Over one hundred projects have been funded through the authority and strategy that include the removal of man-made obstacles that prevented fish migration, provided plantings of trees and shrubbery around creeks and tributaries that help increase biomass while lowering water temperatures, and purchasing of land near watersheds for permanent protection.
With a wide agreement on protecting local ecosystems, especially salmon habitat, migration routes, and spawning areas, competing proposals of various support and opposition have been introduced in the 21st century to solve the ongoing mission to mitigate flooding in the Chehalis River basin.
Competing proposals, offered by tribal communities and citizen groups in the region, rely on natural corrections to the floodplain, including heavy biome restoration in the basin as well as the prevention of future construction in the watershed.
With the introduction of railroads in the 1870s, and a subsequent increase in timber harvesting due to the new rail systems, denuded forest land around the Chehalis River led flood waters to be mostly contained in deeper valleys and channels.
[4] A comprehensive study, known as the Programmatic Environmental Impact Statement, was released by the Department of Ecology in September 2016 and detailed four options, titled "Alternatives", on flood control and the creation, protection, and restoration of aquatic habitats in the Chehalis River basin.
Though the report agreed with long-standing ideas and proposals of local flood mitigation and ecosystem protections, the introduced options were also based on financial and timelines costs, as well as funding and community willingness.
[11][12] In late 2024, the OCB requested a $80 million budget appropriation from the state legislature that is to fund the authority and basin strategy until 2027, helping to "aggressively pursue" various continuing projects, including the advancement to build a pass-through dam.
As of 2024[update], the OCB, authority, basin strategy, and connected participants have completed 140 ecosystem restorations, which includes over 300 acres (120 ha) of preservation, and provided flood protection for more than 200 residences and commercial buildings.
[21] Log jacks were installed in Montesano that helped increase the riverbank of the migrating Wynoochee River, which was threatening the local wastewater plant that, during flooding, would have inundated the community with sewage runoff.
[22] An aging and failing pump installed during World War II at the Chehalis–Centralia Airport was replaced in 2018 with a redundant dual-pump electric system, protecting the airfield and the local shopping district.
[26] Additional ASRP restoration projects include fish passages in Elma and Oakville, and habitat improvements to creeks and their watersheds within Lewis County and the city of Chehalis.
[18] Beginning in 2012, Grays Harbor County underwent several projects, mostly upgrades or construction of floodwalls, levees, and pump houses, to protect flood-prone communities in the region.
The county struggles with high waters after excessive rainfall due to flat topography, the drainage of the Chehalis River watershed into the Pacific Ocean, tidal surges, and coastal flooding.
Plans included the elimination of excess erosion with logjam jacks, the reintroduction of 350 acres (140 ha) of riparian habitats, improving the ecosystem for salmon and other aquatic species, and helping mitigate flood concerns in the area.
[31] Part of the basin strategy is to remove artificial barriers and to restore forests and woodlands near the Chehalis River and its tributaries, to promote the habitats of aquatic species such as salmon, steelhead, and trout.
As of 2023[update], the project, led by the ASRP, has worked with an ongoing WDFW program begun in 2005 that has removed or reengineered 81 man-made impediments in the Chehalis basin at a cost of $27.6 million.
[3] Studies of the build of the dam has been determined it to be of positive economic value to the region as major flooding events would be significantly reduced while protecting infrastructure and various populated areas.
[37] The flood retention project has also shown to likely produce negative returns, such as disturbances to aquatic habitat, water quality of the Chehalis River, as well as adverse affects on recreation and Native American lands and culture.
The dam is predicted to provide little downstream benefit to communities in Grays Harbor County and only moderate reduction of flood waters to the lands of the Confederated Tribes of the Chehalis Reservation.
[2] The Quinault Indian Nation expressed concerns over the loss of fish ecosystems, specifically spring and fall Chinook salmon, a cultural staple of the indigenous people.
The revised dam incorporated several design changes due to a variety of concerns from prior studies and protests, such as protection of aquatic and vegetative habitats, recreation access to the river, and potential disruption to Pe Ell's water supply..[40][41] After the discovery of the Oregon spotted frog in the watershed of the Black River in Thurston County, Washington, a species thought to be extinct in the area, a cooperation between the non-profit Capitol Land Trust and a landowner purchased 60 acres (24 ha) around the Blooms Ditch tributary in order to establish a habitat for the amphibian.