Appendix D: Summary of Olympia Stream Basin Traits (Source: Aquatic Habitat Evaluation and Management Study, City of Olympia, 1999)

After an overview of data sources and overall basin characteristics, this appendix summarizes the available information relevant to the evaluation of aquatic habitat conditions. Data is organized based on functional relationships presented and discussed in the University of Washington research cited in the study report: Basin conditions (extent of development and hydrologic regime) Riparian conditions (integrity of the riparian corridor) Instream and wetland habitat conditions (physical habitat and water quality) Aquatic biota (fish and macro-invertebrates)

This information is summarized further in Table 3.2 of the Aquatic Habitat Evaluation and Management Study report. The basins are discussed in order of the rankings described in Section 3.5 of the report.

Data Sources Primary data sources consulted for this summary are: Comprehensive Drainage Basin Plans for Indian-Moxlie Creeks (1993), Percival Creek (1993), Woodard Creek (1995), Chambers/Ward/Hewitt (1995), and Green Cove Creek (1998). Basin Reconnaissance and Public Involvement Report (1993), containing information about Mission, Ellis, and Schneider Creeks. Thurston County's Water Quality Monitoring Report for the 1996-97 water year and previous similar reports. Olympia's Wildlife Habitat Study Final Recommendations (1994). Additional information on Olympia’s streams and wetlands presented in biological investigations, watershed plans and research papers.

Overview of Creek Drainage Basins Olympia’s eight major drainage basins are shown in Figure 1.1 in relationship to the City limits and Urban Growth Area.

Budd Inlet/Deschutes River Watershed Ellis Mission Indian-Moxlie Chambers/Ward/Hewitt Percival Schneider

Henderson Inlet Watershed Woodard

Eld Inlet Watershed Green Cove

D-1 The following summary of basin conditions is excerpted from the Basin Reconnaissance and Public Involvement Study (Olympia 1993).

Population and Land Use Thurston County has experienced a steady increase in population since 1900. Before the 1960s, the county’s average growth rate was about 20% per decade. Population has doubled since 1970. The county’s rapid growth has made it the eight most popuous county in the state despite its relatively small size. The current growth trend, spurred by expanding service, trade, and government services, is expected to continue.

Growth outside the urban core has accounted for 75% of the area’s new development, most of which can be described as low density urban sprawl. In an effort to restrict sprawl, the Cities of Olympia, Lacey, and Tumwater have delineated an 84-square-mile Urban Growth Area (UGA). Within the UGA, land use policies and infrastructure are designed to encourage high density housing and commercial development; outside the UGA is intended to remain in low density rural use. The majority of the basins included in this report fall within the UGA.

Climate The South Puget Sound region has a marine climate typical of the west coast. Summers are relatively dry and cool; winters are mild and wet. Average annual precipitation is about 53 inches. During the wet season, rainfall is usually of light to moderate intensity and continuous over a long period. Typical rainfall is as follows:

Approximate Seasonal Rainfall (inches) Fall 10 Winter 29 Spring 10 Summer 4

Major storm events in the Olympia area have been evaluated for the purpose of characterizing stormwater runoff quantities and sizing conveyance and storage facilities. This evaluation generated theoretical design storms that are defined as the precipitation expected in a 24-hour period from a storm of a given recurrence interval. Although precipitation varies with geographic location, the 24-hour rainfall values are used for stormwater facility design throughout northern Thurston County (Drainage Design and Erosion Control Manual for the Thurston Region, 1994).

Storm Recurrence Precipitation (years) (inches/24 hours) 2 2.80 5 3.75 10 4.35 25 5.10 50 5.65 100 6.15

D-2 The prolonged wet season in the Puget Sound region presents unique problems in estimating the quantity of runoff generated by a storm of specific intensity and duration. Often the level of moisture in the soil profile immediately preceding a storm event is high. Given a saturated soil, only minimal amounts of precipitation can be infiltrated. The likelihood of high antecedent moisture levels in soils requires extra care when predicting the amount of runoff that can be expected from a storm event.

Topography The basins described in this report are located between the mountainous Black Hills on the west and expansive prairies on the east. These basins surround and drain to Budd Henderson, and Eld Inlets, the southernmost points of Puget Sound. Most creeks have low to medium gradients and are often fed by numerous groundwater springs. Most of the creeks have formed deeply incised banks in downstream portions of the channels.

In general, land area in the basins is moderately sloped with frequent rolling terraces and occasional small glacial depressions known as kettles. In the southeastern areas, these small depressions often contain lakes, which are groundwater fed and commonly have no surface inlets or outlets.

Geology and Soils The geologic history of the Olympia area plays a major role in determining the surface and subsurface drainage characteristics of the basins. Glacial ice from the north entered the South Puget Sound region at least several times. The low topography on the east side of the Olympic Peninsula routed a portion of the progressing glaciers into northern Thurston County. As the glaciers advanced and then retreated, several types of material were deposited in creek channels and lowlands. On the westside of Olympia and to the north, the glaciers left primarily till at the surface, which occurs as gravelly creekbeds providing good habitat for anadromous fish. On the eastside and to the southeast, surface soils are primarily sand associated with the Lake Russell Deposits; this material dominates creek substrate, offering lower quality anadromous fish habitat and resulting in less instream biotic diversity.

The Vashon glaciation is of primary importance to local geology. This glacial event receded only 10,000 years ago, after covering the area for 2,000 years. Glacial advancement over existing landforms compacted underlying sand, silt, clay and gravel. The resulting concrete-like material known as glacial till has low permeability and therefore generates considerable stormwater runoff. The tills are fairly stable in slopes.

Conversely the material deposited ahead of advancing glaciers by melting ice, known as advance outwash, is composed of highly porous sands and gravels. A second type of outwash, recessional, was formed by retreating glaciers. The outwash soils are deeper and much better drained than the till soils. Outwash materials with a high content of silt and sand are prone to erosion; those that are more sorted and contain larger material are more resistant to erosion.

Another soil group, clay, formed during glacial compaction of the fine material deposited in pre- glacial lakes. Wetlands typically contain unique hydric soils. These soils are saturated, flooded, or ponded long enough during the growing season to develop anaerobic conditions that favor the growth and regeneration of specific vegetative types.

D-3 Recent glacial activity also developed a unique land form in what is now the southeast portion of Olympia. Upland depressions known as kettles or potholes were formed by the deposition of materials form the receding Vashon glacier. These depressions re typically closed to surface discharge, steeply sloped, and commonly support wetland vegetation.

Critical Areas Critical areas within the basins include wetlands, floodplains, aquifers, shorelines, and geologic formations. Development restrictions apply to many of these areas as delineated on local zoning maps.

Wetlands. Wetlands are usually found in low-lying areas where land and water come together. These areas can occur along coastal shorelines, river and stream banks, around the shores of lakes, or in areas fed by underground springs. Wetlands are distinguished by their soil types and vegetation. In wetlands, water is present at or near the surface for extended periods of time during the growing season, thereby affecting the traits of the soils. Only plans adapted to living in these conditions can survive in wetlands. Wetlands provide a number of valuable ecological functions that commonly include water purification, flood control, shoreline stabilization, recharge of groundwater and streams, and wildlife and fish habitat.

The headwaters of nearly all the streams in Olympia are located in wetlands. Many of these wetlands have been encroached upon or completely eliminated. Basins located within the highly urbanized areas of Olympia now have only small, if any wetlands remaining. Less developed basins contain larger, more extensive wetlands.

Shoreline areas. The basins contain several relatively large lakes, many of which are protected by the requirements of the Shoreline Master Program for the Thurston region. Ward and Hewitt Lakes are designated as rural environments; Chambers is designated as a conservancy environment. Saltwater shorelines in Thurston County are designated as conservancy environments, except for Budd Inlet south of Priest Point Park, which is an urban environment. With the exception of Percival Creek, Olympia creeks have annual mean flows less than 20 cubic feet per second (cfs) and therefore are not regulated by the Shoreline Master Program.

Floodplains. Floodplains are typically located adjacent to low-lying segments of the creeks, lakes, and wetlands. Floodplains are protected in order to minimize onsite and downstream flooding as well as important habitat.

Aquifer sensitive areas. Aquifer sensitive areas delineated by Thurston County encompass a large portion of the creek basins. These areas have aquifers with relatively porous overlying soil types. The porous soils allow rapid and poorly filtered recharge from surface waters. The potential for contamination of groundwater by pollutants is relatively high in these areas.

Steep slopes. Steep and unstable slopes are located in nearly all the basins. Many creeks flow through deeply incised canyons composed of inherently unstable soils. Development and the associated discharge of stormwater to creeks can lead to bank failures on these slopes.

D-4 Green Cove Creek Green Cove Creek basin lies on a fairly level peninsula between Eld Inlet and Budd Inlet, at an elevation of 150 - 200 feet above sea level. Slopes generally range from 0-3%, except for the steep slopes of the Green Cove Creek ravine. A low ridge runs east-west across the basin from Kaiser Road almost to Division Street. The flat topography makes a precise definition of boundaries difficult.

The creek originates at the outlet of Lake Louise and flows through extensive wetlands, where the channel sometimes disappears. After crossing under Evergreen Parkway, the creek enters a forested area. About 1,200 feet south of 36th Avenue NW, the gradient steepens and the creek enters a steep, forested ravine which confines the creek until it reaches the mudflats and passes in a flat straight channel into Eld Inlet at Green Cove. An unnamed tributary joins the creek south of Evergreen Parkway.

Creek Length: 3.6 miles Stream Order: 2 Basin Size: 2,626 acres or 4.1 square miles

Information on the basin relevant to evaluation of aquatic habitat conditions is summarized below. For details, see the Green Cove Creek Comprehensive Drainage Basin Plan (Sound Ecological Services 1998), particularly sections on land use, hydrology, creek corridor, in-stream characteristics, fish and wildlife habitat, and water quality.

Basin Conditions Level of urbanization The 4.1 square-mile basin is bounded roughly by Cooper Point Road on the east, Mud Bay Road on the south, Overhulse Road on the west, and Sunset Beach Drive on the north. The basin, encompassing portions of Olympia’s west side and urbanizing areas of Thurston County, is 24% developed. Most commercial and suburban residential development is in the eastern, urban half. The southeast corner of the basin along Cooper Point Rd. contains the highest density residential development. Commercial development is centered on the southernmost part of the basin, near the Mud Bay Road, Cooper Point Road intersection. The unincorporated county to the west and north is characterized by lower density residential and semi-rural land uses. A substantial amount of new commercial and high-density residential development is being planned or constructed throughout the basin.

Table A-1 summarizes University of Washington data on developed and undeveloped areas, impervious surface and road density of the upper, middle, and lower creek sub-basins studied.

Hydrology Impervious surfaces cover about 8% of the basin. Most moderate and high density developments have onsite stormwater treatment and storage facilities. Still, drainage systems create unnaturally high seasonal groundwater and stream flows that sometimes create flooding. Soils are largely glacial till with low infiltration rates, especially after development. This effect is expected to increase as new development eliminates more forest cover and drains more runoff into stormwater facilities, streams, and wetlands.

D-5 Extensive wetland systems help buffer the creek from peak flows. The basin has approximately 299 acres of wetlands, or 11.8% of the total basin area. Since the 1850s, approximately 250 acres, or 45% of historic wetlands have been lost.

Riparian Corridor South of Evergreen Parkway, the riparian zone is broad and flat. Vegetation is dominated by wetland shrubs and emergent species. Non-native reed canary grass has invaded the native vegetation in disturbed areas. Small segments of the upper creek's riparian zone contain mixed forest vegetation. In general, the riparian corridor and wetlands are intact, with healthy native vegetation.

North of Evergreen Parkway, Green Cove Creek's riparian zone is densely vegetated with streamside species such as Oregon ash, black cottonwood, red alder, and western red cedar. Shrub species include vine maple, salmonberry, serviceberry, beaked hazel, and red osier dogwood.

Four roads cross the stream.

Table A-1 summarizes University of Washington data on riparian corridor characteristics of the stream segments studied, including land cover, developed area, and dominant vegetation.

In-Stream and Wetland Habitat Conditions Physical The overall condition of habitat in Green Cove Creek is good to excellent. In some creek sections the channel is poorly defined or nonexistent.

The creek contains good spawning habitat for coho and chum salmon and fairly abundant, high quality summer rearing habitat for coho. Chum do not rear in streams in the summer, but winter flows and ponds are adequate for their brief rearing period. The potential for continued good chum and coho spawning habitat conditions is high.

Major threats to spawning habitat include the potential for increased peak flow, increased fine sediment inputs, and loss of large woody debris and streamside vegetation. Stormwater runoff generated in the basin is typically discharged to the creek or wetlands. Stormwater discharges have not significantly degraded salmon habitat in the creek, but increased peak flows could cause significant downcutting and lateral stream bank erosion. The result would be significantly degraded fish habitat due to loss of pools, cover and spawning gravels.

Table A-1 summarizes University of Washington data on in-stream physical characteristics of the stream segments studied, including gradient, bank stability, large woody debris, and pools and riffles. The Green Cove Comprehensive Basin Plan includes the results of a detailed salmon habitat assessment completed in 1995. The results are summarized in Table A-3.

The extensive wetland adjacent to Green Cove Creek between Lake Louise and Evergreen Parkway, and the 160-acre Grass Lake Refuge north of Mud Bay Road and west of Cooper Point Road have been identified by the City of Olympia as significant wildlife habitat (Shapiro 1994). Smaller remnant wetlands are located throughout the upper basin. Some wetlands still maintain high biological integrity, despite human alterations. Wetland habitat is excellent in the City-

D-6 owned Grass Lake Refuge. Wetland areas may be inaccessible to migrating fish and often contain inadequate water depths for beneficial fish habitat.

Water quality Green Cove Creek has been given a Class A water quality designation by the Washington Department of Ecology. Water quality is typically rated "good" based on long-term monitoring results by Thurston County Environmental Health Department (Thurston County 1997).

A good water quality rating indicates that samples usually meet water quality standards, or violate only one part of the two-part fecal coliform standard, or the violation results from natural conditions. Green Cove Creek has been monitored by Thurston County under ambient conditions since 1987. Fecal coliform standards have been met since 1988 with the exception of 1995. The only documented problems have been related to stormwater runoff from residential areas i.e. not agricultural.

Although the use of sanitary sewer service is expanding, most of the basin is served by private wells and septic tanks. Stormwater runoff contributes pulses of fecal coliform bacteria contamination from septic systems, pet waste, and wildlife to the stream that may affect shellfish beds in Green Cove. However, water quality does not seem to limit fish use in Green Cove Creek. Increased new development will generate more construction-related sediments and runoff carrying pollutants into Green Cove Creek.

Aquatic Biota Benthic Macro-Invertebrates A single sample by Thurston County Environmental Health Department on October 1, 1998 had a B-IBI rating of 30 (moderate biological integrity), as shown in Table A-3.

Fish Anadromous fish found in Green Cove Creek include chinook, chum, and coho salmon, steelhead, and sea-run cutthroat trout. Chum salmon spawn near the mouth and return to the sea after a brief rearing period. The Department of Fish and Wildlife (DFW) uses Green Cove Creek from the mouth to Evergreen Parkway as an index stream for chum salmon.

Coho remain in the creek and seek out wetlands and slow-water areas to rear for up to one year before migrating to salt water. Coho have been observed at least as far upstream as the second culvert under Kaiser Road by the sewer lift station. The DFW releases coho fingerlings to the creek at the outlet to Louise Lake.

Resident species in the creek include western brook lamprey, Olympia mud minnow and possibly eastern brook trout. Cottids and sticklebacks probably occur. The DFW planted game fish in the creek several times between 1981 - 1990.

Marine Mammals and Shellfish There is limited commercial shellfish harvesting in Eld inlet.

D-7 Woodard Creek The Woodard Creek basin encompasses eight square miles (5,090 acres) of mostly level, glacially formed terrain south of Henderson Inlet. Most of the basin is at an elevation less than 200 feet above sea level. The basin includes the southern portion of Dickerson Point, a level peninsula with steep, ravine-cut bluffs dropping to the marine shorelines. Several depressions contain small wetlands and a slight rise on the peninsula forms the basin's western boundary.

Woodard Creek flows out of a 45-acre wetland contained in a small, steep-sided depression just south of the Pacific Avenue/Interstate 5 interchange, at an elevation of about 150 feet above sea level. The creek flows north through low-lying wetlands and enters a flat-bottomed ravine on St. Peter's Hospital property north of Martin Way; an unnamed tributary enters the creek from the southwest in this area. The creek winds through a strip of riparian wetlands, then the ravine narrows and steepens as it cuts through the Dickerson Point peninsula north of 36th Avenue NE. The creek empties into Henderson Inlet midway along its western shore, at the estuary of Woodard Bay. The length of the creek is characterized by wetlands and wooded terrain. The gradual rises and depressions of land contain many small wetlands.

Creek Length: 7.5 miles Stream Order: 2 Basin Size: 5,090 acres

Information on the basin relevant to evaluation of aquatic habitat conditions is summarized below. For details, see the Woodland and Woodard Creek Comprehensive Drainage Basin Plan (Thurston County 1995), particularly sections on land use, hydrology, water quality, fish, shellfish, and wildlife.

Basin Conditions Level of urbanization About 25% of the basin is developed and the remaining 75% is undeveloped forest and grassland (1995). High-density commercial and industrial land uses dominate the southern Woodard Creek basin, which include two freeway interchanges, South Sound Center, Olympia Square, and light industrial/commercial development on Fones Road. Medium-to-high density residential areas surround these commercial zones. North of Martin Way, moderate density residential and commercial development is occurring along Lilly Road; the creek corridor itself remains sparsely developed with rural and semi-rural development. A significant portion of the basin is outside Olympia’s Urban Growth Area. If development continues as envisioned in local comprehensive plans, many remaining forests will be developed and most low-density residential areas will be covered to medium density.

Hydrology The basin's hydrologic regime has been severely impacted by alterations associated with industrial and commercial development in the upstream portions, which drain to the wetland at the headwaters of the creek, effectively making South Sound Center parking lot into the creek's headwaters.

Approximately 15-20% of the basin is covered with impervious surface, primarily in the southern part of the basin, which is almost 80% covered by impervious surfaces. Development of impervious surfaces has nearly doubled natural peak stream flows and reduced base flow.

D-8

Peak flows have increased significantly over natural flows. Extreme peak flows during heavy rains from the highly developed commercial and industrial area have a pronounced effect near the creek’s headwaters. However, peak flows at the mouth have increased proportionally less than upstream, because the downstream basin has not been developed as intensively as the upper basin. Future development threatens to cause more habitat damage by increasing impervious surfaces and reducing forested areas that mitigate runoff and peak flows.

Extensive wetlands absorb runoff and reduce stormwater impacts on downstream flows. The basin contains about 334 acres of inventoried wetlands directly associated with the creek, or about 7.5% of the total basin area. Many developments in the basin have onsite stormwater management facilities.

Riparian Corridor In its lower reaches, the creek corridor consists of open farmland and rural residences, interspersed with areas of mixed deciduous and coniferous forest. However, removal of streamside vegetation for farming and residential uses has increased erosion, removed food sources, and reduced overhead shading. There are six road crossings; the three major crossings -- Pacific Avenue, Martin Way, and I-5 -- are clustered together near the headwaters.

In-Stream and Wetland Habitat Conditions Physical Overall habitat conditions are fair to good. The stream has good spawning and rearing habitat conditions for anadromous fish in some reaches. The lower reaches have fairly pristine wetlands, providing good habitat for anadromous and resident fish; the urban reaches show signs of degradation.

About 6.9 miles of the main stem of Woodard Creek are accessible to anadromous fish. Between 36th Avenue NE and the headwaters, the creek has a low gradient and a pool/glide configuration with isolated riffles. Downstream from 36th Avenue, the creek has a low to moderate gradient and a good pool/riffle ratio.

However, increased winter flood flows have significantly degraded fish habitat in some reaches of the creek, causing erosion and sedimentation, scouring of spawning gravels, loss of large logs, and blocking of fish passage. Low summer flows have reduced the ability of smolts to migrate to marine water and prevented summer-run salmon from migrating up stream. Culverts at the road crossings apparently have blocked fish passage; the culvert at 36th Ave. NE may be a partial barrier.

The 45-acre wetland at the headwaters of the creek and the 44-acre wetland north of Martin Way on St. Peter's Hospital property have been identified by the City of Olympia as significant wildlife habitat, slated for acquisition or additional protection (Shapiro 1994). An additional 133 acres of riparian wetlands between Pacific Avenue and South Bay Road also provide rearing habitat for coho salmon.

The mouth of Woodard Creek is an estuarine wetland, currently protected as a natural area by the Washington Department of Natural Resources.

Water quality

D-9 Henderson Inlet and its tributaries are Washington Class AA waters, the highest water quality designation with the most stringent standards. Water quality in Woodard Creek is typically rated "fair" based on monitoring results by Thurston County Environmental Health Department (Thurston County 1997).

Fair water quality ratings in most of the stream indicate that samples did not meet one or more water quality standards. The primary pollutant sources are urban stormwater runoff in the headwaters and upstream portions and failing septic systems and the numerous animal-keeping farm sites located along the middle stretch of the stream.

Fecal coliform, phosphorous, oil and grease, and total petroleum hydrocarbons are chronic pollutants from untreated stormwater discharges that exceed water quality standards. Metals detected in samples indicate potential contamination, mostly likely from stormwater.

Aquatic Biota Benthic Macro-Invertebrates A single sample by Thurston County Environmental Health Department on October 1, 1998 had a B-IBI rating of 36 (moderate biological integrity), as shown in Table A-3.

Fish Chum and coho salmon, steelhead, and sea-run cutthrout trout spawn primarily in the gravel riffles downstream of 36th Avenue, but spawning has been observed in isolated riffles as far upstream as the Pacific Avenue culvert. Juveniles use the entire 6.9 miles for year-round and seasonal rearing. WDFW annually plants coho in the stream.

Resident species include rainbow rout, cutthroat trout, sculpins, lampreys, sticklebacks, Olympic mud minnow, yellow perch, large scaled sucker, and brown bullhead (WDFW 1990, Woodard and Woodland Creeks).

Fish population inventories have not been conducted frequently enough to determine a significant trend, but long-term landowners along the creek report a dramatic decline in salmon populations.

Marine Mammals and Shellfish The second largest harbor seal colony in southern Puget Sound resides at the mouth of Chapman Bay, adjacent to Woodard Bay. The mouth of the creek provides good habitat for shorebirds and wading birds such as great blue heron.

Henderson Inlet is one of Puget Sound's most productive shellfish harvesting areas, dating from the mid-19th century. Shellfish include oysters, clams, mussels, and geoducks. However, a total of 163 acres of commercial shellfish beds have been closed because of fecal coliform pollution since 1983.

D-10 Percival Creek Percival Creek Basin is located between Black Hills on the west and Interstate-5 on the east. The drainage area is moderately sloped with elevations ranging from sea level to 500 feet. The basin encompasses Trosper Lake, Ken Lake, and several extensive wetlands.

Percival Creek is one of the largest stream systems in the urbanizing area of north Thurston County. It consists of a main stem, one major tributary, and several minor tributaries. Numerous year-round and seasonal tributaries, springs, and seeps enter the creek. The main stem of Percival Creek begins at Trosper Lake and flows north for about 2.4 miles to its confluence with the main tributary, the Black Lake Drainage Ditch. The ditch, originally a natural channel, was ditched in the 1920s to improve drainage to that end of the Black Lake wetlands. The ditch originates at Black Lake and flows northerly for about two miles before turning east near Mottman Road to the confluence. Downstream of the confluence, the creek flows in a steep canyon for about 1.2 miles, crossing under I-5 and Cooper Point Road, to its mouth at Percival Cove on the west side of Capital Lake.

Creek Length: Percival Creek 3.6 miles; Black Lake ditch 2 miles. Stream Order: 2 Basin Size: 5,300 acres

Information on the basin relevant to evaluation of aquatic habitat conditions is summarized below. For details, see the Percival Creek Comprehensive Drainage Basin Plan (Olympia 1993), particularly sections on land cover and use, hydrology, creek corridor, in-stream characteristics, water quality, and fish and wildlife.

Basin Conditions Level of urbanization The Percival Creek basin is approximately 8.3 square miles, or 5,300 acres, and encompasses the urbanized and rapidly developing west side of Olympia, and developing areas of Tumwater and Thurston County. Approximately 50% of the basin is developed; the remainder is forests, pastures, and wetlands. Most development in the basin has occurred in the last 10-20 years, and a substantial amount of the region’s new commercial and high-density residential development is being constructed there. High density land use expected to increase.

Table A-1 summarizes University of Washington data on developed and undeveloped areas, impervious surface and road density of the sub-basins studied. These are: lower Percival Creek from mouth to fork; middle Percival Creek from the fork to Chapparell Drive S.W., headwater area above Chapparell Drive; and the Black Lake Ditch.

Hydrology Approximately 20-25% of the basin (950 acres) is covered by impervious surfaces. Creek flows were increased with construction of the Black Lake Drainage Ditch in the 1920's and since then urbanization has substantially increased creek flows and flooding.

Numerous on-site and regional stormwater storage facilities have been constructed. Some stormwater management systems in new development in the basin are highly effective, others are undersized.

D-11 Many of the wetlands in Cooper Point/Black Lake Boulevard area have been eliminated. However, flooding and stormwater-related water quality problems are moderated by storm drainage detention facilities and the extensive remaining wetlands along the creek and Black Lake Ditch.

Riparian Corridor The majority of Percival Creek's riparian zone is vegetated with common streamside species including Douglas fir, red alder, Western red cedar, and various shrub species. Over 60% of the corridor is undeveloped, with protected buffers greater than 100 feet wide along more than half of the corridor. The buffer is continuous along the downstream portion where the creek flows through a deep canyon. Extensive streamside wetlands are adjacent to the upstream portions of the creek and the Black Lake Drainage Ditch.

Streamside buffers ranging form 25-100 feet have been established to protect the riparian zone from development. However, urbanization is resulting in gradual loss of beneficial tree species. There are eight road crossings including I-5; none in downstream portion of the creek below Cooper Point Road.

Table A-1 summarizes University of Washington data on riparian corridor characteristics of the stream segments studied, including land cover, developed area, and dominant vegetation.

In-Stream and Wetland Habitat Conditions Physical Overall aquatic habitat in Percival Creek and the Black Lake Drainage Ditch is fair to good. Habitat remains largely intact but is subject to continual degradation by the effecs of urbanization. In addition, the important estuarine environment at the mouth of the creek was eliminated by creation of Capital Lake.

Black Lake Drainage Ditch has good spawning gravels frequented annually by chinook, and low gradient areas for rearing. The quantity of fine sediments in the creek substrate are fair. Shading levels are low to adequate. The amount of in-channel large woody debris (LWD) is low, and future recruitment potential from streambanks is poor. Low gradient, slow moving waters, riparian shading, and summer water temperatures create fairly good rearing habitat for juvenile salmonids.

Pool quality and quantity, riparian shading, and instream cover are habitat concerns. The creek passes through several culverts that block fish passage and are detrimental to instream habitat. Construction of Capitol Lake restricted salmonid access to the creek, and limited estuarine functions and chum salmon populations. Removal of all culverts that block fish passage is underway and will be complete within the next few years.

Table A-1 summarizes University of Washington data on in-stream physical characteristics of the stream segments studied, including gradient, bank stability, large woody debris, and pools and riffles.

Two medium-sized habitat units along the Burlington Northern right of way within the downstream Percival Creek corridor have been identified by the City of Olympia as significant wildlife habitat (Shapiro 1994).

D-12 Water quality Percival Creek has been given a Class A water quality designation by the Washington Department of Ecology. Water quality is typically rated "fair" to "good" based on monitoring results by Thurston County Environmental Health Department.

Fair to good water quality ratings in most of the stream indicates that problems are related to storm flows and stormwater runoff, rather than chronic pollution inputs or low-flow condition problems. Some problems stem from BlackLake/Black Lake Drainage Ditch system and construction-related sediments.

Washington State standards are met for dissolved oxygen, temperature and other conventional water quality parameters. Moderately high levels of phosphorus in the creek are probably associated with stream size and periods of high turbidity, rather than pollution. Elevated levels of copper, lead, zinc, and one instance of total petroleum hydrocarbons have been noted in the creek, probably resulting from stormwater-related contaminants.

Aquatic Biota Benthic Macro-Invertebrates Benthic Index of Biotic Integrity (B-IBI) data indicate overall population abundance is moderately good, although macroinvertebrate communities show some impacts from degraded basin conditions. A single sample by Thurston County Environmental Health Department on September 16, 1998 had a B-IBI rating of 14 (low biological integrity), as shown in Table A-3.

Fish Percival Creek supports spawning runs of coho, chum, fall chinook, coastal cutthroat, and winter steelhead trout, but at reduced numbers from historic conditions. The chinook are strays from the WDF Deschutes River hatchery, since access to the creek is regulated. The numbers of fish the creek can support is not known. Use of Percival Creek by various species is summarized below:

Chinook salmon. Utilization of the creek is limited due to screening of the mouth of the creek by the hatchery. Adult spawners that aren’t harvested for eggs are allowed up Percival Creek and the Deschutes River in September for natural spawning. Juvenile salmon from the hatchery are nurtured in Percival Cove and released to Budd Inlet. Adult chinook are excluded from Percival Cove during July and August to prevent fish mortality from excessive water temperatures.

Coho salmon. Were originally present, and hatchery fish have also been released to the creek. Returning coho are released upstream of the exclusion structure in Percival Cove. Spawning occurs in the lower and middle sections of the creek. Juvenile fish will rear in freshwater for one year.

Chum salmon. Were historically present, but construction of Capitol Lake and urbanization of the lower creek estuary at Budd Inlet have limited chum spawning and rearing habitat. Chum do return to spawn in small numbers.

Winter steelhead. Return to spawn in lower and middle sections. Juveniles will rear in freshwater for at least one year. Steelhead stock is managed to provide a harvest fishery.

D-13 Cutthroat trout. Population status in Percival Creek is unknown, but they spawn in similar size and gradient streams in South Puget Sound.

Resident fish. Species include sculpin, dace, and lamprey. Resident cutthroat or rainbow trout may be present, but population status and trends are unknown.

D-14 Ellis Creek The Ellis Creek basin is characterized by rolling hills and a rural landscape; it contains Setchfield Lake and many wetlands. The highest elevation is 170 feet above sea level.

Ellis Creek headwaters are near 36th Avenue NE and flows southwesterly in a series of ditched and natural channels to the confluence with the two main tributaries, which enter the mainstem from the north and south just east of Gull Harbor Road. The creek then follows a steep gully down to Budd Inlet at Ellis Cove, within Priest Point Park.

Creek Length: 1.1 miles (mainstem) Stream Order: 1 Basin Size: 1,667 acres

Information on the basin relevant to evaluation of aquatic habitat conditions is summarized below. For details, see the Basin Reconnaissance and Public Involvement Report (Olympia 1993), particularly sections on land cover and use, hydrology, creek corridor, in-stream characteristics, water quality, and fish and wildlife.

Basin Conditions Level of urbanization Most of the Ellis Creek basin is in unincorporated Thurston County and is rural residential. The southern portion, which includes most of Priest Point Park, is within the City of Olympia. Most of the basin is outside the urban growth area and is zoned rural residential; the remainder is zoned for suburban residential development. Major new development is occurring in the watershed.

Hydrology About 5-10% of the basin is impervious surface. The wetlands associated with tributaries at the headwaters and downstream are intact and there are few if any flooding problems. New developments will have onsite stormwater management facilities; however, full development of the basin could appreciably impact flood volumes.

Riparian Corridor Where the creek has been channelized, most of the native riparian vegetation has been removed. In its undisturbed upstream reaches, and within Priest Point Park, the creek has dense riparian vegetation and fairly stable banks. Large portions of the riparian and upland areas remain undeveloped and beneficial to wildlife. There are four road crossings.

In-Stream and Wetland Habitat Conditions Physical Overall habitat conditions are fair to good. The creek provides good salmon spawning habitat, but lacks juvenile rearing habitat. The stream bed appears to be changing from predominantly gravel to fine sand and silt. Downstream of a culvert at 33rd Avenue, instream habitat is of moderate quality. Farther downstream, several areas of the creek have good instream habitat. At its mouth, the creek is piped and carried under Boston Harbor Road into Ellis Cove. This culvert is a barrier to fish passage and is expected to be improved in the near future.

Information on wetland habitat conditions is not available.

D-15

Water quality Ellis Creek has been given a Class A water quality designation by the Washington Department of Ecology. Water quality is typically rated "fair" to "good" based on monitoring results by Thurston County Environmental Health Department.

Ellis Creek has been identified as a source of surface water contamination to Budd Inlet. Bacterial contamination in the creek intermittently exceeds state requirements. Septic systems are the primary form of wastewater treatment in the basin.

The relatively low level of development and vehicular traffic in the basin suggests that priority pollutant contamination from typical urban nonpoint sources may not be an appreciable problem.

Aquatic Biota Benthic Macro-Invertebrates No data is available on invertebrate indicator species in Ellis Creek.

Fish Past investigations do not specify which fish species are found in the creek. However, use by chum salmon could be expected if the culvert at the creek's mouth is replaced or retrofitted. Chum have been observed congregating at the outlet of the pipe.

D-16 Chambers Creek/Ward Lake/Hewitt Lake This basin includes the drainage of Chambers Lake into Chambers Creek and into the Deschutes River, and separate drainages into two adjacent lakes, Ward Lake and Hewitt Lake. The highest elevations vary from about 200 feet around the lakes and 190 feet. Elevation drops to 130 feet towards the mouth where the creek enters the Deschutes River. The basin is moderately sloped with frequent rolling terraces and occasional small glacial depressions or kettles. These often contain lakes which are groundwater fed and have no surface inlets or outlets. Chambers Lake is the exception with Chambers Ditch originating at the south portion of Little Chambers Lake. Hewitt Lake is a 32-acre pothole lake with a drainage area of 301 acres. Ward Lake is a 62-acre pothole lake with a drainage area of about 313 acres. Smith Lake is a 12-acre, groundwater-fed lake with no outlet.

Chambers drainage ditch is a seasonal channel that was ditched through most of is length early in the century; it flows from Chambers Lake south to its confluence with Chambers Creek and the South Tributary upstream of Rich Road. Chambers Creek is a natural stream with year-round flow through most of its length. The South Tributary is a network of natural channels, artificial ditches, and poorly defined wetlands, which flows intermittently and remains dry through most of the year.

Creek Length: 4.15 (creek and ditch); tributary 3.6 miles Stream Order: 2 Basin Size: 8,400 acres

Information on the basin relevant to evaluation of aquatic habitat conditions is summarized below. For details, see the Chambers/Ward/Hewitt Comprehensive Drainage Basin Plan (Thurston County 1995), particularly sections on land use, hydrology, water quality, and fish and wildlife habitat.

Basin Conditions Level of urbanization The basin is 13.2 square miles, and encompasses urban portions of east Olympia (including the rapidly developing southeast Olympia area), Lacey, and developing areas of Thurston County. Chambers Lake is in Olympia and Lacey; Ward Lake is in Olympia and Thurston County; Hewitt Lake is entirely within the County's jurisdiction.

Land use is primarily suburban residential and rural; the central and northern portions are moderately to heavily urbanized. Rural areas are increasingly being converted to single-family and multifamily residential uses. Nine percent of the basin has been developed with substantial new commercial and high-density residential areas. High residential and commercial growth is occurring due to the basin's location on the edge of the Urban Growth Area. Only the southern portion of the basin has minimal development.

Hydrology Impervious surfaces cover about 6% of the basin. Approximately 28% of the developed area in the basin has no stormwater management facilities, and much of the remainder provides inadequate stormwater management. Many of the natural and man-made conveyance and storage systems in the basin are at or near capacity.

D-17 Some historic wetlands have been filled for development, altering the basin hydrology. However, the basin still contains extensive wetlands – approximately 902 acres or 10.8% of the basin – which detain flood waters. Numerous other wetlands are present throughout the southern portion of the basin. Some wetlands maintain a high degree of biological integrity, and several have been designated as significant habitat (Shapiro, 1994).

Riparian Corridor Some of the Chambers Creek riparian zone is densely vegetated with streamside species such as black cottonwood, Douglas-fir, red alder, western red cedar, and shrubs. East of Rich Road there is little vegetative cover. In the flat prairie areas, the riparian zone is a wide flood plain vegetated with wetland shrubs and emergent species such as sedges and rushes; agriculture has replaced native vegetation in much of this area. Chambers Creek is extensively ditched and developed to sides of ditch. Eight roads cross Chambers Creek and Chambers Ditch.

Considerable lakeside residential development has eliminated portions of the Hewitt and Ward Lake buffers.

In-Stream and Wetland Habitat Conditions Physical Overall habitat conditions are considered poor. Chambers Creek offers three types of coho habitat: a few spawning sites near the mouth, year round rearing habitat below Rich Road, and limited winter rearing habitat between the springs below Rich Road to a point below Yelm Highway. The lower quarter mile of the South Tributary offers viable seasonal habitat for migrating fish, with fair overhanging cover and in-stream woody debris.

Upstream of Yelm Highway, habitat is minimal. Chambers Ditch provides some rearing habitat when it is flowing, as does the wetland below 60th Loop SE; but does not contain enough pools, riparian vegetation, or cover to offer good habitat.

Chambers Lake habitat is best suited for warm water fish; large areas of aquatic vegetation provide refuge. The lake has been blocked to anadromous species for several years by screens that hold in the grass carp, which were planted in an attempt to control weed growth. Ward Lake and Hewitt Lake habitat is generally good; the south and west shores of Ward Lake contain native lakeshore vegetation, which is critical for fish habitat.

The City of Olympia wildlife study (Shapiro,1994), found that the area west of Chambers Lake and undeveloped land between Ward and Chambers Lake constitute the largest remaining blocks of Category I (best) wildlife habitat in southwestern Olympia. Chambers Lake wetland areas contain some unique vegetation communities. The northwest arm of Chambers Lake is a bog dominated by spaghum moss and buck bean at the center, surrounded by a perimeter of Labrador tea. Upland forests provide habitat for numerous wildlife species and act as a substantial buffer for the wetlands. The study recommended protecting seven medium-sized habitat units in Olympia's long-term growth area; four of them lie completely within the Chambers Basin. The largest is the area west of Chambers Lake; two others lie further west of the lake, and the area south of Hewitt Lake recommended for inclusion is "the only medium-sized unit with any connection to substantial wildlife habitat outside the UGMA." (Shapiro, 1994).

Water quality

D-18 Chambers Creek has been given a Class A water quality designation by the Washington Department of Ecology. Water quality is typically rated "fair" to "good" based on monitoring results by Thurston County Environmental Health Department.

Fecal coliform contamination is present throughout the creek system, and nitrate levels have been high at the mouth and tributary. Other non-point problems include erosion from stormwater outfalls, heavy metals in stormwater and lake sediments, and algae blooms in the lake from nutrients.

Monitoring result show water quality in Chambers Lake as poor to fair, Hewitt and Ward Lakes as good. Low levels of dissolved nitrate and nitrite, organic nitrogen, and phosphorous have been detected in Ward Lake.

Aquatic Biota Benthic Macro-Invertebrates No data is available on invertebrate indicator species in Chambers Creek or the lakes.

Fish There were no salmon or sea-run cutthroat trout in Chambers Creek or the Deschutes River before development of a fish ladder at Deschutes Falls, but there were trout throughout the area. The basin now contains both anadromous and resident fish species.

Coho salmon and sea-run cutthroat trout make limited use of Chambers Creek. A few spawning sites are located near the creek’s mouth and year-round rearing habitat in the lower reaches. Low gradient segments with few riffles are too slow for spawning, but serve as rearing areas for coho, coastal cutthroat, and winter steelhead. Resident fish species in Chambers Creek include sculpin, dace, and lamphrey, primarily bottom dwellers.

Historically, cutthroat trout, bass, perch, catfish, crappie, and spiny ray inhabited Chambers and Little Chambers Lakes. Cutthroat have mostly disappeared. The Department of Fish and Wildlife manages the lake primarily for warm water species, though they occasionally plant cutthroat.

The Department of Fish and Wildlife plants rainbow trout and kokanee annually in Ward Lake. Stickleback, a native fish in Ward Lake, have not been seen in 15 years. DFW plants cutthroat trout in Hewitt Lake every two or three years, and occasionally salmon. Both lakes contain large-mouth bass.

D-19 Mission Creek The Mission Creek basin lies along the ridge above East Bay. Most of the basin is relatively flat at about 180 feet elevation.

Mission Creek originates in a small section of wetland between Pine and Yew Avenues and flows northwesterly through a wetland area and residential neighborhoods around Miller Street. West of Bethel Street, the creek flows through a steep wooded ravine with moderately unstable slopes before crossing East Bay Drive and entering Budd Inlet at the southern boundary of Priest Point Park.

Creek Length: 1.5 miles. Stream Order: 1 Basin Size: 360 acres

Information on the basin relevant to evaluation of aquatic habitat conditions is summarized below. For details, see the Basin Reconnaissance and Public Involvement Report (Olympia 1993), particularly sections on land cover and use, hydrology, creek corridor, in-stream characteristics, water quality, and fish and wildlife.

Basin Conditions Level of urbanization The basin is almost entirely within Olympia’s city limits except for southeastern tip east of Fairview and Edison Streets in unincorporated Thurston County. Land use is primarily single family residential and duplex units, except for about 300 acres of Priest Point Park, a large wetland upstream of Ethridge Street, and undeveloped land, including wetlands.

Hydrology There is only one onsite stormwater treatment and storage facility in the basin, resulting in substantially increased peak flows associated with stormwater runoff.

The basin’s wetlands store runoff during high flows and moderate high flow impacts to the creek system. Flooding of developed property is not occurring.

Riparian Corridor In Priest Point Park and upstream to Bethel St. the riparian corridor is characterized by healthy forest vegetation creating good shading levels. Riparian buffers elsewhere are minimal. There are five road crossings including a major culvert at East Bay Drive.

In-Stream and Wetland Habitat Conditions Physical Overall habitat conditions are poor. From the headwaters to Miller, wetland areas, the creek channel is largely undefined, offering poor habitat. The intermittent flow and undefined channel above Ethridge Street does not offer sufficient habitat diversity or flow for anadromous fish.

Downstream of Miller, stream banks generally stable, ditched in several places. Upstream of Bethel Street there is little habitat diversity; the creek has a low gradient, with some gravels in intermittent reaches.

D-20 Downstream of Bethel Street, habitat diversity improves dramatically; large woody debris creates pools. Farther downstream the channel becomes braided and the substrate is predominately loose gravels. The banks are eroding in places.

No information is available on wetland habitat conditions.

Water quality Mission Creek has been given a Class A water quality designation by the Washington Department of Ecology. Water quality is typically rated "poor" based on monitoring results by Thurston County Environmental Health Department. A poor rating indicates samples routinely fail water quality standards. Monitoring results in 1996-97 were good, although serious bacterial contamination has been present throughout the creek in previous years. Nutrient levels, particularly nitrates, were elevated.

Only about half the basin is served by both sanitary sewers and stormwater conveyance systems. The creek has been identified as a major source of bacterial surface water contamination in Budd Inlet. Fecal coliform concentrations in the creek and stormwater have been consistently above state threshold criteria. One source of the bacterial contamination may be septic tanks in the basin that are prone to failure during saturated soil conditions.

Aquatic Biota Benthic Macro-Invertebrates No information is available on invertebrate indicator species.

Fish The Washington Department of Fish and Wildlife has identified Mission Creek from its mouth to Miller Street as a fishbearing stream, although the fish species in the creek are not identified. Occasional salmon and trout use is possible.

D-21 Schneider Creek The Schneider Creek Basin lies along a relatively flat ridge to the west of Budd Inlet. Schneider Creek originates in an urban residential neighborhood south of Capital Mall Drive. It flows underground from east of Capital Mall, beneath the Harrison/Division Street commercial area, and surfaces in the moderate density residential neighborhoods west and east of Division. It flows northerly past Groves Avenue, then turns east and flows through a deep-cut ravine to discharge to Budd Inlet via a culvert under West Bay Drive. Three small tributaries enter the downstream portion of the creek.

Creek Length: 1.25 miles Stream Order: 1 Basin Size: 662 acres

Information on the basin relevant to evaluation of aquatic habitat conditions is summarized below. For details, see the Basin Reconnaissance and Public Involvement Report (Olympia 1993), particularly sections on land cover and use, hydrology, creek corridor, in-stream characteristics, water quality, and fish and wildlife.

Basin Conditions Level of urbanization The 662-acre Schneider Creek basin is located within Olympia’s city limits, except for its northern tip. Land use is dominated by single-family and duplex units, commercial and industrial developments, and undeveloped lands.

Hydrology About 30-33% of the basin is covered with impervious surfaces. Natural storage has been lost by filling in the headwaters and other historical wetlands, and piping the upper half of the creek. The highly developed land use, along with inadequate on-site stormwater treatment and storage facilities, has created flooding problems in the creek system. Several upland and streamside developments are threatened by flooding. No undeveloped sites are available for construction of stormwater management facilities. One of the tributaries has been piped to remove sediment loading to the creek mainstem. Downcutting throughout the creek is extreme.

Riparian Corridor In the unpiped downstream half of the basin, the riparian zone is largely protected by wooded areas that help protect the sensitive upper stream banks from potential failures. The steep canyon walls also help buffer the creek, but are highly erosive.

In-Stream and Wetland Habitat Conditions Physical Overall instream conditions in Schneider Creek are poor to fair. The downstream reaches have year-round flow, due to the strong summer groundwater flow to creek. There, the creek system provides beneficial but very limited spawning and rearing habitat for salmon, including a healthy amount of large woody debris, pools, and habitat diversity.

However, upstream spawning habitat has been destroyed by undergrounding the stream. Overall, the physical and biological integrity of the creek system has been degraded by excessive stormwater runoff that prompts massive bank failures, undermines trees, and chokes the creek

D-22 with sediment. Mass erosion is common in the mainstem and tributaries of the creek. Degradation from high stormwater flows is most severe in the creek’s three tributaries. The creek bottom is severely scoured, with a highly mobile, unstable substrate. There are two road crossings; the culvert at the mouth of the creek is a partial barrier to fish.

Water quality Schneider Creek has been given a Class A water quality designation by the Washington Department of Ecology. Water quality is typically rated "poor" to "good" based on monitoring results by Thurston County Environmental Health Department. Good ratings are from samples taken in areas not impacted by stormwater. Samples taken in 1996-97 met water quality standards; however in the past occasional samples have had high fecal coliform bactera levels.

The extensive road network and high level of commercial and residential development in the basin supports the likelihood of elevated contaminant levels. The vast majority of the basin is served by sanitary sewer systems. Developments in the basin have very little onsite stormwater treatment. Stormwater runoff discharging to the creek from the conveyance system serving the southern portion of the basin indicates a high level of contamination. Vehicular traffic in the basin generates high levels of contaminated stormwater. Primary contaminants are suspected to be priority pollutants from vehicles, sediments, and possibly nutrients.

Aquatic Biota Benthic Macro-Invertebrates Analysis of a October 1998 sampling of benthic invertebrates by Thurston Couny Health Department gave a score of 24 on the Benthic Invertebrate Index of Biological Integrity (BIBI). Scores of 0-24 indicate low biological integrity, based on comparison with relatively unimpacted Puget Sound Lowland and Willamette Valley streams. See Table A-3.

Fish This creek has limited use by coho salmon. Use of this habitat by other species, such as resident trout, is unknown.

D-23 Indian-Moxlie Creek The Indian-Moxlie Creek basin is characterized by rolling terraces and numerous small depressions. Many year round and seasonal tributaries, springs, and seeps enter the two main creeks.

Indian Creek originates in Bigelow Lake, a spaghum bog and flows south in an unmaintained and heavily vegetated drainage ditch for about one mile across a wide flood plain with extensive streamside wetlands. Downstream, the creek is piped under several arterial roads, an industrial site, and Interstate 5 (I-5). On the south side of I-5, the creek flows in a partially channelized and piped corridor that parallels the abandoned Burlington-Northern Railroad grade. The creek is then piped back under I-5 and joins Moxlie Creek near the intersection of Plum Street and Union Avenue in Olympia's central business District. Indian Creek's drainage area includes the Bigelow Lake open wetland peat bog, several extensive but highly degraded wetlands, two small lakes, and a major tributary.

Moxlie Creek originates at an artesian spring in Olympia's Watershed Park and flows northerly through the heavily forested and undeveloped park for about one mile before being piped under I-5. Downstream of I-5, the creek enters high-density commercial and industrial areas before the two creeks are combined and piped 3,200 feet under Olympia’s central business district into the eastern portion of Budd Inlet. Moxlie Creek is composed of a main stem and many small springs and tributaries.

Creek Length: Indian Creek: 3 miles (14% underground); Moxlie Creek: approximately 1.8 miles (36% underground) Stream Order: 1 Basin Size: Indian: 1,459 acres; Moxlie: 1,391 acres (Total: 2,850)

Information on the basin relevant to evaluation of aquatic habitat conditions is summarized below. For details, see the Indian-Moxlie Creek Comprehensive Drainage Basin Plan (Olympia 1993), particularly sections on land cover and use, hydrology, corridor characteristics, geomorphology, sediment and bedload, fish and wildlife.

Basin Conditions Level of urbanization The basin is highly developed, except for the headwaters in Bigelow Lake and Watershed Park. Together Indian/Moxlie Creek basin covers 4.5 square miles and includes a portion of downtown Olympia and established older residential and commercial neighborhoods on the east side of Olympia. The basins are experiencing slower growth than many nearby, lesser-developed basins because to a large extent they already developed. The northern portion of Indian Creek basin includes semi-rural, but developing areas of Thurston County outside the city limits.

Hydrology About 34% of the basin is covered by impervious surfaces. Increased runoff and channelized, piped, and filled creek systems have reduced the creeks’ natural ability to detain floods. Over 90% of non-residential developments in the basin provide no stormwater storage/treatment, and no feasible sites are available for effective retrofit.

D-24 Creek flooding has created eroded streambanks, increased sediment transport and deposition, widened the creek, and reduced meanders, pool spacing, and LOD levels to 20-50% less than under natural conditions. Given near build-out land use conditions in the basin, creek flows are not expected to increase substantially.

Flows in Moxlie Creek during low and moderate flow conditions are higher than in Indian Creek. Flood flows in Moxlie Creek are augmented by I-5 discharges and a large stormwater outfall at its headwaters.

Historic wetlands and estuaries have been filled and the few remaining wetlands have been affected by development. Wetland hydrology has been altered by stormwater discharges. Urbanization is encroaching on the few remaining high-quality wetlands. Development around Bigelow Lake could degrade high-quality, biologically productive wetlands. Although impacted biologically, remaining wetlands still offer important flood flow storage.

Riparian Corridor The riparian zone in the upper reaches of Indian Creek is densely vegetated with patches of wetland species and other water-tolerant plants. Lower reaches of the creek, along the abandoned railroad grade, are bordered by common riparian plants such as willow, red alder, and shrubs, as well as large coniferous trees. The riparian corridor between Eastside Street and Boulevard Road encompasses about 100 acres.

In the upper reaches of Moxlie Creek, within the 171-acre Watershed Park, the creek is buffered by a densely wooded corridor with large coniferous trees and shrubby undergrowth, flowing in part through a deeply incised canyon. Boardwalks in the park protect wetland areas and creek crossings. North of I-5 the unpiped creek channel has streamside vegetation ranging from insufficient herbaceous growth to thin strips of red alder and willow. This vegetation offers poor protective cover and woody debris to the creek.

In-Stream and Wetland Habitat Conditions Physical Upstream of their confluence, about 4500 feet of Indian and 950 feet of Moxlie have been piped. Creek segments have been channelized and ditched to increase drainage and reroute flows. The 25 stormwater outfalls contribute excessive runoff to the creeks and generate erosion problems. Sediment clogs creek substrate.

The gradient and velocity in middle reaches of Indian Creek are typically moderate, suitable for salmon spawning. However, culverts and pipes generate water velocities in excess of Department. of Fish and Wildlife fish passage guidelines. Roads cross the two streams in about 16 locations; most of the associated culverts are barriers to fish passage.

Spawning areas are limited in Moxlie Creek due to the primarily silty substrate. The unpiped section of the creek outside the park has poor habitat diversity, poor protective cover, and low woody debris levels.

Bigelow Lake and surrounding wetlands were designated as Category I (best) habitat in Olympia's wildlife habitat study (Shapiro,1994). Bigelow Lake is an open water habitat with adjacent scrub-shrub wetlands providing habitat for breeding populations of wood duck and

D-25 Cooper's hawk. The wetland contains large bog areas and associated plant communities composed of Labrador tea, bog laurel, and sphagnum moss as well as scrub-shrub species.

Water quality Indian and Moxlie Creeks are classified as Washington State Class A streams, indicating they should exhibit excellent water quality. However, water quality is typically rated "poor" based on monitoring results by Thurston County Environmental Health Department. Conventional pollutants commonly exceed state standards in both creeks. Fecal coliform concentrations are consistently high, and the Indian-Moxlie Creek system has been identified as a source of fecal coliform bacteria contamination to Budd Inlet.

Stormwater discharges to the creeks create high flood flows and contribute nonpoint pollutants. Sources include: discharges from septic systems, improper waste management, erosion, small agricultural operations, vehicular traffic and industrial practices. Elevated nitrogen and phosphate levels may prompt excessive biological productivity in the creeks. Elevated levels of trace organic compounds and metals also have been found in creek waters and sediments.

Aquatic Biota Benthic Macro-Invertebrates No information is available on invertebrate species in Indian or Moxlie Creeks.

Fish Although use is limited, both creeks have historically supported anadromous fish. Chum, sea-run cutthroat, coho, chinook, and steelhead all historically migrated to Indian Creek. The fall chinook are likely strays from the WDF Deschutes River Hatchery. WDF plants coho in Indian Creek near the Boulevard Street bridge.

The 230-foot open channel west of the confluence of Indian and Moxlie Creeks has been the main spawning habitat for coho and chinook in Indian Creek. The extensive pipe system has prevented migration further upstream. In 1992 the creek was re-routed around the intersection of Plum Street and Union Avenue in an open channel to allow fish passage further upstream. In recent years, salmon of unknown species have been observed in Indian Creek immediately upstream of the confluence with Moxlie Creek, but salmon use and/or spawning has not been documented further upstream.

According to WDF records, coho, chinook, and steelhead spawn in Moxlie Creek, primarily in the upstream creek segments within Watershed Park.

Resident fish are found in the entire length of Indian Creek. Species include coastal cutthroat, cottids, and three-spined stickleback. Information on the population status and trends of resident fish in Moxlie Creek is not available.

D-26

Table 3.2 Summary of Olympia Creek Basin and In-stream Conditions

Green Cove Creek Basin and Riparian Conditions In-stream and Wetland Habitat Conditions Aquatic Biota

Riparian Level of Urbanization Hydrology Physical Conditions Water Quality* Corridor

• 24 percent • Approximately • Good creek • Overall condition: • Monitoring results: • B-IBI = 30 developed. 12 percent and good to excellent good water quality. (moderate - impervious wetland habitat diversity. Thurston • No significant water surfaces. buffers County • Stormwater and quality problems. with Health Dept. • Most urbanization have beneficial • Potential 10/1/98). moderate- and not significantly tree construction-related high-density degraded creek • B-IBI (from species. sediments are a developments and wetland UW???) threat to creek and have on-site • Four road habitats. wetland inhabitants. • Healthy runs stormwater crossings. • High potential for of Coho and treatment and continued good Chum. storage Chum and Coho facilities. • Commercial spawning habitat. shellfish • Given soil • Fairly abundant harvesting in types in the high quality Eld Inlet. basin, new summer rearing developments habitat for Coho would increase salmon. stormwater discharges to • Excellent wetland the creeks and habitat at Grass wetlands. Lake Refuge. • Extensive wetland systems help buffer the creek from peak flows. *Based on Thurston County’s Annual Water Resources Monitoring Reports (1992-97), using state water quality standards for fecal coliform, dissolved oxygen, temperature, pH, turbidity, and toxicity. “Good” – Usually meets water quality standards; or violates only one part of the two-part fecal coliform standard; or the violation is most likely the result of natural conditions rather than pollution. “Fair” – Frequently fails one or more water quality standards; other parameters, such as nutrients, indicate water quality is being impacted by pollution. “Poor” – Routinely fails water quality standards by a large margin; other parameters, such as nutrients, are at elevated concentrations.

D-27

Table 3.2 (continued) Summary of Olympia Creek Basin and In-Stream Conditions

Woodard Creek Basin and Riparian Conditions In-stream and Wetland Habitat Conditions Aquatic Biota

Riparian Level of Urbanization Hydrology Physical Conditions Water Quality* Corridor

• Moderate to high • 15 to 20 • Poor • Overall: fair to • Monitoring results: • B-IBI = 36 development. percent buffers in good. fair. (moderate - impervious. some areas; Thurston • Moderately high • Fish barrier at 36th • Class AA water other areas County development in • Extensive Avenue. quality standards very good. Health Dept. headwater areas. wetland apply to the creek. • Some good 10/1/98). systems help • Six road spawning and detain flood crossings. • Chum, Coho, rearing habitat. flows. Chinook, • Urbanization and Steelhead, stormwater have and Sea-run degraded habitat Cutthroat. conditions. • Some level of • Good wetland fish use habitat conditions. throughout the creek. • Annual planting of Coho. • Commercial shellfish harvesting in Henderson Inlet. *Based on Thurston County’s Annual Water Resources Monitoring Reports (1992-97), using state water quality standards for fecal coliform, dissolved oxygen, temperature, pH, turbidity, and toxicity. “Good” – Usually meets water quality standards; or violates only one part of the two-part fecal coliform standard; or the violation is most likely the result of natural conditions rather than pollution. “Fair” – Frequently fails one or more water quality standards; other parameters, such as nutrients, indicate water quality is being impacted by pollution. “Poor” – Routinely fails water quality standards by a large margin; other parameters, such as nutrients, are at elevated concentrations.

D-28

Table 3.2 (continued) Summary of Olympia Creek Basin and In-Stream Conditions

In-stream and Wetland Habitat Percival Creek Basin and Riparian Conditions Aquatic Biota Conditions

Riparian Level of Urbanization Hydrology Physical Conditions Water Quality* Corridor

• 50 percent of the • 20 to 25 • Large • Overall condition: • Monitoring results: • Biological basin is developed. percent of the contiguous fair to good. good water quality. index of basin is buffers quality: • High-density land • High-quality • Creek typically impervious along moderate. uses expected to rearing and meets state water surface. downstream increase. spawning habitat quality standards. • B-IBI = 14 portions of • Urbanization in Black Lake (low – the creek; • Construction- has Drainage Ditch. Thurston 62.6 percent related sediments substantially County of buffer • Construction of are a threat to creek increased creek Health Dept. undeveloped Capitol Lake and wetlands. flows. 9/16/98 at (UW). limits spawning • Some water quality footbridge). • Numerous on- and rearing • 51.5 percent problems stem site and habitat. • Coho. of corridor > from Black regional 100 feet (30 • Removal of all Lake/Black Lake • Fall Chinook. stormwater meters) fish barrier Drainage Ditch storage • Winter (UW). culverts system. facilities. steelhead. underway. • Gradual loss • Extensive • of beneficial Sea-run wetlands on tree species cutthroat. Percival Creek in the and Black • buffers. Chum. Lake Ditch moderate flood • Degraded by flow. urbanization in some upstream areas. • Eight road crossings; no crossings in the down- stream portion of the creek. *Based on Thurston County’s Annual Water Resources Monitoring Reports (1992-97), using state water quality standards for fecal coliform, dissolved oxygen, temperature, pH, turbidity, and toxicity. “Good” – Usually meets water quality standards; or violates only one part of the two-part fecal coliform standard; or the violation is most likely the result of natural conditions rather than pollution. “Fair” – Frequently fails one or more water quality standards; other parameters, such as nutrients, indicate water quality is being impacted by pollution. “Poor” – Routinely fails water quality standards by a large margin; other parameters, such as nutrients, are at elevated concentrations.

D-29

Table 3.2 (continued) Summary of Olympia Creek Basin and In-Stream Conditions

In-stream and Wetland Habitat Ellis Creek Basin and Riparian Conditions Aquatic Biota Conditions

Riparian Level of Urbanization Hydrology Physical Conditions Water Quality* Corridor

• Mostly rural and • 5 to 10 percent • Good • Overall condition: • Monitoring results: • Benthic levels single-family land impervious buffers, fair to good; fair to good. unknown. use. surfaces. especially downstream is within Priest moderate to good. • Use by Chum • New Point Park. salmon developments • Several fish expected, if will have on- barrier culverts • Four road the culvert at site stormwater are present, crossings. the creek’s management including one at mouth is facilities. the creek’s mouth. replaced or • Wetlands are retrofitted. intact. *Based on Thurston County’s Annual Water Resources Monitoring Reports (1992-97), using state water quality standards for fecal coliform, dissolved oxygen, temperature, pH, turbidity, and toxicity. “Good” – Usually meets water quality standards; or violates only one part of the two-part fecal coliform standard; or the violation is most likely the result of natural conditions rather than pollution. “Fair” – Frequently fails one or more water quality standards; other parameters, such as nutrients, indicate water quality is being impacted by pollution. “Poor” – Routinely fails water quality standards by a large margin; other parameters, such as nutrients, are at elevated concentrations.

D-30

Table 3.2 (continued) Summary of Olympia Creek Basin and In-Stream Conditions

Chambers Creek/ In-stream and Wetland Habitat Ward Lake/ Basin and Riparian Conditions Aquatic Biota Conditions Hewitt Lake

Riparian Level of Urbanization Hydrology Physical Conditions Water Quality* Corridor

• Primarily suburban • Approximately • Extensively • Overall condition: • Monitoring results: • Benthic levels residential and 6 percent ditched and poor. fair to good water unknown. rural land uses. impervious developed to quality in creek. • Type 3 water body surfaces. sides of • Limited use (least valuable • Chambers Lake: ditch. by Coho and • Most of the creek system used poor to fair. Sea-run creek is a • Good by fish). • Hewitt and Ward cutthroat. seasonal ditch. riparian • Limited spawning Lakes: good. corridor in • Extensive sites and rearing downstream wetland habitat in lower sections. systems detain reaches of the floodwaters. • Considerable creek only. lakeside • Minimal habitat residential upstream of the development Yelm Highway. eliminates portions of • High-quality Hewitt and wetland habitat on Ward Lake the east side of buffers. Chambers Lake. • Eight road • Open water crossings. habitat provided by Ward and Hewitt Lakes. *Based on Thurston County’s Annual Water Resources Monitoring Reports (1992-97), using state water quality standards for fecal coliform, dissolved oxygen, temperature, pH, turbidity, and toxicity. “Good” – Usually meets water quality standards; or violates only one part of the two-part fecal coliform standard; or the violation is most likely the result of natural conditions rather than pollution. “Fair” – Frequently fails one or more water quality standards; other parameters, such as nutrients, indicate water quality is being impacted by pollution. “Poor” – Routinely fails water quality standards by a large margin; other parameters, such as nutrients, are at elevated concentrations.

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Table 3.2 (continued) Summary of Olympia Creek Basin and In-Stream Conditions

In-stream and Wetland Habitat Mission Creek Basin and Riparian Conditions Aquatic Biota Conditions

Riparian Level of Urbanization Hydrology Physical Conditions Water Quality* Corridor

• Largely developed • 20 to 25 • Good • Overall condition: • Monitoring results: • Benthic levels basin. percent buffers in poor. poor water quality. unknown. impervious. Priest Point • Fish-bearing • Fecal coliform Park and • Occasional • Inadequate on- stream, but exceeds state upstream to salmon/trout site and/or insufficient flow standards. Bethel use possible. regional and diversity for Street; stormwater anadromous fish. minimal treatment and buffers • Sandy creek storage elsewhere. substrate not facilities. supportive of • Low-quality • Substantially high-quality wetland increased peak biological conditions. flows communities. associated with • Five road stormwater crossings. runoff. • Some wetlands are intact and store runoff. *Based on Thurston County’s Annual Water Resources Monitoring Reports (1992-97), using state water quality standards for fecal coliform, dissolved oxygen, temperature, pH, turbidity, and toxicity. “Good” – Usually meets water quality standards; or violates only one part of the two-part fecal coliform standard; or the violation is most likely the result of natural conditions rather than pollution. “Fair” – Frequently fails one or more water quality standards; other parameters, such as nutrients, indicate water quality is being impacted by pollution. “Poor” – Routinely fails water quality standards by a large margin; other parameters, such as nutrients, are at elevated concentrations.

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Table 3.2 (continued) Summary of Olympia Creek Basin and In-Stream Conditions

In-stream and Wetland Habitat Schneider Creek Basin and Riparian Conditions Aquatic Biota Conditions

Riparian Level of Urbanization Hydrology Physical Conditions Water Quality* Corridor

• Highly developed • 30 to 33 • Good buffer • Overall condition: • Monitoring results: • B-IBI = 24 commercial and percent in poor to fair. poor to good. (low – residential basin. impervious downstream Thurston • Healthy LWD, • Minimal surface. sections. County pools, and stormwater Health • Upstream half • Steep diversity treatment. 10/9/98). of creek canyon walls downstream. • High contaminant completely help buffer • B-IBI = (from • Highly unstable, loading associated underground. the creek. UW???) mobile substrate with stormwater • Inadequate on- • Two road impacts creek flows. • Limited use site stormwater crossings. inhabitants. by Coho • Relatively good treatment and salmon. • Severely • Year-round flow water quality in storage scoured only in flows not impacted facilities. No creek. downstream by stormwater. feasible sites portions of the for regional • Highly creek. facilities. erosive main channel and • Strong summer • Excessive tributary groundwater stormwater- slopes. flows to the creek. related peak flows. • Historical wetlands filled. *Based on Thurston County’s Annual Water Resources Monitoring Reports (1992-97), using state water quality standards for fecal coliform, dissolved oxygen, temperature, pH, turbidity, and toxicity. “Good” – Usually meets water quality standards; or violates only one part of the two-part fecal coliform standard; or the violation is most likely the result of natural conditions rather than pollution. “Fair” – Frequently fails one or more water quality standards; other parameters, such as nutrients, indicate water quality is being impacted by pollution. “Poor” – Routinely fails water quality standards by a large margin; other parameters, such as nutrients, are at elevated concentrations.

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Table 3.2 (continued) Summary of Olympia Creek Basin and In-Stream Conditions

Indian/Moxlie In-stream and Wetland Habitat Basin and Riparian Conditions Aquatic Biota Creek Conditions

Riparian Level of Urbanization Hydrology Physical Conditions Water Quality* Corridor

• Highly developed, • 35 to 40 • Piped under • Overall: poor. • Monitoring results: • Benthic levels except for the percent downtown, poor. unknown. • Extensive piped headwaters of impervious. 4,500 feet of sections. • Contaminants • Limited use Indian Creek and Indian and • Channelized exceed state by Chum, Watershed Park. 950 feet of • Poor habitat and ditched standards. Sea-run Moxlie. diversity, poor creek with cutthroat, cover, low LWD. numerous • Watershed Coho, stormwater Park • Sandy substrate Chinook, and outfalls. provides with few Steelhead. good buffer spawning gravels • Inadequate on- • Migrating for Moxlie; does not support site and salmon not abandoned diverse in-stream regional observed in railroad habitat. stormwater recent years. grade management • (Fish do not buffers a Numerous fish facilities. No migrate portion of barrier culverts. feasible sites through piped Indian • for effective High-quality creek Creek. retrofit. wetlands at sections.) Bigelow Lake. • • Substantially ± 16 road increased peak crossings. flows. • Few remaining wetlands. *Based on Thurston County’s Annual Water Resources Monitoring Reports (1992-97), using state water quality standards for fecal coliform, dissolved oxygen, temperature, pH, turbidity, and toxicity. “Good” – Usually meets water quality standards; or violates only one part of the two-part fecal coliform standard; or the violation is most likely the result of natural conditions rather than pollution. “Fair” – Frequently fails one or more water quality standards; other parameters, such as nutrients, indicate water quality is being impacted by pollution. “Poor” – Routinely fails water quality standards by a large margin; other parameters, such as nutrients, are at elevated concentrations.

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