Authors:Marjan Belt; Thomas Bowen, Kimberley Slee, Vicky Forgie Pages: n/a - n/a Abstract: We present a simulation model developed to communicate a potential investment trap associated with using man‐made river engineering to protect built infrastructure. A small system dynamics model in STELLA™ was constructed following a collaborative model‐building process to increase understanding among stakeholders of the role natural capital plays in wealth creation. We set out to explore the dynamic relationship between investing tax revenue in natural capital (specifically forested headwaters and low land wetlands) rather than built capital (specifically stopbanks) for flood protection in the Manawatū watershed, New Zealand. Significant investment is currently required to maintain and enhance river engineering infrastructure and keep pace with changes in the river's geomorphology. Viewed from a systems perspective, we suggest diversion of a proportion of existing funding into restoration of forested headwaters on steep slopes and restoration of functioning wetlands on floodplains could in the longer term provide an effective approach to flood protection. Co‐benefits of increased natural capital include the ecosystem services nutrient cycling, sediment capture, water purification, biodiversity, pollination, and cultural and recreational values. Overcoming an investment trap requires a longer term perspective. This simple model consisting of two feedback loops and two delays aims to contribute to an ongoing stakeholder dialogue concerning the Manawatū River watershed in New Zealand. PubDate: 2013-05-13T15:04:57.473247-05: DOI: 10.1111/jawr.12063
Authors:Samuel Sandoval‐Solis; Rebecca L. Teasley, Daene C. McKinney, Gregory A. Thomas, Carlos Patiño‐Gomez Pages: n/a - n/a Abstract: This article describes the collaborative modeling process and the resulting water resources planning model developed to evaluate water management scenarios in the transboundary Rio Grande basin. The Rio Grande is a severely water stressed basin that faces numerous management challenges as it crosses numerous jurisdictional boundaries. A collaborative process was undertaken to identify and model water management scenarios to improve water supply for stakeholders, the environment, and international obligations of water delivery from Mexico to the United States. A transparent and open process of data collection, model building, and scenario development was completed by a project steering committee composed of university, nongovernmental, and governmental experts from both countries. The outcome of the process was a planning model described in this article, with data and operations that were agreed on by water planning officials in each country. Water management scenarios were created from stakeholder input and were modeled and evaluated for effectiveness with the planning model. PubDate: 2013-05-13T15:04:40.982128-05: DOI: 10.1111/jawr.12070
Authors:Richard N. Palmer; Hal E. Cardwell, Mark A. Lorie, William Werick Pages: n/a - n/a Abstract: Participatory planning applied to water resources has sparked significant interest and debate during the last decade. Recognition that models play a significant role in the formulation and implementation of design and management strategies has encouraged the profession to consider how such models can be best implemented. Shared Vision Planning (SVP) is a disciplined planning approach that combines traditional water resources planning methodologies with innovations such as structured public participation and the use of collaborative modeling, resulting in a more complete understanding and an integrative decision support tool. This study reviews these three basic components of SVP and explains how they are incorporated into a unified planning approach. The successful application of SVP is explored in three studies involving planning challenges: the National Drought Study, the Lake Ontario‐St. Lawrence River Study, and the Apalachicola‐Chattahoochee‐Flint/Alabama‐Coosa‐Tallapoosa River Basin Study. The article concludes by summarizing the advantages and limitations of this planning approach. PubDate: 2013-05-13T15:04:36.208453-05: DOI: 10.1111/jawr.12067
Authors:Charles G. Morton; Justin L. Huntington, Greg M. Pohll, Richard G. Allen, Kenneth C. McGwire, Scott D. Bassett Pages: n/a - n/a Abstract: Agricultural irrigation accounts for a large fraction of the total water use in the western United States. The Mapping Evapotranspiration at high Resolution with Internalized Calibration (METRIC) remote sensing energy balance model is being used to estimate historical agricultural water use in western Nevada to evaluate basin‐wide water budgets. Each METRIC evapotranspiration (ET) estimate must be calibrated by a trained user, which requires some iterative time investment and results in variation in ET estimates between users. An automated calibration algorithm for the METRIC model was designed to generate ET estimates comparable to those from trained users by mimicking the manual calibration process. Automated calibration allows for rapid generation of METRIC ET estimates with minimal manual intervention, as well as uncertainty and sensitivity analysis of the model. The variation in ET estimates generated by the automated calibration algorithm was found to be similar to the variation in manual ET estimates. Results indicate that uncertainty was highest for fields with low ET levels and lowest for fields with high ET levels, with a seasonal mean uncertainty of approximately 5% for all fields. In addition, in a blind comparison, automated daily and seasonal ET estimates compared well with flux tower measurement ET data at multiple sites. Automated methods can generate first‐order ET estimates that are similar to time intensive manual efforts with less time investment. PubDate: 2013-05-13T15:04:24.835829-05: DOI: 10.1111/jawr.12054
Authors:Pamela Nagler; Edward Glenn Pages: n/a - n/a Abstract: Tamarix leaf beetles (Diorhabda carinulata) have been widely released on western United States rivers to control introduced shrubs in the genus Tamarix, with the goals of saving water through removal of an assumed high water‐use plant, and of improving habitat value by removing a competitor of native riparian trees. We review recent studies addressing three questions: (1) to what extent are Tamarix weakened or killed by recurrent cycles of defoliation; (2) can significant water salvage be expected from defoliation; and (3) what are the effects of defoliation on riparian ecology, particularly on avian habit? Defoliation has been patchy at many sites, and shrubs at some sites recover each year even after multiple years of defoliation. Tamarix evapotranspiration (ET) is much lower than originally assumed in estimates of potential water savings, and are the same or lower than possible replacement plants. There is concern that the endangered southwestern willow flycatcher (Empidonax trailli extimus) will be negatively affected by defoliation because the birds build nests early in the season when Tamarix is still green, but are still on their nests during the period of summer defoliation. Affected river systems will require continued monitoring and development of adaptive management practices to maintain or enhance riparian habitat values. Multiplatform remote sensing methods are playing an essential role in monitoring defoliation and rates of ET on affected river systems. PubDate: 2013-05-13T15:04:07.111199-05: DOI: 10.1111/jawr.12053
Authors:David L. Jordan; Peggy Barroll Pages: n/a - n/a Abstract: A time series of estimates of irrigated area was developed for the Lower Rio Grande valley (LRG) in New Mexico from the 1970s to present day. The objective of the project was to develop an independent, accurate, and scientifically justifiable evaluation of irrigated area in the region for the period spanning from the mid‐1970s to the present. These area estimates were used in support of groundwater modeling of the LRG region, as well as for other analyses. This study used a remote‐sensing‐based methodology to evaluate overall irrigated area within the LRG. We applied a methodology that involved the normalization of vegetation indices derived from satellite imagery to get a more accurate estimation of irrigated area across multiple time periods and multiple Landsat platforms. The normalization allows more accurate evaluation of vegetation index data that span several decades. An accuracy assessment of the methodology and results from this study was performed using field‐collected crop data from the 2008 growing season. The comparisons with field data indicate that the accuracy of the remote‐sensing‐based estimates of historical irrigated area is very good, with rates of false positives (areas identified as irrigated that are not truly irrigated) of only about 4%, and rates of false negatives (areas identified as not irrigated that are truly irrigated) in the range of 0.6‐2.0%. PubDate: 2013-05-13T15:04:02.759958-05: DOI: 10.1111/jawr.12052
Authors:Jordan P. Beamer; Justin L. Huntington, Charles G. Morton, Greg M. Pohll Pages: n/a - n/a Abstract: Escalating concerns about water supplies in the Great Basin have prompted numerous water budget studies focused on groundwater recharge and discharge. For many hydrographic areas (HAs) in the Great Basin, most of the recharge is discharged by bare soil evaporation and evapotranspiration (ET) from phreatophyte vegetation. Estimating recharge from precipitation in a given HA is difficult and often has significant uncertainty, therefore it is often quantified by estimating the natural discharge. As such, remote sensing applications for spatially distributing flux tower estimates of ET and groundwater ET (ETg) across phreatophyte areas are becoming more common. We build on previous studies and develop a transferable empirical relationship with uncertainty bounds between flux tower estimates of ET and a remotely sensed vegetation index, Enhanced Vegetation Index (EVI). Energy balance‐corrected ET measured from 40 flux tower site‐year combinations in the Great Basin was statistically correlated with EVI derived from Landsat imagery (r2 = 0.97). Application of the relationship to estimate mean‐annual ETg from four HAs in western and eastern Nevada is highlighted and results are compared with previous estimates. Uncertainty bounds about the estimated mean ETg allow investigators to evaluate if independent groundwater discharge estimates are “believable” and will ultimately assist local, state, and federal agencies to evaluate expert witness reports of ETg, along with providing new first‐order estimates of ETg. PubDate: 2013-05-13T15:03:55.088669-05: DOI: 10.1111/jawr.12058
Authors:J. Philip Burkhalter; Timothy C. Martin, Richard G. Allen, Jeppe Kjaersgaard, Erin Wilson, Ray Alvarado, Jason S. Polly Pages: n/a - n/a Abstract: We compared two methods of estimating crop water consumption to assess whether remote sensing techniques provide consumptive use (CU) estimates commensurate with conventional methods. Using available historical satellite and meteorological data, we applied Mapping EvapoTranspiration at high Resolution using Internalized Calibration (METRIC) to 317,455 ha in the South Platte basin, in northeastern Colorado, for the 2001 irrigation season. We then compared these derived CU estimates with values calculated by using the Colorado Water Conservation Board's South Platte Decision Support System StateCU model. Evaluating the data by irrigation ditch service area, we disaggregated the output to allow for comparison by service area size, crop type, irrigation method, water supply source, and water availability. We concluded that METRIC is a suitable alternative to StateCU in the South Platte basin and could help to identify areas with inhibited crop growth or deficit irrigation practices. In addition, METRIC could be used as a complement to StateCU to refine StateCU model parameters, allowing for more accurate estimates of crop water shortages and groundwater recharge associated with irrigation delivery and application. PubDate: 2013-05-13T15:03:47.484774-05: DOI: 10.1111/jawr.12051
Authors:Gabriel B. Senay; Stefanie Bohms, Ramesh K. Singh, Prasanna H. Gowda, Naga M. Velpuri, Henok Alemu, James P. Verdin Pages: n/a - n/a Abstract: The increasing availability of multi‐scale remotely sensed data and global weather datasets is allowing the estimation of evapotranspiration (ET) at multiple scales. We present a simple but robust method that uses remotely sensed thermal data and model‐assimilated weather fields to produce ET for the contiguous United States (CONUS) at monthly and seasonal time scales. The method is based on the Simplified Surface Energy Balance (SSEB) model, which is now parameterized for operational applications, renamed as SSEBop. The innovative aspect of the SSEBop is that it uses predefined boundary conditions that are unique to each pixel for the “hot” and “cold” reference conditions. The SSEBop model was used for computing ET for 12 years (2000‐2011) using the MODIS and Global Data Assimilation System (GDAS) data streams. SSEBop ET results compared reasonably well with monthly eddy covariance ET data explaining 64% of the observed variability across diverse ecosystems in the CONUS during 2005. Twelve annual ET anomalies (2000‐2011) depicted the spatial extent and severity of the commonly known drought years in the CONUS. More research is required to improve the representation of the predefined boundary conditions in complex terrain at small spatial scales. SSEBop model was found to be a promising approach to conduct water use studies in the CONUS, with a similar opportunity in other parts of the world. The approach can also be applied with other thermal sensors such as Landsat. PubDate: 2013-05-13T15:03:32.954734-05: DOI: 10.1111/jawr.12057
Authors:Richard G. Allen; Ricardo Trezza, Ayse Kilic, Masahiro Tasumi, Hongjun Li Pages: n/a - n/a Abstract: The speed and direction of air flow through complex terrain are difficult to define. Both impact sensible and latent heat flux exchanges at the surface. Evapotranspiration (ET) models such as Mapping EvapoTranspiration at high Resolution with Internalized Calibration (METRIC™) estimate ET as a residual of the surface energy process and are thus sensitive to aerodynamics, including terrain‐induced impacts on roughness governing convective heat transfer (H). There is a need to explore the sensitivities of H estimation and thereby ET estimation to wind speed and terrain roughness in mountainous areas and to determine the merit of operating complex mesoscale wind field models in conjunction with the energy balance process. A sensitivity analysis is explored in METRIC where we increased wind speed in proportion to a relative elevation parameter and we increased aerodynamic roughness to assimilate impacts of relative terrain roughness, estimated in proportion to standard deviation of elevation within a 3 km locality. These aerodynamic modifications increased convective heat transfer in complex terrain and reduced estimated ET. In other sensitivity runs, we reduced estimated wind speed on estimated leeward slopes. Estimated ET with and without these sensitivity adjustments is shown for mountainous areas of Montana and Nevada. Changes in ET ranged from little change ( PubDate: 2013-05-13T15:03:09.548549-05: DOI: 10.1111/jawr.12055
Authors:Richard G. Allen; Boyd Burnett, William Kramber, Justin Huntington, Jeppe Kjaersgaard, Ayse Kilic, Carlos Kelly, Ricardo Trezza Pages: n/a - n/a Abstract: A remaining challenge to applying satellite‐based energy‐balance algorithms for operational estimation of evapotranspiration (ET) is the calibration of the energy‐balance model. Customized calibration for each image date is generally required to overcome biases associated with radiometric accuracy of the image, uncertainties in aerodynamic features of the landscape, background thermal conditions, and model assumptions. The CIMEC process (calibration using inverse modeling at extreme conditions) is an endpoint calibration procedure where near extreme conditions in the image are identified where the ET can be estimated and assigned. In the Mapping EvapoTranspiration at high Resolution with Internalized Calibration (METRIC™) energy‐balance model, two endpoints represent the dry and wet ends of the ET spectrum. Generally, user‐intervention is required to select locations in the image to produce best accuracy. To bring the METRIC and similar processes into the domain of less experienced operators, a consistent, reproducible, and dependable statistics‐based procedure is introduced where relationships between vegetation amount and surface temperature are used to identify a subpopulation of locations (pixels) in an image that may best represent the calibration endpoints. This article describes the background and logic for the statistical approach, how the statistics were developed, area of interest requirements and assumptions, adjustment for dry conditions in desert climates, and implementation in a common image processing environment (ERDAS Imagine). PubDate: 2013-05-13T15:03:07.254124-05: DOI: 10.1111/jawr.12056
Authors:William R. Michaud Pages: n/a - n/a Abstract: Does collaborative modeling improve water resource management outcomes? How does collaborative modeling improve these outcomes? Does it always work? Under what conditions is collaborative modeling most appropriate? With support from the U.S. Army Corps of Engineers' Institute for Water Resources (IWR), researchers developed an evaluation framework to help address these questions. The framework links the effects of collaborative modeling on decision‐making processes with improvements in the extent to which resource management decisions, practices, and policies balance societal needs. Both practitioners' and participants' experiences suggest that under the right circumstances, collaborative modeling can generate these beneficial outcomes. Researchers developed performance measures and a survey to systematically capture these experiences and evaluate the outcomes of collaborative modeling processes. The survey can provide immediate feedback during a project to determine whether collaborative modeling is having the desired effect and whether course correction is warranted. Over the longer term, the systematic evaluation of collaborative modeling processes will help demonstrate in what ways and under what circumstances collaborative modeling is effective, inform and improve best practices, and raise awareness among water resource planners regarding the use of collaborative modeling for resource management decisions. PubDate: 2013-05-13T15:03:02.003996-05: DOI: 10.1111/jawr.12066
Authors:Stacy Langsdale; Allyson Beall, Elizabeth Bourget, Erik Hagen, Scott Kudlas, Richard Palmer, Diane Tate, William Werick Pages: n/a - n/a Abstract: Collaborative Modeling for Decision Support integrates collaborative modeling with participatory processes to inform natural resources decisions. Practitioners and advocates claim that the approach will lead to better water management, balancing interests more effectively and reducing the likelihood of costly legal delays. These claims are easy to make, but the benefits will only be realized if the process is conducted effectively. To provide guidance for how to conduct an effective collaborative modeling process, a task committee cosponsored by the Environmental Water Resources Institute (EWRI) of the American Society of Civil Engineers and by the U.S. Army Corps of Engineers' Institute for Water Resources developed a set of Principles and Best Practices for anyone who might convene or conduct collaborative modeling processes. The guidance is intended for both conflict resolution professionals and modelers, and our goal is to integrate these two fields in a way that will improve water resources planning and decision making. Here, the set of eight principles is presented along with a selection of associated best practices, illustrated by two different case examples. The complete document is available at: http://www.computeraideddisputeresolution.us/bestpractices/. PubDate: 2013-05-13T15:02:55.939983-05: DOI: 10.1111/jawr.12065
Authors:Marjan Belt; Heike Schiele, Vicky Forgie Pages: n/a - n/a Abstract: Mediated Modeling (MM) refers to “model building with stakeholders,” enabling collaborative learning and decision support. This article presents results from the Integrated Freshwater Solutions (IFS — www.ifs.org.nz) action research project in the Manawatū River watershed, New Zealand. Water quality in the watershed often rates poorly, with the key issues being sedimentation, eutrophication, and habitat destruction. IFS is to develop and test MM to support collaborative and adaptive freshwater management. The project team was presented with the opportunity to collaborate with the Manawatū River Leaders' Forum (MRLF), an initiative driven by the Regional Council to improve water quality. This article describes the process of MM and how it was adapted to meet the needs of MRLF stakeholders. This highlights some important conditions for collaborative and adaptive capacity building. The MM/MRLF stakeholders, represented: industry, farming, local and regional authorities, environmental groups, and indigenous Māori iwi/hapū (tribe/sub‐tribe). This article describes how MM assisted early in the collaborative process to develop the following: (1) a shared and more integrated understanding of causes and effects and (2) a sense of the order of magnitude of the problems and the impact proposed solutions might have. It also describes how the context of politics, time, and resource constraints played an important role reverting to a more traditional planning approach part way through the process. PubDate: 2013-05-13T15:02:23.446923-05: DOI: 10.1111/jawr.12064
Authors:M.W. Rivera; D.P. Sheer, A.J. Miller Pages: n/a - n/a Abstract: This study examines the evolution of a microworld created in a stakeholder process into educational materials used in a classroom setting. Microworlds have been used to stimulate learning through engagement in classroom and professional settings, but to our knowledge this is the first example that demonstrates utilization of the same process in both settings in the field of water resources, involving collaboration between the educational and professional sectors. An interdisciplinary role‐playing course in Computer‐Aided Negotiations (CAN) of water disputes is used as a case study. Upper‐level undergraduate students of varied academic backgrounds interacted in both the CAN process and river basin management model used in the CAN process as microworlds for one semester. We found evidence of meaningful engagement with both the process and model by all students. This finding has implications for engaging stakeholders without technical backgrounds in CAN processes. Students reported learning gains on surveys and pre/posttest scores improved, although only one item showed a statistically significant increase. During and after the teaching of this course, there was feedback of work products from the students to river basin managers. The course also provides the opportunity to learn the art of collaborative modeling through example and practice. Course materials are available at http://www.hydrologics.net/CAN_Course/. PubDate: 2013-05-13T15:02:11.35998-05:0 DOI: 10.1111/jawr.12069
Authors:A. Michael S. Sheer; Michael W. Nemeth, Daniel P. Sheer, Megan Ham, Michael Kelly, David Hill, Samuel D. Lebherz Pages: n/a - n/a Abstract: The Bow River Basin is a cornerstone of Alberta's development. In 2010, stakeholders representing interests from agriculture, municipalities, environment, and more formed the Bow River Project Research Consortium to help determine the potential for improving the operations in the basin. At present, upstream reservoirs are operated primarily for hydropower, whereas downstream reservoirs are operated for irrigation. Through Collaborative Modeling for Decision Support the stakeholders were able to develop a new method for operating the system that would dramatically improve environmental performance. The main components of the new operating strategy called for: purchase or setting aside of a small amount of storage volume in the power reservoirs; a set of rules for releases from that storage; an agreement by the major irrigation districts with the largest water licenses to utilize their ability to shift deliveries to and from their large offstream storage reservoirs to allow for increased instream flows, and to allow junior water license holders (mainly municipal and industrial supplies) an uninterrupted water supply; limitations of reservoir fluctuations to improve inreservoir habitat for fisheries; and increased minimum flows throughout the system leading to improved environmental outcomes. Costs of this strategy were minimal, impacts on power revenue were estimated at PubDate: 2013-05-13T15:02:07.093475-05: DOI: 10.1111/jawr.12068
Authors:Hund‐Der Yeh; Chih‐Tse Wang Pages: n/a - n/a Abstract: After the end of pumping the water level in the observation well starts to recover and the reduced drawdown during the recovery period is named as the residual drawdown. Traditional approaches in analyzing the data of residual drawdown for estimating the aquifer hydraulic parameters are mostly based on the application of superposition principle and Theis equation. In addition, the effect of wellbore storage is commonly ignored in the evaluation even if the test well has a finite diameter. In this article, we develop a mathematical model for describing the residual drawdown with considering the wellbore storage effect and the existing drawdown distribution produced by the pumping part of the test. The Laplace‐domain solution of the model is derived using the Laplace transform technique and the time‐domain result is inverted based on the Stehfest algorithm. This new solution shows that the residual drawdown associated with the boundary and initial conditions are related to the well drawdown and the aquifer drawdown, respectively. The well residual drawdown will be overestimated by the Theis residual drawdown solution in the early recovery part if neglecting the wellbore storage. On the other hand, the Theis residual drawdown solution can be used to approximate the present residual drawdown solution in the late recovery part of the test. PubDate: 2013-04-01T11:35:32.363713-05: DOI: 10.1111/jawr.12047
Authors:Dorcas H. Franklin; Jean L. Steiner, Sara E. Duke, Daniel N. Moriasi, Patrick J. Starks Pages: n/a - n/a Abstract: The Fort Cobb Watershed in Oklahoma has diverse biogeophysical settings and provides an opportunity to explore the association of water quality with a diverse set of landscapes during both wet (April 2007‐December 2009) and dry (January 2005‐March 2007) periods. The objective of this work was to identify spatial patterns in phosphorus (P) (soluble reactive P [SRP] and bioavailable P [BAP]) associated with landscape metrics for two distinct streamflow regimes. Spatial autocorrelation of P was evaluated using contiguous (side‐by‐side) and upstream (upstream:downstream) connectivity matrices. Biogeophysical metrics were compiled for each contributing area, and were partitioned based on association to P concentrations. Results for both SRP and BAP indicated that spatial autocorrelation was present (p PubDate: 2013-04-01T11:24:39.09339-05:0 DOI: 10.1111/jawr.12048
Authors:Lori A. Krider; Joseph A. Magner, Jim Perry, Bruce Vondracek, Leonard C. Ferrington Pages: n/a - n/a Abstract: Carbonate‐sandstone geology in southeastern Minnesota creates a heterogeneous landscape of springs, seeps, and sinkholes that supply groundwater into streams. Air temperatures are effective predictors of water temperature in surface‐water dominated streams. However, no published work investigates the relationship between air and water temperatures in groundwater‐fed streams (GWFS) across watersheds. We used simple linear regressions to examine weekly air‐water temperature relationships for 40 GWFS in southeastern Minnesota. A 40‐stream, composite linear regression model has a slope of 0.38, an intercept of 6.63, and R2 of 0.83. The regression models for GWFS have lower slopes and higher intercepts in comparison to surface‐water dominated streams. Regression models for streams with high R2 values offer promise for use as predictive tools for future climate conditions. Climate change is expected to alter the thermal regime of groundwater‐fed systems, but will do so at a slower rate than surface‐water dominated systems. A regression model of intercept vs. slope can be used to identify streams for which water temperatures are more meteorologically than groundwater controlled, and thus more vulnerable to climate change. Such relationships can be used to guide restoration vs. management strategies to protect trout streams. PubDate: 2013-04-01T11:24:16.815418-05: DOI: 10.1111/jawr.12046
Authors:Daniel A. Auerbach Pages: n/a - n/a Abstract: Doyle cogently describes advantages and concerns related to the system of United States river management in the context of its historical and political development. He rightly asserts the need for flexible, adaptable institutions in order to address changing societal demands. However, river management also requires certain inflexible standards in order to discern and prevent practices that undermine future human needs. Where modern scientific evidence converges with cultural traditions of stewardship, river managers can comfortably assert limits to specific patterns of use and to the malleability of restrictions. PubDate: 2013-04-01T11:24:06.468316-05: DOI: 10.1111/jawr.12045
Authors:Caitlin A. Grady; Adam P. Reimer, Jane Frankenberger, Linda Stalker Prokopy Pages: n/a - n/a Abstract: There is an increasing need to document the impacts of conservation‐related best management practices (BMPs) on water quality within a watershed. However, this impact analysis depends upon accurate geospatial locations of existing practices, which are difficult to obtain. This study demonstrates and evaluates three different methods for obtaining geospatial information for BMPs. This study was focused on the Eagle Creek Watershed, a mixed use watershed in central Indiana. We obtained geospatial information for BMPs through government records, producer interviews, and remote‐sensing aerial photo interpretation. Aerial photos were also used to validate the government records and producer interviews. This study shows the variation in results obtained from the three sources of information as well as the benefits and drawbacks of each method. Using only one method for obtaining BMP information can be incomplete, and this study demonstrates how multiple methods can be used for the most accurate picture. PubDate: 2013-03-22T11:45:32.340108-05: DOI: 10.1111/jawr.12041
Authors:Gabriele Villarini; James A. Smith Pages: n/a - n/a Abstract: Annual maximum peak discharge measurements from 62 stations with a record of at least 70 years are used to assess extreme flooding in Texas at the regional scale. This work focuses on examination of the validity of the stationarity assumption and on the impact of tropical cyclones (TCs) on the upper tail of the flood peak distribution. We assess the validity of the stationarity assumption by testing the records for abrupt and gradual changes. The presence of abrupt changes in the first two moments of the flood peak distribution is assessed using the Lombard test. We use the Mann‐Kendall test to examine the presence of monotonic trends. Results indicate that violations of the stationarity assumption are most commonly caused by abrupt changes, which are often associated with river regulation. We fit the time series of stationary flood records with the generalized extreme value distribution to investigate whether TCs control the upper tail of the flood peak distribution. Our results indicate that TCs play a diminished role in shaping the upper tail of the flood peak distribution compared with areas of the eastern United States subject to frequent TCs. PubDate: 2013-03-21T11:44:06.489426-05: DOI: 10.1111/jawr.12042
Authors:Li Chen; Markus Berli, Karletta Chief Pages: n/a - n/a Abstract: Wildfire can significantly change watershed hydrological processes resulting in increased risks for flooding, erosion, and debris flow. The goal of this study was to evaluate the predictive capability of hydrological models in estimating post‐fire runoff using data from the San Dimas Experimental Forest (SDEF), San Dimas, California. Four methods were chosen representing different types of post‐fire runoff prediction methods, including a Rule of Thumb, Modified Rational Method (MODRAT), HEC‐HMS Curve Number, and KINematic Runoff and EROSion Model 2 (KINEROS2). Results showed that simple, empirical peak flow models performed acceptably if calibrated correctly. However, these models do not reflect hydrological mechanisms and may not be applicable for predictions outside the area where they were calibrated. For pre‐fire conditions, the Curve Number approach implemented in HEC‐HMS provided more accurate results than KINEROS2, whereas for post‐fire conditions, the opposite was observed. Such a trend may imply fundamental changes from pre‐ to post‐fire hydrology. Analysis suggests that the runoff generation mechanism in the watershed may have temporarily changed due to fire effects from saturation‐excess runoff or subsurface storm dominated complex mechanisms to an infiltration‐excess dominated mechanism. Infiltration modeling using the Hydrus‐1D model supports this inference. Results of this study indicate that physically‐based approaches may better reflect this trend and have the potential to provide consistent and satisfactory prediction. PubDate: 2013-03-21T11:43:49.021793-05: DOI: 10.1111/jawr.12043
Authors:Stephanie L. Johnson; David R. Maidment, Mary J. Kirisits Pages: n/a - n/a Abstract: Bacterial contamination accounts for more than 60% of the impairments included on the 2008 Texas 303(d) List. Many of these bacterial impairments are along the Texas Gulf Coast because coastal waters often are regulated for oyster harvesting, which have strict water quality standards. Under the Clean Water Act, each one of these impaired waterbodies requires a total maximum daily load (TMDL) study to be performed. A recent, statewide study recommended the development and application of simple modeling approaches to address the majority of Texas's bacteria TMDLs, including “… simple load duration curve, GIS [geographic information systems], and/or mass balance models.” We developed the TMDL Balance model in response to this recommendation. TMDL Balance is a steady state, mass balance, GIS‐based model for simulating pollutant loads and concentrations in coastal systems. The model uses plug‐flow reactor and continuously‐stirred tank reactor equations to route spatially distributed point and nonpoint source loads through a watershed via overland flow, non‐tidal flow, and tidal flow, decaying the loads via first‐order kinetics. In this paper, we explain the development of the watershed loading portion of the TMDL Balance model, demonstrating the methodology through a case study: computing bacterial loads in the Copano Bay watershed of southeast Texas. The application highlights an example of distributing bacterial sources spatially based on land use data. PubDate: 2013-03-21T11:43:42.472337-05: DOI: 10.1111/jawr.12044
Authors:Ken M. Fritz; Elisabeth Hagenbuch, Ellen D'Amico, Molly Reif, Parker J. Wigington, Scott G. Leibowitz, Randy L. Comeleo, Joseph L. Ebersole, Tracie‐Lynn Nadeau Pages: n/a - n/a Abstract: Supreme Court cases have questioned if jurisdiction under the Clean Water Act extends to water bodies such as streams without year‐round flow. Headwater streams are central to this issue because many periodically dry, and because little is known about their influence on navigable waters. An accurate account of the extent and flow permanence of headwater streams is critical to estimating downstream contributions. We compared the extent and permanence of headwater streams from two field surveys with values from databases and maps. The first used data from 29 headwater streams in nine U.S. forests, whereas the second had data from 178 headwater streams in Oregon. Synthetic networks developed from the nine‐forest survey indicated that 33 to 93% of the channel lacked year‐round flow. Seven of the nine forests were predicted to have >200% more channel length than portrayed in the high‐resolution National Hydrography Dataset (NHD). The NHD and topographic map classifications of permanence agreed with ~50% of the field determinations across ~300 headwater sites. Classification agreement with the field determinations generally increased with increasing resolution. However, the flow classification on soil maps only agreed with ~30% of the field determination despite depicting greater channel extent than other maps. Maps that include streams regardless of permanence and size will aid regulatory decisions and are fundamental to improving water quality monitoring and models. PubDate: 2013-03-21T11:43:27.902403-05: DOI: 10.1111/jawr.12040
Authors:Anuradha M. Desai; Hanadi S. Rifai Pages: n/a - n/a Abstract: The variability of indicator bacteria over a fine resolution time scale on the order of minutes has yet to be fully understood. In this study, we collected more than 700 Escherichia coli samples at a 10‐ and 30‐min resolution in an urban watershed in Houston. A Bacteria Diurnal Sag (BDS) marked with daytime exponential decay followed by an exponential nighttime regeneration was observed. This pattern was observed during all sampled events but varied depending on other variables. The concentrations during a 24‐h period varied 1 to 5 orders of magnitude and the fecal load was at least 10 times lower than what would be obtained using a single morning E. coli measurement, the typical sampling scheme in most monitoring programs. Decay rates, ranging from 3.67 to 24.7/day, decreased E. coli concentrations to below the water‐quality standards from 14:00 to 18:00 h and were strongly influenced by water temperatures and solar radiation intensities. Rapid regeneration occurred on the order of 9.41 to 64.1/day allowing E. coli concentrations to return to their pre‐decay levels. The data indicated that four to six samples taken between 06:00 and 18:00 h may be sufficient to define the BDS depending on stream conditions, and that a threshold concentration of approximately 100 MPN/dl (most probable number in a deciliter) existed for the studied urban watershed. These findings have significant implications for water‐quality monitoring, regulation, and compliance. PubDate: 2013-03-15T12:56:43.460314-05: DOI: 10.1111/jawr.12039
Authors:Jennifer Steffen; Mark Jensen, Christine A. Pomeroy, Steven J. Burian Pages: n/a - n/a Abstract: This article presents an analysis of the projected performance of urban residential rainwater harvesting systems in the United States (U.S.). The objectives are to quantify for 23 cities in seven climatic regions (1) water supply provided from rainwater harvested at a residential parcel and (2) stormwater runoff reduction from a residential drainage catchment. Water‐saving efficiency is determined using a water‐balance approach applied at a daily time step for a range of rainwater cistern sizes. The results show that performance is a function of cistern size and climatic pattern. A single rain barrel (190 l [50 gal]) installed at a residential parcel is able to provide approximately 50% water‐saving efficiency for the nonpotable indoor water demand scenario in cities of the East Coast, Southeast, Midwest, and Pacific Northwest, but PubDate: 2013-03-15T12:56:38.522582-05: DOI: 10.1111/jawr.12038
Authors:Timothy H. Robinson; John M. Melack Pages: n/a - n/a Abstract: Nitrate and phosphate export coefficient models were developed for coastal watersheds along the Santa Barbara Channel in central California. One approach was based on measurements of nutrient fluxes in streams from specific land use classes and included a watershed response function that scaled export up or down depending on antecedent moisture conditions. The second approach for nutrient export coefficient modeling used anthropogenic nutrient loading for land use classes and atmospheric nutrient deposition to model export. In an application of the first approach to one watershed, the nitrate and phosphate models were within 20% of measured values for most storms. When applied to another year, both nitrate and phosphate models generally performed adequately with annual, storm‐flow, and base‐flow values within 20% of measured nutrient loadings. Less satisfactory results were found when applied to neighboring watersheds with difference percentages of land use and hydrologic conditions. Application of the second approach was less successful than the first approach. PubDate: 2013-03-15T12:55:41.180492-05: DOI: 10.1111/jawr.12037
Authors:William D. Shuster; Dennis Lye, Armah La Cruz, Lee K. Rhea, Katharine O'Connell, Amanda Kelty Pages: n/a - n/a Abstract: The collection, storage, and reuse of rainwater collected in rain barrels from urban rooftop areas assists municipalities in achieving stormwater management objectives and in some areas also serves as an adjunct resource for domestic water supplies. In this study, rainwater reuse and levels of select microbial indicators were monitored for six residential rain barrels located in the Shepherd Creek watershed of Cincinnati, Ohio. Water from rain barrels typically had poor microbial quality and was used for watering indoor and outdoor plants. Rain barrel water chemistry was slightly acidic, exhibited wide ranges in conductivity, turbidity, and total organic carbon (TOC) concentrations and gave no evidence of the presence of cyanobacterial microcystin toxins. Selected microbial water‐quality indicators indicated that counts of total coliform and enterococci were consistently above U.S. Environmental Protection Agency standards for secondary recreational contact water‐quality standards. Residential rain barrels can provide water appropriate for low‐contact reuses (such as plant watering), although there may be transient periods of high levels of indicator bacteria in the collected water. PubDate: 2013-03-15T12:55:30.576947-05: DOI: 10.1111/jawr.12036
Authors:Eric D. Stein; Matthew R. Cover, A. Elizabeth Fetscher, Clare O'Reilly, Roxana Guardado, Christopher W. Solek Pages: n/a - n/a Abstract: Armoring of streambanks is a common management response to perceived threats to adjacent infrastructure from flooding or erosion. Despite their pervasiveness, effects of reach‐scale bank armoring have received less attention than those of channelization or watershed‐scale hydromodification. In this study, we explored mechanistic ecosystem responses to armoring by comparing conditions upstream, within, and downstream of six stream reaches with bank armoring in Southern California. Assessments were based on four common stream‐channel assessment methods: (1) traditional geomorphic measures, (2) the California Rapid Assessment Method for wetlands, (3) bioassessment with benthic macroinvertebrates, and (4) bioassessment with stream algae. Although physical responses varied among stream types (mountain, transitional, and lowland), armored segments generally had lower slopes, more and deeper pools and fewer riffles, and increased sediment deposition. Several armored segments exhibited channel incision and bank toe failure. All classes of biological indicators showed subtle, mechanistic responses to physical changes. However, extreme heterogeneity among sites, the presence of catchment‐scale disturbances, and low sample size made it difficult to ascribe observed patterns solely to channel armoring. The data suggest that species‐level or functional group‐level metrics may be more sensitive tools than integrative indices of biotic integrity to local‐scale effects. PubDate: 2013-03-15T12:55:25.612557-05: DOI: 10.1111/jawr.12035
Abstract: Watershed managers often use physical geomorphic and habitat assessments in making decisions about the biological integrity of a stream, and to reduce the cost and time for identifying stream stressors and developing mitigation strategies. Such analysis is difficult since the complex linkages between reach‐scale geomorphic and habitat conditions, and biological integrity are not fully understood. We evaluate the effectiveness of a generalized regression neural network (GRNN) to predict biological integrity using physical (i.e., geomorphic and habitat) stream‐reach assessment data. The method is first tested using geomorphic assessments to predict habitat condition for 1,292 stream reaches from the Vermont Agency of Natural Resources. The GRNN methodology outperforms linear regression (69% vs. 40% classified correctly) and improves slightly (70% correct) with additional data on channel evolution. Analysis of a subset of the reaches where physical assessments are used to predict biological integrity shows no significant linear correlation, however the GRNN predicted 48% of the fish health data and 23% of macroinvertebrate health. Although the GRNN is superior to linear regression, these results show linking physical and biological health remains challenging. Reasons for lack of agreement, including spatial and temporal scale differences, are discussed. We show the GRNN to be a data‐driven tool that can assist watershed managers with large quantities of complex, nonlinear data.
Abstract: Water‐quality surveys have confirmed the presence of hormones and antibiotics in surface waters of the United States, which may be of concern to aquatic life. We investigated the concentrations of hormones and antibiotics in surface waters of the state of Delaware to determine – how they compared against environmental thresholds, how they varied across the state, and if they were correlated with land use type. Fifty surface water locations were sampled during early spring and late summer. Water samples were initially screened with ELISA followed by analysis with LC/MS/MS. The measured ranges of hormone concentrations were: 0‐3.71 ng/l for estrone, 0‐4.65 ng/l for estrone‐3‐sulfate, and 0‐6.27 ng/l for 17β‐estradiol. The measured ranges of antibiotics were: 0‐3.30 ng/l for sulfamerazine, 0‐10.74 ng/l for sulfamethoxazole, and 0‐2.29 ng/l for tetracycline. The predicted no‐effect concentration (PNEC) for estrone was exceeded for three samples and the PNEC for 17β‐estradiol was exceeded for 11 samples. In general, concentrations and detection frequencies were lower in the summer than the spring. The highest concentrations of hormones and antibiotics were spatially distributed in agricultural and urban areas; however, the correlations between land use type and the concentrations were weak. This study was the first statewide survey of hormones and antibiotics for Delaware and provided important baseline data on these emerging contaminants.
Abstract: Research was conducted at 28‐30 sites within eight study areas across the United States along a gradient of nutrient enrichment/agricultural land use between 2003 and 2007. Objectives were to test the application of an agricultural intensity index (AG‐Index) and compare among various invertebrate and algal metrics to determine indicators of nutrient enrichment nationally and within three regions. The agricultural index was based on total nitrogen and phosphorus input to the watershed, percent watershed agriculture, and percent riparian agriculture. Among data sources, agriculture within riparian zone showed significant differences among values generated from remote sensing or from higher resolution orthophotography; median values dropped significantly when estimated by orthophotography. Percent agriculture in the watershed consistently had lower correlations to invertebrate and algal metrics than the developed AG‐Index across all regions. Percent agriculture showed fewer pairwise comparisons that were significant than the same comparisons using the AG‐Index. Highest correlations to the AG‐Index regionally were −0.75 for Ephemeroptera, Plecoptera, and Trichoptera richness (EPTR) and −0.70 for algae Observed/Expected (O/E), nationally the highest was −0.43 for EPTR vs. total nitrogen and −0.62 for algae O/E vs. AG‐Index. Results suggest that analysis of metrics at national scale can often detect large differences in disturbance, but more detail and specificity is obtained by analyzing data at regional scales.
Abstract: Understanding the impacts that influence water quality is critical to the development of best management practices at the large watershed scale. This study describes the spatiotemporal variation in surface water quality and identifies their main impact in the Haihe River basin, China. Multivariate statistical techniques are applied to analyze the similarities among the sampling sites and to identify the main pollution sources in surface water. Results show that: (1) the basin can be clustered into two regions, water quality being better in the mountainous vs. plain regions; (2) water quality improves due to implementation of a strict state policy on environmental pollution control, prodded by the hosting of the Olympic games in the cities of Beijing and Tianjin; and (3) agricultural and residential land uses as well as livestock‐breeding are the main sources affecting water quality in the mountainous regions, whereas rural waste discharge — including domestic waste sewage, human and animal feces, and solid waste — significantly influences water quality in the plain regions. The waste discharge of industrial factories may be a significant source of water pollution in the plain regions. Results indicate that the environmental management from pollution sinks and sources, long‐lasting legal framework, and adequate economic incentives should be improved to optimize the large‐scale watershed management under the background of the rapid development of countries like China.
Abstract: Compensatory mitigation of impacted streams and wetlands has increased over the past two decades, with the associated industry spending over US$2.9 billion in aquatic restoration annually. Despite these expenditures, evaluations by the National Research Council and U.S. Government Accountability Office have provided evidence that compensatory mitigation practices are failing to protect aquatic resource functions and services, and vague federal policy and inadequate evaluation of compensatory mitigation projects are to blame. To address these weaknesses, an update to federal regulations on compensatory mitigation was released in 2008. Additionally, the 2012 Reissuance of Nationwide Permits, some of which affects compensatory stream mitigation, was recently published. Current policy, as reflected in these documents, still uses nonspecific language to direct compensatory stream mitigation leaving most implementation decisions to the local U.S. Army Corps of Engineers district. The majority of federal mitigation policy has focused on wetland compensation, with other aquatic resources receiving less attention (e.g., streams). In this article, weaknesses of current policy are discussed, as are suggested policy changes to minimize the loss of stream ecosystem functions and services. Compensatory mitigation policy should clearly define key terms, incorporate adaptive management procedures, and provide guidelines for determining mitigation costs and compensation ratio requirements.
Abstract: Salas, Jose D., 2013. Discussion “Pragmatic Approaches for Water Management Under Climate Change Uncertainty” by Eugene Z. Stakhiv. Journal of the American Water Resources Association (JAWRA). DOI : 10.1111/jawr.12026
Abstract: : Poppenga, Sandra K., Dean B. Gesch, and Bruce B. Worstell, 2013. Hydrography Change Detection: The Usefulness of Surface Channels Derived from LiDAR DEMs for Updating Mapped Hydrography. Journal of the American Water Resources Association (JAWRA) 1‐19. DOI : 10.1111/jawr.12027
The 1:24,000‐scale high‐resolution National Hydrography Dataset (NHD) mapped hydrography flow lines require regular updating because land surface conditions that affect surface channel drainage change over time. Historically, NHD flow lines were created by digitizing surface water information from aerial photography and paper maps. Using these same methods to update nationwide NHD flow lines is costly and inefficient; furthermore, these methods result in hydrography that lacks the horizontal and vertical accuracy needed for fully integrated datasets useful for mapping and scientific investigations. Effective methods for improving mapped hydrography employ change detection analysis of surface channels derived from light detection and ranging (LiDAR) digital elevation models (DEMs) and NHD flow lines. In this article, we describe the usefulness of surface channels derived from LiDAR DEMs for hydrography change detection to derive spatially accurate and time‐relevant mapped hydrography. The methods employ analyses of horizontal and vertical differences between LiDAR‐derived surface channels and NHD flow lines to define candidate locations of hydrography change. These methods alleviate the need to analyze and update the nationwide NHD for time relevant hydrography, and provide an avenue for updating the dataset where change has occurred.
Abstract: : Xie, Xianjun, Yanxin Wang, Junxia Li, Chunli Su, and Mengyu Duan, 2013. Hydrogeochemical and Isotopic Investigations on Groundwater Salinization in the Datong Basin, Northern China. Journal of the American Water Resources Association (JAWRA) 1‐13. DOI :10.1111/jawr.12028
Analyses of major elements, environmental isotope ratios (δ18O, δ2H), and PHREEQC inverse modeling investigations were conducted to understand the processes controlling the salinization of groundwater within the Datong Basin. The hydrochemical results showed that groundwater with high total dissolved solid (TDS) concentrations was dominated by sodium bicarbonate (Na‐HCO3), sodium chlorite (Na‐Cl), and sodium sulfate (Na‐SO4) type waters, whereas low‐TDS groundwater from near mountain areas was dominated by calcium bicarbonate (Ca‐HCO3) and magnesium bicarbonate (Mg‐HCO3) type waters. The characterization of the major components of groundwater and PHREEQC inverse modeling indicated that the aluminosilicate hydrolysis, cation exchange, and dissolution of evaporites (halite, mirabilite, and gypsum) governed the salinization of groundwater within the Datong Basin. The environmental isotope (δ18O, δ2H) and Cl−/Br− ratios revealed the impact of fast vertical recharge by irrigation returns and salt‐flushing water on the groundwater salinization. According to the analyses of major hydrochemical components and PHREEQC inverse modeling, evaporite dissolution associated with irrigation and salt‐flushing practice was probably the dominant controlling factor for the groundwater salinization, especially in the central part of the basin. Therefore, groundwater pumping for irrigation and salt‐flushing should be controlled to protect groundwater quality in this area.
Abstract: : Podolak, Charles J.P., 2013. Predicting the Planform Configuration of the Braided Toklat River, Alaska, with a Suite of Rule‐Based Models. Journal of the American Water Resources Association (JAWRA) 00(0):000‐0001‐12. DOI :10.1111/jawr.12029
An ensemble of rule‐based models was constructed to assess possible future braided river planform configurations for the Toklat River in Denali National Park and Preserve, Alaska. This approach combined an analysis of large‐scale influences on stability with several reduced‐complexity models to produce the predictions at a practical level for managers concerned about the persistence of bank erosion while acknowledging the great uncertainty in any landscape prediction. First, a model of confluence angles reproduced observed angles of a major confluence, but showed limited susceptibility to a major rearrangement of the channel planform downstream. Second, a probabilistic map of channel locations was created with a two‐parameter channel avulsion model. The predicted channel belt location was concentrated in the same area as the current channel belt. Finally, a suite of valley‐scale channel and braid plain characteristics were extracted from a light detection and ranging (LiDAR)‐derived surface. The characteristics demonstrated large‐scale stabilizing topographic influences on channel planform. The combination of independent analyses increased confidence in the conclusion that the Toklat River braided planform is a dynamically stable system due to large and persistent valley‐scale influences, and that a range of avulsive perturbations are likely to result in a relatively unchanged planform configuration in the short term.
Abstract: Acharya, Anil, Kenneth Lamb, and Thomas C. Piechota, 2012. Impacts of Climate Change on Extreme Precipitation Events over Flamingo Tropicana Watershed. Journal of the American Water Resources Association (JAWRA) 1‐12. DOI : 10.1111/jawr.12020
: Climate change, particularly the projected changes to precipitation patterns, is likely to affect runoff both regionally and temporally. Extreme rainfall events are expected to become more intense in the future in arid urban areas and this will likely lead to higher streamflow. Through hydrological modeling, this article simulates an urban basin response to the most intense storm under anthropogenic climate change conditions. This study performs an event‐based simulation for shorter duration storms in the Flamingo Tropicana (FT) watershed in Las Vegas, Nevada. An extreme storm, defined as a 100‐year return period storm, is selected from historical records and perturbed to future climatic conditions with respect to multimodel multiscenario (A1B, A2, B1) bias corrected and spatially disaggregated data from the World Climate Research Programme's (WCRP's) database. The cumulative annual precipitation for each 30‐year period shows a continuous decrease from 2011 to 2099; however, the summer convective storms, which are considered as extreme storms for the study area, are expected to be more intense in future. Extreme storm events show larger changes in streamflow under different climate scenarios and time periods. The simulated peak streamflow and total runoff volume shows an increase from 40% to more than 150% (during 2041‐2099) for different climate scenarios. This type of analysis can help evaluate the vulnerability of existing flood control system and flood control policies.
Abstract: Qiao, Lei, Robert B. Herrmann, and Zaitao Pan, 2012. Parameter Uncertainty Reduction for SWAT Using GRACE, Streamflow, and Groundwater Table Data for Lower Missouri River Basin. Journal of the American Water Resources Association (JAWRA) 1‐16. DOI : 10.1111/jawr.12021
: This study incorporates the newly available Gravity Recovery and Climate Experiment (GRACE) water storage data and water table data from well logs to reduce parameter uncertainty in Soil and Water Assessment Tool (SWAT) calibration using a SUFI2 (sequential uncertainty fitting) framework for the Lower Missouri River Basin. Model evaluations are performed in multiple stages using a multiobjective function consisting of multisite streamflow and GRACE water storage data as well as a groundwater component. Results show that (1) a model calibrated with both streamflow and GRACE data simultaneously can maintain the water balance for the whole basin, but may improperly partition surface flow and base flow. Additional inclusion of the groundwater constraint can significantly improve the model performance in groundwater hydrological processes. In our case, the estimation of specific yield of shallow aquifers has been increased to 10−2 from previous much underestimated level (
Abstract: McDaniel, Rachel L., Michelle L. Soupir, Ross B. Tuttle, and Amy E. Cervantes, 2012. Release, Dispersion, and Resuspension of Escherichia coli from Direct Fecal Deposits Under Controlled Flows. Journal of the American Water Resources Association (JAWRA) 1‐9. DOI : 10.1111/jawr.12022
: Water‐quality standards have been placed on fecal indicator organisms such as Escherichia coli in an attempt to limit the concentrations in water bodies. Cattle can be a significant source of bacteria to water systems, particularly when they are allowed direct access to streams. A flume study was conducted to quantify the effect and understand the transport of E. coli from directly deposited cattle manure. Five steady‐state flows, ranging from 0.00683 to 0.0176 m3/s, were studied and loads from a single cowpie exceeded the U.S. Environmental Protection Agency’s recommended water‐quality standards (235 CFU/100 ml) at each flow over the hour study period. Average E. coli concentrations ranged from 102 to 105 CFU/100 ml over the hour sampling period for all flows. High spatial variations in E. coli concentrations were often seen at each sampling time, with higher concentrations typically at the bottom of the flume. E. coli resuspension was initially greater at 0.5 min after deposition, for the lowest flow (105 CFU/m2/s); however, resuspension rates became similar over time, on the order of 103 CFU/m2/s. This study demonstrates that the concentrations of E. coli can vary over the water column, and therefore grab samples may inaccurately measure bacteria concentrations and loads in streams. In addition, resuspension rates were often high, so the incorporation of this process into water‐quality models is important for bacteria prediction.
Abstract: Hester, Erich T. and Kalen S. Bauman, 2012. Stream and Retention Pond Thermal Response to Heated Summer Runoff from Urban Impervious Surfaces. Journal of the American Water Resources Association (JAWRA) 1‐15. DOI : 10.1111/jawr.12019
: Runoff from parking lots during summer storms injects surges of hot water into receiving water bodies. We present temperature data collected near urban storm sewer outfalls in Blacksburg, Virginia, using arrays of sensors in a stream and a stormwater pond. Surges occurred roughly a dozen times per month, ranging up to 8.1°C with average duration 2 h in the stream and up to 11.2°C with average duration 7 h in the pond. Surges were larger in the pond due to a larger contributing watershed, no dilution by upstream water, and cool background temperatures near the outfall. Surges began abruptly, warming at rates averaging 0.2°C/min for periods of 5‐20 min. Surges dissipated as they propagated into the water bodies, travelling further in the stream (>19 m) than the pond (∼10 m) consistent with greater advection in the stream. Surges were largest and most frequent in the afternoon but occurred at all times of day and night. Stream surges exhibited two phases: an early high‐temperature low‐volume input from the storm sewer and a later low‐temperature high‐volume input from upstream. Surges at the pond did not exhibit two phases, consistent with inputs only from storm sewers. Surges are likely common in urban areas, and may cumulatively have consequences for aquatic organisms, biogeochemical process rates, and even human health. Such effects may be compounded by urban heat islands and climate change, so prevention or mitigation should be considered.
Abstract: Meador, Michael R., 2012. Nutrient Enrichment and Fish Nutrient Tolerance: Assessing Biologically Relevant Nutrient Criteria. Journal of the American Water Resources Association (JAWRA) 1‐11. DOI : 10.1111/jawr.12015
: Relationships between nutrient concentrations and fish nutrient tolerance were assessed relative to established nutrient criteria. Fish community, nitrate plus nitrite (nitrate), and total phosphorus (TP) data were collected during summer low‐flow periods in 2003 and 2004 at stream sites along a nutrient‐enrichment gradient in an agricultural basin in Indiana and Ohio and an urban basin in the Atlanta, Georgia, area. Tolerance indicator values for nitrate and TP were assigned for each species and averaged separately for fish communities at each site (TIVo). Models were used to predict fish species expected to occur at a site under minimally disturbed conditions and average tolerance indicator values were determined for nitrate and TP separately for expected communities (TIVe). In both areas, tolerance scores (TIVo/TIVe) for nitrate increased significantly with increased nitrate concentrations whereas no significant relationships were detected between TP tolerance scores and TP concentrations. A 0% increase in the tolerance score (TIVo/TIVe = 1) for nitrate corresponded to a nitrate concentration of 0.19 mg/l (compared with a USEPA summer nitrate criterion of 0.17 mg/l) in the urban area and 0.31 mg/l (compared with a USEPA summer nitrate criterion of 0.86 mg/l) in the agricultural area. Fish nutrient tolerance values offer the ability to evaluate nutrient enrichment based on a quantitative approach that can provide insights into biologically relevant nutrient criteria.
Abstract: Kurian, Lisa M., Laura K. Lautz, and Myron J. Mitchell, 2012. Winter Hydrology and NO3− Concentrations in a Forested Watershed: A Detailed Field Study in the Adirondack Mountains of New York. Journal of the American Water Resources Association (JAWRA) 1-20. DOI : 10.1111/jawr.12012
: More than 85% of NO3− losses from watersheds in the northeastern United States are exported during winter months (October 1 to May 30). Interannual variability in NO3− loads to individual streams is closely related to interannual climatic variations, particularly during the winter. The objective of our study was to understand how climatic and hydrogeological factors influence NO3− dynamics in small watersheds during the winter. Physical parameters including snow depth, soil temperature, stream discharge, and water table elevation were monitored during the 2007-2008 winter in two small catchments in the Adirondack Mountains, New York State. Snowpack persisted from mid-December to mid-April, insulating soils such that only two isolated instances of soil frost were observed during the study period. NO3− export during a mid-winter rain-on-snowmelt event comprised between 8 and 16% of the total stream NO3− load for the four-month winter study period. This can be compared with the NO3− exported during the final spring melt, which comprised between 38 and 45% of the total four-month winter NO3− load. Our findings indicate that minor melt events were detectable with changes in soil temperature, streamflow, groundwater level, and snow depth. But, based on loading, these events were relatively minor contributors to winter NO3− loss. A warmer climate and fluctuating snowpack may result in more major mid-winter melt events and greater NO3− export to surface waters.
Abstract: Rosenquist, Shawn E., Jason W. Moak, and Oscar P. Flite, 2012. Modeling Biochemical Oxygen Demand Through the Middle and Lower Savannah River. Journal of the American Water Resources Association (JAWRA) 1-16. DOI : 10.1111/jawr.12014
: In order to improve modeling accuracy and general understanding of lotic biochemical oxygen demand (BOD), this study characterized river metabolism with the current Georgia Environmental Protection Division method for the middle and lower Savannah River basin (MLSRB) and several alternative methods developed with 120-day, long-term biochemical oxygen demand (LTBOD) data from the MLSRB. The data were a subset of a larger two-year LTBOD study to characterize and understand BOD in the MLSRB, located approximately between Augusta, Georgia, and Savannah, Georgia, along the border of Georgia and South Carolina. The LTBOD data included total oxygen loss and nitrogen speciation for separately quantifying nitrification. Results support the following insights and opportunities for modeling methods: (1) it is important to modeling accuracy that residuals be checked for even dispersion to avoid areas of over- and underprediction; (2) modeling with bounded, yet unfixed, rates is a sufficiently simple alternative to fixed-rate modeling that can eliminate the need for manual adjustments and provide additional system understanding to inform regulation; (3) if fixed rates modeling is desired, model quality for this system might be improved through revising the current low rate (along with the associated f-ratio updates) from 0.02/day rate to 0.006/day and potentially adding a new rate at 1.0/day in some cases; and (4) the current 57/43 ratio of slow/fast BOD is reasonable based on the 52/45/3 slow/fast/faster BOD proportions of this study.
Abstract: Joseph, John F., Hatim O. Sharif, Jeffrey G. Arnold, and David D. Bosch, 2012. The Impact of Asynchronicity on Event-Flow Estimation in Basin-Scale Hydrologic Model Calibration. Journal of the American Water Resources Association (JAWRA) 1-19. DOI : 10.1111/jawr.12011
: The calibration of basin-scale hydrologic models consists of adjusting parameters such that simulated values closely match observed values. However, due to inevitable inaccuracies in models and model inputs, simulated response hydrographs for multiyear calibrations will not be perfectly synchronized with observed response hydrographs at the daily time step. An analytically derived formula suggests that when timing errors are significant, traditional calibration approaches may generally underestimate the total event-flow volume. An event-adaptive time series is developed and incorporated into the Nash-Sutcliffe Efficiency objective function to diagnose the potential impact of event-flow synchronization errors. Test sites are the 50 km2 Subwatershed I of the Little River Experimental Watershed (LREWswI) in southeastern Georgia, and the 610 km2 Little Washita River Experimental Watershed (LWREW) in southwestern Oklahoma, with the Soil and Water Assessment Tool used as the hydrologic model. Results suggest that simulated surface runoff generation is 55% less for LREWswI when the daily time series is used compared with when the event-adaptive technique is used. Event-flow generation may also be underestimated for LWREW, but to a lesser extent than it may be for LREWswI, due to a larger portion of the event flow being lateral flow.
Abstract: Richards, R. Peter, Ibrahim Alameddine, J. David Allan, David B. Baker, Nathan S. Bosch, Remegio Confesor, Joseph V. DePinto, David M. Dolan, Jeffrey M. Reutter, and Donald Scavia, 2012. Discussion –“Nutrient Inputs to the Laurentian Great Lakes by Source and Watershed Estimated Using SPARROW Watershed Models” by Dale M. Robertson and David A. Saad. Journal of the American Water Resources Association (JAWRA) 1‐10. DOI : 10.1111/jawr.12006
: Results from the Upper Midwest Major River Basin (MRB3) SPARROW model and underlying Fluxmaster load estimates were compared with detailed data available in the Lake Erie and Ohio River watersheds. Fluxmaster and SPARROW estimates of tributary loads tend to be biased low for total phosphorus and high for total nitrogen. These and other limitations of the application led to an overestimation of the relative contribution of point sources vs. nonpoint sources of phosphorus to eutrophication conditions in Lake Erie, when compared with direct estimates for data‐rich Ohio tributaries. These limitations include the use of a decade‐old reference point (2002), lack of modeling of dissolved phosphorus, lack of inclusion of inputs from the Canadian Lake Erie watersheds and from Lake Huron, and the choice to summarize results for the entire United States Lake Erie watershed, as opposed to the key Western and Central Basin watersheds that drive Lake Erie’s eutrophication processes. Although the MRB3 SPARROW model helps to meet a critical need by modeling unmonitored watersheds and ranking rivers by their estimated relative contributions, we recommend caution in use of the MRB3 SPARRROW model for Lake Erie management, and argue that the management of agricultural nonpoint sources should continue to be the primary focus for the Western and Central Basins of Lake Erie.
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