February 2013, Vol. 25, No.2
Professionals share knowledge to prepare for extreme weather and climate events
As extreme weather and climate events
become more common, the ability of water resource managers and water service
providers to respond is challenged, and the potential increases that these
events will disrupt stormwater control and wastewater conveyance and treatment.
To protect against
this, water-sector professionals are sharing their experiences. An effort that
will culminate this year in a research report began in August 2010 with a 2-day
workshop. More than 80 drinking-water-sector professionals met to discuss their
weather-related information needs for making key decisions on investments.
participants were concerned about risks, vulnerabilities, preparation, and
adaptation strategies associated with an increase in the number and intensity of
extreme weather events,” said Lauren Fillmore, Water Environment Research
Foundation (WERF; Alexandria, Va.) senior program manager. Many noted that they
knew colleagues who had faced such events recently and recognized the need to
exchange knowledge gained to better prepare, she added.
As a result of the
workshop, the U.S. National Oceanic and Atmospheric Administration and the U.S.
Environmental Protection Agency agreed to collaborate with water research
organizations, including WERF and the Water Research Foundation (Denver), to
document experiences and synthesize collective knowledge. As the project moved
forward, other research organizations, such as Concurrent Technologies Corp.
(Stafford, Va.) and Noblis (Falls Church, Va.), joined the effort.
research project examines how water utilities, resource managers, and county
and regional planners make decisions before and during extreme weather, and how
they have adapted and expect in the future to adapt planning efforts to better
prepare. When complete, the project will identify how scientific data were
used, what information gaps exist, and what information is needed to improve
water utilities’ ability to adapt and respond to recurring events.
organizations currently are hosting six workshops across the United States. The
workshops are organized by type of extreme event — drought, heavy rain and
flooding, sea-level rise and storm surges, and extreme temperatures — and will
be complete by late spring, Fillmore said.
The research team is
compiling case studies documenting the workshop findings, including lessons
learned and information needed by water service providers so that both
utilities and communities are able to make better decisions in the future,
Fillmore said. These case studies will address
experienced while responding to extreme event conditions;
technologies, tools, information, services, and other approaches that were
conducted before and during these events;
that were in place and used when responding to events;
made, who made them, under what conditions, and how successful they were at
coping with the events;
economic, and ecological effects;
on water resources; and
in planning, implementation, approaches, capital improvements, collaboration,
communication, and decision-making that resulted.
For more information,
read the WERF report The Future of Research on Climate Change Impacts on
Water at http://goo.gl/Wu8xr.
Determining how to optimize the Phosphorus Index
The Phosphorus Index was designed in
1992 to help farmers identify appropriate management practice for phosphorus
application, depending on different soil and environmental conditions,
according to an American Society of Agronomy (
) news release. It
was meant to be easily computed from readily available data, but because many
factors influence phosphorus loss, different regions and states were left to
develop their own versions. Today, there are 48 different versions, according
to Nathan Nelson, an American Society of Agronomy member and co-author of a
paper in the Journal of Environmental Quality that introduces a special
section on the Phosphorus Index.
“The challenge now is
to develop consistency in phosphorus indices across state boundaries and
quantify the accuracy of phosphorus index risk assessments,” Nelson said in the
Phosphorus Index was developed to assess the risk of phosphorus leaving a site,
create a method to identify parameters influencing phosphorus loss, and select
management practices to decrease vulnerability to phosphorus loss, the news
release says. Factors include how much phosphorus is in the soil, rates of
phosphorus fertilization, methods or timing of phosphorus addition, and
phosphorus transportation factors, such as erosion, runoff, and distance to
The special section
(“Evaluation of Phosphorus Indices after Twenty Years of Science and
Development”) published in the Journal of Environmental Quality includes
a collection of papers assessing the effectiveness of the Phosphorus Index.
acknowledges the problems that have been encountered with P[
development and implementation … and also suggests ways in which the indices
can be tested against data or models to improve risk assessment and shape
future indices,” the news release says.
The seven papers in the collection “conclude that [
indices can provide accurate assessments of [
loss, but must be evaluated appropriately,” according
to the section’s introductory paper. Evaluation requires compiling regional
data sets on small-watershed scales.
papers also conclude that simulation models can generate
estimates if they are calibrated and validated to ensure accuracy, the paper
says. “Further development of [
indices will require
coordinated regional efforts to identify common P[hosphorus] Index frameworks
and standardized interpretations,” the paper says.
Find the special section at
DARIES model predicts efficiency of anaerobic technology
potential for anaerobic technology to recover resources and reduce costs can be
an important tool for U.S. dairy farms interested in using manure waste as a
nutrient and energy resource. Researchers from the Clarkson University
Institute for a Sustainable Environment presented the Dynamic Anaerobic Reactor
and Integrated Energy System (DARIES) model as a prediction tool in the
December 2012 issue of Water Environment Research (WER).
technology has the potential to recover biogas, reduce odors and pathogens, and
manage nutrients, but often has high capital and operating costs, the WER
article says. Modeling the potential for this technology to benefit farm
operations would prove a useful tool.
DARIES is a dynamic
system that uses hourly weather data to calculate heat losses and digester
temperature, which affects biokinetic transformations and biogas production.
The model can be used in a completely mixed or plug-flow reactor configuration
and predicts biogas production and composition as well as electricity
production, the article says.
researchers looked at the DARIES model’s ability to predict biogas and
electricity production and to identify operational and design parameters that
have the greatest effect on model output. They compared the model’s predictions
to recorded data for 18 full-scale dairy digesters in the northeastern United
States as well as results from the U.S. AgSTAR model FarmWare 3.4, the article
that DARIES was an accurate model for biogas, methane, and electricity
production predictions. The model predicted biogas accurately, underpredicted
methane by 12% on average, and predicted electricity production within an
expected range of variation, the article says. The researchers concluded that
the model is more accurate than the “overly optimistic” FarmWare model that
over-predicted both biogas and methane by 20% to more than 50%, the article
determined that DARIES output was most sensitive to influent flow rate,
chemical oxygen demand, and biodegradability, and somewhat sensitive to
hydraulic retention time and digester temperature, the article says.
The article, “The
Dynamic Anaerobic Reactor & Integrated Energy System (DARIES) Model: Model
Development, Validation, and Sensitivity Analysis,” appears in the December
2012 issue of Water Environment Research and can be downloaded free at http://goo.gl/ZQzmD.
Environment Research allows open access to one article per issue on a range
of important technical issues such as nutrient removal, stormwater, and