Hood Canal is in Washington and connects to Puget Sound. Anthropogenic water and noise pollution from industry are problems. Kip Taylor from Parkland, a former major in the Marines who for three decades has seen this. Richard (Rick) Hicks from Seattle, a multi-disciplined freelancer and University of Washington graduate advertised on Craigslist.org for CAD and GIS services, and Mr. Taylor answered the ad and we got together to design a fish ladder for use in the canal. For the pollution issue, and oxygenation tunnel for low dissolved oxygen (DO) areas from Puget Sound to Hood Canal the designs were put into CAD drawings documented for mapping placement. See the bottom of the page for drawings. View or download the Sea Grant detailed article on the problem below.
To support increased oxygen to acceptable levels for fish (from about 1 mg/L Hood Canal and about 6 mg/L Puget Sound) where a concentration of 5 mg/L DO is needed for optimum fish health, however, sensitivity to low levels of dissolved oxygen is species-specific. Most species of fish are distressed when DO falls to about 3 mg/L and mortality usually occurs at concentrations less than 2 mg/L according to internet sources.
One approach is to add an oxygenation/aeration tunnel from Puget Sound to Hood Canal underground to Case Inlet/North Bay (fig. 3, 4 & 5). Alternate configurations are possible with the figures and links below. A major concern is keeping the water passage free from debris including silt and sand with no way to know without scaled testing.
The tunnel addition for O2 level increase is not quantifiable at this stage of development.
Another concept from Kip is an innovation in fish ladder design (fig 1). Stacks of these ladders are needed for fish to climb and to get to the spillways or the top of dams.
Lake Cushman Dam & Lake Kokanee Dam (a.k.a. Cushman 1 & 2) are potential locations however, no readable/usable engineering drawings from the survey gallery are available online:(https://www.loc.gov/resource/hhh.wa0270.photos/?sp=1&st=gallery).
Prior to Kip Taylor passing away, the concept was different using a single venturi nozzle at the outlet. Those passive-plan drawings were kept and drawing scans are available from the links below. Thoughts were the venturi system to have a bubblator-type (venturisysdetails download below) to add air, or air pump(s) to increase O2.