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Tuesday, May 19 10:30 - I I :45 AM Track 4 _ Multi-Objective Management- Moderator: Clancy Philipsborn FLOODPLAIN MANAGEMENT ISSUES ASSOCIATED WITH WIDENING OF THE TRl-STATE TOLLWAY John T, McCarthy, P.E. The Ulinois State Toll Highway Authority (ISlHA) is proceeding with plans to add a fourth lane to approximately 35 miles of the Tri-State Tollway and to remove the Deetfield Toll Plaza, The West Fork of the North Branch of the Chicago R~ver runs parallel to the roadway for approximately 2 miles, crossing underneath at one point The river has had a history of flooding and has been the subject of substantial work by the U.S, Army Corps of Engineers (Corps), including construction of a flood storage reservoir adjaceat to the tollway, ISlHA has agreed to comply with the Lake County Storm Water Conunission's (SMC) Watershed Development Ordinance, which covers storm water detention, wetland protection, storm water quality, and floodplain issues, Roadway widening will increase the rate of runoff from the right- of-way, so four detention basins have been designed to reduce the peak rate of runoff from the roadway. Wetlands were initially identified in two locations within the project. A wetland plant species listed as endangered was also identified within the roadside ditches along a part of the project, SO the Ulinois Department of Natural Resources concluded that the roadside ditches along the project were wetlands and that ISTHA must protect the endangered species by mitigating any damage to the wetland ditches, The quality of storm water discharge from the roadway is being addressed during the design, because of SMC requirements and because of concerns expressed by residents of a nearby lake that receives direct roadway runoff. Widening of the roadway would have resulted in a significant loss of floodplain storage volume that exists in the roadside ditches within the floodplain of the West Fork of the North Branch of the Chicago River. The SMC requires that floodplain storage losses be compensated for at a rate of 1.2 to 1.0. This is being handled by the design of the ditches within the right of way, DEVELOPING A MODEL FOR MULTI-OBJECTIVE WATERSHED PLANNING OF A DEGRADED URBAN RIVER Sean S, Wiedel and Patricia S, Wemer The North Branch of the Chicago River watershed is a largely urban watershed covering approximately 100 square miles, Three tributaries form a long, narrow watershed that originates in Lake County and flows into Cook County. The p,imary problems in the North Branch watershed are degraded water quality, flood damage, and loss and degradation of natural resources, all of which have led to a negative perception of the river, The Lake County Stormwater Management Conunission (SMC) joined with the Friends of the Chicago River (Friends) in a unique partnership to develop a multi-objective watershed management plan for the North Branch in Lake County. This planning effort is part of an overall watershed restoration strategy funded by a Clean Water Act Section 319 grant from the Illinois Environmental Protection Agency (lEPA) to the Friends and by local cost.share match, Planning for lhe North Branch watershed has been complic"td ;" " large number of jurisdictions and numerous stakeholders in the watershed. AB part of the planning effort, SMC has performed a ,ur;swntial amount of outreach to potential stakeholders. Development of a multi-objective plan is the most effective way for SMC to incorporate this wide variety of interests and concerns into a meaningful and useful product. T () address urban watershed problems, the watershed plan includes an action plan that recommends specific best management practices and projects that provide multiple benefits, These benefits include improved water quality, reduced flooding, new recreational opportunities such as greenways and trails, and protection and enhancement of wetlands and threatened and endangered species, The focus of the best management practice projects is on remediation and retrofits of existing problems caused by the urban nature of the watershed. THE TRINITY PROJECT: A MULTI-OBJECTIVE MEGA-PROJECT FOR DALLAS, TEXAS Walter E, Skipwith, p, E" Albert H. HaIff, p, E., Ph,D. and Jose I. Novoa, p, E, Dallas is in the planning stages of a $1 billion project to change the Trinity River from an under- appreciated, single pwpose floodway to a World Class Urban Greenbelt. The existing floodway has been tremendously successful over the years in preventing flood damages to the $ 15.4 billion in property protected by the existing levees. However, the very straight, austere ,~hannel and levee system has become the focus of attention recently because of an alamting trend of reduced flood protection due to flood plain development throughout the watershed and a lack of necessary maintenance downstream of the floodway. In addition to the physical barrier presented, the river and floodway cut the city in halffrom a social standpoint, being the demarcation between the relatively a\l1uent North Dallas neighborhoods and the economically depressed southem sector, Progress has been achieved in recent years to reverse the decline of the Floodway and Trinity River in Dallas, Some components of the ultimate flood protection system, the Rochester levee and the Central Wastewater Treatment Plant levee have been constructed. From the planning standpoint, steps have been taken towards the goal of re-configuring the Trinity River as the gr=:t "heart" of Dallas. The recommendations of the Texas DOT's Major Transportation Investment Study for a Trinity Parkway were recently adopted by the Dallas City Council, as was the Corps of Engineers concept ~Jr a chain of wetlands and new levees along the river through southern Dallas to provide much needed flood control. Other projects, such as It proposal for the Great Trinity Forest PaIt and a system of trails along the corridor were prepared and also adopted by the COWlci!. The Upper Trinity River Feasibility Study, an effort of the Corps of Engineers on behalf of several local cities including Dallas, is developing floJd control alternatives to reduce flood risks in the Dallas Floodway. However, it is yet to be well defmed as to how all of these efforts will relate to economic development and redevelopment along the corridor,