Plan urges city to OK sewers
October 2, 2008 · Updated 2:40 PM
CARNATION A new plan to build sewers and a wastewater
treatment facility in Carnation promises to keep rivers clear while allowing
for more residential and business growth.
But it's going to take time and money.
The proposal, conducted by American Engineering Corp.
of Redmond, was authorized by the city council and the local Sewer
Advisory Committee. It calls for the city to spend more than $3 million on
initial construction of a wastewater treatment facility and another $3.2 million on
the first phase of a city sewer system.
According to the proposal, the rest of the city would be phased in over
a 20-year period. The estimated total cost of those three phases is more
than $5.7 million.
In its executive summary to the proposal, the engineering firm says
the city of Carnation, which had a population of 1,725 in 1998-1999 and
grew at an annual rate of 3.8 percent from 1993 to 1999, can't continue to
develop by solely using septic systems for homes and businesses. It
further projects Carnation's population to reach 4,965 by 2020.
"The growth pressure in the area is beyond the control of the city,"
the summary states. "Other future needs such as home remodeling,
new-home construction, business expansion and buying and selling of homes
cannot occur unless adequate wastewater treatment is provided."
At the same time, the downtown area is losing tenants. Businesses
are unable to expand or rebuild because septic systems can't deal with it,
causing them to close shop.
"The need (for a sewer system) is critical," said Mayor Bob
Patterson. "Our downtown is dying, and I
don't think it could be brought back to life without a sewer."
The plan calls for grinder pumps to deliver waste to
small-diameter, low-pressure mains, which would
then transport the waste to the treatment plant. The lines and mains of the
sewer system would only be 30 to 36 inches deep _ shallow enough to limit
the amount of digging needed to install them.
"It's much easier to put in _ no big ditches, no gravity sewer,"
Einar Gundersen, president of American Engineering, said the
firm was conscious of two important conditions when drawing up the
"They (city officials) want to make sure the facilities that are proposed
are cost-effective. And the city also wanted to make sure that the
facilities proposed actually improve water quality," he said.
Patterson said the city wanted to keep the price, "as low as
possible, but we need to have a complete facility." Information contained within
the proposal states residents of Carnation typically earn less than other
residents of King County.
The wastewater treatment plant would be located on a 10-acre
lot along West Entwistle Street. Sewage would go through a sludge
treatment process, and the remaining water would be disinfected and
discharged into the Snoqualmie River.
The river is home to anadromous _ including Chinook _ fish and
other species. But planners say the impact to the watershed would be minimal.
"Pollutant loading to the river will not be significant due to the
small quantity of sewage discharged and the enhanced removal capabilities of
the continuous flow-activated sludge treatment plant," the proposal
states. In turn, the plant would also prevent contaminating the city's groundwater.
" A gradual phase-out of (septic) systems over the next 20
years will, likewise, alleviate groundwater contamination issues associated
with septic systems."
Currently there are 700 septic systems in Carnation, and most of
them were built five to 20 years ago. The typical lifespan of a septic system
is 20 years, says American Engineering.
In its proposal, American Engineering suggests the first phase of
construction would include building the wastewater treatment facility
and sewers for "the Central Business District and the area generally
located west of the King County Parks Trail."
Patterson said implementing the wastewater treatment system in
phases would help offset the financial impact of the problem. "We wanted to go
as small as we could the first time because of money."
Phase 2 consists of building sewers to homes on the east side of
the city. Phase 3 includes two urban growth areas, one in north
Carnation, the other on the southwest corner of the city. And Phase 4 would
link homes and businesses in the eastern edge and southeast parts of the city
to the sewer system.
To pay for the system, the Carnation mayor said the city would go
after grants and low-interest loans, a process he's already started. But
those connected to the sewer system will have to share some of the cost.
The costs for using the sewer system are broken down three ways.
Initially, those connected with the system would pay an assessment
based upon the square footage of the home or business. The assessment
includes two fees, one for the sewer system and another for the wastewater
For example, an 8,000-square-foot home would pay an assessment
of $2,800 $1,700 for collection and $1,100 for treatment. A
10,000-square-foot home would receive an assessment of $3,075 $1,700
for collection and $1,375 for treatment.
Carnation businesses and homes hooked up to the system would
then pay $51 per month for each equivalent residential unit (ERU) they
use, which, says American Engineering, " will cover the cost of
operations, maintenance, debt service, depreciation (replacement), taxes and
administration." Those who use more than one ERU a month would pay
more. Water meters would be used to collect readings.
In addition, commercial uses that discharge high-strength waste
would be charged $63.75 per ERU.
Finally, a connection charge of about $4,000 per ERU will be
levied on those who didn't pay the assessment and want to connect to the
system. The connection charge is primarily for vacant homes or other
properties and land developers who want to connect to the sewer system.
Gundersen said the reason for the higher charge is "they need to
be brought up to the same level, and then they need to pay for future expansion."
In the future, the wastewater treatment plant could be updated to
produce reusable water that could be used to irrigate fields or in car
washes. Gundersen said the upgrade could be part of Phase 1, but it would cost
an additional $400,000 to $500,000.
Once the system is in place, Carnation would have the
infrastructure to attract businesses and
multi-unit, senior and low-income housing and allow the city to grow, but at the
pace it wants, Patterson said.
"We want to keep the rural area out here in the Valley," he said.