State Ecology issues "suggested" stormwater regulations: Urge your elected representatives to read the document carefully before passing it
Olympia, WA - 4/11/02 - The State Department of Ecology (DOE) has issued five volumes –consisting of 1,033 pages of rules and regulations dealing with “stormwater management" for Western Washington. They are currently working on one for Eastern Washington. The manual in its entirety can be downloaded at http://www.ecy.wa.gov/programs/wq/stormwater/manual.html
and counties have been furnished these "suggested"
regulations, with the option of passing them as written or developing
their own, comparable regulations. Faced with such a daunting
task, cities like Sequim, Washington, have simply passed the
regulations as written, often without even reading through them.
As is typical with many of the rules and regulations these days, the need for such are built upon "models". Models have been proven as an unreliable, and unscientific, method of reaching conclusions, in that they can be tweaked according to the predetermined outcomes desired.
Citizens should take the time to notify their elected representatives of their concerns about the document, and urge them to read it in its entirety before arbitrarily passing it into law for their city or county.
regional organizations of Realtors recently employed
a researcher to review the volumes, and present some of the
new development that shall be required to comply with Minimum
#2. In addition, new development that exceeds certain
Creates or adds 2,000 square feet, or greater, of new,
replaced, or new plus replaced impervious surface area, or
Has land disturbing activity of 7,000 square feet or greater,
Creates or adds 5,000 square feet, or more, of new impervious
surface area, or
Converts 3/4 acres, or more, of native vegetation to lawn or
landscaped areas, or
Converts 2.5 acres, or more, of native vegetation to pasture.
planning is encouraged and may be used to tailor certain of the
Minimum Requirements to a specific basin (Minimum Requirement #9).
Treatment and flow control requirements may be achieved through
construction of regional facilities. Such facilities must be
operational prior to and must have capacity for new development.
The new, replaced, or total of new
plus replaced impervious surfaces is 2,000 square feet or more, or
7,000 square feet or more of land disturbing activities.
following redevelopment shall comply with Minimum Requirements #1
through 10 for the new impervious surfaces and converted pervious
Converts 2.5 acres, or more, of native vegetation to pasture.
the runoff from the new impervious surfaces and converted pervious
surfaces is not separated from runoff from other surfaces on the
project site, the stormwater treatment facilities must be sized for
the entire flow that is directed to them.
local government may allow the Minimum Requirements to be met for an
equivalent (flow and pollution characteristics) area within the same
site. For public roads’ projects, the equivalent area does not have
to be within the project limits, but must drain to the same receiving
projects have the same requirements as new development projects in
order to minimize the impacts from new surfaces. To not discourage
redevelopment projects, replaced surfaces aren’t required to be
brought up to new stonnwater standards unless the noted cost or space
runoff from new impervious surfaces, converted pervious surfaces, and
replaced impervious surfaces (if the applicable cost or space
threshold has been exceeded) is not separated from runoff from other
existing surfaces within the project site or the site, the guidance in
Volume III for offsite inflow shall be used to size the detention
governments can select from various bases for identifying projects
that must retrofit the replaced impervious surfaces on the project
site. Those can include:
Exceeding 50% of the assessed value of the existing improvements;
Exceeding 50% of the replacement value of the existing site improvements as
determined by the Marshall Value System, or a
Exceeding a certain dollar value of improvements; and
Exceeding a certain ratio of the new impervious surfaces to the
total of replaced plus new impervious surfaces.
local government’s thresholds for the application of stormwater
controls to replaced impervious surfaces must be at least as stringent
as Ecology’s thresholds. Local governments should be prepared to
demonstrate that by comparing the number and types of historical
projects that would have been regulated using the Ecology thresholds
versus the local government’s thresholds.
governments are allowed to institute a stop-loss provision on the
application of stormwater requirements to replaced impervious
surfaces. A stop-loss provision is an upper limit on the extent to
which a requirement is applied. For instance, there could be a maximum
percentage of the estimated total project costs that are dedicated to
meeting stormwater requirements. A project would not have to incur
additional stormwater costs above that maximum though the standard
redevelopment requirements will not be fully achieved. The allowance
for a stop-loss
governments can also establish criteria for allowing redevelopment
projects to pay a fee in lieu of constructing water quality or flow
control facilities on a redeveloped site. At a minimum, the fee should
be the equivalent of an engineering estimate of the cost of meeting
all applicable stormwater requirements for the project. The local
government should use such funds for the implementation of stormwater
control projects that would have similar benefits to the same
receiving water as if the project had constructed its required
improvements. Expenditure of such funds is subject to other state
cautions local governments about the potential long-term consequences
of allowing a fee-in-lieu of stormwater facilities. Sites that are
allowed to pay a fee continue without stormwater controls. If it is
determined, through future basin planning for instance, that controls
on such sites are necessary to achieve water quality goals or legal
requirements, the public may bear the costs for providing those
utility projects that replace the ground surface with in-kind material
or materials with similar runoff characteristics should not be subject
to redevelopment requirements except construction site erosion
governments are also encouraged to review all road projects for
changes in elevations or drainage flowpath that could cause flooding,
upland or stream erosion, or changes to discharges to wetlands. For
example, adding curbs will result in redirecting flows and possibly
causing new downstream impacts. The local government should set
project-specific requirements to avoid or mitigate those impacts.
2.5 Minimum Requirements
section describes the minimum requirements for stormwater management
at development and redevelopment sites. Section 2.4 should be
consulted to determine which requirements apply to any given project.
Volumes II through V of this manual present Best Management Practices
(BMP5) for use in meeting the Minimum Requirements.
this Chapter, guidance to meet the requirements of the Puget Sound
Water Quality Management Plan is written in bold and supplemental
guidelines that serve as advice and other materials are not in bold.
Minimum Requirement #1: Preparation of Stormwater Site Plans
projects meeting the thresholds in Section 2.4 shall prepare a
2,000 square feet threshold for impervious surfaces and 7,000 square
foot threshold for land disturbance are chosen to capture most single
family home construction and their equivalent. Note that the scope of
the stormwater site plan only covers compliance with Minimum
Requirements #2 through #5 if
the thresholds of 5,000 square feet of impervious surface or
conversion of ¾ acre of native vegetation to lawn or landscape, or
conversion of 2.5 acres of native vegetation to pasture are not
proposed by departments and agencies within the local government with
jurisdiction must comply with this requirement. The local government
shall determine the process for ensuring proper project review,
inspection, and compliance by its own departments and agencies.
Minimum Requirement #2: Construction Stormwater Pollution
new development and redevelopment shall comply with
in which the new, replaced, or new plus replaced impervious surfaces
total 2,000 square feet or more, or disturb 7,000 square feet or more
of land must prepare a Construction SWPP Plan (SWPPP) as part of the
Stormwater Site Plan (see 2.5.1). Each of the twelve elements must be
considered and included in the Construction SWPPP unless site
conditions render the element unnecessary and the exemption from that
element is clearly justified in the narrative of the
that add or replace less than 2,000 square feet of impervious surface
or disturb less than 7,000 square feet of land are not required to
prepare a Construction SWPPP, but must consider all of the twelve
Elements of Construction Stormwater Pollution Prevention and develop
controls for all elements that pertain to the project site.
Prior to beginning land disturbing activities, including
clearing and grading, all clearing limits, sensitive areas and their
buffers, and trees that are to be preserved within the construction
area should be clearly marked, both in the field and on the plans, to
prevent damage and offsite impacts.
Plastic, metal, or stake wire fence may be used to mark the
Construction vehicle access and exit shall be limited to one
route if possible.
Access points shall be stabilized with quarry spall or crushed
rock to minimize the tracking of sediment onto public roads.
Wheel wash or tire baths should be located on-site, if
Public roads shall be cleaned thoroughly at the end of each
day. Sediment shall be removed from roads by shoveling or pickup
sweeping and shall be transported to a controlled sediment disposal
area. Street washing will be allowed only after sediment is removed in
Street wash wastewater shall be controlled by pumping back
on-site, or otherwise be prevented from discharging into systems
Properties and waterways downstream from development sites
shall be protected from erosion due to increases in the volume,
velocity, and peak flow rate of stormwater runoff from the project
site, as required by local plan approval authority.
Downstream analysis is necessary if changes in flows could
impair or alter conveyance systems, streambanks, bed sediment or
Where necessary to comply with Minimum Requirement #7,
Stormwater retention/detention facilities shall be constructed as one
of the first steps in grading. Detention facilities shall be
functional prior to construction of site improvements (e.g. impervious
The local permitting agency may require pond designs that
provide additional or different stormwater flow control if
If permanent infiltration ponds are used for flow control
during construction, these facilities should be protected from
siltation during the construction phase.
The duff layer, native topsoil, and natural vegetation shall be
retained in an undisturbed state to the maximum extent
Prior to leaving a construction site, or prior to discharge to
an infiltration facility, stormwater runoff from disturbed areas shall
pass through a sediment pond or other appropriate sediment removal
BMP. Runoff from fully stabilized areas may be discharged without a
sediment removal BMP, but must meet the flow control performance
standard of Element #3, bullet #1. Full stabilization means concrete
or asphalt paving; quarry spalls used as ditch lining; or the use of
rolled erosion products, a bonded fiber matrix product, or vegetative
cover in a manner that will fully prevent soil erosion. The Local
Permitting Authority shall inspect and approve areas stabilized by
means other than pavement or quarry spalls.
Sediment ponds, vegetated buffer strips, sediment barriers or
filters, dikes, and other BMPs intended to trap sediment on-site shall
be constructed as one of the first steps in grading. These BMPs shall
be functional before other land disturbing activities take place.
Earthen structures such as dams, dikes, and diversions shall be
seeded and mulched according to the timing indicated in Element
All exposed and unworked soils shall be stabilized by
application of effective BMPs, that protect the soil from the erosive
forces of raindrop impact and flowing water, and wind erosion.
From October 1 through April 30, no soils shall remain exposed
and unworked for more than 2 days. From May 1 to September 30, no
soils shall remain exposed and unworked for more than 7 days. This
condition applies to all soils on site, whether at final grade or not.
These time limits may be adjusted by the local permitting authority if
it can be shown that the average time between storm events justifies a
Applicable practices include, but are not limited to, temporary
and permanent seeding, sodding, mulching, plastic covering, soil
application of polyacrylamide (PAM), early application of gravel base
on areas to be paved, and dust control.
Soil stabilization measures selected should be appropriate for
the time of year, site conditions, estimated duration of use, and
potential water quality impacts that stabilization agents may have on
downstream waters or ground water.
Soil stockpiles must be stabilized and protected with sediment
Work on linear construction sites and activities, including
right-of-way and easement clearing, roadway development, pipelines,
and trenching for utilities, shall not exceed the capability of the
individual contractor for his portion of the project to install the
bedding materials, roadbeds, structures, pipelines, and/or utilities,
and to re-stabilize the disturbed soils, meeting the timing conditions
Cut and fill slopes shall be designed and constructed in a
manner that will minimize erosion.
Consider soil type and its potential for erosion.
Reduce slope runoff velocities by reducing the continuous
length of slope with terracing and diversions, reduce slope steepness,
and roughen slope surface.
Divert upslope drainage and run-on waters from off-site with
interceptors at top of slope. Off-site stormwater should be handled
separately from stormwater generated on the site. Diversion of
off-site stormwater around the site may be a viable option. Diverted
flows shall be redirected to the natural drainage location at or
before the property boundary.
Contain downslope collected flows in pipes, slope drains, or
Provide drainage to remove ground water intersecting the slope
surface of exposed soil areas.
Excavated material shall be placed on the uphill side of
trenches, consistent with safety and space considerations.
Check dams shall be placed at regular intervals within trenches
that are cut down a slope.
Stabilize soils on slopes, as specified in Element #5.
All storm drain inlets made operable during construction shall
be protected so that stormwater runoff shall not enter the conveyance
system without first being filtered or treated to remove sediment.
All approach roads shall be kept clean, and all sediment and
street wash water shall not be allowed to enter storm drains without
prior and adequate treatment unless treatment is provided before the
storm drain discharges to waters of the State.
Channels and Outlets
All temporary on-site conveyance channels shall be designed,
constructed and stabilized to prevent erosion from the expected
velocity of flow from a 2 year, 24-hour frequency storm for the
Stabilization, including armoring material, adequate to prevent
erosion of outlets, adjacent streambanks, slopes and downstream
reaches shall be provided at the outlets of all conveyance systems.
All pollutants, including waste materials and demolition
debris, that occur on-site during construction shall be handled and
disposed of in a manner that does not cause contamination of
Cover, containment, and protection from vandalism shall be
provided for all chemicals, liquid products, petroleum products, and
non-inert wastes present on the site (see Chapter 173-304 WAC for the
definition of inert waste).
Maintenance and repair of heavy equipment and vehicles
involving oil changes, hydraulic system drain down, solvent and
de-greasing cleaning operations, fuel tank drain down and removal, and
other activities which may result in discharge or spillage of
pollutants to the ground or into stormwater runoff must be conducted
using spill prevention measures, such as drip pans. Contaminated
surfaces shall be cleaned immediately following any discharge or spill
incident. Emergency repairs may be performed on-site using temporary
plastic placed beneath and, if raining, over the vehicle.
Wheel wash, or tire bath wastewater, shall be discharged to a
separate on-site treatment system or to the sanitary sewer.
Application of agricultural chemicals, including fertilizers
and pesticides, shall be conducted in a manner and at application
rates that will not result in loss of chemical to stormwater runoff.
Manufacturers’ recommendations shall be followed for application
rates and procedures.
Management of pH-modifying sources shall prevent contamination
of runoff and stormwater collected on the site. These sources include,
but are not limited to, bulk cement, cement kiln dust, fly ash, new
concrete washing and curing waters, waste streams generated from
concrete grinding and sawing, exposed aggregate processes, and
concrete pumping and mixer washout waters.
All foundation, vault, and trench de-watering water, which has
similar characteristics to stormwater runoff at the site, shall be
discharged into a controlled conveyance system, prior to discharge to
a sediment trap or sediment pond. Channels must be stabilized, as
specified in Element #8.
Clean, non-turbid de-watering water, such as well-point ground
water, can be discharged to systems tributary to state surface waters,
as specified in Element #8, provided the de-watering flow does not
cause erosion or flooding of the receiving waters. These clean waters
should not be routed through sediment ponds with stormwater.
Highly turbid or otherwise contaminated dewatering water, such
as from construction equipment operation, clamshell digging, concrete
tremie pour, or work inside a cofferdam, shall be handled separately
from stormwater at the site.
Other disposal options, depending on site constraints, may
include: 1) infiltration, 2) transport off-site in vehicle, such as a
vacuum flush truck, for legal disposal in a manner that does not
pollute state waters, 3) on-site treatment using chemical treatment or
other suitable treatment technologies, or 4) sanitary sewer discharge
with local sewer district approval if there is no other option.
All temporary and permanent erosion and sediment control BMPs
shall be maintained and repaired as needed to assure continued
performance of their intended function. All maintenance and repair
shall be conducted in accordance with BMPs.
Sediment control BMPs shall be inspected weekly or after a
runoff-producing storm event during the dry season and daily during
the wet season.
All temporary erosion and sediment control BMPs shall be
removed within 30 days after final site stabilization is achieved or
Phasing of Construction - Development projects shall be phased
where feasible in order to prevent, to the maximum extent practicable,
the transport of sediment from the development site during
construction. Revegetation of exposed areas and maintenance of that
vegetation shall be an integral part of the clearing activities for
and grading activities for developments shall be permitted only if
conducted pursuant to an approved site development plan (e.g.,
subdivision approval) that establishes permitted areas of clearing,
grading, cutting, and filling. When establishing these permitted
clearing and grading areas, consideration should be given to
minimizing removal of existing trees and minimizing
disturbance/compaction of native soils except as needed for building
purposes. These permitted clearing and grading areas and any other
areas required to preserve critical or sensitive areas, buffers,
native growth protection easements, or tree retention areas as may be
required by local jurisdictions, shall be delineated on the site plans
and the development site.
Seasonal Work Limitations - From October 1 through April 30,
clearing, grading, and other soil disturbing activities shall only be
permitted if shown to the satisfaction of the local permitting
authority that silt-laden runoff will be prevented from leaving the
construction site through a combination of the following:
Site conditions including existing vegetative coverage, slope,
soil type and proximity to receiving waters; and
Limitations on activities and the extent of disturbed areas;
Proposed erosion and sediment control measures.
on the information provided, and/or local weather conditions, the
local permitting authority may expand or restrict the seasonal
limitation on site disturbance. If, during the course of any
construction activity or soil disturbance during the seasonal
limitation period, silt-laden runoff leaving the construction site
causes a violation of the surface water quality standard or if
clearing and grading limits or erosion and sediment control measures
shown in the approved plan are not maintained, the local permitting
authority shall take enforcement action,
including, but not limited to a notice of violation, administrative
order, penalty, or stop-work order.
following activities are exempt from the seasonal clearing and grading
Routine maintenance and necessary repair of erosion and sediment
Routine maintenance of public facilities or existing utility
structures that do not expose the soil or result in the removal of the
vegetative cover to soil; and
Activities where there is one hundred percent infiltration of
surface water runoff within the site in approved and installed erosion
and sediment control facilities.
Coordination with Utilities and Other Contractors - The primary
project proponent shall evaluate, with input from utilities and other
contractors, the stormwater management requirements for the entire
project, including the utilities, when preparing the Construction SWPPP.
Inspection and Monitoring - All BMPs shall be inspected,
maintained, and repaired as needed to assure continued
Certified Professional in Erosion and Sediment Control shall be
identified in the Construction SWPPP and shall be on-site or on-call at
all times. Certification may be through the Washington State Department
of Transportation/Associated General Contractors (WSDOT/AGC)
Construction Site Erosion and Sediment Control Certification Program or
any equivalent local or national certification and/or training program.
and analysis of the stormwater discharges from a construction site may
be necessary on a case-by-case basis to ensure compliance with
standards. Monitoring and reporting requirements may be established by
the local permitting authority when necessary.
inspection and/or monitoring reveals that the BMPs identified in the
Construction SWPPP are inadequate, due to the actual discharge of or
potential to discharge a significant amount of any pollutant, the SWPPP
shall be modified, as appropriate, in a timely manner.
Maintenance of the Construction SWPPP - The Construction SWPPP
shall be retained on-site or within reasonable access to the site. The
Construction SWPPP shall be modified whenever there is a significant
change in the design, construction, operation, or maintenance of any
above items are from Volume 1 - Minimum Technical Requirements, August
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