In the Spring of 2000, Spokane County Utilities began the process of
developing a Wastewater Facilities Plan to identify wastewater
facilities and programs that must be implemented to meet the long-term
needs of the County. Spokane County began the wastewater planning
process to evaluate future County wastewater service areas, project
future wastewater flows, and develop recommendations for new wastewater
treatment facilities and reclamation programs.
This chapter provides an overview and description of the alternatives
being considered for expansion of Spokane County's wastewater treatment
facilities. The County is considering five alternatives for
treatment facility locations and configurations. In addition, the
County is considering various alternatives for other system components
including demand management, effluent end use, and biosolids management.
The other system component programs are also presented in this chapter.
The evaluation criteria for screening the initial treatment facility
alternatives and the alternatives considered but not selected are
described. In addition, this chapter describes the No Action
alternative, as required by the Washington State Environmental Policy
Act (SEPA).
The Spokane Advanced Wastewater Treatment Plant (SAWTP) is operated by
the City of Spokane. The County has an interlocal agreement to
send up to 10 mgd to the SAWTP. This alternative would expand the
existing SAWTP to handle all flows from the County and City through the
year 2025. The level of treatment would be upgraded to tertiary
treatment. The County's average flows in the year 2025 are
projected to be 22 mgd with the combined City and County flows estimated
to be 65 mgd. The capacity of the SAWTP is currently rated at 40
mgd. This Alternative would require a new interlocal
agreement between the County and City.
This Alternative would require expansion of the County and City
conveyance systems, especially the system that conveys flows from the
Valley to the SAWTP. The current interlocal agreement between the
County and City sets the allowable peak flow through the City's
interceptor system at 15.5 mgd. Projected peak flows from the
Valley are 37 mgd. Conveyance of the amount of flow in excess of
15.5 mgd will require pumping through a new forcemain to the SAWTP.
This would require two new pumping stations and approximately 8 miles of
forcemain. The forcemain would be routed primarily through densely
developed portions of the City. Segments of the City's interceptor
system would also need to be expanded in North Spokane.
This alternative would locate a new 12-mgd plant in the Spokane Valley
east of the Spokane city limits. Flows generated in the Spokane
Valley would be sent to the new plant. The new plant would provide
tertiary treatment and would discharge treated effluent to the Spokane
River below Upriver Dam. The County would retain its current
10-mgd capacity allocation at the SAWTP and all flows generated in North
Spokane and a portion of the flow from the Spokane Valley would continue
to be sent to the SAWTP. The County has identified this
alternative as the Preferred Alternative.
The new plant most likely will be located along the North Valley
interceptor and will require a new influent pumping station to lift the
North Valley flow into the treatment plant. A new pump station and
force main will also be required to convey flow from the Spokane Valley
interceptor to the new treatment plant. This would substantially
reduce the amount of flow conveyed from the Spokane Valley to the SAWTP.
This could reduce Combined System Overflows (CSOs) in the central
portion of the City's conveyance system. Some segments of the
City's interceptor system would require replacement or the installation
of parallel sewers to convey future North Spokane flows to SAWTP.
Under this alternative a new 12-mgd plant would be constructed in the
south-central area of Spokane, within the city limits. This plant
would provide tertiary treatment and serve flows generated in the
Spokane Valley and the southern portion of the City's service area..
The County would retain its 10-mgd allocation in the SAWTP to
handle flows from North Spokane and a portion of the flows generated in
the Spokane Valley. The new plant would be jointly operated by the
City and County.
Because of the County's limited conveyance capacity in the City system,
all flows sent to the new plant would be pumped through a new forcemain.
The forcemain would be constructed through developed portions of the
City and would require the construction of pump stations.
This alternative is similar to Alternative 2, but would construct two
plants in the Mid-Valley area—a 5 mgd plant and a 7 mgd plant.
Both plants would provide tertiary treatment. The two smaller
plants would be located close to where wastewater is generated and where
the treated effluent could be sent to reuse applications. Flows
from the North Spokane area and a portion of the flows from the Spokane
Valley would continue to be sent to the SAWTP. The County would continue
to send 10 mgd to SAWTP.
Under this alternative, no wastewater treatment expansion would occur.
The County would continue to send all wastewater flows to the SAWTP
plant up to its maximum 10 mgd agreement. No new plant would be
constructed and the SAWTP would not be expanded. Under this
alternative, the County would reach its 10 mgd allocation by 2006 or
2007.
If the County takes no action to expand its wastewater treatment
facilities, the permit requirements for discharge to the Spokane River
could be violated and fines could be levied against the County. No
action could also result in a building moratorium and the imposition of
judicial control over the County’s wastewater treatment program.
In evaluating the alternatives for treatment plant facilities, Spokane
County applied the following criteria.
This criterion addressed the ability of an alternative to meet the
County’s near-term and long-term requirements for wastewater treatment
capacity. The near-term requirement relates to the ability to
implement the solution before 2007, when County flows are projected to
reach the capacity allocation in the SAWTP. The long-term
requirement relates to the alternative’s ability to provide a long-term
(50-year) solution.
This criterion considered the operational complexity of the alternative.
Since all alternatives would likely use similar treatment technologies,
the number of plants and major pumping facilities that must be
maintained primarily would affect the criterion. Fewer facility
requirements would result in a higher rating.
This criterion considered the extent and complexity of sewers and pump
stations that must be implemented.
Consideration was given to challenges associated with acquiring property
and permits. Generally, siting a North Spokane or In-City plant
was considered more challenging than siting a Mid-Valley plant.
Also, siting multiple new facilities resulted in a lower rating.
This factor relates to the County’s ability to implement the alternative
on its own, without relying on actions by other jurisdictions.
This criterion is significant given the need to implement additional
capacity by 2007.
This criterion addressed anticipated impacts to the receiving streams
and the potential for compliance with discharge permits.
Generally, alternatives that spread the location of effluent discharge
along receiving waters were rated higher because they would lessen
localized impacts. Alternatives with multiple plants were rated
lower because they would require compliance with more permits.
This factor considered the proximity of the treatment plants to
potential reuse opportunities.
This criterion addressed the environmental and community impacts of
building and operating wastewater facilities.
This factor compared total life cycle costs, including capital and
operating expenses.
This factor considered the risk associated with the economic assumptions
used in the analysis. Alternatives that relied on other
jurisdictions buying conveyance or treatment capacity from the County
were rated lower. Also, those alternatives that required other
jurisdictions to participate in the financing of projects were rated
lower.
The final action alternatives were compared against an array of
evaluation criteria using a modified "Consumer Reports" rating system.
The results are summarized in Table 4. The No Action Alternative
was not included in the evaluation because it does not involve any
action from the County.
Table 4.
Evaluation Criteria Results
Initially the County considered 13 wastewater treatment alternatives.
The 13 alternatives are variations of the four final alternatives
described above. The main components that vary in the alternatives are
the size of the treatment plants and the amount of wastewater flows that
would be sent to the SAWTP. In addition, the initial alternatives
considered construction of a 5 mgd plant in the North Spokane area to
handle flows from the North Spokane Service Area.
The size of treatment plants being considered under the initial
alternatives ranged from 3 and 4 mgd to 17 mgd. The size of the plants
varied depending on other components of the alternatives. Options for
the amount of wastewater flows to be sent to the SAWTP ranged from
discontinuing all flows from the County to the SAWTP, to increasing
County flows to the SAWTP to as much as 22 mgd.
Alternatives 2, 3, and 4 all initially included an option to construct a
small plant in North Spokane with discharge to the Little Spokane
River. This option was considered as a means to handle flows from the
North Spokane Service Area, and to beneficially recharge the Little
Spokane River. This option was eliminated from consideration because of
complications associated with discharging effluent to the Little Spokane
River, a limited number of suitable sites, and major costs associated
with changing the conveyance system.
In addition to the alternatives considered for treatment plant locations
and configurations, the County is considering different alternatives for
other components of wastewater treatment, including demand management,
effluent end use, and biosolids management. The alternatives are
presented below. These system components are intended to be used in
combination with the alternatives for treatment plants to improve
wastewater management in the County. It is likely that the alternatives
selected for these system components will be a combination of the
options presented below.
Demand management is the package of efforts designed to reduce the
quantity and/or strength of wastewater from the North Spokane and
Spokane Valley service areas. If demand management strategies are
successful, the size of treatment facilities could be reduced and costs
lowered. Spokane County already has important demand management
measures in place, including a ban on phosphorous-containing detergent,
an industrial pretreatment program, effective control of infiltration
and inflow, and a requirement that new construction or major remodels
use low volume plumbing. The County is considering the following
alternative measures to further reduce wastewater flows.
A water conservation alternative would include a public education
component to encourage people to use less water in daily activities.
The program would be continuous to help maintain conservation goals. A
second component of the water conservation element would be a plumbing
fixture replacement program to encourage replacement of old plumbing
fixtures. This component could be accomplished through public
education, economic incentives, and coordination with other agencies,
organizations, and businesses. A third component of the water
conservation element would be an inverted rate structure for public
water supply that would charge consumers a higher unit cost for any
water consumed above a base amount.
This alternative would reduce the amount of water that enters the sewer
lines by infiltration from groundwater or inflow from stormwater
runoff. One component of this alternative would be the elimination of
basement sump pump discharges to sewers. In areas of the County with
high groundwater tables, the County would use public education and
limited technical assistance to inform the public of the requirement to
eliminate basement sump pump flows from the sewer system. Another
component of the alternative would be the review of codes, inspection
and enforcement requirements to ensure that future construction would
produce minimal contributions of infiltration and inflow.
This alternative considers measures to further reduce the strength of
industrial wastewater flows. One component would be County review of
ordinances to determine if increased requirements to minimize industrial
wastewater quantities and strengths are needed. Another component of
this alternative would be to implement increased rates or surcharges for
industries or businesses discharging high strength wastes. The County
is also considering establishing requirements or incentives to encourage
industries to maximize water recycling and reuse within their
operations.
The County is considering the following alternatives for how treated
effluent is returned to the environment or beneficially reused. Under
all alternatives the County would comply with state and federal
guidelines and regulations for effluent reuse.
Under this alternative surface water discharge would continue for most
effluent generated by the system. Each of the five wastewater treatment
alternatives assumes that the primary effluent end use strategy will be
discharged to the Spokane River. Surface water discharge could be used
to augment minimum streamflows. The approach includes a relatively low
effluent conveyance cost, and simple effluent management requirements.
Disadvantages of this approach would be limited reuse of the effluent
and discharge of pollutants to the river during critical water quality
periods.
2.5.2.2
Effluent End Use Alternative 2 — Irrigation of Poplar Farms
Under this alternative hybrid poplars would be irrigated with treated
effluent. Hybrid poplars have a high water demand during summer months
and may produce revenue as pulp for paper or as a clear softwood.
Effluent for application would be treated to class C standards and
conveyed 7 to 20 miles to county-owned land.
This alternative would use treated effluent as an irrigation supply for
golf courses, school grounds, parks, cemeteries, highway medians,
industrial campuses, and other greenspaces. Irrigation use of effluent
would require construction of a distribution piping system and may
require storage facilities to hold water until needed. Irrigation of
lands overlying the Spokane Aquifer may require additional treatment to
reduce nitrate-nitrogen concentrations to acceptable levels for drinking
water. Use of effluent for irrigation would be limited to the summer
irrigation season. Effluent end use for irrigation could conserve
groundwater currently used for irrigation and reduce effluent discharge
to the river during the summer.
Another option for effluent end use would be the use of effluent to
irrigate agricultural lands. This alternative would have similar
advantages and disadvantages to the previous alternative. If dryland
areas were irrigated, there would be no reduction in groundwater
consumption. This alternative could benefit dryland agriculture by
allowing the production of higher value crops.
This alternative would provide treated wastewater to industries for use
as cooling water or in process applications. This alternative would
provide a year-round use for treated effluent and could conserve
groundwater currently used by industries. Industrial reuse may require
high treatment costs to meet user needs and more complicated discharge
permitting requirements. In addition, there is the risk that the
industry could relocate and/or change water requirements.
Treated effluent could be used to create constructed mitigation wetlands
or as a reliable water source to restore degraded wetlands. If the
wetlands are located along streams, the water could also be used to
augment streamflows after it is routed through the wetlands. The
advantages of this option include habitat creation, development of a
wetlands bank in the County to facilitate economic development, and the
potential to enhance stream discharge options. The disadvantages would
be a relatively low water demand, high land requirements for wetland
construction, and the potential for adverse public perception of
wastewater use over the aquifer.
Effluent that was treated to a very high level could be used to recharge
the groundwater supply. This could be accomplished through surface
percolation (spreading basins) or direct injection wells. The water
recharged to the aquifer could be withdrawn and used for any permitted
use. The advantages of groundwater recharge are maximum use of the
effluent as a water resource, minimal discharge to streams, and recharge
of the aquifer to provide an adequate water supply for present and
future needs. The major disadvantages are the high cost of treatment to
drinking water standards, the potential adverse public perception of
effluent discharge to the aquifer, and regulatory requirements.
Biosolids are the residual materials from wastewater treatment. They
contain organic matter and plant nutrients such as nitrogen and
phosphorous. Biosolids can make good soil amendments, but the quality
must be managed to minimize the presence of trace toxic materials and
disease-causing organisms. Currently the biosolids produced at SAWTP
are treated to Class B standards to destroy disease causing
microorganisms, to reduce the organic content, and to reduce the water
content. The treated biosolids are trucked to agricultural lands west
of Spokane and used as soil amendments. The following options are being
considered for managing biosolids.
This approach would be similar to the practice currently used at SAWTP,
and is assumed to be the primary biosolids strategy for each of the five
wastewater treatment alternatives. Biosolids would be digested,
dewatered and transported for land application. The sites for land
application could be agricultural land or disturbed mining areas. The
advantages of this alternative are beneficial reuse of the biosolids,
relative low operational cost, well-established technology, and good
demand. The disadvantages would be limited end-uses for biosolids and
the potential that future regulations could require higher levels of
treatment.
Under this alternative, the biosolids would be treated to higher Class A
standards with a high-temperature treatment process prior to
dewatering. Biosolids treated to higher standards have greater
opportunities for end use, greater acceptance by potential users, less
space requirements for treatment facilities, and less susceptibility to
future regulatory change. The major disadvantages would be higher
energy costs for treatment, operation of a more complex treatment
process, and a greater need for odor control.
Under this alternative, Class A standards would be achieved by
composting the Class B biosolids. The end product is well accepted by
end users. The treatment facilities are low technology and fairly easy
to operate. Disadvantages of composting are that it is relatively
expensive, requires land areas and a higher level of dewatering than
land application, and requires significant odor control measures.
This alternative would construct no biosolids treatment facilities at
the new treatment plant sites (Alternatives 2, 3, or 4). All biosolids
would be conveyed to the SAWTP for treatment. The biosolids could be
conveyed by the interceptor pipe system or a separate pipeline. This
alternative would require smaller plant sites for the new plants and
would consolidate all biosolids handling in one location. The major
disadvantages of this approach are increased liquid treatment costs at
SAWTP, possible spillage of solids during CSO events if the solids are
returned to the interceptor or high conveyance costs of constructing
dedicated pipelines. Under this alternative, the County would be
dependent on the City for biosolids treatment and disposal and an
agreement between the County and City would be required to implement the
proposal.
This alternative would incinerate dewatered biosolids at the regional
solid waste incinerator. The advantages of this approach would be a
high level of volume reduction and multiple use of a regional waste
management facility. The disadvantages would be air quality concerns
and permitting issues, high energy costs, potential compatibility issues
with the solid waste system, and failure to beneficially use the
biosolids.
Under this alternative, the County would contract with a private vendor
to manage the biosolids, with the vendor hauling the material to a
processing site. This approach is used in some places in the region,
including ECO composting in Missoula, Montana. The advantages of this
approach are lower capital costs, reduced space requirements for
treatment facilities, and simpler siting of new treatment plants. The
disadvantages would be high transportation costs, potentially higher
operating costs, and increased risk through dependency on a private
entity.
3.0
Impacts of alternatives and mitigation
This chapter assesses the impacts of the proposed alternatives for
expansion of wastewater treatment facilities in Spokane County. The
impacts of the alternatives for other system components are described in
Chapter 4. Based on results of the public scoping process, the
assessment includes a discussion of impacts associated with the
following elements of the environment: land use, water resources,
environmental health, plants and animals, energy and natural resources,
air quality, and transportation. This chapter describes the affected
environment, construction and operation impacts, and appropriate
mitigation measures for each of these elements.
This section describes the land use effects
associated with construction and operation of wastewater treatment
facilities, and the project's consistency with adopted land use plans
and zoning codes. Relevant land use regulations for Spokane County and
the City of Spokane are described, including Comprehensive Plans, Zoning
Codes, and Shoreline Programs.
The portions of Spokane County being considered for wastewater treatment
facilities are designated in a variety of land use classifications,
including residential, commercial, industrial, mixed use, rural
conservation, small track agriculture, and mineral land. Most of the
area near the Spokane city limits and near the Spokane River has been
developed as residential, commercial, or industrial. Areas further east
and further from the river are less developed and are generally rural or
agricultural. The area within the city limits under consideration for a
new wastewater treatment plant has been developed as residential,
commercial, or industrial.
The Washington Growth Management Act (GMA) of 1990 requires that cities
and counties prepare comprehensive plans that conform with GMA goals and
urban growth area designations, and with population projections
developed under the GMA planning process. In August 2001 Spokane County
adopted a revised Comprehensive Plan based on revisions to the 1994
document, Countywide Planning Policies. Spokane County prepared
a draft and final Environmental Impact Statement on the Recommended
Comprehensive Plan. The revised Comprehensive Plan contains
policies for capital facilities and utilities, including wastewater
treatment facilities.
The City of Spokane adopted a revised Comprehensive Plan on May
21, 2001 (Johnston, 2001). A Draft Comprehensive Plan and Draft
Environmental Impact Statement (City of Spokane, 2000) and a
Final Environmental Impact Statement for the Recommended Comprehensive
Plan (City of Spokane, 2001a) were prepared in support of the
revision process. The revised Comprehensive Plan contains
policies for capital facilities and utilities, including wastewater
treatment facilities.
The GMA requires that a comprehensive plan or development regulation
must allow for the siting of an essential public facility. The GMA
directs counties to "provide for a cooperative interjurisdictional
approach to siting essential public facilities of a countywide, regional
or statewide nature consistent with the Countywide Planning Policies" (WAC
365-195-340.3b). In 1996, the County approved the Growth Management
Essential Public Facilities Technical Committee Report (Spokane
County, 1996). The report was submitted to all Spokane County
jurisdictions for inclusion in their comprehensive plans. The report
includes a Model Siting Process, an Interjurisdictional Consistency
Review Process, and an inventory of existing essential facilities.
Sewage treatment facilities are included as an essential public facility
of a regional/countywide nature. The report is included as part of the
2001 Recommended Comprehensive Plan.
The Model Siting Process includes the following steps:
·
Step One: Identify the proposed project as an
essential public facility.
·
Step Two: Classify the facility as having a
statewide, regional/countywide, or local significance.
·
Step Three: Provide early notification and
involvement of affected citizens and jurisdictions allowing for
opportunities to comment on the proposal. The nature of the factors
making the facility difficult to site should be considered when
determining the appropriate level and type of citizen participation in
the siting process.
·
Step Four: Applicants for statewide and
regional/countywide significant facilities should provide an analysis of
alternative sites considered for the proposed facility.
·
Step Five: The proposed facility should be
reviewed for impacts of the facility on regional growth planning
concepts such as the urban nature of the facility, existing urban growth
near the facility site, compatibility of urban growth with the facility,
compatibility of facility siting with respect to Urban Growth Area
boundaries, urban sprawl, economic development, and affordable housing.
·
Step Six: Proposed essential public facilities
should be reviewed for site development criteria including the time
required for construction, property acquisition, control of onsite and
offsite impacts during construction, and expediting and streamlining
necessary government approvals and permits if all other criteria have
been met.
·
Step Seven: The proposed facility should be
reviewed to determine if the financial impact on the jurisdiction can be
reduced or avoided.
The siting of a new wastewater treatment plant, if recommended by the
Board of County Commissioners, will be consistent with this process.
The Spokane County Wastewater Facilities Plan is consistent with the
recently adopted Spokane County Comprehensive Plan. The County’s
Division of Planning and Utilities Division worked together closely to
develop consistent projections for population, commercial and industrial
growth within the County’s Sewer Service Area. The estimates of
population served by the County’s wastewater treatment facilities are
based on population growth projections and include extension of service
to existing populations in the County not currently served by sewers.
These areas have been identified for future connection to the County
sewer system through the Septic Tank Elimination Program to protect
water quality in the Spokane Aquifer.
Zoning Ordinances for both Spokane County and the City of Spokane direct
development in the area (Spokane County, 1998). Spokane County's Zoning
Ordinance (Chapter 14) includes wastewater treatment facilities in its
definitions of a Public Utility Distribution Facility and a Public
Utility Transmission Facility. Both distribution and transmission
facilities are permitted in all residential zones. In business,
industrial, mining, and agricultural zones, distribution facilities are
permitted. Transmission facilities are permitted subject to the
following conditions:
·
The utility company shall secure the necessary property or
right-of-way to assure the proper construction, continued maintenance,
and general safety to the properties adjoining the public utility
transmission facility;
·
The facilities shall be compatible with the surrounding
uses either by distance, landscaping, buffering, or design, as
determined by the Zoning Administrator; and
·
The height of the structure above ground does not exceed
125 feet.
The City of Spokane allows sewage treatment plants in all zones by
special permit. According to Article IV: Special Uses, subsection
13.19.310: Uses by Special Permit in Any Zone, of the Spokane Municipal
Code–Land Use (City of Spokane, 2001), a special permit can be granted
by the hearing examiner in any zone subject to conditions and standards
as deemed necessary by the examiner.
Spokane County's Shoreline Program was adopted in 1974 (Spokane County,
1974). The program regulates development of shorelines within 200 feet
of the ordinary high water mark of streams with flows greater than 20
cubic feet per second (cfs), and lakes, impoundments, and reservoirs
larger than 20 acres. A Shoreline Management Substantial Development
Permit is required for any development within these shoreline areas.
Shorelines in Spokane County are classified in five categories:
Natural, Pastoral, Conservancy, Rural, and Urban. Spokane County's
Shoreline Program permits wastewater treatment facilities in all
shoreline areas except Natural Areas. Shoreline designations along the
Spokane River east of the city limits are either Conservancy or
Pastoral. Wastewater treatment and disposal facilities permitted in
shoreline areas must meet the following conditions:
·
Compelling reasons exist for the specific site selection;
·
Mitigation measures would prevent these facilities from
degrading the shoreline area with odors, noise, and visual detraction;
·
Subsurface disposal of wastewater would be prevented;
·
Facilities would not obstruct or impede the flow of
floodwaters; and
·
Facilities would be designed so that, if flooding
occurred, they would be protected from damage and would continue to
function.
The City of Spokane's Shoreline Master Program was adopted in 1975 and
amended in 1977. The program sets goals and policies, regulates
activities, and authorizes a permit system in a 200-foot shoreline area
adjacent to the Spokane River and Latah Creek in compliance with the
State Shoreline Management Act. In 1982 the City Council approved a
Supplement to the Master Program containing revised use regulations and
administrative procedures (City of Spokane, 1982). Siting of wastewater
treatment plants is allowed in shoreline zones as a conditional use.
During construction, nearby residents and businesses may experience
temporary construction-related impacts, such as increased noise, dust,
and construction vehicle traffic. Traffic may be temporarily rerouted.
These impacts would be temporary and would cease upon completion of
construction.
Direct Land Use Impacts.
Development of treatment plant facilities may require conversion
of existing land uses to a utility use. In addition, conversion of
private property to a public use would remove this land from the tax
rolls, and could have minor impacts on Spokane County's revenue stream.
Under Alternative 5, No Action, a moratorium on building would likely
occur. Design of the wastewater treatment facility would likely
incorporate architectural treatment, landscaping, and/or buffering to
minimize adverse impacts on the adjacent neighborhood, and may raise
land use compatibility issues in some areas. More information on
impacts at specific sites will be available during the next phase of the
wastewater planning process, after the County has selected its preferred
system alternative.
Little or no effect on property values is expected as a result of
Alternative 1 because this alternative is the expansion of an existing
treatment plant. The potential to impact property values is greater for
Alternatives 2 through 4 since they include the siting of one or more
new treatment plants. The extent of impact, if any, will depend on the
location selected for a new plant. Additional information about
potential plant locations will be developed following selection of a
preferred alternative by the Board of County Commissioners.
The following mitigation measures could be implemented to relieve
construction impacts on residences and businesses near the treatment
facility site:
·
Develop a traffic control plan to ensure continued vehicular
access on streets in the project vicinity.
·
Restrict construction to daylight hours of weekdays to reduce
noise impacts on nearby residents; in addition, muffler systems on heavy
construction equipment should be kept in good working order to ensure
maximum noise attenuation.
·
Employ approved dust control measures during the construction
phase. This could include spraying areas of exposed soils with water
and/or palliatives as necessary to reduce visible dust emissions. Dust
emissions from soil transport should be reduced by covering loads,
wetting dry soil, and washing of construction vehicle wheels.
Construction of wastewater treatment facilities is permitted under
County land use and shoreline regulations and would not require any
rezoning or comprehensive plan amendments. If the plant were located
within the Spokane city limits, it would require a Special Permit under
City zoning laws and a Conditional Use Permit if located in the
shoreline zone. Project features such as odor control devices to reduce
off-site odor impacts, visual screening of the facility with vegetation,
and architectural treatment consistent with nearby structures or with a
community-supported design theme would assist in maintaining
compatibility with surrounding uses. If public amenities are included
within the facility's grounds (e.g., park-like use areas, trails, etc.),
the local neighborhood could perceive the addition of public open space
or recreation areas as a beneficial impact.
This section describes the surface and
groundwater resources of the project area and the existing water quality
of those resources. Surface and groundwater are discussed separately,
but the two experience a high degree of hydraulic connectivity in the
Spokane area. Relevant federal, state, and local regulations are
presented. The regulations are presented first to establish the
framework for the following discussions. Impacts of each of the
proposed alternatives on water resources and water quality are
discussed.
Relevant Federal, State, and Local
Regulations. There are numerous federal, state, and local
regulations that apply to water management in the Spokane area. Those
most relevant to construction of new wastewater treatment facilities are
discussed here.
Clean Water Act.
The federal Clean Water Act (CWA) establishes the federal authority to
set water quality and effluent standards to protect the nation's
waters. The CWA makes it unlawful to discharge any pollutant from a
point source without a National Pollution Discharge Elimination Permit (NPDES).
The CWA is administered by the federal Environmental Protection Agency
(EPA), but the authority for permitting, administration, and enforcement
of provisions of the CWA has been delegated to most states. The state
of Washington has received EPA approval to administer the CWA provisions
through the Department of Ecology (Ecology). Ecology issues NPDES
permits that define limits of discharges, and monitoring and reporting
requirements.
Section 303(d) of the CWA requires each state to identify its polluted
water bodies and submit the list to EPA every four years. The 303(d)
list identifies those water bodies that are water quality limited, or
those water bodies that fall short of state surface water quality
standards. The CWA requires that states set priorities for cleanup of
the 303(d) listed waters and establish cleanup plans. One aspect of the
cleanup process is the establishment of Total Maximum Daily Load (TMDL).
A TMDL is a calculation of the maximum amount of a pollutant that a
water body can receive and still meet water quality standards, and an
allocation of portions of that maximum amount to the sources that
discharge that pollutant. A TMDL is established for each pollutant that
exceeds state standards.
Safe Drinking Water Act.
The federal Safe Drinking Water Act (SDWA) of 1974 establishes standards
for drinking water supplies, including groundwater supplies.
Groundwater aquifers that serve as drinking water supplies can be
protected by a "sole source" aquifer designation. A sole source aquifer
is defined as an aquifer that supplies at least 50 percent of the
drinking water to the area overlying the aquifer and in an area where
physical, legal, or economic considerations limit the reliability of an
alternative drinking water source (U.S. EPA, 2001). The sole source
designation is intended to protect such aquifers from contamination.
The primary mechanism for protection is the requirement that all
proposed federal financially-assisted projects that have the potential
to contaminate the aquifer be reviewed by the EPA. Proposed projects
that do not have any federal funding are not required to be reviewed by
EPA. The Safe Drinking Water Act was amended in 1996 to emphasize
protection of drinking water sources through comprehensive watershed
planning. The amendments require states to develop a Source Water
Assessment Plan that delineates source water protection areas,
inventories contaminants in these areas and assesses the water system's
vulnerability to these contaminants. Information from the assessments
must be made available to the public.
State Surface Water Quality Standards.
The Washington Department of Ecology classifies streams by water quality
based on definitions in WAC 173-201A (Water Quality Standards for
Surface Waters of the State of Washington). The Middle Spokane River
from RM 58.0 (Nine Mile Bridge) to the Idaho State line is designated as
a Class A (excellent) stream. Long Lake from Long Lake Dam to Nine Mile
Bridge is classified as "Lake Class," and the Little Spokane River is
classified as Class A. The characteristic uses for these
classifications are water supply, stock watering, fish and shellfish,
wildlife habitat, recreation, and commerce and navigation. Water
quality in the rivers must comply with the water quality standards
specified in WAC 173-201A.
State Groundwater Quality Standards.
The Groundwater Quality Standards (WAC 170-200) are designed to protect
the quality of all groundwater in the state in the saturated zone. The
standards include three mechanisms to maintain high groundwater
quality. Prior to discharge into any of the state’s waters, all known,
available and reasonable methods of prevention, control, and treatment (AKART)
must be employed. The standards include an antidegradation polity to
protect background water quality and to prevent degradation. The
standards also include criteria for the maximum concentration of
specific contaminants. The criteria are based on human health and
welfare standards.
Minimum Flows.
The Department of Ecology is authorized to establish minimum streamflows
on streams and rivers in the state. These minimum flows are established
to protect fish and wildlife, recreation, water quality, navigation, and
aesthetics. The minimum flows are established by administrative rule.
Ecology may not issue water rights that would reduce streamflows below
those established for minimum flows, and Ecology may take enforcement
actions against water users who withdraw water below the established
minimum flows.
Watershed Planning.
In 1998, the state established a watershed planning process for
designated Water Resource Inventory Areas (WRIAs) in the state (RCW
90.82). The authorizing legislation was Senate Bill 2514, and the
process is frequently referred to as SB 2514 planning. The legislation
provides grant funding for local governments to develop watershed plans
for managing water resources and protecting existing water rights. Each
watershed unit must plan for water quantity issues and may opt to plan
for water quality, fish habitat, and instream flows.
Water Quality Management Plan.
There are several groundwater protection programs in place in the
Spokane area. The Water Quality Management Plan is a program managed
jointly by the City of Spokane and Spokane County. The Plan, adopted in
1979, is intended to eliminate the major sources of contamination to the
aquifer and restore its water quality. Tools used to achieve these
goals include 1) zoning ordinances and development restrictions, 2) a
wastewater management plan, 3) stormwater management, 4) a critical
materials ordinance, 5) and public education. The program has
successfully stopped the degradation of water quality in public water
supply wells. The success is largely attributed to the reduction in
individual septic systems located over the aquifer.
Major Surface Water Bodies.
The major surface water body in the Spokane area is the Spokane River,
which flows through the City of Spokane. The major tributaries of the
Spokane River are the Little Spokane River from the north and Latah
(Hangman) Creek from the south.
Spokane River.
The source of the Spokane River is Lake Coeur d'Alene in Idaho. The
river is approximately 111 miles long and drains an area of 6,580 square
miles including the Coeur d’Alene and St. Joe Rivers. The river flows
in a westerly direction from the lake through the City of Spokane (See
Figure 4). Below the city, the river is dammed by Long Lake Dam to form
Long Lake. Below Long Lake, the river flows into the Columbia River at
Franklin D. Roosevelt Lake, which backs up into the Spokane River.
There are five hydroelectric dams on the Spokane River between the Idaho
border (RM 96) and Lake Roosevelt. These dams are Upriver Dam (RM
79.9), Division Street Diversion Dam (RM 74.4), Monroe Street Dam (RM
73.9), Nine-Mile Dam (RM 57.6), and Long Lake Dam (RM 33.9). Post Falls
Dam in Idaho (RM 100.8) influences the hydrology of the Spokane River
through the project area. All of the dams but Long Lake Dam are
run-of-river dams, not storage dams. Run-of-river dams back up only
enough water to establish a constant head for operation of the
hydroelectric turbines.
The Spokane River experiences seasonal streamflow fluctuations, with
flows peaking during spring snow melt and declining in late summer.
Typical streamflows range from less than 2,000 cubic feet per second
(cfs) in August to 20,000 cfs in May or June (Spokane County, 2001c).
Historically peak flows have exceeded 45,000 cfs (USGS, 2001). Low
streamflows are a problem in summer and affect water quality. During
low flows, streamflows are regulated by operation of the Post Falls Dam,
operated by Avista Utilities. Avista's agreement with the State of
Idaho to maintain the level of Lake Coeur d'Alene limits the amount of
flow released to the Spokane River. Ecology has recommended minimum
flows for the Spokane River based on Washington Department of Fish and
Wildlife recommendations, but they have not been adopted as an
administrative rule. The recommended flows are 2,000 cfs at the Spokane
gage.
Little Spokane River.
The Little Spokane River flows into the Spokane River at Long
Lake, approximately 5 miles north of the Spokane city limits. The
Little Spokane is headwatered in Pend Oreille County near Newport. It
is joined by the West Fork just south of the Spokane County border. The
lower segment of the Little Spokane River is designated as a state
scenic river. This designation is less strict than a federal Wild and
Scenic River designation, but still places restrictions on activities
near the designated segment, particularly for the location of dangerous
waste management facilities or the discharge of any hazardous
substances.
Streamflows on the Little Spokane are measured at the U.S. Geological
Survey (USGS) gage at Dartford. Streamflows typically range from 300
cfs to 700 cfs. Summer flows on the Little Spokane are supplied almost
completely by groundwater discharges to the river. Summer flows in the
river have been declining since the 1950s, due to surface and
groundwater withdrawals and diversions (Washington Department of
Ecology, 1995). In 1975, Ecology closed the Little Spokane Basin to
further water appropriations because of concerns about water
availability and developed a management plan for the river. All water
rights issued since then have been conditioned to specific base flows.
A base flow of 115 cfs from July 1 to September 15 at the Dartford gage
is established by administrative rule in WAC 173-555. According to
Ecology, streamflows at the Dartford gage do not meet minimum flow
requirements approximately 15 percent of the time (Washington Department
of Ecology, 1995). Streamflows at the downstream Rutter Parkway gage
are significantly higher because of recharge from the Spokane Aquifer.
Figure 4. Spokane Area Water Resources
Latah (Hangman) Creek.
Latah Creek flows into the Spokane River on the west side of the city.
The creek originates in Idaho and flows northwest to the Spokane River.
Flows on Latah Creek fluctuate between a low of 30 cfs in summer to
peaks of 2,000 cfs in winter.
Permeable soils and the glacial history of the area have created
numerous groundwater aquifers in the area (See Figure 5). The largest
of these aquifers is the Spokane Valley-Rathdrum Prairie Aquifer
(Spokane Aquifer), which extends from Lake Pend Oreille through the
Spokane Valley. Other aquifers in the area are the Deer Park Aquifer,
the Little Spokane Aquifer, the Green Bluff, Peone Prairie, and
Orchard-Pleasant Prairie Aquifers, and the East Columbia Plateau
Aquifer. The latter includes the West Plains Aquifer.
The Spokane Aquifer is the primary source of
drinking water for more than 400,000 people in Idaho and Washington. In
1978 the Environmental Protection Agency (EPA) designated the Spokane
Valley-Rathdrum Aquifer as a "sole source" aquifer under authority of
the Safe Drinking Water Act.
Connectivity. The
Spokane-Rathdrum Prairie Aquifer is hydraulically connected to the
Spokane and Little Spokane Rivers. At times the rivers gain flow from
the aquifer; at other times the aquifer gains flow from the rivers (see
Figure 6). The hydraulic connectivity significantly affects streamflows
and the level of the aquifer and can affect water quality of both the
aquifer and the rivers. Connectivity is a key element in the evaluation
of potential water rights for withdrawals from the Spokane Aquifer.
The Spokane River loses large quantities of water to the aquifer in the
Spokane Valley. Recent studies indicate that more than 140 cfs is lost
to the aquifer between Post Falls Dam and Barker Road. On the Little
Spokane River, groundwater inflow to the river represents nearly the
entire discharge to the river above the Dartford gaging station. Below
the Dartford station, streamflow increases due to groundwater inflow
from the Spokane Valley-Rathdrum Aquifer.
Hydraulic connectivity is most significant during summer low-flow
periods. During summer it is estimated that up to 80 percent of
streamflow in the Spokane River is aquifer discharge, whereas in the
winter only 20 percent of streamflow is aquifer discharge (Miller,
1996). There is still much uncertainty about the hydrology of the
region and the amount of water exchange that occurs between the rivers
and the aquifer.
Floodplains. The Federal
Emergency Management Agency (FEMA) maps flood prone areas for cities and
counties based on calculation of the 100-year flood--a flood with a 1
percent statistical probability of occurring in any given year. Major
floodplains in the Spokane area are located along the shores of lakes,
the Spokane River, and Little Spokane River. Within the planning area
for the wastewater treatment plant, floodplain areas are limited to the
area immediately adjacent to the Spokane River.
Water quality issues in the Spokane area involve both surface and
groundwater resources. Several segments of the Spokane and Little
Spokane Rivers have been placed on the federal Clean Water Act Section
303(d) list of impaired water bodies. Because the Spokane Aquifer is
unconfined, it can be easily contaminated. Any contamination poses a
threat to the sole source of drinking water for the region.
Water bodies are included on the 303(d) list because water quality does
not meet state standards and technology based controls are inadequate to
achieve those standards. The Department of Ecology's (Ecology) 303(d)
list for the Spokane River includes the constituents arsenic, cadmium,
chromium, dissolved oxygen, lead, PCBs, sediment bioassay, and zinc.
Cadmium, lead, and zinc concentrations often exceed state water quality
standards at the state border. The source of these contaminants is
attributed to the discharge of heavy metals at the Bunker Hill Superfund
site on the South Fork Coeur d'Alene River, which discharges to Lake
Coeur d'Alene. Much of the metal loading reaching Washington is from
the resuspension of sediment deposited outside the designated Bunker
Hill Superfund site. For 303(d) water bodies, the state must develop
Total Maximum Daily Loads (TMDL) or maximum limits on the amounts of
pollutants that can be discharged to a water body and allow that water
body to meet water quality standards. Ecology has established TMDLs on
the Spokane River for phosphorous and metals (cadmium, lead, and zinc)
and is considering a TMDL for dissolved oxygen in Long Lake and the
Spokane River. Segments of the Little Spokane River have been placed on
the 303(d) impaired list for the constituents fecal coliform, PCBs, pH,
and temperature. No TMDLs have been established for the Little Spokane
River.
Figure 5. Spokane Area Aquifers
Figure 6. Hydraulic Connectivity
Because of its sole source aquifer listing, water quality in the Spokane
Aquifer has been monitored for over 20 years. During this time, aquifer
water quality has generally been good to excellent. There have been
less than 50 violations of drinking water standards. During the mid
1980s, water quality declined slightly in terms of inorganic indicators
like nitrate-nitrogen and chloride. The decline was attributed to
increased development and associated septic tanks and drainfields.
These water quality indicators improved steadily in the late 1980s and
1990s as sewer construction increased to replace septic tanks. Septic
tanks continue to be a contributor to local declines in water quality.
Other potential sources of groundwater contamination in the region have
been identified and include stormwater injection through dry wells;
chemical storage, transport, and accidental spills; improperly abandoned
wells; leakage from underground pipelines and sewers; over-application
and spillage of fertilizers; application of road de-icing compounds;
leakage from above ground or underground fuel storage tanks and
pipelines; improper waste disposal in excavations; sanitary landfills;
and gravel pit mining.
Watershed Planning. Three
of four WRIAs covering the Spokane River Basin are involved in watershed
planning. Watershed planning for the Middle Spokane and Little Spokane
Rivers (WRIAs 55 and 57) is being conducted jointly. Watershed
assessment and development of a water budget for the combined basins
has begun. Water quality, an optional planning component, is also being
addressed in the watershed planning process for WRIAs 55 and 57. Water
quality is being evaluated as it relates to flows.
Latah Creek is located in WRIA 56. The Latah Creek Planning Unit has
completed the Phase 2 work plan and watershed assessment began in early
2001. The Latah Creek Planning Unit has accepted the optional
components of water quality, instream flow, and fish habitat. No lead
agency has been established for WRIA 54, the Lower Spokane River.
Proposed Water and Effluent Quality
Standards. A preliminary assessment has been made of likely
effluent quality requirements for discharge of wastewater to the Spokane
River based on state water quality standards and seasonal
characteristics of the river (Spokane County, 2001c). These potential
requirements are shown in Table 5. Discharge requirements will be
established by Ecology during the NPDES permitting process. The
permitting process requires the County to demonstrate that effluent
discharge will allow the receiving waters to meet water quality
standards.
The summer low-flow period is the most critical for water quality;
therefore, Ecology typically establishes seasonal permit limits for
wastewater discharges. The more stringent requirements are in summer.
The potential discharge requirements shown in Table 5 reflect the need
for more strict requirements in summer.
Table 5. Anticipated Effluent Quality
Requirements for New Surface Water Discharges for the Spokane River
(Monthly Average Values Unless Noted Otherwise).
|
Parameter |
Summer |
Winter |
|
BOD (mg/L)1 |
10-20 |
30 |
|
Total Suspended Solids (mg/L) |
30 |
30 |
|
Ammonia-Nitrogen (mg/L)1,2 |
1-2 |
4-8 |
|
Total Nitrogen (mg/L) |
No limit |
No limit |
|
Total Phosphorous (mg/L)1,3 |
0.3-0.6 |
No limit |
|
Dissolved Oxygen (mg/L)1 |
>6.0 |
No limit |
|
Fecal Coliform (cfu/100 mL) |
200 |
200 |
|
Chlorine Residual (µg/L)2 |
~8 |
~ 8 |
|
pH (s.u.)4 |
6.0-7.8 |
6.0-7.8 |
|
Lead (µg/L)5 |
~ 2 |
~2 |
|
Zinc (µg/L)5 |
~ 60 |
~ 60 |
|
Cadmium (µg/L)5 |
~ 0.2 |
~ 0.2 |
SOURCE: Draft Wastewater Facility
Plan; Spokane County, 2001b.
1 Required value will be defined by
dissolved oxygen TMDL process.
2 Required value will be defined by
mixing zone study for toxicity.
3 Required value will be defined
through negotiation with Phosphorous TAC.
4 Instantaneous value.
5
Required value will be defined based on monitoring of actual
effluent metals concentration.
3.2.2.1
Construction
All alternatives except the No Action Alternative would have similar
construction related impacts to water resources. Alternative 5, No
Action, would require no construction and thus would have no
construction related impacts. Alternative 1 would require construction
near the river to expand the existing SAWTP. Alternatives 2, 3, and 4
would require construction of new plants on new sites. Construction
impacts to water resources at these location(s) would depend on the
proximity of the sites to surface water bodies. If the plant location(s)
are near surface water bodies, construction could generate increased
runoff and sedimentation that could affect water quality. It is likely
that construction of a new outfall for discharges to the river will be
required for Alternatives 2, 3, and 4. New outfall construction will
require in-water work, and could affect water quality during
construction. Because of the depth to groundwater, it is unlikely that
construction of the new treatment plants or expansion of the SAWTP would
require dewatering.
Alternatives 1 through 4 would require the construction of additional
conveyance facilities. Alternative 1 will require the largest amount of
construction to install an 8-mile forcemain and two pumping stations
through an urban area. Conveyance facilities for Alternatives 2, 3, and
4 will also involve forcemain and pumping station construction, but on a
smaller scale than Alternative 1. Runoff from construction of these
facilities could impact nearby water bodies. Conveyance construction for
Alternative 1 will require a crossing of the Spokane River. The river
crossing work could require in water construction.
3.2.2.2
Operation
The wastewater treatment facilities proposed under all the alternatives
could generate operational impacts on nearby water bodies. Expansion of
the SAWTP under Alternative 1 and construction of new treatment plants
under Alternatives 2, 3, and 4 would increase the amount of effluent
discharged to the Spokane River. The County is considering alternatives
that would reduce the amount of effluent discharged (See Section 3.9.2);
however, the majority of effluent will be discharged to the Spokane
River. For all alternatives, effluent discharges would meet the
standards of the NPDES permit negotiated with the Department of
Ecology.
It is anticipated that effluent quality requirements will be based on
the requirements presented in Table 5, but will be refined based on the
exact location of the discharge, results of mixing zone studies,
effluent concentrations of metals, results of a dissolved oxygen TMDL
Study, and negotiations with the Phosphorous Technical Advisory
Committee. Preliminary modeling indicates that near-field
dissolved oxygen (DO) levels will be 0.2 mg/L or less. This level of
impact is allowable in stretches of the river where natural conditions
prevent instream water quality from being met. The stretch of river
being considered for the discharge point has a naturally low level of DO
from groundwater recharge. The effluent discharge will not violate
temperature criteria. The water quality criteria for lead, cadmium, and
zinc are already exceeded on the Spokane River. The County anticipates
receiving a performance based effluent limit to avoid worsening the
condition. In order to ensure that the metals concentrations in the
effluent are low, the County will focus on identifying industrial
discharge sources and requiring aggressive pretreatment to remove metals
before discharges reach the County's waste stream. The new plant will
not use chlorine disinfection; therefore, there will be no chlorine
toxicity problems. Modeling indicates that the ammonia-nitrogen
concentration will be below ammonia toxicity criteria. The effluent is
not expected to contain PCBs since the City of Spokane has not detected
PCBs in the effluent from the SAWTP. The assessment of far-field
impacts will require more detailed modeling than can be performed at
this time; however, it is anticipated that the new plant will produce
low concentrations of DO consuming constituents such as biochemical
oxygen demand (BOD) and ammonia. The effluent will also contain low
levels of phosphorous which can lead to primary production activity
downstream.
Alternative 1, expansion of the SAWTP, would concentrate effluent at one
location on the river and could make meeting water quality standards
difficult. Alternatives 2, 3, and 4 would allow greater dispersal of
effluent discharges. Alternative 4 would provide the greatest effluent
dispersal with the use of two smaller plants. Alternative 2 would
provide greater dispersal than Alternative 3 because it would be located
at a greater distance from the SAWTP and effluent would be discharged in
the section of the river below Upriver Dam. Discharge to the reach
below Upriver Dam provides several advantages over other discharge
points on the river. The reach is located on a gaining stretch of the
river and would reduce the potential for discharge to the aquifer or
migration of effluent into the aquifer. This reach of the river
provides good separation from the SAWTP discharge. The reach is located
downstream of the discharge points for Inland Empire Paper, Kaiser, and
Liberty Lake, and would require consideration of those discharges in
NPDES negotiations.
Under Alternative 1, the SAWTP site is projected to have adequate space
for expansion to handle predicted wastewater flows through 2025. The
SAWTP will be expanded to 65 mgd in the 2020 horizon. The site would
then be at maximum capacity and could not be expanded on site to handle
additional flows from the City or County.
Groundwater quality would improve under all the action alternatives.
Currently, wastewater is leaching into the aquifer though septic tanks.
The County’s Septic Tank Elimination Program requires increased
treatment plant capacity to handle the increased volume of flows
generated by new connection to the wastewater treatment system.
Alternatives 1 through 4 all provide expanded capacity and would allow
the County to continue to improve groundwater quality through its Septic
Tank Elimination Program.
None of the alternatives are expected to have significant impacts on
water quantity in the Spokane River. All the action alternatives would
increase effluent discharges to the Spokane River by 34 cfs in 2025 and
42 cfs in 2050. This is approximately 3 percent of the average summer
flow of 1,400 cfs and an even smaller percent of winter peak flows. The
increased discharges are not expected to affect the hydrology of the
river.
Construction in a flood-prone area could subject the treatment plant to
damage that could make the plant inoperable during a flood event. The
treatment plant structures could also impede floodwaters and block flow,
increasing flood damage.
Water quality impacts would be unacceptable under Alternative 5, No
Action. If no new treatment plant were constructed, the county would
exceed its 10 mgd capacity at the SAWTP by 2007. The County would be
unable to provide adequate capacity for projected growth within the
planning area. This could result in building moratoriums, fines for
violation of water quality standards, and possible imposition of
judicial control to regulate water quality. The County would also be
unable to continue its Septic Tank Elimination Program. This could
result in declines in groundwater quality of the Spokane Aquifer.
3.2.3.1
Construction
Construction of the wastewater treatment facilities could lead to
increased erosion and sedimentation that could impact adjacent water
bodies. Erosion and sedimentation control measures suitable for the
selected site would be included as part of project design and
construction to minimize sedimentation. Spokane County will require
that a comprehensive erosion and sediment control plan be developed
prior to construction. At a minimum the plan would include elements for
site stabilization, slope protection, drainageway protection, and
sediment retention. All construction activity would be required to use
best management practices to minimize erosion and sedimentation
impacts. The project would also be required to comply with conditions
of the NPDES general permit for construction issued by Ecology. A spill
control plan to prevent fuel, chemical, or other pollutant spills from
reaching any surface water bodies or seeping into groundwater will be
developed. For any in water work, including stream crossings and
installation of the outfall diffuser, the requirements of the WDFW
Hydraulic Project Approval (HPA) will be implemented.
Dewatering may be required for construction of a new treatment facility
or expansion of the existing SAWTP. During construction, groundwater
that might enter excavations and trenches would be controlled to protect
the quality of foundations and fill materials. To protect water quality
in the Spokane Aquifer and any adjacent water bodies, groundwater
collected from excavations would be drained to a stormwater treatment
and collection system before discharge. A dewatering plan would be
developed to monitor groundwater withdrawal and avoid groundwater
contamination.
3.2.3.2
Operation
The intent of the Wastewater Facility Plan is to improve water quality
management in Spokane County. Increased wastewater treatment capacity
will prevent potential wastewater problems in the river and allow the
County to continue its Septic Tank Elimination Program to prevent
aquifer contamination. Effluent limitations will be set through
negotiations with Ecology for the NPDES. Operation of the treatment
plant will enhance overall water quality.
Potential impacts, if the plant were to be located in a flood-prone
area, could be mitigated by the following measures, some of which are
provided as conditions of treatment plant construction in a shoreline
area by the County Shoreline Program:
·
Locating as many of the treatment facilities as possible above
the flood level;
·
Insuring that facilities do not obstruct or impede the flow of
floodwaters; and
·
Designing facilities so that they are protected from damage and
will continue to function during flooding.
3.3
Environmental Health
This section discusses environmental health issues (e.g., noise, reuse
of reclaimed water, and biosolids utilization) associated with the
Spokane Wastewater Treatment Facility.
3.3.1.1
Noise
Noise sources in the Spokane Valley area consist of urban downtown,
urban residential, suburban residential, and industrial. The Interstate
90 (I-90) corridor is located approximately through the middle of the
City of Spokane and contributes to the ambient noise levels in the
vicinity. There are two major railroad corridors through the City and
the Mid-Valley. More than 50 trains per day use the tracks and are a
major source of noise.
Noise Overview. The human
ear responds to a wide range of sound intensities. The decibel scale
used to describe sound is a logarithmic rating system that accounts for
the large differences in audible sound intensities. This scale accounts
for the human perception of a doubling of loudness as an increase of 10
decibels (dBA). Hence, a 70 dBA sound level will sound twice as loud as
a 60 dBA sound level. People generally cannot detect differences of 1
dBA; under ideal laboratory conditions, differences of 2 or 3 dBA can be
detected. A 5 dBA change would be expected to be perceived under normal
conditions. Table 6 shows representative sounds and corresponding noise
levels produced in decibels.
When addressing the effects of noise on people, it is necessary to
consider the frequency response of the human ear. Instruments are
therefore designed to respond to or ignore certain frequencies. The
frequency-weighting most often used is A-weighting; measurements from
instruments using this system are reported in “A-weighting decibels” or
dBA. All sounds in this discussion are reported in dBA.
Factors affecting the impact that a given noise will have on a person
include frequency and duration of the noise, the absorbency of the
ground and surroundings, and the distance of the receptor from the noise
source. The receptor and the usual background noise levels also
determine the degree of impact.
Relevant Local, State, and Federal
Noise Standards and Guidelines. Spokane County has not
developed and adopted its own noise regulations. The County follows the
State of Washington noise regulations per WAC 173-60. The following
table shows the maximum permissible environmental noise levels based on
the EDNA of a particular noise source. EDNA is defined as "the
Environmental Designation for Noise Abatement, being an area or zone
(environment) within which maximum permissible noise levels are
established."
Table 6. Sound
Levels Produced by Common Noise Sources
|
Thresholds/Noise Sources |
Sound
Level (dBA) |
Subjective Evaluations |
Possible Effects on Humans |
|
Human Threshold of Pain
Carrier jet takeoff (50 ft) |
140 |
Deafening |
Continuous exposure can cause hearing damage |
|
Siren (100 ft)
Loud rock band |
130 |
|
Jet takeoff (200 ft)
Auto horn (3 ft) |
120 |
|
Chain saw
Noisy snowmobile |
110 |
|
Lawn mower (3 ft)
Noisy motorcycle (50 ft) |
100 |
Very Loud |
|
Heavy truck (50 ft) |
90 |
|
Pneumatic drill (50 ft)
Busy urban street, daytime |
80 |
Loud |
|
Normal automobile at 50 mph Vacuum
cleaner (3 ft) |
70 |
Speech Interference |
|
Large air conditioning unit (20 ft)
Conversation (3 ft) |
60 |
Moderate |
|
Quiet residential area Light auto
traffic (100 ft) |
50 |
Sleep Interference |
|
Library Quiet home |
40 |
Faint |
|
Soft whisper (15 ft) |
30 |
Minimal Effects |
|
Slight Rustling of Leaves |
20 |
Very
Faint |
|
Broadcasting Studio |
10 |
|
Threshold of Human Hearing |
0 |
Source: US Environmental Protection Agency, 1971.
Note that both the subjective evaluations and the physiological
responses are continuums without true threshold boundaries.
Consequently, there are overlaps among categories of response that
depend on the sensitivity of the noise receivers.
Spokane County has established restrictions on noise levels during
nighttime hours. Spokane County Code restricts construction activities
to the hours between 7 a.m. and 10 p.m. during which time construction
noise(s) are exempt from the provisions of Section 6.10.010 – Noise
Disturbances Prohibited. (Section 6.12.020 – Exemptions).
The City of Spokane also follows the State of Washington Maximum
Permissible Environmental Noise Levels (Table 7) and has restrictions on
noise levels during specific time periods:
"No person may make or permit any unnecessary or unusual noise between
the hours of 6 a.m. and 10 p.m. to the annoyance of others. No person
may make or permit, in the operation of a machine, in the harboring of
an animal or otherwise, any noise between the hours of 10 p.m. and 6
a.m. to the annoyance of any other person of ordinary sensibilities"
(Spokane Municipal Code, 10.08‑020 – Noise).
Table 7. Maximum
Permissible Environmental Noise Levels
|
EDNA of Noise Source |
EDNA of Receiving Property |
|
|
Class A |
Class B |
Class C |
|
Class A |
55 dBA |
57 dBA |
60 dBA |
|
Class B |
57 |
60 |
65 |
|
Class C |
60 |
65 |
70 |
Source: WAC 173-60-040
Hazardous Waste. A review
of hazardous waste site databases has revealed numerous hazardous waste
sites, including Superfund sites, within the City of Spokane and Spokane
County properties east of the city limits. The databases reviewed
include:
·
EPA's Comprehensive Environmental Response, Compensation, and
Liability Act (CERCLA) Information System CERCLIS
·
EPA's National Priorities List (NPL)
·
EPA's EnviroFacts Warehouse Web site databases
·
Ecology's Toxic Release Inventory (TRI)
·
Ecology's Resource Conservation and Recovery Information
System (RCRIS)
Site-specific database searches and site assessments would be performed
during the site selection process.
Some hazardous waste sites have leached contaminants to soils and
groundwater, but contamination tends to be localized; in a few
instances, the contaminated groundwater plume has migrated and poses a
potential health hazard. See the Groundwater Section for additional
detail on groundwater contamination in the project area.
Reclaimed Water and Biosolids.
Reclaimed water and biosolids are discussed in Section 3.9.2,
Effluent End Use, and Section 3.9.3 Biosolids Management.
Short-term impacts related to noise would be similar for Alternatives 2
through 4. Construction noise would include excavation activities and
machinery, heavy trucks, miscellaneous construction machinery (including
pile drivers), and workers' vehicles. Excavation activities would have
the greatest impact to noise levels in the vicinity of the treatment
plant construction. Excavation would include digging and scraping of
the soil by heavy machinery, and dumping of soil into the beds of heavy
trucks for removal from the construction site. Construction activities
could last up to two years for the construction of a new treatment
facility, with excavation activities occurring during the initial phase
of construction. Construction activities associated with expansion of
the existing SAWTP (Alternative 1) would also last approximately two
years.
There is potential for the presence of hazardous substances on a given
treatment facility site. The degree of likelihood depends upon many
factors, including previous uses. A complete site assessment would be
performed prior to commencement of any construction activity. Impacts
from hazardous substances for Alternatives 1 through 4 are not expected
to be significant, because site remediation activities would occur prior
to any construction. No impacts associated with Alternative 5 would
occur as no construction activities would take place.
Construction of a conveyance system would not be expected to encounter
any hazardous substances because the conveyance routes will primarily
follow existing roadways. Roadway beds would have previously been
examined during road and/or other utility construction. Hazardous
substances could be encountered during construction of pump stations or
the outfall. No long-term impacts associated with hazardous substances
are expected for Alternatives 1 through 4 as a result of conveyance
system, pump station, or outfall operation.
Conveyance system and outfall construction would result in short-term
noise impacts to surrounding properties. Noise sources would include
heavy trucks and machinery, workers' vehicles, and voices. The impacts
to any given section would be temporary and short in duration, as
construction activities move along the length of the route rather than
remain in a single area. Short-term noise impacts are therefore not
expected to be significant. No significant, long-term adverse impacts
from noise are expected as a result of installation of a new conveyance
system or outfall. Some noise would be generated at pump stations, but
is expected to be minor. Pump stations would be housed in sound-proofed
structures to minimize or eliminate noise.
The degree of significance related to noise impacts for all build
alternatives would be dependent upon final site and conveyance route
selection. Noise impacts would be greatest in residential areas or
where construction activities occur near a sensitive receptor (e.g.,
nursing home, school).
Long-term noise impacts associated with Alternative 1 would be similar
to the existing conditions at the SAWTP facility. Any increase in noise
associated with an expanded treatment plant is expected to be
negligible.
Long-term noise impacts associated with Alternatives 2 through 4 would
be similar and would include workers' vehicles, heavy trucks for
biosolids pick-up and disposal, on-site machinery, and voices.
Because any hazardous substances present on a given site would be
removed and the site remediated prior to operation of a treatment plant,
no long-term impacts associated with hazardous substances are
anticipated.
The existing SAWTP uses chlorine for disinfection, sulfur dioxide for
dechlorination, and alum for phosphorous removal and would continue to
use these chemicals for up to 10 to 15 years. Chemical disinfection
will be replaced by UV disinfection within this 10 to 15 year period.
No significant adverse impacts are expected as a result of chemical use
under Alternative 1.
Alternatives 2 through 4 would incorporate UV disinfection as part of
plant design. A small amount of hypochlorite would be kept on site for
process control functions. Therefore, no significant adverse impacts
are expected as a result of the use of chemicals for Alternatives 2
through 4. Water quality degradation as a result of the No Action
Alternative could result in environmental health impacts through
increased discharges of toxic materials.
Mitigation measures for noise impacts would include housing noisy
machinery in sound-proofed structures and keeping workers' vehicles and
heavy trucks in good working order. In addition, construction
activities would occur between the allowable construction hours (6 a.m.
to 10 p.m. for the City of Spokane, and 7 a.m. to 10 p.m. for Spokane
County).
Mitigation measures associated with hazardous substances would include a
thorough site assessment and remediation (if necessary) for a given site
prior to commencement of any construction activities.
Use of hazardous substances at the treatment plant would occur in
accordance with local and state standards and guidelines. Transport,
handling, and storage would comply with all applicable regulations to
insure the safety of facility workers as well as residents or workers at
nearby properties. Material Safety Data Sheets (MSDS) would be made
available to all employees at the treatment plant and appropriate
training for anyone handling chemicals would be required.
Impacts and mitigation related to use of reclaimed water and biosolids
are discussed in Section 3.9.2, Effluent End Use, and Section 3.9.3,
Biosolids Management.
The following section describes the plants and animals in the project
area with an emphasis on those that are listed as threatened,
endangered, or candidate species by the state or federal government, and
on state sensitive species. Impacts of each of the proposed
alternatives on plants and animals are discussed.
Habitat within Spokane County ranges from shrub-steppe in the lower
scabland areas to subalpine mountainous area. This habitat diversity
supports a wide variety of plant species and wildlife. The project area
is located in the Urban Growth Area (UGA) surrounding the City of
Spokane. This area has been mostly developed, but contains small
undeveloped areas.
In 1996 Spokane County adopted its Critical Areas Ordinance (Spokane
County Code 11.20) (Spokane County, 1996). The Ordinance designated and
mapped critical fish and wildlife habitat areas. There are few Critical
Areas within the County's draft UGA (Spokane County, Draft Comprehensive
Plan 2000a). Fish and Wildlife Critical Areas within the UGA include
white tailed deer, urban natural open space, riparian areas, and
wetlands. The City of Spokane adopted its Critical Areas Ordinance in
1994.
Prior to construction of Grand Coulee Dam, several types of anadromous
fish migrated through the Spokane River and spawned in the river and its
tributaries. Access to the Spokane River has been blocked since the
1940s. Consequently, there are no threatened or endangered anadromous
species in the project area. The Washington Department of Fish and
Wildlife's (WDFW) Priority Habitat and Species (PHS) maps for the
project area indicate that the Spokane and Little Spokane Rivers are
priority habitats for resident fish (WDFW, 2001). The U.S. Fish and
Wildlife Service (USFWS) list of threatened and endangered species for
the project area does not list any fish species (USFWS, 2001). See
Appendix A for species letters.
The USFWS lists bald eagle (Haliaeetus leucocephalus), Ute
ladies'-tresses (Spiranthes diluvialis), and water howellia (Howellia
aqautilis) as threatened species that may occur in the vicinity of
the project (USFWS, 2001). In addition, Spalding's silene (Silene
spaldingii) is proposed as a threatened species. The PHS maps do
not indicate that any of these listed species are located in the project
area. Bald eagles have been reported in the City of Spokane (City of
Spokane, 1996). It is unlikely that the listed plant species would be
found in the project area; however, site specific surveys would be
required.
The PHS maps indicate that priority habitat areas for the following
species are found in the project area:
Bird Species: merlin, osprey, peregrine falcon, pileated woodpecker,
great blue heron, and mountain quail, and
Butterfly species: Compton tortoiseshell and thicket hairstreak.
The butterfly species are listed as monitor species by WDFW. In
general, the priority habitats for bird species are located along the
Spokane River and the butterfly habitat is located in the hills north
and south of the river. One area of Compton tortoiseshell habitat is
found along the river. The mountain quail are located in upland habitat
south of the Spokane River.
Construction related impacts would be the same for all the alternatives
except Alternative 5, which would involve no construction and have no
impacts. All of the action alternatives, including expansion of the
existing city plant under Alternative 1, would involve construction
activities that could cause temporary disturbances to animal species.
Clearing and grading would remove vegetation and potentially cause birds
and small mammals to relocate. Similarly, construction related noise
could cause birds and mammals to relocate during construction.
Construction could generate increased runoff and erosion from treatment
plant areas. If the sediment is allowed to reach waterways, it could
impact fish habitat.
Operational impacts of all the action alternatives on plant and animal
species are expected to be minimal. Each of the treatment plants will
generate noise that could disturb animal species. Effluent discharges
could degrade water quality in the Spokane River and adversely impact
fish species, but effluent will be treated to meet Ecology’s specified
permit limits. The increased impervious surface created by construction
of the treatment plant(s) could increase runoff to the river, but should
not affect river hydrology because stormwater flows will be small
relative to river flows. The No Action alternative could impact aquatic
species through water quality degradation.
Potential mitigation measures for impacts to plant and animal species
would include measures to reduce construction impacts and design
measures to reduce operational impacts. Prior to construction under any
action alternative, each proposed site would be evaluated to determine
the presence of threatened, endangered, or sensitive species.
Construction contractors would be required to follow best management
practices to minimize noise and erosion. A Temporary Erosion and
Sedimentation Control Plan (TESCP) would be developed for construction.
The minimum amount of vegetation would be removed during construction
and following construction, the treatment plant would be landscaped
using native and/or exotic species. The treatment plant would meet the
water quality standard requirements of the NPDES permit.
This section discusses energy and natural resources issues (e.g.,
wastewater treatment facility components requiring energy resources)
associated with the Spokane Wastewater Facility Plan.
Avista Utilities (Avista), formerly Washington Water Power, provides
natural gas and electricity to the City of Spokane and outlying areas in
unincorporated Snohomish County. Avista receives electricity from the
Bonneville Power Administration’s (BPA) federal power grid. Electricity
is also available through electricity generation facilities within city
limits (Ehrbar, personal communication, 2001). Various private
electricity distributors serve the greater Spokane area outside of the
Urban Growth Boundary (UGB).
Increased energy capacity is anticipated to accommodate the City of
Spokane Comprehensive Plan’s proposed future land uses. Expansions will
be required at existing substations located at Francis, Cedar, and
Sunset, and new substations will be needed in Mead and the Indian Trail
area (City of Spokane, 2000).
Wastewater facility components and/or processes that use electricity
include pumping mechanisms, mechanical aeration, sludge processing
systems, blowers, and solids-handling systems. Motor driven equipment
including pumps, fans, and compressors would also likely require
additional energy sources. In addition to these major electricity
users, a variety of other plant, pump station, and accessory facilities
require electricity.
All of the alternatives except for the No Action Alternative would have
similar short-term impacts to energy during the construction phase.
With the expansion of the existing SAWTP (Alternative 1) or the
construction of new wastewater treatment facilities (Alternatives 2, 3,
and 4), the major consumer of energy will be construction vehicles that
will require fuels during the construction and excavation phases.
Energy impacts associated with construction would include consumption of
fossil fuels, electricity, and possibly natural gas. Energy consumption
would depend generally on the duration of construction.
Energy use for all of the alternatives will vary according to the
capacity of each of the wastewater treatment facilities for Alternatives
1, 2, 3, and 4. The effluent end use alternatives will have significant
energy requirements associated with pumping. Another high energy user
in terms of the wastewater facility operation involves the alternatives
that would use reverse osmosis for groundwater recharge. Table 8 lists
some of the components of a wastewater treatment facility and estimated
electricity use by kilowatt-hours per day (kWh/d).
Because Alternatives 1, 2, 3 and 4 will all in effect discharge an
average flow of 21.9 mgd, there is not a significant difference in
energy use between these proposed alternatives. However, higher energy
costs will be attributed to alternatives that require greater pumping.
Alternative 1 would require the construction of two new pump stations
and Alternative 2 would require one new pump station. Alternatives 3
and 4 would also require the construction of new pump stations; however,
an exact number is unknown at the time of this document’s production.
Also, depending on the size of the wastewater treatment facility, energy
efficiency (per mgd) would increase slightly as the plant size
increases.
Table 8.
Electricity Requirements for Advanced Wastewater
Treatment Plants Without Nitrification.
|
Electricity
Use, kWh/d |
|
Item |
5-mgd plant |
10-mgd plant |
20-mgd plant |
|
Wastewater Pumping |
716 |
1,402 |
2,559 |
|
|
2 |
2 |
3 |
|
Aerated Grit Removal |
87 |
134 |
250 |
|
Primary Clarifiers |
78 |
155 |
310 |
|
Aeration (Diffused Air) |
2,660 |
5,320 |
10,640 |
|
Return Sludge Pumping |
213 |
423 |
724 |
|
Secondary Clarifiers |
78 |
155 |
310 |
|
Chemical Addition |
290 |
552 |
954 |
|
Filter Feed Pumping |
445 |
822 |
1,645 |
|
Filtration |
247 |
385 |
709 |
|
Gravity Thickening |
15 |
25 |
37 |
|
Dissolved Air Flotation |
n/a |
2,022 |
3,268 |
|
Aerobic Digestion |
2,400 |
n/a |
n/a |
|
Anaerobic Digestion |
n/a |
1,400 |
2,700 |
|
Belt Filter Press |
228 |
457 |
689 |
|
Chlorination |
5 |
27 |
53 |
|
Lighting and Buildings |
400 |
800 |
1,200 |
|
TOTALS |
7,864 |
14,081 |
26,051 |
|
Unit Electricity Use (kWh/million
gallons) |
1,573 |
1,408 |
1,303 |
Water Environment Federation, 1997.
Under each proposed alternative, methane gas will be produced and will
be recovered as an additional energy source.
Under all alternatives, most pump stations that will be in operation
will be variable speed to facilitate flow variations without building
large wetwells or causing flow surges to the treatment plant.
Well-designed variable speed systems are very energy-efficient.
Alternative 5, the No Action Alternative, would have the least impact on
energy consumption in the project area.
3.5.3
Mitigation
With either the expansion of the existing SAWTP (Alternative 1) or the
construction of new wastewater facilities (Alternatives 2, 3, and 4),
the use of energy efficient construction equipment could be required by
the contractors. This would include the use of the most fuel-efficient
construction equipment.
Many features that increase energy efficiency at a wastewater treatment
plant can be incorporated or specified during plant design. The County
could require that these features be evaluated during the design phase.
This section discusses the current air quality conditions in the City of
Spokane and Spokane County area to the east of the city limits.
Applicable state and local regulations are summarized. Impacts to air
quality and mitigation associated with a new treatment plant facility
are discussed.
Over the past 25 years, air quality in the City of Spokane has improved
substantially from the heavily polluted situation in the 1970s.
However, Spokane is currently classified as a serious nonattainment area
for carbon monoxide and a moderate nonattainment area for fine
particulate matter (particulate matter up to 2.5 micron in diameter [PM2.5])
(Spokane County Air Pollution Control Agency (SCAPCA), 2001a).
According to the Department of Ecology's 1999 Air Quality Trends in
Washington, the trend for carbon monoxide and fine particulate
matter observations above federal standards has been a steady decline
towards zero reports per year (Ecology, 1999). According to SCAPCA's
Air Quality Index information (SCAPCA, 2001b), there were only two days
in 2000 where the air quality within Spokane County was rated as
"Unhealthy for Sensitive Groups." No Unhealthy, Very Unhealthy, or
Hazardous days were reported for the year 2000. As of February 2001, no
unhealthy days have been reported in 2001 (SCAPCA, 2001b).
SCAPCA has implemented an air quality maintenance plan to have the area
redesignated from nonattainment to attainment status (SCAPCA, 2001a).
In addition, Spokane County has included air quality as a component of
the Natural Environment chapter of its Comprehensive Plan. This
document sets goals and policies that are designed to maintain or
improve visibility and air quality in Spokane County (Spokane County,
2000a).
Construction-related impacts to air quality would be generally the same
for Spokane County wastewater treatment facility Alternatives 1 through
4. Construction impacts would include dust from construction
activities, asphalt fumes from paving operations, and vehicle exhaust
from construction equipment, heavy trucks, and workers' vehicles.
People in passing vehicles, or residents or workers at nearby properties
may detect odors at intermittent points during the construction period.
Because these impacts would occur intermittently during the allowable
construction hours between 7 a.m. and 10 p.m. (Spokane County Code,
Section 6.12.020, Exemptions) and for the period of construction only
(approximately two years for Alternatives 1 through 4), they are not
anticipated to be significant. No construction impacts to air quality
would occur as a result of Alternative 5.
Short-term impacts to air quality would include dust from construction
conveyance system activities, asphalt fumes from paving operations, and
vehicle exhaust from construction equipment, heavy trucks, and workers'
vehicles. People in passing vehicles, or residents or workers at nearby
properties may detect odors at intermittent points during construction
of the conveyance system. Impacts would occur intermittently during the
allowable construction hours between 7 a.m. and 10 p.m. (Spokane County
Code, Section 6.12.020, Exemptions) and for the period of construction
only. The conveyance system would be installed in segments, and would
last approximately a week in any given segment. Because impacts to air
quality during installation of the conveyance system are short-term and
temporary, they are not expected to be significant.
Odor-causing substances that commonly occur in wastewater consist of
both organic and inorganic compounds. The compounds usually arise from
biological activity in the wastewater collection and treatment system.
Most odor-causing compounds form as a result of anaerobic decomposition
of organic material containing sulfur and nitrogen.
Odor emissions are most likely to occur during periods of increased
ambient temperature and at points of turbulence within the collection
and treatment processes. The presence and direction of prevailing
breezes and the proximity of homes or offices to the proposed treatment
plant would influence the degree of impact, and impacts could vary as
weather patterns change throughout the year.
Operational impacts associated with Alternative 1 would be similar to
existing conditions. The number of staff is expected to be
approximately the same as described below for Alternatives 2 through 4
with approximately 18 vehicle trips per day. A measurable increase in
detectable odor emissions from the SAWTP under Alternative 1 is not
expected since odor control would be provided as part of the expansion
design. Long-term impacts to air quality would be similar for
Alternatives 2 through 4. Impacts would mainly include odors from
wastewater treatment, and would also include exhaust from equipment
motors and worker vehicles. Alternatives 2 and 3 would add one new
treatment plant to the Spokane Valley area, and Alternative 4 would add
two new treatment plants. An additional treatment plant or plants could
contribute odors to the Spokane Valley area. Detectable odors are not
expected to be significant due to odor control methods that will be
incorporated into plant design. Impacts to surrounding properties would
depend upon final site selection, but would likely be greatest in a
location near a residential area, and less in an industrial location.
Long-term impacts to air quality as a result of operation of the
conveyance system would generally be limited to emissions from workers'
vehicles during inspection or maintenance activities. There is
potential for some odor production from pump stations due to an increase
in turbulence at these locations. Long-term impacts are not expected to
be significant.
Treatment and conveyance of wastewater under Alternatives 1 through 4
could result in the release of volatile organic compounds (VOCs) or
aerosols. VOCs are compounds of carbon (excluding carbon monoxide,
carbon dioxide, carbonic acid, metallic cabides or carbonates, and
ammonium carbonate) which participate in atomospheric photochemical
reactions. Aerosols are very small airborne droplets that may be
generated at aerated process points in a wastewater treatment plant and
can be carried through the atmosphere. Adverse impacts associated with
VOCs and aerosols are not expected to be significant. Pump stations and
many treatment plant processes will be enclosed to prevent untreated
dispersion of VOCs and aerosols to the outside environment. The air
drawn off the facility will be treated via a chemical scrubber or carbon
treatment system prior to release.
Mitigation measures will be implemented to control dust and vehicle
emissions during construction and control odor emissions during
operation. Construction mitigation would include such measures as
wetting exposed surfaces, washing vehicles prior to leaving the project
site, and shutting off engines when not in use. Operation measures
would include proper sizing of transport systems, and areas exposed to
the atmosphere, servicing of odor control units, chlorination, and
keeping equipment and vehicles in good working order to reduce
emissions.
A variety of odor control measures may also be adopted to reduce or
eliminate odors from treatment plant operations. Typical odor-control
measures used at wastewater treatment plants include collection of
emissions followed by "scrubbing" to remove odors or other contaminants
such as VOCs and aerosols, prior to release to the environment. Process
controls that optimize the breakdown of wastes in the wastewater stream
can also reduce or eliminate serious odor problems. In addition, the
treatment facility would be sited to maximize the distance between the
plant and nearby properties where feasible. Some sites would allow a
design that maximizes the buffer between the plant and affected
properties, while other sites would be more constrained, limiting
opportunities for buffer area between the plant and surrounding
properties.
This section discusses the general transportation system in the City of
Spokane and Spokane County. Impacts to local street grids are discussed
as well as potential mitigation measures.
The project area falls within the City of Spokane and unincorporated
greater Spokane Valley and consists of business, residential, and
industrial areas. The street grid in the vicinity of the Spokane Area
Wastewater Treatment Plant (SAWTP) consists of both main arterials and
side streets. Interstate 90 (I-90) runs west to east and is
approximately 3.75 miles south of the SAWTP; US 2/395 runs north to
south and is approximately 3.25 miles east of the SAWTP.
The Spokane Valley lies to the east of the City of Spokane. I-90 runs
approximately east to west through the Spokane Valley (Refer to Figure
1). SR-290 also runs approximately east to west through the valley and
is paralleled by the Burlington-Northern Railroad line. U.S. Highway 2
joins I-90 just west of Spokane and follows I-90 for a few miles before
heading north. U.S. Highway 395 follows the I-90 route until its
junction with Highway 2. Approximately six miles north of the junction,
U.S. Highway 395 splits off to the northwest and Highway 2 heads north.
U.S. Highway 195, a major north-south highway through eastern
Washington, follows the Latah Creek Valley and connects with I-90. The
street grid within the Spokane Valley consists of both main arterials
and side streets within a mainly commercial and industrial mix of uses.
Numerous Spokane County Public Works projects are proposed (Spokane
County, 2001a), some of which may coincide with construction of the
Spokane Wastewater Treatment Facility project. Public works projects
include both road and utility construction or maintenance. Coordination
between Public Works and treatment facility construction projects would
be important to minimize or eliminate transportation impacts in the
project vicinity.
The Spokane Metropolitan Area, Metropolitan Transportation Plan
(1999) sets forth standards and guidelines for transportation planning
in the City of Spokane and surrounding areas. Policy Topic
5—Transportation of the Countywide Planning Policies for Spokane
County (1998) sets forth policies and guidelines for regional
transportation planning for Spokane County. These policies are guided
by the Growth Management Act (GMA), and encourage the coordination of
land use plans and policies through the Spokane Regional Transportation
Council (SRTC) to ensure they preserve and enhance the regional
transportation system (Spokane County, 1998).
Spokane County has established Level of Service (LOS) standards for the
county transportation system. LOS for regional transportation is based
on corridor travel time. Spokane County's Comprehensive Plan
(Spokane County, 2000a) has established LOS goals for transportation;
the following goals are applicable to the proposed wastewater treatment
plant project:
·
Goal T.8a Establish and maintain level of service standards for
roads.
·
Goal T.8d Clean streets as needed to meet air quality standards
for particulate matter (PM).
The City of Spokane has established a Level of Service
Standard/Concurrency Management System (LOS/CMS) as part of its
comprehensive planning efforts "to help manage growth and to assure that
adequate transportation facilities are in place concurrent with new
development" (City of Spokane, 2000; 2001a).
Construction-related impacts to transportation would be generally the
same for Alternatives 1 through 4. Impacts would include movement of
personal vehicles and heavy trucks into and out of the construction
site. Both personal vehicles and heavy trucks would use the local street
grid and would temporarily contribute to traffic volumes and possibly
congestion in the area. Construction activities are expected to last
approximately two years. During construction, approximately 50 heavy
truck trips per day would occur. Initially, truck trips would primarily
consist of removal of excavated soil from the site. As construction
progresses, heavy trucks and/or trailers would also enter and exit the
site to deliver or remove construction equipment and building
materials. Traffic would be periodically stopped along affected
roadways to allow heavy, large trucks and trailers to move into and out
of the site. This could result in temporary delays for general purpose
traffic. As construction nears completion, the number of heavy trucks
making deliveries would decrease, and the main traffic into and out of
the site would be personal vehicles of construction workers. Temporary
traffic detours could also occur during construction, increasing volumes
to other roadways and possibly increasing travel time for some
motorists. Due to the temporary nature of construction activities, no
significant adverse short-term impacts to transportation are expected to
occur.
Conveyance system construction would result in temporary disruptions to
traffic flow during excavation, installation of pipe and pump stations,
outfall construction, and roadway resurfacing activities. Temporary
traffic detours could also occur during construction, increasing volumes
to other roadways and possibly increasing travel time for some
motorists.
Alternatives 1 through 4 would require the construction of additional
conveyance facilities. Alternative 1 would require the largest
expansion of the conveyance system with construction of a new forcemain
through urban areas and two new pumping stations. The new forcemain
would be approximately 8 miles long. This could cause traffic
disruptions over a large area and construction impacts such as dust and
noise would impact businesses and residences. Alternative 3 would also
require construction of a new forcemain through an urban area. This
would have similar impacts to Alternative 1, but on a smaller scale
since the forcemain would be shorter. Alternatives 2 and 4 would also
require construction of forcemains and pump stations, but the required
conveyance facilities would be smaller and construction would occur in
areas where construction would be less disruptive of traffic and
businesses.
Operational impacts to transportation are expected to be minor because
in general a wastewater treatment plant generates relatively few trips
per acre. Treatment plant workers' vehicles would enter and exit the
site on a daily basis. A new treatment plant could be staffed 24-hours
per day, although automation may allow a plant to operate without
on-site staff at night and on weekends. Approximately five employees
per 8-hour shift would work at the treatment plant. Estimating
approximately two car/truck trips per day per employee would result in
approximately 18 trips per day. Additional staff would be added under
Alternative 1, resulting in an increase in the number of vehicle trips
to and from this site. Biosolids and other solid waste would be removed
from the site on a daily basis. Regular municipal solid waste would be
picked up once a week. Three to four heavy truck trips per day would be
generated for biosolids transport. The relative significance of the
addition of these vehicle trips to local roadways would be dependent
upon the final site selection and existing traffic and road conditions
in the area.
During final site selection, the transportation analysis will be able to
be more specific about traffic impacts for alternative plant sites.
No long-term transportation impacts associated with operation of the
conveyance system, pump stations, or outfall are expected.
Mitigation measures for construction-related impacts would include
signage alerting drivers to the presence of large construction vehicles,
and flaggers to control traffic flow at and/or near the entrance to the
construction site. Because operational impacts are not expected to be
significant, no long-term mitigation measures would be provided.
Spokane currently has a number of demand management practices in place
to reduce the quantity and/or strength of wastewater transported to the
treatment facilities. These measures include a ban on
phosphorous-containing detergents, an industrial pretreatment program,
effective control of infiltration and inflow, and a requirement that new
construction of major remodels use low volume plumbing.
The proposed measures for demand management are not expected to impact
any of the elements of the environment being considered in this EIS.
All of the measures are administrative and would not involve any
construction. Some of the measures could have economic impacts on
utility customers who might have to pay more for water or retrofit their
sump pump systems to eliminate discharges to sewers.
No mitigation measures are proposed because no impacts are anticipated.
Reclaimed water has been used in the State of Washington since
approximately 1997 when the State Legislature directed the Department of
Ecology and the Department of Health to establish and administer a
reclaimed water demonstration program (Ecology, 2000). Reclaimed water
uses include irrigation of food/non-food crops, landscaping/lawns,
landscape impoundments, restricted and nonrestricted recreational
impoundments, constructed treatment wetlands, groundwater recharge,
commercial and industrial uses, and streamflow augmentation. Washington
State has four classes of reclaimed water that are classified by the
level of treatment provided. Class A reclaimed water receives the
highest level of treatment while Class D receives the least amount of
treatment above standard wastewater treatment levels. All reclaimed
water suitable for reuse undergoes treatment and disinfection generally
over and above conventional wastewater treatment facilities.
Areas of concern have included the effects of reclaimed water on
groundwater quality, particularly where it is used specifically for
groundwater recharge, and health effects to humans who come into contact
with the reclaimed water.
Spokane County is considering seven alternatives for effluent end use
including streamflow augmentation; irrigation of a poplar farm, urban
greenspaces, or agricultural land; industrial reuse; wetlands creation
or enhancement; and groundwater recharge. Refer to Section 2.5.2 for a
description of effluent end use alternatives.
Relevant Local and State Standards
and Guidelines. The Washington State Department of Ecology
has developed a set of standards and guidelines for reclaimed water use
within Washington State. This document, Water Reclamation and Reuse
Standards (Washington Department of Health and Washington Department
of Ecology, 1997), covers all aspects of reclaimed water use including
allowable uses; methods of treatment; sampling and analysis;
operational, design, reliability, and use area requirements; standards
for wetlands; and standards for direct aquifer recharge.
Construction. Short-term
impacts associated with reclaimed water use would be limited to the
construction activities necessary to bring the water to a given site and
the installation of an appropriate delivery system (e.g., sprinkler
system). These activities could include excavation, and noises
associated with workers' vehicles and machinery.
It is anticipated that effluent intended for reuse would be transported
to application areas via a subsurface conveyance system. It is expected
that the selected conveyance system route would primarily utilize
existing roadways. Conveyance system construction would result in
temporary disruptions to traffic flow during excavation, installation of
pipe and pump stations, and roadway resurfacing activities. Temporary
traffic detours could also occur during construction, increasing volumes
to other roadways, and possibly increasing travel time for some
motorists. The extent of transportation impacts would depend upon the
distance to the chosen re-use areas and the traffic volumes along the
conveyance routes. Conveyance for irrigation and wetland
creation/enhancement would likely have a greater impact to
transportation than the conveyance required for industrial uses, due to
greater distances and the larger number of use areas.
Construction of the conveyance system would cause temporary increases in
erosion and sedimentation to nearby water bodies. The conveyance system
may require stream crossings. If the conveyance system is installed
along existing roadways, there would be no impact to plants, but
installation in unpaved areas would require clearing. Construction
noise and activities could temporarily displace animals. Construction
impacts to environmental health, energy, and air quality would be
similar to those described in Sections 3.3, 3.5, and 3.6.
Operation. As described
above under Relevant Local and State Standards and Guidelines, reclaimed
water would be treated in accordance with guidelines in the Water
Reclamation and Reuse Standards (Washington Department of Health and
Washington Department of Ecology, 1997). Reclaimed water intended for
poplar farm irrigation would be treated to Class C standards. Reclaimed
water intended for all other uses would be treated to Class A
standards. Reclaimed water used for industrial reuse may receive
additional treatment for color. Water used for wetlands will also be
treated for phosphorous and total nitrogen reduction and water used for
groundwater recharge will be treated to Class A standards followed by
reverse osmosis. Any reuse would comply with the standards for specific
use types as defined in Water Reclamation and Reuse Standards.
Operational impacts related to the use of reclaimed water are not
expected to be significant. Water resource impacts would be minimized
by following the state guidelines for reclaimed water (Washington
Department of Health and Washington Department of Ecology, 1997). No
adverse impacts are expected as a result of agricultural or urban
irrigation with Class A effluent. Class A effluent has received the
highest level of treatment and is considered safe for all irrigation
methods, including spray irrigation. Poplar farm irrigation using Class
B effluent is not expected to result in adverse impacts because no food
products would be produced and the farm would not be used by humans for
purposes such as recreation. In addition, irrigation rates would follow
irrigation requirements for crops in Spokane County as calculated by
David Bezdicek of Washington State University.
The water quality of any surface or groundwater body to which reclaimed
water is discharged is not expected to be adversely impacted. Reclaimed
water discharged directly to water bodies such as the Spokane River
would receive treatment in accordance with Ecology standards and
requirements prior to discharge. Refer to Section 3.2 Water Resources
for a detailed discussion of water quality issues in the Spokane area.
The use of treated effluent to recharge groundwater requires that the
effluent be treated to drinking water and groundwater standards. State
standards allow groundwater recharge through surface percolation and
direct injection. The Reuse Standards include provisions requiring
reclaimed water to be held underground a minimum of 12 months prior to
being withdrawn for drinking water and a minimum horizontal distance
separating the point of direct recharge and the point of withdrawal for
drinking water. These standards are intended to insure that aquifer
recharge will not adversely impact groundwater quality.
No adverse impacts are expected as a result of using reclaimed water for
wetland creation or enhancement. Reclaimed water would be treated to
Class A standards and created wetlands located in areas with potential
interaction with potable water aquifers would be lined. Beneficial
impacts related to the restoration or enhancement of degraded wetlands
could be anticipated as a result of using reclaimed water. Reclaimed
water would provide a reliable water supply in areas where natural flows
have decreased as a result of development.
Impacts related to the use of reclaimed water for industrial uses could
include a temperature increase in a facility's effluent, due to the fact
that treatment plant effluent could be as much as 15 degrees warmer than
groundwater. This could require a facility to implement measures to
cool the water to the facility's permitted temperature requirement prior
to discharge.
Effluent application on poplar farms as part of an effluent end-use
program would require approximately 3,600 acres by 2025, and
approximately 4,500 acres in 2050, which includes land needed for
buffers, harvesting requirements, and other property management
functions. The acreage required for the poplar farms could have impacts
on land use in the Spokane area. Impacts could include rezoning or
redesignating land uses for selected tracts. In addition, removing
developable land from the tax rolls could adversely affect Spokane
County's revenue stream. A potential beneficial land use impact
resulting from irrigation with reclaimed water could be an increase in
the value of agricultural land that currently does not have a reliable
water supply.
The effluent end use alternatives would all require a significant amount
of energy due to extensive pumping requirements associated with
transporting effluent. Refer to Section 3.5, Energy and Natural
Resources, for a description of energy and natural resource issues
associated with wastewater treatment.
Reclaimed water treated to Class B standards or better does not carry an
odor and has been treated and disinfected such that the number of total
coliform organisms does not exceed 23 per 100 milliliters in any
sample. No impacts to air quality are anticipated as a result of
effluent end use. Effluent intended for reuse would be treated to Class
A or Class B standards and does not carry an odor. Refer to section
3.6, Air Quality, for a description of air quality issues associated
with wastewater treatment.
No long-term impacts to transportation are anticipated as a result of
effluent (reclaimed water) end use activities.
Mitigation for impacts associated with use of reclaimed water would
include, the applicable measures in Ecology’s Water Reclamation and
Reuse Standards (Ecology, 1997). The appropriate standards for each
type of end use would be applied.
Best management practices and standard noise and dust reduction
techniques and erosion control measures would be used to minimize the
impacts of construction. No impacts to environmental health, plants and
animals, air quality or transportation are expected to occur as a result
of effluent end use activities, therefore, no mitigation is proposed.
Biosolids are the residual solids remaining after wastewater treatment.
Biosolids contain organic matter and plant nutrients. This treatment
by-product can make a good soil amendment and many communities,
including Spokane, have successfully applied biosolids to farmland for
decades. Biosolids proposed for reuse in the Spokane Valley area would
be treated to Class B standards or better.
Relevant Local and State Standards
and Guidelines. Biosolids are regulated under Chapter 173-308 Biosolids
Management of the Washington Administrative Code (WAC). Chapter 173-308
WAC provides a definition of biosolids as used by Washington State and
sets forth standards and guidelines for the treatment and use of this
material.
The U.S. Environmental Protection Agency (EPA) established standards for
biosolids disposal and use under 40 CFR 503 (the Part 503 rule) in
1993. These guidelines are intended to protect public health and the
environment from the adverse effects of certain pollutants that might be
present in biosolids. Three measures are used to determine if biosolids
are of sufficient quality for use in various applications: 1)
concentration of trace elements, 2) quantity of pathogens, and 3) vector
(e.g., flies, rodents) attraction.
The alternatives for biosolids management include land application,
composting, treatment at the City of Spokane facility, incineration, and
privatized management. Refer to Section 2.5.3 for a description of
biosolids management alternatives.
Construction. The
composting alternative would experience construction-related impacts
such as noise from construction equipment and vehicles, fugitive dust
from excavation activities, and emissions from equipment and vehicle
engines. Construction-related impacts associated with the land
application alternative would be minimal and would likely be limited to
site preparation and possibly construction of access roads. The
co-incineration alternative would have no construction-related impacts
because this alternative uses an existing regional incineration
facility. The treatment at City of Spokane Facility would require
construction of a pump station and forcemain to transport sludge to the
SAWTP. This would involve significant construction impacts over a wide
area. Privatized management alternatives would have no
construction-related impacts as the biosolids would be processed at an
existing processing site.
Operation.
Because of the strict guidelines associated with the treatment
and use of biosolids, no significant adverse impacts are expected as a
result of use of this material.
Composting of biosolids to produce Class A biosolids would require large
areas of land and could pose siting problems. Biosolids Alternative 3
would require approximately 20 acres of land. This requirement could
transfer this land from private ownership to public ownership and would
remove it from the tax rolls. Composting can generate significant odors
which would impact site selection.
Biosolids would be treated to the strict guidelines that regulate
biosolids treatment and use. Therefore, no significant adverse impacts
to water resources are expected. Biosolids are required to be applied
at agronomic rates to balance the uptake of nitrogen by crops with the
potential for nitrate leaching to groundwater. Adherence to these
application rates and to requirements to buffer biosolids application
areas from surface waters will minimize the impacts to receiving water
bodies. Required monitoring of soil and water concentrations will
further protect water resources.
Environmental health concerns associated with biosolids could include
exposure to microorganisms; metal concentrations in soil, water, and
plants; and organic compounds. Studies examining the potential health
effects of pathogens in biosolids have shown no adverse health effects
of land application of biosolids even in highly exposed individuals or
in populations near biosolids recycling areas. Large concentrations of
trace metals such as copper, nickel, arsenic, mercury, lead, and cadmium
have shown toxic effects on plants, animals, and humans. The 503
regulations have strict "ceiling concentrations" on the amounts of these
metals that are allowed in biosolids. Biosolids that do not meet these
requirements cannot be applied to land.
Biosolids would be sufficiently treated so that they do not produce
significant amounts of odor. Odors produced during treatment would be
collected and treated prior to release to the atmosphere as described
under Air Quality in section 3.6. Some exhaust would be produced by
heavy trucks used to transport biosolids from the plant to disposal
areas. Class B biosolids applied to agricultural lands may emit a musty
organic or ammonia like odor when freshly applied. The odor diminishes
rapidly as the biosolids dry out. Odor associated with biosolids
application is very localized and dissipates quickly with distance.
Application of biosolids generally enhances the growth and vigor of
plants. Research has demonstrated that plants grown in biosolids
amended soils pose no greater health risk than those without. Animals
can be adversely impacted by direct contact with biosolids or by
alterations in vegetation. Wildlife can be impacted by bioaccumulation
of metals and trace organics; accumulation varies by species. However,
the application of biosolids does not appear to significantly affect
wildlife populations. In general, metal accumulation is low and not
harmful to individuals or populations. Under 503 regulations, biosolids
cannot be applied on any site where they are likely to adversely affect
endangered species.
Some energy may be saved as the result of land application of biosolids
since the demand for chemical fertilizers will be reduced. Production
of chemical fertilizers requires large amounts of energy. Energy will
be expended in the transport of biosolids to the application or
processing sites. Offsite transport of biosolids by private contractors
would require longer truck trips and consume more energy.
Impacts to transportation that result from biosolids management would
generally be limited to heavy trucks entering and exiting the treatment
plant site to transport biosolids to application or disposal sites.
Under Alternative 1, biosolids production is expected to increase;
approximately three to four truck trips per day are anticipated for
biosolids removal at an expanded SAWTP. Alternatives 2 and 4 would add
approximately three to four heavy truck trips per day to local streets
for biosolids transport. No significant adverse impacts to
transportation are expected as a result of biosolids transport under
Alternatives 1 through 4. No additional truck traffic would be added to
local streets as a result of Alternative 5; therefore, no impacts would
occur. Privatized management of the biosolids would generate longer
truck trips with the biosolids.
Alternative 3, composting, would require trucking sludge to a composting
site and then trucking the composted material to the point of
distribution or use. This would result in slightly increased truck
traffic over Alternatives 2 and 4.
Application or disposal of biosolids would comply with all local, state
and federal regulations. No biosolids application would occur on
unauthorized properties. All appropriate safeguards to protect human
health and the environment would be followed. These mitigation measures
are expected to minimize the impacts associated with biosolids
application. In addition, the following mitigation measures could be
implemented.
Biosolids will be monitored for concentrations of pathogens, trace
metals, and organics compounds to ensure that the biosolids do not
contain toxic levels of these materials. In addition, soils will be
monitored to gauge accumulations of trace metals and ground and surface
water bodies will be monitored.
Trucks transporting biosolids to use or disposal areas would follow all
state and local regulations regarding transport of these materials.
Covering of truck beds and cleaning of excess materials from the outside
of the truck bed prior to exit from the treatment plant site would
insure that biosolids materials do not blow out of the truck and onto
people, vehicles, or other property not intended for biosolids
application. Trucks used to transport biosolids would be maintained to
minimize pollutants in exhaust fumes. It is expected that loads would
be covered to prevent materials from escaping the truck bed and
introducing dust and debris into the air.
The relative significance of the addition of the three to four daily
heavy truck trips to local roadways would be dependent upon the final
site selection and existing traffic and road conditions in the area.
Mitigation measures could include traffic control devices such as
traffic control improvements to local roadways (e.g., stop signs, turn
lanes).
