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Home My WebLink About9C - FIG Well Report CITY COUNCIL AGENDA REPORT MEETING DATE: AGENDA # PREPARED BY: AGENDA ITEM: November 5, 2001 9C Bud Osmundson, Public Works Director CONSIDER APPROVAL OF A REPORT REGARDING THE ADVISABILITY OF DEVELOPING A FIG WELL IN THE BROOKSVILLE HILLS AREA DISCUSSION: Historv As you are aware, we are in the final stages of the completion of Well and Pumphouse 'No. 6 on Wilds Parkway. We are also working on two additional fronts in an effort to provide more pumping capacity. Backf!round Weare trying to put additional wells in the Brooksville Hills area so that it keeps our options open for a centralized water treatment plant in the future, plus the fact that the Pumphouse for Well No.3 is set up mechanically to treat water from a third well (it currently treats water from Well No.3 and No.4), so we would not have to pay the cost of another pumphouse. Our Comprehensive Potable Water System Plan and our physical water system constructed to date, is built around the concept of the water being pumped from the Brooksville Hills area out to the city. The Comprehensive Plan always called for one well that would be used for peak periods somewhere on the other side of the lake, a condition now met with Well No.6. Two Fronts We are seeking authorization from the Department of Natural Resources (DNR) to drill and develop another Jordan aquifer well in the Brooksville Hills area by working with personnel from the Met Council and the DNR on geological modeling of the Jordan aquifer. We want to show through the modeling that an additional Jordan well in this area has little or no effect on the Savage Fen. The DNR has been reluctant to approve the city's request in the past because they were concerned that the well would impact the Savage Fen. The geological model is getting more and more refined and we are hopeful that a new Jordan well in this area will now show virtually no impact on the fen. We will be continuing this discussion and hope to come to an agreement in the next month. If the DNR is convinced that another Jordan well in this area has a detrimental effect on the fen, then it only gives the City two choices for future wells: either Jordan wells on the other side of the lake which will cause us to completely re- engineer the water system, or to drill Franconia, Ironton, Galesville (FIG) agenda considering initial report2 17073 Adelmann St. S.E., Prior Lake, Minnesota 55372 / Ph. (952) 440-9675 / Fax (952) 440-9678 AN EQUAL OPPORTUNITY EMPLOYER agenda considering initial report2 aquifer wells. The second front we are engaged in is to determine the feasibility of drilling a FIG well in the Brooksville Hills area. The advantage is the DNR is not concerned about this aquifer and is encouraging all area cities to consider it as an alternative water source to the Jordan, plus they have already stated that the city could drill a FIG well immediately. We have had Naeem Qureshi, P.E., of Progressive Consulting Engineers, Inc., to investigate the issues with drilling a FIG well. As a review, FIG wells are typically much lower in capacity and have different water quality characteristics than Jordan wells. Mr. Qureshi performed a quick analysis of area FIG wells in an effort to predict what we might expect if we drilled a FIG well. His report is attached. FIG Well Analysis The best way to predict the characteristics of a new well is to study wells of the same geologic formation in the area. The report identifies a small number of area FIG wells and identifies their yields and water quality characteristics. In summary, the identified yields are in the 400 to 700 gpm range, and water quality data suggesting relatively higher iron (0.8 - 0.9 parts per million(ppm)) and lower manganese (0.036 - 0.06 ppm) than our existing Jordan wells. As a comparison, our four Jordan wells produce (or will produce) approximately 1100 gpm and the water produced contains 0.1 to 0.5 ppm iron, and 0.3 to 0.74 ppm manganese. These two minerals cause our water to be brown and unsightly at times. The FIG wells investigated are also relatively low in the radionuclides (radium) water quality category. The estimate to drill and develop a FIG well is approximately $250,000 plus engineering, financial, and administrative costs, for a total of approximately $325,000. Mr. Qureshi recommends that a test well be drilled and tested, which will adequately predict what we could expect from a full size production well into the FIG aquifer. A test well will cost approximately $25,000 including the pump and water quality testing, plus engineering. Under a worst case scenario, the city would lose this investment, plus the cost to seal the well if the production capacity or water quality were not deemed acceptable to proceed with well development. Conclusion Staff recommends that we move forward with the test well into the FIG aquifer. The investigated area FIG wells have good water quality characteristics, but questionable to fair pumping capacities. The only way to determine what we can expect from a FIG production well is to drill the test well and analyze it. FISCAL IMP ACT: ALTERNATIVES: RECOMMENDED MOTION: REVIEWED BY: agenda considering initial report2 A FIG well adjacent to the existing Well 3 pumphouse has some advantages. The necessary piping is in place in the pumphouse for another well. A FIG well will require very little piping from the well to the pumphouse because it is another aquifer and the two wells will not affect each other. Another Jordan well would have to be over one thousand feet away so they could be operated at the same time without influencing the capacity of the existing Jordan wells. The cost for a Jordan well at another location with a stand-alone pumphouse will be approximately $500,000 to $550,000. If this Jordan well produces as expected about 1100 gpm, then its cost per gallon is $500. If a FIG well is constructed adjacent to Well No. 3 at the estimated cost of $325,000, and an estimated 500 gpm capacity, then its cost per gallon will be $650. Another advantage in drilling and developing a FIG well if it produces 500 gpm or greater and has good water quality characteristics, is that it will procure the city a certain amount of good will with the DNR. This good will may convince the DNR to allow us to drill another Jordan well in the Brookville Hills area in the future, if we manage all of our wells in a manner that least impacts the Savage Fen. If the FIG well doesn't pan out, and the DNR won't let us drill another Jordan well on the east side of the lake, then our best alternative is to drill a Jordan well on the west side of the lake. This presents us with a few issues, the main one being that we would have to re-engineer our Comprehensive Water Plan, which could cost up to $50,000. Budf(et Impact If council concurs with staff s recommendation, we will work with PCE on developing a brief specification for a test well, get at least two quotations, and return to the Council with the quotes. Then a decision can be made whether or not to move forward with the test well. Staff recommends that the funding for the test well come out of the Trunk fund. The alternatives are as follows: I. Approve a motion directing staff to prepare the plans and specifications for a FIG test well, obtain quotes, and return to the City Council to consider a contract for a test well at its earliest opportunity. 2. Table this agenda item for a specific reason. 3. Deny this agenda item for a specific reason. native number I. Mr.Qureshi of PCE will be present at any questions the City Council may have. - ~ Q - - I I ~ ~ ~ ~ I I ~ ~ ~ - - I pat ~~~'~'~:~'~~~:9~"~~': ~ 15~~2?" ~~5~:'~:;(~6~ 5!O~~. October 25, 2001 Bud Osmundson Director of Public Works City of Prior Lake 16200 Eagle Creek Ave. Prior Lake, MN 55372 RE: New Well Dear Mr. Osmundson: The City of Prior Lake needs a new well to augment its supply to meet the needs of a growing community. The City presently has three Jordan wells in a well field in the southwest part of the City. A new Jordan well has been drilled in the western part of part of town. The City is now interested in constructing a new well near the existing well field. As the DNR may not permit a new Jordan well as it may impact the Savage Fen, the City is interested in the construction of a new well in the Franconia-Ironton-Galesville (FIG) aquifer. Q ~ Progressive Consulting Engineers, Inc. was retained by the City to complete a Preliminary Well Study. This study included review of the County Well Index to identify other FIG wells in the area. PCE reviewed the specific yields and available water quality data for these wells. The study also determined the costs of constructing a new FIG well. FIG wells identified in the area were the City of Jordan Well No.5, Legends Golf Course Well in Prior Lake, Shakopee Mdewakoton Sioux Community (SMSC) Well No.6, City of Savage Well No.9, and City of Shako pee Well No. 10. Shakopee's Well No. 10 was initially drilled to the FIG aquifer, but was later drilled to the Mt. SimonlHinckley aquifer because of poor yields. The Shakopee FIG yield was only 390 gpm with 195 feet of drawdown. Some water quality data was available for all these wells, except Well No.5 in Jordan and the Legends Golf Course well. The available water quality data for FIG wells and three Prior Lake Jordan wells is shown on the attached Table 1. Water supplied to the customers should meet all EP A primary drinking water standards, including radium and nitrate. The primary standard for radium is established at 5 pCilL, and gross alpha atl5 pCi/L. Secondary standards,.unlike primary standards are not health related and are established for aesthetic reasons. Iron and manganese normally cause discoloration and the EP A has established a secondary standard of 0.30 ppm for iron and 0.05 ppm for manganese. Civil · Structural · Water Supply · Municipal . 1 Water quality data from these wells shows that a new FIG well will most likely exceed the secondary standards for iron and manganese. The radium standards may be marginally exceeded. However, blending with the three Jordan wells, which are typically low in radium, may allow the City to meet the standards. FIG Yields The capacities of the FIG aquifer wells vary considerably form 390 gpm in Shakopee Well No. 10 to 700 gpm in Jordan's Well No.5. It is important to install a test well. A test well, which is a small pilot hole, will answer questions regarding water quality and draw down and will help determine full scale well design criteria. Mr. Jerry Aljets from E.H. Renner and Sons reviewed the well data, and estimated that a 4" test well will cost about $25,000. The attached document shows the original contract price for Well No. lOin the City of Shakopee to be $337,940. This well was originally planned to be a FIG aquifer well. Another FIG aquifer well in the City of Ramsey was constructed for $98,550. In discussions with Mr. Aljets after his review of the well logs, it was determined that a new 4 FIG aquifer well will cost approximately $250,000 plus engineering and administrative expenses. The construction costs of $250,000 include well drilling, well development, a 150 hp pump, and all necessary test pumping and water quality analysis. The cost of drilling a new well is dependent upon the depth to the aquifer from the surface, which varies with location. Recommendation Considering the limited number of FIG wells in the area, we recommend that a test well / be drilled for a cost of $25,000. This will provide the water quality data, draw down, and criteria for design of the FIG aquifer well. A test well is a good investment, ensuring that a production well with construction costs of about $250,000 will work as designed. Please call me should you have any questions. Sincerely, AI a 1~~1 jrA1Lt.. Naeem Qureshi, P.E. 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