Application of a Monitoring Plan for Storm-Water Control Measures in the Philadelphia Region

Case StudyApplication of a Monitoring Plan for Storm-WaterControl Measures in the Philadelphia RegionAndrea L. Welker, P.E., M.ASCE1; Lynn Mandarano, P.E.2; Kathryn Greising3; and Krista Mastrocola4Abstract:Storm-water control measures (SCMs), also known as storm-water best management practices (BMPs), are increasingly beingused to mitigate the impacts of development and restore the hydrologic cycle. This paper presents a three-tiered monitoring plan that can beused to determine the effectiveness of structural, nonproprietary SCMs in the Northeast United States. The monitoring plan offers three levelsof monitoring: high, medium, and low. This 1-2-3 approach is common in environmental monitoring. The monitoring protocol integrateshydrologic, water quality, and ecological factors and recommendations for equipment with the level of monitoring. The monitoring plan isthen applied to a rain garden on Villanova University’s campus in Villanova, Pennsylvania, and a cost analysis of the different monitoringlevels is provided.DOI:10.1061/(ASCE)EE.1943-7870.0000714.© 2013 American Society of Civil Engineers.CE Database subject headings:Stormwater management; Sustainable development; Best management practice; Pennsylvania;Monitoring.Author keywords:Storm-water control measures; Best management practices; Storm water; Monitoring; Low-impact development.Introduction and BackgroundAwareness of the deleterious effects of a disrupted hydrologic cyclehas increased dramatically over the past decade. Developmentdecreases pervious surfaces and plant cover, thus increasing theamount of runoff while decreasing infiltration and evapotranspira-tion. The runoff from developed areas entering nearby streamsmoves more quickly, is hotter, and carries more pollutants thanrunoff from undeveloped areas. The damage from this runoffnot only affects the area of development but also extends to theremainder of the watershed [e.g.,National Research Council(NRC) 2008;Wang et al. 2001;Schueler 1994;Traver andChadderton 1983]. Storm-water control measures (SCMs), alsoknown as storm-water best management practices (BMPs), areincreasingly being used to restore the hydrologic cycle and, as such,are a key component of low-impact development (LIDs) plans.Storm-water control measures are designed to serve three mainpurposes: (1) control the volume of runoff, (2) control the peakflow rates, and (3) reduce pollutants while restoring the naturalhydrologic cycle [Pennsylvania Dept. of Environmental Protection(PADEP) 2007].This paper presents a three-tiered monitoring plan that can beused to determine the effectiveness of structural, nonproprietarySCMs in the Northeast United States, depending on practicalityand budgetary issues. Monitoring is broken into three levels: high,medium, and low. Depending on the desired level of monitoring,recommendations are provided on the equipment and frequency ofmonitoring. The proposed plan combines traditional monitoring ac-tivities to assess storm-water volume and quality, with ecologicalcriteria recognizing the increasing trend to implement SCMs thathave been designed to mimic natural systems.The cost-effective inspection and monitoring of SCMs hasgarnered attention recently as township engineers are facedwith increasingly stringent regulations. The monitoring plan pre-sented in this paper seeks to fill a void by creating a succinct,multilevel approach to monitoring that can be applied to differenttypes of SCMs by using data obtained during rain events. Therecommended protocol incorporates the results and monitoringprotocols used in long-term monitoring studies (e.g.,Wadzuket al. 2010;Emerson et al. 2010;Kwiatkowski et al. 2007)and other assessment protocols (e.g.,Greising 2011;Aslesonet al. 2009;Hankins et al. 2008;Gulliver et al. 2010;Lindseyet al. 1992).This three-tiered monitoring plan is then applied to a rain gardenon Villanova University’s campus in Villanova, Pennsylvania,which is located approximately 24 km west of Philadelphia. Therain garden is part of the SCM demonstration park that has beenconstructed on campus over the past decade.Types of Storm-Water Control MeasuresEach SCM can be evaluated by considering five storm-water man-agement goals: (1) control the volume of runoff, (2) control peakrunoff rates, (3) reduce pollutants, (4) promote evapotranspiration,and (5) establish wetland structure and function. Goals 1–4 are tra-ditional runoff control goals whereas Goal 5 is a relatively recentgoal associated with the increasing use of SCMs designed to mimicnatural systems such as wetlands. Although many SCMs integratemore than one goal into their design, they are grouped according totheir primary goal in Table1.1Associate Professor, CEE Dept., Villanova Univ., 800 Lancaster Ave.,Villanova, PA 19085 (corresponding author). E-mail: andrea.welker@villanova.edu2Associate Professor, Dept. of Community and Regional Planning,Temple Univ., 580 Meetinghouse Rd., 209 West Hall, Ambler, PA 19002.3Engineer, Hach Mott McDo