SAP Addendum Specific to Delivery Order TO 0008

Section 2- Groundwater Well Sampling

Under this task order, a total of three rounds of quarterly groundwater sampling will occur between September 2003 and June 2004. Thirty-nine on-post wells will be sampled (either drinking water, monitoring or agricultural/livestock wells). Additionally, up to 40 off-post private and public drinking water wells will be sampled quarterly between September 2003 and June 2004. Table 1 indicates the number of wells and sampling parameters that will be funded under this contract. A breakdown of quarterly sampling events by well and analyte is provided in Appendix A.

Sampling of the wells will be based on AFCEE Handbook procedures with exceptions as appropriate for the hydrogeology at the site. The wells will be purged in accordance with low-flow sampling techniques. QA/QC sampling and analysis will be performed to meet requirements in the CSSA QAPP. Purged water will be containerized and transported to the GAC treatment system (set up under RL74) prior to discharge at CSSA�s Outfall 002.

2.1 - Water Level Measurements

Water level measurements will be obtained from on-post monitoring, agricultural and drinking water wells that provide good access for an electric measuring device. The depth to water will be measured to the nearest 0.01-foot with respect to the surveyed reference point on the top of the casing. If no clear reference point exists, the reading will be obtained from the north side of the well casing as a reference point. Drinking water wells are equipped with gauging tubes for obtaining water levels.

In the past, drinking water supply wells were shut down before a quarterly event (no more than 48 hours) to allow the aquifer to equilibrate. Due to the addition of wells installed in specified zones the drinking water supply wells are no longer needed to produce the potentiometric maps, therefore shutting down these wells is no longer necessary. A water level measurement will still be collected during quarterly water level measurements. The recently installed solar powered pump at CS-I will required shut-off prior to collecting a water level measurement.

A total of 14 transducers have been installed in on-post wells, and two weather stations have been set-up. The weather stations are located near CS-MW16-LGR along the northern fenceline of the inner cantonment, and near the southeast corner of the inner cantonment, west of Building 90. The transducer locations are CS-MW9-LGR, CS-MW9-BS, CS-MW16-LGR, CS‑MW16-CC, CS-MW4-LGR, CS-MW11A-LGR, CS-MW11B-LGR, CS-MW19-LGR, CS-1, CS-10, CS-11, CS-MW1-CC, CS-MW2-CC, and CS-MW12-CC. Eight additional transducers are scheduled for future installation in on-post wells. Data from all well transducers and weather stations will be downloaded as part of each quarterly event.

2.2.1   On-post Wells with Dedicated Low-Flow Bladder Pumps

A goal of the CSSA groundwater monitoring program is collection of data that is most representative of conditions at the site. It is generally accepted that static water in the well casing is not representative of the formation water and needs to be purged prior to collection of groundwater samples. However, water in the screened interval may indeed be representative of the formation, depending on well construction and site hydrogeology. CSSA uses a low-flow sampling strategy in many of the on-post monitoring wells. The use of low-flow purging and sampling techniques mitigates sampling-induced turbidity problems. The following discussion and procedures are excerpted from the USEPA guidance entitled Low-Flow (Minimal Drawdown) Ground-Water Sampling Procedures (USEPA, 1995).

Low-flow refers to the velocity with which water enters the pump intake and is imparted to the formation pore water in the immediate vicinity of the well screen. The objective is to pump in a manner that minimizes stress (drawdown) to the system to the extent practical, taking into account established site sampling objectives. Typically flow rates on the order of 0.1-0.5 liters per minute (L/min) are used; however, some extremely porous formations can be successfully sampled at flow rates to one (1) L/min. Isolation of the screened interval water from the overlying stagnant casing water may be accomplished using low-flow minimal drawdown techniques. When the pump intake is located within the screened interval most of the water pumped will be drawn in directly from the formation with little mixing of casing water or disturbance to the sampling zone.

CSSA utilizes a QED Well WizardTM system for collecting low-flow samples. The sampling device consists of a pressurized nitrogen gas canister, pneumatic controller, gas injection tubing, a bladder pump, a drop pipe with inlet (deeper wells only), and discharge tubing. Prior knowledge of the well construction is necessary to assist in purging. At a minimum, any stagnant water remaining in the pump tubing needs to be purged so that formation-representative groundwater is being collected at the sampling port. A minimum purge volume is defined as the amount of water held in storage within the 3/8-inch discharge tubing. Water may stagnate within the discharge tubing between sampling events since it is held by a check valve located at the pump. Table 2 lists the current and anticipated low-flow pump systems to be sampled at CSSA. An estimated minimum purge volume to evacuate stagnant water is also included in this table. As additional wells are completed and actual construction information becomes available, the table will be updated.

Well purging is necessary to obtain samples of water from a formation in the screened interval. Rather than using the arbitrary guideline of purging three casing volumes prior to sampling, water quality measurements will be used to establish stabilization time for several parameters (e.g., temperature, pH, specific conductance, and turbidity) on a well-specific basis. Data on pumping rate, drawdown, and volume required for parameter stabilization can be used as a guide for conducting subsequent sampling activities. The following recommendations should be considered:

Prior to sampling, all sampling devices and monitoring equipment will be calibrated in accordance with manufacturer�s recommendations and the SAP (Volume 1-4: Sampling and Analysis Plan). Calibration of the pH meter should be performed with at least two know pH solutions that bracket the expected range.

During sampling events conducted after significant rain events or when the water table is elevated more than 100 feet above pumps, extra care shall be taken to slowly increase nitrogen pressure in the low-flow sampling system. These procedures are intended to decrease stress on the pump systems and reduce the possibility of damaging pump bladders.

Table 2 - Low-Flow Pump Installation Data and Minimum Tubing Purge Volumes

The USEPA recommends that the water level be checked periodically to monitor drawdown in the well as a guide to flow rate adjustment. The goal is minimal drawdown (<0.1 meter) during purging. At CSSA, it is unlikely that the dedicated bladder pumps can create such a drawdown in the main karstic aquifers (e.g., LGR and CC). In lower yielding intervals (perched aquifer or BS wells) this goal may be difficult to achieve under some circumstances due to geologic heterogeneity within the screened interval, and may require adjustment based on site-specific conditions and experience of the Parsons field team.

Water quality indicator parameters will be continuously monitored during purging. The water quality indicator parameters monitored can include temperature, pH, conductivity, and turbidity. The last two parameters are often most sensitive. Pumping rate, drawdown, and the time or volume required to obtain stabilization of parameter readings can be used as a future guide to purge the well. Measurements should be taken every 3‑5 minutes. Stabilization is achieved after all parameters have stabilized for three successive readings at some volume beyond the minimum purge requirements. Three successive readings should be within � 1◦ F (� 0.5◦ C) for temperature, � 0.1 for pH, � 5% for conductivity, and � 10% for turbidity.

Samples will be collected upon stabilization of water quality parameters. If an in-line device is used to monitor water quality parameters, it should be disconnected or bypassed during sample collection. Sampling flow rate may remain at established purge rate or may be adjusted slightly to minimize aeration, bubble formation, turbulent filling of sample bottles, or loss of volatiles due to extended residence time in tubing. Typically, flow rates less than 0.5 L/min are appropriate. The flow rate for volatile sampling should approach 0.1 L/min. Generally, volatile (e.g., solvents and fuel constituents) and gas sensitive (e.g., Fe 2+, CH4, H2S/HS-, and/or alkalinity) parameters should be sampled first. If filtered (dissolved) samples are needed, filtering will be performed last, and in-line filters should be used. Groundwater samples should be collected directly into this container from the pump tubing.

2.2.2   Shallow Wells Sampled by the Bailer Method

On occasion, shallow perched aquifer wells not equipped with any pumping apparatus will require sampling. Currently, this group of wells includes the AOC-65 piezometer wells, CS-MW1, CS-MW2A, CS-MW2B, CS-MW3, and CS-MW4. Two of these wells are routinely dry; therefore, sampling of these wells will be conducted following precipitation events rather than on a quarterly schedule. At CSSA, these types of wells usually do not freely yield water, and are usually purged to dryness before attaining any minimum purging requirement. Samples are collected after a sufficient volume of groundwater has accumulated within the wellbore to obtain an adequate sample volume.

Before each monitoring well is purged and sampled, the water level will be measured within �0.01 foot with respect to the reference point on the top of the casing. Using the static water level, well casing diameter, and total depth of the well, one well casing volume is calculated and recorded. Purging of low-yielding observation points is performed by removing up to three well casing volumes from each monitoring well, or until the well has gone dry. The water is removed via a decontaminated or disposable Teflon bailer and placed in a drum or other leakproof container. The field sampling team may find that a disposable bailer is not adequate for purging because of its lack of rigidity, thus a decontaminated rigid bailer may be used. Purging and sampling will be performed in a manner that minimizes agitation of sediments in the well and formation. Equipment will not be allowed to free-fall into the well, and the bailer will be lowered into the water column slowly. All purged groundwater produced from these wells will be treated at the CSSA GAC unit.

Groundwater samples will be collected in the order of increasing anticipated contamination when possible. Careful use of the bailer will minimize sample agitation and contact with air. A clean length of nylon cord will be used for raising and lowering the bailer in each well. The bailer rope should not be allowed to touch the ground during sampling. For every 0.5 well volumes removed, measurements of pH, temperature, and specific conductivity are collected and recorded in the logbook. Because of the nature of these wells, turbidity will not be a stabilization criterion. Ideally, when at least three subsequent measurements are within 10 percent of each other, it is indicative that water is being removed from the aquifer rather than from the well casing. However, if the well goes dry before three well volumes, this standard may not be achievable. When a low-yield monitoring well is bailed dry before three well volumes are removed, the sample will be collected as soon as the volume of recovered fluid is sufficient for sampling.

Westbay^�-equipped monitoring wells will be monitored and sampled monthly from August 2003 until September 2004. Samples from these wells will be obtained on a monthly frequency plus immediately after a qualifying precipitation event. In general, CSSA will be responsible for collection of data from the Westbay^� wells. Parsons will supply one field technician per groundwater sampling event. Groundwater samples will be collected from discrete intervals using the Westbay^� device for a period of six months. Sampling frequency will utilize the following scheduling parameters:

Note: The samples will be collected within 72 hours of the rain event. This allows for samples to be collected on Monday should the rain event occur on Friday. After each sampling event the data will be evaluated to determine if monthly or other sampling is necessary.

The sampling and use of the multi-port monitoring devices require specialized training provided by Westbay^�. Several people from CSSA and Parsons were trained on the correct usage and procedures for obtaining meaningful data. Requirements for measurement, purging, and sampling were provided by Westbay^� at that time.

2.2.4   Deep Wells Sampled by the Bailer Method

Quarterly groundwater events include deeper, larger diameter wells that may be routinely sampled but are not equipped with any sampling device. Currently, there are no wells scoped for this design under TO 0008, but the need may eventually arise periodically (e.g., CS-3 and CS-4 are not equipped with pumps). Their diameter and depth preclude bailing as a feasible purging alternative. Samples collected from such wells will be obtained by bailer grab samples. The same field methodology for shallow wells will be implemented for collecting deeper samples utilizing a bailer. A single measurement for pH, temperature, and conductivity will be recorded to document the water quality. Sampling of CS-3 and CS-4 may require this sampling method.

Drinking water wells available for groundwater monitoring are purged to remove water from the pump column. Currently, these include CS-1, CS-9, CS-10, and CS-11. Purged groundwater is typically pumped into the distribution system at CS-1, CS-9, and CS‑10. CS-11 is currently off-line, therefore the well is purged directly onto the ground surface. Wells with pumps are purged 10 to 15 minutes prior to sampling. Temperature, pH, turbidity, and conductivity will be taken prior to and during purging. Well purging will be performed until temperature, pH, turbidity, and conductivity values stabilize. Stabilization is defined for pH as � 0.1 unit, temperature � 1�F (�0.5�C), turbidity as � 10 percent, and conductivity as � 5 percent. Successive measurements will be taken at 5‑minute intervals. All water quality parameters recorded while purging will be noted in the field logbook. Samples are collected from the water faucet tap located at or near the top of the wellhead.

2.2.6   Off-post Domestic and Public Supply Wells

Under TO 0008, off-post groundwater samples will be collected from select off-post public drinking water and domestic drinking water wells. Nearly all these wells are equipped with a submersible water pump, a bladder-type pressure chamber or booster pump, and possibly a large storage capacity cistern. These wells are purged and sampled with the same criteria as the on-post drinking water wells. Most off-post well locations require a signed access agreement and a minimum of 72-hours notification to the well owner before accessing the site.

Most wells with pressure tanks can be operated by opening a faucet to create a pressure drop, thereby engaging the well pump. Cisterns and booster pumps often operate the well pump with some type of level switch (float or pressure), and therefore may require some manipulation to engage the pump. This can be accomplished either by draining water from the cistern to activate the switch, or manually engaging the switch at its location if the well is so equipped. The field sampling team will bring an extra garden hose to directly purge water to an unobtrusive location, if necessary. When possible, public drinking water supply wells will be operated by the owners of the system or their designated representative only. The City of Fair Oaks has instructed Parsons� personnel in proper procedures for sampling FO-J1, as set out below.

The field sampling team must ensure that the pump is running when the groundwater sample is collected. CSSA has already retrofitted several off-post domestic wells with wellhead sampling ports. All samples must originate at or as near to the wellhead as possible prior to other system influences, which include pressure tanks, booster pumps, water softeners, and/or cisterns.

Because of the variability in privately owned drinking water systems, multiple procedures are required to assure that the well pump is running and that a representative groundwater sample is obtained. Instructions for the individual off-post wells sampled to date are included to ensure sample integrity and proper entrance and exit from the well owner�s property without disrupting the well owner. Future off-post drinking water wells added to the monitoring program should follow similar procedures, as applicable.

2.2.6.1   FO-J1 (Owned and operated by Fair Oaks Ranch Utilities, City of Fair Oaks)

1. The well is located behind JW-14�s residence. Enter through the gate at south end of property. The key is kept in the CSSA key box. Go through three gates, closing each gate behind you so the dog does not escape. The well is located in a fenced in area, see photo Appendix B, Figure FO-J1.

2. On the telephone pole next to the well make sure the power is on and pump switch is set to �Hand�, then push the start button. Note: Make sure all settings are put back as they were when you arrived, after sample is collected.

3. Purge at wellhead tap. Record pH, temperature, and conductivity readings until parameters stabilize, record approximate gallons purged.

4. Collect sample and return all setting back to original configuration as when the operator arrived, then hit the start button again.

5. Close and lock all gates.

6. For changes to this accepted procedure or any other questions regarding the Fair Oaks Ranch Utilities public drinking water wells, contact Mr. John B. Moring, Jr., Fair Oaks Ranch Utilities, 7286 Dietz Elkhorn Rd, Fair Oaks Ranch, TX 78015, (210) 652-7929.

2.2.6.2   HS-2

1. Note: First contact Bexar Metropolitan Water District to schedule the Leon Springs (LS-1, LS-2, LS-3 and LS-4) and Hidden Springs (HS-2 and HS-3) sampling. Contact Mr. Roger Placencia, Bexar Metropolitan Water District, 2047 W. Malone, San Antonio, TX 78225, (210) 357-5707.

2. Bexar Metropolitan employees will unlock gate to provide access to well area for sampling and engage the well pump.

3. The well is located in a gated area, see site map, wells are numbered on wellhead.

4. Purge at wellhead tap, see Appendix B, Figure HS-2. Take pH, temperature, and conductivity readings until parameters stabilize, record approximate gallons purged.

5. Collect sample from wellhead tap.

2.2.6.3   HS-3

1. Bexar Metropolitan employees will unlock gate to provide access to well area for sampling and engage the well pump.

2. Well is located in gated area, see site map, wells are numbered on wellhead.

3. Purge at wellhead tap see Appendix B, Figure HS-3. Take pH, temperature, and conductivity readings until parameters stabilize, record approximate gallons purged.

4. Collect sample from wellhead tap.

2.2.6.4   I10-2

1. Contact Steve in the AAA Stowaway offices (in shopping center near Diamond Shamrock). Steve will escort you to the well located in the storage unit area and unlock necessary gates and doors.

2. Watch out for wasps when entering well housing.

3. A water hose is needed for purging the well to avoid flooding the well house.

4. Connect water hose and turn on water at faucet not located at wellhead to purge pressure tank and engage well pump, see Appendix B, Figure I10-2.

5. Once pump engages, listen for it to remain on, record pH, temperature, and conductivity readings from wellhead tap until parameters stabilize, record approximate gallons purged.

6. Collect sample from faucet on wellhead, leave other faucet running to avoid pump disengaging during sample collection.

7. Remove water hose and leave everything as it was upon arrival.

2.2.6.5   I10-4

1. Well is located to the left of house.

2. Climb up the cistern and depress float switch to engage pump, see Appendix B, Figure I10-4.2.

3. Purge at wellhead, see Appendix B, Figure I10-4.1. Record pH, temperature, and conductivity readings until parameters stabilize, record approximate gallons purged.

4. Collect sample from wellhead tap.

5. If needed, climb cistern and be sure float switch is in the original position as it was upon arrival.

2.2.6.6   I10-7

1. Well is located at back of property, follow driveway back and well is to the left, in a building resembling an outhouse, see Appendix B, Figure I10-7.

2. Turn on water at house faucet to right of driveway to purge pressure tank which will engage the well pump.

3. Purge at wellhead. Record pH, temperature, and conductivity readings until parameters stabilize, record approximate gallons purged.

4. Collect sample from wellhead tap.

5. Make sure water is turned off at the faucet to right of the driveway before leaving.

2.2.6.7   JW-6

1. Must have gate code to enter (contact well owner for current code).

2. Well is located straight ahead when entering the driveway, behind trees.

3. Turn on water faucet at pressure tank to engage well pump, see Appendix B, Figure JW-6.

4. Purge at wellhead. Record pH, temperature, and conductivity readings until parameters stabilize, record approximate gallons purged.

5. Collect sample from wellhead tap.

6. Turn off all water faucets.

2.2.6.8   JW-8

1. Well is located at end of driveway, look for the cistern (Appendix B, Figure JW-8.1).

2. Watch out for bees and scorpions at wellhead.

3. Open well house and find electrical box, remove cover and hold down switch as shown in photo (Appendix B, Figure JW-8.2), this will engage the well pump.

4. Purge at wellhead. Record pH, temperature, and conductivity readings until parameters stabilize, record approximate gallons purged.

5. Collect sample from wellhead tap.

6. Return electrical box and switch to the condition they were in upon arrival.

2.2.6.9   JW-9

1. Arrive at gate, reach through and push black button on gray box to open gate, stand guard to make sure dog does not escape, close gate behind you during sampling.

2. Well is located on the right hand side of driveway, before you reach the residence. (Appendix B, Figure JW-9.1)

3. Climb on cistern and depress float switch to engage well pump, see Appendix B, Figure JW-9.2.

4. Purge at wellhead. Record pH, temperature, and conductivity readings until parameters stabilize, record approximate gallons purged.

5. Collect sample from wellhead tap.

6. Make sure all water is turned off and cistern float switch is clear of any obstructions before leaving.

7. When leaving stand guard at gate while it closes to make sure dog does not escape.

2.2.6.10   JW-13

1. Well is located to the left of the driveway across from house. (Appendix B, Figure JW-13)

2. Turn on faucet at pressure tank to purge well and engage well pump. Follow the water hose away from well and unhook the first connection encountered. This hose leads to the dog�s water and will flood the dog pen if not disconnected.

3. Purge at wellhead. Record pH, temperature, and conductivity readings until parameters stabilize, record approximate gallons purged.

4. Collect sample from wellhead tap; make sure well pump has not turned off when collecting readings and sample.

5. Turn all water faucets off, reconnect hose to dog pen, close gate behind you when leaving.

2.2.6.11   JW-14

1. Well is located to the right of house when facing it, in small stucco building by the garage. (Appendix B, Figure JW-14)

2. Turn on water faucet in front of house in flowerbed to purge pressure tank.

3. Hook up water hose to faucet at wellhead and divert water out of well house while purging. Record parameters (pH, Temperature, Conductivity, gallons purged).

4. Listen for well pump to engage.

5. When parameters stabilize, remove hose from wellhead faucet and collect sample directly from wellhead tap. Use a collection container to minimize the amount of water that spills inside the well house, while being sure that the well pump is engaged while collecting the sample.

6. Make sure the water is turned off to flowerbed in front of house before leaving.

2.2.6.12   JW-26

1. Well is located through the second gate to the left in a well house. Push the first gate open and slide through. (Appendix B, Figure JW-26)

2. Use water hose to purge water until pump engages, will have to listen and/or feel the water line to detect whether the well pump is running.

3. Purge at wellhead tap. Record pH, temperature, and conductivity readings until parameters stabilize, record approximate gallons purged.

4. Disconnect water hose and collect sample from wellhead tap.

2.2.6.13   JW-27

1. Be sure to contact the well owner to schedule an appointment and advise her you will be arriving. The dog must be contained prior to sampling as the dog may bite.

2. Well is located to the right of the house when facing it. (Appendix B, Figure JW-27.1)

3. In well house take cover off electrical box. Unplug electrical cord first to avoid electrical shock. Place toothpick at contact inside electrical box (see Appendix B, Figure JW-27.2) and this will engage well pump. Plug electrical cord back in. Connect the water hose to avoid flooding the well house.

4. Purge at wellhead tap. Record pH, temperature, and conductivity readings until parameters stabilize, record approximate gallons purged.

5. Remove water hose and collect sample from wellhead, using a container to minimize water running onto the floor of the well house.

6. Unplug the electrical cord, remove the toothpick, plug the electrical cord back in, and replace the cover on the electrical box. Make sure water faucet is turned off. Be sure that all items are left in the condition they were found upon arrival.

2.2.6.14   JW-29

1. Be sure to contact the well owner to schedule an appointment and advise her you will be arriving. The dog must be contained prior to sampling as the dog may bite.

2. The well is located to the right of house.

3. At the wellhead turn off the valve just under the faucet (Appendix B, Figure JW‑29), to make certain that the sample is coming directly from the well and not the pressure tank.

4. Purge at wellhead tap. Record pH, temperature, and conductivity readings until parameters stabilize, record approximate gallons purged.

5. Collect sample from wellhead.

6. Turn valve back on and leave everything in the same condition as it was found at arrival.

2.2.6.15   JW-30

1. The well is located behind house.

2. For this location the field sampling team will need a ladder. The well owner has one by the fence that can be used, climb up on the cistern and depress the float switch to engage well pump (Appendix B, Figure JW-30.1).

3. Purge at wellhead tap (Appendix B, Figure JW-30.2). Record pH, temperature, and conductivity readings until parameters stabilize, record approximate gallons purged.

4. Collect sample from wellhead tap.

5. Make sure float switch is free of obstructions, turn all water off, and return ladder. Leave everything in the condition it was found upon arrival.

2.2.6.16   LS-1

1. Bexar Metropolitan employees will unlock gate to provide access to well area for sampling and engage the well pump.

2. Well is located in gated area (Appendix B, Figure LS-1).

3. Purge at wellhead tap. Record pH, temperature, and conductivity readings until parameters stabilize, record approximate gallons purged.

4. Collect sample from wellhead.

2.2.6.17   LS-2

1. Bexar Metropolitan employees will unlock gate to provide access to well area for sampling and engage the well pump.

2. Well is located to the right after entering the gate (Appendix B, Figure LS-2).

3. 3. Purge at wellhead tap. Record pH, temperature, and conductivity readings until parameters stabilize, record approximate gallons purged.

4. Collect sample from wellhead.

2.2.6.18   LS-3

1. Bexar Metropolitan employees will unlock gate to provide access to well area for sampling and engage the well pump.

2. Well is located southwest of LS-2 (Appendix B, Figure LS-3).

3. Purge at wellhead tap. Record pH, temperature, and conductivity readings until parameters stabilize, record approximate gallons purged.

4. Collect sample from wellhead.

2.2.6.19   LS-2/LS-3 GAC

1. GAC unit for wells LS-2 and LS-3 is located inside gated area where LS-2 is located, in building constructed of white canvas. Bexar Metropolitan employees will have the key (Appendix B, Figure LS-2/LS-3 GAC.1).

2. Collect two post-GAC samples from between filtration canisters: a. Sample LS-2/LS-3-A2 is collected from sample valve labeled �SAMPLE VALVE EFFLUENT FROM UNITS 1 & 2� (Appendix B, Figure LS‑2/LS‑3 GAC.2). b. Sample LS-2/LS-3-A1 is collected from sample valve labeled �SAMPLE VALVE EFFLUENT FROM UNIT NO. 1� (Appendix B, Figure LS‑2/LS‑3 GAC.3).

3. Record gallons used on flowmeter for each GAC unit.

2.2.6.20   LS-4

1. Bexar Metropolitan employees will unlock gate to provide access to well area for sampling and engage the well pump.

2. Well is located in gated area (Appendix B, Figure LS-4).

3. Purge at wellhead tap. Record pH, temperature, and conductivity readings until parameters stabilize, record approximate gallons purged.4. Collect sample from wellhead.

2.2.6.21   LS-5

1. Turn water on outside of the house located at 7579 Curres Rd., this will drain pressure tank to allow well pump to engage.

2. Confirm whether power is on at well, it is located on the telephone pole closest to the well. (Appendix B, Figure LS-5). Purge at wellhead tap. Record pH, temperature, and conductivity readings until parameters stabilize, record approximate gallons purged.

3. Collect sample from wellhead.

4. Leave power as it was upon arrival; turn off water at separate house when finished.

2.2.6.22   LS-6

1. Well is located next to cistern, look for gray GAC house.

2. Purge at wellhead to the left of GAC house (Appendix B, Figure LS-6.1). Record pH, temperature, and conductivity readings until parameters stabilize, record approximate gallons purged.

3. Collect pre-GAC sample directly from wellhead (Appendix B, Figure LS-6.2).

4. Collect post-GAC sample from the sample port in bottom of GAC house between the two canisters.

5. Record gallons used from flowmeter at top inside the GAC unit.

6. Temporarily cut off water into GAC unit to change the prefilters:

1. Turn red valve in the upper left corner of unit to the off position.

2. Unscrew both blue prefilter canisters and change filters if dirty.

3. Screw filters back on, turn valve back on and check for leaks.

4. Make sure unit is functioning properly before leaving; check sample ports to make sure water is running through the system.

7. Leave everything as it was upon arrival, except if the GAC system was bypassed or disconnected. Report any tampering with the system or apparent leaks to CSSA Environmental Office and/or Carbonair for repair.

2.2.6.23   LS-7

1. Well is located on south side of Curres Rd., look for the GAC unit, just behind the residence (Appendix B, Figure LS-7).

2. Purge at wellhead tap located behind GAC unit. Record pH, temperature, and conductivity readings until parameters stabilize, record approximate gallons purged. Take pre-GAC sample from wellhead tap.

3. Post-GAC sample is collected from sample port at bottom of GAC unit between canisters (Appendix B, Figure LS-6.2).

4. Record gallons used from flowmeter at top inside the GAC unit.

5. Temporarily cut off water to change prefilters:

1. Turn red valve in the upper left corner of unit to the off position.

2. Unscrew both blue prefilter canisters and change filters if dirty.

3. Screw filters back on, turn valve back on and check for leaks.

4. Make sure unit it functioning properly before leaving; check sample ports to make sure water is running through the system.

6. Leave everything as it was upon arrival, except if the GAC system was bypassed or disconnected. Report any tampering with the system or apparent leaks to CSSA Environmental Office and/or Carbonair for repair.

2.2.6.24   OFR-1

1. Well is located behind house, follow road to right at first fork, then to left at second fork, look for blue pressure tank (Appendix B, Figure OFR-1).

2. Unhook water hose at wellhead.

3. Purge at wellhead tap. Listen for pump to engage and/or feel the water line to ensure pump is running. Record pH, temperature, and conductivity readings until parameters stabilize, record approximate gallons purged.

4. Collect sample at wellhead tap.

5. Reconnect water hose and leave everything as it was upon arrival. Sometimes the water is already running; the hose leads to a watering tub for cattle in the pasture.

2.2.6.25   OFR-3

1. Contact the well owner or his employees to arrange access to the area of the wellhead, it is normally locked.

2. Well is located to the left of the building and GAC unit is located to the right of the building when facing the building from the parking lot.

3. Purge at wellhead (to the left of the building) and record pH, temperature, and conductivity readings until parameters stabilize, record approximate gallons purged.

4. Collect sample from wellhead tap (left of building).

5. Post-GAC sample is collected from inside the GAC unit (right of the building) from the bottom sample port between the canisters (Appendix B, Figure LS-6.2).

6. 6. Record gallons used from flowmeter at top inside the GAC unit.

7. Temporarily cut off water to change prefilters:

1. Turn red valve in the upper left corner of unit to the off position.

2. Unscrew both blue prefilter canisters and change filters if dirty.

3. Screw filter back on, turn valve back on and check for leaks.

4. Make sure unit it functioning properly before leaving; check sample ports to make sure water is running through the system.

8. Leave everything as it was upon arrival, except if the GAC system was bypassed or disconnected. Report any tampering with the system or apparent leaks to CSSA Environmental Office and/or Carbonair for repair.

2.2.6.26   OFR-4

1. Well is located behind the house, straight ahead when coming up the driveway (Appendix B, Figure OFR-4).

2. Turn on water at any outside faucet to drain the pressure tank.

3. Purge at the wellhead tap. Listen for pump to engage and/or feel the piping to detect whether the pump is running. Record pH, temperature, and conductivity readings until parameters stabilize, record approximate gallons purged.

4. Collect sample from wellhead tap.

5. Turn off all water faucets before leaving.

2.2.6.27   RFR-8

1. Well is located to the far left side of property, when facing the residence (Appendix B, Figure RFR-8).

2. Turn on water at any outside faucet to purge the pressure tank, well owner will usually assist with this.

3. Make sure well pump is engaged, can feel the ground vibrating under the concrete well pad when the pump is running.

4. Purge at wellhead tap. Record pH, temperature, and conductivity readings until parameters stabilize, record approximate gallons purged.

5. Collect sample from wellhead.

6. Turn everything off and replace trashcan over wellhead. Watch for scorpions or other insects.

2.2.6.28   RFR-9

1. Well is located on the left side of the driveway, by the house (Appendix B, Figure RFR-9).

2. Turn on the water outside of the house to purge pressure tank so well pump will engage.

3. Purge at wellhead tap. Record pH, temperature, and conductivity readings until parameters stabilize, record approximate gallons purged.

4. Collect sample from wellhead.

5. Turn water faucet off at house before leaving.

2.2.6.29   RFR-10

1. Well is located near the antenna tower, follow drive way to the right until the antenna tower is to the right, take a sharp left about 15 yards after tower.

2. The well has two GAC units running in parallel.

3. A switch to engage the well pump has been installed in GAC unit A between the carbon canisters (Appendix B, Figure RFR-10.1).

4. The pre-GAC sample will be collected from the wellhead located behind the GAC units.

5. Purge at wellhead tap. Record pH, temperature, and conductivity readings until parameters stabilize, record approximate gallons purged.

6. Collect pre-GAC sample from wellhead.

7. Two post-GAC samples are collected from sample ports at the bottom of each GAC unit between canisters, in the appropriate GAC unit A or unit B. (Appendix B, Figure RFR-10.2).

8. Record gallons used from flowmeter at top inside each GAC unit.

9. Temporarily cut off water to change prefilters:

1. Verify well pump is not running, if it is, make sure switch in GAC A is in off position then cut power at the telephone pole to the left of the GAC units.
2. Turn red valve in the upper left corner of each unit to the off position.
3. Unscrew both blue and clear prefilter canisters and change filters if dirty.
4. Also check back-up filters attached to the back of GAC unit A (Appendix B, Figure RFR-10.3).
5. Screw filters back on, turn power and red valves back on and check for leaks.
6. Make sure unit it functioning properly before leaving; check sample ports to make sure water is running through the system.

10. Leave everything as it was upon arrival, except if the GAC system was bypassed or disconnected. Report any tampering with the system or apparent leaks to CSSA Environmental Office and/or Carbonair for repair.

2.2.6.30   RFR-11

1. Well is located in a well house behind the main business office. Note: the door is not attached, but is leaning up against the doorframe opening. Move the door aside and watch your head, this is a low doorframe.

2. Purge at faucet immediately outside of well house. Record pH, temperature, and conductivity readings until parameters stabilize, record approximate gallons purged.

3. Take pre-GAC sample from wellhead.

4. Post-GAC sample is collected from sample port in the corner after it has run through both canisters.

5. Record gallons used from flowmeter at top inside the GAC unit.

6. Temporarily cut off water to change prefilters: (Appendix B, Figure LS-6.2)

1. Turn red valve off located just before first prefilter.

2. Unscrew both blue prefilter canisters and change filters if dirty.

3. Screw filter back on, turn valve back on and check for leaks.

4. Make sure unit it functioning properly before leaving; check sample ports to make sure water is running through the system.

7. Leave everything as it was upon arrival, except if the GAC system was bypassed or disconnected. Report any tampering with the system or apparent leaks to CSSA Environmental Office and/or Carbonair for repair.

2.2.6.31   RFR-12

1. This well should be sampled in conjunction with I10-2 to avoid bothering the well owner more than once.

2. Contact Steve from AAA Stowaway to accompany you to RFR-12, which is located to the right of the Pico Diamond Shamrock gas station when facing the station.

3. Enter the gated area, then well house.

4. Pull the existing water hose out of the well house and turn on water to engage the well pump. If pump does not come on, climb on top of cistern and push down float switch to engage the well pump. (Appendix B, Figure RFR-12.1)

5. Record pH, temperature, and conductivity readings until parameters stabilize, record approximate gallons purged. Readings are taken from water hose purge water and the sample is collected from the faucet in the corner closest to the well head. (Appendix B, Figure RFR-12.2)

6. Turn off all water and return the well house to the condition it was in upon arrival.

2.3 - Groundwater Sample Identification

To keep groundwater sampling information consistent, a naming convention was established as part of the DQOs. Consistent use of a standardized naming convention allows for better database management and ease of use. Nomenclature has been established to distinguish the following data types:

Table 3 lists valid sample identification codes for wells currently sampled, in addition to the new wells described in this work plan. All sampling locations have a geographic prefix followed by an alphanumeric designator. The following are examples of geographic coding:

Some off-post well locations are treated with one or more GAC units. The GAC units are designated as unit �A� or unit �B.� There is currently only one location with multiple GAC systems (RFR-10). Except for the system at RFR-10, the GAC units consist of two canisters (#1 and #2) that are operated in series, with sampling ports following each canister. Occasionally, samples are collected after individual canisters to evaluate their condition and monitor for COC breakthrough. Other infrequently collected samples include entry point (EP) samples collected at public supply wells, and water samples collected from a point-of-use faucet (tap) such as in a kitchen or washroom.

It is imperative that sampling conventions be applied consistently. For those occasions when a new sampling point does not fit one of the valid sample identifications (e.g., a new GAC system or a newly added well), the field sampling team will contact the project or task manager to assign a new unique sample identifier.

Table 3 - Valid Groundwater Sample Identifications
On-post Wells

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