Archive for September, 2012

Sediment Source Fingerprinting

Monday, September 24th, 2012

Early View article:Sediment Source Fingerprinting: Transforming From a Research Tool to a Management Tool,” by Rajith Mukundan, Desmond E. Walling, Allen C. Gellis, Michael C. Slattery, and David E. Radcliffe

I will let a good abstract, below, speak for this article. It calls attention to the maturing of an important technique.

“Information on the nature and relative contribution of different watershed sediment sources is recognized as a key requirement in the design and implementation of targeted management strategies for sediment control. A direct method of assessing sediment sources in a watershed that has attracted attention in recent years is sediment fingerprinting. The aim of this article is to describe the development of sediment fingerprinting as a research tool and to consider how the method might be transformed from a research tool to a management tool within a regulatory framework, with special reference to the United States total maximum daily load (TMDL) program. When compared with the current source assessment tools in developing sediment TMDLs, sediment fingerprinting offers considerable improvement as a tool for quantifying sources of sediment in terms of source type (e.g., channel vs. hillslope) as well as spatial location (subwatershed). While developing a conceptual framework for sediment TMDLs, we recognize sediment fingerprinting along with sediment budgeting and modeling as valuable tools in the TMDL process for developing justifiable sediment TMDLs. The discussions presented in this article may be considered as a first step toward streamlining the sediment fingerprinting approach for its wider application in a regulatory framework.”

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

Back in the USA

Wednesday, September 19th, 2012

Hopped across the Pond yesterday, dodging the storms, and today will be dedicated to putting our household back in order. I’ve scheduled serious time tomorrow and Friday for catching up on manuscripts.

England was wonderful! Despite one of the wettest summers in history, London’s sky for our visit was clear and sunny. London was a real treat, a true cosmopolitan city comparable only to New York. Our sightseeing took us many times along and across the Thames, and I gained a new appreciation of how important that river — actually, an estuary with strong tides – was and is to the city on its banks.

Sir Isaac NewtonMuch of our science today traces its beginnings to England. In the photo at right, I’m standing next to a bust of Sir Isaac Newton in Kensington Palace. This is the room where he explained his theory of gravity to the King. Fortunately, Charles II didn’t dismiss gravity as “only a theory,” and Newtonian physics eventually got us to the moon.

Greetings from the UK

Tuesday, September 11th, 2012

This blog’s been a little quiet because Kathy and I are visiting our daughter in London. We get to spend time with Sara and her husband AND tour a great city. Such a deal!

As you can tell, I have internet access. Time to work is another matter altogether! I will handle the most urgent matters and save the rest until our return next week. Meanwhile… I have to go down the street and walk a couple of corgis for a nice old lady.

Bioretention design

Wednesday, September 5th, 2012

Early View Article: “Bioretention Design for Xeric Climates Based on Ecological Principles,” by C. Dasch Houdeshel, Christine A. Pomeroy, and Kevin R. Hultine.

Bioretention as sustainable urban stormwater management has gathered much recent attention, and implementation is expanding in mesic locations that receive more than 1,000 mm of annual precipitation. The arid southwestern United States is the fastest growing and most urbanized region in the country. Consequently, there is a need to establish design recommendations for bioretention to control stormwater from expanding urban development in this ecologically sensitive region. This article reviews the ecological limits and opportunities for designing bioretention in arid and semiarid regions.

The survey of bioretention, plant physiology, and wildland restoration supported by leaf gas exchange measurements and hydrologic modeling exercises presented here suggest that if bioretention system design is ecologically based, then bioretention can be utilized to mitigate negative effects of urban stormwater runoff and reduce per-capita water demand by providing a zero-irrigation alternative to traditional landscaping. Addressing both stormwater runoff and easing demand for regional water resources will benefit the fragile desert ecosystems that surround the fastest growing population centers in the country.

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

Geomorphic-Ecological Relationships

Wednesday, September 5th, 2012

Early View Article: Geomorphic-Ecological Relationships Highly Variable between Headwater and Network Mountain Streams of Northern Idaho, United States,” by S. Mažeika P. Sullivan.

In this study, multiple geomorphic characteristics were correlated with descriptors of macroinvertebrate and fish assemblages in both headwater and network streams. The current study provides initial evidence that geomorphic-ecological relationships are markedly different in headwaters than in their downstream counterparts. Differences between headwater and network streams were observed relative to both the strength of geomorphic-biotic relationships as well as to their specific nature. Overall, the data supported the expectation that macroinvertebrate assemblages would be more tightly linked to geomorphic characteristics in headwater streams, but did not support the expectation that fish-geomorphic relationships would dominate in network streams. Ultimately, understanding differences in geomorphic-fish relationships between headwater and network streams will require considering the mobility and life-histories at the species level. Many fish that spend the majority of their lives in larger streams and rivers use headwater streams for spawning and nursery areas.

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

SWAT and snowmelt

Wednesday, September 5th, 2012

Early View Article:A Simple Process-Based Snowmelt Routine to Model Spatially Distributed Snow Depth and Snowmelt in the SWAT Model,” by Daniel R. Fuka, Zachary M. Easton, Erin S. Brooks, Jan Boll, Tammo S. Steenhuis, and M. Todd Walter.

Another neat routine for the SWAT model…

The authors present a method to integrate a process-based snowmelt model that requires only daily temperature and elevation information into the Soil and Water Assessment Tool (SWAT) model. The model predicts the spatiotemporal snowpack distribution without adding additional complexity, and in fact reduces the number of calibrated parameters.

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

Rainfall variability

Tuesday, September 4th, 2012

Early View Article:Physically Based, Hydrologic Model Results Based on Three Precipitation Products,” by Singaiah Chintalapudi, Hatim O. Sharif, Subash Yeggina, and Almoutaz Elhassan.

More on the question of how to measure spatial and temporal variations in precipitation…

The main objective of the study is to examine the accuracy of and differences among simulated streamflows driven by rainfall estimates from a network of 22 rain gauges spread over a 2,170 km2 watershed, NEXRAD Stage III radar data, and Tropical Rainfall Measuring Mission (TRMM) 3B42 satellite data. The Gridded Surface Subsurface Hydrologic Analysis (GSSHA), a physically based, distributed parameter, grid-structured, hydrologic model, was used to simulate the June-2002 flooding event in the Upper Guadalupe River watershed in south central Texas. There were significant differences between the rainfall fields estimated by the three types of measurement technologies. These differences resulted in even larger differences in the simulated hydrologic response of the watershed. In general, simulations driven by radar rainfall yielded better results than those driven by satellite or rain-gauge estimates.

The model simulation results driven by NEXRAD Stage III estimates compared well with the USGS observed flows over a 2,170 km2 watershed at a 15-min time scale. The model simulation results driven by gauge-observed precipitation data estimates severely underestimated the peak flow and runoff volumes for the event. The TRMM simulated results underestimated the peak discharge for some peaks and overestimated the other peaks and overestimated the total runoff volume.

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

Bridges and barriers

Tuesday, September 4th, 2012

Early View Article:Adaptation Bridges and Barriers in Water Planning and Management: Insight from Recent Extreme Droughts in Arizona and Georgia,” by Nathan L. Engle.

Why do some planning efforts succeed and other fail? Here’s another article which sheds some light on that question. This article evaluates this ability, or adaptive capacity, within large urban community water systems in Arizona and Georgia. It analyzes interview data on the bridges and barriers to adapting water management approaches in relation to extreme droughts over the past decade.

This study shows that learning and education, information, knowledge exchange, and research are critical bridges for adaptation. In Arizona, these bridges prove beneficial as either formal or informal collaborations/exchanges. In Georgia, professional organizations present platforms for enabling quick information exchange and collaboration, but regulation seems to be an equally important force in establishing the necessary institutional channels. However, regulation presents itself as a double-edged sword, in that it can withhold systems from taking more drastic or progressive actions within their local purview that might further increase adaptive capacity.

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

Streamflow trends in the southeastern US

Monday, September 3rd, 2012

Early View Article:Streamflow Changes in the South Atlantic, United States During the Mid- and Late 20th Century,” by Lauren A. Patterson, Brian Lutz, and Martin W. Doyle.

Thirty-five years doesn’t prove a climate trend, but this article certainly is timely given the 2012 summer. The authors examined the monthly and annual trends of streamflow, precipitation, and temperature in the South Atlantic for the time periods: 1934-2005, 1934-1969, and 1970-2005.You will need to read the full article to see all the findings, but some of the key findings are below

Streamflow and climate (temperature and precipitation) trends transitioned ca. 1970. From 1934 to 1969, streamflow and precipitation increased in southern regions and decreased in northern regions; temperature decreased throughout the South Atlantic. From 1970 to 2005, streamflow decreased, precipitation decreased, and temperature increased throughout the South Atlantic.

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