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09/15/2005 - City Council Public Works Committee13 AGENDA PUBLIC WORKS COMMITTEE MEETING SEPTEMBER 15, 2005 5:15 P.M. EAGAN CITY HALL ENGINEERING CONF. ROOMS lA & All L AGENDA ADOPTION IL REVIEW LEBANON HILLS REGIONAL PARK STORM WATER MANAGEMENT PLAN III. OTHER BUSINESS TV. ADJOURNMENT r PUBLIC WORKS COMMITTEE MEETING THURSDAY, SEPTEMBER 15, 2005 5:15 pm LEBANON HILLS REGIONAL PARK STORM WATER MANAGEMENT PLAN Backe round City staff are aware of a 40 year history of drainage concerns with the Lebanon Hills Regional Park (LHRP). The concerns primarily focus on the flooding of Cliff Road and Lakewood Hills Road, a private street, which closes all access to the Lakewood Hills neighborhood. Additional. concerns include the impact to individual septic system drain fields, loss of trees and the potential for flooding of residences. Current city staff pressed the Dakota County Parks Department to address the flooding concerns by addressing drainage within LHRP about 1985. At that time, the County Board adopted a policy that all drainage within LHRP would be addressed within LHRP without the use of a typical storm sewer system or connection to the City of Eagan's storm sewer system. The City of Eagan had approved a Stormwater Management Plan in 1984 that had included addressing the drainage within LHRP and continued to construct the storm sewer system throughout the city accordingly. During the late 1990s, County staff contracted a consultant to create a drainage management plan that would function internally to LHRP. Prior to the County's acceptance of this plan, the July 2000 Storm was unleashed on Eagan and LHRP, resulting in the flooding of Cliff Road and Lakewood Hills Road, as well as numerous other locations within the city. The County expended about $1 million in an attempt to address the flooding, but was ordered by the Minnesota Department of Natural Resources (DNR) to remove all flood mitigation efforts within the park due to environmental impacts. The County expended an additional $1 million in the restoration efforts directed by the DNR. In the past five years, three incidents, including the July 2000 Storm, have occurred requiring extensive pumping of drainage from LHRP in to the Eagan storm sewer system in order to protect private property from the previous listed concerns. County Parks staff has contracted with another consultant in the past few years to prepare a storm water management plan that would properly address the drainage concerns within and downstream of LHRP. With the direction to develop an ecologically appropriate plan to address the storm water management problems of the past, the consultant has extended their analysis beyond the limits of the park boundary. With the recent frequency of drainage issues with LHRP, members of the Lakewood Hills neighborhood have expressed their frustration with the lack of resolution to this long term problem to both city and county officials. Recent development within the southeast corner of Eagan, which drains in to LHRP, has heightened the concerns of the residents and increased the City Council's awareness of the LHRP drainage issue. As a result, the Council conditioned the approval of a portion of this development upon the approval of a storm sewer improvement to address these drainage concerns. On July 6, 2004, the City Council approved Project 905, Long Acre Outlet/Lebanon Hills Regional Park Storm Drainage Improvements, consisting of the construction of storm sewer improvements in southeast Eagan. The improvements will provide the managed delivery of drainage from southeast Eagan (Long Acres development/Gun Club pond) into and through LHRP by way of Marsh Lake and McDonough Lake to the public storm sewer system at Pond LP -51 and the Holland Lake lift station. The project will address the drainage needs of LHRP's drainage outlet in the area northwest of McDonough Lake, near Cliff Road. The approved project includes all of the basic improvements detailed in the feasibility report and the following upgraded improvements: Driveway Improvements adjacent to Pond LP -51, Marsh Lake Pipe Outlet (alternate), Connection to Wetland 121. As the majority of the improvements and construction activity are proposed to occur within LHRP, the approval of the Dakota County Board and Metropolitan Council will be required for the construction of Project 905. Since the approval of the project by the City Council, staff members from the following agencies have been holding stakeholder meetings consistently to coordinate compliance between the project design and Dakota County Park's Lebanon Hills Storm Water Management Plan. The cities of Apple Valley, Eagan and Rosemount; Dakota County Parks; Minnesota Department of Natural Resources; Vermillion River Watershed Joint Powers Organization; Gun Club Lake Water Management Organization. The draft Lebanon Hills Storm Water Management Plan was presented to the Dakota County Physical Development Committee on July 26, 2005. At their August 2 meeting, the Dakota County Board approved the release of the draft plan for public comment with the review period extending from August 2 -September 30. The plan includes the discussions and consensus developed via the mulit-agency stakeholder meetings. County Parks Department staff held an open house to present a summary of the draft Plan and address any questions or comments from the public at the Lebanon Hills Visitor Center on September 7. Plan Roviow The recommendations of the draft Lebanon Hills Storm Water Management Plan are summarized as follows (and available for detailed review if so desired): • Project 905 Construction . Area: As Project 905 is proposed to follow an alignment that includes three LHRP water bodies and overland or piped drainage within the park, it is appropriate to ensure the Project and Plan comply with each other. The following improvements are comparable to the Project 905 improvements. o Replace culvert outlet of Gun Club Pond (LP -23), include 10" orifice L- o Lower Marsh Lake 2', from 905.3 to 903.3 Q' o Storm SewerBio-swale connection from Marsh Lake to McDonough Lake / o Build berm at McDonough Lake to 889.0 for flood protection o Maintain McDonough Lake (summer level), Structure Control Elevation 879.2 o Gravity Storm Sewer connection from McDonough Lake to LP -51 Lift Station o Valve Pipe connection between McDonough Lake & Wetland 121 o Excavate Wetland 121 to enhance infiltration o Replace & Upgrade LP -51 Lift Station o No Design Discharge to Holland Lake • Project 905 Associated Improvements: The following improvements are associated with the construction activities related to Project 905, primarily a result of the flood control improvements (berming) at McDonough Lake. o Raise access road to Lebanon Hills Visitor Center o Replace bituminous trail with raised boardwalk (McDonough Lake) o Construct additional trail along north & east side of McDonough Lake o Shoreline Bioengineering (McDonough Lake) o Winter Aeration System (McDonough Lake) o Replace 27" culvert w/ 15" culvert between Schulze Lake & McDonough Lake d yC • 120d' Street Improvements: 120"` Street adjacent to LHRP is located on the boundary of Eagan and Rosemount and said maintenance responsibilities are accordingly shared between the two agencies. The following improvements are related to the satisfactory operation of the Project 905 improvements. o Raise 120d' Street 2'+ for about 1400' (Total in 3 locations) o Replace & Add culverts Internal LHRP Improvements: The following improvements are inside LHRP and outside of the Project 905 construction area, but related to the satisfactory operation of the Project 905 improvements. o Cattail Lake Outlet o O'Brien Lake Outlet o Portage Lake Outlet o Bridge Pond Outlet o Valleywood Golf Course Pond Outlet • EaLan Stormwater Mana}=ement Plan: The following improvements are included in the City of Eagan's current stormwater management plan. 0 12" culvert from Pond 40(LP-7) to Jensen Lake o Pre-treatment sedimentation basin (Jensen Lake) o Bulkhead 21" storm sewer (south of Steeplechase) Gerhardt Lake/Wheaton Pond: The following improvements are a revision of the City of Eagan's 1990 Stormwater Management Plan, but comply with the current watershed management organization boundaries. o Wheaton Pond connection to Apple Valley storm .sewer system 0 6" culvert from Gerhardt Lake to Pond 11(BLP-3) Additional staff comments follow regarding the draft Plan. 1. The recommended improvements are prioritized in the Plan, however recommended responsibility/ownership for each option is not identified. The Plan should suggest how responsibility is to be determined. 2. Improvement costs are identified, but revenue sources are not stated. The Plan could state the positions expressed by the various agencies in the multi -agency stakeholder meetings and the expected revenues for each project based upon the agencies' associated responsibilities. This should also include the appropriate reimbursement of Eagan's downstream trunk storm sewer costs. The Plan can detail County Parks staff's disagreements with each city's expected financial contributions, as appropriate. 3. The Plan should recommend how to proceed to implement said improvements. The Plan should recommend a process for each improvement including the basis for design, ownership of the different options, cost responsibilities, schedules and executing agreements between agencies. Finance Oi)tion Ideally, the financing of the improvements proposed as a part of the draft Lebanon Hills Storm Water Management Plan would be shared by the agencies managing the park; Dakota County and the Metropolitan Council. From the perspective of the drainage areas impacting LHRP and the downstream areas, it is evident that multiple agencies, including the City of Eagan, could share in the funding of the Plan improvements. Based upon the City of Eagan's design and construction of a storm sewer system including the capacity for the LHRP drainage, it is also apparent that reimbursement of these incurred expenses, i.e. storm sewer trunk fees, is appropriate. One cost share approach discussed as a part of the multi -agency stakeholders meetings that appears to be favored by County staff is to collaborate and request $3,000_0gQJ!_'_Q0k state bonding to construct the planned storm water improvements included as part of Project 905. State or regional benefits include: • benefits several state water bodies • protects a DNR Trout Lake (Holland Lake) • stops flooding of private property • stops flooding of a major arterial (Cliff Road) that connects to State Highway 3 • protects public recreation and natural resources of a regional park. This shared bonding request could possibly include all agency stakeholders (Eagan, Apple Valley, Rosemount and Dakota County) which would broaden the legislative and constituency base. SUMMARY The draft Lebanon Hills Storm Water Management Plan incorporates drainage improvements throughout the Lebanon Hills Regional Park. Since a large majority of the drainage exits the park through McDonough Lake and Wetland 121 and ultimately enters the City of Eagan's storm sewer system at this point, it is very important that the city's Project 905 is compatible with this plan. As much of the remaining area within LI -IRP also drains into the Eagan storm sewer system and portions of Eagan drain into LHRP, it is crucial that the City of Eagan can support the final version of the plan and its eventual implementation. As presented in the draft Lebanon Hills Storm Water Management Plan, the recommendations are acceptable as staff has found them to be primarily consistent with the City of Eagan`s Stormwater Management Plan and Gun Club Lake Watershed Management Organization boundary. While staff has some differences in opinions with some of the recommendations on a technical basis, the insight of the multi -agency stakeholders meetings and the comprehension of the ecological focus of the Plan adequately mitigate these differences. Specifically with regards to Project 905 and the Storm Water Management Plan, the multi -agency stakeholders group has developed consensus on a technical plan that has been incorporated in to the LHRP Plan. That being the case, the determination of an appropriate cost sharing approach must follow. The County Board's approval of the Lebanon Hills Storm Water Management Plan is required in order to proceed with this effort and move towards construction of Project 905. If 2006 state bonding is secured, as explained previously, Project 905 could begin construction possibly in the late summer or early fall of 2006 (if construction plans were prepared concurrent with the legislative session). If state funding is not secured, an alternative cost share approach would have to be determined after the session, with the construction schedule established accordingly. PUBLIC WORKS COMMITTEE RECOMMENDATIONS: 1. Recommend the City Council's support of the draft Lebanon Hills Storm Water Management Plan, including directing staff to prepare a letter of support for the draft Plan to the Dakota County Parks Department accompanying suggestions for minor revisions or additions; OR 2. Recommend the City Council direct staff to prepare a letter of opposition to the draft Plan to the Dakota County Parks Department accompanying suggestions for significant revisions or additions.