A04_CRFY24_Performance_Based_Work_Statement_v1_3_updated_0001.docx

PERFORMANCE-BASED WORK STATEMENT MONITORING WELLS IN CEDAR RAPIDS, IOWA

I. GENERAL INFORMATION

A. Introduction (general description of services).

The United States Geological Survey (USGS) is in need of support from a well installation contractor for installation of four monitoring wells at two nested well sites for a project in Cedar Rapids Iowa. The two well sites are on the Cedar River alluvial floodplain generally within the footprint of the Cedar Rapids municipal well field. One deep well in each nest will be drilled about 20 feet into the bedrock with a 2-in diameter 10-ft long PVC screen and the second well will be drilled to about 40 ft deep and a 4-inch diameter10-ft long PVC screen installed within the alluvium. The depth to bedrock at each of the two drill sites is expected to be 55-65 feet. For budgeting purposes, assume 60 ft to top of bedrock and 80 ft TD for each bedrock well and 40 ft TD for each alluvial well. The alluvial wells will have natural filter pack and borehole allowed to collapse around the rise with the upper 10 ft of the annulus sealed to the land surface with bentonite. There are two options to this statement of work:

· Option 1: is for the two bedrock wells to be completed with 3-in diameter PVC riser and screens.

· Option 2: is for the two alluvial wells to have an engineered primary and secondary filter pack and bentonite annual seal to land surface. Also, core samples from the screen interval of the alluvial wells are to be collected.

B. Background

The City of Cedar Rapids, Iowa requires a sustainable supply of high-quality, municipal water to meet current and future demands to support economic development and population growth. Groundwater from the Cedar River alluvial aquifer is an important component of the City’s water supply. The City several municipal well fields that contain dozens of vertical wells and several high-capacity, Ranney lateral collector wells (fig. 1). The aquifer’s resilience has come into question in the recent past due to drought and increased pumping stresses. The US Geological Survey, in cooperation with the City of Cedar Rapids, has monitored water levels and water quality in the Cedar River alluvial aquifer using a network of monitoring wells established during past scientific investigations. These proposed 4 wells are an expansion of the existing network.

B1 Site location, conditions, and geology

The wells will be constructed at two locations within or near the Cedar Rapids well field on the floodplain of the Cedar River in Cedar Rapids, Iowa (Figure 1). The floodplain of the Cedar River is underlain by fluvial and glaciofluvial sands and gravels (the Cedar River alluvial aquifer) and adjacent uplands underlain by eolian (wind deposited sand and silt) sediment and glacial till. The alluvial aquifer at both locations is expected to be 55-65 ft (feet) thick. Bedrock beneath the site CRM-107 likely will be limestone/dolostone with minor shale stringers. Bedrock beneath site CRM-102 may consist of up to 10-20 ft of shale. If shale is encountered, the well depth will be extended to place the screen and filter pack beneath the shale zone.

C. Definitions/Applicable Documents

NA

D. Scope (state general purpose, objectives, magnitude).

The general project scope is for a contractor to install a total of four monitoring wells on the flood plain of the Cedar River in Cedar Rapids, Iowa. Wells CRM-107A and CRM-107B will be nested (one alluvium and one bedrock) just west of Edgewood Road, and wells CRM-102A and CRM-102B will be nested at a location about 2-miles further west in an undeveloped area north of Ellis Road (figure 1). The exact depth of the wells will be determined based on the depth to bedrock at time of drilling (ATD); however, the alluvial or “A” wells at both locations are planned to have the base of the screen at 40 ft deep within the alluvium and be completed using 4-inch diameter SH40 flush threaded PVC riser and screen with a natural collapse filter pack. The bedrock or “B” wells will be installed adjacent to the alluvial well and drilled about 20 feet into the underlying bedrock and be constructed using 2-inch diameter SH40 flush threaded PVC riser and screen. The bedrock borehole should be a minimum of 6-in diameter to allow a 2-inch annulus for adequate placement of filter pack and annular seal. For planning/budgeting purposes, assume the bedrock wells will have a total depth of 80 ft.

All wells will have a 10-ft long #10 slot PVC screen and above ground completions. There are two options: Option 1 for completion of the bedrock wells using 3-in diameter PVC riser and screen, and Option 2 for completion of the alluvial wells with engineered primary and secondary filter pack and bentonite annular seal to the land surface. Each bedrock well will have an 8-inch diameter lockable steel protective cover installed with its base at least 4-ft below land surface within concrete and a stickup of about 4 ft. The alluvial wells will have an extended steel protective casing to about 10 ft above the land surface to place the top of the PVC riser and protective cover above a 65,000 ft3/s flood flow of the Cedar River. The steel protective cover for alluvial wells should extend at least 7 feet below the land surface and the annulus between the outside of the steel and the borehole sealed with concrete and annulus between the PVC and steel protective casing filling with sand with several weep holes.

The contractor is responsible for obtaining utility clearance and confirming with Cedar Rapids Water Department locations of their private utilities in the event they are not specifically notified by the utility locate request. USGS will stake the location of each of the two well clusters in advance so Contractor can verify the area is suitable and request utility locate. Each bedrock monitoring well will have an engineered primary and secondary filter pack and bentonite chip/pellet plug above the well screen and bentonite grout or hydrated bentonite chips/pellet to the top of bedrock. Depending on Driller recommendation and geologic conditions at time of drilling (ATD), the remaining borehole annulus above the top of bedrock may be allowed to naturally collapse to within 10 ft of the land surface as the auger/temporary casing is removed and the remaining annulus to the surface sealed with bentonite. Alluvial wells will have a natural collapse filter pack and the borehole above the screen allowed to collapse natural with the upper 10 ft of annulus to the land surface sealed with bentonite. Any areas of stable borehole will be filled with bentonite chips or grout. Contractor will be required to develop the wells using surging and pumping. USGS will monitor turbidity of water pumped during development until purge water turbidity is <15 NTU, removal of 20 times the screen and filter pack volume plus 3 times water volume used in drilling or construction, or 2 hours of development time. Surge blocks, pumps, and hoses used in well development shall be clean and free of dirt/grease/contaminants and subject to inspection by USGS before use.

II. WORK REQUIREMENTS

A. Technical Requirements.

Contractor will install the four monitoring wells (2 wells per nested site) using standard methods for drilling in unconsolidated material and the underlying bedrock. It is anticipated the hollow stem auger or casing advance will be used for the alluvial wells. Mud rotary is not an acceptable method for the alluvial wells, but can be used to drill through the alluvium for the bedrock wells. Within the bedrock, use of mud methods is not desirable.

Mobilization will include all Contractor activities required to transport, assemble, and set up to drill including all materials needed for well construction and development, including all Contractor equipment, personnel, and services necessary to perform and support the work. Equipment will arrive at the work site clean and in good working order and subject to inspection by USGS. Mobilization and demobilization will also include Contractor activities required to dismantle and/or package all Contractor ’s equipment and personnel. Standby time will not be paid for delays due to Contractor mobilization, or delays caused by equipment breakdown, spills, or obtaining additional supplies.

1. Before mobilizing to the work site, the Contractor will secure underground utility clearance and verify the City of Cedar Rapids utilities have also cleared drill locations. USGS will stake well locations in advance and work with the landowner (city) to ensure Contractor has access to drill locations and the City can assist to ensure suitable access for Contractor equipment.

2. Contractor shall have suitable equipment to collect minimally disturbed samples (core, Shelby tube, or other) from within the screened interval of alluvial wells. Drill cuttings will be sufficient from the bedrock section of the boreholes.

3. For Option 2 (engineered filter pack for alluvial wells), Contractor shall ensure that heaving of alluvial materials does not occur inside casing/HSA when setting alluvial well screens and filter pack. This may require loading of the augers/casing with potable water to maintain a positive head slightly above that of the aquifer. USGS will work with the City to ensure contractor has local access to potable water for drilling and cleaning.

4. A USGS field geologist will oversee all drilling, core/ cuttings sampling, and well installation activities. Monitoring wells will be plumb, and the well riser and screen will be certified for potable and monitoring well use and be new and arrive at the site clean and sealed in original manufacturer packaging. Schedule 40, 4-in and 2-in (or 3-inch for option 1) diameter flush threaded PVC well riser and 10 foot long #10 (0.010 inch) slot size PVC well screens are required. Casing joints will have o-ring seals and a threaded bottom plug and centralizer will be placed at the bottom of the screen section. The top of the well riser will be fitting with an expandable top plug to prevent foreign objects or filter sand or bentonite from entering the well casing or screen during/after construction.

5. No drilling additives or grease/oils/lubricates can be used on any tooling or augers unless approved by the USGS field geologist. Mud rotary is not an acceptable method for the alluvial monitoring wells; however, mud rotary for drilling the alluvial part of the bedrock wells may be allowed. The concern is drilling mud affecting the water quality samples to be collected from these wells. Also, if mud rotary is used for the alluvial part of the bedrock wells, the spacing between the adjacent alluvial well may be increased to reduce the potential for drilling mud to affect alluvial water quality samples.

6. The PVC riser and protective cover of each bedrock well will extend about 4 feet above the land surface and at least 3 feet below land surface. The PVC riser and protective cover for the two alluvial wells will be extended to about 10 ft above the land surface and base be set at least 7 feet below land surface.

7. A lockable steel protective cover (minimum 8-in diameter) will be installed at each bedrock location extending to about 4-ft above land surface and 3 feet below land surface where it will be set in concrete. Alluvial wells will have 8-in protective steel casing extending about 10 ft above the land surface and 7 feet below land surface with a lockable plat/cover.

8. A 4 inch thick concrete pad will be poured extending 2 ft around the protective cover for each well.

9. Four minimum 8-ft long bollards will be installed around the concrete pad extending 4- feet above ground to protect the well from debris flow.

10. Drill /auger cuttings are required to be temporarily contained and removed; however, they may be spread out on the land surface around the well site to restore ruts, etc. at the discretion of the USGS field geologist.

11. Contractor is responsible for housekeeping at the work site and daily pickup and removal of trash/refuse generated during contractor activities and responsible for immediate cleanup of spills resulting from contractor operation (such as fuel or hydraulic oil leaks or spills).

12. Contractor will follow standard safe drilling practices and the USGS field geologist will have the authority to temporarily stop work if extreme unsafe practices are observed or leaks/spills are found until such can be remedied.

13. Contractor will have necessary equipment for well development including surge blocks and pump and discharge hose suitable for purging a sustained rate of at least 5 gallons per minute. Wells will be developed by alternating surging and purging to remove fines from the filter pack and accumulated sediment from the bottom of the well screen.

14. USGS will monitor turbidity during development purging and development will continue until a turbidity of <15 NTU is achieved, removal of 20 times the volume of the well screen and filter pack plus 3 times the amount of water used in drilling/construction, or two hours is reached.

15. Upon mobilization to the work site, work will proceed in a continuous manner with all work completed within 7 days from contractor arrival at the site except for weather delays. It is anticipated that all activities can be completed within 4 full workdays.

B. Acceptance Criteria

USGS will oversee all contractor activities to ensure well installation meet project objectives.

C. Deliverables.

Project deliverable will be two nested well sites each containing two monitoring wells: one 4-in diameter well about 40 ft deep screened in the alluvium and one 2-in (or optional 3-in diameter) well screened to about 20 feet below the top of bedrock. All well risers and screens will be schedule 40 PVC flush threaded and certified for potable water. Well screens will be #10 slot and 10 ft long. Wells will be free from obstructions with no offsets or bends and have properly secured lockable protective covers extending a minimum of 4- feet above the land surface for bedrock wells and about 10 ft above land surface for alluvial wells Each well will have 4 8-ft long bollards installed with 4 ft stickup. Mobilization to field site is expected within 45 days of award but this is negotiable depending on Contractor schedule and weather or streamflow conditions. Once Contractor has mobilized to the site, all activities to be completed within 7 days.

III. SUPPORTING INFORMATION

A. Period of performance will be within 7 days of mobilization to the work site. It is anticipated that contract will be awarded in late July 2024 with mobilization to the work site within 45 days. Mobilization date is negotiable depending on driller schedule and site and streamflow conditions. However, mobilization date will be agreed upon at time of contract award.

B. Government Furnished Property (GFP): NONE

C. The Contractor is required to have appropriate permits and licenses required by the State of Iowa before the contract is awarded.

D. Data Rights, Safety, Environment:

1. Contractor will complete any required permits and pay any fees for well installation.

2. Contractor will follow standard safe drilling practices and pick up and remove all trash generated by contractor activities at the work site. Contractor is responsible for immediate cleanup of any spills (fuel, oils, etc) resulting from contractor’s work.

3. Before contract award, Contractor will provide the name of any subcontractors, drill rig operator name and current license/permits.

4. USGS reserves the right to inspect/review and approve subcontractor qualifications and drilling equipment within 10 days of contract award and verification at time of mobilization. Contract may be suspended or terminated based upon inspection if deficiencies are found and not rectified within 14 days of written notification.

5. Drill operator and drilling company shall have a current license in good standing to drill/install monitoring wells in the State of Iowa and have no pending/outstanding notice of violations.

E. USGS Personnel will:

1. Secure permission from landowner for drilling activities (City of Cedar Rapids is the landowner)

2. Stake well locations in advance of Contractor contacting utility locate.

3. Provide a field geologist to oversee site operations, inspect lithology/drill cuttings to determine specific completion depths for the monitoring wells, and prepare a field geologic log of each well.

4. Provide geologists logs of well borings and final construction drawings of wells.

5. Provide monitoring of turbidity during well development.

Figure 1. General location of proposed drilling sites for nested wells CRM-102 and CRM-107 in Cedar Rapids, Iowa.

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