by Richard Uhlhorn
When an expensive item is lost overboard in deep water, the chances of recovery diminish based on a number of factors; location, bottom conditions, currents, sediments and the equipment used to search and recover.
On May 11 the Lake Chelan Research Institute was conducting a lake quality monitoring operation when its $15,000 multiparameter probe separated due to an undetected line defect. The probe ended up in 400+ feet of water between State Park and Willow Point Park.
The location was noted on GPS so recovery efforts could take place close, and hopefully, in the vicinity of where the 11 pound probe ended up on the bottom.
Recovery efforts have included dragging the bottom to no avail. Dr. Phil Long was interested in utilizing an underwater ROV (remotely operated vehicle) to add in the recovery of the instrument array. Long began researching rentals and other potential options to get an ROV on the lake.
He got the help he needed from Aaron Burnett, an outreach specialist with the Washington Sea Grant program at the UW. Burnett had Long call Celina Ladyga, Lt. Commander in charge of Maritime Safety & Security Team in Seattle.
Ladyga approved sending two ROV technicians to Chelan with an Underwater ROV. On Monday morning, August 2, the Coast Guard technicians; Alaric Grecius and Tedd Meinersmeen met Long, Tim Sullivan and Ian Blevins, a Manson High School graduate with an interest in ROVs.
Shaun Sherman and I were in his boat with the job of keeping vacationing boaters away from the work area.
Even on the lake, the day was blistering hot. When the GPS location of where the instrument was lost was reached, Sullivan, a retired Coast Guardsman, set up his trolling motor with an anchor lock to keep the boat on the GPS coordinates.
Grecius and Meinersimenn ran their first dive, taking sonar readings in hopes of locating the array. This didn’t work, so they brought the ROV back to the surface to attach its grappling arm and submerge once more to conduct a much broader back and fourth search pattern.
Unfortunately, as so often happens on operations involving underwater work, a software glitch cropped up and the operation was suspended until the next day.
On Tuesday morning, with the glitch fixed, the ROV was placed on the bottom of Lake Chelan and the Coast Guard technicians conducted a search pattern over the bottom in hopes of finding the scientific array or the 400 feet of cable that broke and sent the $15,000 package to a watery grave… at this point. Despite the search pattern, it is like hunting for a needle in a haystack.
Since the ROV’s side and front scanning sonar doesn’t penetrate the sediment. the hunt was called off.
Joe Heinlen, a local fishing guide and boat operator for the Institute is going to re-rig a dragging system and try to hook the array that way in the near future.
In light of all the recovery efforts, Dr. Long told Chelan City Council that the monitoring probe was reaching its five year life span, so replacement of the probe was high on the Institute’s list of needs.
The Institute, which had a $2,000 replacement fund and had already raised $5,300.00 towards the probe’s replacement from private donations and Chelan County PUD, Long requested financial help in replacing the probe. He asked the Council to approve financial assistance of $6,460.10.
Long told the Council that oxygen levels are the same as from 1987 and 1998. We know that year after year the lake is stable over time,” said Long. “Now we are losing 2021.”
Long added that one of the bigger concerns is the algae growth near shore. “There are more boats on the lake and we need to educate people to fertilizer their lawns a lot less.”
Peter Jamtgaard asked Long what would prevent losing a new probe in the future. Long explained that the new line they were using on the probe didn’t have a safety core in it and they didn’t know that. He said the Institute would be using a 1000 lb. test safety line to make sure it doesn’t happen again.
“Your track record shows good stewardship of City and County money,” said Time Hollingsworth. “It is essential that we collect that data. I move to approve the $6,460.00.
The Council unanimously approved the expenditure and Long has ordered a new probe and is still in hopes that old probe can still be recovered.
Other issues facing lake quality are listed by the Institute in no particular order:
- Leaking septic systems uplake from Minneapolis Beach on the South Shore;
- Waterfowl feces (ducks, geese and seagulls);
- Agricultural drains and creeks that drain agricultural lands, particularly in the Manson Agricultural area;
- Over fertilization of lawns and orchards near the lake even if no ag drains exist.
- Atmospheric deposition including wind blown dust from construction sites and ash from wildfires;
- Re-suspension and erosion of sediments by wave action;
- Decomposition of near shore aquatic plants;
- Internal loading from bottom sediments; and
- Runoff from drainages with recent wildfires.