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1999-06-01CITY OF MOUND CITY COUNCIL SPECIAL MEETING NOTICE is hereby given that the City Council will hold a Special Executive Session on June 1, 1999, at 6:30 P.M., prior to the Committee of the Whole Meeting which will begin at 7:30 P.M. The purpose of this change in time is to hold an Executive Session to discuss the Woodland Point litigation. COMMITTEE OF THE WHOLE MEETING AGENDA 1. Presentation by citizen group for a Westonka Community Center. 2. Drainage problem Halstead Lane/West Edge Blvd. Francene C. Clark, CMC City Clerk POSTED MAY 28, 1999 LAKER NEWSPAPER NOTIFIED JUNE 1, 1999 May. 26, 1999" IO'lgAM MCCOMBS FRANK ROOS ...... '" ....... ' ........... "No. 791g--P. 2/5' £ngineedng ° PlanniNg · Surveying May26,1999 Ms, Pat Meisel, Mayor City of Mound 5341 Maywood Road Mound, Minnesota 55364 SUBJECT: Dear Pat: City of Mound Halstead Lane/West Edge Boulevard Stoma Sewer MFRA #11379 This letter is a follow-up to our meeting with resident Kevin Beigler and then City Manager, Ed Shukle, regarding flooding problems on Mr. Beigler's property at 2820 Halstead Lane. Myself and mother engineer from our office made another trip to the site and conducted an inspection of the complete system fi:om the storm sewer outlet in the wetlands west of Halstead Lane to the beginning of this drainage area at Beachwood Road and West Edge Boulevard. We also obtained copies of the original surveys from the property jackets that were used when build/ng permits were issued for the Beigler property and also the three lots on the north side of Pine Road between Halstead Lane and West Edge Boulevard. A few more facts have come to li~t that may help to explain why there is a problem with this storm sewer system. I was also very concerned about the sinkholes on Mr. Beigler's propert7 after watching the videotape of the 1995 rain event. The closed storm system from the inlet on the Beigler property to the outlet in the wetlands west of Halstead Lane does not appear to be of sufficient size to accommodate the mn-off under present conditions. At the time, this system was installed when Woodcrest was developed in the early i970's, West Edge Boulevard did not have curb and gutter or catch basins. As part of the 1980 Street Improvement project, concrete curb and gutter and storm sewer was installed in West Edge Boulevard. The culvert under West Edge Boulevard at the lot line between Lots 11 and 12, Block 2, Westwood was replaced with catch basins and a storm sewer line which discharges into the same swale where the old culvert outlet ',,,'as located. At that time, the only house of the four in question to exist was the home on Lot 12, 2879 West Edge Boulevard, PID 23-11%24 32 0030. The other three homes were built between 1982 and 1984. The improvement of West Edge Boulevard, with the 15050 23rd Av,nue North · Plymouth, Minnesota · 55447 phone 612/476-6010 · fax 61Z'476-$532 Max. 26. I999 I0:20^~ Ms. Pat Meisel, Mayor May26,1999 Page 2 I~{CCOMSS F?,:<N}i !005 ...................... No. 79!? ?. 3/":.,' addition of curb and gutter and storm sewer, directed all the street run-offto this system. Previously, much of the rainfall was absorbed or ran to other areas before it could reach the swale between Lots 11 and 12. The elevations at which the storm sewer inlet on the Beigler property and the Beigler home itself were btfilt at, also add to the problem. The storm sewer inlet was installed approximately two feet higher than the design grade as shown on the development plan for Woodcrest of Mound. In addition, the survey used for the building permit on the Beiojer home did not show the existing storm sewer and has different proposed elevations Ibr the house then what was actually built. Storm sewer systems such as this one, with inlets in rear yards, should have emergency overflows below any openings into structures. The imended overflow for this system has a number of obstructions, such a~ bushes and a large clump of trees at the curb llne. The threshold of the patio door on the Beigler home is well above the storm sewer inlet, but it is only a couple of inches higher then the top of the curb at the intended overflow. The overflow elevation at the street should be 6 to 12 inches below any door opening in adjacem homes. The area of the outlet for this system is also in need ofmajpr repairs and maintenance. Twenty-five years of silt deposited ar the flared end section has resulted in large delta, which restricts the flow into the wetland. This area needs to be cleaned out and riprap added at the apron. 'Ilae only complete solution that we see for thi~q flooding problem is to replace the existing storm sewer system with larger pipe and at the same time emend the storm sewer to the catch basins in West Edge Boulevard. This will put the flows from West Edge Boulevard in a closed system and eliminate the erosion problems now experienced between West Edge Boulevard and the inlet on the Beigler property. An additional catch basin should be added to the west curb line on West Edge Boulevard, which will help to eliminate the problem of water overflowing the curb in larger rainstorms. A section of street at the catch basins in Halstead Lane will need to be removed to allow the curb lines to be lowered six to eight inches, which will provide the necessary emergency overflow. At a minimum, the large clumps of trees behind the east curb line must be removed and the overflow swale regraded, Replacement of the storm sewe~ from Halstead Lane west to the outlet is a problem because of the number of large trees growing in the easement, some of which may be over the existing pipe. At least two, possibly three, bill need to be xernoved. Some regrading of this area will also be necessary to eltminate an erosion problem next to the foundation at the back portion of the home on the north side (Lot 8. Block 6,2811 Halstead Lane). At the present time, if the catch basins in Halstead Lane cannot accommodate a larger rainstorm and the street overflows, it runs next to the house instead of in a swale within the drainage easement. May 26. ~9g,~ !l~"~l:¢M Ms. Pat Meisel, Mayor May 26, 1999 Page 3 Except for one small area, the existing permanent utility and drainage easement~ are sufficient for the new lines; however, temporary, construction easements may be required to allow working space for the contractor during the eonslruction. The problem of the sinkholes could be handled ',','hen the storm sewer pipe is replaced. They need to be filled to eliminate future erosion. The issue of how to pay for the reconstruction of this storm sewer system also needs to be addressed. The drainage area of this system covers approximately 9.2 acres, which includes all or a portion of 27 lous and some School District property. It would be very difficult to assess a project such as this on a basis of drainage area and be able to justify the assessment. As an alternative, we would suggest a meeting with the six property owners adjacent to the proposed construction and directly affected by the situation. Methods of financing and cost sharing could then be discussed at tiffs meeting. Enclosed is a cost estimate to replace ar, ri extend thc present storm sewer as previously suggested. It also includes the excavation required to clean out the sediment deposit and create an open swale at the outlet ' ' ~' system. cna ot ,tie . If you have any questions or need additional i~brmation, please contact us. truly yours, McCOMBS FR_~NK KOOS ASSOCIATES, INC. John Cameron, City Engineer JC:pry Enclosure cc: Fran Clark, Acting CiD' Manager, City of Mound ¢.',maia:",l 1379km¢is¢~5-g5 ,ggg 10 22AM' 'MCCOI4Bg F. ^i K ..... No. 7glg~?. 5/5' COST ESTIMATE HALSTEAD LANE/WEST EDGE BOULEVARD STORM SEWER ITEM .UNIT UNIT COST Tree and Brush Removal Lump Sum $ 2,000.00/LS Bituminous Removal 300 SY $ 3.50/SY 15' RCP 70 LF $ 30.00FLF 18" RCP 160 LF $ 35.00/LF 21" RCP 75 LF $ 50.00/LF 2~t" KCP 130 LF $ 60.00/LF 24" Apron with Trash Guard 1 EA $ 1,000.00/EA Manholes 2 EA $ 1,500.00/EA Catch Basin Manhole 1 EA $ 1,500.00/EA Catch Basin 1 EA $ 1,200.00/EA Reconstruct Existing Catch Basin 2 EA $ 500.00fEA Riprap 10 CY $ 75.00/CY Remove and Replace Curb and Gutter 150 LF $ 25.00/LF Class 5 Gravel 100 TN $ 12.00fI'N Bituminous Base (2") 35 TN $ 45.00/TN Bituminous Wear (1-1/2") 25 TN $ 50.00/TN Sod 600 SY $ 4.00/SY Seed and Mulch Lump Sum $ 500.00/LS Remove Sediment at Outlet 40 CY $ ' 25.00/CY Contingencies (I 0%) Total Estimated Construction Cost Engineering, Legal, Fiscal & Administrative Cost (35%) Total Estimated Cost TOTAL 2,000.00 1,050.00 2,100.00 5,600.00 3,750.00 7,800.00 1,000.00 3,000.00 1,500.00 1,200.00 1,000.00 750.0O 3,750.00 1,200.00 1,575.00 1,250.00 2,400.00 500.00 1,000.00 $ 4,275&Q $ 46,700.00 $ 16,300.00 $ 63,000.00