APPLYING LOW IMPACT DEVELOPMENT PRACTICES TO MEET MULTIPLE OBJECTIVES: CASE STUDIES Scott D. Struck, Ph.D. 1 ; Steve Carter, P.E., Jamie Brescol, P.E., Dan Christian, P.E., D.WRE, Carol L. Hufnagel, P.E. Introduction As municipalities and counties seek solutions to various environmental challenges, sustainable solutions have become an integral part of the approach. Sustainable solutions provide multiple benefits that extend beyond the stated objective of the project. In evaluating sustainable solutions, it is important to be able to predict their performance relative to the primary project objective. Low Impact Development (LID) and Green Infrastructure Solutions (or upland runoff control techniques) are currently being encouraged by the U.S.EPA (EPA) as a management practice to contain and control stormwater at the lot or upland residential parcel level. These controls can be combined with larger regional controls to benefit water quality of watersheds through improved local stormwater quality and reduction combined sewer overflows (CSOs). This paper identifies several project applications where LID solutions are being evaluated or applied to accomplish an objective beyond localized stormwater management and to provide multiple benefits. In each case, the necessary scale of implementation and quantifiable benefit associated with the proposed work needed to be determined. Objectives The objective of each of the projects highlighted is to integrate LID and green infrastructure solutions along with other regional management opportunities to control flow quantity or quality and supplement current infrastructure. The analysis centers on how integration of smaller scale (LID and green infrastructure) and larger scale management can achieve overall watershed water quality and quantity benefits. The goal is also to provide additional information for managing urban watersheds and CSOs through application of green infrastructure solutions to meet multiple objectives and potentially inform regional or national approaches. CSO Retrofit in Toledo, Ohio Toledo, Ohio was required under the terms of a consent decree to develop a Long Term CSO Control Plan, which was submitted in 2005 and conditionally approved by U.S. EPA in April 2009. Approximately 40% of the City’s combined system is tributary to storage tunnels which were constructed in the early 1990’s. The approved plan requires the City to increase the level of control beyond what the tunnels can currently provide, reducing the frequency of discharge to between 3 and 4 times per year from the current 6 to 12 times per year. The City of Toledo is implementing a pilot project along Maywood Avenue that will better define the effect of green infrastructure on downstream runoff volumes. A goal of this project is to quantify the reduction in CSO volume (and consequently number of overflows per year) and associate a cost per gallon or overflow event reduction to use in future CSO planning efforts. The cost of green infrastructure will then be compared to proposed hard infrastructure to determine their overall efficacy. Currently, a $21.6 million, 1.6 million gallon tunnel expansion is proposed in the Long-Term CSO Control Plan and is equivalent to an additional 0.04-inch of catchment area WEFTEC 2010 Copyright ©2010 Water Environment Federation. All Rights Reserved. 7824