November 23, 1999
Mr. Peter J. Eglick, Esq.
Helsell Fetterman
1500 Puget Sound Plaza
1325 Fourth Avenue
Seattle, WA 98101
Dear Mr. Eglick:
You asked BioAnalysts, Inc., to comment on the Corps of Engineers Public Notice of Application for Permit that covers effects of constructing a new runway at Seattle-Tacoma International Airport (hereafter referred to as "Sea-Tac"). Some of those effects involve filling of wetlands totaling 18.33 acres, temporary impacts on other wetlands, fill to construct the third runway, relocation of 980 feet of Miller Creek and 1,290 feet of drainage channels in the Miller Creek Basin, and various other activities. We direct our comments primarily to effects on stream habitat and on salmonids that use streams affected by the activities proposed in the permit application.
Consultants in BioAnalysts specialize in environmental issues affecting trout and salmon populations. We investigate factors important to these species, including habitat, land uses, and harvest management, and we work on species designated as endangered or threatened (coho, steelhead, chinook salmon, and bull trout). Our comments below are the compilation of expert opinions and reviews of Dr. Donald Chapman, Dr. Tracy Hillman, Mr. John Stevenson, and Mr. Mark Miller.
Dr. Chapman has 44 years of experience as a fisheries biologist. He has researched, published, and consulted in ecological relationships between land uses and salmonids. He has worked in many streams in the Pacific Northwest, including both coastal and inland streams, which contained various salmon and trout species. During field reconnaissance for the U.S. Department of Justice as part of work on Phase 2 of the Boldt Decision, Dr. Chapman visited over one-hundred small streams in the Puget Sound area to investigate salmon habitat conditions. He has taught fisheries ecology at Oregon State University, University of Wisconsin, University of Idaho, and Montana State University. He is also experienced in assessing effects on instream flows on fish habitat. Dr. Chapman has authored more than 100 reports, many published in peer-reviewed journals and books. Dr. Chapman’s vitae is attached to this letter.
Dr. Hillman is an experienced aquatic ecologist with over 15 years experience studying the effects of land uses such as forestry, grazing, mining, and hydroelectric development on streams and fishes. He has worked in streams in Pacific Northwest streams containing various trout and salmon species. Dr. Hillman has taught at Idaho State University and Montana State University. He has authored more than 70 reports, including biological assessments and evaluations, recovery plans, and technical reports for habitat conservation plans. He has published in peer reviewed journals. Dr. Hillman has several years experience designing, implementing, and managing projects on fisheries and aquatic ecology. Dr. Hillman has surveyed most sections of Miller, Walker, and Des Moines creeks. He was lead author on a habitat and spawning survey conducted in these streams. Dr. Hillman’s vitae is attached to this letter.
Mr. Stevenson is a fisheries biologist with extensive experience studying salmon. He has a strong background in salmon passage issues and biological requirements of salmon and trout. He has written several reports that deal with salmon and trout issues. Mr. Stevenson led the field studies on Miller, Walker, and Des Moines creeks. He co-authored a report on the habitat and spawning distribution of salmon and trout in these streams. His vitae is attached to this letter.
Mr. Miller is a fisheries biologist with specialties in salmon and trout habitat requirements and species interactions. He has investigated the spawning behavior and distribution of salmon in many Pacific Northwest streams. He has also been involved with Natural Resource Damage Assessments. He has written several technical reports dealing with salmon and trout issues. Mr. Miller assisted with classifying stream-riparian habitat within Miller, Walker, and Des Moines creeks. His vitae is attached to this letter.
Among the materials that we have in hand are:
You should regard our comments as an overview of the potential effects of the activities involved in construction of the new runway. Because we are familiar with the ecological requirements of coho salmon, chinook salmon, chum salmon, and cutthroat trout and steelhead, we can offer a generic opinion on potential effects of the proposed project.
Development of a third runway at Sea-Tac will negatively affect the aquatic ecosystem within Miller, Walker, and Des Moines creeks. Each of these streams originates near the airport and flows into Puget Sound. Miller Creek originates northwest of the airport at an elevation of approximately 110 meters. Its watershed encompasses approximately 1,922 hectares. Walker Creek, the largest tributary of Miller Creek, originates from a wetland west of the airport at an elevation of approximately 90 meters. It flows toward, and then parallels Miller Creek, ultimately flowing into Miller Creek about 0.4 kilometers from Miller Beach on Puget Sound. Des Moines Creek drains an area of about 1,500 hectares near the center of the Seattle-Tacoma metropolitan area. It originates in Bow Lake east of the airport at an elevation of about 106 meters. It flows through the Tyee Golf Course southwesterly, then ultimately into Puget Sound at Des Moines Creek Beach Park. Ninety-four wetlands have been delineated within the project area.
Generally speaking, aquatic habitat within the three streams has been reduced and degraded (FEIS 1996; Des Moines Creek Basin Committee 1997; Hillman et al. 1999; Parametrix 1999a). Miller, Walker, and Des Moines creeks have little habitat diversity and complexity. The lower reaches of each stream consist mainly of turbulent fast water, with non-turbulent fast water and scour pools increasing in an upstream direction (based on fall 1998 observations, Hillman et al. 1999). Fine sediments within pools and riffles are relatively high, with surface fines approaching 100% in the upper reaches of Miller and Walker creeks. In Des Moines Creek, surface fines in the upper reaches are less than in Miller or Walker creeks, but are still high. Aquatic habitats such as undercut banks, boulder cover, and large woody debris are scarce in the survey streams. The lack of woody debris is significant because woody materials have an important influence on channel hydraulics and play an important role in the physical processes associated with pool formation and sediment control (Salo and Cundy 1987). Woody debris also provides excellent cover and feeding stations for juvenile and adult fish, especially salmonids. Although the current information on habitat within the streams is useful, detailed descriptions of habitat quality and availability are needed to assess potential effects of the proposed project. This requires an understanding of the habitat requirements of fish within the systems and how the proposed project will affect those habitats. This information is also necessary for establishing a valid monitoring program.
With the possible exception of Des Moines Creek, stream biota and factors affecting them are poorly understood within the watersheds. As far as we know, fish populations have been but little studied within the Miller Creek watershed. Hillman et al. (1999) described the habitat in Miller, Walker, and Des Moines creeks. They also described abundance and distribution of redds and spawning adults in the fall and winter of 1998-99. They identified both coho and chum salmon spawning in all survey streams; coho being the most abundant. They found that many female coho died before voiding most of their eggs. This unusual condition may suggest a potentially serious ecosystem health problem within the watersheds. In addition to coho and chum salmon, Hillman et al. (1999) found adult steelhead in Miller and Des Moines Creeks. They found one cutthroat trout redd in Walker Creek. The researchers were unable to determine if the cutthroat observed on the redd was a sea-run or resident fish. However, the large size of the fish (about 15 inches) indicates that it was quite likely a sea-run cutthroat. Hillman et al. (1999) found no pink or chinook salmon or bull trout within the survey streams. Pink salmon have been observed occasionally in Des Moines Creek (Des Moines Creek Basin Committee 1997). Des Moines Creek is also known to support resident species, including cutthroat trout, rainbow trout, pumpkinseed sunfish, largemouth bass, bluegill, black bullhead, and sculpins (FEIS 1996; Des Moines Creek Basin Committee 1997). Resident forms in Miller Creek watershed probably include cutthroat trout, pumpkinseed, and sculpins. Although this information is useful, it does not adequately describe abundance, distribution, or health of fish populations within the watersheds. This additional information is needed to assess and monitor potential impacts to the aquatic ecosystem.
We found no information on benthic macroinvertebrates or hyporheic organisms within the watersheds. Data on macroinvertebrates and hyporheic organisms can be useful in assessments of potential impacts to biological resources and reference data against which to measure effects of the proposed action. Not only are these organisms important to fish (e.g., food source), they are also indicators of biological integrity. That is, numerical data on benthic macroinvertebrates serve to assess the relative health of the aquatic ecosystem. Indices such as taxa richness, Hilsenhoff Biotic Index (HBI), Shannon-Weaver Index, and EPT richness and percentage can be used to evaluate macroinvertebrate communities in the watersheds. The HBI would be most useful because it is a measure of species sensitivity mostly to organic pollutants. With the proposed loss of wetlands, it is possible that hyporheic organisms will be negatively affected.
We do not know the primary factor or factors that currently limit trout and salmon production within these three streams. However, factors associated with urbanization are likely responsible (FEIS 1996; Parametrix 1999b). Factors involved in urbanization include encroachment, channelization, hydraulic alterations, barriers, diversions, roading (both paved and unpaved roads), pollution, and stream burial in culverts. These activities have reduced habitat by direct and indirect channel and floodplain alterations, alteration of stream flows, removal of riparian vegetation and prevention of regrowth, and degradation of water quality. Because urbanization removes riparian vegetation, streams tend to become less stable and habitat diversity (complexity) decreases. As a result streams widen and become shallower with subsequent loss of pools. Bank erosion increases and reduces both spawning and rearing habitat. Channelization and bank hardening also reduce habitat diversity by increasing bedload transport, which increases fine sediment deposition in downstream spawning and rearing areas. Urbanization can indirectly affect production of fish populations by increasing angling pressure and poaching. Increased angling pressure and poaching can quickly reduce numbers of salmon and trout.
Clearly, there are several activities associated with urbanization that have or continue to affect aquatic habitat and fish production within the three watersheds. However, we found no information on the ways that the effects of these activities and the proposed project will interact and accumulate in the watersheds. Current activities such as encroachment, channelization, pollution, and roading have reduced stream sinuosity, bank and channel stability, riparian vegetation, stream shading, recruitment of large woody debris, and stream habitat complexity. Substrate, water, and pool quality have declined. Water temperature, erosion, and recruitment of fines have increased. Noticeably lacking is any discussion of how these current activities interact among themselves or with the proposed activity. The Port of Seattle (hereafter referred to as the "Port") must first identify current conditions and limiting factors within the watersheds. Then they need to examine how their proposed activities will interact and accumulate within the environment.
Construction of a third runway at Sea-Tac will have negative effects on the aquatic environment of Miller, Walker, and Des Moines creeks. These effects will occur during construction and some will last after project completion. Given the current information available, we believe the most important factors likely to affect aquatic habitat and fish populations include loss of wetlands, changes in stream flow, channel modification, and reduced water quality. The cumulative effects of these factors and their interactions with fine sediment delivery, surface runoff, and instream habitat quantity and quality will likely reduce aquatic habitat and fish populations. In the following sections we address potential effects separately.
Probably a significant effect will be the filling or partial filling of 51 (18.33 acres) of the 94 (147.17 acres) wetlands within the project area. This equates to a 12.5% reduction in wetlands within the project area. Aside from the fact that wetlands provide habitat for a diverse biological community, both terrestrial and aquatic, they also recharge aquifers or ground water, reduce peak stream flows by containing rainwater and surface runoff, maintain stream flows during dry periods, and act as natural filtering systems or sinks for pollutants and fine sediments. Although the FEIS suggests that these wetlands occur within topographic depressions in till soils and therefore the wetlands do not contribute groundwater to streams during base flow, we remain unconvinced. It is quite likely that "windows" of relatively-permeable outwash soils occur within these wetlands, allowing some groundwater recharge to streams. This topic needs further research. Hydraulic modeling performed to date seems to suggest that the proposed project will not significantly alter stream flows. However, failure of proposed mitigation measures to contain runoff will increase peak flows, with negative effects on fish populations within Miller, Walker, and Des Moines creeks.
Reduction in wetlands and added acreage of impervious surfaces probably will increase sediment delivery to the streams and will artificially increase the magnitude and frequency of high discharge, resulting in elevated erosion rates. High flow events occur mainly during the fall and winter, which coincides with spawning and incubation of salmon and cutthroat trout. Artificially-increased high flows will increase the transport of fine sediments already contained within the upper reaches of all three streams. These sediments will then deposit in the lower reaches where spawning and rearing occurs (Hillman et al. 1999; Des Moines Creek Basin Committee 1997). Sediments that enter the system during construction will also be transported to spawning and rearing areas during high flow events. Deposition of fines on and in redds can reduce egg-to-fry survival. High flows can also scour redds, destroying embryos. Sediments transported during high flows may fill the limited pools that provide important rearing habitat for juvenile and adult salmonids and other species.
The increased frequency and extent of low flow periods, which may result because of reduced storage of groundwater during high flows (see next section), may also have deleterious effects on both anadromous and resident species. During low flow events, water temperatures may increase and dissolved oxygen levels decrease. These concerns have recently been noted in Des Moines Creek (Des Moines Creek Basin Committee 1997). Both high and low flow conditions have the potential of reducing the survival of fish within the system. Also, during certain times of the year, low flows could reduce living space for salmonids and stream connectivity for resident salmonids.
Floodplain water retention would probably be lost under the steeply-sloped fill at the side of the new runway. This change, coupled with an added acreage of impervious surfaces associated with the new runway, would increase high flows in lower Miller Creek. Higher peak flows would potentially increase stream power, hence erosion and scouring in various sections of Miller Creek. A particular concern is the potential to increase scour in coho and chum salmon redds in lower Miller Creek, and the possible recruitment of fines to the stream channel from erosion caused by higher stream velocities and volumes. High flows documented during the 1995-1996 winter season appeared to have scoured some redds in Des Moines Creek (Des Moines Creek Basin Committee 1997)
We note that the increased impervious surface in the Miller Creek basin is to be offset with removal of 51.8 acres of streets, driveways, and rooftops as part of the permit action. However, the present impervious area (51.8 acres) appears discontinuous and interspersed with areas where water can filter into the substrate. The new impervious surface is more continuous and monolithic, lacking interspersion with absorptive substrate. It seems doubtful that the tradeoff will be flow-neutral. The issue of interspersion effects on the tradeoff was not addressed, so far as we can tell, in the discussions in the draft mitigation plan.
In the Des Moines Creek area, 114 acres of new impervious substrate will be added. This also would increase peak streamflow. Mitigation is proposed for the new condition. Stormwater detention facilities, including 180 acre-feet in the west branch of Des Moines Creek, would be added, with the aim of detaining the 2-, 10-, and 100-year peak flows to their pre-developed condition, with base year1 defined as 1994. The goal would be to prevent any increase in peak flows. It is imperative from a fisheries standpoint that this goal be met.
1We cannot determine whether the area that lies under the 118 acre-feet is included in the future area of impervious surface.
With the exception of chum salmon, which migrate to sea shortly after emerging from the redd, all anadromous and resident fishes in Miller and Des Moines Creek depend for living space in summer on the extent of stream surface areas, hence upon summer streamflow. Increases in impervious substrate in the Miller Creek and Des Moines Creek basins are likely to decrease stream-base flow as infiltration and absorptive surfaces decrease. More water will be conveyed in higher-flow periods, hence less will be available for summer base flows. This, in turn, will reduce living space for resident and migratory fishes. The draft mitigation plan and permit information are quite vague on how base flows will be maintained. Calculations or modeling do not offer assurance that mitigation through new floodplain development, flow augmentation (well water), or enhanced infiltration will maintain summer base flows.
The issue of summer base flows ties in with the provision of habitat complexity with wood and rock. If summer base flows decrease, structural effectiveness could easily be reduced. The public notice does not directly mention base-flow maintenance.
As we noted above, the proposed project will increase the total impervious surface area. Impervious surfaces effectively decrease infiltration surface area. That is, more of the water will flow overland to storm drains and to stream channels. This will further exacerbate current volume and timing of runoff. For example, research in King County during the last decade has shown dramatic effects of storm-water runoff from urban and suburban areas on stream channel stability and structure (Palmisano et al. 1993). The time of arrival of that portion of rainfall that reaches the channel is controlled by whether it flows primarily through the subsurface or over the surface and how quickly it is collected into open channels (Booth 1991).
Another relevant point of the runoff studies conducted in King County is that hydrologic changes imposed by urban development profoundly affect the disturbance frequency in developing basins. With the continuous computer model (HSPF), Booth (1991) determined the occurrence between 5-year flood events in a sample basin under completely forested conditions and fully urbanized conditions (40% impervious surface). Booth (1991) used the same 40-year precipitation record for both simulations. Results in the forested watershed showed seven flood occurrences at or above the predevelopment 5-year discharge, with as much as 14 years between floods. A similar simulation in an urbanized watershed had only 1 year without a predevelopment 5-year flood event. Increases in the impervious surfaces of the Miller and Des Moines watershed will further affect the hydrologic regime within the basins. Currently, impervious surfaces cover about 35% of Des Moines Creek basin and the percentage is expected to increase to over 47% (Des Moines Creek Basin Committee 1997).
We believe that the cumulative and interactive effects of urbanization and the proposed activities will result in reductions of fish habitat that cannot be restored or rehabilitated. Booth (1991) opined that many urban streams have already reached a point where rehabilitation is unlikely. Further changes in the stream habitat resulting from urban development will likely be permanent and potentially irreversible. As reported in Palmisano et al (1993), preliminary modeling results from site specific watershed data indicate that as little as 10% impervious surface in a watershed may destabilize stream channels. Furthermore, a decrease in water infiltration rate and subsequent loss of potential water retention caused by the impervious layer could also affect low flow conditions in summer.
During construction, a total of 20.5 million cubic yards of fill will be used. A construction project this large has a high likelihood of increasing recruitment of fines to stream channels. Some recruitment is inevitable, in spite of the best planning and execution. The channels of Miller Creek and Des Moines Creek have already been degraded as urbanization increased erosion and deposition of fines. As we described earlier, increased sediments can adversely affect salmon and trout populations. Fine sediments that cover substrate can affect food availability by reducing suitable substrate for macroinvertebrates (Furniss et al.1991). Excessive sediments can also decrease survival to emergence for salmonids (Chapman 1988), and modify the stream channel and reduce rearing habitat by decreasing the depth and number of pools (Furniss et al. 1991). In fact, some of these effects have already been observed in Miller, Walker, and Des Moines creeks (Appendix C in Des Moines Creek Basin Committee 1997; Hillman et al. 1999; Parametrix 1999a).
The FEIS estimates that 80% of the total suspended solids that will enter during and after construction will be captured by wet vaults, wet ponds, and bio-filtration swales. The remaining 20% will enter Miller and Des Moines creeks. The income is estimated at 28 to 71 tons in Miller Creek, and 24 to 60 tons in Des Moines Creek. The current loading of sediment to Miller Creek is estimated as 10 tons annually (Parametrix 1999a). The transport of additional sediments to these streams will further degrade aquatic habitat, likely reducing fish production.
Storm-water runoff from airports can contain a variety or contaminants, many of which are hydrocarbon-based (e.g., fuels, oil, grease, rubber products). Additionally, deicing and anti-icing compounds are used to remove ice and snow buildup on runways and aircraft. The most common deicers contain either ethylene glycol or propylene glycol as the deicing agent, and other constituents including buffers, wetting agents, oxidation inhibitors, and polymers. These compounds can also appear in runoff. The additions of a third runway will increase the use of these chemicals, thereby increasing the risk of these agents entering the streams. Major spills of jet fuel have occurred in the past (mid 1980s), nearly eliminating all aquatic life along most of Des Moines Creek (Des Moines Creek Basin Committee 1997). It is not unreasonable to assume that spills will occur again.
Water quality in Miller and Des Moines creeks is of particular concern, especially because egg retention in coho carcasses appears excessive. We have found a mean voidance in coho in Des Moines Creek of only 16%. In other words, 84% of eggs were never deposited in redds. The highest average voidance (37%) occurred in Walker Creek (Hillman et al. 1999). Many salmon die before they spawn, and some salmon die before they spawn completely. Our experience with coho has been that females usually void most of their eggs, and few fish die unspawned.
We do not know why coho in these streams fail to void eggs. We do know that non-point pollution occurs in Miller and Des Moines creeks. The draft mitigation plan notes that streets and highways contribute heavy metals and hydrocarbons (gas and oil). The concentrations of these materials in waters draining the area do not appear excessive, according to information in the draft plan. Residues from aircraft exhaust emissions may fall on the streams when wind conditions permit. Pesticides and drainage from septic systems are present in urbanized zones, but we have no information that implicates them in the pre-spawning mortality suffered by coho. However, if spawning failure is related to water-quality, it is likely that spawning failure will continue after completion of the proposed project.
A straight, channelized section of Miller Creek would be relocated. The relocation will increase stream length by 100 ft to about 1,080 ft. The channel substrate would be gravel or rocks. A riparian buffer would be planted. We regard these changes as positive, and with potential to increase aquatic insect drift in Miller Creek and with long-term potential to improve habitat for resident fishes, particularly cutthroat trout. However, we found no detail on sheets 13-17 (sheets that deal with the relocation) that describes how, or if, habitat diversity would increase as a result of deflectors, boulders, rootwads, and log structures. We are curious why pg 5-11 in the draft mitigation plan (Parametrix 1999a) says: "LWD (deflector logs, angle logs, and root wads), as well as boulders would be used to stabilize the substrate, protect the upper banks from excessive erosion, and provide hiding and holding habitat for fish during higher flow periods" (Italics ours). Nothing is said in the Public Notice about these habitat enhancements. Also, no detailed sheets on fish habitat enhancement are provided for the 980-foot section, as they are for the Miller Creek segments farther downstream.
We are also concerned that the italicized phrase above could indicate that fish could access the habitat enhancements mentioned on pg 5-11 of the Parametrix (1999a) document only during higher flows. That may not be the intent of the mitigation plan, but the italicized wording is not reassuring. We believe that the relocated stream section should have low-flow habitat enhancement as well, and that the Public Notice should have detailed how habitat-enhancement features would be used in the relocated stream section. Clearly, additional information is needed before we can assess potential impacts.
Four in-stream enhancement projects are noted on sheet 11 and sheets 18-21 of the Public Notice. The latter four sheets detail locations of structural modifications between the relocated stream segment and 8th Avenue South. Our experience with, and observations of, in-stream structures have demonstrated that structural enhancements can range in effectiveness from excellent to worthless. We believe that their efficacy depends a great deal upon the experience and judgement of the designer, on the degree to which plans translate to structures, and on the durability of the features. In-stream fixed debris can end up well above the wetted stream margin, useless to fish. High flows often dislodge deflector logs, rootwads, and angle logs, carrying them out to sea or placing them in positions out of water.
In 1993, a quantitative habitat analysis conducted on Des Moines Creek showed that most of the woody debris was small and located along the edge of or suspended over the stream channel (Des Moines Creek Basin Committee, 1997). These findings were confirmed in another habitat analysis in 1996. The lack of woody debris and location within the stream channel suggest that high flows dictate the position and amount of woody debris in the Des Moines Creek.
We suggest that enhancement projects be bonded in some manner to provide for annual maintenance. The income from the $150,000 trust fund ...to promote enhancement of aquatic habitat in Miller Creek downstream of Port-owned property is unlikely to provide adequately for repair of damage to structures, let alone for assurance that planners and constructors may fail in part.
Based on the information we reviewed, we found no mention of how the Port proposes to monitor aquatic habitat, fish, or aquatic invertebrates within the affected watersheds. We should think that a project as large as the proposed runway expansion would require some form of an aquatic monitoring plan. A valid monitoring design would require suitable baseline (current) information, which is noticeably lacking, with both spatial and temporal replication. Monitoring would require sampling throughout the streams, not just within the zone of the proposed activities, and should include estuary and near-shore habitats. Without a valid monitoring plan, one would not know if the proposed activities negatively (or positively) affect the aquatic community and habitat within the watersheds. Additionally, it is unclear what steps the Port would take if negative impacts were identified. The income from the $150,000 trust fund would not cover potential damages.
Both Puget Sound chinook salmon and coastal/Puget bull trout have been listed under the Endangered Species Act. Coho salmon are candidates for listing under the ESA, and may be listed before completion of Master Plan improvement projects. To the best of our knowledge, bull trout and chinook salmon do not occur within Miller, Walker, or Des Moines creeks. However, coho salmon spawn and rear in all three streams. In this section we discuss probable effects of the proposed project on bull trout and chinook salmon. Probable effects on coho salmon and their habitat are discussed in other sections of this letter.
Given the current conditions of Miller, Walker, or Des Moines creeks (i.e., warm summer temperatures, high levels of fine sediments, etc.), it is unlikely that bull trout would spawn or rear in these streams. These conditions, however, would not preclude anadromous bull trout from temporarily foraging on salmon eggs during salmon spawning in fall and early winter. Additionally, bull trout may occur temporarily in the lower reaches of the streams during cooler times of the year (Parametrix 1999b), or in the estuaries and near-shore habitats. More information is needed to establish the presence or absence of bull trout in the lower portions of these streams, estuaries, and near-shore habitats.
Although we found anecdotal accounts of chinook salmon residing within the streams (C. Gower, personal communication), we found no information documenting the historical presence of chinook in the streams. Field work by Hillman et al. (1999) found no evidence that chinook salmon were spawning in the streams. Although these streams are probably too small to support stream-type chinook, it is conceivable that ocean-type chinook may be able to use the lower portions of Miller and Des Moines creeks for spawning. In addition, chinook may occur within the estuaries and near-shore habitats. Clearly, more work is needed to establish the presence or absence of chinook in these streams and near-shore habitats.
If bull trout and/or chinook salmon are occasionally present in these streams or near-shore habitats, we believe the BA is overly optimistic in their conclusion that the potential direct, indirect, and cumulative effects "may affect, not likely to adversely affect" bull trout. A project this large will affect sediment delivery, streamflows, habitat conditions, and water quality (see Sections above). These effects would likely reduce fish production.
Based on the information available to us and our work within the watersheds, we believe that the proposed Sea-Tac runway project will have some short-term and long-term effects on the aquatic communities within Miller Creek and Des Moines Creek watersheds. We believe that the proposed project will likely reduce floodplain water retention, increase peak flows, reduce summer low flows, and increase fine sediment recruitment. It will decrease bank stability, habitat complexity, and water quality. These changes will likely reduce fish production.
Recent studies conducted within the watersheds indicate that aquatic habitat is already degraded. Although limiting factors have not been identified, urbanization probably has contributed most to the current state of the aquatic habitat and fish production. Cumulative and interactive effects of the proposed project on existing habitat, fish, and aquatic invertebrates have not been described. Baseline (current) conditions of the aquatic habitat and biota are lacking. Without adequate baseline information, one cannot assess the magnitude of possible impacts. Measures to mitigate for lost fish production and habitat may miss the target if current conditions (fish, invertebrates, habitat) and limiting factors are not better understood. One cannot adequately monitor effects of the proposed activities if baseline information is lacking. We suggest, on the basis of existing information and deficiencies in the available data on stream habitat and biota, that approval of the Port permit to construct a third Sea-Tac runway would be premature.
Booth, D. B. 1991. Urbanization and the natural drainage system-impacts, solutions and prognoses. Northwest Environmental Journal 7:93-118.
Chapman, D. W. 1988. Critical reviews of variables used to define effects of fines in redds of large salmonids. Transactions of the American Fisheries Society 117:1-21.
Des Moines Creek Basin Committee. 1997. Des Moines Creek Basin Plan. Prepared by City of Sea-Tac, City of Des Moines, Port of Seattle, and King County.
Federal Aviation Administration. 1996. Final Environmental Impact Statement for proposed master plan update development actions at Seattle-Tacoma International Airport. Volume 1 or 7, Chapters I through VI, Appendices A-B.
Federal Aviation Administration. 1997. Final Supplemental environmental impact statement for the proposed master plan update development actions at Seattle-Tacoma International Airport. Volume 1 – main text and appendices A through C-1.
Furniss, M. J., T. D. Roeloffs, and C. S. Yee. 1991. Road construction and maintenance. Pages 297-323 in: W. R. Meehan, ed. Influences of forest and rangeland management on salmonid fishes and their habitats. American Fisheries Society Special Publication 19.
Groot, C. and L. Margolis, 1991. Pacific salmon life histories. UBC Press, Vancouver, BC. Canada.
Hillman, T. W., J. R. Stevenson, and D. J. Snyder. 1999. Assessment of spawning and habitat in three Puget Sound streams, Washington. Report to the Airport Community Coalition, Des Moines, WA.
NRPD & SWMD (Natural Resources and Parks Division & Surface Water Management Division). 1987. Reconnaissance report No. 12, Miller Creek Basin. NRPD and SWMD, King County, Washingtion.
Palmisano, J. F., R. H. Ellis, and V. W. Kacynski. 1993. The impact of environmental and management factors on Washington’s wild anadromous salmon and trout. Prepared for the Washington Forest Protection Association and The State of Washington Department of Natural Resources, Olympia, Washington.
Parametrix, Inc. 1999a. Natural resource mitigation plan (draft). Prepared for the Port of Seattle, Seattle, WA.
Parametrix, Inc. 1999b. Biological assessment, master plan update improvements, Seattle-Tacoma International Airport (revised draft). Prepared for the Port of Seattle, Seattle, WA.
Salo, E. O. and T. W. Cundy, editors. 1987. Streamside management: forestry and fishery interactions. University of Washington Institute of Forest Resources, Contribution No. 57. Seattle, WA.
USACE. 1999. Public notice of application for permit. Port of Seattle, Seattle-Tacoma International Airport, Sea-Tac, WA.
Information supplied by the ACC.
Designed and coded by Richard T. Kennedy.
The Des Moines City Attorney would like you to read the disclaimer.
Last modified: 16 January 2000