EPA Water Research

Sep 22, 2016

Using Green to Combat Saline: Testing Salt-Tolerant Algae as a Desalination Method

EPA Water Research, Safe and Sustainable Water Research 0 Comments

By Christina Burchette

In 2014, the Lawrence Berkeley National Lab Institute for Globally Transformative Technologies released a report called “The 50 most critical scientific & technological breakthroughs required for sustainable global development.” Of all the technologies the report highlighted, the number one priority on the list was a new method for desalinating water. That’s because water security is closely linked with energy and food security issues—world water demand is rising, and more than 70% is used for agriculture.

Algae water sample, desalinated sample, desalinated and filtered water sample

From left: Desalinated and filtered water sample, desalinated water sample, algae water sample

There is a large volume of brackish water (salt water and fresh water mixed together) in many arid areas of the world, but current desalination methods are expensive and use a lot of energy, which means that most people who need them can’t use them. Finding a low-cost and renewable desalination method could help alleviate some of the effects of water scarcity, which is becoming an increasingly apparent problem as we continue to feel the impacts of climate change around the world.

So how do we find a sustainable, low-cost, and energy efficient way to remove salinity from water, making it suitable for drinking and agriculture? By harnessing the power of the ultimate technology: Mother Nature. Recently, some of our scientists investigated the use of salt tolerant algae—also known as halophytic algae—as a natural and sustainable method to decrease salinity in brackish water and seawater. Some species of salt-tolerant algae can absorb up to 50 times more salt than the concentration of salt in the water they inhabit, making them a perfect (and natural!) way to desalinate water for potable use. In addition, the growing algae can be used to mitigate carbon dioxide from point source emissions. Once the algae has been used for desalination, it can then be harvested and used as a raw material for biofuel production to reduce the use of fossil fuels.

The photobioreactor

To gather insight about which algae species would perform the best during experiments, researchers visited an algae bank at the University of Texas at Austin. After screening more than 12 different types of algae species and noting special conditions like pH, micronutrient requirements, and light cycle sensitivity, researchers picked four types of halophytic algae that had the best salt uptake rates.

They then grew and tested the algae for its salt-removal capabilities in a photobioreactor, which is a vessel that housed the algae and provided it with the light it needed to mature. Researchers manipulated the algae’s breeding and feeding conditions to optimize growth rate, survival rate, and absorbency and discovered that they could remove up to 30% salinity in brackish water samples in one treatment stage.

While complete desalination can’t be achieved with algae alone, this method can serve as a pretreatment to other desalination technologies—reducing the energy footprint and financial costs of desalination while making the process more sustainable. EPA researchers are currently comparing the sustainability advantages of biodesalination technology with conventional approaches. This research highlights not only what our researchers are doing to provide potential solutions to global water issues, but also the amazing things that can be achieved with natural resources and a little bit of science.

Various algae species in smaller bioreactors

About the Author: Christina Burchette is an Oak Ridge Associated Universities contractor and writer for the science communication team in EPA’s Office of Research and Development.

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Jul 26, 2016

Intermittent River Ecology: It’s Not a Dry Topic

EPA Water Research, intermittent rivers, river ecology 0 Comments

By Dr. Ken Fritz

Half of the world’s river networks are at least partially intermittent, meaning they have channels that are periodically dry. Due to human activities, perennial rivers (i.e., rivers with year-round continuous flow) are increasingly becoming intermittent. In the past, the scientific field of river ecology has largely focused on perennial systems. However, after years of little attention, the ecological study of intermittent rivers is trending upward.

Intermittent waterways are interesting systems because they are fundamentally transformative in nature. While nearly all waterways expand and contract with pulses of water availability, these changes are particularly noticeable for intermittent waterways. They transition from flowing (even flooding,) to fragmented pools, to completely dry channels. This makes it more of a challenge in predicting patterns and processes compared to rivers which flow year-round. Recognition of the increasing prevalence of intermittent waterways across the globe has spurred greater interest in these systems, particularly in how they function and influence downstream waterbodies.

The difference between a flowing and dry state of an intermittent stream in April (left) and September (right) of the same year. North Fork of Bakers Fork, Wayne National Forest, Ohio (looking upstream)

This intermittent stream is in a flowing state in April (left) and a dry state in September (right). North Fork of Bakers Fork, Wayne National Forest, Ohio, looking upstream.

That’s why the August 2016 special issue of the scientific journal Freshwater Biology focuses on intermittent waterways research. This special issue is titled Intermittent River Ecology as a maturing, multidisciplinary science: Challenges, developments and perspective in intermittent river ecology, and it brings together 13 manuscripts that guide the research and management of this dynamic field of freshwater science. It addresses the most recent intermittent river ecology developments and is freely accessible until August 31^st.

As one of the Guest Editors for this issue, I had the privilege of working with Co-Guest Editors Drs. Thibault Datry (Institue National de Recherche en Sciences et Technologies pour l’Environment et l’Agriculture) and Catherine Leigh (Australian Rivers Institute) who were both funded through the project, Intermittent River Biodiversity Analysis and Synthesis (IRBAS). This special issue is one of the many products on intermittent rivers coming from this group of researchers.

As the special issue testifies, the study of intermittent waterways is not a dry topic but a multifaceted and exciting one. I encourage you to read these articles if you are interested in the ecology and management of systems where stationarity is a myth.

Check out these resources to learn more about EPA research related to intermittent streams:
Headwater Streams Studies
Field manual for determining permanence in headwater streams
Ephemeral streams report
Connectivity report.

About the Author: Dr. Ken Fritz has been a Research Ecologist in EPA’s Office of Research and Development since 2002. He is among the Agency’s leading researchers of intermittent and ephemeral streams.

Jun 23, 2014

Open Science and Cyanobacterial Research at EPA

Application Programming Interfaces, Around the Water Cooler, cyanobacteria, EPA National Lakes Assessment, EPA Water Research, EPA's Environmental Dataset Gateway, harmful algal blooms, microcystin, Open Science, PLOS One, SPARROW model 0 Comments

By: Jeff Hollister, Betty Kreakie, and Bryan Milstead

Algal bloom containing cyanobacteria.

It wasn’t long ago that science always occurred along a well-worn path. Observations led to hypotheses; hypotheses led to data collection; data led to analyses; and analyses led to publications. And along this path, data, hypotheses, and analyses were held close and, more often than not, the only public-facing view of the research was the final publication.

Science has come a long way with this model. However, it was conceived when print was the main media and most scientific questions could be investigated by few scientists over a short period of time.

Then came computers. Then came the internet.

Just like in every other aspect of modern life, these advances are greatly impacting science. It has changed who conducts our science, how we share it, and how others interact with scientific information. All of these changes are playing out through the increasing openness of all parts of the scientific process.

This broad area has been defined as having several components. These components suggest that “open science”:

is transparent (and, of course, open)
includes all parts of research (data, code, etc.)
allows others to repeat the work
should be posted on an open and accessible website (while protecting Personally Identifiable Information, etc.)
occurs along a gradient (i.e. not just a binary open vs. not open)

At EPA, we are learning how to make our research on cyanobacteria and human health (for more info join our webinar) meet those criteria. We are implementing open science in three ways: (1) making our work available via open access publishing; (2) providing access to the code used in our analysis; and (3) making our data openly available.

Several members of our research group have embraced open access options for publishing their research. For instance, our colleague Elizabeth Hilborn and her co-authors published results of their study—examining a group of dialysis patients following exposure to the cyanobacteria toxin microcystin—in one of the pioneering open access journals, PLoS ONE. Also in PLoS ONE, EPA scientist Bryan Milstead and his collaborators published a modeling method to combine the U.S. Geological Survey’s SPARROW model (a modeling tool for interpreting regional water-quality monitoring data), lake depth, lake volume, and EPA National Lakes Assessment data to estimate nutrient concentrations.

As our work progresses, we will continue to choose open access journals. In our experience, this has allowed our research to reach a larger audience and we can more easily track the impact through readership levels using available tools such as PLoS Article Level Metrics.

We are also sharing our data. Currently, this is accomplished through supplements added to publications and through sites such as the EPA’s Environmental Dataset Gateway. We plan to expand these efforts via data publications, version-controlled repositories, and through the development of Application Programming Interfaces (APIs) that provide access to data for developers and other scientists.

The goal of these efforts, and more (stay tuned for a future post on how coding fits in to open science), is to increase the reproducibility of our work (but challenges remain), reach broader audiences, and eventually have a greater impact on our understanding and management of harmful algal blooms.

About the Authors: EPA ecologists Jeff Hollister, Betty Kreakie and Bryan Milstead study greenwater for a living. If you have questions for them, join the webinar on June 25^th or follow the twitter chat on June 26^th using #greenwater.

May 1, 2014

Winning Solutions for Nutrient Pollution

Around the Water Cooler, EPA Water Research, Safe and Sustainable Water 3 Comments

By Dustin Renwick

The partnership for the challenge includes: - White House Office of Science and Technology Policy - U.S. Environmental Protection Agency - U.S. Department of Agriculture - National Oceanic and Atmospheric Administration - U.S. Geological Survey - Tulane University - Everglades Foundation

The partnership for this challenge currently includes:
– White House Office of Science and Technology Policy
– U.S. Environmental Protection Agency
– U.S. Department of Agriculture
– National Oceanic and Atmospheric Administration
– U.S. Geological Survey
– Tulane University
– Everglades Foundation

Nutrient pollution, an excess of nitrogen or phosphorous, costs the country at least $2.2 billion annually. Excess nutrients reaching our waterways spark algae blooms that overpower otherwise healthy ecosystems. In turn, those blooms can contaminate drinking water, kill aquatic species, and create negative impacts for water-based recreation and tourism.

Members of a public-private partnership announced a prize competition in fall 2013 to collect innovative ideas for addressing nutrient overloads. The competition asked innovators to identify next-generation solutions from across the world that could help with reduction, mediation, and elimination of excess nitrogen and phosphorus in water.

Criteria for judging included technical feasibility and accompanying strategic plans for making solutions available and useful. Innovators who met the challenge requirements were each awarded $5,000. They and their winning ideas are:

Aaron Ruesch and Theresa Nelson, with the Bureau of Water Quality in the Wisconsin Department of Natural Resources, proposed combining several data sources into a decision support tool for rapid watershed planning – in some cases, within a day. He used equations to estimate runoff, erosion and soil loss on farms. “All these things together help give us an index of vulnerability,” Ruesch says. The software means local watershed groups can “get the plans out the door quicker to get boots on the ground to implement actual practices.” Ruesch says the money will allow for more outreach and training across the state in the coming year.

David White, president of Ecosystem Services Exchange, proposed a real-time management system that would control water flow and nutrient loading in a field’s tile-drained water. This system would provide quantified evidence of nutrient reductions. “We believe we can reduce nitrogen by 25 to 50 percent,” White says. He is currently discussing a potential test project with officials in Charles City, Iowa. Phase two of White’s solution would pilot a nutrient trading program based on the reductions. “If we can create an asset class for farmers through water quality markets, we can reduce nutrients entering the waterways at a much lower cost.”

Jon Winsten, an agricultural economist and program officer at Winrock International, proposed a pay-for-performance incentive approach, called “model at the farm, measure at the watershed.” Science-based models quantify nutrient losses on individual fields. “Farmers have unique knowledge of their lands,” Winsten says. “By offering a performance-based incentive, then farmers are motivated to find the most appropriate and most cost-effective actions for their specific farms and fields. That’s the most efficient way to get conservation on the ground.” Farmers would receive secondary incentive payments when their entire watershed met reduction goals.

Winners may be part of ongoing discussions by federal and private partners to continue to bring innovative solutions to bear on the problem of excess nutrients in waterways.

About the author: Dustin Renwick works as part of the innovation team in the EPA Office of Research and Development.

Apr 17, 2014

Willingness to Pay for Green Space

Around the Water Cooler, ecosystem services, EPA Water Research, Green Infrastructure, Low Impact Development, property value, stormwater runoff, willingness to pay 3 Comments

By Marguerite Huber

Bike trail through residential green space

How much are you willing to pay for the benefits of low impact development?

Have you ever taken an economics course? If so, you probably studied the concept of “willingness to pay,” or WTP. A person’s willingness to pay for something is the dollar value they have attached to it. For most of us, it’s easy to decide how much we are willing to pay for a car or new home. But what about environmental benefits? EPA researchers are exploring that exact question for green spaces and land development options.

Low impact development (LID) and green infrastructure practices reduce the amount of stormwater running off a particular site. So in places where stormwater runoff has become a significant source of water pollution, the use of these practices has become more necessary. Low impact development benefits and characteristics can include:

improvement in air quality
increased natural areas and wildlife habitat
improved water quality
aesthetic benefits
minimized parking lots and other impervious surfaces
increased access to transit, shared parking, and bicycle facilities

EPA researchers have identified an additional benefit of such practices: increased property values. They and Abt Associates contractors found that property values increase for both new developments and existing properties when located near green spaces associated with low impact development.

The researchers analyzed 35 studies and focused on predicting how much people were willing to pay for small changes in open space. The investigation evaluated the differences in value between open spaces with and without recreational uses.

Results showed that the design and characteristics of a low impact development affects the level of benefits property owners could expect, and that effects on property values declined the farther they are from open spaces. For example, consider a plan that includes a 10% increase in park space or other green space. Property values are projected to increase by 1.23% to 1.95% when located within 250 meters of such a green space, but by 0.56% to 1.2% when located 250-500 meters away. For a homeowner, that could mean a lot of money.

Overall, researchers found that the proximity to and the percent change in open space determined a household’s willingness to pay for low impact open spaces, but it may be site-specific for type of vegetation and recreational use.

Additionally, many states are encouraging developers to use these practices through regulations, incentives, and educational campaigns, so knowing which low impact characteristics maximize the benefits can be useful for policymakers and developers.

You don’t need to have taken an economics course to understand the concept of willingness to pay. It can be applied to the value you place on increased green space and improved water quality. So just how much are you willing to pay for the benefits of low impact development?

About the Author: Marguerite Huber is a Student Contractor with EPA’s Science Communications Team.

Apr 10, 2014

Invaders in the Great Lakes

Around the Water Cooler, ballast water, EPA Water Research, Eurasian ruffe, Great Lakes, Invasive Species, Safe and Sustainable Water, zebra mussels 0 Comments

By Marguerite Huber

Smaller zebra mussels cover a larger native mussel

Zebra mussels cover a native mussel. Image courtesy of U.S. Fish and Wildlife Service

I grew up in Chicago, where Lake Michigan, or simply “the lake” as we locals refer to it, is a part of everyday life. I swam in it. I ran next to it. I drank the water from it. I even paddle boarded on it.

As fond as I am of Lake Michigan, it and all the other Great Lakes are facing a big challenge. They have been invaded by more than 190 species of aquatic plants and animals not native to the area, and at least 22 fishes and 16 aquatic invertebrates pose a high risk of invading the Great Lakes in the near future.

These invasive species can be introduced deliberately or accidentally through ballast water discharge from commercial vessels, recreational boating and fishing, and pet aquarium releases. These species cause significant ecological and economic impacts in the Great Lakes. For instance the cost to the Great Lakes region from invasive species is over $200 million dollars annually!

EPA researchers have been studying how to monitor and detect aquatic invasive species through two different studies in the Duluth-Superior Harbor area, the largest Great Lakes commercial port and one under intense invasive species pressure. A Great Lakes-wide early detection program is required by 2015 under the Great Lakes Water Quality Agreement.

The goal of the research was to evaluate sampling designs that would help develop an efficient early-detection monitoring program for invasive species. To do so, researchers conducted intensive sampling to create a data set that could be used to explore different monitoring strategies.

One study concluded that species detection can be enhanced based on sampling equipment and habitat, making it an important step towards improving early detection monitoring. They found the most efficient strategy was to sample the mix of habitats or gear that produce the most species, but to also sample across all habitats.

In this study, researchers found high occurrences of certain invasive species such as zebra mussel and Eurasian ruffe.

In another study, researchers focused on determining the effort required for early detection of non-native zooplankton, benthic invertebrates, and fish in the Harbor. To do so, the research team tallied and identified roughly 40,000 zooplankton, 52,000 benthic invertebrates, and 70,000 fish during sampling.

In the early detection study, the researchers detected 10 non-native fish species and 21 non-native aquatic invertebrate, some of which were new detections for the Great Lakes. The central finding was that detecting 100% of species is unrealistic given resource limitations, but monitoring at a level that can detect greater than 95% of the species pool is possible. At this level of effort, there is better than a 50% chance of finding a very rare species, such as one that was recently introduced.

Overall, EPA’s invasive species research is yielding a substantial advance in the ability to design monitoring and early warning systems for aquatic invasive species. Together with prevention methods, that should go a long way in maintaining the biological integrity and sustainability of the Great Lakes. That would be welcome news for anyone who relies on “the lake” for their livelihood, their drinking water, or for a place to paddleboard.

About the Author: Marguerite Huber is a Student Contractor with EPA’s Science Communications Team.

Mar 7, 2014

EPA Releases Resource to Help Guide Green Infrastructure

Around the Water Cooler, combined sewer overflows, cso, drinking water, EPA Water Research, Green Infrastructure, municipal sewers, Runoff, Safe and Sustainable Water, stormwater management 1 Comment

By Lahne Mattas-Curry

Rain barrel captures roof runoff in Santa Monica, CA. (Copyright Abby Hall, US EPA)

Imagine you are a municipal sewer system operator in an urban area. You probably would be well aware of the millions of gallons of untreated water that enter your combined sewer systems creating a big old mess in your local water bodies. But what if there was a cost effective solution available? And even better than low-cost, what if the solution made your community pretty and created a great community for people to live, work and play? You would jump on it, right?

Well, many communities with combined sewer overflows have been using green infrastructure – rain barrels, rain gardens, greenways, green roofs etc. – as an attractive way to reduce the stormwater runoff that goes into a sewer system. (We have blogged about it many times before.) Green infrastructure helps reduce capital costs – traditional grey infrastructure made of pipes and other systems is often cost prohibitive – and has been shown to also reduce operational costs at publicly owned treatment works.

EPA scientists helped develop a resource guide to help more communities manage stormwater and wastewater with green infrastructure. The resource, released “Greening CSO Plans: Planning and Modeling Green Infrastructure for Combined Sewer Overflow (CSO) Control (pdf),” will help communities make cost-effective decisions to maximize water quality benefits. The resource explains how to use modeling tools such as EPA’s Stormwater Management Model to optimize different combinations of green and grey infrastructure to reduce both sewer overflow volume and total number of overflow events. The guide also has relevant case studies to showcase how different communities are using green infrastructure.

Hopefully using this resource can help you plan green infrastructure solutions and provide a variety of tools that can help you measure and reduce stormwater runoff.

For more information about green infrastructure at EPA, please visit: http://water.epa.gov/infrastructure/greeninfrastructure/index.cfm

You can also learn more about green infrastructure research and science here:

http://www2.epa.gov/water-research/green-infrastructure-research

About the author: Lahne Mattas-Curry works with EPA’s Safe and Sustainable Water Resources team, drinks a lot of water and communicates water research to anyone who will listen.

Feb 6, 2014

Researching and Restoring the Gulf

Around the Water Cooler, BP oil spill, EPA Water Research, Gulf of Mexico, Gulf of Mexico dead zone, Hypoxia, Safe and Sustainable Water 4 Comments

By Marguerite Huber

Hypoxia sounds like some sort of deadly disease. While it is not a disease, it is in fact deadly. Also referred to as dead zones, hypoxic water kills bottom-dwelling marine life such as crabs and mussels. (To learn more, see the video at the end of this blog.)

Dead zones lack dissolved oxygen and are caused primarily by excess nutrients such as nitrogen and phosphorous. Too many nutrients cause algae and plankton to grow in large numbers, and as the algae die and decompose, oxygen is consumed.

Excess nutrients are especially a problem in the Gulf of Mexico. Every summer, nutrient-rich freshwater from the Mississippi River flows into the Gulf, resulting in a dead zone of about 7,772 sq. mi. that causes massive fish kills and chases other creatures further out to sea.

In an effort to understand this annual occurrence, EPA researchers have developed a modeling framework for predicting how nutrient management decisions and future climate change scenarios will impact the size, frequency, and duration of hypoxic conditions that form in the Gulf of Mexico every summer.

Providing 17% of the Nation’s gross domestic product, the natural resources of the Gulf’s coastal and marine habitats and their ecosystem services are critical to both the regional and national economy. That’s a major reason why EPA researchers are exploring ways to improve and restore Gulf water quality and aquatic habitats.

Since the 1990’s, the Agency and its partners from coastal states have been monitoring estuaries and most recently, wetlands. This baseline came in handy in the aftermath of Hurricane Katrina and the BP oil spill, and it will continue to help researchers track the degree of recovery resulting from ongoing and future restoration actions in the Gulf.

Monitoring in the future will also help inform environmental management decisions by addressing linkages between ecosystem condition and the goods and services provided. Agency researchers have several methodologies in development for examining these linkages, including spatial analysis tools, and human well-being indices.

About the Author: Marguerite Huber is a Student Contractor with EPA’s Science Communications Team.

Jan 22, 2014

Braving the Weather to Promote Green Infrastructure in Philadelphia

Around the Water Cooler, EPA Connect, EPA Water Research, Green Infrastructure, Science to Achieve Results (STAR), star 0 Comments

Reposted from “EPA Connect, the official blog of EPA’s leadership“

CEQ Chair and EPA Deputy Administrator brave the snow.

Council on Environmental Quality Chair Nancy Sutley and EPA Deputy Administrator Bob Perciasepe brave the snow in Philadelphia.

By Bob Perciasepe

Yesterday, I was up in Philadelphia joined by CEQ Chair Nancy Sutley and Mayor Nutter to announce nearly $5 million in EPA grants made possible through the Science to Achieve Results (STAR) program. These investments are going to five universities, and aim to fill gaps in research evaluating the costs and benefits of certain green infrastructure practices.

The projects to be invested in, led by Temple University, Villanova University, Swarthmore College, University of Pennsylvania and University of New Hampshire, will explore the financial and social costs and benefits associated with green infrastructure as a stormwater and wet weather pollution management tool.

Street Trees: More than Meets the Eye

Around the Water Cooler, ecosystem services, EPA Water Research, Green Infrastructure, i-Tree, street trees, sustainability, Tree City USA, trees, USDA Forest Service 3 Comments

By Marguerite Huber

There is more to street trees than meets the eye.

Ever since I took an urban forestry course in graduate school, I can’t help but always look at trees. I look at their bark, their roots, and their leaves. But when I look at trees, I am not just seeing their physical attributes. I also see all the conceptual benefits they provide to our communities.

Trees are not just a pretty fixture in your backyard. They provide many ecosystem services to our cities and towns, including: improving air quality, absorbing and storing carbon, supplying privacy, reducing noise, increasing property value, and decreasing building energy use. Trees are an important aspect of the green infrastructure that helps reduce storm water flow.

Amazingly, you don’t have to be an arborist to calculate tree benefits; you can use i-Tree, a USDA Forest Service model that uses sampling data to estimate street tree benefits.

In the fall of 2013, EPA scientists began research on “street trees” (trees growing in the public right-of-way, usually in between the street and the sidewalk) in nine communities in the Cincinnati, Ohio metropolitan area. The randomly selected communities all differ in geographic setting, socioeconomic characteristics, and street tree management practices.

Their research aims to answer such questions as: Can street tree structure and benefits be explained by management practices, socioeconomic conditions, or historical or geographic factors? How might invasive pests affect street trees and their benefits? How will existing street tree structure and benefits change in the future under various scenarios of tree growth and mortality, management practices, and pest outbreaks?

Researchers sampled more than 53 miles of street right-of-way along more than 600 street segments and inventoried nearly 3,000 trees. The street tree benefits were estimated using i-Tree Streets.

At this time researchers are still analyzing street tree benefits and their relation to community characteristics such as management practices, socioeconomics, and geographic setting. So far they have found management practices to be particularly important, with Tree City USA participants gaining greater benefits than communities that do not participate. Since analyses are still continuing, the findings on the other community characteristics will be released in the coming months.

When the project is completed, the researchers will have deliverables such as street tree inventory data that can be shared with community officials and an understanding of which community characteristics influence street tree structure and ecosystem services.

I invite you to check out i-Tree for yourself; I suspect as you’ll realize there are more to street trees than meets the eye.

About the Author: Marguerite Huber is a Student Contractor with EPA’s Science Communications Team.

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