Archive for July, 2010

Forest Roads

Wednesday, July 28th, 2010

August 2010 Article: Forest Road Erosion Control Using Multiobjective Optimization, by Matthew Thompson, John Sessions, Kevin Boston, Arne Skaugset, and David Tomberlin.

Graph showing example of an efficient frontier.

Efficient frontier (Figure 3 from article.)

Controlling road-related erosion remains an important issue for forest stewardship. This article uses mathematical programming techniques to identify the efficient frontier between sediment reduction and treatment costs. Information on the nature of the tradeoffs between conflicting objectives can give the decision maker more insight into the problem, and help in reaching a suitable compromise solution.

Optimization methods involve algorithms that make some folks’ eyes glaze over, but to me they are really cool stuff with lots of practical use. What this paper looks at is how to get any degree of sediment reduction for the least amount of cost. Those dots on the right in the example are all inefficient solutions. Move left to the line and you’ll always find a better deal for sediment reduction.

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

Residential Soil Disturbance

Monday, July 26th, 2010

August 2010 Article: Impact of Residential Soil Disturbance on Infiltration Rate and Stormwater Runoff, by Christopher J. Woltemade.

Digging into my old yard in Reston always was an adventure: I never knew what I’d find  – bricks, lumber, etc. — left over from my home’s construction in 1967. Construction practices clearly left something to be desired. This study in southern Pennsylvania confirms my own unscientific observation of a huge amount of variation in how residential lawns respond to precipitation.

Curve numbers and stormwater runoff were substantially higher for lots constructed post-2000 compared with lots built pre-2000 and for undisturbed soils, documenting the magnitude of possible error in stormwater runoff models that neglect soil disturbance. A failure to consider such soil disturbances may lead to substantial errors of under-prediction in rainfall-runoff models.

The solution ultimately comes down to local codes and practices: Limit the footprint of soil disturbance, using mechanical soil loosening and organic soil amendments at the time of construction, and apply long-term lawn and landscape maintenance to enhance infiltration.

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

Wiley Online Library

Friday, July 23rd, 2010

Online access to JAWRA will be changing — for the better! — very shortly. Our Wiley-Blackwell partners have advised us Wiley Online Library will be launched over the weekend of 7–8 August 2010. It will completely replace Wiley InterScience.

Wiley InterScience [the current online view of JAWRA] will no longer be available from Saturday 7 August at 4am Eastern Daylight Time, 9am British Summer Time, 4pm Singapore Standard Time.  Wiley Online Library is due to go live on Sunday 8 August at 12pm Eastern Daylight Time, 5pm British Summer Time, Monday 9 August 12am Singapore Standard Time. During this transition period, users will see a message explaining the reason for the unavailability and will be directed to www.wileyonlinelibrary.com/info for more details. Once Wiley Online Library is live, you will be able to access JAWRA content and visit the new JAWRA home page.

Meanwhile for more information please visit the Wiley Online Library Information Website.

Indices of Physical Habitat

Wednesday, July 21st, 2010

August 2010 Article: An Evaluation of Qualitative Indexes of Physical Habitat Applied to Agricultural Streams in Ten U.S. States, by Robert M. Hughes, Alan T. Herlihy, and Philip R. Kaufmann

The diversity of metrics and methods for assessing physical habitat condition confounds comparisons among practitioners. Rapid qualitative indicators and assessments typically have higher sampling error and unknown bias, but time-intensive indicators limit the number of sites that can be sampled, all else being equal. This article presents a comparison of several popular indexes and concludes with some interesting observations on the roles of indexes and the need for more research.

The authors surveyed 51 previously sampled stream sites located in regions of row-crop agriculture in Oregon, California, North Dakota, South Dakota, Nebraska, Iowa, Minnesota, Pennsylvania, Maryland, and West Virginia to evaluate the comparability of four indexes of physical habitat condition relative to each other. The four indexes were: rapid bioassessment protocol (RBP); qualitative habitat evaluation index (QHEI); stream visual assessment protocol (SVAP); and qualitative physical habitat index (QTPH).

Their conclusion: “Despite varying perspectives of what ‘’habitat’’ is and the use of different metrics, these four qualitative physical habitat assessment protocols produced similar results. This suggests that if the goal is a rough estimate of overall physical habitat quality, the three wholly qualitative protocols are just as adequate as one based on multiple quantitative measurements of physical habitat (QTPH), which requires much more field effort. However, the highly significant correlations between macroinvertebrate biotic index scores and quantitative substrate metrics suggest that quantitative physical habitat measures may offer greater explanatory power than qualitative habitat assessments.” You’ll want to read the whole article before acting on this, because there obviously are a lot of qualifications.

The authors also note that protocols, indexes, and scoring criteria to suit natural regional and local differences and differing professional perspectives and management objectives hinder making national or regional assessments of stream habitat conditions in a consistent manner.

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

Water User Associations in China

Tuesday, July 20th, 2010

August 2010 ArticleWater Governance and Water Use Efficiency: The Five Principles of WUA Management and Performance in China, by Jinxia Wang, Jikun Huang, Lijuan Zhang, Qiuqiong Huang, and Scott Rozelle.

The overall goal of this paper is to better understand the emergence of water user associations (WUAs) in China and assess if they are adhering to the practices spelled out by the Five Principles, a set of recommended practices that are supposed to lead to successful WUA operation. Using four sets of different types of villages to examine implementation and performance, the authors found that World Bank-supported WUA villages (‘‘Bank villages’’) can be thought of as operating mostly according to the Five Principles. For example, the Bank villages were endowed with a more reliable water supply; were set up and were operating with a relatively high degree of farmer participation; and leaders were more consultative and the process more formal.

Good intentions and good theory do not automatically make for a successful development strategy. The “Five Principles” — reliable water supply, legal status and participation, hydrologic boundaries, measured deliveries, equitable charges — are theoretically good ideas. The authors note, however, “Surprisingly, given the high profile that the World Bank’s WUA projects have assumed, in fact, there has never been a rigorous evaluation conducted by an independent research team.” I liked this paper because it holds theoretically good ideas up to the cold hard light of facts. In this case, the authors found applying these principles really did lead to better outcomes. Better late than never, I suppose.

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

SPARROW Model for Chesapeake Bay

Friday, July 16th, 2010

August 2010 article: Sources of Suspended-Sediment Flux in Streams of the Chesapeake Bay Watershed: A Regional Application of the SPARROW Model, by John W. Brakebill, Scott W. Ator, and Gregory E. Schwarz

Chesapeake Bay loadings

The authors applied SPAtially Referenced Regressions on Watershed  attributes (SPARROW), which spatially correlates estimated mean annual flux of suspended sediment in nontidal streams with sources of suspended sediment and transport factors. According to their model, urban development generates on average the greatest amount of suspended sediment per unit area, although agriculture is much more widespread and is the greatest overall source of suspended sediment.

How do we effectively combat sedimentation? The authors conclude applying erosion and sediment controls from agriculture and urban development in areas of the northern Piedmont close to the upper Bay, where the combined effects of watershed characteristics on sediment transport have the greatest influence may be most helpful in mitigating sedimentation in the bay and its tributaries.

This is easier said than done. The Chesapeake Bay drainage comprises parts of six states plus the District of Columbia. In today’s divisive political climate, getting all the actors to agree on anything would be a miracle. But, the evidence is accumulating that the problem is more than urban in character.

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

Satellite Tracking of Cholera

Thursday, July 15th, 2010

August 2010 Article: Tracking Cholera in Coastal Regions Using Satellite Observations, by Antarpreet S. Jutla, Ali S. Akanda, and Shafiqul Islam.

Chlorophyll in the Bay of Bengal

Our Featured Series on Satellite Hydrology concludes with an article in which Antarpreet S. Jutla et al. investigate relationships between cholera incidence and coastal processes and explore the utility of using remote sensing data to track coastal plankton blooms, using chlorophyll as a surrogate variable for plankton abundance, and subsequent cholera outbreaks.

Though satellites are not necessarily a good substitute traditional hydrologic data, they can be invaluable where politics or logistics prevent collecting or sharing on-the-ground observations. Moreover, the large areas observable can provide an important complement to sparse terrestrial or oceanic observations.

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