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1e Change Order Well No. 9CITYOF CHANHASSEN 7700 Market Boulevard PO Box !47 Ohanl'assen MN 5531 ? Administration Phone; 952227'1100 Fax; 95222? 1110 Building Inspections Phar/e: 952 227 1180 Fax: 952 2271190 [ngineering Phone: 9522271160 Fax: 952 2271170 Finance Phone: 952227 11,$0 Fax: 9522271110 MEMORANDUM TO: FROM: DATE: SUB J: Todd Gerhardt, City Manager Patti Oehme, City Engineer/Dir. of Public Works August 3, 2004 Consider Change Order No. 1 for Well No. 9 Improvements Project No. 03-02 REQUESTED ACTION Approve Change Order No. I for Well No. 9 Improvements in the amount of $27,542.50. BACKGROUND Park & Recreation Phone: 9522271120 Fax: 9522271110 Recrea'do[ Center 2310 Coulter Boulevard Phone; 952 2271400 Fax 9522271404 The City Council approved plans and specifications for Well No. 9 on March 22, 2004. The City Council authorized the well drilling contract on May 10, 2004. DISCUSSION Planning & Natural Resources Phone 952 2271130 Fax: 952 227 1110 Public Works 1591 Park Road Phone: 9522271300 Fax: 952227 1310 The Well No. 9 contractor has encountered a changed condition in the geologic formations at the well site. The original design called for establishing an 18-inch diameter casing through the Prairie du Chien formation with an 18-inch diameter open hole below this formation into the Jordan formation. This open hole in the Jordan formation would allow water from the formation to be pumped to the City's water system. Senior Cenler Phone: 952.2271125 Fax: 952227 1110 Web Site '~c~vw ci chanhassen fnrl Js The well driller has encountered a significantly fractured Prairie du Chien formation. This formation does not appear to be able to structurally support the 18-inch casing as originally designed. The test well performed prior to the drilling the well was unable to confirm the integrity of the Prairie du Chien formation due to the size and scope of test wells. In order to establish the casing in the hole and maintain the integrity of the rock and gravel formation around the well, a screened-type well design will need to be utilized with a gravel pack around the screen. This screen would extend through the Jordan aquifer. This type of well design will not affect the potential capacity of the well, and is similar to the well design cun'ently in place at Well Nos. 5 and 6. The change order is in the amount of $27,542.50. The City's consultant for Well No. 9 has reviewed the scope of the change order and amount and finds it The City ct Chanhassen * A growing comrrunit? with clean lakes quality $£hools Todd Gerhardt August 3, 2004 Page 2 acceptable. The amount is consistent with screened well bids on other well construction projects. Staff recommends Council approve Change Order No. 1 for Well No. 9 Improvements in the amount of $27,542.50. Attachments G:\F, NG\I~UBLIC\03 02\bg C}lmlge ~drr #1 080904.dt~c SECTION 00991 - CIIANGE ORDER (Instructions on reverse side) No. 1 PROJECT: Well No. 9- Construction DATE OF ISSUANCE: July 29, 2004 EFFECTIVE DATE: July 29, 2004 OWNER: City of Chanhassen OWNER's Contract: Well No. 9 - Construction CONTRACTOR: Mark J. Traut Wells ENGINEER: Bolton & Menk, Inc. You are directed to make the fi)llowing changes in the Contract Documents. Description: Modify well design to utilize a well screen type design. See attached table for modifications to Schedule of Unit Prices.. Reason for Change Order: PraMe-Du-Chien Formation is structurally unable to support 18" casing as originally designed. Screen type design with gravel pack will provide appropriate support. Attachments: (List documents supporting change) Revised Figure A-4. CHANGE IN CONTRACT PRICE: Original Contract Pricc $521.330.00 Net changcs from previous Change Ol'dcrs No.__to No.__ $ 0.0 Contract Price Prior to this Change Order $521.330.00 Net Increase (lncreasc/Dee:'ease) of this Change Order $27,542.50 Contract Price with all approved Change Orders $548~872.50 CHANGE IN CONTRACT TIMES: Original Contract Times Substantial Completion :__days or dates P, cad7 for final paement :~150 days or datcs Net changes from previous Change Orders No.__to No.__ 0 days (?ontract Titncs prior to this Change Order Substantial Completion : days or dates Ready for final pa?~cnt :~150 days or dates Nct Increase (lucrease/Dec:-ease) of this Change Ordcr 0~days Contract Times with all approved Change Orders Substantial Completion :_ days or dates No,,'. 25. 2003 Ready for final payment : 150 ditys or dates Nov.. 25, 2003 P, ECOM MENDEI): AI)PP, OVED: AC(?EPTED: By: Date: Engineer (Authorized Signature) By:. By: Owner (Authorized Signature) Date: Date: Contractor (AuOiorizcd Signature) EJCDC No. 1910C8-B (1990 Edition) Prepared by the Engineers Joint Contract Documents Committee and cndorscd by The Associated General Contractors of America. CHANGE ORDER PAGE 00991-1 CHANHASSEN, MINNESOTA PROPOSED WELL NO. 9 WELL PROFILE +3 Ground El. Surficial Deposits (Clay/Rocks/Sand) 30" Steel Casing Grout 180' 180' 24" Steel Casing 365' Prairie du Chien Formation (Boulders/Limestone) 373' Grout 365' 18" Steel Casing 373' Gravel Pack Jordan Formation (Sandstone) 498' Proposed 12" SS Screen FIGURE A-4 (Rev. 7/29/04)