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Home My WebLink About20160314 UC Minutes UTILITY COMMISSION REGULAR MEETING MINUTES March 14, 2016 CALL TO ORDER Puxsuant to due call and notice thereof the regular Utility Commission meeting of the City of Rosemount was called to order on March 14,2016, at 5:31p.m. in the Conference Room of the City Hall, 2875 145`h Street West, Rosemount. President Speich called the meeting to order with Commissioners Connolly and McDonald,Public Works Director Wrase,Andrew Brotzler and Bill Alms (WSB), and Recording Secretary Kladar attending. ADDITIONS OR CORRECTIONS TO AGENDA None AUDIENCE INPUT None APPROVAL OF MINUTES Motion by McDonald. Second by Connolly. Motion to approve the minutes of the Febniary 22,2016 Utility Commission meeting. Ayes: 3. Nays: 0. Absent: 0. Motion carried. 5. OLD BUSINESS 5.a. Vermillion River Watershed Update Bill Alms and Andrew Brotzler from WSB &Associates were in attendance to present an overview of the hydrologic modeling report prepared pursuant to the Joint Powers Agreement with the Vermillion River Watershed Joint Powers Organization. Brotzler provided a historical overview of the City's stormwater plan. In 1998 the City's Stonnwater Management Plan was completed and it included four discharge locations to the Vermillion River. At that time the Plan discharge rate was 300 cfs for the 100 year- 24 hour event. In the late 1990's the Met Council was plaruiing for expansion of their wastewater treatment center. However,during ' that time the DNR designated the Vermillion River as a trout stream which resulted in new limitations for discharge rates and volumes to the Verniillion River. In order to increase capacity, the Met Council built the outfall pipe to the Mississippi River. The City updated its Stormwater Management Plan and a City Model was developed in 2002. 'This updated Plan included a proposed overflow pipe to the Mississippi River. In 2002 Dakota County took on watershed responsibilities through the Joint Powers Agreement that the City currently works under. 1 Alms noted that the City developed its current plan for an overflow to Mississippi River as well as increased reliance on infiltration. The 2007 Stormwater Plan has stringent developer requirements of 0.05 cfs per acre. The infiltration challenge is the west 1/3 city not developed with infiltration; there is intemuttent loss of infiltration during frozen conditions and non-infiltration soils on certain sites. The City has several watersheds and basins that currently have no outlet: Shannon Pond, Wachter L.ake,and Bloomfield Pond. In 2013 the City sent a letter to the VRWJPO requesting consideration to direct stormwater overflows for e�reme events south and east through Empire and Nininger Townships to the Vermillion River. As their original model did not include Rosemount,the VRWJPO indicated that an update would be needed to the Vernullion River hydrologic model to deterniine if an intercommunityflow standard would be required at the four proposed discharge locations and the potential downstream impacts. Regarding the modeling methodology,Barr Engineering stated that the critical event for the Vermillion River Watershed is the 4-Day Atlas 14 rainfall event. The 4-Day event becomes a critical event across watershed as a whole. Alms noted that the model was based upon Rosemount as it stood in 2005. The watexsheds that were modeled were generally 160 to 640 acres and the model doesn't consider freeboard or structure impacts. Alms identified the landlocked subwatersheds with four discharge points located. Comparing to the 1998 plan at Shannon it is proposed that city needs 30-46 cfs to provide flood protection. The outlet off Biscayne would account for overflows from Erickson and Wachter totaling 250-300 cfs. The third location showed 150 cfs out of the southeast corner of the City and the fourth location showed 350 cfs to handle low points from Flint Hills and UMore. Alms raised the following outstanding issues: Will regulatory approvals be received to increase discharge rates to Verniilion River? The City would need to request change in intercommunity flow rate standard. Watershed district staff has expressed interest in working with Rosemount on this request but there are other entities involved(VRWJPO,NIl'CA,DNR,Empire). Who will maintain the cross jurisdictional conveyance systems? How will upsized conveyance systems be paid for? If all ponds are at management levels,the City has capacity to provide protection for 100 year event. However with sole reliance on infiltration and no overflow system, the recoverytime for flood protection is weeks or months. The problem would arise if Rosemount were to experience a second event. It was noted that the City can absorb a 100 year event. However,the level of protection that was built in years ago needs to be updated to Atlas 14 rainfall. Public Works staff has plans for interim protection in the event of the snowmelt. The interim solution includes pumping into farm fields. 2 General discussion regarding a significant rainfall event in 2001 which caused some flooding in developed areas. Brotzler noted that several stormwater lifts were not in place the time of that event. Alms noted that while we may have seen events close to 100 year rainfall we haven't seen a 10 day snow melt event. The recommendations include: development of an existing conditions model;presenting a detailed request to VRWfPO Board for proposed outlets to Vernullion River for review and evaluate conditions of discharge received by VRWJPO against other options to provide required property protection. Wrase noted that VRWJPO seems willing to help Rosemount find a solution and work with Empire. A likely solution would be to convey the required discharge across the road(CDSAH46) and release to a new pond in Empire that would reduce the 100 year discharge at the acceptable rate indicated in the modeling of 8 cfs during the 100yr event.. The pond would be built and paid for by Rosemount. Alms noted that was a realistic objective to achieve rather than a conveyance direct to the Vermillion River. The ne�ct step is to begin the updating the stormwater comprehensive plan documents and a City- wide S`Y�NIIVI Model and develop some conceptual solutions to present to VRWJI'O. Alms said he expects to see the wateYshed's plan finalized in June or July and the City has 180 days to adopt plan. Alms noted that the most cost effective solution will likelybecome clearer as the comp storm plan gets updated. 6.a. Set Meeting Dates 2016-2017 The proposed calendar was reviewed and there were no issues with the 2016-2017 Utility Commission dates. Motion by Connolly. Second by McDonald. Motion to approve the proposed calendar for the Utility Commission for 2016-2017. Ayes: 3. Nays: 0. Absent: 0. Motion carried. 7. PRESIDENT'S REPORT President Speich advised the Commission that this was his last meeting as he'd been appointed to the Parks &Recreation Commission. EXECUTIVE DIRECTOR'S REPORT 8.a. City Projects Update The attached project report was reviewed and Wrase provided a brief summary. The Danbury Way Improvement bids are in and a public hearing on assessments is scheduled for Apri119,2016. Bella Vista 4`h is a new development containing 15 single lots. The peer review of the 1.5 MG GST and Booster is scheduled to go before Council Work Session. Wrase advised that there was one 3 remaining parcel easement to be obtained in the Safe Routes to School project and eminent domain had been authorized. Well 4 has been cleaned out and inspected by DNR and the City should soon have a determination whether it can be converted to an observation well. Lastly,a draft of the East Side Utilities Study is available and there will be a future progress and comment resolution meeting with SE�L 8.b. 2016 Well Pumping Report The attached report was reviewed and it was noted that pumping was up for the second straight month. 8c. Set Next Meeting Agenda for April 18, 2016 No items were discussed for the next meeting's agenda. ADJOURNMENT There being no further business to discuss the meeting was adjourned by Speich at 6:27 p.m, Res ctfully submitted, � Karin Kladar Recording Secretary 4