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JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION
<br />Vol5, No. AMERICAN WATER RESOURCES ASSOCIATION
<br />STORMWATER RUNOFF QUALITY AND QUANTITY FROM
<br />TRADITIONAL AND LOW IMPACT DEVELOPMENT WATERSHEDS'
<br />Erik S. Bedan and John C. Clausen
<br />August 2009
<br />ABSTRACT: The quality and quantity of residential stormwater runoff from a control, traditional, and low
<br />impact development (LID) watershed were compared in a paired watershed study. A traditional neighborhood
<br />was built using typical subdivision standards while a LID design was constructed with best management prac-
<br />tices including grass swales, cluster housing, shared driveways, rain gardens, and a narrower pervious concrete -
<br />paver road. Weekly, flow - weighted, composite samples of stormwater were analyzed for nitrate + nitrite - nitrogen
<br />(NO + NO -N), ammonia - nitrogen (NH -N), total Kjeldahl nitrogen (TKN), total phosphorus (TP), and total sus-
<br />pended solids (TSS). Monthly composite samples were analyzed for total copper (Cu), lead (Pb), and zinc (Zn).
<br />Mean weekly storm flow increased (600x) from the traditional watershed in the postconstruction period.
<br />Increased exports of TKN, NO + NO -N, NH -N, TP, Cu, Zn, and TSS in runoff were associated with the
<br />increased storm flow. Postconstruction storm flow in the LID watershed was reduced by 42% while peak
<br />discharge did not change from preconstruction conditions. Exports were reduced from the LID watershed for
<br />NH -N, TKN, Pb, and Zn, while TSS and TP exports increased.
<br />(KEY TERMS: best management practices; low impact development; nonpoint source pollution; runoff;
<br />stormwater management; urbanization; water quality; Connecticut.)
<br />Bedan, Erik S. and John C. Clausen, 2009. Stormwater Runoff Quality and Quantity From Traditional and
<br />Low Impact Development Watersheds. Journal of the American Water Resources Association (JAWRA) 45(4):998-
<br />1008. DOI: 10 .1111/j.1752- 1688.2009.00342.x
<br />INTRODUCTION
<br />Nonpoint sources are responsible for a large por-
<br />tion of the remaining water quality impairments in
<br />our nation's waters (USEPA, 2002). Urban storm -
<br />water runoff is one source of nonpoint pollution, and
<br />is responsible for contributing excess nutrients, bacte-
<br />ria, and toxic metals to receiving waters (USEPA,
<br />2002). Additionally, runoff from urban construction
<br />and development is reported as a source of pollution
<br />for 14 of the 18 National Estuaries (USEPA, 1994a).
<br />Traditional stormwater controls used in urban areas
<br />were designed to collect, convey, and discharge water
<br />quickly and efficiently (USEPA, 2000). Recently, the
<br />concept of low impact development (LID) has been
<br />introduced to mitigate the problems associated with
<br />urban stormwater runoff (Prince George's County,
<br />1999). LID is a design strategy to retain the storage,
<br />infiltration, runoff, and ground -water recharge that
<br />'Paper No. JAWRA -07- 0159 -P of the Journal of the American Water Resources Association (JAWRA). Received November 19, 2007; accepted
<br />March 17, 2009. © 2009 American Water Resources Association. Discussions are open until six months from print publication.
<br />2 Respectively, Natural Resource Specialist, North Central Conservation District, 24 Hyde Avenue, Vernon, Connecticut 06066; and Profes-
<br />sor, Department of Natural Resources Management and Engineering, University of Connecticut, 1376 Storrs Road, Storrs, Connecticut 06269
<br />(E- Mail/Clausen: john.clausen@uconn.edu).
<br />JAWRA 998 JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION
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