Addendum 2_Questions _ Responses_Frisco Groundwater Well Development Study.pdf

Addendum 2

January 25, 2025

Town of Frisco Frisco Groundwater Well Development Study Responses by: Christopher McGinnis, Public Works Director/Town Engineer

Questions, comments and clarification requests for plan holders:

Question 1. Bi-weekly meetings with Town Staff are required in the scope. Can you confirm that the intent is a meeting every two weeks and not twice a week?

Response: A meeting with Town staff will be required once every two weeks. Meetings may be virtual.

Question 2. Will the selected consultant have access to existing data with respect to PFAS and EDB concentration levels in Well 7 and other city wells?

Response: Correct, the Consultant will be provided all existing data with respect to PFAS and EDB after contract award.

Question 3. Do you have a suite of water quality parameters that the Town would like to be tested or are you requesting that the selected consultant provide a recommendation of those parameters as part of the Scope.

Response: The Consultant shall provide a testing recommendation to ensure compliance with EPA and CDPHE requirements. At a minimum, expected testing includes PFAS, Fluoride, Inorganics, Nitrates, Nitrites, Volatile Organics, Synthetic Organics, Uranium, and Radium.

Question 4. Other than the well drilling contractors, are we allowed to subcontract or partner with other firms for some subtasks?

Response: The Consultant may subcontract/subconsultant any subtasks desired. Consultant shall list any subcontractors/subconsultants in proposal.

Question 5. I In the Project Goals section, a bullet point states: "Complete well test hole drilling at the preferred well site. Determine well capacity well drawdown, and water quality at the site" These are clear and feasible goals. The next sentence states "Well to be capable of producing 650 gpm." We understand that this is the ultimate goal for the production well which is to be drilled later based upon our findings at the test well. We cannot guarantee that the test well will produce 650 gpm. Nor can we guarantee that the subsequent production well will yield 650 gpm. We would like some clarification on this issue.

Response: The Town understands that a specific yield rate cannot be guaranteed for the well.

650 gpm is the desired minimum rate for the well and Town expects Consultant to complete testing and recommendations on sites which indicate that 650 gpm is achievable. However, the Town understands that Consultant cannot provide a guarantee that production well will produce 650 gpm.

Question 6. Can pumping test water be directly discharged to the Town’s storm drains or sanitary sewers?

Response: The Town does not own the sanitary sewers and therefore pumping water cannot discharge directly to sanitary sewer. The Town will allow water to be discharged to storm sewer.

Consultant shall be responsible for ensuring any CDPHE dewatering requirements are met.

Question 7. Does the Town have an existing distribution system model?

Response: The Town has mapping and schematics of the distribution system, but it does not currently have a pressure/flow model of the distribution system.

Question 8. Does the Town of Frisco require water distribution system pressure and flow modeling as part of this response?

Response: The Town does not require water distribution system pressure and flow modeling as part of this response.

Question 9. If the project award is delayed, will the rest of the schedule be similarly delayed to preserve the duration required to perform the work?

Response: If the project award is delayed, the schedule will be extended by an equal or greater duration to ensure project duration is not shortened. Proposers are also encourage to propose alternate schedules if the schedule proposed in the RFP is determined not to be feasible.

Question 10. Does the Town want the test well to be capable of producing 650 GPM?

Response: The Town desires the test well and ultimately the production well to be capable of producing 650 GPM.

Question 11. Are the potential well sites mentioned in the bulleted list at the bottom of page 3 of the RFP, the same as those identified in Exhibit C? If these potential well sites are different, can you provide data on the expanse/areas of the new potential well sites?

Response: Many of the well sites are the same between page 3 and those identified in Exhibit C.

The list on page 3 was modified with Addendum 1 so the full list of potential sites include:

• Town open space parcels located near Meridian Loop (Parcel D on Exhibit C)

• Frisco Peninsula Recreation Area (Town Parcel)

• Frisco Peninsula Recreation (Forest Service Parcel)

• Right of Way near 4th Ave

• Parcels south of Frisco

• Site B

• Exiting Abandoned Well near 3rd Ave and Tenmile Creek (Well 3)

See red circled areas below for an approximation of these sites. These sites are a general recommendation of potential sites based on Town knowledge and the previous study. Town expects Consultant to make final recommendations which would either add additional areas to the list or remove sites listed above.

Question 12. Can the Town provide well logs for wells #5, #6, and #7? Additionally, information on the drilling companies who drilled wells #5, #6, and #7 would be appreciated if that information is not already provided in the drill logs.

Response: See attachments at the bottom of this document for well logs.

Question 13. Can the Town provide average annual flows (only maximum rates are provided in the

RFP)?

Response: Wells #5-7 have the following average annual flows. Please note that the average flow from Well #7 is from 2021, as Well #7 has not been operated in recent years due to PFAS contamination.

• Well #5 - 92 million gallons per year (175 gpm annualized average)

• Well #6 – 98 million gallons per year (186 gpm annualized average)

• Well #7 – 120 million gallons per year (228 gpm annualized average)

Question 14. Two dates have been posted on the RFP for a due date. Could you confirm if the proposal due date will be February 2 or 3?

PRA sites. Locations east of Well 7 near existing water storage tank.

Response: Proposals will be due at 5:00 pm on February 3rd, 2025.

Question 15. The PFAS study will greatly affect the location in which we could put down a new well.

Will these results be shared with us if that investigation is to take place and is there a suspexted source of the PFAS?

Response: The Town’s Well #7 tested positive for several PFAS compounds. There has not been a further investigation conducted to try to determine the extent or origin of the PFAS contamination Consultant may propose further PFAS investigation or make recommendations against test wells in the vicinity of the PFAS contamination.

Question 16. Has there been any other detections of PFAS near Well #7? For example, has the ISFS tested their water well at the Peak One Campground? Could we work with the USFS to test their wells to understand the extent of the PFAS?

Response: The Town is not aware of PFAS being detected in the USFS well, but it is not known at this time if the USFS has tested their well. The Town is not aware of other PFAS contamination in other wells in the vicinity of Well #7. The Phase 1 study portion of the project could include checking other well data for PFAS contamination. Additionally, the Town would be open to working with the USFS to test their well to understand PFAS contamination extent.

WELL #5 DEPTH MEASUREMENTS

Date Static Depth Pumping

Depth 9/6/19 23.3

9/19/19 22.8

WELL 6 static -feet

WELL 6 dynamic -feet

9/5/2019 -34.8

9/17/2019 -69.4

10/31/2019 -27.5

12/3/2019 -27.1

12/20/2019 -25.5

12/30/2019 -26.5

1/6/2020 -27.1

1/24/2020 -26.1

2/4/2020 -26.2

2/11/2020 -68.7

2/12/2020 -26.4

2/18/2020 -26.6

2/28/2020 -26.1

3/2/2020 -26

3/16/2020 -26

3/30/2020 -25.7

4/4/2020 -26.4

4/20/2020 -25.2

4/22/2020 -26.1

5/4/2020 -25.2

5/11/2020 -54.8

5/19/2020 -69.9

5/28/2020 -26.2

6/10/2020 -69.8

6/17/2020 -70.4

6/26/2020 -70.11

7/9/2020 -71.9

7/30/2020 -68.1

11/17/2020 -27.1

12/4/2020 -27.6

12/8/2020 -70.1

12/21/2020 -26.8

1/6/2021 -27.4

1/15/2021 -21.1

1/25/2021 -27

1/29/2021 -72.9

2/1/2021 -28

2/23/2021 -28.5

3/4/2021 -68.1

3/19/2021 -35.9

3/26/2021 -28.5

4/13/2021 -27.8

5/10/2021 -27.1

5/14/2021 -69.3

6/1/2021 -72.8

6/2/2021 -27.9

6/18/2021 -28.9

6/28/2021 -72.4

7/6/2021 -28.4 -65.2

7/14/2021 -72.8

7/22/2021 -72.8

8/9/2021 -27.2

8/23/2021 -72.1

8/24/2021 -28

9/8/2021 -27.7

9/10/2021 -72.3

9/24/2021 -27.9

10/12/2021 -27.6

10/20/2021 -66.1

Table 1

WELL 6 static - feet WELL 6 dynamic - feet

-80

-60

-40

-20

9/5/2019 11/5/2019 1/5/2020 3/5/2020 5/5/2020 7/5/2020 9/5/2020 11/5/2020 1/5/2021 3/5/2021 5/5/2021 7/5/2021 9/5/2021

D ep th fe et

WELL 6 static feet WELL 6 dynamic feet

WELL 7 static -feet

WELL 7 dynamic -feet GPM

9/6/2019 -58.3 275

9/15/2019 -58.5 275

10/18/2019 -62.1 275

10/31/2019 -60.2 275

11/11/2019 -62.2 275

12/3/2019 -63.9 275

12/13/2019 -64.2 275

12/30/2019 -64.5 275

2/5/2020 -65.1 250

2/11/2020 -64.5 225

2/20/2020 -64.7 225

2/26/2020 -64.9 225

3/16/2020 -64.9 225

3/30/2020 -64.9 225

4/2/2020 -59.4

4/14/2020 -59.1

4/20/2020 -64.4 225

4/22/2020 -59.1

5/4/2020 -62.9 225

5/12/2020 -57

5/19/2020 -61.2 225

5/31/2020 -60.4 225

6/10/2020 -61.5 300

6/19/2020 -60.7 300

6/26/2020 -62.9 300

7/6/2020 -59.6 300

7/30/2020 -62 300

11/15/2020 -63.6 250

12/4/2020 -64.6 250

1/13/2021 -67.4 250

1/18/2021 -67 250

1/25/2021 -71.5 250

1/28/2021 -63.1

2/2/2021 -62.7 -70.7 300

3/1/2021 -71.9 300

3/8/2021 -72.9 300

3/19/2021 -71.5 300

3/26/2021 -71.3 200

4/1/2021 -71.5 200

4/5/2021 -67.2

4/6/2021 -67.1

4/12/2021 -71.9 200

4/26/2021 -66.9 200

5/10/2021 -71.6 200

5/27/2021 -70.3 200

Table 1

6/21/2021 -66.4 250

6/28/2021 -64.9 250

7/6/2021 -63.5 250

7/9/2021 -57

7/15/2021 -62.7 250

7/20/2021 -61.6 250

8/9/2021 -60.1 250

8/20/2021 -60.1 250

9/7/2021 -61.5 250

9/14/2021 -62.5 250

9/24/2021 -64.4 250

10/1/2021 -59.3

10/12/2021 -59.4

10/14/2021 -65.5 250

10/27/2021 -67.7 250