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C. Minnetonka Middle School Well Project Update CITY OF CBANHASSEN 7700 Market Boulevard PO Box 147 Chanhassen, MN 55317 Administration Phone: 952.227.1100 Fax: 952.227.1110 Building Inspections Phone: 952.227.1180 Fax: 952.227.1190 Engineering Phone: 952.227.1160 Fax: 952.227.1170 Finance Phone: 952.227.1140 Fax: 952.227.1110 Park & Recreation Phone: 952.227.1120 Fax: 952.227.1110 Recreation Center 2310 Coulter Boulevard Phone: 952.227.1400 Fax: 952.227.1404 Planning & Natural Resources Phone: 952.227.1130 Fax: 952.227.1110 Public Works 1591 Park Road Phone: 952.227.1300 Fax: 952.227.1310 Senior Center Phone: 952.227.1125 Fax: 952.227.1110 Web Site www.ci.chanhassen.mn.us ~ ...,..,.At1 .-r# MEMORANDUM TO: Todd Gerhardt, CiJy Manager I Paul Oehme P.E., Dir. of Public Works/City Engineer I I I March 24,2008 ! o. <1 FROM: DATE: 6~' I ! I Minnetonka Middl~ School Well Project No. 08-08: I I I I I Update SUBJ: BACKGROUND. On February 25,2008, staff updated the Council on the progress for upgrading the. well on the Minnetonka West School property to a municipal production well. On March 14,2008, staff met with the Minnetonka School District representative to continue to discuss the potential for improvements to the school well. On March 18,2008, staff held a neighborhood meeting. DISCUSSION Wells 12 and 13 Update As you are aware, the City lost the use of two water supply irrigation pumping last summer. Currently,theCityi~.int new wells, Wells 12 and 13, to replace the 10stwellp~()ul.1 started and is anticipated to be completed in6 t09\yee!<'s; improvements scheduled to start the week of March.17,2()O between 3 to 5 weeks to complete dependingonwM~l1~r Minnetonka West Middle School Well Background Staff has been working on the possibility ofconvertingthe<J;it Middle School well into a municipal well. Theschoolwellinl>/ ent is proposed to.add additional capacity to the system needed tomeetdeman~in the short term from new developments coming on line such as the ChanhasseIll1igh School. The school well was drilled in 1963 before the current welFcoue wasirrfol' turned over to the City in the 1970's after the school hooked up to City he pump and motor currently in the well can only pump250 gallons per minute (gpm) and does not have the required chemical treatments available to pump into the distribution system. The City test pumped the well last fall to determine if it could yield more than the current 250.JgpJ.119~pacity. Alsoi;in conjunction with the test pumping, Barr Engineering completed a groundwater model of the west well field to identify any well field interference issues. Based upon this information, it was The City of Chanhassen . A growing community with clean lakes, quality schools, a charming downtown, thriving businesses, winding trails, and beautiful parks. A great place to live, work, and play. Todd Gerhardt Minnetonka Middle School Well Project Update March 24, 2008 Page 2 determined the well could yield between 700-800 gpm with no interference issues. The aquifer into which the well is constructed could yield more, however, there is a 6" casing at the bottom of well which limits the yield of this well. The City discussed the possibility of making improvements to the school well with the School District last fall. The City also received a preliminary evaluation of the well from a well contractor last fall regarding redeveloping the well. Staff met with the Minnesota Department of Health (MDH) and explained the City's water needs to them and asked permission to make modifications to the school well and use it as a regular well during peak demand days. On February 4, 2008, the MDH commented on staff's request. Unfortunately, the well was not constructed to current well code requirements and it would be very difficult and expensive to have this well fixed to comply with current well code. However, the MDH did say it tentatively would give the City permission to use the well for backup or peaking under certain conditions. The tentative conditions set forth by the MDH on the use the well are as follows: 1. A complete water quality analysis test must be completed and water quality results must meet the Safe Drinking Water Act. 2. The well must be located at least 50 feet from potential sources of contamination as specified in Minnesota Rules Chapter 4725. A well site survey by a representative of the Minnesota Department of Health must be conducted. 3. The well owner must obtain an appropriations permit from the Minnesota Department of Natural Resources. 4. A preliminary wellhead delineation worksheet must be completed for this well and submitted to the MDH for review. 5. The well owner must provide written documentation that they own or legally control all land within 50 feet of the well. The City would need to obtain an easement from the School District for this requirement. The easement would have a sunset clause. 6. A copy of the downhole camera videotape must be provided to the MDH for reVIew. 7. After December 31,2009, the well will not be allowed to be used as a community water supply well to meet average day demands. If the City would like to keep the well as an "emergency back-up" well, then the MDH will allow this designation until the year 2012. By December 31,2012, the well should be sealed in accordance with Minnesota Rules Chapter 4725. G:\ENGIPUBLIC'L2008 Projectsl08-08 School Well No. 141bkgd 032408 Council worksessioll.doc Todd Gerhardt Minnetonka Middle School Well Project Update March 24, 2008 Page 3 8. The MDH may revoke the approval to use this well if the well is found to be vulnerable to contamination during the time period specified, or if the property ownership or legal easement changes. If the school well would have improvements made a new well should be planned for in the near future to replace the school well. The new well would be able to utilize a majority of the infrastructure installed to connect the school well to the distribution system. The proposed plan is to connect the school well to the City's system by direct boring a raw watermain from the school well to Well No. 7 located at the comer of Lake Lucy Road and Lake Harrison Circle. The raw watermain would be placed on the site where a new well could be drilled in the future. The water from the school well will receive chemical treatment at Wellhouse No.7 and then be directed down to the low zone system via an existing raw watermain pipe intended for future use as a water supply main for the proposed west water treatment plant. The project would also include manual valving improvements which would allow the treated water to be directed into the high zone if the need arises. The electrical system serving the school well and most of the raw water piping would be sized so that it could be used by the anticipated future replacement well and so would not be lost once the school well is abandoned and sealed. Minnetonka West Middle School Well Update Since the last time staff gave Council an update on this school well, several items have been worked on. . ,Staff met with the Minnetonka School District on March 14,2008 to discuss the well. The School District stated they are willing to work with the City on the school well and future new well improvements. Their main concern is granting a 50' easement around the well until 2012. The School District is planning to expand the kitchen and lunch room facilities in 2011 and would like the easement around the well to expire by 2011 if the lunch room project moves forward. The school did not think it would be an issue to construct a permanent well south of the school properly and have access through the school property. Approximately.l acre of land would need to be acquired from the school district and a right-of-entry would need to be approved by the School District. The School District did not think the acquisition or granting a right-of-entry would be an issue. . A complete water quality analysis test for the school well will be completed by the Minnesota Department of Health at no cost to the City. This work should be completed in the next few weeks. The test well analysis is for VOC's, radionuclides, radon, TOC, nitrate and coliform bacteria. . A neighborhood meeting was held on March 18,2008 to discuss the proposed improvements. Two residents from the area attended the meeting. The property owners' concerns about the project included tree loss due to the G:\ENGIPUBLIC\_2008 Projects\08-08 School Well No. 14\bkgd 032408 Council worksessioll.doc T odd Gerhardt Minnetonka Middle School Well Project Update March 24, 2008 Page 4 directionally bored watermain, construction noise, project length and construction working hours. Tree loss will be minimal because staff is proposing to directionally drill the raw watermain. However, the area around the future new well head will have to be cleared to construct the well but the area will be replanted. Working hours will be limited to City's approved hours which are 7:00 a.m. to 6:00 p.m. Staff is not anticipating work to take place on Saturdays. The project should take about 3 weeks to substantially complete, depending on the weather. . Staff has also looked into additional cost saving for the school well improvements. A new pitless adaptor, which is the connection point from the well to the raw watermain, will need to be installed however the adaptor would be able to be salvaged and reused on the new well. This would save approximately $10,000 on the project. Also, staff has looked at resale value of the pump and motor for the school well. Staff estimates that the City should be able to recoup 50% of the cost for the pump and motor at resale. The cost the City would not recoup for the equipment is estimated at $9,000. The only infrastructure that would not be reused by a new well is approximately 300' of 8" raw watermain pipe, and the electrical conduit pipe that would run from the electrical vault to the school well. Staff is now estimating the cost the City would not be able to recoup for the school well improvements is $45,000. If inflationary costs are calculated in with the infrastructure constructed this year versus if the improvements were to be constructed in 2011, the funds unable to be recouped are negligible. RECOMMENDATION Staff feels at this time the City can comply with the MDH requirements. The main issue is the request to cap the well by the end of 2011 by the School District. The school well would be used as a peaking well during high demand periods in the summer and would function primarily as a backup well throughout the remainder of the year. With respect to the requirements, staff feels the necessary improvements are cost effective even with the conditions set forth by the MDH and the School District, since the necessary improvements would be planned in such a way to allow for a future well to be drilled nearby replacing the school well. The improvements would give the City's water system added capacity, additional backup capacity in the event a well is lost and added redundancy to the system. Attachments: CIF Page Drawings c: Brian LeMon, Barr Engineering G:\ENGIPUBLICI_2008 Projectsl08-08 School Wen No. 141bkgd 032408 Council worksessioll.doc Capital Improvement Program City of Chimhassen, MN 2008 thru 2012 I Contact Project # W-045 Department Water System hnprovements Type Unassigned Useful Life I Project Name West Junior High School Well Account # 1 Account # 3 Category Utilities P.'iority nJa I Account #2 Total Project Cost $715,000 I Description I This improvement will convert the school well from a stand by well into a regular producing municipal well. Currently, the well can only produce 250 gpm. It is anticipated the well could produce as much as 800 gpm. The project consists of a new submersible pump and using some electrical components from well #5 that are anticipated to be decommissioned. A new water main is necessary to be extended to well #7 well house for chemical treatment. Valve improvements are also anticipated to have the ability to bleed this water out of the high zone pressure area. I Justification I I To meet the current water demand of the city. I I Expenditures Construction 2008 715,000 715,000 2009 2010 2011 2012 Total 715,000 715,000 I Total I Funding Sources Water Utility Fund 2008 715,000 715,000 2009 2010 2011 2012 Total 715,000 715,000 I Total I I Operational Impact/Other I I I I I I 132 I 25 0 ~ o Feet 25 50 75 , - BARR - Figure 1 School Well Site City of Chanhassen Chanhassen, MN