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        1 2     

  Subjects -> WATER RESOURCES (Total: 132 journals)
Acta Limnologica Brasiliensia     Open Access   (Followers: 1)
Advances in Oceanography and Limnology     Partially Free   (Followers: 10)
Advances in Water Resource and Protection     Open Access   (Followers: 3)
Advances in Water Resources     Hybrid Journal   (Followers: 20)
African Journal of Aquatic Science     Hybrid Journal   (Followers: 13)
Agricultural Water Management     Hybrid Journal   (Followers: 16)
American Journal of Water Resources     Open Access   (Followers: 1)
American Water Works Association     Full-text available via subscription   (Followers: 15)
Anales de Hidrología Médica     Open Access  
Annals of Warsaw University of Life Sciences - SGGW. Land Reclamation     Open Access   (Followers: 2)
Annual Review of Marine Science     Full-text available via subscription   (Followers: 9)
Applied Water Science     Open Access   (Followers: 6)
Aquacultural Engineering     Hybrid Journal   (Followers: 7)
Aquaculture     Hybrid Journal   (Followers: 32)
Aquaculture Research     Hybrid Journal   (Followers: 26)
Aquatic Conservation Marine and Freshwater Ecosystems     Hybrid Journal   (Followers: 21)
Aquatic Geochemistry     Hybrid Journal   (Followers: 1)
Aquatic Living Resources     Hybrid Journal   (Followers: 11)
Aquatic Procedia     Open Access  
Aquatic Science and Technology     Open Access   (Followers: 1)
Aquatic Sciences     Hybrid Journal   (Followers: 11)
Asian Journal of Earth Sciences     Open Access   (Followers: 17)
Asian Journal of Rural Development     Open Access   (Followers: 9)
Australian Journal of Water Resources     Full-text available via subscription   (Followers: 6)
Bubble Science, Engineering & Technology     Hybrid Journal  
Canadian Water Resources Journal     Hybrid Journal   (Followers: 20)
Civil and Environmental Research     Open Access   (Followers: 12)
CLEAN - Soil, Air, Water     Hybrid Journal   (Followers: 16)
Computational Water, Energy, and Environmental Engineering     Open Access   (Followers: 2)
Cost Effectiveness and Resource Allocation     Open Access   (Followers: 3)
Desalination     Hybrid Journal   (Followers: 11)
Desalination and Water Treatment     Hybrid Journal   (Followers: 10)
Developments in Water Science     Full-text available via subscription   (Followers: 7)
Ecological Chemistry and Engineering S     Open Access   (Followers: 2)
Environmental Toxicology     Hybrid Journal   (Followers: 9)
EQA - International Journal of Environmental Quality     Open Access   (Followers: 1)
European journal of water quality - Journal européen d'hydrologie     Full-text available via subscription   (Followers: 5)
Ground Water Monitoring & Remediation     Hybrid Journal   (Followers: 11)
Grundwasser     Hybrid Journal  
Human Resources for Health     Open Access   (Followers: 4)
Hydro Nepal : Journal of Water, Energy and Environment     Open Access   (Followers: 1)
Hydrology Research     Partially Free   (Followers: 6)
Hydrology: Current Research     Open Access   (Followers: 10)
International Journal of Climatology     Hybrid Journal   (Followers: 13)
International Journal of Hydrology Science and Technology     Hybrid Journal   (Followers: 4)
International Journal of Nuclear Desalination     Hybrid Journal   (Followers: 2)
International Journal of River Basin Management     Hybrid Journal   (Followers: 1)
International Journal of Salt Lake Research     Hybrid Journal   (Followers: 2)
International Journal of Waste Resources     Open Access   (Followers: 5)
International Journal of Water     Hybrid Journal   (Followers: 11)
International Journal of Water Resources and Environmental Engineering     Open Access   (Followers: 1)
International Journal of Water Resources Development     Hybrid Journal   (Followers: 15)
Irrigation and Drainage     Hybrid Journal   (Followers: 3)
Irrigation Science     Hybrid Journal   (Followers: 3)
Journal of Aquatic Sciences     Full-text available via subscription  
Journal of Contemporary Water Resource & Education     Hybrid Journal   (Followers: 2)
Journal of Environmental Health Science & Engineering     Open Access   (Followers: 1)
Journal of Fisheries and Aquatic Science     Open Access   (Followers: 4)
Journal of Geophysical Research : Oceans     Partially Free   (Followers: 16)
Journal of Hydro-environment Research     Full-text available via subscription   (Followers: 6)
Journal of Hydroinformatics     Full-text available via subscription   (Followers: 1)
Journal of Hydrology (New Zealand)     Full-text available via subscription   (Followers: 1)
Journal of Hydrology and Hydromechanics     Open Access  
Journal of Hydrometeorology     Full-text available via subscription   (Followers: 3)
Journal of Limnology     Open Access   (Followers: 6)
Journal of the American Water Resources Association     Hybrid Journal   (Followers: 18)
Journal of Water and Climate Change     Partially Free   (Followers: 26)
Journal of Water and Health     Partially Free   (Followers: 1)
Journal of Water Chemistry and Technology     Hybrid Journal   (Followers: 7)
Journal of Water Resource and Hydraulic Engineering     Open Access   (Followers: 3)
Journal of Water Resource and Protection     Open Access   (Followers: 5)
Journal of Water Resource Engineering and Management     Full-text available via subscription  
Journal of Water Resources Planning and Management     Full-text available via subscription   (Followers: 22)
Journal of Water Reuse and Desalination     Partially Free   (Followers: 6)
Journal of Water Supply : Research and Technology - Aqua     Partially Free   (Followers: 9)
Journal of Water, Sanitation and Hygiene for Development     Open Access   (Followers: 3)
La Houille Blanche     Full-text available via subscription   (Followers: 1)
Lake and Reservoir Management     Hybrid Journal   (Followers: 4)
Lakes & Reservoirs Research & Management     Hybrid Journal   (Followers: 15)
Large Marine Ecosystems     Full-text available via subscription   (Followers: 1)
Mangroves and Salt Marshes     Hybrid Journal   (Followers: 3)
Marine and Freshwater Behaviour and Physiology     Hybrid Journal   (Followers: 2)
Methods in Oceanography : An International Journal     Hybrid Journal   (Followers: 2)
Michigan Journal of Sustainability     Open Access  
New Zealand Journal of Marine and Freshwater Research     Hybrid Journal   (Followers: 4)
Open Journal of Modern Hydrology     Open Access   (Followers: 1)
Osterreichische Wasser- und Abfallwirtschaft     Hybrid Journal  
Ozone Science & Engineering     Hybrid Journal   (Followers: 1)
Paddy and Water Environment     Hybrid Journal   (Followers: 1)
Research Journal of Environmental Toxicology     Open Access   (Followers: 2)
Reviews in Aquaculture     Hybrid Journal   (Followers: 10)
Revue des sciences de l'eau / Journal of Water Science     Full-text available via subscription   (Followers: 1)
Riparian Ecology and Conservation     Open Access   (Followers: 3)
River Research and Applications     Hybrid Journal   (Followers: 5)
River Systems     Full-text available via subscription   (Followers: 3)
SA Irrigation = SA Besproeiing     Full-text available via subscription  
San Francisco Estuary and Watershed Science     Open Access   (Followers: 1)
Sciences Eaux & Territoires : la Revue du Cemagref     Open Access   (Followers: 1)
Scientia Marina     Open Access   (Followers: 2)
Society & Natural Resources: An International Journal     Hybrid Journal   (Followers: 12)

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Journal Cover Journal of the American Water Resources Association
   [20 followers]  Follow    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
     ISSN (Print) 1093-474X - ISSN (Online) 1752-1688
     Published by John Wiley and Sons Homepage  [1603 journals]   [SJR: 0.817]   [H-I: 56]
  • Using Public Participation Geographic Information Systems to Identify
           Places of Watershed Service Provisioning
    • Authors: Cody Cox; Wayde Morse, Christopher Anderson, Luke Marzen
      Pages: n/a - n/a
      Abstract: In this study, we used public participation geographic information systems methods to collect spatial data identifying places that stakeholders in Mobile Bay, Alabama think are important providers of watershed services. These methods allowed us to spatially analyze participatory data from general public respondents and directly compare them with other scientific data in a geographic information systems database. This study identified which places in the region participants believe are important providers of specific watershed services, including fish nurseries, storm protection, flood protection, and water quality protection, which would likely have public support for conservation. Additionally, we assessed the accuracy of participant watershed service identification using land cover data to identify inconsistencies and participant knowledge gaps. This information can be used to target outreach education efforts. We found that the accuracy with which participants correctly identified places with the necessary land cover to provide each service varied considerably. We believe this to be a useful tool for managers to elicit stakeholder input and to identify knowledge gaps regarding the provisioning of watershed services.
      PubDate: 2014-12-16T10:34:35.114382-05:
      DOI: 10.1111/jawr.12269
       
  • Erratum
    • Authors: Gene J.‐Y. You; Ximing Cai
      Pages: n/a - n/a
      PubDate: 2014-12-11T05:51:11.203213-05:
      DOI: 10.1111/jawr.12274
       
  • Characterizing Geomorphic Change from Anthropogenic Disturbances to Inform
           Restoration in the Upper Cache River, Illinois
    • Authors: Kristen L. Bouska; Timothy J. Stoebner
      Pages: n/a - n/a
      Abstract: Over the past century, channelization, agricultural tiling, and land use changes have resulted in significant stream channel degradation of the Cache River in southern Illinois. With the increasing interest in restoration of the watershed's bottomland forests and swamps, we sought to characterize geomorphic change over the past 110 years to inform restoration and management. A previously surveyed stretch of river was resurveyed in the fall of 2011, following a record flood in the spring of that year. Results suggest that the slope of the channel in this section of the river has increased 345% between 1903 and 1972 (p 
      PubDate: 2014-12-08T23:34:48.035087-05:
      DOI: 10.1111/jawr.12266
       
  • Boater Perceptions of Environmental Issues Affecting Lakes in Northern
           Wisconsin
    • Authors: Ben Beardmore
      Pages: n/a - n/a
      Abstract: Understanding public perceptions of the importance of environmental issues is crucial for gauging support for management activities. I present a novel methodological approach to assess the importance boaters placed on 16 water issues in a lake‐rich region of northern Wisconsin. A latent class maximum difference conjoint model was used to examine the relationships between environmental concern and engagement with lake resources. Boaters were grouped to maximize observed heterogeneity in prioritizing issues of concern. Socio‐demographic characteristics, recreation specialization, place attachment, and attitudes concerning aquatic stewardship and invasive species management were then used to predict class membership. This modeling approach identified five groups whose perceptions of issues pertaining to lakes are influenced by their interactions with the lake environment. While anglers were most concerned about fishing quality, sightseers identified lakeshore development and loss of natural habitat. Groups also differed in their socio‐demographic and attitudinal characteristics. The priorities of each group were substantially different from those of the overall sample. Accounting for differences in stakeholders' environmental concerns may improve public involvement in water management initiatives by allowing managers to identify common concerns and prioritize important issues among multiple groups.
      PubDate: 2014-12-08T23:34:37.125132-05:
      DOI: 10.1111/jawr.12265
       
  • Variable Irrigation District Action in Water Trading
    • Authors: Narishwar Ghimire; Ronald C. Griffin
      Pages: n/a - n/a
      Abstract: Irrigation districts (IDs) in the American west are highly diverse in their economic attributes and local water scarcity circumstances. This diversity may affect reallocative action via water transactions as scarcity rises. The institutional background defining and constraining IDs is described here. For a Texas study region the progress of permanent water right transfers involving IDs is documented and examined. An econometric analysis of multiple decades of ID water transfer activities in the Lower Rio Grande Valley finds that IDs with larger initial water right holdings and higher populations in nearby cities are more likely to participate in agricultural‐to‐municipal water transfer activities. The findings suggest that consolidation of smaller water right holding IDs may be an avenue for quickening the pace of reallocation, especially in more populated areas.
      PubDate: 2014-12-08T23:33:58.123924-05:
      DOI: 10.1111/jawr.12267
       
  • Seasonal and Regional Patterns in Performance for a Baltic Sea Drainage
           Basin Hydrologic Model
    • Authors: Steve W. Lyon; Roya Meidani, Ype Velde, Helen E. Dahlke, Dennis P. Swaney, Carl‐Magnus Mörth, Christoph Humborg
      Pages: n/a - n/a
      Abstract: This study evaluates the ability of the Catchment SIMulation (CSIM) hydrologic model to describe seasonal and regional variations in river discharge over the entire Baltic Sea drainage basin (BSDB) based on 31 years of monthly simulation from 1970 through 2000. To date, the model has been successfully applied to simulate annual fluxes of water from the catchments draining into the Baltic Sea. Here, we consider spatiotemporal bias in the distribution of monthly modeling errors across the BSDB since it could potentially reduce the fidelity of predictions and negatively affect the design and implementation of land‐management strategies. Within the period considered, the CSIM model accurately reproduced the annual flows across the BSDB; however, it tended to underpredict the proportion of discharge during high‐flow periods (i.e., spring months) and overpredict during the summer low flow periods. While the general overpredictions during summer periods are spread across all the subbasins of the BSDB, the underprediction during spring periods is seen largely in the northern regions. By implementing a genetic algorithm calibration procedure and/or seasonal parameterization of subsurface water flows for a subset of the catchments modeled, we demonstrate that it is possible to improve the model performance albeit at the cost of increased parameterization and potential loss of parsimony.
      PubDate: 2014-12-08T23:33:51.317057-05:
      DOI: 10.1111/jawr.12268
       
  • Discussion
    • Authors: Francesco D'Asaro; Giovanni Grillone
      Pages: n/a - n/a
      Abstract: Epps et al. (2013) derived Curve Number (CN) values for two forested headwater watersheds in the Lower Coastal Plain of South Carolina during the 2008‐2011 period from rainfall‐runoff data, resulting in 23 events for the Upper Debidue Creek (UDC) watershed and in 20 events for Watershed 80 (WS80). D'Asaro and Grillone analyzed the P, CN data of the UDC watershed finding an evident “complacent” behavior, characterized by a declining CN with increasing P but without approaching a stable value at large storms. In this case, the traditional runoff CN equation does not fit well with the rainfall‐runoff data that indicate a partial source area watershed behavior and are more aptly modeled by the equation introduced by D'Asaro and Grillone (2012), who introduced a C parameter in the well‐known runoff CN formula. The C value, that represents the source area (fraction of drainage area) of the basin that produces runoff with a fixed CN 
      PubDate: 2014-12-08T23:31:20.553972-05:
      DOI: 10.1111/jawr.12264
       
  • A Modeling System to Assess Land Cover Land Use Change Effects on SAV
           Habitat in the Mobile Bay Estuary
    • Authors: Maurice G. Estes; Mohammad Z. Al‐Hamdan, Jean T. Ellis, Chaeli Judd, Dana Woodruff, Ronald M. Thom, Dale Quattrochi, Brian Watson, Hugo Rodriguez, Hoyt Johnson, Tom Herder
      Pages: n/a - n/a
      Abstract: Estuarine ecosystems are largely influenced by watersheds directly connected to them. In the Mobile Bay, Alabama watersheds we examined the effect of land cover and land use (LCLU) changes on discharge rate, water properties, and submerged aquatic vegetation, including freshwater macrophytes and seagrasses, throughout the estuary. LCLU scenarios from 1948, 1992, 2001, and 2030 were used to influence watershed and hydrodynamic models and evaluate the impact of LCLU change on shallow aquatic ecosystems. Overall, our modeling results found that LCLU changes increased freshwater flows into Mobile Bay altering temperature, salinity, and total suspended sediments (TSS). Increased urban land uses coupled with decreased agricultural/pasture lands reduced TSS in the water column. However, increased urbanization or agricultural/pasture land coupled with decreased forest land resulted in higher TSS concentrations. Higher sediment loads were usually strongly correlated with higher TSS levels, except in areas where a large extent of wetlands retained sediment discharged during rainfall events. The modeling results indicated improved water clarity in the shallow aquatic regions of Mississippi Sound and degraded water clarity in the Wolf Bay estuary. This integrated modeling approach will provide new knowledge and tools for coastal resource managers to manage shallow aquatic habitats that provide critical ecosystem services.
      PubDate: 2014-11-11T04:54:24.910606-05:
      DOI: 10.1111/jawr.12263
       
  • Development and Operational Testing of a Super‐Ensemble Artificial
           Intelligence Flood‐Forecast Model for a Pacific Northwest River
    • Authors: Sean W. Fleming; Dominique R. Bourdin, Dave Campbell, Roland B. Stull, Tobi Gardner
      Pages: n/a - n/a
      Abstract: Coastal catchments in British Columbia, Canada, experience a complex mixture of rainfall‐ and snowmelt‐driven contributions to flood events. Few operational flood‐forecast models are available in the region. Here, we integrated a number of proven technologies in a novel way to produce a super‐ensemble forecast system for the Englishman River, a flood‐prone stream on Vancouver Island. This three‐day‐ahead modeling system utilizes up to 42 numerical weather prediction model outputs from the North American Ensemble Forecast System, combined with six artificial neural network‐based streamflow models representing various slightly different system conceptualizations, all of which were trained exclusively on historical high‐flow data. As such, the system combines relatively low model development times and costs with the generation of fully probabilistic forecasts reflecting uncertainty in the simulation of both atmospheric and terrestrial hydrologic dynamics. Results from operational testing by British Columbia's flood forecasting agency during the 2013‐2014 storm season suggest that the prediction system is operationally useful and robust.
      PubDate: 2014-11-11T04:54:14.18727-05:0
      DOI: 10.1111/jawr.12259
       
  • Associations between Water Physicochemistry and Prymnesium parvum
           Presence, Abundance, and Toxicity in West Texas Reservoirs
    • Authors: Matthew M. VanLandeghem; Mukhtar Farooqi, Greg M. Southard, Reynaldo Patiño
      Pages: n/a - n/a
      Abstract: Toxic blooms of golden alga (Prymnesium parvum) have caused substantial ecological and economic harm in freshwater and marine systems throughout the world. In North America, toxic blooms have impacted freshwater systems including large reservoirs. Management of water chemistry is one proposed option for golden alga control in these systems. The main objective of this study was to assess physicochemical characteristics of water that influence golden alga presence, abundance, and toxicity in the Upper Colorado River basin (UCR) in Texas. The UCR contains reservoirs that have experienced repeated blooms and other reservoirs where golden alga is present but has not been toxic. We quantified golden alga abundance (hemocytometer counts), ichthyotoxicity (bioassay), and water chemistry (surface grab samples) at three impacted reservoirs on the Colorado River; two reference reservoirs on the Concho River; and three sites at the confluence of these rivers. Sampling occurred monthly from January 2010 to July 2011. Impacted sites were characterized by higher specific conductance, calcium and magnesium hardness, and fluoride than reference and confluence sites. At impacted sites, golden alga abundance and toxicity were positively associated with salinity‐related variables and blooms peaked at ~10°C and generally did not occur above 20°C. Overall, these findings suggest management of land and water use to reduce hardness or salinity could produce unfavorable conditions for golden alga.
      PubDate: 2014-11-11T04:54:09.825794-05:
      DOI: 10.1111/jawr.12262
       
  • Spatiotemporal Associations of Reservoir Nutrient Characteristics and the
           Invasive, Harmful Alga Prymnesium parvum in West Texas
    • Authors: Matthew M. VanLandeghem; Mukhtar Farooqi, Greg M. Southard, Reynaldo Patiño
      Pages: n/a - n/a
      Abstract: Golden alga (Prymnesium parvum) is a harmful alga that has caused ecological and economic harm in freshwater and marine systems worldwide. In inland systems of North America, toxic blooms have nearly eliminated fish populations in some systems. Modifying nutrient profiles through alterations to land or water use may be a viable alternative for golden alga control in reservoirs. The main objective of this study was to improve our understanding of the nutrient dynamics that influence golden alga bloom formation and toxicity in west Texas reservoirs. We examined eight sites in the Upper Colorado River basin, Texas: three impacted reservoirs that have experienced repeated golden alga blooms; two reference reservoirs where golden alga is present but nontoxic; and three confluence sites downstream of the impacted and reference sites. Total, inorganic, and organic nitrogen and phosphorus and their ratios were quantified monthly along with golden alga abundance and ichthyotoxicity between December 2010 and July 2011. Blooms persisted for several months at the impacted sites, which were characterized by high organic nitrogen and low inorganic nitrogen. At impacted sites, abundance was positively associated with inorganic phosphorus and bloom termination coincided with increases in inorganic nitrogen and decreases in inorganic phosphorus in late spring. Management of both inorganic and organic forms of nutrients may create conditions in reservoirs unfavorable to golden alga.
      PubDate: 2014-11-11T04:54:04.768774-05:
      DOI: 10.1111/jawr.12261
       
  • Discussion
    • Authors: Steven E. Pells; William L. Peirson
      Pages: n/a - n/a
      PubDate: 2014-11-11T04:53:56.595319-05:
      DOI: 10.1111/jawr.12260
       
  • Reply to Discussion
    • Authors: Hilda Kwan; Sherman Swanson
      Pages: n/a - n/a
      PubDate: 2014-10-27T08:31:09.675613-05:
      DOI: 10.1111/jawr.12257
       
  • Discussion
    • Authors: David L. Rosgen
      Pages: n/a - n/a
      PubDate: 2014-10-27T08:31:04.424568-05:
      DOI: 10.1111/jawr.12258
       
  • Resolution and Analysis of Spatial Variations and Patterns in an Urban
           Lake with Rapid Profiling Instrumentation
    • Authors: Anthony R. Prestigiacomo; Steven W. Effler, David A. Matthews
      Pages: n/a - n/a
      Abstract: Rapid response vertical profiling instrumentation was used to document spatial variability and patterns in a small urban lake, Onondaga Lake, associated with multiple drivers. Paired profiles of temperature, specific conductance (SC), turbidity (Tn), fluorometric chlorophyll a (Chlf), and nitrate nitrogen (NO3−) were collected at >30 fixed locations (a “gridding”) weekly, over the spring to fall interval of several years. These gridding data are analyzed (1) to characterize phytoplankton (Chlf) patchiness in the lake's upper waters, (2) to establish the representativeness of a single long‐term site for monitoring lake‐wide conditions, and (3) to resolve spatial patterns of multiple tracers imparted by buoyancy effects of inflows. Multiple buoyancy signatures were resolved, including overflows from less dense inflows, and interflows to metalimnetic depths and underflows to the bottom from the plunging of more dense inputs. Three different metrics had utility as tracers in depicting the buoyancy signatures as follows: (1) SC, for salinity‐enriched tributaries and the more dilute river that receives the lake's outflow, (2) Tn, for the tributaries during runoff events, and (3) NO3−, for the effluent of a domestic waste treatment facility and from the addition of NO3− solution to control methyl mercury. The plunging inflow phenomenon, which frequently prevailed, has important management implications.
      PubDate: 2014-10-18T05:10:40.911642-05:
      DOI: 10.1111/jawr.12243
       
  • Hydrologic Sensitivity to Climate and Land Use Changes in the Santiam
           River Basin, Oregon
    • Authors: Cristina Mateus; Desiree D. Tullos, Christopher G. Surfleet
      Pages: n/a - n/a
      Abstract: Future changes in water supply are likely to vary across catchments due to a river basin's sensitivity to climate and land use changes. In the Santiam River Basin (SRB), Oregon, we examined the role elevation, intensity of water demands, and apparent intensity of groundwater interactions, as characteristics that influence sensitivity to climate and land use changes, on the future availability of water resources. In the context of water scarcity, we compared the relative impacts of changes in water supply resulting from climate and land use changes to the impacts of spatially distributed but steady water demand. Results highlight how seasonal runoff responses to climate and land use changes vary across subbasins with differences in hydrogeology, land use, and elevation. Across the entire SRB, water demand exerts the strongest influence on basin sensitivity to water scarcity, regardless of hydrogeology, with the highest demand located in the lower reaches dominated by agricultural and urban land uses. Results also indicate that our catchment with mixed rain‐snow hydrology and with mixed surface‐groundwater may be more sensitive to climate and land use changes, relative to the catchment with snowmelt‐dominated runoff and substantial groundwater interactions. Results highlight the importance of evaluating basin sensitivity to change in planning for planning water resources storage and allocation across basins in variable hydrogeologic settings.
      PubDate: 2014-10-16T15:09:01.082011-05:
      DOI: 10.1111/jawr.12256
       
  • Evaluating Alternative Temporal Survey Designs for Monitoring Wetland Area
           and Detecting Changes over Time in California
    • Authors: Leila G. Lackey; Eric D. Stein
      Pages: n/a - n/a
      Abstract: Evaluation of wetland extent and changes in extent is a foundation of many wetland monitoring and assessment programs. Probabilistic sampling and mapping provides a cost‐effective alternative to comprehensive mapping for large geographic areas. One unresolved challenge for probabilistic or design‐based approaches is how best to monitor both status (e.g., extent at a single point in time) and trends (e.g., changes in extent over time) within a single monitoring program. Existing wetland status and trends (S&T) monitoring programs employ fixed sampling locations; however, theoretical evaluation and limited implementation in other landscape monitoring areas suggest that alternative designs could increase statistical efficiency and overall accuracy. In particular, designs that employ both fixed and nonfixed sampling locations (alternately termed permanent and temporary samples), termed sampling with partial replacement (SPR), are considered to efficiently and effectively balance monitoring current status with detection of trends. This study utilized simulated sampling to assess the performance of fixed sampling locations, SPR, and strictly nonfixed designs for monitoring wetland S&T over time. Modeled changes in wetland density over time were used as inputs for sampling simulations. In contrast to previous evaluations of SPR, the results of this study support the use of a fixed sampling design and show that SPR may underestimate both S&T.
      PubDate: 2014-10-16T15:08:44.445196-05:
      DOI: 10.1111/jawr.12254
       
  • Model‐Based Nitrogen and Phosphorus (Nutrient) Criteria for Large
           Temperate Rivers: 2. Criteria Derivation
    • Authors: Michael W. Suplee; Kyle F. Flynn, Steven C. Chapra
      Pages: n/a - n/a
      Abstract: Nitrogen and phosphorus criteria were developed for 233 km of the Yellowstone River, one of the first cases where a mechanistic model has been used to derive large river numeric nutrient criteria. A water quality model and a companion model which simulates lateral algal biomass across transects were used to simulate effects of increasing nutrients on five variables (dissolved oxygen, total organic carbon, total dissolved gas, pH, and benthic algal biomass in depths ≤1 m). Incremental increases in nutrients were evaluated relative to their impact on predefined thresholds for each variable; the first variable to exceed a threshold set the nutrient criteria. Simulations were made at a low flow, the 14Q5 (lowest average 14 consecutive day flow, July‐September, recurring one in five years), which was derived using benthic algae growth curves and EPA guidance on excursion frequency. An extant climate dataset with an annual recurrence was used, and tributary water quality and flows were coincident with the river's 10 lowest flow years. The river had different sensitivities to nutrients longitudinally, pH being the most sensitive variable in the upstream reach and algal biomass in the lower. Model‐based criteria for the Yellowstone River are as follows: between the Bighorn and Powder river confluences, 55 μg TP/l and 655 μg TN/l; from the Powder River confluence to Montana state line, 95 μg TP/l and 815 μg TN/l. Pros and cons of using steady‐state models to derive river nutrient criteria are discussed.
      PubDate: 2014-10-16T15:08:35.015841-05:
      DOI: 10.1111/jawr.12252
       
  • Model‐Based Nitrogen and Phosphorus (Nutrient) Criteria for Large
           Temperate Rivers: 1. Model Development and Application
    • Authors: Kyle F. Flynn; Michael W. Suplee, Steven C. Chapra, Hua Tao
      Pages: n/a - n/a
      Abstract: An initial inquiry into model‐based numeric nitrogen and phosphorus (nutrient) criteria for large rivers is presented. Field data collection and associated modeling were conducted on a segment of the lower Yellowstone River in the northwestern United States to assess the feasibility of deriving numeric nutrient criteria using mechanistic water‐quality models. The steady‐state one‐dimensional model QUAL2K and a transect‐based companion model AT2K were calibrated and confirmed against low‐flow conditions at a time when river loadings, water column chemistry, and diurnal indicators were approximately steady state. Predictive simulation was then implemented via nutrient perturbation to evaluate the steady‐state and diurnal response of the river to incremental nutrient additions. In this first part of a two‐part series, we detail our modeling approach, model selection, calibration and confirmation, sensitivity analysis, model outcomes, and associated uncertainty. In the second part (Suplee et al., 2014) we describe the criteria development process using the tools described herein. Both articles provide a fundamental understanding of the process required to develop site‐specific numeric nutrient criteria using models in applied regulatory settings.
      PubDate: 2014-10-16T15:07:05.560474-05:
      DOI: 10.1111/jawr.12253
       
  • Can Rapid Assessment Protocols Be Used to Judge Sediment Impairment in
           Gravel‐Bed Streams? A Commentary
    • Authors: Thomas E. Lisle; John M. Buffington, Peter R. Wilcock, Kristin Bunte
      Pages: n/a - n/a
      Abstract: Land management agencies commonly use rapid assessments to evaluate the impairment of gravel‐bed streams by sediment inputs from anthropogenic sources. We question whether rapid assessment can be used to reliably judge sediment impairment at a site or in a region. Beyond the challenges of repeatable and accurate sampling, we argue that a single metric or protocol is unlikely to reveal causative relations because channel condition can result from multiple pathways, processes, and background controls. To address these concerns, a contextual analysis is needed to link affected resources, causal factors, and site history to reliably identify human influences. Contextual analysis is equivalent in principle to cumulative effects and watershed analyses and has a rich history, but has gradually been replaced by rapid assessment methods. Although the approaches differ, rapid assessment and contextual analysis are complementary and can be implemented in a two‐tiered approach in which rapid assessment provides a coarse (first‐tier) analysis to identify sites that deserve deeper contextual assessment (second‐tier). Contextual analysis is particularly appropriate for site‐specific studies that should be tailored to local conditions. A balance between rapid assessment and contextual analysis is needed to provide the most effective information for management decisions.
      PubDate: 2014-10-16T15:04:40.88187-05:0
      DOI: 10.1111/jawr.12255
       
  • Reducing Nitrogen Export from the Corn Belt to the Gulf of Mexico:
           Agricultural Strategies for Remediating Hypoxia
    • Authors: Eileen McLellan; Dale Robertson, Keith Schilling, Mark Tomer, Jill Kostel, Doug Smith, Kevin King
      Pages: n/a - n/a
      Abstract: SPAtially Referenced Regression on Watershed models developed for the Upper Midwest were used to help evaluate the nitrogen‐load reductions likely to be achieved by a variety of agricultural conservation practices in the Upper Mississippi‐Ohio River Basin (UMORB) and to compare these reductions to the 45% nitrogen‐load reduction proposed to remediate hypoxia in the Gulf of Mexico (GoM). Our results indicate that nitrogen‐management practices (improved fertilizer management and cover crops) fall short of achieving this goal, even if adopted on all cropland in the region. The goal of a 45% decrease in loads to the GoM can only be achieved through the coupling of nitrogen‐management practices with innovative nitrogen‐removal practices such as tile‐drainage treatment wetlands, drainage–ditch enhancements, stream‐channel restoration, and floodplain reconnection. Combining nitrogen‐management practices with nitrogen‐removal practices can dramatically reduce nutrient export from agricultural landscapes while minimizing impacts to agricultural production. With this approach, it may be possible to meet the 45% nutrient reduction goal while converting less than 1% of cropland in the UMORB to nitrogen‐removal practices. Conservationists, policy makers, and agricultural producers seeking a workable strategy to reduce nitrogen export from the Corn Belt will need to consider a combination of nitrogen‐management practices at the field scale and diverse nitrogen‐removal practices at the landscape scale.
      PubDate: 2014-10-15T13:34:43.368097-05:
      DOI: 10.1111/jawr.12246
       
  • Prediction of Total Sediment Load in Sand‐Bed Rivers in Korea Using
           Lateral Distribution Method
    • Authors: Sung‐Uk Choi; Jinhwi Lee
      Pages: n/a - n/a
      Abstract: A new method for numerically predicting the total sediment load in a river is proposed. The method can be used to predict the total sediment load with information on channel geometry and slope, flow, and bed materials. The conventional method uses a 1D approach that assumes the channel has a wide rectangular shape. However, the proposed method computes depth‐averaged velocity over the width and predicts the total sediment load based on the flow computations. The new method, therefore, is expected to predict better if the flow changes significantly in the lateral direction. The proposed method was applied to three large sand‐bed rivers in Korea, where information is available regarding suspended sediment. Five formulas were tested of use in making total sediment load computations, namely Engelund‐Hansen's, Ackers‐White's, Yang's, Brownlie's, and Karim's formulas. The predicted total sediment loads are compared not only with measured data but also with results calculated using the 1D approach. Discrepancy ratios between the predicted and measured total sediment loads are given and the results are discussed.
      PubDate: 2014-10-15T13:32:17.582689-05:
      DOI: 10.1111/jawr.12249
       
  • A Spatially Explicit Model for Mapping Headwater Streams
    • Authors: Periann P. Russell; Susan M. Gale, Breda Muñoz, John R. Dorney, Matthew J. Rubino
      Pages: n/a - n/a
      Abstract: Headwater streams are the primary sources of water in a drainage network and serve as a critical hydrologic link between the surrounding landscape and larger, downstream surface waters. Many states, including North Carolina, regulate activity in and near headwater streams for the protection of water quality and aquatic resources. A fundamental tool for regulatory management is an accurate representation of streams on a map. Limited resources preclude field mapping every headwater stream and its origin across a large region. It is more practical to develop a model for headwater streams based on a sample of field data that can then be extrapolated to a larger area of interest. The North Carolina Division of Water Quality has developed a cost‐effective method for modeling and mapping the location, length, and flow classification (intermittent and perennial) of headwater streams. We used a multiple logistic regression approach that combined field data and terrain derivatives for watersheds located in the Triassic Basins ecoregion. Field data were collected using a standard methodology for identifying headwater streams and origins. Terrain derivatives were generated from digital elevation models interpolated from bare‐earth Light Detection and Range data. Model accuracies greater than 80% were achieved in classifying stream presence and absence, stream length and perennial stream length, but were not as consistent in predicting intermittent stream length.
      PubDate: 2014-10-15T13:31:02.932301-05:
      DOI: 10.1111/jawr.12250
       
  • Salinity as a Limiting Factor for Biological Condition in
           Mining‐Influenced Central Appalachian Headwater Streams
    • Authors: Anthony J. Timpano; Stephen H. Schoenholtz, David J. Soucek, Carl E. Zipper
      Pages: n/a - n/a
      Abstract: Recent studies have found that Appalachian coal mining causes increased surface water salinity, and that benthic macroinvertebrate communities in salinized mining‐influenced streams differ from communities in streams draining unmined areas. Understanding the role of salinity in shaping these communities is challenging because such streams are often influenced by a variety of stressors in addition to salinity. We characterized associations of salinity with biotic condition while isolating salinity from other stressors through rigorous site selection. We used a multimetric index of biotic condition to characterize benthic macroinvertebrate communities in headwater streams in the Central Appalachian Ecoregion of Virginia across a gradient of sulfate‐dominated salinity. We found strong negative seasonal correlations between biotic condition and three salinity measures (specific conductance, total dissolved solids, and SO42− concentration). We found no evidence to suggest stressors other than salinity as significant influences on biotic condition in these streams. Our results confirm negative associations of salinity with benthic macroinvertebrate community condition, as observed in other studies. Thus, our findings demonstrate that elevated salinity is an important limiting factor for biological condition in Central Appalachian headwater streams.
      PubDate: 2014-10-15T13:30:57.322944-05:
      DOI: 10.1111/jawr.12247
       
  • Describing Damage to Stream Modification Projects in Constrained Settings
    • Authors: Cidney J. Jones; Peggy A. Johnson
      Pages: n/a - n/a
      Abstract: Complex relationships between stream functions and processes make evaluation of stream modification projects difficult. Informed by vague objectives and minimal monitoring data, post‐construction project evaluations can often be a subjective attribution of success or failure. This article provides a simple framework to rapidly describe the degree of damage in stream modification projects performed in constrained settings. Based on widely accepted evaluations of physical habitat quality and stream stability, the damage states framework describes a continuum of damage in multiple categories that relate natural stream functions to the often desired state of static equilibrium. Given that channel form is closely related to stream function, it follows that changes to the channel form result in changes in function. The damage states focus on damage to flow hydraulics, sediment transport and channel equilibrium, hydraulic, and geomorphic parameters that describe basic stream functioning and support higher level functions in the modified channel. The damage states can be used in decision making as a systematic method to determine the need for repair and design adjustments.
      PubDate: 2014-10-15T13:30:43.474752-05:
      DOI: 10.1111/jawr.12248
       
  • Book Reviews
    • Authors: Seung Ah Byun
      Pages: n/a - n/a
      PubDate: 2014-10-15T13:30:38.572404-05:
      DOI: 10.1111/jawr.12251
       
  • Nitrogen Removal by Stormwater Management Structures: A Data Synthesis
    • Authors: Benjamin J. Koch; Catherine M. Febria, Muriel Gevrey, Lisa A. Wainger, Margaret A. Palmer
      Pages: n/a - n/a
      Abstract: A comprehensive synthesis of data from empirically based published studies and a widely used stormwater best management practice (BMP) database were used to assess the variability in nitrogen (N) removal performance of urban stormwater ponds, wetlands, and swales and to identify factors that may explain this variability. While the data suggest that BMPs were generally effective on average, removal efficiencies of ammonium (NH4), nitrate (NO3), and total nitrogen (TN) were highly variable ranging from negative (i.e., BMPs acting as sources of N) to 100%. For example, removal of NO3 varied from (median ±1 SD) −15 ± 49% for dry ponds, 32 ± 120% for wet ponds, 58 ± 210% for wetlands, and 37 ± 29% for swales. Across the same BMP types, TN removal was 27 ± 24%, 40 ± 31%, 61 ± 30%, and 50 ± 29%. NH4 removal was 9 ± 36%, 29 ± 72%, 31 ± 24%, and 45 ± 34%. BMP size, age, and location explained some of the variability. For example, small and shallow ponds and wetlands were more effective than larger, deeper ones in removing N. Despite well‐known intra‐annual variation in N fluxes, most measurements have been made over short time periods using concentrations, not flow‐weighted N fluxes. Urban N export is increasing in some areas as large storms become more frequent. Thus, accounting for the full range of BMP performance under such conditions is crucial. A select number of long‐term flux‐based BMP studies that rigorously measure rainfall, hydrology, and site conditions could improve BMP implementation.
      PubDate: 2014-09-03T09:03:23.812665-05:
      DOI: 10.1111/jawr.12223
       
  • Sustainable Rainwater Catchment Systems for Micronesian Atoll Communities
    • Authors: Corey D. Wallace; Ryan T. Bailey
      Pages: n/a - n/a
      Abstract: Atoll island communities rely on rainwater catchment systems (RWCS) as a primary method of storing freshwater. However, stored freshwater can be depleted during times of drought, requiring importation of water to sustain community living. To maintain adequate water supply under future climatic conditions, the functioning of RWCS for atoll communities must be analyzed and optimal designs must be adopted. In this study, a quantitative analysis of stored daily water volumes is provided for atoll islands within the Federated States of Micronesia (FSM), with Nikahlap Island, Pakein Atoll, and a generic island in western FSM used as representative cases. Using a daily water balance model for the RWCS, baseline conditions are simulated for the 1997‐1999 time period, during which an intense El Niño‐induced drought occurred, and a sensitivity analysis is performed to quantify the influence of RWCS features on water system outputs, whereupon an optimal RWCS design using existing infrastructure is analyzed. Results indicate the strong influence of catchment area, system efficiency, and storage capacity on water volumes and the depletion of water during dry seasons and drought periods using current RWCS infrastructure. Adequate storage can be maintained during a major drought if unused RWCS features are employed and if minimal rationing is adopted. Study results provide water resource managers and government officials with valuable data for consideration in water security measures.
      PubDate: 2014-09-03T09:02:47.978432-05:
      DOI: 10.1111/jawr.12244
       
  • Discussion
    • Authors: David L. Rosgen
      Pages: n/a - n/a
      PubDate: 2014-09-03T09:02:44.540777-05:
      DOI: 10.1111/jawr.12242
       
  • Reply to Discussion
    • Authors: Kristan Cockerill; William P. Anderson
      Pages: n/a - n/a
      PubDate: 2014-09-03T09:02:42.970719-05:
      DOI: 10.1111/jawr.12241
       
  • Pre‐Development Groundwater Conditions Surrounding Memphis,
           Tennessee: Controversy and Unexpected Outcomes
    • Authors: Brian Waldron; Daniel Larsen
      Pages: n/a - n/a
      Abstract: Reliance on groundwater resources by differing governing bodies can create transboundary disputes raising questions of ownership and apportionment as the resource becomes strained through overuse or threatened by contamination. Transboundary disputes exist at varying scales, from conflicts between countries to smaller disputes between intrastate jurisdictions. In 2005 within the United States, the State of Mississippi filed a lawsuit against its political neighbor and their utility, the City of Memphis and Memphis Light, Gas, and Water, for groundwater deemed owned by the State of Mississippi to be wrongfully diverted across the state line and into Tennessee by the defendants. The basis of the lawsuit was potentiometric maps of groundwater levels for the Memphis aquifer that showed under suggested pre‐development conditions no flow occurring across the Mississippi‐Tennessee state line, but subsequent historic potentiometric maps show a cone of depression under the City of Memphis with a clear northwesterly gradient from Mississippi into Tennessee. The suggested pre‐development conditions were derived from limited groundwater level observations between 41 and 74 years post‐development. A new pre‐development map is constructed using historic records that range 0‐17 years post‐development that shows the natural flow is northwesterly from Mississippi into Tennessee and transboundary groundwater quantities have actually decreased since pre‐development conditions.
      PubDate: 2014-09-03T09:02:40.765267-05:
      DOI: 10.1111/jawr.12240
       
  • Development of the Spatial Rainfall Generator (SRGEN) for the Agricultural
           Policy/Environmental Extender Model
    • Authors: Jaehak Jeong; Jimmy R. Williams, Colleen G. Rossi, Robin A. Taylor, Xiuying Wang, William E. Fox
      Pages: n/a - n/a
      Abstract: Accurate spatial representation of climatic patterns is often a challenge in modeling biophysical processes at the watershed scale, especially where the representation of a spatial gradient in rainfall is not sufficiently captured by the number of weather stations. The spatial rainfall generator (SRGEN) is developed as an extension of the “weather generator” (WXGEN), a component of the Agricultural Policy/Environmental eXtender (APEX) model. SRGEN generates spatially distributed daily rainfall using monthly weather statistics available at multiple locations in a watershed. The spatial rainfall generator as incorporated in APEX is tested on the Cowhouse watershed (1,178 km2) in central Texas. The watershed presented a significant spatial rainfall gradient of 2.9 mm/km in the lateral (north‐south) directions based on four rainfall gages. A comparative analysis between SRGEN and WXGEN indicates that SRGEN performs well (PBIAS = 2.40%). Good results were obtained from APEX for streamflow (NSE = 0.99, PBIAS = 8.34%) and NO3‐N and soluble P loads (PBIAS ≈ 6.00% for each, respectively). However, APEX underpredicted sediment yield and organic N and P loads (PBIAS: 24.75‐27.90%) with SRGEN, although its uncertainty in output was lower than WXGEN results (PBIAS: −13.02 to −46.13%). The overall improvement achieved in rainfall generation by SRGEN is demonstrated to be effective in the improving model performance on flow and water quality output.
      PubDate: 2014-09-03T09:02:34.388698-05:
      DOI: 10.1111/jawr.12239
       
  • The Aging of America's Reservoirs: In‐Reservoir and Downstream
           Physical Changes and Habitat Implications
    • Authors: Kyle E. Juracek
      Pages: n/a - n/a
      Abstract: Reservoirs are important for various purposes including flood control, water supply, power generation, and recreation. The aging of America's reservoirs and progressive loss of water storage capacity resulting from ongoing sedimentation, coupled with increasing societal needs, will cause the social, economic, environmental, and political importance of reservoirs to continually increase. The short‐ and medium‐term (50 years) environmental changes as reservoirs enter “old” age are less understood. Additional research is needed to help guide the future management of aging reservoir systems and support the difficult decisions that will have to be made. Important research directions include assessment of climate change effects on aging and determination of ecosystem response to ongoing aging and various management actions that may be taken with the intent of minimizing or reversing the physical effects of aging.
      PubDate: 2014-09-03T09:02:27.614565-05:
      DOI: 10.1111/jawr.12238
       
  • Erratum
    • Authors: Hilda Kwan; Sherman Swanson
      Pages: n/a - n/a
      PubDate: 2014-08-13T11:37:23.385245-05:
      DOI: 10.1111/jawr.12245
       
  • Trophic State in Voyageurs National Park Lakes before and after
           Implementation of a Revised Water‐Level Management Plan
    • Authors: Victoria G. Christensen; Ryan P. Maki
      Pages: n/a - n/a
      Abstract: We compiled Secchi depth, total phosphorus, and chlorophyll a (Chla) data from Voyageurs National Park lakes and compared datasets before and after a new water‐level management plan was implemented in January 2000. Average Secchi depth transparency improved (from 1.9 to 2.1 m, p = 0.020) between 1977‐1999 and 2000‐2011 in Kabetogama Lake for August samples only and remained unchanged in Rainy, Namakan, and Sand Point Lakes, and Black Bay in Rainy Lake. Average open‐water season Chla concentration decreased in Black Bay (from an average of 13 to 6.0 μg/l, p = 0.001) and Kabetogama Lake (from 9.9 to 6.2 μg/l, p = 0.006) between 1977‐1999 and 2000‐2011. Trophic state index decreased significantly in Black Bay from 59 to 51 (p = 0.006) and in Kabetogama Lake from 57 to 50 (p = 0.006) between 1977‐1999 and 2000‐2011. Trophic state indices based on Chla indicated that after 2000, Sand Point, Namakan, and Rainy Lakes remained oligotrophic, whereas eutrophication has decreased in Kabetogama Lake and Black Bay. Although nutrient inputs from inflows and internal sources are still sufficient to produce annual cyanobacterial blooms and may inhibit designated water uses, trophic state has decreased for Kabetogama Lake and Black Bay and there has been no decline in lake ecosystem health since the implementation of the revised water‐level management plan.
      PubDate: 2014-08-12T11:38:10.788168-05:
      DOI: 10.1111/jawr.12234
       
  • Modeling Long‐Term Trends of Chlorinated Ethene Contamination at a
           Public Supply Well
    • Authors: Francis H. Chapelle; Leon J. Kauffman, Mark A. Widdowson
      Pages: n/a - n/a
      Abstract: A mass‐balance solute‐transport modeling approach was used to investigate the effects of dense nonaqueous phase liquid (DNAPL) volume, composition, and generation of daughter products on simulated and measured long‐term trends of chlorinated ethene (CE) concentrations at a public supply well. The model was built by telescoping a calibrated regional three‐dimensional MODFLOW model to the capture zone of a public supply well that has a history of CE contamination. The local model was then used to simulate the interactions between naturally occurring organic carbon that acts as an electron donor, and dissolved oxygen (DO), CEs, ferric iron, and sulfate that act as electron acceptors using the Sequential Electron Acceptor Model in three dimensions (SEAM3D) code. The modeling results indicate that asymmetry between rapidly rising and more gradual falling concentration trends over time suggests a DNAPL rather than a dissolved source of CEs. Peak concentrations of CEs are proportional to the volume and composition of the DNAPL source. The persistence of contamination, which can vary from a few years to centuries, is proportional to DNAPL volume, but is unaffected by DNAPL composition. These results show that monitoring CE concentrations in raw water produced by impacted public supply wells over time can provide useful information concerning the nature of contaminant sources and the likely future persistence of contamination.
      PubDate: 2014-08-12T11:38:04.217703-05:
      DOI: 10.1111/jawr.12230
       
  • Specific Yield Functions for Estimating Evapotranspiration from Diurnal
           Surface Water Cycles
    • Authors: A. Jason Hill; Brandon Durchholz
      Pages: n/a - n/a
      Abstract: The White method has been routinely used to estimate evapotranspiration using diurnal variations in groundwater levels. Applications to surface water systems (e.g., wetlands) are less common. For applications to surface water systems, a stage‐dependent specific yield function must be defined. This is especially important for small wetlands formed in topographic depressions with bowl shaped bathymetries. Existing formulations of the specific yield function include weighting factors that impact the relative importance of the soil and open water specific yields on the composite value. Three formulations of the specific yield function from the literature were compared and found to produce varied results. Based on a comparison with empirical estimates of specific yield based on observed ratios of net precipitation to water level rise, one of the existing formulations is generalized and recommended for general use. The recommended function is dependent on wetland bathymetry, magnitude of the diurnal fluctuation, spatial extent of the equilibration area, and soil‐specific yield. A sensitivity analysis was conducted to examine the relative importance of these variables. The specific yield function is independent of wetland size and is strongly dependent on the basin profile coefficient (p), an indication of wetland shape. For most natural wetlands, bathymetry strongly influences specific yield.
      PubDate: 2014-08-12T11:37:57.914103-05:
      DOI: 10.1111/jawr.12237
       
  • Estimating Current and Future Groundwater Resources of the Maldives
    • Authors: Ryan T. Bailey; Abedalrazq Khalil, Vansa Chatikavanij
      Pages: n/a - n/a
      Abstract: The water resources of the atolls of the Republic of Maldives are under continual threat from climatic and anthropogenic stresses, including land surface pollution, increasing population, drought, and sea‐level rise (SLR). These threats are particularly acute for groundwater resources due to the small land surface area and low elevation of each island. In this study, the groundwater resources, in terms of freshwater lens thickness, total volume of fresh groundwater, and safe yield are estimated for the 52 most populous islands of the Maldives for current conditions and for the year 2030, with the latter accounting for projected SLR and associated shoreline recession. An algebraic model, designed in previous studies to estimate the lens thickness of atoll islands, is expanded in this study to also estimate volume of groundwater. Results indicate that average current lens thickness, groundwater volume, and per capita safe yield are approximately 4.6 m, 1,300 million liters, and 300 l/day, and that these values will decrease by approximately 10, 11, and 34%, respectively, by the year 2030. Based on results, it is demonstrated that groundwater, in terms of quantity, is a viable source of water for the islands of the Maldives both now and in coming decades, particularly for islands with large surface area and low population. Study results can provide water resource managers and government officials with valuable data for consideration in water security measures.
      PubDate: 2014-08-12T11:37:51.063294-05:
      DOI: 10.1111/jawr.12236
       
  • Controls on Temperature in Salmonid‐Bearing Headwater Streams in Two
           Common Hydrogeologic Settings, Kenai Peninsula, Alaska
    • Authors: Michael K. Callahan; Mark C. Rains, Jason C. Bellino, Coowe M. Walker, Steven J. Baird, Dennis F. Whigham, Ryan S. King
      Pages: n/a - n/a
      Abstract: Headwater streams are the most numerous in terms of both number and length in the conterminous United States and play important roles as spawning and rearing grounds for numerous species of anadromous fish. Stream temperature is a controlling variable for many physical, chemical, and biological processes and plays a critical role in the overall health and integrity of a stream. We investigated the controls on stream temperature in salmon‐bearing headwater streams in two common hydrogeologic settings on the Kenai Peninsula, Alaska: (1) drainage‐ways, which are low‐gradient streams that flow through broad valleys; and (2) discharge‐slopes, which are high gradient streams that flow through narrow valleys. We hypothesize local geomorphology strongly influences surface‐water and groundwater interactions, which control streamflow at the network scale and stream temperatures at the reach scale. The results of this study showed significant differences in stream temperatures between the two hydrogeologic settings. Observed stream temperatures were higher in drainage‐way sites than in discharge‐slope sites, and showed strong correlations as a continuous function with the calculated topographic metric flow‐weighted slope. Additionally, modeling results indicated the potential for groundwater discharge to moderate stream temperature is not equal between the two hydrogeologic settings, with groundwater having a greater moderating effect on stream temperature at the drainage‐way sites.
      PubDate: 2014-08-12T11:37:45.295675-05:
      DOI: 10.1111/jawr.12235
       
  • Evaluating the Eco‐Geomorphological Condition of Restored Streams
           Using Visual Assessment and Macroinvertebrate Metrics
    • Authors: Barbara A. Doll; Gregory D. Jennings, Jean Spooner, David L. Penrose, Joseph L. Usset
      Pages: n/a - n/a
      Abstract: The Stream Performance Assessment (SPA), a new rapid assessment method, was applied to 93 restored, 21 impaired, 29 reference, and 13 reference streams with some incision throughout North Carolina. Principal component analysis (PCA) indicated restored streams align more closely with reference streams rather than impaired streams. Further, PCA‐based factor analysis revealed restored streams were similar to reference streams in terms of morphologic condition, but exhibited a greater range of scores relative to aquatic habitat and bedform. Macroinvertebrate sampling and GIS watershed analyses were conducted on 84 restored streams. SPA and watershed data were compared to Ephemeroptera, Plecoptera, and Trichoptera (EPT) taxa to determine which factors indicate stream health. SPA and watershed factors were used in least squares, ridge, and principal component regression (PCR) to develop a prediction model for EPT taxa. All three methods produced reasonable predictions for EPT taxa. Cross‐validation indicated ridge regression resulted in the lowest prediction error. The ridge model was then used to predict EPT taxa numbers for 21 impaired and 25 reference streams in addition to the 84 restored streams. Statistical comparisons of the predicted scores indicated urban streams (>10% impervious watershed cover) have lower expected numbers of EPT taxa. Rural restored streams have macroinvertebrate metric scores similar to those predicted for rural reference streams.
      PubDate: 2014-08-12T11:37:33.277786-05:
      DOI: 10.1111/jawr.12233
       
  • Hydrological Responses to Climate and Land‐Use Changes along the
           North American East Coast: A 110‐Year Historical Reconstruction
    • Authors: Qichun Yang; Hanqin Tian, Marjorie A.M. Friedrichs, Mingliang Liu, Xia Li, Jia Yang
      Pages: n/a - n/a
      Abstract: The North American east coast (NAEC) region experienced significant climate and land‐use changes in the past century. To explore how these changes have affected land water cycling, the Dynamic Land Ecosystem Model (DLEM 2.0) was used to investigate the spatial and temporal variability of runoff and river discharge during 1901‐2010 in the study area. Annual runoff over the NAEC was 420 ± 61 mm/yr (average ± standard deviation). Runoff increased in parts of the northern NAEC but decreased in some areas of the southern NAEC. Annual freshwater discharge from the study area was 378 ± 61 km3/yr (average ± standard deviation). Factorial simulation experiments suggested that climate change and variability explained 97.5% of the interannual variability of runoff and also resulted in the opposite changes in runoff in northern and southern regions of the NAEC. Land‐use change reduced runoff by 5‐22 mm/yr from 1931 to 2010, but the impacts were divergent over the Piedmont region and Coastal Plain areas of the southern NAEC. Land‐use change impacts were more significant at local and watershed spatial scales rather than at regional scales. Different responses of runoff to changing climate and land‐use should be noted in future water resource management. Hydrological impacts of afforestation and deforestation as well as urbanization should also be noted by land‐use policy makers.
      PubDate: 2014-08-12T11:35:40.486492-05:
      DOI: 10.1111/jawr.12232
       
  • Evaluating the Impacts of Environmental Flow Alternatives on Reservoir and
           Recreational Operations Using System Dynamics Modeling
    • Authors: Ryan R. Morrison; Mark C. Stone
      Pages: n/a - n/a
      Abstract: Providing environmental flows is increasingly a management obligation in many water resource systems. Evaluating the impacts of environmental flow alternatives on other water uses in a basin can be a challenge, especially when collaborating with stakeholders. We demonstrate the use of system dynamics (SD) modeling to assess the impacts of four environmental flow alternatives in the Rio Chama, New Mexico. The model was developed to examine impacts of each alternative on reservoir storage and releases, hydropower production and revenue, and whitewater boating access. We simulated each alternative within a stochastic framework in order to explicitly incorporate hydrologic uncertainty into the analyses. The environmental flow alternatives were developed at a collaborative workshop of geomorphology, hydrology, and ecology experts. Results from the model indicate that the proposed flow recommendations on the Rio Chama will generally decrease annual reservoir storage, increase median flows, and have minimal impacts on hydropower production and whitewater rafting on the system. The Rio Chama case study is a promising example of how SD modeling can be used in the early stages of environmental flow studies and why it is compatible with collaborative modeling.
      PubDate: 2014-08-12T11:35:31.597753-05:
      DOI: 10.1111/jawr.12231
       
  • Conditional Water Rights in the Western United States: Introducing
           Uncertainty to Prior Appropriation?
    • Authors: Charles J.P. Podolak; Martin Doyle
      Pages: n/a - n/a
      Abstract: In the prior‐appropriation water rights regimes that prevail in the arid western United States, claims to annually variable surface water flows are fulfilled based on the order of their establishment. The two‐step process used to establish an appropriative water right in all 17 conterminous western states creates a temporary phase, or conditional water right, which has a priority date but no actual water use. We provide a review of the legal basis for these conditional water rights and demonstrate the potential uncertainty they introduce to current water users. We then present a complete census of conditional water rights in Colorado, including their amounts, ages, and uses. At the end of 2012 there were a large number of conditional water rights in Colorado (some over 90 years old) equal to 61% of the perfected water rights. Many of the controversial conditional water rights in Colorado have been associated with unconventional oil production in the northwestern portion of the state; however, conditional water rights are ubiquitous across the state and across many use types. In several basins, their existence can introduce uncertainty to some of the most senior water rights holders. Nevertheless, in most of the state, the effects of conditional water rights are restricted to a relatively junior class of water users. This work quantifies for the first time the result, in one state, of a peculiar aspect of water law common across all western prior‐appropriation states.
      PubDate: 2014-08-12T11:35:25.142257-05:
      DOI: 10.1111/jawr.12229
       
  • Analysis of Daily Peaking and Run‐of‐River Operations with
           Flow Variability Metrics, Considering Subdaily to Seasonal Time Scales
    • Authors: Nicholas A. Haas; Ben L. O'Connor, John W. Hayse, Mark S. Bevelhimer, Theodore A. Endreny
      Pages: n/a - n/a
      Abstract: Environmental flows are an important consideration in licensing hydropower projects as operational flow releases can result in adverse conditions for downstream ecological communities. Flow variability assessments have typically focused on pre‐ and post‐dam conditions using metrics based on daily averaged flow values. This study used subdaily and daily flow data to assess environmental flow response to changes in hydropower operations from daily peaking to run‐of‐river. An analysis tool was developed to quantify flow variability metrics and was applied to four hydropower projects. Significant differences were observed between operations at the 99% confidence level in the median flow values using hourly averaged flow datasets. Median daily rise and fall rates decreased on average 34.5 and 27.9%, respectively, whereas median hourly rise and fall rates decreased on average 50.1 and 50.6%, respectively. Differences in operational flow regimes were more pronounced in the hourly averaged flow datasets and less pronounced or nonexistent in the daily averaged flow datasets. These outcomes have implications for the development of ecology‐flow relationships that quantify effects of flow on processes such as fish stranding and displacement, along with habitat stability. Results indicate that flow variability statistics should be quantified using subdaily datasets to accurately represent the nature of hydropower operations, especially for daily peaking facilities.
      PubDate: 2014-07-22T16:11:33.879795-05:
      DOI: 10.1111/jawr.12228
       
  • Evaluating Pre‐ and Post‐Fire Peak Discharge Predictions
           across Western U.S. Watersheds
    • Authors: Alicia M. Kinoshita; Terri S. Hogue, Carolyn Napper
      Pages: n/a - n/a
      Abstract: This study reviews five models commonly used in post‐fire hydrologic assessments: the Rowe Countryman and Storey (RCS), United States Geological Survey (USGS) Linear Regression Equations, USDA Windows Technical Release 55 (USDA TR‐55), Wildcat5, and U.S. Army Corps of Engineers (USACE) Hydrologic Modeling System (HEC‐HMS). The models are applied to eight diverse basins in the western United States (U.S.) (Arizona, California, Colorado, Montana, and Washington) affected by wildfires and assessed by input parameters, calibration methods, model constraints, and performance. No one model is versatile enough for application to all study sites. Results show inconsistency between model predictions for events across the sites and less confidence with larger return periods (25‐ and 50‐year events) and post‐fire predictions. The RCS method performs well, but application is limited to southern California. The USGS linear regression model has wider regional application, but performance is less reliable at the large recurrence intervals and post‐fire predictions are reliant on a subjective modifier. Of the three curve number‐based models, Wildcat5 performs best overall without calibration, whereas the calibrated TR‐55 and HEC‐HMS models show significant improvement in pre‐fire predictions. Results from our study provide information and guidance to ultimately improve model selection for post‐fire prediction and encourage uniform parameter acquisition and calibration across the western U.S.
      PubDate: 2014-07-22T16:10:45.614054-05:
      DOI: 10.1111/jawr.12226
       
  • The Effects of Changing Land Cover on Streamflow Simulation in Puerto Rico
    • Authors: Ashley E. Van Beusekom; Lauren E. Hay, Roland J. Viger, William A. Gould, Jaime A. Collazo, Azad Henareh Khalyani
      Pages: n/a - n/a
      Abstract: This study quantitatively explores whether land cover changes have a substantive impact on simulated streamflow within the tropical island setting of Puerto Rico. The Precipitation Runoff Modeling System (PRMS) was used to compare streamflow simulations based on five static parameterizations of land cover with those based on dynamically varying parameters derived from four land cover scenes for the period 1953‐2012. The PRMS simulations based on static land cover illustrated consistent differences in simulated streamflow across the island. It was determined that the scale of the analysis makes a difference: large regions with localized areas that have undergone dramatic land cover change may show negligible difference in total streamflow, but streamflow simulations using dynamic land cover parameters for a highly altered subwatershed clearly demonstrate the effects of changing land cover on simulated streamflow. Incorporating dynamic parameterization in these highly altered watersheds can reduce the predictive uncertainty in simulations of streamflow using PRMS. Hydrologic models that do not consider the projected changes in land cover may be inadequate for water resource management planning for future conditions.
      PubDate: 2014-07-22T16:10:36.638861-05:
      DOI: 10.1111/jawr.12227
       
  • Characterizing a Major Urban Stream Restoration Project: Nine Mile Run
           (Pittsburgh, Pennsylvania, USA)
    • Authors: Daniel J. Bain; Erin M. Copeland, Marion T. Divers, Marijke Hecht, Kristina G. Hopkins, Justin Hynicka, Michael Koryak, Mary Kostalos, Lisa Brown, Emily M. Elliott, Joseph Fedor, Michele Gregorich, Brady Porter, Brenda Smith, Christopher Tracey, Margaret Zak
      Pages: n/a - n/a
      Abstract: Urban stream restoration continues to be used as an ecological management tool, despite uncertainty about the long‐term sustainability and resilience of restored systems. Evaluations of restoration success often focus on specific instream indicators, with limited attention to the wider basin or parallel hydrologic and geomorphic process. A comprehensive understanding of urban stream restoration progress is particularly important for comparisons with nonurban sites as urban streams can provide substantial secondary benefits to urban residents. Here, we utilize a wide range of indicators to retrospectively examine the restoration of Nine Mile Run, a multi‐million dollar stream restoration project in eastern Pittsburgh (Pennsylvania, USA). Examination of available continuous hydrological data illustrates the high cost of failures to incorporate the data into planning and adaptive management. For example, persistent extreme flows drive geomorphic degradation threatening to reverse hydrologic connections created by the restoration and impact the improved instream biotic communities. In addition, human activities associated with restoration efforts suggest a positive feedback as the stream restoration has focused effort on the basin beyond the reach. Ultimately, urban stream restoration remains a potentially useful management tool, but continued improvements in post‐project assessment should include examination of a wider range of indicators.
      PubDate: 2014-07-22T16:10:34.185659-05:
      DOI: 10.1111/jawr.12225
       
  • Bedded Sediment Conditions and Macroinvertebrate Responses in New Mexico
           Streams: A First Step in Establishing Sediment Criteria
    • Authors: Benjamin K. Jessup; Philip R. Kaufmann, Forrest John, Lynette S. Guevara, Seva Joseph
      Pages: n/a - n/a
      Abstract: Excess fine sediments in streambeds are among the most pervasive causes of degradation in streams of the United States. Simple criteria for acceptable streambed fines are elusive because streambed fines and biotic tolerances vary widely in the absence of human disturbances. In response to the need for sediment benchmarks that are protective of minimum aquatic life uses under the Clean Water Act, we undertook a case study using surveys of sediment, physical habitat, and macroinvertebrates from New Mexico streams. Our approach uses weight of evidence to develop suggested benchmarks for protective levels of surficial bedded sediments
      PubDate: 2014-07-22T16:10:31.677364-05:
      DOI: 10.1111/jawr.12224
       
  • Application of a Modified Health Belief Model to the
           Pro‐Environmental Behavior of Private Well Water Testing
    • Authors: Crista L. Straub; Jessica E. Leahy
      Pages: n/a - n/a
      Abstract: A social cognition model of health behavior, the health belief model, was applied to the pro‐environmental behavior of private well water testing. Conceptualizing environmental behaviors as health behaviors may provide new insight into pro‐environmental behavior change. A groundwater education program was provided to K‐12 children throughout New England. Both child participants and their parents completed surveys pertaining to private well water behavior. Results indicate that perceived barriers and socioeconomic status significantly influenced past well water testing of parent participants. Perceived barriers included: participants' concern related to the cost of treating their water, and how a well water problem would influence their property value. Parent participants also indicated that they would perform future well water testing if they received a reminder cue to action that might include: getting a discount or reminder in the mail, if a well testing program was available, and state or local requirement. Our findings reinforce the need for continued private well water research and parallels to additional environmental behaviors.
      PubDate: 2014-07-01T15:42:34.077708-05:
      DOI: 10.1111/jawr.12217
       
  • Flexibility in Water Resources Management: Review of Concepts and
           Development of Assessment Measures for Flood Management Systems
    • Authors: Kara N. DiFrancesco; Desiree D. Tullos
      Pages: n/a - n/a
      Abstract: Discussions around adapting water management systems to climate change often express the need to increase system flexibility. Yet despite the frequent use of the term flexibility, very little work has examined what exactly it means to have a flexible water management system, what features of a system make it more flexible than another system, or when the costs to implement flexible options outweigh the benefits gained from increased flexibility. To define and operationalize the concept of flexibility in the field of water resources management, this article reviews and analyzes concepts of flexibility from the fields of information technology, manufacturing, management, and adaptive social‐ecological systems. We identify five characteristics of flexible water resources systems, namely: slack, redundancy, connectivity, compatibility/coordination, and adjustability. We then operationalize the assessment of flexibility for flood management systems by proposing original flexibility metrics and discussing their application. We conclude with a discussion on the tradeoffs of increasing flexibility.
      PubDate: 2014-07-01T15:42:31.974297-05:
      DOI: 10.1111/jawr.12214
       
  • Price Determination and Efficiency in the Market for South Platte Basin
           Ditch Company Shares
    • Authors: Matthew T. Payne; Mark Griffin Smith, Clay J. Landry
      Pages: n/a - n/a
      Abstract: Water scarcity presents an obstacle to economic development in the western United States. Water rights markets help improve water allocation, allowing states to derive the highest economic benefit from available resources, and supporting new uses and economic development. However, the implicit (marginal) prices of water rights attributes are uncertain. To address this problem, we apply econometric analysis to a unique dataset to estimate the implicit values that market participants place on the attributes of shares of ditch company water rights in Colorado's South Platte River Basin. Our analysis demonstrates that ditch company share buyers value proximity of water diversion, reliability of water deliveries, and temporal flexibility of water use. To assess reliability we introduce the use of the coefficient of variation to capture, in one variable, the randomness of supply from ditch company shares that are not a single water right, but a portfolio of rights with different appropriation dates. Finally, we test and correct for spatial autocorrelation for the first time in a study of water market prices.
      PubDate: 2014-06-16T14:20:34.335241-05:
      DOI: 10.1111/jawr.12215
       
  • Estimation of Nonpoint Source Nitrate Concentrations in Indiana Rivers
           Based on Agricultural Drainage in the Watershed
    • Authors: Yan Jiang; Jane R. Frankenberger, Yinghui Sui, Laura C. Bowling
      Pages: n/a - n/a
      Abstract: Subsurface tile‐drained agricultural fields are known to be important contributors to nitrate in surface water in the Midwest, but the effect of these fields on nitrate at the watershed scale is difficult to quantify. Data for 25 watersheds monitored by the Indiana Department of Environmental Management and located near a U.S. Geological Survey stream gage were used to investigate the relationship between flow‐weighted mean concentration (FWMC) of nitrate‐N and the subsurface tile‐drained area (DA) of the watershed. The tile DA was estimated from soil drainage class, land use, and slope. Nitrate loads from point sources were estimated based on reported flows of major permitted facilities with mean nitrate‐N concentrations from published sources. Linear regression models exhibited a statistically significant relationship between annual/monthly nonpoint source (NPS) nitrate‐N and DA percentage. The annual model explained 71% of the variation in FWMC of nitrate‐N. The annual and monthly models were tested in 10 additional watersheds, most with absolute errors within 1 mg/l in the predicted FWMC. These models can be used to estimate NPS nitrate for unmonitored watersheds in similar areas, especially for drained agricultural areas where model performance was strongest, and to predict the nitrate reduction when various tile drainage management techniques are employed.
      PubDate: 2014-06-16T14:20:23.633019-05:
      DOI: 10.1111/jawr.12216
       
  • Impacts of 21st‐Century Climate Change on Hydrologic Extreme in the
           Pacific Northwest Region of North America
    • Authors: Ingrid M. Tohver; Alan F. Hamlet, Se‐Yeun Lee
      Pages: n/a - n/a
      Abstract: Climate change projections for the Pacific Northwest (PNW) region of North America include warmer temperatures (T), reduced precipitation (P) in summer months, and increased P during all other seasons. Using a physically based hydrologic model and an ensemble of statistically downscaled global climate model scenarios produced by the Columbia Basin Climate Change Scenarios Project, we examine the nature of changing hydrologic extremes (floods and low flows) under natural conditions for about 300 river locations in the PNW. The combination of warming, and shifts in seasonal P regimes, results in increased flooding and more intense low flows for most of the basins in the PNW. Flood responses depend on average midwinter T and basin type. Mixed rain and snow basins, with average winter temperatures near freezing, typically show the largest increases in flood risk because of the combined effects of warming (increasing contributing basin area) and more winter P. Decreases in low flows are driven by loss of snowpack, drier summers, and increasing evapotranspiration in the simulations. Energy‐limited basins on the west side of the Cascades show the strongest declines in low flows, whereas more arid, water‐limited basins on the east side of the Cascades show smaller reductions in low flows. A fine‐scale analysis of hydrologic extremes over the Olympic Peninsula echoes the results for the larger rivers discussed above, but provides additional detail about topographic gradients.
      PubDate: 2014-06-05T11:34:35.554237-05:
      DOI: 10.1111/jawr.12199
       
  • Prediction of Annual Streambank Erosion for Sequoia National Forest,
           California
    • Authors: Hilda Kwan; Sherman Swanson
      Pages: n/a - n/a
      Abstract: Many bank erosion models have limitations that restrict their use in wildland settings. Scientists and land managers at the Sequoia National Forest would like to understand the mechanisms and rates of streambank erosion to evaluate management issues and post‐wildfire effects. This study uses bank erosion hazard index (BEHI) and near‐bank stress (NBS) methods developed in Rosgen (2006 Watershed Assessment of River Stability and Sediment Supply [WARSSS]) for predicting streambank erosion in a geographic area that is dominated by colluvium and in which streambank erosion modeling has not been previously evaluated. BEHI evaluates bank susceptibility to erosion based on bank angle, bank and bankfull height, rooting depth and density, surface protection, and stratification of material within the banks. NBS assesses energy distribution against the bank measured as a ratio of bankfull near‐bank maximum depth to mean bankfull depth. We compared BEHI classes and NBS to actual bank erosion measured from 2008 to 2012. This index predicted streambank erosion with clear separation among BEHI ratings with R2 values of 0.76 for extreme, 0.37 for high/very high, 0.49 for moderate, and 0.70 for low BEHI. The relationships between measured erosion and BEHI extend the application of BEHI/NBS to a new region where they can inform management priorities, afforestation, stream/riparian restoration projects, and potentially burned area rehabilitation.
      PubDate: 2014-05-21T13:06:08.90347-05:0
      DOI: 10.1111/jawr.12200
       
  • Large Biases in Regression‐Based Constituent Flux Estimates: Causes
           and Diagnostic Tools
    • Authors: Robert M. Hirsch
      Pages: n/a - n/a
      Abstract: It has been documented in the literature that, in some cases, widely used regression‐based models can produce severely biased estimates of long‐term mean river fluxes of various constituents. These models, estimated using sample values of concentration, discharge, and date, are used to compute estimated fluxes for a multiyear period at a daily time step. This study compares results of the LOADEST seven‐parameter model, LOADEST five‐parameter model, and the Weighted Regressions on Time, Discharge, and Season (WRTDS) model using subsampling of six very large datasets to better understand this bias problem. This analysis considers sample datasets for dissolved nitrate and total phosphorus. The results show that LOADEST‐7 and LOADEST‐5, although they often produce very nearly unbiased results, can produce highly biased results. This study identifies three conditions that can give rise to these severe biases: (1) lack of fit of the log of concentration vs. log discharge relationship, (2) substantial differences in the shape of this relationship across seasons, and (3) severely heteroscedastic residuals. The WRTDS model is more resistant to the bias problem than the LOADEST models but is not immune to them. Understanding the causes of the bias problem is crucial to selecting an appropriate method for flux computations. Diagnostic tools for identifying the potential for bias problems are introduced, and strategies for resolving bias problems are described.
      PubDate: 2014-05-21T13:05:18.939788-05:
      DOI: 10.1111/jawr.12195
       
  • Hydrologic Controls on Nitrogen and Phosphorous Dynamics in Relict Oxbow
           Wetlands Adjacent to an Urban Restored Stream
    • Authors: Melanie D. Harrison; Andrew J. Miller, Peter M. Groffman, Paul M. Mayer, Sujay S. Kaushal
      Pages: n/a - n/a
      Abstract: Although wetlands are known to be sinks for nitrogen (N) and phosphorus (P), their function in urban watersheds remains unclear. We analyzed water and nitrate (NO3−) and phosphate (PO43−) dynamics during precipitation events in two oxbow wetlands that were created during geomorphic stream restoration in Baltimore County, Maryland that varied in the nature and extent of connectivity to the adjacent stream. Oxbow 1 (Ox1) received 1.6‐4.2% and Oxbow 2 (Ox2) received 4.2‐7.4% of cumulative streamflow during storm events from subsurface seepage (Ox1) and surface flow (Ox2). The retention time of incoming stormwater ranged from 0.2 to 6.7 days in Ox1 and 1.8 to 4.3 days in Ox2. Retention rates in the wetlands ranged from 0.25 to 2.74 g N/m2/day in Ox1 and 0.29 to 1.94 g N/m2/day in Ox2. Percent retention of the NO3−‐N load that entered the wetlands during the storm events ranged from 64 to 87% and 23 to 26%, in Ox1 and Ox2, respectively. During all four storm events, Ox1 and Ox2 were a small net source of dissolved PO43− to the adjacent stream (i.e., more P exited than entered the wetland), releasing P at a rate of 0.23‐20.83 mg P/m2/day and 3.43‐24.84 mg P/m2/day, respectively. N and P removal efficiency of the oxbows were regulated by hydrologic connectivity, hydraulic loading, and retention time. Incidental oxbow wetlands have potential to receive urban stream and storm flow and to be significant N sinks, but they may be sources of P in urban watersheds.
      PubDate: 2014-05-09T14:59:27.613672-05:
      DOI: 10.1111/jawr.12193
       
  • Linking Landscape Characteristics and High Stream Nitrogen in the Oregon
           Coast Range: Red Alder Complicates Use of Nutrient Criteria
    • Authors: Effie A. Greathouse; Jana E. Compton, John Van Sickle
      Pages: n/a - n/a
      Abstract: Red alder (Alnus rubra), a nitrogen(N)‐fixing deciduous broadleaf tree, can strongly influence N concentrations in western Oregon and Washington. We compiled a database of stream N and GIS‐derived landscape characteristics in order to examine geographic variation in N across the Oregon Coast Range. Basal area of alder, expressed as a percent of watershed area, accounted for 37% and 38% of the variation in summer nitrate and total N (TN) concentrations, respectively. Relationships between alder and nitrate were strongest in winter when streamflow and landscape connections are highest. Distance to the coast and latitude, potential surrogates for sea salt inputs, and watershed area were also related to nitrate concentrations in an all‐subsets regression analysis, which accounted for 46% of the variation in summer nitrate concentrations. The model with the lowest Akaike's Information Criterion did not include developed or agricultural land cover, probably because few watersheds in our database had substantial levels of these land cover classes. Our results provide evidence, at a regional scale, that background sources and processes cause many Coast Range streams to exceed proposed nutrient criteria, and that the prevalence of a single tree species (N‐fixing red alder) exerts a dominant control over stream N concentrations across this region.
      PubDate: 2014-04-28T01:35:17.834988-05:
      DOI: 10.1111/jawr.12194
       
  • Decoupling Streamflow Responses to Climate Variability and Land Use/Cover
           Changes in a Watershed in Northern China
    • Authors: Junting Guo; Zhiqiang Zhang, Jie Zhou, Shengping Wang, Peter Strauss
      First page: 1425
      Abstract: Restored annual streamflow (Qr) and measured daily streamflow of the Chaohe watershed located in northern China and associated long-term climate and land use/cover data were used to explore the effects of land use/cover change and climate variability on the streamflow during 1961-2009. There were no significant changes in annual precipitation (P) and potential evapotranspiration, whereas Qr decreased significantly by 0.81 mm/yr (p 
      PubDate: 2014-06-16T14:21:51.551773-05:
      DOI: 10.1111/jawr.12197
       
  • Long-Term Trends of Specific Conductance in Waters Discharged by Coal-Mine
           Valley Fills in Central Appalachia, USA
    • Authors: Daniel M. Evans; Carl E. Zipper, Patricia F. Donovan, W. Lee Daniels
      First page: 1449
      Abstract: Anthropogenic salinization of freshwaters is a global concern. Coal surface mining causes release of dissolved sulfate, bicarbonate, calcium, magnesium, and other ions to surface waters in central Appalachia, USA, through practices that include mine rock disposal in valley fills (VFs). This region's surface waters naturally have low salinity, with specific conductance (SC, a salinity indicator) generally
      PubDate: 2014-06-16T14:21:23.143374-05:
      DOI: 10.1111/jawr.12198
       
  • Assessment of Quality for Middle Level and High School Student-Generated
           Water Quality Data
    • Authors: John M. Peckenham; Sarah K. Peckenham
      First page: 1477
      Abstract: Student scientists have analyzed groundwater used for drinking water in rural areas to understand groundwater quality. This was part of a greater effort to understand risks to drinking water. The data produced by middle level and high school students have not been accepted by experts because of concerns about method and student accuracy. We assessed the inherent errors associated with method accuracy, student precision, and sample variability to establish bounds for attainable trueness in water analyses. Analytical test kits and probes were evaluated for the determination of pH, conductivity, chloride, hardness, iron, total soluble metals, and nitrate. In terms of precision, all methods met or exceeded design specifications. Method trueness was variable and in general ranged from good to poor depending on method. A gage reproducibility and repeatability analysis of instrumental methods (pH and conductivity) partitioned the variances into student error (12-46%), instrumental error (8-21%), and random error (45-68%). Overall, student-generated data met some of the quality objectives consistent with the method limitations. Some methods exhibited a systematic bias and data adjustment may be necessary. Given good management of the student analyst process, it is possible to make precise and accurate measurements consistent with the methods specifications.
      PubDate: 2014-06-16T14:20:49.096852-05:
      DOI: 10.1111/jawr.12213
       
  • Reviewer Index ‐ 2014
    • Pages: 1641 - 1643
      PubDate: 2014-12-01T06:22:42.219343-05:
      DOI: 10.1111/jawr.12273
       
 
 
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