BID 2022-12 Clarifying Questions 3.pdf
PDF 205 KB Posted
- Attached to
- Barton Park Day Use Well Project
- Solicitation number
- S-C01010-00001929
- Issued by
- Clackamas County, Oregon
About this file
This document is a response to clarifying questions submitted by interested firms for Invitation to Bid #2022-12 for the Barton Park Day Use Well Project, which is a contract opportunity issued by Clackamas County and Oregon City. The bid solicitation requests services to install a new well and booster pump system to provide water to reservoirs serving the East Campground and Day-Use area of Barton Park. Key details include that the well pump should be placed at least 10 feet above the bottom of the well, and that the well is expected to produce over 80 gallons per minute, which would be sufficient to supply the 21,250 gallons of storage capacity for approximately 5.5 hours of sustained usage. The documents indicate flexibility in the well placement within the project area, and that a pre-construction meeting will be scheduled once a vendor is selected.
The documents provide clarification on the project scope, including that the booster pump will need to be replaced to accommodate the new well pump, and that the existing water lines running to the East Campground will need to be connected to the new booster pump system. There are also details provided on potential changes to the well design based on encountered ground conditions, with the option for the vendor to bid an 8-inch diameter well and provide a credit for reducing to a 6-inch diameter in the lower section if needed.
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Text version
INVITATION TO BID #2022-12
Barton Park Day Use Well Project (“BID”)
RESPONSE TO CLARIFYING QUESTIONS#3
March 3, 2022
Note that these are questions submitted by interested firms to the above referenced solicitation.
The below answers are for clarification purposes only and in no way alter or amend the BID as published.
1. An answer to the question of the booster pump. With the size of the anticipated submersible pump, the current booster pump would not be capable and would need replaced.
Answer: We will work with the selected vendor on properly sizing the booster pump for the system.
2. What is the preferred depth for the pump to be set at?
Answer: The well pump should be placed at a depth within the well to produce the minimum required flow, but no less than 10’ above the bottom of the well.
3. For trying to properly size the pump, what is the estimated length of time for the sustained usage rate of 80GPM? Based on surrounding wells, this well should produce well over 80GPM, and if the refresh rate of the well hold up it could be indefinitely. But if the well refreshes slower, it could sustain 80GPM for 15 minutes, or 15 hours, or 15 Days. This will also determine the depth of the pump relevant to the storage capacity of the well design. hat is the connection size, type and material type to connect to the booster pump system?
Answer: The well pump will supply 3 reservoirs totaling 21,250 gallons capacity, so 5.5 hours sustained usage should be sufficient.
4. Will site security fencing be required?
Answer: We do not require security fencing for the site. However, the work site is in a public park, and cordoning off the work area for safety during construction will be vendor’s responsibility.
5. Will there be a pre-construction conference?
Answer: There was no mandatory pre-bid walkthrough, but bidders have the option of requesting a site visit. Once a vendor is selected, a pre-construction meeting for vendor and park staff will be scheduled.
6. The package states connect to booster pump, and connect to water lines running to east campground? Is that the same system connected to the booster pump or are there separate lines running from the well? These lines not appear to be shown on the drawing.
Answer: Yes, the booster pump feeds the lines to the East Campground. Those lines currently exist and run to the well shed, and will need to be fed by booster pump in the new system. The stub out to the Day-Use area is new, and park staff will connect it to the new water lines they are running in the area. The Day-Use area waterlines are to be fed from the pressure tanks vendor will install in the well shed.
7. Can the well be drilled anywhere in the general zone shown on the “Park Overview Map?”
Answer: No. There are areas like a seasonal creek bed, the access road, and a footbridge within the ‘project area’ that would need to be avoided. But there is flexibility within the project area for specific placement. There is an open area within 50’ of the well shed that seems like the most logical place for a wellhead. Park staff will work with selected vendor on specific placement.
8. Clarification on well construction design. Once we know what the desired 80 Gallon Per Minute sustained rate, we can better design the well and pump combination. In the well drilling industry, the actual well performance and intended use determines the sizes and depth of the pump. Normally, the well is drilled, then the pump is sized to meet the needs of the customer. In this case, we are taking a lot of assumptions in pre sizing the well. We are basing the design on 760’ total well depth, with water bearing zone to be between 683’ and 760’. Without knowing the refresh rate of the well, we are anticipating setting the pump near the bottom of the well. If the well produces a lot of water, the pump can be set higher at a substantial saving in material.
Answer: We look to our vendors expertise on the best way to make the system produce the desired results.
9. As for construction of the well, we will not be able to drill the well without the flexibility to change diameter size near the bottom. If the ground cooperates, we will be able to drill down to 760’ and install an 8” casing. If the ground conditions change and there is unconsolidated material, the drilling will stop due to the size of the hole. Industry standard is to go down to a 6” casing to finish out the well. We understand there is a storage capacity change in the lower section of the well with a diameter change. But the well logs of the surrounding well are indicating the water yield should be well above what is needed to sustain the water usage by the pump even with the lower storage volume.
Answer: We understand that ground conditions may dictate changes to design. You may specify a bid for 8” diameter all the way down, and then clarify what credit will be given to the owner if the last section of pipe needs to be reduced to 6” diameter.
End of Clarifying Questions#3
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