Loading...
Exh 9A2301 Maitland Center Parkway, Suite 300 Maitland, Florida 32751 tel: 407660-2552 ' fax: 407875-1161 May 2, 2002 Ms. Donna Kaluzniak, C.E.P. Utility Director .City of Atlantic Beach 1200 Sandpiper Lane Atlantic Beach, FL 32233-4318 Subject: Assessment and Maintenance of Atlantic Beach Floridan Aquifer Production Wells, City of Atlantic Beach, Florida Dear Ms. Kaluzniak: AGENDA ITEM #9A MAY 28, 2002 On December 3, 2001, January 21, and March 18, 2002, Camp Dresser and McKee Inc. (CDM) provided resident oversight of contractors involved in removing the pumps, with associated suction pipe and /or manifolds, from four Floridan aquifer production wells located at the Atlantic Beach Water Treatment Plants No. l and No. 2. The pumps were inspected for buildup of minerals (caldfication), general maintenance, repair, and evaluation Following the removal of the pumps, with associated suction pipe and/or manifolds from the wells, the wells were logged with video and geophysics to evaluate their condition This letter report snmmari~va the observations and evaluations of the assessment of the Atlantic Beach Service Area production wells. In addition, this letter report includes CDM's recommendations for present and future well use. Background Water Treatment Plant (WTP) No. l (46911 street) receives an average of approximately 1,650 gpm of water from production wells 1 and 2 when in use. Production well l is located at the plant, while well 2 is located neazby at the Water Pollution Control Facility (1100 Sandpiper Lane). Production well 1 was installed in 1953 and is a free flowing artesian well with a vertical turbine pump. Production well 2 was installed in 1962 and is an artesian well, which free flows through a pipe system to a storage tank klcated at WTP No. 1. Well 2 is capped and its flow to WTP No. l is controlled with a gate valve. Production wells 3 and 4, located at WTP No. 2 (2301 Mayport Rd.), are free flowing artesian wells. Well 3 has a Jacuzzi pump in an adjacent pump house, and well 4 has a vertical turbine pump. Production well 3 was installed in 1976, while well 4 was installed in 1998. Table 1 is a summary of the water supply production wells in the Atlantic Beach Service Area and their assocated pumping capacities. Since the time of their installation, the City of Atlantic Beach (COAB) has experienced significant losses in well yields from three of the four production wells. The well assessment was needed to consulting•engineering •constructlon •ooerat ons AGENDA ITEM #9A MAY 28, 2002 Ms, Donna ICaluzniak, C.E.P. May 2, 2002 Page 2 determine the possible causes of the losses in well yield, to perform maintenance as necessazy on the well pumps, to provide well data in support for a Consumptive Use Pemrit renewal, and to make recommendations for improving production capadty to meet current and future potable water demands. W. Eazl Floyd & Sons,. Inc. provided well repair services. Advance Borehole Services performed the geophysical logging, and Deep Venture performed the video logging. A professional geologist from CDM provided oversight during logging and repairs to wells and helped with interpretation of the logging.. In addition, at the request of the St Johns River Water Management District (SJRWMD) and the COAB, CDM reviewed video and geophysical logs for wells 2 and 4 with Mr. Rick Spechler of the United States Geological Survey (USGS). Mr. Spechler was involved in the geophysical logging of select COAB wells in the eazly 1991Ys, as part of a regional USGS study of the Floridan aquifer. Field Observations In addition to the color video log, the following geophysical logs were used in the evaluation of the wells: caliper (determines borehole size), gamma (used. for interpreting lithology), resistivity (used primarily to identify possible salt water intrusion), specific conductance (a measurement of the ionic content, which is an induator of salt water intrusion), temperature (helps identify water source), and flow velodty (aids in identifying most-productive water bearing zones). Table 2 s~+**»*+~ri~eS the significant video and geophysical observations of all four wells including well construction details. WTP No. l Well l Well 1 is located in the southwestcomer of the properly at WTP No. 1. Well 1 has a 12-iruh casing terminating in the limestone (410 ft) followed by an open borehole in the Floridan aquifer extending down to a total depth (TD) of 1,002 feet The well is a hee flowing artesian well. It has a vertical turbine pump with ti0 ft of suction pipe. The well is 47 yeazs old. Video logging revealed that this well has excessive mineral (CaCOj) scaling (numerous scale protrusions off the casing - see attached videos) throughout the casing, with the heaviest buildup scaling occurringfrom285- 410 feek Geophysical logs of temperature and resistivity aze indicative of cooler fresh water flowing into the well and correlates with the zones from cavities and porous limestone observed on the video and caliper logs. Flow velodty logs show a reduced flow below 925 feet to TD. Overall, resistivity was high and specific conductance was low throughout the open-hole section of the well indicating fresh groundwater recharging the well Well2 Well 2 has an 18-inch casing extending to % feet which then reduces to a 12-inch. casing extending to 407 feet The well has an open borehole in the Floridan aquifer extending down to a TD of 1,290 AGENDA ITEM #9A MAY 28, 2002 •~ Ms, Donna ICaluzniak, C.E.P. May 2, 2002 Page 3 feet. The well is located at the entrance of the Water Pollution Control Fadlity and is piped to WTP No. 1. The well is artesian and free flows to WTP 1 without the use of a pump. The well is 40 years old. Video logging revealed that this well has even more mineral (CaC03) scaling and pitting throughout the casing than welll. Geophysical logs of resistivity and specific conductance indicate that the well has signs of saltwater intnuion The water quality is twice as conductive as well 1. There is a zone from 1,168-1,180 feet with a high flow velocity and poorer quality wafter. Limited water quality sampling of the well in 2001 by the Gty further substantiates evidence of saltwater intrusion The SJRWMD considers fresh groundwater in northeast Florida, unaffected by saltwater intrusion, bo have diloride concentrations in the range of 20 to 30 mg/1. Well 2 was sampled twice in 2001 and had reported concentrations of 98 mg/1 Quly 25~) and 113 mg/1 (November 5~). WTP No. 2 We113 Well 3 is located on the southeasYcomer of WTP No. 2. This well is a free flowing artesian well with a centrifugal Jacuzzi pump in an adjacent pump house. The well has a 16-inch surface casing (110 ft) that reduces to 12-inches terminating in the top of the limestone (394 ft) and is followed by an open borehole in the Floridan aquifer extending to 1,014 feet. Well 3 was installed in 1976 and is 25 yeazs old Video logging revealed that this well is in fair condition There is moderate build up of scaling. Groundwater clarity was exceptional with little suspended particles flowing through the well. Numerous cavities and fractures were observed to have significant flow velocities, decreases in temperature, and anomalous resistivity highs. This data is indicative of fresh water flowing into the well at these areas in the limestone. Most of the flow appears to be coming from above 900 feet. There is a zone with vertical fractures and voids, which is apparently a contact between different lithology and formations. This fracture zone can be seen in all 4 production wells. The zone can be seen at slightly deeper depths in wells 1(671-674 ft), 2 (678~i79 ft) and 4 (663-667 ft). This zone appears to be a prolific water-bearing zone in each of the wells. We114 Well 4 is located on the west side of WTP No. 2 The well was installed in 1998. It has a vertical turbine pump with 65 feet of suction pipe. The well has a 16-iruh surface casing (100 ft), redudng to 12-inches terminating in the bop of the limestone (422 ft), with an open borehole in the Floridan aquifer extending to 684 feet. The well was observed to be in good condition (no scale protrusions off the casing -see attached video). There was very little build-up of scaling inside the casings. An offset of approximately 4 inches was observed in the open borehole beginning at 493 feet, indicating that the well is not completely plumb. AGENDA ITEM #9A MAY 28, 2002 Ms, Donna ICaluzniak, C.E.P. May 2, 2002 Page 4 The gamma and resistivity logs showed a similar profile to well 3. -The flow velocity log was relatively consistent with a slight inaease at approximately 455 feet There were almost no gamma counts recorded from 426570 feet indicating an exceptionally clean and pure limestone void of clay, organics, or phosphate. Assessment of Reduced Production Based on the video and geophysical logging and field observations performed for this project, there are several maintenance activities and improvements that need to be made to increase the reliability of meeting current and future water demands. The age of wells 1, 2, and 3, combined with regional drawdown in the potentiometric surface elevation of the Floridan aquifer, have resulted in reduced yield from the Atlantic Beach Service Area water supply wells. Data from a USGS monitoring well installed neaz Mayport indicates a reduction in potentiometric surface elevations in the area over the last 5 years. This is substantiated by groundwater modeling performed by the SJRWMD (Durden,1997 and 2000) showing that pumping from other legal users of water QEA, the NAS, and Jacksonville Beach) has caused a reduction in the potantiometric surface of the aquifer.. Additionally, well losses due to calcification of the well have further decreased the specific capacity (discharge per unit foot of drawdown) of the three older wells. Well Repair CDM subcontracted W. Eazl Floyd & Sons, Inc. to remove manifolds, pumps, and assodated suction pipe. During the removal of $re pump and suction pipe for well 4 at WTP No. 2, it was observed that the drive shaft was made of carbon steel with a small section of stainless steel. The sections of thecarbon-based drive shafts were damaged. These were replaced with 65 feet of new stainless steel shafts. Tn addition, Fioyd & Sons replaced adamaged 5-foot section of suction pipe. Table 3 is a summary of the well repairs. Recommendations A summary of existing water supply well conditions and recommendations for future water supply are presented in Table 4. This assessment was conducted to refine the recommendations in the Water Master Plan for water supply well rehabilitation replacement As indicated in the table, CDM recommends that the COAB abandon well 2 at the WTP No.1. This well cannot be rehabilitated, due to excessive corrosion of the well casings and the age of the well. In addition, there is evidence of saltwater intrusion occurring at greater depth (lower Floridan aquifer) in this well. Therefore, as required by the SJRWMD (Chapter 40C~, FAC -Water Wells), the well should be abandoned due to potential cross contamination of aquifers. The COAB can take advantage of the St Johns River Water Management District ccet sharing well abandonment program which will pay for up to 25 percent of the cost of well abandonment Well AGENDA ITEM #9A MAY 28, 2002 Ms, Donna Kaluzniak, C.E.P. May 2, 2002 Page 5 2 should be replaced with a new shallower well (700 to 800 feet bls) capable of providing a similar yield to the existing well. Abandonment and replacement of this well is consistent with recommandations in the Water Master Plan Well 1, located at WTP No.1, should be decommissioned and replaced within 5-7 years due to caldflcation and corrosion of the well casing. Well 3, at WTP No. 2, should also be decommissioned and replaced within 7-10 years due to calcification and mnosion of the well casing. Abandonment and replacement of these wells is consistent with recommendations in the Water Master Plan Based on the condition assessment of the Atlantic Beach water supply wells, CDM suggests that the Water Master Plan's recommendation to interconnect the Atlantic Beach and Buccaneer water systems be completed as soon as possible. The interconnection provides the city with an appropriate level of supply redundancy and flexibility. CDM recommends the replacement of well 2 be added to the cit}/s capital improvement program as a project requiring immediate funding. All new wells should be logged every 10 yeazs to observe the integrity of the well casings and pumping capacity. If you or your staff have any questions concerning the contents of this letter report, please call me at (407) 660-2552. Very truly yours, ~N - V V v/~^^-'~ lpe P. Wiseman, P.E. Principal Engineer Camp Dresser & McKee Ina LPW/sb FILE: 20376-34518/ E-110 w/o attachments, E-600 w/attachments N:\20676\34518\AB_Welt_Letter.doc c: Jim Hanson -City of Atlantic Beach (w/o videos) Donald Maurer, P.E. - CDMjJacksonville (w/o videos) Jason M. Mills, P.G. - CDM/Orlando (w/o videos) Tahle 7 Inventory of Existing Water Supply Wells and Pumping Capacity Data for the Atlantic Beach Watsr System Weil or Welifield Casing Casing Total Well veld Actual Existng or Pum p or Faali ry Dia. D th ~ pa yt p at Time of Pump Date Pum Ped or Flowing proposed In Use? Source Type Number Name M) (ft) (fr) Installation Ca act o b Drilled (date) (Y or N) Aquifer in m i 1 AB WTPt 12 470 1,002 2,000 950 1953 Vertical lurbine 75 h Existing Y Foridan Hous 2 AB WTPt 18 x 12 18' - 96 tr-ao7 1,290 •3000 •700. 1982 Free Fbwing ExisBrg Y Floridan Hous 3 AB W1P2 18 x 12 15' - t 10 1r - 394 1,014 2,500 1,650 1978 JagrIIi 30 hp Existlrg Y Foridan Hous 4 AB WIP2 16 x 12 18• - 100 tr-4zz 884 .1,850 1,750 1998 .Vertical turbine 30 hp Existing Y Foridan Household use • Artesian well free flowing wHlwtd a pump on it. AB =Atlantic Beach Alfa - n.120378134578\Tal>Im.xls \ TaUb7 Pape 1 of 7 a n ~z Ke - N 4~i OD y O ~ O N ~ - 5/2/02 ~ of Use' ehoW use elxtld use etx9d use