DIVISION FIVE - Soquel Creek Water · PDF fileDIVISION FIVE . TECHNICAL ... amp;_PLANS/Division_One.pdf . ... • Temporary piping and valves for well pump discharge

DIVISION FIVE TECHNICAL SPECIFICATIONS

TO REHABILITATE SOQUEL CREEK WATER DISTRICT’S

MAIN STREET WELL AND

REPLACE PUMPING EQUIPMENT SECTION 1. SCOPE OF WORK

Soquel Creek Water District (District) seeks to rehabilitate an existing 16-inch reduced to 12-inch-diameter, 656-foot-deep well located at 3325 Main Street in Soquel (Figure 1) via mechanical and chemical means to restore well performance. The well has five separate 12-inch-diameter wire-wrap stainless steel screens all with a 0.075-inch slot size. The screen intervals are summarized in the table below. A schematic of the well is shown on Figure 2. Note that video surveys indicate all screens are approximately 4 feet deeper than depicted on Figure 2.

Main Street Well Screens Depth below Ground Surface

Uppermost Screen 236 – 250 feet 282 – 380 feet

428 – 452 feet 476 – 500 feet

Lowermost Screen 548 – 648 feet Specific capacity data collected by the District suggest that since its completion in 1986, the Main Street well has lost almost 50 percent of its original performance. Recent testing of the produced water by the District revealed the presence of both slime, sulfate-reducing, and iron bacteria. The loss of performance and change in water quality are both indicative of significant biological fouling of the well. If deemed necessary by the District or its representative, the Contractor will also furnish and install a new well pump and, if required, pump column, etc. in the Main Street well per Consultant’s specifications. The specifications for the well pump and column will be provided to the Contractor approximately two weeks after the aquifer test following rehabilitation has been completed.

Soquel Creek Water District Main Street Well Rehabilitation and Pump Replacement Division 5 Page 1 of 13

The Contractor shall provide all equipment, labor, chemicals, and temporary storage facilities to complete the work outlined in these specifications and as directed by the District or its representative.

Figure 1: Well Location


Figure 2: Main Street Well Construction

NOTE: VIDEO SURVEYS INDICATE ALL SCREENS APPROXIMATELY 4 FEET DEEPER


SECTION 2. QUALIFICATIONS OF CONTRACTOR

Contractor shall be familiar with all aspects of the work outlined in these specifications and shall possess a C-57 Contractors license. Contractor shall have a minimum of five years’ experience in well servicing and rehabilitation work and shall provide a minimum of three references of similar work completed within the last three years to District at their request. SECTION 3. COMPLIANCE WITH DISTRICT’S STANDARD SPECIFICATIONS

As applicable, all work will be performed under the terms and conditions outlined in Division 1 of the District’s Standard Specifications. These specifications list insurance requirements and contracting procedures. These specifications are available at the District’s web site. www.soquelcreekwater.com/Construction/STD_SPECS_&_PLANS/Division_One.pdf

SECTION 4. COMPLIANCE WITH AWWA STANDARD C65-13, DISINFECTION OF WELLS

As applicable, work will be performed in accordance with Section 4 of the American Water Works Association (AWWA) Standard C654-13.

SECTION 5. COMPLIANCE WITH APPLICABLE LAWS AND REGULATIONS

Contractor shall perform all work in strict accordance with all Federal, State, and local regulations, including those applying to the handling, transportation, and disposal of chemicals used or produced on the project. Contractor shall also obtain all permits, if any, required for the performance of the work outlined in these specifications. SECTION 6. SAFETY

Job site safety, both during and after working hours, is the sole responsibility of the Contractor. The Contractor, his employees and subcontractors shall be familiar with and comply with all applicable safety regulations and guidelines relating to the transportation, handling, and disposal of the chemicals to be utilized for the work as well as other aspects of the work, including electrical and mechanical safety guidelines and regulations. The Contractor shall also provide for and ensure public safety around the site both during and after work hours. In addition to personal safety equipment for project personnel, the Contractor shall provide and


maintain onsite the necessary equipment and materials for spill containment, neutralization, and cleanup of the chemicals utilized or produced during the project work. If the District or their representative determines that any of the safety measures or safety equipment onsite are inadequate or inappropriate he shall stop all work until the safety issue is corrected. No payment for standby time or equipment rental shall be made for such delays in the work. SECTION 7. CONTRACTOR’S EQUIPMENT

The Contractor shall provide all necessary equipment, tools, and appurtenances for the timely completion of the work. Contractor's equipment shall be in complete and safe operating condition, and shall be appropriately maintained and operated during the project. The Contractor shall be solely responsible for the condition of his equipment and shall maintain an inventory of necessary spare parts for the timely repair of equipment in the event of a failure or breakdown. No payment shall be made for standby time or equipment rental caused by a breakdown or failure of the Contractor's equipment. Equipment necessary for the work shall include, but not be limited to the following items:

• 12-inch diameter nylon “wire” brush block (weighted),

• Well pump removal rig,

• 10-inch-diameter nominal diameter bailer,

• 12-inch-diameter double surge block with chemical injection port,

• Chemical mixing tanks,

• Zone Pumping Isolation Tool – Electric Pump coupled to perforated pipe with 12-inch-diameter swabs,

• Portable storage tanks for storage and neutralization of well discharge fluids. Tanks shall consist of two 18,000+ gallon “Baker®” type tanks,

• Trash pumps for transferring fluids between tanks and circulating fluid within tanks,

• Temporary pump for removal of rehabilitation chemicals and well development (200 gpm capacity),

• Temporary test pump for 8-hour aquifer test (1,000 gpm capacity), and


• Temporary piping and valves for well pump discharge and to storage tank, sewer, and Soquel Creek.

Contractors pump rig shall be capable of lifting the bailer or surge block at a minimum velocity of three (3) feet per second at the bottom of the well. Due to the proximity of neighboring residential properties, equipment used by Contractor should be able to achieve a noise level of 85 decibels at the property boundary.

SECTION 8. MATERIALS

The following materials shall be utilized in the chemical treatment and disinfection of the well. The quantities of the chemicals listed are estimated based on existing water levels and well construction. The acids used must be food grade. The Johnson NuWell products are NSF approved for use in drinking water wells so any substitutions must be NSF 60 approved. No substitutions of chemical type shall be allowed without the prior written approval of District.

Table 1: Chemical Requirement Estimate

Chemical Purpose Quantity

Hydrochloric acid (30% wt), Inhibited pH Reduction/scale removal 330 gallons

Hydroxyacetic (glycolic) acid (70% wt) Biocide 120 gallons

Johnson NuWell 310 (or approx. equiv) Dispersant 12 gallons

Johnson NuWell 400 (or approx. equiv) Surfactant 12 gallons Calcium Hypochlorite (HTH), 65% available

chlorine Disinfection 136 pounds

Johnson NuWell 410 (or approx. equiv) Chlorine enhancer 9 gallons The Contractor shall also provide suitable mixing tanks, transfer pumps, and agitators as necessary to accurately prepare and inject the chemicals. The Contractor shall, at the completion of the work, remove all unused chemicals and shall legally dispose of all empty chemical containers or return them to the manufacturer. The Contractor shall obtain OSHA Material Safety Data Sheets (MSDS) for all chemicals used and have copies available onsite at all times.


SECTION 9. REDEVELOPMENT PROCEDURE

Contractor shall, under the direction of the District or their representative, perform both mechanical and chemical development work on the well to remove deleterious material from the casing and screen. The work shall be performed according to the following general schedule, with allowances for the effectiveness of treatment as determined by the District.

WORK SCOPE Task 1 - Mobilize equipment and remove existing well pump.

Task 2 - Video the entire length of the well using a reputable downhole video contractor.

Task 3 - Establish on-site fluid handling and storage facilities. Tankage will be used for fluid storage, neutralization, and dechlorination. Tankage shall be placed within the area enclosed by the existing fences. Tankage shall consist of two 18,000+ gallon tanks. Tanks shall be connected to the work area and each other by temporary piping.

Task 4 - Wire brush well screens using weighted wire brush for period of four (4) hours.

Task 5 - Mix chemicals in appropriate mixing tank. Chemicals shall be mixed in the following ratios:

To each 1,000 gallons of water add:

55 gallons Hydrochloric acid, inhibited (30% wt) 20 gallons Hydroxyacetic (glycolic) acid (70% wt) 2 gallons Nu-Well 310 Dispersant 2 gallons Nu-Well 400 Surfactant

Task 6 - Inject acid mixture into well. Proportional amounts of the mixture shall be dispensed for each screen section through the surge block and worked into the screen/formation through vigorous surging with the block before proceeding to the next section. After chemical is injected, swab entire screened interval to work chemical into screen/formation for a total of eight (8) hours, or as directed by District. Allow chemical mixture to remain in well for next 2 days.


Task 7 - Return to site every day for next 2 days. Mix chemicals by moving bailer or surge block through screened sections for period of 1 hour per day.

Task 8 - Install temporary pump capable of minimum discharge rate of 200 gpm against TDH of 700 feet. Pump can be connected to existing power at site. Pump will be coupled to an isolation development tool (two tight-fitting swabs separated by a perforated pipe of 5 to 10 feet) to allow focused zone pumping. The check valve on the pump must be removed to allow injection of chlorine solution in Task 10. Pump/development tool assembly must be movable and moved through the screened interval while pumping. Contractor shall flush the well water into the tank at a pumping rate to be determined by the District or their representative. Flushing will be deemed complete when pH of water reaches 6 and discharge is clear.

Task 9 - As the storage tanks fill or after well flushing is complete, Contractor shall neutralize well discharge prior to disposal. Fluids must be neutralized to a pH of approximately 7 prior to disposal to the on-site sewer located at the southeast corner of the washwater tank.

Task 10 - Upon completion of the well flushing, the Contractor shall disinfect the well casing using HTH in sufficient quantity to achieve a 1,000 parts per million (ppm) chlorine dose. Chlorine solution shall be premixed in a tank with pH adjusted to 7.5 to 8.0. Solution will be surged into the screen with a pump. After disinfection, the well shall be flushed after 24 hours. Discharge of chlorinated water shall be to on-site tankage where it will be dechlorinated with sodium thiosulfate or similar method and then discharged to the washwater tank or directly to the on-site sewer.

Task 11 - A second round of zone pumping and redevelopment will follow chlorination. Prior to inserting the pump/development tool assembly in the well, it shall be disinfected by spraying exposed areas with a solution having a chlorine residual of not less than 200 ppm. The pump/development tool must be movable and moved through the screened interval while pumping. Contractor shall flush the well into the tank at a pumping rate to be determined by the District or their representative. Flushing will be deemed complete when there is no chlorine residual and discharge is clear. Fluids disposal will be to the on-site sewer grate located at the southeast corner of the washwater tank via the temporary storage tanks.


Task 12 - Re-video the well to establish visual results of mechanical and chemical development.

Task 13 - Furnish and install test pump and appropriate piping, and conduct eight hour aquifer test. Prior to inserting the test pump in the well, it shall be disinfected by spraying exposed areas with a solution having a chlorine residual of not less than 200 ppm. The test pump shall be capable of achieving discharge rates of up to 1,000 gpm with an intake setting of approximately 250 feet. Pumped water will be discharged directly from the well to the nearby Soquel Creek.

Task 14 - After completion of the aquifer test, remove test pump. Demobilize Contractor’s equipment, remove storage tanks and remove all rubbish, empty containers, and waste material from site. Dispose of District’s well pump and column pipe to be replaced.

Task 15 - Furnish and install a new well pump and column pipe per the Consultant’s specifications. The specifications for the new pump will be provided to the Contractor approximately two weeks after the completion of Task 14. Only column pipe below the pumping groundwater level is expected to need replacement (60 feet of pipe). For bidding purposes, an allowance of $50,000 is included in the bid schedule to furnish and install the well pump and column pipe. Column pipe and tube may need steam cleaning. The bid schedule allows for 8 hours for this subtask, if needed. All permanent equipment and material to be installed in the well shall be disinfected just before installation. This shall be done by spraying exposed areas with a solution having a chlorine residual of not less than 200 ppm.

Task 16 - Final disinfection of the well after the District’s new pump has been installed shall be achieved using a chlorine solution of HTH or sodium hypochlorite together with a chlorine enhancer. Chlorine shall be used in sufficient quantity to achieve a 200 ppm chlorine dose. Pre-mix the solution in a tank starting with adding the required amount of chlorine enhancer to water. The pH of the solution should be between 4.5 and 5 before adding the HTH or sodium hypochlorite. All mixing should be done in a well-ventilated area. The chlorine solution pH shall be adjusted to 7.5 to 8.0 before introducing it into the well. Solution will be surged into the screen with a pump. After disinfection, the well shall be flushed after leaving it in the well overnight. Discharge of chlorinated water shall be to on-site tankage where it will be dechlorinated with sodium


thiosulfate or similar method and then discharged to the sewer. Demobilize Contractor’s equipment, remove all rubbish, empty containers, and waste material from site.

SECTION 10. WELL DISCHARGES

Three different discharge locations will be used during the rehabilitation and aquifer testing of the Main Street well.

1. Discharges with chemicals and chlorine will be via the temporary storage tanks to the on-site sewer (Tasks 8, 9, 11 and 16). Disposal to the sewer will likely be limited due to pipe capacity at peak sewer discharge periods. For example, in the morning until 11 a.m., discharge may be limited to 50 gpm, and increased to 150 gpm between 11 a.m. and 4 p.m. The sewer discharge shall be continuously flow metered and periodically monitored for pH. The District will be responsible for obtaining a special sewer discharge permit from the Santa Cruz County Sanitation District.

2. Discharges to the washwater tank will be only after initial disinfection (Task 10).

3. During the 8-hour aquifer test, well discharge will be routed to Soquel Creek. Contractor shall provide a dissipater to mitigate bank erosion at the discharge location. The discharge shall be continuously flow metered. The discharge will be permitted by the Central Coast Regional Water Quality Control Board’s General Permit for Discharges with Low Threat to Water Quality (Appendix A). The District will be responsible for monitoring and reporting required by the General Permit.

SECTION 20-11. SCHEDULE

The Main Street Well is a critical part of the District’s production system. The work shall be performed such that the time that the well is off-line is minimized. The Contractor shall work consecutive 8-hour business days (daylight hours) to complete work as rapidly as possible. It is anticipated that work could be completed according to the following schedule:

Day Task

Day 1 Mobilize, Remove Existing Pump, Video Well (Tasks 1 and 2)

Day 2 Establish On-Site Fluid Handling and Storage Facilities and Mechanically Clean Well (Tasks 3 and 4)


Day Task

Day 3 and 4 Chemically Treat Well (Tasks 5 and 6)

Day 5 and 6 Chemical Contact Time (Task 7) Day 7 Zone Pump/Chemical Recovery/Redevelop (Tasks 8 and 9) Day 8 Chlorinate (Tasks 9 and 10) Day 9 Zone Pump/Redevelop (Task 11) Day 10 Video Well, Install Test Pump (Tasks 12 and 13) Day 11 Perform Aquifer Test (Task 13)

Day 12 Remove Test Pump and Demobilize (Task 14) Day 14 (not sequentially after Day 13) but after the new pump has been specified and purchased – Mobilize to site and install well pump per Consultant’s specifications (Task 15) Day 15 Final chlorination (Task 16)

SECTION 20-12. SITE CONDITIONS

The Main Street Well site is shown on Figure 3. There is adequate space for temporary tankage within the existing fencing, along the southern site boundary and west of the control building. SECTION 20-13. PAYMENT

Payment will be made according to the unit price schedule in the contract based on the actual unit quantities expended as determined by the District. Payment for lump sum items shall be made only upon satisfactory completion of the entire task.


Figure 3: Main Street Well Site Plan


REHABILITATION OF SOQUEL CREEK WATER DISTRICT MAIN ST. WELL UNIT PRICE BID

Task Item No.

Approximate Quantity

Task Description/Summary Unit Price Amount

1 Lump Sum Mobilization and District’s Pump Removal $ $

2 Lump Sum Video Well $ $

3 Lump Sum Fluid Storage and Handling System. Includes 10-day tank rentals

$ $

4 4 hours Wire Brush Well $ /hour $

5 Lump Sum Provide and Mix chemicals. Includes Chemical Costs, Labor, and Equipment for Injection, Complete in Place

$ $

6 8 hours Inject chemicals. Surge well with Double-Surge Block as Described in Section 9

$ /hour

$

7 2 hours Surge Well as Described in Section 9 $ /hour $

8 Lump Sum Install Temporary Pump/Development Tool. Swab and Remove Chemical Solution from Well

$ $

9 Lump Sum Neutralize Well Effluent as Described in Section 9, Including all Labor, Equipment, and Chemicals

$ $

10 Lump Sum Disinfect Well as Described in Section 9, Including all Labor, Equipment, and Chemicals

$ $

11 Lump Sum Pump/Redevelopment Well $ $

12 Lump Sum Video Well $ $

13A Lump Sum Furnish and Install Test Pump and Appropriate Piping, and Remove Test Pump and Piping

$ $

13B 8 hours Pump Well for Eight (8) Hours $ /hour $

14 Lump Sum Demobilize Contractor’s Equipment, Including Removal of Empty Containers, Waste Disposal and Site Cleanup as Described in Section 9, Dispose of Well Pump and Column Pipe if Replaced

$ $

15A Lump Sum Furnish and Install New Well Pump and Column Pipe below the Pumping Groundwater Level

Allowance $ 50,0000

15B 8 hours Steam Clean Column and Tube $ /hour $

16 Lump Sum Final Well Disinfection as Described in Section 9, Including all Labor, Equipment, and Chemicals

$ $

A. % (Percent) Contractor’s Markup over Cost for New Pumping Equipment, and Additional Materials or Equipment Rental if Requested by the District

$ $

Total bid Price of Items 1 through 16 $

In words:


APPENDIX A

General Permit for Discharges with Low Threat to Water Quality

Soquel Creek Water District Main Street Well Rehabilitation and Pump Replacement












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DIVISION FIVE - Soquel Creek Water · PDF fileDIVISION FIVE . TECHNICAL ... amp;_PLANS/Division_One.pdf . ... • Temporary piping and valves for well pump discharge