Archive for June, 2013

Localized streambank armoring

Thursday, June 27th, 2013

Early View article:Reach-Scale Geomorphic and Biological Effects of Localized Streambank Armoring,” by Eric D. Stein, Matthew R. Cover, A. Elizabeth Fetscher, Clare O’Reilly, and Roxana Guardado.

This study 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.

[Please note: I have quoted and paraphrased freely from the article, but the interpretation is my own.]

Managing forests

Thursday, June 27th, 2013

Early View article:Managing Forests for Increased Regional Water Yield in the Southeastern U.S. Coastal Plain,” by Daniel L. McLaughlin, David A. Kaplan, and Matthew J. Cohen.

[Abstract] “With growing populations fueling increased groundwater abstraction and forecasts of greater water scarcity in the southeastern United States, identifying land management strategies that enhance water availability will be vital to maintaining hydrologic resources and protecting natural systems. Management of forested uplands for lower basal area, currently a priority for habitat improvement on public lands, may also increase water yield through decreased evapotranspiration (ET). To explore this hypothesis, we synthesized studies of precipitation and ET in coastal plain pine stands to develop a statistical model of water yield as a function of management strategy, stand structure, and ecosystem water use. This model allowed us to estimate changes in water yield in response to varying management strategies across spatial scales from the individual stand to a regional watershed. Results suggest that slash pine stands managed at lower basal areas can have up to 64% more cumulative water yield over a 25-year rotation compared to systems managed for high-density timber production, with the greatest increases in stands also managed for recurrent understory fire. Although there are important uncertainties in the magnitude of additional water yield and its final destination (i.e., surface water bodies vs. groundwater), this analysis highlights the potential for management activities on public and private timber lands to partially offset increasing demand on surface and groundwater resources.”

[Please note: I have quoted and paraphrased freely from the article, but the interpretation is my own.]

Water stress projections

Tuesday, June 25th, 2013

Early View article:Water Stress Projections for the Northeastern and Midwestern United States in 2060: Anthropogenic and Ecological Consequences,” by Brian G. Tavernia, Mark D. Nelson, Peter Caldwell, and Ge Sun.

The Northeast and Midwest have plenty of water, even considering climate change, right? This article takes a look at that hypothesis. Their finding: Yes, but some tradeoffs may be needed.

The authors used output from WaSSI, a water accounting model, to assess potential changes between 2010 and 2060 in (1) anthropogenic water stress for watersheds throughout the Northeast and Midwest and (2) native fish species richness (i.e., number of species) for the Upper Mississippi water resource region (UMWRR). Six alternative scenarios of climate change, land-use change, and human population growth indicated future water supplies will, on average across the region, be adequate to meet anthropogenic demands. Nevertheless, the number of individual watersheds experiencing severe stress (demand > supplies) was projected to increase for most scenarios, and some watersheds were projected to experience severe stress under multiple scenarios. Similarly, we projected declines in fish species richness for UMWRR watersheds and found the number of watersheds with projected declines and the average magnitude of declines varied across scenarios. All watersheds in the UMWRR were projected to experience declines in richness for at least two future scenarios. Many watersheds projected to experience declines in fish species richness were not projected to experience severe anthropogenic water stress, emphasizing the need for multidimensional impact assessments of changing water resources.

[Please note: I have quoted and paraphrased freely from the article, but the interpretation is my own.]

Verifying data

Monday, June 24th, 2013

Early View article:Locating Existing Best Management Practices Within a Watershed: The Value of Multiple Methods,” by Caitlin A. Grady, Adam P. Reimer, Jane Frankenberger, Linda Stalker Prokopy.

I liked this article because it exhibits a healthy distrust of data sources. 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. The authors 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.

[Please note: I have quoted and paraphrased freely from the article, but the interpretation is my own.]

2012 Impact Factor

Friday, June 21st, 2013

The 2012 Impact Factors were released yesterday and JAWRA now has an IF of 1.956.  The journal is ranked 19 out of 42 in Environmental Engineering, 59 out of 170 in Geosciences and 21 out of 80 in Water Resources. Congratulations are in order for the JAWRA Editorial Team, our authors, and everybody who has supported us over the years!

Headwater streams

Thursday, June 20th, 2013

Early View article:Comparing the Extent and Permanence of Headwater Streams from Two Field Surveys to Values from Hydrographic Databases and Maps,” by Ken M. Fritz, Elisabeth Hagenbuch, Ellen D’Amico, Molly Reif, Parker J. Wigington Jr., Scott G. Leibowitz, Randy L. Comeleo, Joseph L. Ebersole, and Tracie-Lynn Nadeau.

I’ve recently seen a number of studies like this one reporting limitations in using the National Hydrography Dataset (NHD) for determining headwater streams. The problem seems, to me, less a question of NHD accuracy than one of definition. What, exactly, is a headwater stream? Do you define it based on presence/absence of permanent flow, and how do you define “permanent?” Do you employ a model, like Streamstats? Or, like wetland scientists, do you use habitat criteria? There’s no good answer, but this paper illustrates some of the difficulties.

An accurate account of the extent and flow permanence of headwater streams is critical to estimating downstream contributions. This study 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 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.

[Please note: I have quoted and paraphrased freely from the article, but the interpretation is my own.]

Post-fire runoff

Wednesday, June 19th, 2013

Early View article:Examining Modeling Approaches for the Rainfall-Runoff Process in Wildfire-Affected Watersheds: Using San Dimas Experimental Forest,” by Li Chen, Markus Berli, and Karletta Chief.

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.

Position opening: AE, Water Quality Modeling

Tuesday, June 18th, 2013

AWRA is looking for an Associate Editor for Water Quality Modeling. This position typically handles papers dealing with all kinds of models, both stochastic and deterministic. Many have a multidisciplinary aspect.

JAWRA Associate Editors (AEs) serve as primary advisors to the JAWRA Editor. Responsibilities fall into two areas: reviews and subject development. The AEs for Water Quality Modeling handle about 20-25 papers per year, which would be divided between the two incumbents. All manuscripts are processed through our ScholarOne Manuscripts™ system, with the AE selecting reviewers and, when reviews return, making a recommendation to the Editor. AE’s are encouraged to seek out qualified authors in their subject areas and encourage them to submit papers to JAWRA. These could be individual submittals or as featured collections of related papers organized around an introduction.

Associate editorship is a volunteer position earning our heartfelt thanks and an invitation to our annual AE luncheon. It also offers the opportunity to make a difference on the cutting edge of multidisciplinary water resources. Many AE’s have found the experience of making decisions on manuscripts helpful in sharpening their own professional writing skills. The term of an AE is three years, but may be extended by mutual agreement.

Interested individuals should email their CV to the Editor at editor@awra.org. We are happy to answer any questions. We will hold this position open at a minimum until July 1, 2013.

TMDL balance

Tuesday, June 18th, 2013

Early View article:TMDL Balance: A Model for Coastal Water Pollutant Loadings,” by Stephanie L. Johnson, David R. Maidment, and Mary J. Kirisits

The application highlights an example of distributing bacterial sources spatially based on land use data. The authors developed a TMDL Balance model using 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, they 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.

[Please note: I have quoted and paraphrased freely from the article, but the interpretation is my own.]

AE Xing Fang is stepping down.

Monday, June 17th, 2013

Xing Fang is stepping down as Associate Editor for Water Quality Modeling. Xing has served since 2007, first as AE for Surface Water Hydrology, then moving over to his current position. He’s been a real workhorse for us, always there when we needed him with excellent judgement. Auburn University obviously recognizes his value, because Xing has become very busy with many other tasks in the department, research, and advising graduate students. We will miss him. Please join me in wishing Xing the best as he moves on to greater responsibilities.