American Water Resources Association

Student Poster Presentations

11 May 2016

Zachary Zukowski, Villanova University

Abstract: Rain gardens are one type of stormwater control measures (SCMs) which are used to reduce the quantity and improve the quality of water through infiltration and evapotranspiration (ET). Rain garden soils maybe either native or engineered media. Hydraulic conductivity is typically used as a performance measure of rain gardens, and this is most commonly determined in the field using infiltration testing. The most common type of infiltration testing is the double-ring infiltrometer (ASTM D3385); however, these systems require a large amount of water, can be difficult to install, and are time consuming to perform. Smaller single-ring infiltrometer tests can be easier to install and require less water. Additionally, more tests could be performed in the same amount of time, which means more area of a site can be tested. Since the accuracy of these methods is not well-documented, this study compared single ring infiltrometer data to historical recession rate data recorded in the pond of the SCM to determine the accuracy of this testing technique.

9 March 2016

Kellen Pastore, Villanova University

Abstract: In this poster, the design and implementation of low-cost instrumentation for green stormwater infrastructure (GSI) monitoring is discussed. As the use of GSI increases, monitoring becomes more and more critical to prove efficacy of the sites, inform future designs, and guide maintenance. This can be expensive and difficult, especially in the case of existing sites that need to be retrofitted. As part of Philadelphia's Green City, Clean Waters initiative, GSI sites are being installed throughout the city of Philadelphia. The Villanova Urban Stormwater Partnership (VUSP), the Villanova Center for Nonlinear Dynamics and Control (CENDAC), and Philadelphia Water (PWD) have partnered to study the effectiveness of these sites through extensive monitoring of select GSI installations. To accomplish this task, low-cost computing hardware is being leveraged to develop highly reliable, yet inexpensive instrumentation (data logging, sensor interfaces, telemetry, etc.) In the following, work being done in parallel at VU and PWD is presented with a focus on soil moisture monitoring.

Erica Forginone, Villanova University

Abstract: Road de-icing salt is one contaminant of concern in stormwater runoff, as it has been shown to have negative effects on plant and animal species, decrease biodiversity, and degrade environmental quality. It has been assumed that road de-icing salt would wash through watersheds with spring rains, as road salt (usually NaCl) is soluble, and chloride (Cl-) has long been considered a conservative tracer. However, many recent studies suggest that significant proportions of chloride mass may be retained within a watershed and that chloride levels resulting from winter salting activities may remain elevated late into summer months. Stormwater control measures (SCMs) have been praised for both volume reduction and improved water quality, but recent studies are showing that certain SCMs may increase the negative effects of road salting on the surrounding environment, such as contamination of groundwater, trace metal leaching, stratification in ponds, toxic effects, and reduced biodiversity. Because chloride poses a possible threat to downstream waters, a study was performed to study the fate and transport of chloride through one SCM, a constructed stormwater wetland (CSW), on Villanova‚Äôs campus.

The study had three main goals: i.) to determine if effluent concentrations of chloride from the CSW meet recommended EPA standards for both chronic and acute criteria; ii.) to compare total dissolved solids (TDS), conductivity, and chloride concentration data in order to further validate the data sets and also quantify correlations between each parameter; and iii.) to perform a mass balance of chloride to study the fate and transport of chloride upstream, within, and downstream of the CSW. Chloride concentrations and TDS/conductivity/chloride correlations were analyzed over a period of four years, from December 2011 - November 2015 and a mass balance was conducted with flow data for 2013 and 2014. 

13 January 2016

Scott Jeffers, Dexel University

Abstract: Human alterations to the environment provide infrastructure for housing and transportation but have drastically changed local hydrology. As a result of building with impervious surfaces such as concrete and asphalt, excess stormwater runoff is generated that causes land erosion, overburdens sewer infrastructure, and can pollute

receiving bodies of water with land contaminants. These issues can be mitigated using green stormwater infrastructure that seeks to mimic pre-developed hydrologic runoff conditions by capturing or slowing the flow of stormwater. When designing a stormwater management plan, it is important to know how well the green infrastructure will perform. One way to quantify this performance is by its hydrologic abstraction, or the water

volume the system will retain through processes such as infiltration, evapotranspiration,and storage capacity. The hydrologic abstraction can be determined using empirical methods by measuring inflow and outflow through the facility. In this study, hydrologic abstractions are determined for three different green infrastructure pilot facilities in New York City using empirical methods in order to determine the stormwater capture potential of each facility. While hydrologic abstractions vary with each storm as a result of varying antecedent conditions, it is recommended that the abstractions be presented as a range in order to accommodate for inherent intra-storm variability.

14 October 2015

Pablo Garza, Villanova University

Abstract: The William Penn Foundation awarded a grant to the Villanova Urban Stormwater Partnership (VUSP) for the monitoring of green stormwater infrastructure to be installed in the headwaters of creeks looked after by the Upstream Suburban Philadelphia Cluster team. One of the current three projects which will be monitored by the VUSP will be installed at the College Settlement Camp which is part of the headwaters of the Pennypack creek. The stormwater control measures (SCMs) consist of stream embankment restoration, a stormwater wetland and a rain garden. Construction of this effort began on October the 12th and the monitoring equipment will be installed shortly after completion.

9 September 2015

Stephanie Molina, Villanova University

Abstract: Stormwater management is a practice currently implemented in the form of rain gardens, green roofs and constructed stormwater wetlands to reduce the amount of nutrients and metals found in stormwater runoff. At Villanova University a Constructed Stormwater Wetland (CSW) has been implemented as a mean to reduce the nutrients and metals concentration in stormwater runoff that is entering the headwaters of Mill Creek. Over the years this stormwater control measure (SCM) has been analyzed as a whole but little is known on the mechanics of each individual section. The main objective of this research is to understand the basic mechanics of the Inlet Sedimentation Forebay with emphasis on Nitrogen and the Nitrogen Cycle.

Catherine Barr, Villanova University

Abstract: Recent studies on green roof water quality have indicated that extensive green roofs are a source for phosphates, and occasionally a source for nitrites as compared to conventional roofing systems.  In this study a green roof was compared to other vegetated land uses for nutrient retention because, unlike traditional roofs, green roofs have soil media and vegetation.  Green roof overflow was evaluated for water quality parameters including nitrogen and phosphorus species, chlorides, total suspended solids, and total dissolved solids.  Results indicated that the green roof generally retained nitrogen and released phosphorus; its performance was similar to or better than that of a grassy area and a wooded area in terms of nutrient retention, and performed similarly to an area that was at least 50% impervious.  Comparisons to USEPA recommended nutrient criteria for surface waters indicated that the green roof generally did not release nitrogen in excessive concentrations, however phosphorus export concentrations were above recommended levels.  In addition, green roof overflow was compared to that of a nearby stormwater wetland and a rain garden using data obtained from simultaneous storm testing events.  Both rain garden and stormwater wetland outperformed the green roof in terms of nutrient retention.  It is suggested that if nutrient export is a concern and space is available, green roof overflow could be diverted to other stormwater control measures which are designed to remove excess nutrients from stormwater runoff.

Taylor DelVecchio, Villanova University

Abstract:  Rain gardens are an effective means to control stormwater. The current state of practice only allows designers to calculate storage based upon the volume of the bowl and possibly the void space of the soil in Pennsylvania. Infiltration and evapotranspiration (ET) remain unaccounted for in design. Other design components, such as depth and soil type, are often restrictive and vague. In addition, current research demonstrates the importance of ET in vegetated stormwater control measures (SCMs), however, the soil mix guidelines heavily favor infiltration. Establishing soil mix guidelines that consider both infiltration and ET will enable greater creativity in SCM design and flexibility in siting SCMs. A total of twelve column non-weighing lysimeters will be used to evaluate soil mixes that span the USDA classification triangle (Figure 1). Six of the lysimeters will have a 46 cm depth and the other six with have a 20 cm depth. Both depth setups will contain the following soils: sandy loam (typical rain garden mix), loamy sand, loam, silt loam and clay loam. Five of the lysimeters will have switch grass. A bare control lysimeter will contain a sandy loam soil. Soil analyses (i.e. grain size analysis, organic content, liquid and plastic limits, soil-water characteristic curves, cation exchange capacity) will be performed on each soil.

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