Sequalitchew Creek has undergone a series of alterations in the last 100 years from urban, military and private industry development. Construction of the BNSF railway occurred circa 1915, effectively reducing fish access and impounding tidal exchange processes between the estuary and shoreline. The diversion dam at the outlet of the Sequalitchew Lake has reduced creek flows by 50 cubic feet per second (cfs), leaving low summer flows at an average of 1.4 cfs.

Sequalitchew Creek's estuary has been impacted by development, but still retains some habitat function. The estuary's size has been significantly decreased from historic conditions by the installation of the Burlington Northern-Santa Fe railroad causeway (Figure 2.). An undersized box culvert passes tidewater and, to some degree, fish. High water velocities during tide exchanges may present a partial fish passage barrier. With adequate fish passage and tidal exchange, the estuary would serve as excellent rearing habitat for juvenile salmonids migrating along the shoreline.

The creek delta supports a relatively large eelgrass bed , an important habitat for rearing and foraging juvenile salmonids. Seine studies conducted by the Nisqually Tribe and the South Sound Salmon Enhancement Group have documented use of the Sequalitchew Creek shoreline by Chinook, chum, coho, cutthroat, sculpin, 3-spine stickleback, gunnels, surf perch, shiner perch, pacific herring, and surf smelt. Surf smelt and sand lance spawning has been documented just south of the creek outlet.

Sequalitchew Creek Estuary offers a suite of restoration opportunities, that when compared to some other systems can be very low cost yet very effective at restoring a relatively healthy urban stream.
1. The undersized culvert under the BNSF railline at the mouth of the estuary should be replaced with a larger structure, ideally a trestle that spans the historic mouth of the
2. Low flow issues can initially be addressed by removing the diversion structures and blocking the diversion canal, forcing water back into Sequalitchew Creek. Discussions surrounding the status of the diversion dam at the outlet of Sequalitchew Creek have been initiated with Fort Lewis.
3. Years of low water and neglect have led to a proliferation of invasive plant species that need to be removed through a series of organized citizen volunteer work parties.
4. The beach around the mouth of estuary could be restored through removal of derlict, creosote structure and softening of the shoreline.