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HomeMy WebLinkAboutDrilling and Pump Testing, Fogata Lodgejehn Water Consultants, Irzc. Water Resources Consulting MEMORANDUM TO: Mr. Bobby Butler, The Wells Partnership, Inc. FROM: Chris Endler, Matt Welsh DATE: September 4, 2007 1,565 Gilpin Street Denver, Colorado 802.18 (303) 321 -8335 (303) 321 -8316 am) SUBJECT: Description of Drilling and Pump Testing, Fogata Lodge, Vail, CO JOB NO: 703.1 This memo is a description of the drilling and pump testing procedures that Jehn Water and the contractors, Living Water, Inc, and Colorado Pump, Inc., plan to conduct at the proposed Fogata Lodge site in Vail, CO. Living Water will drill a total of six boreholes. Two of these will be converted to 6 -inch diameter pumping wells and the other four will be converted into 4 -inch diameter monitoring wells. The wells will be drilled in two clusters of three wells each, one pumping well and two monitoring wells. The 2 monitoring wells will be located approximately 10 and 20 feet, respectively, from the pumping well, in different directions. The monitoring wells will allow the measurement of adjacent water levels as the 6 -inch well is being pump tested. The approximate locations of the two well clusters are shown on Figure 1. All six boreholes will be drilled using an ODEX -type drill rig, which uses air to circulate cuttings and water to the surface and temporary casing to prevent the holes from collapsing during drilling and well construction. All boreholes will be drilled to a depth of approximately 80 feet, which corresponds to approximately 20 feet below the projected excavation depth. Upon completion of drilling at each borehole, a well consisting of 60 feet of slotted PVC well screen (0.040 -inch slot openings) and 20 feet of solid PVC casing will be installed. The well screen and casing will be 6 -inch diameter in the pumping wells and 4 -inch diameter in the monitoring wells. Clean, sorted sand will be placed in the borehole around the screen, to a d epth above the top of the screened section to form a filter pack around the well. The filter pack is then sealed with bentonite to prevent infiltration of surface water into the well. Each well will then be developed by air jetting to clean silt and sand from the well, filter pack, and surrounding formation to ensure accurate water levels and clean water flowing to the pump during the pumping tests. The water discharged during drilling and well development will be contained on site in a large dumpster or similar container and removed to a treatment facility. After all the wells are installed and developed, Colorado Pump will separately conduct 2, 8 -hour pumping tests, one at each well cluster location. A 15 -25 gallon -per- minute submersible pump will be installed in the 6 -inch diameter well and run at a constant rate Mr. Bobby Butler September 4, 2007 Page 2 of discharge for 8 hours. Electronic pressure transducers will be temporarily mounted in the pumping well and both of the adjacent monitoring wells to continuously monitor water levels during the pump test and immediately after, during a well recovery period. This data will be used to determine aquifer properties for use in the ground water modeling analysis and dewatering system design. It is expected that water produced during the pump testing will be clear enough to meet all regulatory requirements to be allowed to runoff into site storm sewer grates. Appropriate tests will be conducted on the discharge water to assure that the requirements are met. It is estimated that the drilling, well installation, and well development will take approximately 6 to 8 working days and the pump testing will take 2 to 4 working days. N Sources: W +E NOTE: DRAWING NOT TO SCALE Site Plan courtesy Ground Engineering Consultants. Projection: Job No. 703.1 S UTM NAD83 Prepared By: CJE 09/04/07 Checked By: Jehn Water Consultants, Inc. Approximate Locations 1565 ,, Gilpin C Street 18 �f� of Drilling and Pump Testing Figure (303) 321-8335 (303) 321 -8346 fax'�D� Fogata Lodge Jelin Water Consultants, Inc. Water Reso urces Consulting MEMORANDUM TO: Mr. Bobby Butler, The Wells Partnership, Inc. FROM: Matt Welsh, Chris Endler DATE: September 20, 2007 1 65 Gilpin Street Denver, Colorado 80218 (303) 321 -8335 (303) 321 -8346 (�xx) SUBJECT: Questions from Leonard Sandoval, Fogata Lodge, Vail, CO JOB NO: 703.1 This memo addresses questions from Leonard Sandoval of the Town of Vail regarding the proposed discharge into the storm sewer. Mr. Sandoval asked two questions in response the memo by Jehn Water Consultants, Inc. (JWC) dated 4 September 2007: (1) how will water be discharged to the storm sewer without affecting traffic to the Enzian and Lionshead Inn properties; and (2) how will the discharged water be monitored to ensure that it is clean? Response to Question #1 Water will be discharged to the storm sewer inlets through flexible hoses. Vehicles will be able to drive over the hoses to access the Enzian and Lionshead Inn properties. Additionally, we will make all attempts to position drilling equipment and vehicles so as not to block traffic from entering these properties. Response to Question #2 Water may be discharged to the storm sewer during three project stages: (1) well development; (2) pump testing; and (3) construction dewatering. Water discharged during well development will be collected and stored in a large container until the sediment particles have settled. The clear water will be pumped to the storm sewer inlet, and the sediment in the storage container will be disposed of off -site. If the sediment does not settle within a reasonable amount of time, the water will be taken off- site and disposed of at an appropriate facility. During the pump tests, a sand content monitor will be installed on the discharge piping. If the discharged water contains significant amounts of sediment, the water will then be collected and disposed of. During construction dewatering, the discharge will be sampled as required by the Minimal Discharge Industrial Wastewater (MINDIS) permit. Although the MINDIS permit has not yet been issued by the Colorado Department of Public Health and Environment (CDPHE), JWC can predict the sampling requirements based on similar projects in the Vail area. JWC expects that the MINDIS permit will require regular sampling of total suspended solids (TSS), total dissolved solids (TDS), pH, and visual inspections for an oily sheen. The Wells Partnership, L.L.C. or JWC will ensure compliance with the MINDIS permit. Please feel free to contact us if you have any further questions.