The URL can be used to link to this page

Home My WebLink About6.l. Receive Feasibility Report/Approve Project/Order Plans & Spec's - Hawkins Pond Lift Station & Forcemain, City Project #328CITY OF ROSEMOUNT EXECUTIVE SUMMARY FOR ACTION CITY COUNCIL MEETING DATE: May 15, 2001 AGENDA ITEM: Receive Feasibility Report /Approve AGENDA SECTION: Project /Order Plans & Spec's- Hawkins Pond Lift Station & Consent Forcemain, City Project #328 PREPARED BY: Bret A Weiss, P.E., Interim City Engineer AGENDA NQ; L ATTACHMENTS: Resolution, Feasibility Report APPROVED BY: Attached please find a copy of the Feasibility Report for the Hawkins Pond Lift Station and Forcemain. This project was reviewed with the Utility Commission in April and a neighborhood meeting was held with the affected property owners on April 30t This lift station is anticipated to be under construction in 2001 with a completion in spring of 2002 for full operation. Plans will be developed to include the installation of the forcemain as soon as possible with pumps and controls installed as soon as they are available, likely in spring of 2002. Because the pump operations will not be started until 2002, the turf restoration around the pond will not be bid as a part of this project but will be bid separately in 2002. The turf establishment program that has been recommended to the Utility Commission and the neighborhood group involves a more natural wetland seed mix that will not be manicured to the waters edge. The turf will be a mixture that can survive under saturated conditions and will include wetland flowers and vegetation. RECOMMENDED ACTION: MOTION TO ADOPT A RESOLUTION RECEIVING THE FEASIBILITY REPORT, APPROVING THE PROJECT AND ORDERING PLANS AND SPECIFICATIONS FOR THE HAWKINS POND LIFT STATION AND FORCEMAIN, CITY PROJECT #328. COUNCIL ACTION: 2 CITY OF ROSEMOUNT DAKOTA COUNTY, MINNESOTA RESOLUTION 2001 - A RESOLUTION RECEIVING THE FEASIBILITY REPORT, APPROVING THE PROJECT AND ORDERING PLANS AND SPECIFICATIONS FOR THE HAWKINS POND LIFT STATION AND FORCEMAIN CITY PROJECT #328 WHEREAS, pursuant to the resolutions of the Council adopted on January 16, 2001, a report has been prepared by the City Engineer with reference to the improvement of Hawkins Pond Lift Station and Forcemain, City Project 9328, and this report was received by the Council on May 15, 2001, and WHEREAS, the report provides information regarding whether the proposed project is necessary, cost - effective, and feasible. NOW THEREFORE BE IT RESOLVED BY THE CITY COUNCIL OF ROSEMOUNT, MINNESOTA: 1. Such improvements are hereby ordered as proposed in the Feasibility Report for the project. 2. The City Engineer is hereby ordered to prepare plans and specifications for the making of such improvements. ADOPTED this 15th day of May, 2001. Cathy Busho, Mayor ATTEST: Linda Jentink, City Clerk Motion by: Voted in favor: Seconded by: Voted against: u C 0 aff MF r p cf� 'J Hawkins Pond Lift Station and Forcemain C ity Project Number :328 for the City of WSB Proj. No. 1324 -00 May 15, 2001 Submitted too City of Rosemount 2875 145th Street West Rosemount, Minnesota 55068 A 4150 Olson Memorial Highway Suite 300 WSB Minneapolis, MN 55422 763 - 541-4800 & Associates, Inc. FAX 763 -541 -1700 Feasibility Study for Hawkins Pond Lift Station and Forcemain Prepared for the City of Rosemount City Project No. 328 May 15, 2001 Prepared By: WSB & Associates, Inc. 4150 Olson Memorial Highway, Suite 300 Minneapolis, MN 55422 (763) 541 -4800 (763) 541 -1700 (Fax) City of Rosemount Feasibility Study for Hawkins Pond Lift Station and Forcemain City Project No. 328 WSB Project No. 1324 -00 May 15, 2001 Honorable Mayor and City Council City of Rosemount 2875 West 145 Street Rosemount, MN 55068 Re: Feasibility Report Hawkins Pond Lift Station and Forcemain Project City of Rosemount Project No. 328 WSB Project No. 1324400 Dear Mayor and Council Members: Earlier this year, the City Council authorized the preparation of a Feasibility Report for the construction of a lift station and forcemain outlet for Hawkins Pond. in accu dance with the Council's request, the report has been completed. We would be happy to discuss this report with you at your convenience. Please give me a call at (763) 287 -7190 if you have any questions. Sincerely, WS.B & Associates, Inc... Bret A. Weiss, P.E. President Enclosure Jam' Minneapolis • St. Cloud • Equal Opportunity Employer ' CERTIFICATION I hereby certify that this plan, specification or report was prepared ' by me or under my direct supervision and that I am a duly Licensed Professional Engineer under the laws of the State of Minnesota. c Bret A. eiss, P.E. Date: May 15, 2001 Lic. No. 20753 City of Rosemount Feasibility Study for Hawkins Pond ' Lift Station and Forcemain City Project No. 328 WSB Project No. 1324-00 j a3vd 00-PUT 'ON PaPAd MI SZ£ 'oAI Pafotd 413 mmmaatgi puv uoun ;S *7 Puod skWTH JO IfPMS 41pq.tsvag ;unowasog fo 4p SIaavd ..................... ............. .. sadnSzd g MpuaddV £I awa ................... .. ;soO fo uozuid0 V xrpuaddV ZIa .................. ............................... suoz ;npuatumoaag IIa .Svd .. .................. ....... .. ..... suo;snlauoO HIA OIa$vd ...................................................... alnpaVS IIA TA 6 a .8vd ............... ............................... s;zur.tad puv s ;uaurasv9 : g ...................... ffu;auvuzd a ..................... ............................... s ;so,7 pa;aaford AI a�vd ........ .............. ..................... s;uawano rdusl pasodo td 'III a2 ................. ........... puo,7 8 u;;szxd II -0 .8vd ... ......... ............................... ........ uoz;anpodMI I ,IMYMM12S 9AIJA,93Xd S.Lt191AT00 ,d0 97ffVJ ' 1 d9HS AVII VOIJI M93 7VIIINSATVffl .10 ff,71 97 J99HS 77111 ' slualuojfo a14vl L Introduction Hawkins Pond is located north of 145' Street and east of Davenport Avenue in the ' Hawkins Pond subdivision. City records indicate that the original small pond in this area was enlarged in 1996 to the current size with the sub - division development. The pond is landlocked at this time and there is a need to provide an outlet to control the water level. The lack of level control has created flooding problems in recent years. In response to this problem; the City Council authorized the preparation of this feasibility study to evaluate options for addressing the situation. The location of the existing Hawkins Pond and the watershed area are shown on Figure 1. City of Rosemount Feasibility Study for Hawkins Pond ' Lift Station and Forcemain City Project No. 328 WSB Project No. 1324 -00 Page 2 II. Existing Conditions The watershed area tributary to Hawkins Pond includes about 250 acres of residential development. At the normal water level of 912 feet above mean sea level, the pond has a surface area of about 4.27 acres, is generally four feet deep, and contains water throughout the year. The banks of the pond are grass covered and there is a tendency for the grass to die and expose the soil near the water level. The exposed banks are then subject to erosion. The existing pond is landlocked so water level reduction is entirely dependent on seepage or evaporation. The lowest top of bank elevation for the pond is on the east side at an elevation of about 928. Any water that overtops the bank at 928 is trapped in a low area just outside the defined pond area. The pond is surrounded by homes and the lowest floor elevation that was identified is about 931.5. There are about seven (7) homes with ' basement floor levels between 931.5 and 940.0. During July 7- 10,2000, the south metro area experienced a torrential rainfall event, with rainfall amounts of five to nine inches commonly reported. The highest reported rainfall was 11.33 inches in southeastern Eagan. The runoff from this rainfall event raised the water level in the Hawkins Pond to an estimated elevation of about 933 feet. During this period, the sanitary sewer lift station on the southwest side of the pond was flooded, and numerous homes constructed sandbag dikes to protect their basements. The water remained elevated until a temporary pumping system could be installed. The City of Rosemount has a significant, but variable easement around the pond. The easement extends to an elevation of about 930 feet, but the high water during the July, 2000 event exceeded the easement area and resulted in damages to private property. i City of Rosemount Feasibility Study for Hawkins Pond ' Lift Station and Forcemain City Project No. 328 WSB Project No. 1324 -00 Page 3 III. Proposed Improvements The City of Rosemount prepared a Storm Water Management Plan in 1997. Hawkins Pond is part of the overall city storm water management system and was part of the 1997 plan. The plan anticipated that a pumping station (lift station) would be constructed near the existing sanitary sewer lift station on the west side of the pond. The lift station will take water from the pond and pump it west to Diamond Path and then south into the gravity storm sewer system at County Road 42. The City has generally been following the Storm Water Management. Plan, and two segments of the required Hawkins Pond outlet force main (pressure sewer pipe) have been installed in conjunction with other projects. Approximately 550 feet of 12 -inch diameter pipe was installed from the edge of Hawkins ' Pond to the north right -of -way of 145t' Street. The existing pipe starts at a point about 140 feet south of the existing sanitary sewer lift station and extends from the pond to Davenport Avenue on an easement between Lots 9 and 10. The pipe continues south on Davenport Avenue and turns west about 60 feet just north of the existing curbing on 145' Street. The other segment that is in place was installed in 2000 with the Birger Pond lift station and force main project. The Birger Pond force main runs along the east side of Diamond Path from the southwest corner of Birger Pond to the north side of County Road 42. At 145' Street, a stub was provided for connection of the Hawkins Pond force main, and the main line was enlarged from a 16 -inch diameter pipe to an 18 -inch diameter pipe to accommodate the anticipated flow from Hawkins Pond. In order to complete the stormwater system for this area, the proposed improvements include the construction of a storm water lift station adjacent to the existing sanitary sewer lift station and extension of force main pipes to connect the two existing segments. In addition, some grading and vegetation improvements are proposed to stabilize and 1 protect the existing earth banks during the water level fluctuation. These proposed bank stabilization improvements are shown on Figure 2, and the proposed lift station and forcemain improvements are shown in Figure 3. A computer model of the Birger Pond watershed area was prepared to determine the p g p p appropriate pump size required to maintain reasonable pond water level during extreme ' conditions. The model indicates that a pumping capacity of about 3 cubic feet per second City of Rosemount Feasibility Study for Hawkins Pond Lift Station and Forcemain City Project No. 328 WSB Project No. 1324 -00 Page 4 1 (cfs) is required to control the pond levels. The model suggests that a 3 cfs outlet will provide the following water levels at the specified conditions. Condition Predicted Normal and High Water Elevation at 3 cfs Outlet Rate Normal water level 912 10 -year 24- hour rainfall event 100 -year 24 -hour rainfall event r 100 -year 10 -day snow melt event 923.5 929 The projected maximum water level is about 2.5 feet below the lowest identified basement elevation in the area. The proposed lift station will utilize a single, submersible pump with a control panel installed adjacent to the wet well. A single pump is proposed since there is significant storage area in the existing pond and there should be time to correct any pump problems before any flooding would occur. In addition, the station will be connected to the existing city remote monitoring system so notification of any problem will occur very quickly. A 24 -inch pipe will be installed between the lift station wet well and the pond. The pipe will be installed deep enough so that it will be under water during normal water level. A baffle structure will be constructed in front of the pipe to minimize any floating debris that may enter the pipe. Preliminary analysis indicates that a 35 Hp pump will be required to provide a 3 cfs outlet from Hawkins Pond. The capacity will be reduced somewhat to about 2.7 cfs during periods when the Birger Pond lift station pumps are also operating. This reduction is due to the back pressure generated by the increased flow rate in the shared portion of the force main south of 145' Street. Since both Birger Pond and Hawkins Pond have storage capacity, it may be possible to manually operate the two pumping sites to reduce the simultaneous operation and maximize the efficiency of each pumping station. The pump "start" elevation is manually set by the operator of the system. It is anticipated that the pump will be started at an elevation of about 913 feet or one foot above the normal water level. If the pump starts at 913 feet and there is no additional inflow into the pond, it will operate for about 17 hours to return the pond level to the normal water elevation of 912. City of Rosemount Feasibility Study for Hawkins Pond Lift Station and Forcemain City Project No. 328 WSB Project No. 1324 -00 Page 5 With this setting, in normal conditions, the water level will fluctuate only about one foot. However, during more extreme runoff conditions, the pond level will rise higher and the pump will operate longer. For example, during a 10 -year storm event, the predicted water level will reach about 918 feet and the pump will operate for almost 5 days to return the water level to 912 feet. r City of Rosemount Feasibility Study for Hawkins Pond Lift Station and Forcemain City Project No. 328 WSB Project No. 1324 -00 Page 6 r t IV. Projected Costs The anticipated total project cost for the proposed improvement is $357,600. This cost includes a 10% contingency factor and 25 % legal, engineering, administrative and fiscal factor. A detailed breakdown of the probable total project costs is provided in Table 1. City of Rosemount Feasibility Study for Hawkins Pond Lift Station and Forcemain City Project No. 328 WSB Project No. 1324-00 Page 7 i 1 V. Financing It is anticipated that the existing City Stormwater Utility Fund will be used to finance the proposed improvements. 1 City of Rosemount Feasibility Study for Hawkins Pond ' Lift Station and Forcemain City Project No. 328 WSB Project No. 1324-00 Page 8 VI. Easements and Permits Temporary easements may be required to install portions of the proposed force main pipe system, however, all permanent facilities will be installed within existing City easements or rights -of- way. The permits for this project will be required from the governmental agencies, having jurisdiction over the installation of the pond outlet. City of Rosemount Feasibility Study for Hawkins Pond Lift Station and Forcemain City Project No. 328 WSB Project No. 1324-00 Page 9 r i VII. Schedule In consideration of the effort involved, we anticipate that the proposed improvements can be accomplished under the following schedule: City Council Review Feasibility Study ............................ May 15, 2001 City Council Approval Feasibility Study and Authorize Preparation of Construction Plans and Specifications .................... May 15, 2001 Council Approve Project Plans and Specifications ..................... July 3, 2001 Open Bids (Lift Station and Forcemain) ......... ............. .... July 27, 2001 Award Contracts ............. ............................... August 7, 2001 Initiate Construction ...... .... ........ ....................... January 2002 Complete Construction ............ ............................... June 2002 Initiate Pump Operations ........ ................. ............ March 2002 *Bank stabilization/restoration will be bid and completed separately in the Spring of 2002. City of Rosemount Feasibility Study for Hawkins Pond Lift Station and Forcemain City Project No. 328 WSB Project No. 1324 -00 Page 10 VIII. Conclusions Based on the analysis and data included in this study, the following conclusions and recommendations are made: 1. The proposed stormwater lift station and force main are in accordance with the City's approved Stormwater Management Plan and the proposed system is feasible and the most cost - effective method of controlling the level of Hawkins Pond. 2. A single 3 cfs pump will provide water level control in the Hawkins Pond. 3. Water level control in Hawkins Pond is necessary to protect the existing homes that are adjacent to the pond. City of Rosemount Feasibility Study for Hawkins Pond Lift Station and Forcemain City Project No. 328 WSB Project No. 1324 -00 Page 11 ® IX. Recommendations It is the recomendation of WSB & Associates, Inc. that City Project No. 327 is feasible, necessary, and cost - effective from an engineering standpoint. We recommend construction of the proposed improvements as detailed in this report. City of Rosemount Feasibility Study for Hawkins Pond Lift Station and Forcemain City Project No. 328 WSB Project No. 1324 -00 Page 12 r Appendix A Opinion of Cost City of Rosemount Feasibility Study for Hawkins Pond Lift Station and Forcemain City Project No. 328 WSB Project No. 1324 -00 Page 13 n Schedule B Lift Station and Forcemain Table 1 - Opinion of Probable Total Proj C ost Schedule A Bank St a b ilization/Restoration Item Description Unit Est. Qty Unit Price Estimated Cost Unit Price Estimated Cost 1 Mobilization LS 1 $2,500.00 $2,500.00 $4,000.00 2 Excavation/Grading/Bank Preparation for CY 3200 $5.00 $16,000.00 $1,200.00 3 Erosion Control Mat (Elev. 911 to 922) SY 9100 $2.00 $18,200.00 $600.00 4 Seed - Wetland Mix (912 to 918) LB 60 $15.00 $900.00 $1,200.00 5 Seed - Sod Mix (918 to 922) LB 75 $8.00 $600.00 $1,600.00 6 Seeding AC 2.2 $250.00 $550.00 $3,200.00 7 Deciduous Shrub (Gray & Red Osier Dogwood) Shrub 365 $15.00 $5,475.00 $2,000.00 8 Deciduous Tree (Willow Plugs) EA 50 $5.00 $250.00 $5,400.00 9 Subtotal — Schedule A 12" DIP Forcemain $44,475.00 n Schedule B Lift Station and Forcemain Subtotal - Schedule B $215,700.00 Total Schedules A & B $260,100.00 Contingencies (10 %) $26,000.00 Indirect Costs (25 %) $71,500.00 Probable Total Project Cost $357,600.00 City of Rosemount Feasibility Study for Hawkins Pond Lift Station and Forcemain City Project No. 328 WSB Project No. 1324-00 Page 14 IM Item Description Unit Est. Qty Unit Price Estimated Cost 1 2021.501 Mobilization (2% Max.) LS 1 $4,000.00 $4,000.00 2 2104.501 Remove C &G LF 300 $4.00 $1,200.00 3 2104.505 Remove Bit. Pavement SY 300 $2.00 $600.00 4 2104.513 Sawing Bit. Pavement LF 400 $3.00 $1,200.00 5 Irregular Bit. Pavement SY 100 $16.00 $1,600.00 6 Bit. D/W Pavement SY 200 $16.00 $3,200.00 7 2501.515 24" RC Apron w/Trash Guard EA 1 $2,000.00 $2,000.00 8 2501.541 24" RC Pipe Sewer LF 60 $90.00 $5,400.00 9 2503.511 12" DIP Forcemain LF 1100 $38.00 $41,800.00 10 2503.602 Lift Station and Appurtenant Work LS 1 $120,000.0 $120,000.00 11 2503.602 Air Relief Manhole EA 1 $2,100.00 $2,100.00 12 2506.602 Connect to Existing 12" DIP Forcemain EA 3 $600.00 $1,800.00 13 2531.501 Concrete Curb & Gutter B618 LF 300 $20.00 $6,000.00 14 2563.601 Traffic Control LS 1 $5,000.00 $5,000.00 15 2573.502 Silt Fence - Heavy Duty Type LF 250 $3.00 $750.00 16 2575.505 Sodding - Type Lawn SY 3000 $2.00 $6,000.00 17 Temporary Pumping LS 1 $5,000.00 $5,000.00 18 Skimmer Structure w/Rip Rap LS 1 $8,000.00 $8,000.00 Subtotal - Schedule B $215,700.00 Total Schedules A & B $260,100.00 Contingencies (10 %) $26,000.00 Indirect Costs (25 %) $71,500.00 Probable Total Project Cost $357,600.00 City of Rosemount Feasibility Study for Hawkins Pond Lift Station and Forcemain City Project No. 328 WSB Project No. 1324-00 Page 14 IM 10 City of Rl j. S Hawkins Po 143RD STREET W. '�- 4:1 SIDE SLOP ELEV. 919 TO 10:1 SIDE SLOPE ELEV. 918 TO 919 r , t / 4:1 & B K E INT. ACCESS - C nt. Bench Herbaceous Wctland w/Shrubs Emergent Wetland Erosion Control Fabric Proposed Permanent Pool 4:1 (Typical Depth 1.3 ft) 10� 4: X 150 300 r t P6� �z �o z SECTION A -A Trail-Maint Bench Herbaceous Wetland w /Shrubs Emergent Wetland Erosion Control Fabric No Scale Proposed Wetland Vegetation Establishment Techniques: • Seedling impregnated fiber blankets (sedges,grasses) • Coconut fiber logs below N WL with live plugs • Willow posts/live stakes (willow & alder) 4:1 10:1 Proposed Permanent Pool (Typical Depth 1.3 ft) 4:1 SECTION B -B No Scale - 4150 Olson Memorial WSB Project No. 132400 Date: May 15, 2001 Highway Suite 300 Hawkins Pond Bank Stabilization /A /[ B Minneapolis, MN 55422 Yy - 763-541 -4800 &Aw"tarer, /ac. FAX 763- 541 -1700 Rosemount, Minnesota Figure 2 w:* 1275- 00*Hawkins*cad*BANK- STAB.dgn x 200 400 PROXIMATE EXISTING E8SEMENT 141RD -ST - 7 00YR-10DAY-HWL-929.0 —..IOOYR-24HR-HWL-923.2 Z 4 Z,11:�71 E 144th STREET Wf P SED LIFT STATIO EXISTING FO7RC 1454 STREE W. EXISTING STORM SEWER r PROPOSED FORCEMAINI r1 r CONNECT TO EXISTING STORMWATER FORCEMAIN o ( c } AT DIAMOND PATH �7 F _� � '� j�', �� s � I i h" t�'I �-� - 1� � - °�Z _ ? � -h � x'1'1 �_ � {� ' � n �, ` -- __ 11 I �'v-�' _ � VVSB Project No. 1324-00 Date: May 15, 2001 4150 Own Memorial Highway A Suite 300 Hawkins Pond Lift Station WSB Minneapolis, MIN 55422 763541-4800 & FAX 763-541-1700 Rosemount, Minnesota Figure 3 w:X1275-00*Hc)wkins*CGd*NWL-HWL.dgn v -4 DAVENPORTPA J v x 200 400 PROXIMATE EXISTING E8SEMENT 141RD -ST - 7 00YR-10DAY-HWL-929.0 —..IOOYR-24HR-HWL-923.2 Z 4 Z,11:�71 E 144th STREET Wf P SED LIFT STATIO EXISTING FO7RC 1454 STREE W. EXISTING STORM SEWER r PROPOSED FORCEMAINI r1 r CONNECT TO EXISTING STORMWATER FORCEMAIN o ( c } AT DIAMOND PATH �7 F _� � '� j�', �� s � I i h" t�'I �-� - 1� � - °�Z _ ? � -h � x'1'1 �_ � {� ' � n �, ` -- __ 11 I �'v-�' _ � VVSB Project No. 1324-00 Date: May 15, 2001 4150 Own Memorial Highway A Suite 300 Hawkins Pond Lift Station WSB Minneapolis, MIN 55422 763541-4800 & FAX 763-541-1700 Rosemount, Minnesota Figure 3 w:X1275-00*Hc)wkins*CGd*NWL-HWL.dgn