. When the model was assessed by running it for the 1977–1978 water year, using water quality and land use data collected independently, agreement within ± 7 percent was obtained. The model was then used to forecast the impact of future urban development proposed for the watershed, in terms of phosphorus loading, and to evaluate the reduction in loading resulting from several urban best management practices (BMP). It was determined that phosphorus removal will have to be applied to all the urban runoff from the watershed to appreciably reduce stream phosphorus concentration. Of the BMP designs assessed, an infiltration pond system resulted in the greatest phosphorus load reduction, 50 percent from the 1995–1996 baseline.