Concurrent Session 5

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8:00 am – 9:15 am
CONCURRENT SESSION 5
Salon A Salon B Windsor Ballroom
Session Title Stream Corridor Restoration II Lake & Reservoir Water Quality Stormwater & Green Infrastructure III
Moderator Barbara Doll Marc Beutel Eban Bean
8:00 am – 8:15 am (56) Joe Garner – Beginning a Career in Environmental Restoration and Planning: A Perspective for Students Looking to Join the Workforce (61) Sumaia Islam – Ammonia Oxygen Demand Determination for the Design of an Oxygenation System in a Water Supply Reservoir (66) Shaddy Alshraah – Soil Tillage for Stormwater Infiltration: Effects of Amendments and Vegetation Type Over Time
8:15 am – 8:30 am (57) Michael Pannell – Stream Mitigation Design and Construction for an Over Widened Bedrock Channel (62) Nathan Stoltzfus – Forming Public-Private Partnerships to Identify and Manage Agricultural Fields with Elevated Phosphorus in the Western Lake Erie Basin (67) Mohammad Nayeb Yazdi – Assessing the Effect of Retention Ponds in Potentially Reducing or Buffering Downstream Loads to the Bay
8:30 am – 8:45 am (58) Nolan Williams – A Methodology for Developing a Compound Flooding Model Using Long-Term Data Collection and Basic Stochastic Hydrology (63) Tiffany Messer – Assessing the Water Quality Cocktail Entering Recreational Lakes (68) Ani Jayakaran – The Role of Porous Asphalt in Stormwater Mitigation in Urban Landscapes
8:45 am – 9:00 am (59) Paul Le Bel – Effective Stream Restoration Construction Management within Piscataway Creek (64) Byran Fuhrmann – Mercury Cycling in a Eutrophic Reservoir (69) Alessandra Braswell – Stormwater Management for Coastal Communities: A Case Study Review
9:00 am – 9:15 am (60) Joel McSwain – Expanding Asset Protection to Include Stream Restoration Techniques (65) Melissa Conn – Seasonal Zooplankton Community Structure and Mercury Bioaccumulation in a Hypereutrophic Reservoir (70) Sarah Waickowski – Hydrologic and Water Quality Impacts of a Green Street Retrofit in Fayetteville, North Carolina

(56) Beginning a Career in Environmental Restoration and Planning: A Perspective for Students Looking to Join the Workforce

Presenter: Joe Garner, GreenVest, LLC, garnercjoe@gmail.com

Abstract: This presentation focuses on my experiences as an entry-level environmental scientist including the transition from an undergraduate student and highlights my role providing construction oversight and project support at GreenVest, LLC. The Mattawoman Creek Mitigation Site (MCMS) is an eighty (80+) acre mitigation bank site in Maryland that features integrated stream and wetland components. Old Womans Run (OWR), the focus of stream restoration, was previously impaired and disconnected from its floodplain by an artificial levee created when the stream was historically straightened. A lighter-touch design approach was taken to restore OWR, achieving floodplain reconnection through strategically placed levee breaches and constructed in-stream large woody debris structures. Adjacent floodplain wetland restoration was designed and constructed to retain water for the maximum extent practical during more frequent (1.25, 1.5 year) out-of-bank events, supporting infiltration and evapotranspiration. In the northern portion of the site, large woody debris structures were installed in an unnamed tributary, providing habitat and promoting hydrology into adjacent restored wetlands. Various arrangements of brush and wood debris were used to create stream and wetland habitat. Experiences as an entry level scientist conducting stream and wetland restoration oversight have revealed many skills and lessons (some of which are not typically taught collectively in a college curriculum[PP1] ) that would benefit aspiring ecological engineers and scientists. I hope to share insight on what students can expect when looking for environmental jobs and the skills they can focus on as undergraduates to better prepare themselves. This presentation is meant to describe my experiences with this innovative restoration project and foster discussion amongst students and those interested in ecological restoration.

Biography: Joe Garner is a recent graduate from the University of Maryland College Park with a B.S. in Environmental Science and Technology. He presented at last year’s Annual AEES Conference on his research that assessed the application of harvested algae from an algal turf scrubber as a fertilizer. He is now an entry level environmental scientist with GreenVest, LLC, and provides construction oversight on large scale ecological restoration projects. Outside of his work with GreenVest, he continues to conduct research into the applications of algal fertilizer with Dr. Patrick Kangas, professor at the University of Maryland, and former AEES President.


(57) Stream Mitigation Design and Construction for an Over Widened Bedrock Channel

Presenter: Micheal Pannell, S&ME, Inc., mpannell@smeinc.com

Co-Authors: Patrick McMahon, S&ME, Inc., pmcmahon@smeinc.com; Brent Wood, S&ME, Inc., bwood@smeinc.com; Ken Barry, S&ME, Inc., kbarry@smeinc.com

Abstract: Many stream mitigation projects use the natural channel design methodology.  But this approach is sometimes difficult to apply, particularly when performing on-site mitigation, where the constraints of the site often dictate what is possible.  This presentation provides a look at the challenges of designing and constructing an on-site stream mitigation project comprising the enhancement of 850 feet of perennial stream channel lying on bedrock with adjacent fringe wetlands.  Because the stream profile follows existing bedrock and the fringe wetlands were not to be disturbed, neither plan form realignment nor profile modification were proposed.  For this reason, a reference reach was not considered in the final design.

The project challenges included design and construction of an appropriately dimensioned channel on bedrock while minimizing impacts to the adjacent wetlands.  Baseline data for the existing stream were collected and used to establish a bankfull discharge for the proposed design.  The existing channel dimension values were compared with published regional curve data for Ecoregion 71i to calibrate bankfull for the observed cross sections.  Following calibration to the observed bankfull discharge, the slope was calculated based on the length of the existing alignment, and a new riffle cross section was developed.  This restoration design implements a novel approach for using coir blocks to form the new channel cross section on the bedrock surface.


(58) A Methodology for Developing a Compound Flooding Model Using Long-Term Data Collection and Basic Stochastic Hydrology

Presenter: Nolan Williams, Robinson Design Engineers, nw@robinsondesignengineers.com

Co-Authors: Joshua Robinson, MS, PE, Robinson Design Engineers, jr@robinsondesignengineers.com; Anand Jayakaran, PhD, PE, anand.jayakaran@icloud.com

Abstract: Coastal regions across the globe have become increasingly susceptible to flooding impacts associated with urbanization, hydromodification, changing weather patterns, and the increased frequency and intensity of tropical storm systems. However, when flooding occurs in coastal environments, it can rarely be attributed to one single driver. In many cases, flooding in this environment can be considered as “Compound Flooding;” that is flooding that results from the combined effects of several different hydrologic drivers, specifically rainfall-runoff processes and tidal forces. The complex flood behaviors of systems affected by both tidal effects and rainfall-runoff processes are often simulated using hydrology and hydraulic modeling software packages. The process of developing and operating computational models capable of accurately simulating these behaviors is resource intensive, and without proper calibration and verification, these models are capable of grossly misrepresenting system behaviors. As an alternative, this study details a method for predicting general flood behaviors using simple mathematical models developed using field data collection, long-term monitoring, and basic statistical hydrology analyses.

For this study, water level and rainfall depth recording instrumentation were installed along a tidally influenced tributary of the Ashley River, called Church Creek, located in Charleston, SC. Using data collected from this gage station, along with publicly available data from a series of gages operated by government agencies, regression analyses were used to mathematically isolate the effects of tide and rainfall-runoff on the peak water level of Church Creek. After isolating the separate effects of these two processes, a “Combined Flooding Function” was developed for predicting the peak water level in Church Creek based on the peak tide in the Ashley River and a multi-day rainfall total in the watershed. Using the function, joint-probability analyses were then used to investigate the recurrence of flooding based on a range of tide conditions and rainfall depths.

Biography: Nolan Williams is a Hydrologist and Engineer-in-Training with Robinson Design Engineers in Charleston, South Carolina. Nolan has a BS in Civil Engineering from the Georgia Institute of Technology. While at Georgia Tech, Nolan was involved in several projects and research efforts regarding urban hydrology and the use of green infrastructure in stormwater management. Since joining Robinson Design Engineers, Nolan has taken a special interest in furthering the use of data collection, long-term monitoring, and stochastic hydrology in engineering.


(59) Effective Stream Restoration Construction Management within Piscataway Creek

Presenter: Paul Le Bel, Hazen and Sawyer, plebel@hazenandsawyer.com

Abstract: The Washington Suburban Sanitary Commission (WSSC) retained Hazen to design protection measures for two dozen exposed sanitary sewer assets within the Piscataway Creek Basin in Prince George’s County, Maryland, as part of its sewer repair, replacement and rehabilitation program. Hazen stream restoration designers developed Priority I-IV designs to restore stable channel form and function based on asset location, site constraints and erosion severity. Construction began in December of 2015 and was completed in 2019. During construction, Hazen designers worked closely with WSSC and its contractors to ensure protection measures met design intent. This presentation highlights several construction management topics deemed important to the owner (WSSC), the contractors, and the designers, including: (1) the determination of construction oversight budget and schedule; (2) the importance of designer presence during the first installation of any structure type (e.g., cross vane, j-hook); (3) communication and reporting mechanisms to provide both immediate/actionable feedback and record documentation; (4) the utility of  scheduling tree removal site walks immediately after disturbance stakeout but prior to mobilization; (5) the development of efficient construction management habits; (6) satisfactory quality control of construction management reporting; and (7) the importance of flexibility to accommodate changes in existing conditions (such as new asset exposure, the complete loss of assets occurring between design and construction, unanticipated  bedrock, and new  stormwater pipe discharges). This presentation will touch on lessons learned throughout the construction phase of the project, as well as key analyses and design decisions which affected construction.

Biography: Paul Le Bel is a Principal Engineer with Hazen who specializes in analysis, design and construction oversight for stream restoration, asset protection and urban stormwater management projects. Paul works throughout the Mid-Atlantic region to provide stream assessment, design and construction phase services for time sensitive projects. Paul works extensively with owners and contractors during the construction phase to ensure design intent is met and appropriate guidance is provided for field adjustments. He works out of the Fairfax, VA office where he is frequently involved in projects that benefit the Chesapeake Bay.


(60) Expanding Asset Protection to Include Stream Restoration Techniques

Presenter: Joel McSwain, Hazen and Sawyer, jmcswain@hazenandsawyer.com

Abstract: Throughout the Southeast and Mid-Atlantic, urban streams have eroded and incised over the years from more intense flow regimes.  One by one, these streams expose sanitary assets buried decades ago.  The repair and protection of damaged and exposed sanitary assets is often seen as a more immediate need than stabilizing the impaired stream that is often the culprit for the damage.  The site evaluations commonly arrive at the question of spot repair and localized hard armoring versus addressing incision or lateral migration of an impaired and incised stream.  Separate departments and separate budgets for municipal sanitary and stormwater can make coordination difficult, and the fact that critical asset exposures often appear one at a time can make larger and more expensive stream restoration solutions difficult to justify; however, there are clear benefits in providing a more holistic solution.

This presentation will focus on reasons to consider protection of sanitary assets and the restoration of degraded streams together for the best results including long-term asset stability, protection of other infrastructure, water quality, and added ecological benefits.  Included will be evaluation tools and criteria for making design decisions, and discussion about what can be done by both public utilities and private consultants to ensure that the most efficient and effective approaches are considered and implemented.  It will be shown how different municipalities have used the need for asset protection as an opportunity to evaluate surrounding stream conditions and then make informed decisions about the most effective locations and approaches for asset protection and stream restoration.

Biography: Joel McSwain is a Principal Scientist with Hazen and Sawyer and specializes in stream and wetland restoration.  He has over 12 years of experience in the field and currently serves as lead stream restoration designer and project manager on a variety of stream and stormwater related projects.


(61) Ammonia Oxygen Demand Determination for the Design of an Oxygenation System in a Water Supply Reservoir

Presenter: Sumaia Islam, Georgia Southern University, si00614@georgiasouthern.edu; Francisco Cubas, Georgia Southern University

Co-Authors: Armond Jenkins, Georgia Southern University

Abstract: The Occoquan Reservoir, located in northern Virginia, is a eutrophic water supply reservoir that is part of an indirect potable reuse system. After the onset of thermal stratification, anaerobic conditions develop in the hypolimnion during summer months. To protect the reservoir’s water quality, an oxygenation system was installed and operated for eight years during summer months to avert the onset of anaerobic conditions in the hypolimnion and subsequent release of reduced substances from the sediments.  During the warmest months of the year, oxygen depletion rates above the sediment-water interface exceed artificial oxygen supply rates resulting in ammonia accumulation in the water column.  Field observations and laboratory experiments revealed that sediment ammonia release rates ranged from 170-542 mg/m2∙day.  At these rates, ammonia concentrations reached values as high as 5.6 mg-N/L in the absence of oxygen, and as high as 2 mg-N/L when the oxygenation system was operational.  Ammonia release rates were also used to determine the total ammonia oxygen demand during the stratification period.  Results revealed that the hypolimnetic ammonia oxygen demand might reach values as high as 77 metric tons of oxygen during a stratification period of 140 days.  Furthermore, ammonia oxygen demand represented 20-100%, and in some cases more than 100% of the hypolimnetic oxygen demand estimated from oxygen depletion curves, which are commonly used to design aeration/oxygenation systems. Ammonia oxygen demand is typically considered quite negligible when compared to the demand from organic matter or other reduced substances (e.g., iron and manganese). However, this study revealed that under extended anaerobic periods, ammonia oxygen demand was three times higher than the total oxygen deficit calculated from oxygen depletion curves measured in the reservoir. These results highlight the significance of estimating benthic fluxes of reduced substances (e.g. ammonia) while designing any oxygenation system.

Biography: Sumaia Islam is a grad student and Research Assistant at Civil Engineering Department at Georgia Southern University. Her research focused on release of reduced substances in aerobic and anaerobic condition for sediments. She is also working with characterization of organic matter released from sediment during hypolimnetic anoxia. Before starting her Masters’, she graduated in Urban and Regional Planning from Bangladesh University of Engineering and Technology. She also worked for almost 1.5 years on different projects focused on sustainable water resource management, climate change mitigation and adaptation, water security for the poor and so on.


(62) Forming Public-Private Partnerships to Identify and Manage Agricultural Fields with Elevated Phosphorus in the Western Lake Erie Basin

Presenter: Nathan Stoltzfus, Ohio State University, stoltzfus.12@osu.edu

Co-Authors: Dr. Jay Martin, Ohio State University Department of Food, Agricultural, and Biological Engineering, Martin.1130@osu.edu; Dr. Margaret Kalcic, Ohio State University Department of Food, Agricultural, and Biological Engineering, kalcic.4@osu.edu; Greg LaBarge, Ohio State University Extension, labarge.1@osu.edu; Dr. Robyn Wilson, Ohio State University School of Environment and Natural Resources, wilson.1376@osu.edu; Dr. Brian Roe, Ohio State University Agricultural, Environment, and Development Economics, roe.30@osu.edu; Dr. Ryan Winston, Ohio State University Department of Food, Agricultural, and Biological Engineering, winston.201@osu.edu; Dr. Jessica D’Ambrosio, The Nature Conservancy, jessica.dambrosio@tnc.org; Dr. Kevin King, USDA ARS, kevin.king@ars.usda.gov

Abstract: Agricultural production can lead to significant nutrient loss that diminishes surface water quality. Globally, this results in eutrophication and harmful algal blooms (HABs) as is the case for the western Lake Erie basin Within this basin, the Maumee watershed is the largest phosphorus (P) source contributing to recurrent HABs, and this basin is dominated by agricultural land use. Some agricultural fields have soil test P concentrations exceeding maximum recommended agronomic levels of 40 ppm with more than 5% of cropland having soil test P levels exceeding 2.5 times the that recommendation (100 ppm). These “elevated P fields” are at risk of contributing disproportionate P loads that can persist for decades. Targeting these elevated P fields with best management practices (BMPs) is likely to be effective at reducing nutrient loads and the severity of future harmful algal blooms. Field-level soil data is needed to find and target these sites; however, the proprietary nature of this data inhibits this approach. To overcome this barrier, we have formed a public-private partnership with nutrient service providers (NSPs) to demonstrate how proprietary data can be used to target BMP implementation and test hypotheses about elevated P fields. Partner NSPs provide de-identified data used to identify potential sites for BMP implementation. Additionally, this data will be used to improve knowledge of the extent and distribution of elevated P fields in the watershed. We will work with the NSPs to recruit the farmers to participate in a study that implements BMPs on their fields. Water quality monitoring combined with socioeconomic analyses and watershed modeling will predict the impact that BMPs can have by targeting these fields. An extension program will promote the application of BMPs on elevated P fields and highlight the ability of public-private partnerships to address water quality issues.

Biography: Nathan Stoltzfus is a Professional Engineer with experience in site design, stream restoration design, hydrologic and hydraulic modeling, construction oversight, and project management. This, combined with his agricultural experience growing up around and working on family farms is helping him in his current role as Project Manager/Project Engineer at Ohio State University working on a large agricultural water quality research project


(63) Assessing the Water Quality Cocktail Entering Recreational Lakes

Presenter: Tiffany Messer, University of Nebraska – Lincoln, tiffany.messer@unl.edu

Co-Authors: Mary G. Keilhauer, University of Nebraska – Lincoln, mkeilhauer2@unl.edu; Dan D. Snow, Nebraska Water Center, dsnow1@unl.edu; Aaron Mittelstet, University of Nebraska – Lincoln, amittelstet2@unl.edu

Abstract: Neonicotinoid insecticides are one of the most important common use pesticide (CUP) classes present in agricultural and urban landscapes and their downstream aquatic ecosystems. Further, neonicotinoids have become ubiquitous in midwestern streams, which has resulted in an emergence of these contaminants being found in finished Midwestern drinking water and becoming associated with honeybee colony collapse disorder. Currently, little is known regarding human exposure to these contaminant mixtures in recreational reservoirs and lakes. The objective of this study was to examine and compare the potential for recreational exposure in three Midwestern reservoirs with varying size and land use (i.e., intensive agriculture, urbanized watersheds). Six sampling campaigns were conducted at three lake sites between April through October in 2018. Polar organic chemical integrative samplers (POCIS) were placed at the inlets of each lake and monthly samples were analyzed for 7 neonicotinoids (acetamiprid, clothianidin, dinotefuran, imidacloprid, metalaxyl, thiacloprid, and thiamethoxam). The use of POCIS enabled estimation of time weighted average concentrations of CUPs. Further, monthly grab water quality samples were taken at the POCIS location, midpoint of each lake, and outlet of each lake. All CUP sample extracts were analyzed using liquid chromatography tandem mass spectrometry (LC-MS/MS) analysis. CUP loading rates were determined using water level dataloggers (Onset HOBO) and a SonTek River Surveyor to measure hourly water levels, seasonal flow velocities, and geometric channel dimensions. Temporal and pesticide loading differences were observed between watersheds feeding urban and rural reservoirs. Several measured pesticide concentrations exceeded acute and chronic ecological limits. Results were used to develop vulnerability maps for CUP contamination the three recreational waters and estimate the seasonal influx of CUPs into these recreational lakes with the intention to provide recommendations of in situ best management practices for managing concentrations in the future.

Biography: Dr. Messer is an assistant professor in the Biological Systems Engineering Department  and School of Natural Resources at the University of Nebraska-Lincoln. She holds degrees in Biosystems and Agricultural Engineering (University of Kentucky, B.S., 2008) and Biological and Agricultural Engineering (North Carolina State University, M.S. 2010, PhD, 2015). Messer completed a postdoctoral appointment in the Nicholas School of the Environment at Duke University (2015-2016). Her research interests reside at the intersection of engineering, ecology, and agriculture with an emphasis on environmental biogeochemistry and water resources in agricultural landscapes. Her research focuses on identifying, tracing, and treating contaminants in ecosystems impacted by human disturbances.


(64) Mercury Cycling in a Eutrophic Reservoir

Presenter: Byran Fuhrmann, UC Merced, bfuhrmann@ucmerced.edu

Co-Authors: Marc Beutel, Jeff Pasek, Sarah Brower, Andrew Funk

Abstract: Mercury is a toxic heavy metal with no known biotic function. Human exposure to elevated levels can cause a variety of serious health problems such as neurological disorders, kidney failure, paralysis, and even death. In the US, mercury contamination is prevalent in approximately 50% of EPA superfund sites (Bigham et al., 2016) and the World Health Organization (WHO) currently considers mercury to be one of the top ten chemicals of major public health concern (Bose-O’Reilly et al., 2010). Mercury is typically found only in trace concentrations in natural ecosystems, however, it can be transformed into an organic form (methylmercury or MeHg) which has a high potential for bioaccumulation in aquatic food webs and is therefore a priority contaminant for lake and reservoir managers. The production of MeHg has been associated with the depletion of oxygen in eutrophic reservoirs during thermal stratification. The study tracked monthly changes in sediment and water column biogeochemical parameters during thermal stratification in Hodges Reservoir, a eutrophic reservoir in southern California, in order to assess which factors could be correlated with MeHg production. Attention was given to substrate availability for both MeHg production and anaerobic metabolism. Chemical speciation of mercury in sediment was determined monthly and changes with time were documented. A temporal mass balance of MeHg in the sediment, water column, and particulate matter was created in order to examine production and transport of MeHg. Thermal stratification in Hodges reservoir generally begins in early April and anaerobic conditions prevail within a few weeks, lasting until November. This extended period of anaerobic conditions makes it an ideal study site for temporal biogeochemical patterns, which fluctuated extensively throughout this period.

Biography: Byran Fuhrmann is currently a 3rd year PhD student in Environmental Systems at the University of California, Merced (UC Merced), where he studies mercury cycling in lakes and reservoirs. During his first year at UC Merced, he won the school wide graduate student presentation competition entitled “GradSlam!” and was selected to represent UC Merced in the state wide competition. He became interested in water quality after receiving his BS in Chemistry from Humboldt State University and joining an environmental laboratory as the quality assurance manager. During this time, he also completed an MBA focused on strategic sustainability from Humboldt State University. Afterwards, he went on to receive an MS in Environmental Engineering Sciences from the University of Florida before enrolling in the PhD program at UC Merced. He can be contacted at 714-329-6840 or at hgwaterchem@gmail.com.


(65) Seasonal Zooplankton Community Structure and Mercury Bioaccumulation in a Hypereutrophic Reservoir

Presenter: Melissa Conn, University of California, Merced, mconn4@ucmerced.edu

Co-Authors: Marc Beutel, Ph.D, University of California, Merced, mbeutel@ucmerced.edu; Byran Furhmann, University of California, Merced, bfuhrmann@ucmerced.edu; Sarah Brower, Ph.D, City of San Diego, SBrower@sandiego.gov

Abstract: Mercury and how it cycles in aquatic systems are current and future interests as regulations become increasingly demanding in efforts to reduce methylmercury (MeHg) in fish from reservoirs. California has numerous reservoirs that have been operating for decades as well as accumulating atmospheric mercury, which can eventually become MeHg. As mercury standards tighten to better protect human and wildlife health, there is growing interest in examining how MeHg is transported ecologically to inform potential option for mitigating MeHg production. Hypolimnetic oxygenation is an in-situ management tool that may prevent MeHg production by means of a well-oxygenated sediment-water interface, thereby inhibiting sulfate-reducing bacteria that produce MeHg.

The reservoir of interest, Hodges Reservoir, San Diego, will be installing an oxygenation system which will begin operation during the summer of 2020. Zooplankton community structure and mercury levels will be analyzed before and after oxygenation in an effort to determine how seasonal blooms impact zooplankton density and structure as well as potential bioaccumulation trends. This presentation will introduce the Hodges Reservoir oxygenation project and present data on seasonal patterns of zooplankton community structure and mercury content for 2017 and 2018. Results suggest that there is a “hot spot” for MeHg uptake into the base of the food web in the spring when thermal stratification is weak (allows MeHg to advect upwards into surface waters) and phytoplankton and zooplankton density is relatively low (MeHg is bio-concentrated into small biomass compartment).

Biography: Originally from Reno, Nevada, I received my BS in Environmental Science. Both my studies and fieldwork have emphasized aquatic ecology, limnology and stream/fish habitat monitoring. I moved to San Francisco for a few years and worked for an environmental consulting firm and decided to apply to a masters program in Environmental Systems at University of California, Merced. Having always had an interest in environmental chemistry, this became my chance to pivot back to my interest in limnology and to study trophic mercury bio-accumulation. Professionally, I plan to continue working in the water quality realm. I enjoy just about any outdoor activity but especially surfing and rock climbing.


(66) Soil Tillage for Stormwater Infiltration: Effects of Amendments and Vegetation Type Over Time

Presenter: Shaddy Alshraah, North Carolina State University, shalshra@ncsu.edu

Abstract: Managing stormwater to reduce volumes, peak flows, and pollutant loads is important for the North Carolina Department of Transportation (NCDOT) in order to comply with state and federal permits. Vegetation is an important element of roadside stormwater control measures (SCMs), as healthy roadside vegetation can reduce erosion and runoff.  While grass is the typical vegetation along highways, wildflowers have also been planted by the NCDOT for over 30 years on roadside areas primarily for beautification. There may be additional areas that could be planted to wildflowers instead of grass to reduce maintenance and improve pollinator habitat. Previous studies have established that tillage and followed by establishment of a vigorous stand of vegetation can greatly increase infiltration relative to compacted soils.  The main goal of this study is to evaluate the potential improvements in infiltration through the use of tillage together with compost and either grass or wildflowers over three years.  At three NCSU experiment stations representing the Coastal Plain, Piedmont, and the Mountain regions, either wildflowers or grass were planted on tilled soil with or without compost. Infiltration, bulk density, root biomass, and soil cone index were measured every six months over a 24 month period. The results for infiltration after 24 months suggested few differences among treatments at all locations, but relatively high infiltration rates (18 to 22 cm.h-1) on average. Lower bulk density values were maintained in the compost-amended plots. Grass had relatively higher root mass than wildflowers within 30 cm depth. Cone index values increased with depth but were below 300 psi in the top 15 cm (tillage depth). Tractor traffic during mowing substantially reduced infiltration rates in the wheel tracks but there was some evidence of recovery in the compost-amended wildflower plots. The results suggest that wildflowers can provide effective infiltration in vegetated SCMs and that compost amendment may also help to limit the effects of traffic required for vegetated SCM maintenance.

Biography: Shaddy is a 3rd year Ph.D. student at NC State University majoring Soil Science. He received his Bachelor degree in Soil, Water, and Environment and a  Master degree in Integrated Natural Resources Management from Jordan University of Science and Technology, Jordan.  Also, he obtained a second master’s degree from  Tuskegee University, Alabama. His current research focuses on the potential improvements in stormwater infiltration through the use of tillage and amendments under different vegetation types.


(67) Assessing the Effect of Retention Ponds in Potentially Reducing or Buffering Downstream Loads to the Bay

Presenter: Mohammad Nayeb Yazdi, Virginia Tech, mnyazdi@vt.edu

Co-Authors: David Sample, Virginia Tech, dsample@vt.edu; Durelle Scott, Virginia Tech, dscott@vt.edu

Abstract: Urbanization has altered watershed hydrology by increasing impervious surfaces, and changing drainage patterns that increase volume and velocity of runoff. These changes increase sediment and nutrient loads to downstream waters result in poor surface water quality threatening aquatic ecosystem health. In response, retention ponds have become one of the alternative management practice to capture large volumes of runoff and trap suspended sediments and associated pollutants. The goal of this study is to better understand the behavior of a retention pond for removing nitrogen (N), phosphorous (P), and sediment, located in the City of Virginia Beach, which is within the Coastal Plain region and is part of the Chesapeake Bay watershed; which has a focus on reducing sediment and nutrients to reduce eutrophication of the Bay. To achieve this goal, we monitored water quality at the inlets and outlet of the retention Storm-weighted composite water samples were collected and analyzed for total N (TN), total P (TP), total suspended solid (TSS), ortho-phosphorous (PO4), total Kjeldahl nitrogen (TKN), nitrates (NOx), nitrite (NO2), ammonia (NH4), and particle size distribution (PSD). We estimated the efficiency of a coastal retention pond for removal N, P, and sediment; and investigated the effect of storm size, antecedent conditions, and residence time on the performance of the pond. During storm events in cold weather, we found the pond reduced the level of TSS and P significantly, while it exported N and the level of N increased in outflow of the pond. Also, PSD indicated that particle size in outflow of the pond decreased considerably in comparison to inflows. Understanding the functioning and performance of retention ponds within Coastal Virginia will help improve sediment and nutrient removal, and thus help improve the health of downstream ecosystems.

Biography: Mohammad Nayeb Yazdi is a Ph.D. candidate, studying biological system engineering at Virginia Tech. His research interests are watershed management by developing watershed models such as SWMM and HSPF for various scales of watersheds, evaluating the impacts of non-stationary events such as change of land-use and climate on hydrology and water quality of watersheds, and monitoring program for investigating of urban and agricultural runoff. At the present, Mohammad is working on two monitoring programs related to a retention pond and various land uses in Virginia Beach.


(68) The Role of Porous Asphalt in Stormwater Mitigation in Urban Landscapes

Presenter: Ani Jayakaran, Washington State University, anand.jayakaran@wsu.edu

Co-Authors: Thorsten Knappenberger, Auburn University, knappi@auburn.edu; John D Stark, Washington State University, starkj@wsu.edu

Abstract: Permeable pavements are one of several GSI techniques that are increasingly being used across the country to mitigate the effects of stormwater on downstream receiving waters. The performance of a 9-cell replicated asphalt pavement test facility was quantified in terms of water quantity and quality treatment, over a period of five years. The asphalt test facility has 9 lined cells – 3 cells are constructed with conventional asphalt and 6 with porous asphalt. Runoff from the impervious cells acted as a control and were compared to runoff from the pervious cells. Artificial and natural storm events were used to test both hydrologic and biogeochemical remediation of the two systems. Pollutants evaluated were suspended sediments, metals, nutrients, and hydrocarbons. Results from this work show that porous asphalt pavements are able to infiltrate as much as 99.5% of incident rainfall. Results also showed that porous asphalt pavements are highly efficient at removing total suspended solids (93.4%) especially coarse material, total lead (98.4%), and total zinc (97.8%). Dissolved metals and polycyclic aromatic hydrocarbons were not removed to any appreciable level. Removal efficiencies for total lead, total zinc, motor oil, and diesel hydrocarbons improved with the age of the system. Annual maintenance of the pavements did not yield significant pollutant removal efficiency differences between maintained and unmaintained PA cells. Research objectives associated with a follow up study to examine the incorporation of carbon fiber to strengthen porous asphalt pavements will also be presented.

Biography: Ani Jayakaran is an Associate Professor with Washington State University Extension. His role is to meet extension and research needs in a region experiencing the impacts of high urbanization, drought, and a changing climate. The scope of his work extends to the entire state of Washington, and involves disseminating strategies to manage water resources using Low Impact Development, and improving current engineering designs with ecosystems-centric solutions for handling stormwater through applied research. Ani holds a Bachelor’s degree in Civil Engineering from India, and graduate degrees in Civil Engineering (MS) and Agricultural & Biological Engineering (PhD) from Ohio State University. He is a licensed  engineer in the states of Washington and South Carolina.


(69) Stormwater Management for Coastal Communities: A Case Study Review

Presenter: Alessandra Braswell, Geosyntec, abraswell@geosyntec.com

Abstract: Designing stormwater management systems for coastal communities can be challenging due to many environmental factors. High groundwater, tidal effects, and flat topography present a reduced opportunity for gravity-driven systems; conventional “pipe and pond” methods are thus often not applicable. Additionally, sea level rise and a changing climate add an inherent level of complexity in designing drainage and stormwater management solutions for coastal communities compared to other regions. This presentation will cover a selection of stormwater management projects implemented in coastal communities. These case studies showcase some of the basic stormwater design principles for coastal communities, including methods like infiltration at the source, groundwater lowering, and retrofit improvements that consider tidal influences. Lessons learned and opportunities for improvement will be highlighted.

Biography: Dr. Alessandra Braswell offers 7 years of water resources engineering experience with a focus in urban stormwater management, stormwater control measure (SCM) selection and design, and stormwater master planning. She received a Ph.D. and M.Eng. from North Carolina State University in Biological and Agricultural Engineering and a B.Sc. from University of Florida in Agricultural and Biological Engineering. Her graduate research focused on stormwater management in the urban environment, including modeling the annual hydrology of permeable pavements and assessing the water quality benefits of low impact development (LID) treatment trains. Alessandra has instructed stormwater design workshops throughout North Carolina and Ohio on topics including green streets, permeable pavement, and modeling SCM function under future climate scenarios.


(70) Hydrologic and Water Quality Impacts of a Green Street Retrofit in Fayetteville, North Carolina

Presenter: Sarah Waickowski, North Carolina State University, sewaicko@ncsu.edu

Co-Authors: Katy Shaneyfelt, Muller Engineering Company, kshaneyfelt@mullereng.com; Dr. William Hunt, North Carolina State University, wfhunt@ncsu.edu

Abstract: Impervious cover associated with urbanization has direct hydrological and water quality effects on landscapes and surface waters. Green streets have the ability to mitigate the impact of urban development by reducing and treating stormwater runoff at its source. An urban two-block corridor has been retrofitted in Fayetteville, North Carolina with green infrastructure to manage stormwater runoff. This is the first comprehensive green street in North Carolina, and the retrofit involves redeveloping an entire corridor during scheduled street repair. Stormwater control measures (SCMs) include: bio-infiltration bump-outs, permeable pavement, and suspended pavement systems. This study aims to evaluate the ability of the green street to manage stormwater runoff in an urban area and to gain a large-scale perspective on the environmental impacts of green streets. Water quality samples and stormwater runoff data have been analyzed at both the street level and individual suspended pavement systems to determine any significant statistical differences between the pre- and post-retrofit hydrology and water quality data. These data will be incorporated into pre- and post-retrofit PCSWMM models to optimize green street design in North Carolina. Monitoring green streets both pre- and post-retrofit is crucial in understanding and recognizing green streets’ environmental impacts.

Biography: Sarah Waickowski is an Extension Engineer under the direction of Dr. Bill Hunt. Her responsibilities include applied research, demonstration projects, and outreach focusing stormwater control measures. She has experience designing and installing stormwater wetlands, wet pond retrofits, bioretention cells, street tree systems, and infiltration practices. She also assisted NC DEQ with the creation of the NC SCM Crediting Document.