B08_Attachment_1_SOW_OSU_Skilak_ROV.docx

STATEMENT OF WORK

The U.S. Geological Survey (USGS) has a requirement for remotely operated underwater vehicle (ROV) services to support recovery of an ocean-bottom seismograph (OBS) from ~200 m water depth in Skilak Lake, Alaska. The planned work period is between August 25 and September 8, 2025.

USGS deployed two broadband OBS in Skilak Lake in May 2024 and attempted to recover both instruments in June 2025. These OBS are typically recovered by sending an acoustic command that triggers release of a 175 lbs (air weight) steel plate anchor. Once the anchor is released, the instrument has ~65 lbs of buoyancy and floats to the surface for recovery by a surface vessel. The OBS weighs 530 lbs (air weight) without the anchor and measures approximately 4’ x 6’ x 3’.

One OBS was successfully recovered in June 2025 using the acoustic release. The second OBS communicated acoustically but did not surface after triggering the release. As of June 2025, the instrument was replying to acoustic commands. Based on the extremely muddy condition of the recovered OBS, the remaining instrument is assumed to be stuck in glaciolacustrine sediments. The goal of this work is to use an ROV to: (1) visually inspect the current condition of the OBS and (2) attach a recovery line to the OBS that can be pulled from a surface vessel. The OBS sits in 200 m water depth at a location known to within ~10 m.

The work will require three (3) onsite workdays, plus two (2) days for mobilization and demobilization. Mobilization and demobilization will occur at the USGS Earthquake Hazard Program’s warehouse space in Anchorage, Alaska. Mobilization and travel to Skilak Lake will take one day. Demobilization and return travel from Skilak Lake to Anchorage will also take one day.

The actual ROV operations are expected to take one day. Two days extra workdays are included for weather and technical contingency. If the contingency time is not needed for the OBS recovery, USGS reserves the option to use the extra time for video inspection of geologic features using the ROV.

The ROV will be operated from the USGS’s R/V Lutris, a 25-foot Boston Whaler based at Alaska Science Center. USGS will be responsible for vessel and OBS operations and transportation. Due to remoteness of the worksite, USGS personnel and ROV operators will camp at the U.S. Fish and Wildlife Service’s Upper Skilak Lake Campground during the onsite work period. USGS will be provide transportation for personnel and equipment to and from Skilak Lake.

This work is being done as part of the USGS Subduction Zone Marine Geohazards Project and in collaboration with scientists at the USGS Coastal and Marine Hazards and Resources and Earthquake Hazards Programs.

Specifications to be provided to USGS

1. Detailed technical specifications of ROV, including attached instrumentation (power supply, sonars, etc).

2. Description of relevant experience of the ROV and operators including a list of successful recoveries of oceanographic equipment using the ROV proposed for this work.

Requirements

1. ROV: Vendor to provide an ROV with the following capabilities:

a. must be able to work in up to 250 m water depth;

b. must be hand deployable and recoverable from a small surface vessel (25’ Boston Whaler);

c. must be able to operate for at least 12 hours using power supplied from the surface vessel. (USGS will supply a 2000 Watt or greater generator on the surface vessel);

d. must have a video feed viewable in real-time from the surface vessel;

e. must have a multibeam imaging sonar with real-time feed to surface vessel that is capable of locating instrumentation on the lakebed in ultra-low visibility conditions; and

f. must be able to attach a recovery line between the OBS and the surface vessel. The recovery line must have a working load limit (WLL) of 5000 lbs or greater and will be used to pull the OBS from the surface vessel. (If necessary, a smaller sized “messenger line” can be used to make the initial attachment if a 5000 lbs WLL or larger line can eventually be connected.)

2. Delivery: Must be able to deploy as soon as August 28, 2025 and include confirmation of this in your quote.

3. Operators: Vendor to provide two experienced ROV operators with a record of recovering large seafloor oceanographic instrumentation using the ROV specified above.

4. Transportation: Vendor is responsible for airfare for operators and equipment shipping to and from Anchorage, Alaska. USGS will provide ground transportation to/from Anchorage to Skilak Lake. USGS will supply and operate surface vessel on Skilak Lake. USGS will handle OBS handling and transportation.

5. Lodging: Vendor to provide lodging for operators in Anchorage on mobilization and demobilization days. All personnel will camp at Skilak Lake during the work period. USGS will cover the campsite fee and make available kitchen equipment and tents. ROV operators to provide all personal equipment (sleeping pads, sleeping bags, rain gear, etc.).

6. Meals: ROV operators are responsible for their own meals. If desired, meals and food can be coordinated with USGS personnel, but ROV operators are responsible for their portion of the food costs.