Ecology in the Mid-Coast Region

Ecology Snapshot

The ecology in the Mid-Coast was summarized in a report as part of Step 2 of the planning process and can be summarized as follows:
 

  • The Mid-Coast supports a variety of habitats, with aquatic habitats being of particular interest because of their connection to human population water supply needs. Aquatic habitats include streams and springs, lakes, riparian areas, wetlands, and estuaries.
     

  • The Oregon Conservation Strategy identifies species of interest and areas of ecological importance in the different regions of the state. The OCS identified 12 streams or estuary habitats as areas of ecological importance in the Mid-Coast because of the diverse habitats and species they support. For example, the Siletz Watershed has the only coastal origin population of summer steelhead in Oregon.
     

  • Aquatic species of interest in the Mid-Coast include seven species of salmon, green and white sturgeon, beaver, and three species of lamprey. The seven salmonids are: coho, chum, fall chinook, spring chinook, winter steelhead, summer steelhead, and sea-run cutthroat. Oregon coast coho salmon is listed as threatened under the Endangered Species Act and large portions of the Mid-Coast are designated as critical habitat for coho. Green sturgeon also is listed as threatened within the Southern Distinct Population Segment, which includes Yaquina Bay.

  • Salmon are a keystone species in the Mid-Coast because of their influence on other plant and animal species. Salmon are an indicator species for habitat health because they require diverse quality habitats throughout their lifecycle that other species also require.
     

  • Sources of habitat degradation include: stream channel simplification and incision, warm stream temperatures, altered streamflow timing and watershed function, turbidity related to peak streamflow, and toxic and non-toxic pollutants.
     

  • Aquatic habitat restoration efforts occur in the Mid-Coast to increase stream channel complexity, reduce fine sediment inputs and summer water temperature, address fish passage barriers, and encourage  beaver dams, or similar structures.

Habitats in the Mid-Coast

 

Aquatic habitats include rivers, streams, springs, riparian areas (i.e., interface between water and land), estuaries, wetlands, and lakes. The shape of each river basin (how confined the river valley is, the type of bedrock geology, the gradient or slope of the stream, and the local climate) determines the types of streams that occur in a basin. 

 

Good quality habitat in streams includes quality water - cool temperatures, high dissolved oxygen, and low turbidity. Temperature affects water chemistry and species survival. Healthy streams are able to maintain summer temperatures below levels that are unhealthy for the species of interest. Shade, groundwater and subsurface flow, and overall streamflow (i.e., water quantity) moderate temperature. Streams are more vulnerable to warming when riparian areas do not provide enough shade, most or all of the streamflow is on the surface (i.e., the stream is running over bedrock), and streamflow decreases. Temperature and dissolved oxygen concentration are linked, and both parameters are critical to the reproduction and survival of anadromous fish.

Riparian habitats are the upland areas immediately adjacent to streams. Healthy riparian habitats have woody plants that stabilize banks, contribute large woody debris, contribute food supply for instream species, and provide shade that reduces stream temperature fluctuations. 

At the interface between freshwater and saltwater are estuary habitats, which support diverse plant and animal species. Estuary habitats provide an important freshwater-saltwater transition area for salmon. The Mid-Coast has two types of estuaries:
 

  • Drowned river mouth estuaries are river valleys that flooded about 10,000 years ago from sea level rise.
     

  • Tidally restricted coastal creek estuaries are streams that discharge directly into the ocean and experience inputs of ocean water during high tides.
     

The main types of wetlands in the Mid-Coast are: aquatic beds, marshes, peatlands, wet prairies, scrub swamps, and forested swamps.

The largest lakes in the Mid-Coast are Devil’s Lake (a natural lake located near Lincoln City), Valsetz Lake (formed by Valsetz Dam on the South Fork Siletz River) Olalla Reservoir (formed by Olalla Dam on Olalla Creek), and Newport Reservoir (formed by Big Creek Dam on Big Creek). 

A submerged log at Devil's Lake.

Beaver on the Oregon coast.

Species and Habitat Needs

 

The Mid-Coast has many species of interest that spend at least part of their life cycle in water and are listed by state or federal agencies for protection or monitoring and/or identified by the Oregon Conservation Strategy (OCS) as a “species of interest.” Species of salmon in Mid-Coast watersheds include: coho, chum, fall chinook, spring chinook, winter steelhead, summer steelhead, and sea-run cutthroat Trout. Salmonids require large woody debris, deep pools, and spawning gravels. Factors negatively impacting salmonids are low water availability (particularly in late summer and fall), impaired water quality (e.g., warm stream temperatures), and fish passage barriers (e.g., undersized culverts). Green and white sturgeon are also species of interest in the Mid-Coast. Sturgeon are especially sensitive to estuary conditions, where they congregate during summer and fall. Sturgeon spawn in freshwater several times during their adult life, thus adults and juveniles are also sensitive to freshwater conditions, including stream temperature and gravel conditions.

Several species of lamprey (Pacific, River, and Brook) are also species of interest and require many of the same habitat characteristics as salmonids.

 

Beavers are yet another species of interest because of their ability to build dams and create ponds that provide habitat for other wildlife, promote nutrient cycling, moderate flows, and recharge the aquifer, among other benefits.

 

Other species of interest are invasive species, which are non-native species that have a disproportionate effect on the ecosystem that is typically negative, such as outcompeting and displacing native species and reducing species diversity.

Regulations Affecting Species and Habitats

 

The Mid-Coast is about 96.5% forested. Most urban development occurs along the coast and rural development along the valley floors of major rivers . The coastal areas of the Mid-Coast have multiple land uses, including urban areas, commercial areas, and residential areas. The Yaquina Bay area in the City of Newport is the most developed estuary in the Mid-Coast. Lowland areas along the Salmon, Siletz, Yaquina, Alsea, and Yachats Rivers also have multiple land uses, including rural residential development and farming. About half of the forested areas are privately owned, the majority of which is managed as industrial forestland. Public forestlands in the Mid-Coast are owned by the U.S. Forest Service (USFS), U.S. Bureau of Land Management, and Oregon Department of Forestry. The Confederated Tribe of Siletz Indians owns forest land in the middle portion of the Siletz Watershed.

OR Statewide Planning Goals and Guidelines

The Land Conservation Development Commission specifies the level of development allowed to occur within the state's estuaries, and requires inventories on the physical, biological, social, and economic resources of each estuary.

Endangered Species Act

The Ac protects and recovers imperiled species and the ecosystems upon which they depend. A list of Oregon's endangered species can be found here.

Oregon's Sensitive Species Rule

The Rule provides for the protection of species at the state level Sensitive species have small, or declining, populations, are at-risk, and/or are of management concern.

Aquatic Habitats

 

Streams

Healthy stream habitats have cool temperatures, high dissolved oxygen, low turbidity, riparian vegetation, and stream channel complexity. Stream health benefits from watersheds that store precipitation in springs, wetlands, beaver ponds, and in the streambanks/floodplains. In healthy streams, streamflow often overtops streambanks during flood events. When this occurs, floodwaters are slowed by streamside vegetation, providing refuge for aquatic species from high flows. Finer sediments, larger cobble, and boulders suspended in floodwaters are deposited in floodplains and store water that is later released into the stream channel. Stream health also benefits from a diversity of disturbances in the watershed, such as fire, debris slides, wind storms, and floods that increase habitat diversity. Floods move large substrate and large woody debris from upper reaches and tributaries to lower reaches within the watershed.steep- walled canyons more large wood comes from upslope areas. 

Stream temperature affects water chemistry and species survival. Shade, cool groundwater discharges into the stream, and water quantity moderate stream temperatures. Temperature and dissolved oxygen concentration are linked, and both parameters are critical to the reproduction and survival of anadromous fish. Stream temperature affects biological triggers for salmon migration, spawning, and egg hatching. High stream temperatures and low dissolved oxygen, as well as high turbidity can threaten fish survival at various life stages.

Riparian Habitats

Riparian habitat is at the interface between land and a river or stream. Plant and animal species may use all riparian habitats, or may specialize on a particular geomorphic surface within the riparian area. Rivers are constantly changing, eroding surfaces, and depositing material to create new surfaces. Similarly, vegetation communities in riparian areas change as they become inundated by flood waters, dried out because of a shift in the direction of streamflow, or fall into the stream channel from bank erosion. Upland and riparian habitat

influences instream health, and upstream health influences downstream characteristics.

Landscape-relationships-of-uplands-and-r

Graphic: Instream corridor restoration: Principles, Processes, and Practices, 10/98. Interagency Stream Restoration Working Group (FISRWG) (15 US federal agencies).

Estuary Habitats

Estuaries provide a transition zone between freshwater and saltwater, and contain unique habitats that support a diversity of plants and animals adapted to a balance of saltwater and freshwater. Estuaries also serve to filter pollutants, stabilize shorelines, and buffer communities from storm surges. Estuaries are especially important for salmon during key points in their lifecycle. Estuary habitats are influenced by watershed size, geology, ocean tides, and freshwater-saltwater mixing. Although estuaries are dynamic systems that change with high tide and low tide, they are also sensitive to changes. Plant and animal communities in each estuary are adapted to a specific range of salinity. Changes to sea level, ocean currents, or freshwater inputs from streamflow can alter the balance of saltwater and freshwater and sediment dynamics, impacting plant and animal communities.

 

  • For more information about different types of estuaries, click here
    and here.The Coastal Atlas Estuary Data Viewer can be accessed here.

  • For more information about individual estuary management plans, click here.

Graphic: US Army Corps of Engineers.

Mid-Coast estuaries, with the exception of the Depoe Bay Estuary (which is small), are moderate in size and have large areas of salt marsh, eelgrass, and tidal flat habitat. 

 

Salmon River Estuary

 

This is classified as a Natural Estuary and has little residential, commercial, and industrial development. The entire estuary and its associated wetlands are part of the Cascade Head Experimental Forest and Scenic Research Area, which is owned and managed by USFS. The entire Cascade Head area is 11,890 acres; the estuary comprises 205 acres.

 

Areas of Ecological Importance and Critical Habitat Designations: Habitat areas include wetlands, mudflats, emergent herbaceous wetlands, and intertidal marsh. The estuary provides transitional habitat between freshwater and saltwater for upstream spawning migrations for anadromous fish and rearing areas for juveniles and smolts.The Salmon River Estuary is part of the Salmon River Estuary-Cascade Head Conservation Opportunity Area.

 

Species of Interest: The Salmon River Estuary was nominated as an Important Bird Area for brown pelican, bald eagle, and peregrine falcon, and for its abundance of shorebirds, including western sandpipers.

Siletz Bay Estuary

Siletz Bay is classified as a Conservation Estuary. It lacks jetties or channels, but is near Lincoln City, which has altered some of the shoreline near the estuary. USFWS manages a 568-acre portion of the bay as a national wildlife refuge, which includes coastal conifer and hardwood forest, estuarine tidelands, and freshwater riparian habitats. The estuary was formerly was diked to drain land for raising dairy cows. USFWS is managing the refuge to allow the salt marsh to return to its natural state, where tides inundate the refuge twice daily. The Siletz Bay is a Conservation Opportunity Area.

 

Species of Interest: The Siletz Bay Wildlife Refuge provides nursery habitat for Coho and Chinook Salmon, Steelhead and Cutthroat Trout, and other anadromous species. Spring Chinook usually arrive to the refuge in May, and American shad arrive between late April to the end of May. The refuge is also home to red-tailed hawks, bald eagles, barn owls, red-shouldered hawks, ospreys, turkey vultures, merlins, and peregrine falcons as well as estuary-dependent birds, including great blue herons, great egrets, Virginia rails, eared grebes, brown pelicans, buffleheads, common mergansers, wood ducks, northern shovelers, American wigeon, green-winged teals, and double-crested cormorants. Mammals at the refuge include Roosevelt elk, black-tailed deer, harbor seals, mink, river otter, muskrat, and beaver. Siletz Bay has native, common eelgrass as well as exotic Zostera japonica, which was introduced with non-native oysters.

Depoe Bay Estuary


Depoe Bay estuary is about 25 acres. The estuary is landlocked, with the exception of the harbor entrance, which was developed to support fishing, tourism, lumber, and agriculture. The bay supports bald eagle nesting sites and black oystercatchers, among other species. Depoe Bay is a Conservation Opportunity Area.

Yaquina Bay Estuary

 

Yaquina Bay is a 4,300 acre estuary located in the City of Newport. It is classified as a Development Estuary. Current uses of Yaquina Bay include fishing and fish processing, logging, shipping, tourism, aquaculture, and agriculture. The estuary has been dredged and filled at several locations to support these uses and to allow for development. Oregon State Parks owns the Yaquina Bay State Recreation Site, a 32-acre parcel of land overlooking the mouth of Yaquina Bay. There are large cultivated shellfish operations in the Yaquina estuary. 

 

Areas of Ecological Importance and Critical Habitat Designations:

Yaquina Bay is listed as critical habitat for Green Sturgeon. Yaquina Bay State Recreation site is a spruce and pine forested bluff. Lower Yaquina Bay has little freshwater influence and is popular for shellfishing. The Wetlands Conservancy has identified high salt marsh, tidal Sitka spruce swamp, and non-tidal Sitka spruce swamp as the highest priorities for habitat restoration. The estuary also has eelgrass beds, and nesting eagles and osprey. Spruce swamps are located in the upper estuary along Elk Creek and Little Elk Creek and areas for potential restoration of high salt marsh are located in Boone Slough and Nute Slough. Currently, there is an eelgrass mitigation project in the eastern portion of Marina Bed. Yaquina Bay is a Conservation Opportunity Area.

 

Alsea Bay Estuary

Alsea Bay is designated as a Conservation Estuary, is one of only four estuaries in Oregon that is managed for conservation under the CZMA, and does not have jetties at the ocean entrance. Recreational fishing and clamming is allowed in Alsea Bay and species present include cockles and purple varnish clams, softshell clams, and Dungeness crabs. There are two public boat launches at Alsea Bay, including the Port of Alsea boat launch and McKinley’s Marina.

 

Species of Interest: Alsea Bay supports Green Sturgeon as well as a diversity of other species.

 

Areas of Ecological Importance and Critical Habitat Designations: The east side of Alsea Bay has more than 400 acres of undisturbed marsh habitat and additional marsh habitat in the lower reaches of Drift Creek, a FEMAT-designated key watershed. Additional tidal high marsh habitat that is recovering from previous grazing disturbance is found west of Barclay Meadows and east of Eckman Lake. The Bayview Oxbow has about 150 acres of diked former tidal marsh. Barclay meadows contains small areas of diked former tidal marsh. Bain Slough is a forested wetland located at River Mile 9 that has well-developed remnant tidal channels. A tidegate, ditching, and residential development all reduce tidal influences at Bain Slough, which was likely a spruce tidal swamp at one time. Alsea Bay has been identified as a Conservation Opportunity Area.

 

Yachats River Estuary

Yachats River Estuary is about 40 acres and is classified as a Conservation Estuary. The Yachats River Estuary is part of the Yachats River Area Conservation Opportunity Area. It is a designated Important Bird Area of Oregon and includes marbled murrelet and spotted owl nesting sites.

Wetland Habitats

Wetlands are areas where water covers the soil, or is present either at or near the surface of the soil all year or for varying periods during the year, including during the growing season. Wetlands can be influenced by local geologic conditions that provide the parent material for soils, influence groundwater chemistry, and affect wetland vegetation. Wetlands in the Mid-Coast have either organic soils (muck, mucky peats, fibrous peats, or combinations of these) that are saturated perennially or mineral soils (sand, silt, and silty loams, sandy loams, or clay loams) that may be flooded in the winter and moist or dry in the summer. The main types of wetlands in the Mid-Coast, each with unique soils and vegetation communities, are aquatic beds, marshes, peatlands, wet prairies, shrub swamps, and forested swamps.

Mid-Coast Areas of Ecological Importance

 

ODFW established the Oregon Conservation Strategy (OCS), which identifies areas of ecological importance, or Conservation Opportunity Areas - where broad fish and wildlife conservation goals would best me met. The areas of ecological importance in the Mid-Coast, including the important habitat that exists in each location:

  • Alsea Estuary-Alsea River - Overwintering habitat for migrating waterfowl and rearing habitat for coastal salmonid

  • Beaver Creek - Diverse habitat from beach to old-growth forests

  • Depoe Bay Area - Productive rocky shore for fish and wildlife use

  • Devil's Lake - Peat marsh near mouth of Rock Creek, an important coho rearing stream

  • Salmon River Estuary-Cascade Head - Diverse habitats; includes Cascade Head Scenic Research Area; Habitat for threethreatened and endangered species

  • Siletz Bay - Siletz estuary provides diverse and complex habitat

  • Siletz River - Sandstone/basalt river system with flashy winter river flow and private forestland

  • Yachats River Area - Narrow river channel with wide shallow mouth at ocean; steep coastal mountains

  • Yaquina Bay - Eelgrass beds, intertidal and subtidal shellfish beds, native oyster beds, and nesting eagles and ospreys along estuary

Yachats River Area. Photo credit: Doug Cottam, ODFW.

Species of Interest and Habitat Needs​


Seven species of salmon, green and white sturgeon, beaver, and three species of lamprey are species of interest in the Mid-Coast. Invasive species are considered species of interest because they can have a disproportionate effect on the ecosystem.

 

​Snapshot Ecological Summaries of Major Drainage Basins

 

Salmon River Drainage Area​

The Salmon River drains 75 square miles and has 104.5 miles of streams. Tributaries to the Salmon River include Bear Creek, Little Salmon River, Salmon Creek, Slick Rock Creek, Treat River, and Trout Creek. The average slope in the basin is 14 degrees and less than 1% of the basin is above 3,000 feet in elevation. Average annual precipitation is 118 inches, and some areas of the watershed receive higher average annual precipitation. Fog drip contributes to as much as 20 inches of precipitation during the dry summer months. The Salmon River Watershed has basalt geology and an important estuary, which is used by juvenile salmon and has been the site of major restoration. There are several significant surface water points of diversion in the Salmon River Watershed.

 

Areas of Ecological Importance:

 

Species of Interest: Pacific Lamprey, Chum, Fall Chinook, Coho, Winter Steelhead, Coastal Cutthroat Trout

Siletz Bay - Ocean Tributaries

The Drift Creek watershed is part of the Siletz River COA and drains about 41 square miles and 63 miles of streams into the Siletz Bay. Drift Creek is a source water for Kernville-Gleneden-Lincoln Beach Water District. Stream flow restoration is a high priority in the Drift Creek watershed.Devil’s Lake Watershed is also an area of ecological importance inthe Siletz Bay-Ocean Tributaries drainage basin. The watershed provides coastal coho rearing and spawning habitat. Protected areas in Devil’s Lake Watershed include D River State Recreation Site and Devil’s Lake State Recreation Area. Rock Creek flows into Devil’s Lake and is “one of the most important coho producing streams on the coast,” according to ODFW. The mouth of the creek contains several acres of peat marsh.

 

Areas of Ecological Importance:

 

Species of Interest: Coho, Fall Chinook, Pacific Lamprey, Winter Steelhead

 

Siletz River Drainage Area

The Siletz River drains 305 square miles and includes 458 miles of stream length. Portions of the watershed lie within the Siuslaw National Forest. The watershed geology is a mixture of volcanic rocks and sandstone. Tributaries to the Siletz River include Cedar Creek, Euchre Creek, Gravel Creek, North and South Fork Siletz, Rock Creek, and Sunshine Creek. The average annual precipitation in the Siletz River Watershed is 104 inches. Higher up in the watershed, precipitation increases and slope increases. Precipitation in the Gravel Creek watershed is 144 inches per year and slope increases from 17% at the mouth of the Siletz River to 20% in the Gravel Creek watershed. Several municipalities withdraw water from the Siletz River Watershed.The northern 2/3 of the Upper Siletz (North Fork sub-watershed) generally has streams with high gradients while the southern 1/3 of the watershed mostly consists of broad, flat alluvial bottom that was once logged and homesteaded.

 

The Siletz River drainage area has a diversity of species and a large restoration project and study in the Mill Creek watershed to improve fish habitat and monitor the outcomes of stream restoration. The watershed has several significant surface water points of diversion.

 

Areas of Ecological Importance:

 

Species of Interest: Fall Chinook, Spring Chinook, Chum, Coho (NMFS has identified the Siletz River, Middle Siletz, and Lower Siletz as critical habitat for Oregon Coast Coho Salmon), Summer Steelhead (Siletz River Watershed has the only coastal origin population of summer Steelhead in Oregon),  Winter Steelhead, Cutthroat Trout, Pacific Lamprey

Depoe Bay - Ocean Tributaries

The northern portion of the Depoe Bay-Ocean Tributaries drainage area is located within the Depoe Bay Conservation Opportunity Area. Rocky Shores in the Depoe Bay Area are nesting sites for wildlife species.

 

Areas of Ecological Importance:

 

Species of Interest: Coho, Winter Steelhead

 

Yaquina River Drainage Area

 

The Yaquina River drains 210 square miles and has 294 miles of streams. Tributaries to the Yaquina River include Depot Creek, Big Elk Creek, Little Elk Creek, Mill Creek, Olalla Creek, and Thornton Creek. The average slope in the basin is 14.7 degrees and the mean elevation is 535 feet with almost no area above 3,000 feet. The watershed receives a mean annual precipitation of 80 inches. The geology in the Yaquina Watershed is predominantly Tyee sandstone.

 

The Yaquina River drainage area supports industrial fishing, including the largest commercial fishing center in the Mid-Coast (the City of Newport). The geology is primarily sandstone geology, which provides an abundant fine sediment supply to the watershed. YaquinaBay provides habitat for white and green sturgeon. There are several significant surface water points of diversion in the lower portions of the watershed below the confluence of the Yaquina River and Big Elk Creek.

Areas of Ecological Importance:

  • Yaquina Bay is designated as critical habitat for green sturgeon. The Upper Yaquina River, Lower Yaquina River, Big Elk Creek, and Yaquina Bay are all designated as critical habitat for Oregon coast coho. Mill Creek is has the most southern, stable population of Chum salmon on the coast 

  • Mill Creek

  • Big Elk Creek

  • Yaquina Bay

  • Yaquina River (upper and lower)

 

Species of Interest: Fall Chinook, Chum, Coho, Pacific Lamprey, Winter Steelhead, White Sturgeon, Green Sturgeon, Coastal Cutthroat Trout

 

The watershed is home to several federally listed species, including the marbled murrelet, western snowy plover, Northern spotted owl, coho salmon, and Oregon silverspot butterfly. Chum salmon and white sturgeon also are present in the watershed. In addition, The Wetlands Conservancy notes there are several species of conservation concern in the Yaquina River Watershed, including the northern red-legged frog, mountain quail, purple martin, green and white sturgeon, and steelhead.
 

Beaver Creek-Ocean Tributaries

The Beaver Creek watershed is an area of ecological importance in the Beaver Creek-Ocean Tributaries Drainage Basin. Beaver Creek Watershed is larger than the Yachats River, draining 64 square miles. Tributaries include North Fork and South Fork Beaver Creek, Oliver Creek, Elkhorn Creek, Bowers Creek, and Peterson Creek. The creek drains directly into the Pacific Ocean at Ona Beach and has 42 miles of streams. The Beaver Creek Watershed is a Conservation Opportunity Area and is ecologically important due to extensive peat bog wetlands, late successional forest on USFS property, and bald eagle nesting sites. Protected areas within the Beaver Creek Conservation Opportunity Area include the Beaver Creek State Natural Area, Drift Creek Wilderness, Estella Matilda Happ Preserve, Ona Beach State Park, Seal Rock Wetland Preserve, and Siuslaw National Forest.

 

Areas of Ecological Importance:

 

Species of Interest: Fall Chinook, Coho, Winter Steelhead, Pacific Lamprey

Alsea River Drainage Area

The Alsea River drains 459 square miles and has 517 miles of streams.Tributaries to the Alsea River include Canal Creek, Drift Creek, Fall Creek, Five Rivers, Lobster Creek, and the South Fork Alsea. Portions of the watershed are in the Siuslaw National Forest. The City of Waldport uses Eckman Creek, a tributary to Alsea Bay, as one of its drinking water sources. Eckman Creek is dammed near Highway 34, creating Eckman Lake. The average slope in the watershed is 20 degrees and the mean elevation is 1,024 feet. Less than 1% of the watershed is above 3,000 feet. The Alsea River Watershed receives an average annual precipitation of 87.47 inches.

 

The Alsea River drainage area includes a large river with a small bay and supports a large diversity of species. Alsea Bay supports abundant salmonids and small populations of green sturgeon.Valley floors in the watershed support agriculture and rural development. There are several significant surface water points of diversion in the upper portion of the Alsea River.

 

Areas of Ecological Importance:

 

Species of Interest: Fall Chinook, Spring Chinook, Chum, Coho, Pacific Lamprey, Summer Steelhead, Winter Steelhead, Green Sturgeon, Coastal Cutthroat Trout

Yachats River and Ocean Tributaries

The Yachats River drains 43 square miles and has 58 miles of streams.Tributaries to the Yachats River include the North Fork Yachats, School Fork, and Stump Creek. The average slope of the watershed 18 degrees and the average elevation is 696 feet. None of the Yachats River Watershed is above 3,000 feet. The watershed receives an average annual precipitation of 91 inches, which does not vary significantly throughout the watershed. The City of Yachats receives its water supply from Salmon Creek and Reedy Creek, but has an emergency intake on the Yachats River. Portions of the Yachats River Watershed are within the Siuslaw National Forest.

 

The Yachats River drainage area is characterized by basalt geology, habitat for steelhead, and a small estuary. There are several significant surface water points of diversion in the lower portions of the watershed.

 

Areas of Ecological Importance:

 

Species of Interest: Fall Chinook, Coho, Pacific Lamprey, Winter Steelhead, Coastal Cutthroat Trout

 

The Yachats River Watershed is also home to marbled murrelet and spotted owl nesting sites.

Habitat Degradation 

 

The main threats to aquatic habitats in the Mid-Coast include reduction in stream complexity, barriers to fish passage, reduced water quality, and reduced water quantity or alterations in streamflow. Specific factors influencing regional habitat quality and decline of salmon include: ocean conditions, land use practices, landslides, fish hatcheries, and major flood events. Human-induced factors, such as habitat degradation, water diversions, land use practices, and artificial propagation, have contributed to the decline of coho salmon. Reduced amount and complexity of habitat, degraded water quality, blocked/impaired fish passage, and uncertainty that there is an adequate combination of voluntary and regulatory mechanisms to ensure success are limiting factors. Salmon populations in streams with water quantity or water quality limitations, or simplified stream channels, may be more susceptible to further habitat degradations that result in additional stress.

Habitat degradation in aquatic habitats include stream channel simplification and incision, warm stream temperatures, altered streamflow timing and watershed function, excess turbidity at periods of peak streamflow, and impairments or barriers to fish passage. Stream channel simplification and incision can arise from removing riparian vegetation, removing large woody debris from streams, and channelizing streams. Historical land use practices are the source of stream channel simplification and incision in many areas. Warm temperatures can occur from lack of riparian vegetation, reduced streamflow, and stream channel simplification. Altered streamflow timing can result from land management practices and streamflow withdrawals, both of which affect how water moves through the landscape (i.e., watershed function). Land management practices can affect the rate at which fine sediments from the landscape are transported to streams and also can affect the magnitude of peak flows, which may combine to increase turbidity to levels that negatively affect wildlife and impair or prohibit water treatment for human consumption.
 

Habitat restoration projects are occurring throughout the Mid-Coast to improve habitat conditions and reduce further degradation. These projects include adding large woody debris into streams, increasing fish rearing areas off the main channel’s streams, supporting gravel substrate used for spawning and deep pools, increasing streamflow during key times of the year for fish species and in the summer to reduce settling of fine sediment inputs, maintaining riparian vegetation for shading and filtering, and lower water temperatures, improving roads to reduce sediment inputs, and encouraging beaver dam formation.

© 2020 Oregon Mid-Coast Water Planning Partnership