Amendment_1_-_QAs_0001.docx

Solicitation 140P1423Q0002 – Septic Pumping for Yellowstone National Park 1 December 2022 Q&As Septic Tank Operations and Setup

1. What are the size and dimensions of the tank?

· The 50,000-gallon septic tank is 64’ long, 12’ wide, and 12’ to 16’ deep. It is divided into 2 sludge chambers (each with 2 hoppers in the bottom) and one effluent chamber at its downstream end.

2. What are the manholes and vaults along the east side of the tank?

· The vaults on the east side of the tank contain valves that were used when this tank was operating regularly from the 1930s – 1960s. These are not part of the current operation so will not be involved with the septic pumping.

3. Is flow currently going into the septic tank and will this continue throughout the duration of the contract?

· Yes, wastewater flow from all of Mammoth is currently flowing through this septic tank. Prior to June 2022, all wastewater from Mammoth flowed by gravity to Gardiner, MT, where it was treated at the Gardiner Wastewater Treatment Plant. During flooding in June 2022, several sections of the gravity line completely washed out. At that time, the park switched Mammoth’s wastewater flows to an old treatment system that was used from the 1930s to 1960s. The old system directs flow through the septic tank and out to infiltration ditches and ponds. The park will continue using this system this winter as long as weather allows. A temporary treatment plant and new unlined percolation ponds are in the process of being constructed. Once the existing system freezes, flows will be pumped from the septic tank up to the new ponds, or through the new plant and to the new ponds, depending on construction progress.

4. How was the tank used prior to June 2022? Was it pumped regularly?

· After wastewater flows were directed to Gardiner in the late 1970s, the septic tank was used as an overflow tank for the adjacent lift station, which served the Lower Mammoth housing area. As an overflow tank, it did not have regular flows. During that time, the park pumped out the tank as needed.

Pumping Logistics

5. What solids are anticipated to be in the tank when it is first pumped?

· During the site visit, we observed a significant crust layer (approximately 1 foot deep in the upstream end of the tank) but it decreased throughout the length of the tank. A measurement in mid-October indicated approximately 4.5 feet of settled sludge at the bottom of the tank. Solids will continue to build up until the first pumping event.

6. Where will the pumper truck be dumping?

· The pumper truck will dump into a manhole not far inside the park entrance, along the old North Entrance Road. The contractor will likely use a manhole approximately 0.2 miles from the gate.

7. Will the contractor pump from lagoons or just the septic tank?

· If the park shifts from using the old, existing ponds to the new ponds, it is possible that the contractor would need to pump from the new ponds at some point.

8. Could the initial pumping load, with a high concentration of solids, be dumped at the Gardiner Wastewater Treatment Plant instead of in a manhole? This could help avoid the solids settling in or downstream of the manhole and clogging the collection system.

· Dumping the first load or loads directly at the Gardiner Wastewater Treatment Plant (WWTP) may be possible but is not guaranteed. The National Park Service will discuss this possibility with the Gardiner Water & Sewer District and provide further direction. The Gardiner WWTP is located just downhill of the Gardiner Airport.

9. Will someone from the National Park Service (NPS) be onsite during pumping operations?

· The NPS does not anticipate being onsite during all pumping operations. However, NPS will have staff onsite as needed when possible.

10. The SOW mentions that “The septic tank and sewage ponds are located in an active construction zone. Contractor shall plan to coordinate with construction contractor as needed for access”. Does this mean there are certain days and times when pumping cannot occur?

· There are no known days or times when the contractor will not be able to pump. The ongoing construction was noted in the SOW because the access road where the pumper truck will park to pump the septic tank is also used by the construction contractor and some construction work will occur near the south end of the septic tank. The construction contractor will have some occasions when oversized loads will be entering or leaving the job site. The pumping contractor and the construction contractor should communicate to minimize conflicts between their operations.

11. What’s the steep and grade of the roads?

· Steepest Grade is at 12%-14% with a few 10% grades too.

12. Does the vehicle used have to be a straight vehicle, or can it be a semi-truck / trailer?

· Semi -Truck travel is possible but given the current winter conditions it is not advisable. Pumping location is off road and dumping location is located in a lesser maintained roadway. Chains will be required on all snow-covered roads inside Yellowstone for towing vehicles.

Park Access and Lodging

13. Will the contractor have to pay to enter the park?

· No, the contractor will be issued gate passes. These passes must be presented at the entrance gate and will allow the contractor to enter the park for free for contract-related work.

14. Is park housing available?

· The park can provide 2 housing units in Gardiner for the contractor to use.

15. Is there an indoor location where the contractor can store their pumper truck?

· There is not an indoor location for the contractor to park their truck. An outdoor plug-in location may possibly be available for the contractor.

Contract Questions

16. Will this be awarded to just one contractor?

· We currently anticipate awarding one contract for this work.

17. When does the park anticipate pumping starting?

· The start date will be approximately middle of December 2022 to early January 2023.