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The Arkansas Water Resources Center publishes this e-newsletter each month to highlight research, faculty, news and important events.
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Arkansas Water Resources Center
Newsletter - March 2015
Study Released Evaluating the 
Chlorophyll-a Criteria for Beaver 
Lake, Arkansas
 
The University of Arkansas Division  of Agriculture and the Arkansas Water  Resources Center completed a report  that evaluated how to assess whether  Beaver Lake in northwest Arkansas was meeting the water quality criteria for chlorophyll-a (the amount of algae in the water) and Secchi transparency (a measure of how clear the water is). The project was commissioned by the Beaver Watershed Alliance, representing many stakeholders in the watersheds including Washington County Farm Bureau, CH2MHILL, City of Fayetteville, Tyson Foods Inc. and Beaver Water District among others.
 
Beaver Lake is the major municipal water supply for northwest Arkansas and is the only water body in Arkansas that has numeric water quality standards for chlorophyll-a and Secchi transparency. The standard for chlorophyll-a was set at 8 µg/L for the geometric mean (a type of average that lessens the impact of really high or low values) during the growing season (May through October) and for Secchi transparency at 1.1 m for the annual average at Hickory Creek, just downstream of the confluence of War Eagle Creek with the White River. These standards were adopted in 2012 in response to the recommendations of a working group that conducted a multi-tiered scientific analysis of the data available at Beaver Lake prior to 2008. However, the way the standards were going to be evaluated was not defined during development - specifically about allowing flexibility in defining how many times the criteria could be exceeded within a certain number of years. 

The new study was conducted to suggest options on how the Arkansas Department of Environmental Quality might determine if Beaver Lake was exceeding the numeric criteria for chlorophyll-a and Secchi transparency. Through the analyses of long-term water quality data at various sample sites in Beaver Lake, the suggestions included the following: 1) the minimum number of exceedances that trigger a water-quality violation should be greater than one-half the number of years in the assessment period; 2) consider a long-term assessment period; 3) consider coupling the standards for chlorophyll-a and Secchi transparency; and 4) consider revising the location where the standards are evaluated.  The report suggested that the numeric criteria were developed based on average conditions, and that any assessment of the water quality standards must consider this. Regulatory agencies can use the scientific findings and recommendations in the report to guide decisions regarding the evaluation of the numeric criteria for Beaver Lake. The entire report can be accessed here.
Researcher Spotlight on Connie Moloney and Dr. Wen Zhang 
Graduate Student and Assistant Professor, Department of Civil Engineering 
              
Last year, Moloney  and Zhang received a  base grant from the AWRC  through the US Geological Survey 104B program to fund a research project titled “Microbial Community Under the Changing Pre-Oxidation Regime at Beaver Water District”. 
 
The Problem: Drinking water treatment plants (DWTPs) often use free chlorine (Cl2) as a disinfectant. Chlorine oxidizes organic matter like algae and bacteria, but can result in the formation of disinfection by-products (DBPs). DBPs can be harmful to human health and as such are regulated by the US Environmental Protection Agency as part of the Safe Drinking Water Act. Many DWTPs, including Beaver Water District, are switching to chlorine dioxide (ClO2) due to its reduction in DBP formation, but its use as an oxidant and its impact on water treatment processes is not fully understood.
 
So What?: DWTPs must use enough disinfectant to kill bacteria and other organisms of concern but not too much in order to keep DBP formation low due to drinking water regulations and human health concerns. Chlorine dioxide is an effective disinfectant, can reduce the amount of DBPs formed and can control taste and odor problems. But, the use of chlorine dioxide is still relatively new and should be studied in order to ensure that DWTPs continue to provide safe, high quality drinking water to the public.
 
The Research Question: Changing disinfectants from free chlorine to chlorine dioxide can result in shifts in the bacterial community within the treatment plant. Moloney and Zhang wanted to identify the diversity of bacterial taxa (specific groups of bacteria) that persisted within the facility during the shift from free chlorine to chlorine dioxide use.
 
The Methods: Beaver Water District switched its primary disinfectant between chlorine and chlorine dioxide in the summer of 2013. Moloney and Zhang grew bacteria on artificial substrate in the sedimentation basins within the DWTP. They also collected water samples from the DWTP intake to study the bacterial community and other water quality parameters such as total organic carbon and nutrient concentrations. Bacteria were identified and enumerated using molecular techniques and high powered microscopy.  Bacterial diversity changes were then correlated with free chlorine or chlorine dioxide treatments.
 
The Benefits: As DWTPs change from free chlorine to chlorine dioxide, the shift in microbial community structure can influence disinfection efficacy and DBP formation. Moloney and Zhang’s research can help to understand these shifts in microbial communities and identify possible DBP precursors within the facility. Plant managers can use this information to guide disinfection activities to ensure continued production of high quality drinking water.
Spotlight on 
Arkansas Department of Health

The Engineering Section of the Arkansas Department of Health (ADH) is responsible for 
overseeing public water systems throughout the state to ensure the distribution of safe, palatable water for public use. Every state is required by the US Environmental Protection Agency to develop a Source Water Assessment Program (SWAP) and the ADH is in charge of that in Arkansas.
 
ADH is creating an updated SWAP model that utilizes GIS (geographic information system) and geoprocessing to integrate multiple layers of watershed information to create thorough assessments of surface source water supplies. This process includes gathering information about soil types, geology, precipitation, and other factors that might influence how pollutants move through a watershed, as well as assessing where industrial and municipal wastewater discharges exist and how vulnerable the watershed is to contamination. These data are then used to create a vulnerability assessment and to identify hot spots where the chance of polluting a source water is high.
 
The ADH is currently beta testing and adjusting the revised SWAP model. Upon completion, the SWAP model will establish a multi-faceted approach to help manage drinking water supplies and watersheds throughout Arkansas. This program can be used by water resource managers and organizations to identify possible needed infrastructure upgrades and best management practices that can help to ensure continued safe drinking water supplies for Arkansas residents. 
17th Annual EPA Region 6 Stormwater Conference
 
The US Environmental Protection Agency Region 6 is hosting its 17th Annual Stormwater Conference on October 18-23, 2015 in Hot Springs, AR. This year’s conference will address the various issues and challenges of managing municipal storm water and upcoming rules and regulations.
 
Conference topics will include stormwater management programs, sustainability, green infrastructure and low impact development, TMDL’s and watershed protection, best management practices case studies, construction and industrial stormwater management, and advanced topics and new technologies.
 
The deadline for presenters to submit abstracts is April 10, 2015. Click here for more information.
Upcoming Events

March 14, 2015
Streamside Planting 
Beaver Lake Watershed


March 21, 2015
War Eagle Creek Cleanup
War Eagle Mill, Rogers

Devil's Eyebrow Reforestation Workday
Devil's Eyebrow Natural Area

March 26-27, 2015
2015 Oklahoma Student Water Conference 
Oklahoma State University 

April 8-9, 2015
Oklahoma Clean Lakes and Watersheds Association 24th Annual Conference 
Stillwater, Oklahoma

April 25, 2015
East Fork Cleanup 
Bunch Park, Elkins

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   Chemist

Garver
   Project Engineer

     Frisco, TX
   Summer Intern
     North Little Rock, AR

   Summer Intern
     Tulsa, OK


Arkansas Natural Resources Commission
   Engineer
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