The South Sound is one of the fastest growing areas in the state, exceeding the State’s growth rate consistently since the 1960s. Much of the population centers on towns and cities of Shelton, Olympia, Lacey, Tumwater, Steilacoom, University Place, Lakewood, Tacoma, and DuPont, the community of Allyn, and along shorelines of the finger inlets and islands. Forest and freshwater habitats have been and continue to be impacted by varying land uses such as urban, rural and mixed use developments, commercial forestry, and tribal and non-tribal commercial shellfish industries. The loss of forest cover and degradation of freshwater habitats (such as rivers and streams) negatively affects the South Sound’s natural ability to deliver watershed functions that support freshwater systems, provide habitat for terrestrial species, and provide ecological and cultural services for humans.
Forest Cover: Large and small patches of forest and shrub vegetation occur throughout the South Sound with Harstine Island supporting the greatest proportion of forest cover (93%). The Key Peninsula and upper reaches of the Nisqually watershed also have some of the highest forest cover in the South Sound. The Deschutes unit experienced the greatest reduction in forest cover (-5%) and the Harstine Island and Totten & Little Skookum Inlet groups experienced the least (-0.8%). The Henderson Inlet AU experienced the greatest increase in developed land cover (+4.1%) and the Budd and Case Inlet groups experienced the least (both at +0.2%).
Freshwater Riparian Vegetation: Overall, the major streams in the South Sound have an average of 61% intact riparian cover. The major streams with most degraded riparian habitat cover include Sequalitchew Creek and waterbodies in the Chambers-Clover watershed.
Freshwater Flows in Rivers and Streams: As reported in 2015 State of the Sound Vital Signs, summer low flows in the Nisqually River show a strongly increasing trend over the current period of record (1975-2014) and low flows in the Deschutes River are weakly decreasing.
Fish Passable Streams: South Sound has 361 total fish passage barriers, and 521 partial barriers. The Totten & Little Skookum Inlet Group has the highest concentration of total barriers (55) followed by the Hammersley Inlet & Oakland Bay Group (51). Harstine Island has the fewest total blockages (7), although this mostly due to the low number of freshwater streams on the island.