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The Stormwater Manual supporting the proposed ordinance below is available by download (15mb). |
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Dunes City Draft Chapter 99 Stormwater Pollution Reduction a/o 2/22/09 |
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Printable document (rtf) |
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(Before
the City Council, March 12, 2009) Sections: 99.10
Need 99.15
Purpose 99.20
Applicability 99.25
Financial Liability 99.30
Exemptions 99.35
Illicit Discharges 99.40
Abrogation and Greater Restrictions 99.45
Stormwater Best Management Practices (BMPs. 99.50
Stormwater Containment and Destination Standards 99.55
Pollution Reduction Standards 99.60
Flow Control Standards 99.65
Stormwater Source Controls 99.70
Stormwater Operations and Maintenance Standards 99.75
Inspection 99.80
Enforcement 99.85
Stop Work Order 99.90
Civil Penalty 99.95
Penalties Due 99.100 Exceptions 99.105 Finding
of Fact Exceptions 99.110 Prior
Approval 99.115 Duration
of Exceptionl 99.120 Right
of Appeal 99.125 Adjustment
Review-Approval Criteria 99.130 Stormwater
Management Manual 99.135 Definitions
99.05
Findings of Fact. The City Council of the City of Dunes City hereby finds that: A. Stormwater
pollution is a problem associated with land utilization and development
and results in the common occurrence of potential pollutants such as
pesticides, fertilizers, petroleum products, pet wastes, and numerous
others. B. Land
utilization and development is also known to increase both the volume and
duration of peak flows. The resulting erosion, scouring, and deposition of
sediment affect the ecological balance in all water bodies.
C. Sedimentation
and stormwater pollution cause diversity of species to decrease and allows
more tolerant (and usually less desirable) species to remain. D. Stormwater
pollution can cause or contribute to restrictions on public use of the
waters within the city E. An
expanding population and increased development of land have led to: 1.
Water quality degradation through discharge of nutrients, metals, oil and grease,
toxic materials, and other detrimental substances including, without
limitation, insect and weed control compounds. 2. Drainage and storm- and
surface-water runoff problems within the city. 3. Safety hazards to both lives and
property posed by uncontrolled water runoff on streets and highways. F. Continuation of present stormwater
management practices, to the extent that they exist, will lead to water
quality degradation, erosion, property damage, and will endanger the
health and safety of the inhabitants of G.
In the future such problems and dangers will be reduced or avoided
if existing properties and future developers, both private and public,
provide for stormwater quality and quantity controls. H. Stormwater
quality and quantity controls can be achieved when land is developed or
redeveloped by implementing appropriate best management practices (BMPs). I. Best management practices (BMPs) can be expected to perform as intended only when properly designed, constructed and maintained. 99.10
Need. The city council finds that this chapter is necessary in order to: A.
Fulfill Dunes City’s obligation to promote the public health,
safety and general welfare of its citizens, as delegated to it by the
Legislature of this State in ORS 221.410 and as defined in ORS 468.015
Policy. B.
Fulfill Dunes City’s obligation to enact Zoning Ordinances and
Regulations pertaining to the development of land as delegated to it by
the Legislature of this State in ORS 227.010 seq. C.
Fulfill Dunes City’s obligation to comply with Oregon’s
Statewide Planning Goals and Guidelines as outlined in Goal 6: Air, Water
and Land Resources Quality. D.
Implement Policies as outlined in the Dunes City Comprehensive Plan
adopted by Dunes City in September, 1997: 1. Policy B-9 (page 7). 2. Policy E-7 (page 11)
and, 3. Chapter IV, Section
B-2(a) (vi) (page 49). E.
Minimize or eliminate water quality degradation. F.
Prevent erosion and sedimentation in all water bodies. G.
Protect property owners adjacent to existing and developing lands
from increased runoff rates which could cause erosion of abutting
property. H. Preserve
and enhance the suitability of waters for contact recreation, fishing, and
other beneficial uses. I. Preserve
and enhance the aesthetic quality of the water. J.
Promote sound development policies which respect and preserve city
surface water, ground water and sediment. K. Ensure
the safety of city roads and rights-of-way. L. Decrease stormwater-related damage to public and private property from existing and future runoff. 99.15
Purpose. The purpose of this chapter is to: A. Establish
requirements and standards for protecting and safeguarding the general
health and safety of the public by reducing stormwater-related impacts on
the quality of the city’s water resources including drinking water. B. To provide
for standards for the capture and treatment of stormwater run-off from
impervious surface areas and to reduce the introduction of pollutants into
stormwater. C. Minimize water quality
degradation and sedimentation in streams, ponds, lakes, wetlands and other
water bodies. D. Minimize the impact of increased runoff, erosion and sedimentation
caused by land development and maintenance practices. E. Maintain and protect surfacewater and groundwater resources. F. Minimize adverse impacts of alterations on ground and surface water
quantities, locations and flow patterns. G. Decrease potential landslide, flood and erosion damage to public
and private property. H. Promote site planning and construction practices that are
consistent with natural topographical, vegetational and hydrological
conditions. I. Maintain and protect any city stormwater management facility. J. Provide a means of
regulating clearing, grading and development of private and public land
while minimizing water quality impacts in order to protect public health
and safety. K. Provide development regulations and construction procedures which
will preserve, replace or enhance, to the maximum extent practicable,
existing vegetation, uplands, wetlands and water bodies. 99.20 Applicability. A. When
any provision of any other chapter of the Dunes City Code conflicts with
this chapter, that which provides more environmental protection shall
apply unless specifically provided otherwise in this chapter. B. The improvement of both public and private stormwater
management facilities through or adjacent to a new development shall be
the responsibility of the developer. Said improvements shall comply with
all applicable city ordinances, policies and standards.
Except as exempt under Chapter DCC 99.30, the standards in this
chapter apply to all applications for development submitted after the
effective date of this ordinance requesting approval of one or more of the
following: 1.
Land use application: Partition tentative plan, subdivision
tentative plan, planned unit development, tentative plan or site review. 2.
Development/Building Permit Application.
3.
Excavation, Grading, Driveway, or Access Permit Applications. 99.25
Financial Liability. A.
A surety bond shall be required for all projects to ensure
compliance with these standards. Bonds shall be set at 125 percent (%) of
the estimated cost of all stormwater-related improvements and the cost of
erosion/sedimentation control. B.
In lieu of a surety bond, the applicant may file a cash bond or
instrument of credit with the City Recorder in an amount equal to that
which would be required in a surety bond.
Dunes City Ordinance 135 and Am. Ord. 150. 99.30 Exemptions. The requirements and standards of
this chapter do not apply to: A. An
application that will result in the construction or creation of less than
five-hundred square feet (500 sf) of new or replaced impervious surface
area at full build out of the development. B. A
development/building permit application for any of the following:
1.
Development of a lot or parcel included in a land use application
that was determined by the city to comply with the standards in Chapter
DCC 99.55, Pollution Reduction Standards.
The approved land use application shall control development.
2. Development of a lot
or parcel that was not included in an application that was determined by
the city to comply with the standards in Chapter DCC 99.55 and will result
in less than five-hundred square feet (500 sf) of new or replaced
impervious surface within a 12 month period. 99.35
Illicit Discharges. Illicit
discharges to stormwater drainage systems are prohibited.
Subject to civil penalties, per Chapter DCC 99.90. 99.40
Abrogation and
Greater Restrictions. It is not
intended that this chapter repeal, abrogate, or impair any existing
regulations, easements, covenants, or deed restrictions. However, where
this chapter imposes greater restrictions, the provisions of this chapter
shall prevail. 99.45 Stormwater Best Management
Practices (BMPs). Best Management
Practices shall be used to control pollution from stormwater. BMPs shall
be used to comply with the standards in this chapter.
See Dunes City Stormwater Manual and Appendix F:
Oregon Department of Environmental Quality (DEQ) Erosion and Sediment
Control Manual. 99.50
Stormwater Containment and Destination Standards.
The purpose of these standards is to protect life, property and the
natural environment from flood and drainage hazards through the
establishment of containment and destination regulations for stormwater
runoff from development. A.
Stormwater Containment and Destination requirements apply to all
new development, except as exempted under Chapter DCC 99.30. B. No
construction or site disturbance for any new development that requires a
DEQ NPDES 1200-C Construction Stormwater Permit may begin before
applicant first obtains the permit and files a copy with the Dunes City
Planning Department. C.
Construction or Site Disturbance for any parcel that does not
require the 1200-C Construction Stormwater Permit, as a minimum, shall
adhere to the following BMPs and be required to control erosion and sediment during construction, to permanently stabilize
soil exposed during construction and to comply with site drainage
requirements 1 through 5 as follows, unless exempted under Chapter DCC
99.30. 1.
Construction vehicle access shall be, whenever possible, limited to one
route. Access points shall be
stabilized with quarry spall or crushed rock to minimize the tracking of
sediment onto public roads. 2.
All exposed soils shall be stabilized by suitable application of BMPs,
including but not limited to sod or other vegetation, plastic covering,
mulching, or application of ground base on areas to be paved. All BMPs
shall be selected, designed and maintained in accordance with an approved
manual. From October 1st through May 31st no soils shall remain exposed
for more than two days. From June 1st through
September 30th, no soils shall remain exposed for more than seven days. 3.
Adjacent
properties shall be protected from sediment deposition by appropriate use
of vegetative buffer strips, sediment barriers or filters, dikes or
mulching, or by a combination of these measures and other appropriate
BMPs. 4.
All
erosion and sediment control BMPs shall be regularly inspected and
maintained to ensure continued performance of their intended function. 5.
As
required by the manual, the Dunes City Council and the Health and Safety
Inspector can implement other appropriate BMPs in order to mitigate for
an event that results in an unanticipated increase in runoff. D. All
Stormwater facilities shall be designed and constructed in accordance with
the flood control design standards of this and the facility design
requirements set forth in the Stormwater Management Manual. E. An applicant
proposing new development must submit documentation to 1.
Contained on-site in accordance with Chapter DCC 99 and/or the
Stormwater Management Manual. 2.
Discharged off-site in accordance with Chapter DCC 99 and/or the
Stormwater Management Manual into an existing stormwater drainage facility
that has the capacity to accommodate the runoff from the proposed
development. In demonstrating
facility capacity, the evaluation shall include the runoff from all
current uses to the stormwater facility and runoff from new development
proposals that have already been approved by the City as of the date the
applicant submits a complete application. Prior
approvals shall include, but are not limited to, tentative plans and final
plats. Where off-site destination includes the direct discharge of runoff
into any water body, the proposal must comply with the Flow Control
requirements of Chapter DCC 99.60. 3.
If the applicant cannot demonstrate that existing stormwater
drainage facilities have adequate capacity to accommodate the proposed
runoff from the new development, the applicant must construct storm
drainage facilities with adequate capacity to accommodate the runoff from
the proposed development, or construct on-site containment facilities per
(#1) above. F. Stormwater runoff disposed of in underground systems may
also be regulated through the federal Underground Injection Control (UIC)
program under Part C of the Safe Drinking Water Act (42 U.S.C 300, 6A,
Subchapter XII) and Oregon Administrative Rule Chapter 340, Section 044.
99.55
Pollution Reduction Standards.
The purpose of this section is to protect public health by reducing
the introduction of pollution into the waters of the city.
A.
Land use and development applications shall include pollution
reduction facilities selected from the Stormwater Management Manual as
follows: 1.
For all land applications listed in Chapter DCC 99.50 B 1 and 3,
the selected pollution reduction facilities shall treat all the stormwater
runoff from the development site that will result from the design storm.
2.
For applications listed in Chapter DCC 99.50 B 1 and 3 that change
the area of impervious surfaces, the selected pollution reduction
facilities shall treat the stormwater runoff from the amended (added or
subtracted) impervious surfaces that will result from the design storm.
3.
For all Development/Building applications listed in Chapter DCC
99.50 B (2), applicants shall select pollution reduction facilities that
treat all stormwater runoff from all new or replaced impervious surface
area, or an equivalent on-site area, that will result from the design
storm. B. All pollution
reduction facilities shall be sited, designed, constructed, and maintained
according to the pollution reduction provisions and the facility design
requirements set forth in the Stormwater Management Manual.
C. The standards
of this section may be adjusted pursuant to the Stormwater Management
Manual and allow for the exceptions as indicated in Chapter DCC 99.30. 99.60
Flow Control Standards. The purpose of this section is to
protect water bodies from the erosive effects of increases in stormwater
runoff peak flow rates and volumes that result from the effects of
impervious surfaces and land disturbances.
A. All proposed
improvements that may create stormwater flows which drain into a stream,
pipe, or conduit shall demonstrate using methodology in the Stormwater
Management Manual that peak rates of flow delivered to an existing water
body will not increase during a design storm as a result of the proposed
development. B. For purposes
of designing the system as required by the standards in this section the
amount of impervious surface per lot is assumed to be the maximum allowed
lot coverage by structures plus all additional impervious surface
coverage. C. All
facilities to control the rate of stormwater runoff shall be sited,
designed and constructed according to the flow control provisions and the
facility design requirements set forth in the Stormwater Management
Manual. Flow control
facilities must be designed using one of the methodologies outlined in the
Stormwater Management Manual. D.
The standards in this section may be adjusted pursuant to
the Stormwater Management Manual. 99.65Stormwater
Source Controls. All source controls shall be
designed and constructed according to the source control provisions set
forth in the Stormwater Management Manual, except when the source control
would duplicate controls required by a state or federal permit, (i.e. DEQ
1200-C Permit) obtained by the applicant. Following
are some examples of areas where stormwater source controls are mandated.
A. Fuel
dispensing facilities and surrounding traffic areas where vehicles,
equipment or tanks are refueled on the premises.
A fuel dispensing facility is the area where fuel is transferred
from bulk storage tanks to vehicles, equipment, and/or mobile containers.
Exempt from these controls are propane tanks.
B. Exterior
storage of liquid materials, for example chemicals, food products, waste
oils, solvents or petroleum products in above ground containers, in
quantities of fifty gallons or more, including permanent and temporary
storage areas. Exempt from
this subsection are underground storage tanks or installations requiring a
Water Pollution Control Facility (WPCF) permit and containers with
internal protections. C. All
facilities that store solid waste. A
solid waste storage area is a place where solid waste containers,
including compactors, dumpsters, and garbage cans, are collectively
stored. Solid waste storage
areas include areas used to collect and store refuse or recyclable
materials collection areas. D. All
development that stockpiles or stores high-risk or low-risk bulk materials
in outdoor containers, as the terms “high-risk” and “low-risk” are
used in the Stormwater Management Manual.
Exempt from this subsection are:
1. Materials that have no measurable solubility or mobility in water and no hazardous, toxic or flammable properties. 2.
Materials that exist in gaseous form at ambient temperature.
3.
Materials, except for pesticides and fertilizers, which are
contained in a manner that prevents contact with stormwater.
E. All
development with a designated equipment or vehicle washing or steam
cleaning area. F. All
development projects that disturb property suspected or known to contain
contaminants in the soil or groundwater. 99.70
Stormwater Operations and Maintenance Standards. The purpose of this section is to
ensure that through adequate operation and maintenance, stormwater
facilities protect life and property from flood and drainage hazards and
provide protection for water bodies and the natural environment from the
erosive effects of runoff. A. Operation
and maintenance standards apply to all facilities designed and constructed
in accordance with this Section and the Stormwater Management Manual.
B. Unless
otherwise agreed, stormwater management facilities shall be privately
owned and shall be operated and maintained in accordance with this Chapter
and the Stormwater Management Manual.
C. The city
shall maintain public stormwater management facilities located on
city-owned property, city rights-of-way and city easements.
D. To ensure
that any city maintained stormwater management facility can be accessed by
the city for routine and/or emergency maintenance the applicant of an
applicable land use request or development permit must dedicate easements
approved by and to the city. E. If 99.75
Inspection.
A.
The B.
Inspections may include but are not limited to: routine
inspections, random inspections, inspections based upon complaints or
other notice of possible violations, inspections of drainage basins or
areas identified as higher than typical sources of sediment or other
contaminants or pollutants, or inspections of land uses that are of a type
associated with higher than usual discharges of contaminants or
pollutants. In addition,
inspections may include but are not limited to: reviewing maintenance and
repair records, sampling discharges, surface water, groundwater, and
material or water in drainage control facilities, and evaluating the
condition of drainage control facilities and other stormwater treatment
practices. C. When any new
stormwater management facility is installed on private property, or when
any new connection is made between private property and a public drainage
control system, the property owner shall grant Dunes City the right to
enter the property at reasonable times and in a reasonable manner for the
purpose of inspection, abatement of a public nuisance or correction or
investigation of a violation of this Chapter. D. Should entry
be refused, the Health and Safety Inspector shall have recourse to the
remedies provided by law to secure entry. ( E. Liability
for Health and Safety Inspector will be the same as that designated under
Chapter DCC 151 §151.078. 99.80
Enforcement. A.
Failure to construct, operate and maintain source controls as set
forth in this Chapter shall be unlawful and a civil infraction subject to
the enforcement provisions of Chapter DCC 36. B. If,
at any time C. The choice of enforcement
action and the severity of any penalty shall be based on Chapter DCC 177
§1-B. 99.85
Stop work
order. The Health and
Safety Inspector shall have the authority to serve a person a stop work
order if an action is being undertaken in violation of this Chapter. If a
portion of a project is in violation of this Chapter, the inspector may
issue a stop work order for the entire project. A. The
order shall contain: 1.
A description of the specific nature, extent and time of violation,
and the damage or potential damage. 2.
A notice that the violation or the potential violation must cease
and desist, and, in appropriate cases, the specific corrective action to
be taken within a given time. A civil penalty under Chapter DCC 36 and
Chapter DCC 10.99 may be issued with the order. B.
Notice. A stop work order
shall be imposed by a notice in writing, either by certified mail with
return receipt requested, or by personal service, to the person incurring
the same or by being posted on the work site. The certified mailing will
be sent to the responsible party’s address on file with the City.
C. Effective
Date. The stop work order issued under this Chapter shall become effective
immediately upon receipt by the person to whom the order is directed or
within five (5) days of the mailing of the certified notice or when posted
on the work site. D. Compliance.
Failure to comply with the terms of a stop work order shall result in
enforcement actions including, but not limited to the issuance of a civil
penalty pursuant to Chapter DCC 36.
E. Final approval
shall not be granted until corrections to all stormwater improvements have
been made and accepted by F. A Stop Work
Order Hearing may be held pursuant to Chapter DCC 155.1.4.8 (B). 99.90 Civil penalty. A person who
fails to comply with the requirements of this Chapter, who fails to
conform to the terms of an approval or order issued, who undertakes new
development without first obtaining city approval, or who fails to comply
with a stop work order issued under these regulations shall be subject to
a civil penalty pursuant to Chapter DCC 36. A.
Amount of Penalty. The minimum penalty shall be $500.00 and the
maximum penalty $2,500 for each violation as determined by the Health and
Safety Inspector and/or the City Council. Each day of continued violation
or repeated violation shall constitute a separate violation.
Fines will be consistent with those contained in Chapter DCC
General Provisions; §10.99 and Chapter DCC 36 §36.14. B.
Aiding or Abetting. Any
person who, through an act of commission or omission, aids or abets in the
violation shall be considered to have committed a violation for the
purposes of the civil penalty. C.
Fine Imposition. Reference:
Chapter DCC 36 §36.12. D.
Appeals: Reference:
Chapter DCC 36 §36.13. 99.95
Penalties
Due. Penalties for
violations of this chapter shall become due and payable 10 days after
receipt of written notice of the violation, unless an appeal is filed
pursuant to Chapter DCC 36 § 36.13. Failure
to pay such fine, shall constitute a violation against the city and
subject to a civil penalty as provided in Chapter 36 § 36.99. 99.100
Exceptions. After a public
hearing, the city council may grant an exception from the requirements of
this Chapter. In granting any
exception, the city council may prescribe conditions that are deemed
necessary or desirable for the public interest. 99.105
Finding of Fact (Exceptions). Exceptions to
the minimum requirements of stormwater source control (Chapter 99.65) may
be granted prior to permit approval and construction. An exception may be
granted following a public hearing, provided that a written finding of
fact is prepared, that addresses the following: A. The
exception provides equivalent environmental protection and is in the
overriding public interest, and that the objectives of safety, function,
environmental protection and facility maintenance, based upon sound
engineering, are fully met. B.
That there are special physical circumstances or conditions
affecting the property such that the strict application of these
provisions would deprive the applicant of all reasonable use of the parcel
of land in question, and every effort to find creative ways to meet the
intent of the minimum standards has been made. C.
That the granting of the exception will not be detrimental to the
public health and welfare, nor injurious to other properties in the
vicinity and/or downstream, and to the quality of waters of the state. D. The
exception is the least possible exception that could be granted to comply
with the intent of the minimum requirements. 99.110
Prior Approval. Any exception
shall be approved prior to permit approval and construction. 99.115
Duration of Exception. Exceptions
granted shall be valid for two years, unless granted for a shorter period. 99.120
Right of Appeal. All actions of
the city council, except those involving a civil penalty (Chapter DCC 36
§36.13), shall be final and conclusive, unless within 10 days of the date
of the city council’s action, the original applicant or an adverse party
gives written notice of appeal to the Superior Court of Lane County for
review of the action. 99.125
Adjustment Review – Approval Criteria. The Health and Safety Inspector
shall approve, conditionally approve, or deny an adjustment review
application for Stormwater Containment and Destination, Pollution
Reduction, Flow Control and Source Control Standards.
Approval or conditional approval shall be based on compliance with
the following applicable criteria. A.
The requirement in Chapter DCC 99- 1.
The area generating untreated runoff is less than five-hundred
square feet (500 sf) of impervious surface and is isolated from the
pollution reduction facility. 2.
The area generating untreated runoff is less than five-hundred
square feet (500 sf) of impervious surface and it is not technically
feasible to drain the untreated runoff to the pollution reduction
facility. 3.
The area generating runoff is less than five-hundred square feet
(500 sf) and constructing pollution reduction facilities to treat the
runoff from the area at issue would require removal of trees or damage to
other natural resources. 4.
The area generating untreated runoff is less than five-hundred
square feet (500 sf) of impervious surface and limited access to the area
would prevent regular maintenance of the pollution reduction facility. B. The
requirement in Chapter DCC 99.55 B that all pollution reduction facilities
be sited, designed and constructed according to the pollution reduction
provisions and the facility design requirements set forth in the
Stormwater Management Manual may be adjusted.
This adjustment shall be based upon findings that all of the
following requirements are met: 1.
The proposed alternative design will achieve equal or superior
results for pollution reduction function, maintainability and safety and
the proposed site location does not adversely affect structures or other
properties. 2.
The applicant’s written description of the proposed alternative
design has been reviewed and approved by the Health and Safety Inspector
and City Engineer. The description of the proposed design submitted for
review must include all of the following information for each component of
the proposed alternative design: (a) Size, technical description, capacity, capital cost, design life, construction process and costs, consequences of improper construction, operation and maintenance requirements and costs. (b)
Data on the effectiveness of proposed alternative technologies, if
available, including data from laboratory testing and pilot/full-scale
operations, and information regarding the operations of any full-scale
installations. (c)
Any other available information about the proposed design,
including peer reviewed articles, scientific or engineering journals, and
approvals from other jurisdictions. 3.
The applicant has submitted a method and schedule for monitoring
the effectiveness of the proposed design once constructed and a schedule
for its maintenance. 4.
The applicant has submitted a signed statement that the applicant
will replace the alternative pollution reduction facility if it does not
function as proposed. The
applicant will be required to post a surety bond as per section Chapter
DCC 99.25. C. The
requirements in Chapter DCC 99.60 that Flow Control Standards and Chapter
DCC 99.65 Source Control Standards be sited, designed and constructed
according to the provisions and the facility design requirements as set
forth in the Stormwater Management Manual.
Any adjustment will only be made if the applicant can demonstrate
that the selected flow control facility will achieve the same result or a
better result as those listed in the Stormwater Management Manual.
99.130
Stormwater Management Manual. In order to implement Chapter DCC
99.05 through 99.135, the A. Reduce runoff
pollution from development by reducing the overall amount of impervious
surface area and extent of connectedness to downstream drainages. B. Emphasize
stormwater management facilities that, to the maximum extent practicable,
retain and treat stormwater utilizing on-site controls. C. Emphasize
stormwater management facilities that incorporate vegetation as a key
element and include design and construction requirements that ensure
landscape plant survival and overall stormwater facility function success. D. Operate and
maintain stormwater management facilities in accordance with
facility-specific Operation and Maintenance Plans. E. Reduce
pollutants of concern that are generated by identified site uses and site
characteristics that are not addressed solely through the pollution
reduction measure by implementing additional specific source control
methods including reducing or eliminating pathways that may introduce
pollutants into stormwater and avoiding preventable discharges to surface
waters or groundwater. F. The
Stormwater Management Manual includes a list of scientifically accepted
stormwater treatment practices, including the specific design criteria for
each stormwater practice. The
manual may be updated and expanded from time to time, at the discretion of
the City of Dunes City, based on improvements in engineering, science,
monitoring and local maintenance experience. 99.135 Definitions. For the purposes of this chapter, the following definitions shall apply: “Approval”
The proposed work or completed
work conforms to this chapter in the opinion of the director. “Best
management practices” or “BMPs”
Physical, structural,
and/or managerial practices that, when used singly or in combination,
prevent or reduce pollution of water. BMPs are listed and described in the
stormwater manual. “Clearing”
The destruction and removal of
vegetation by manual, mechanical, or chemical methods. “Comprehensive
Plan” The
Dunes City plan to control and promote development which is most desirable
to the majority of the residents and property owners of the City.
The Plan establishes a set of policies and guidelines which would
allow for development to occur while preserving those qualities which
brought them to the community or has made the community what it is today. “Design
storm” A
prescribed hyetograph (see
description) and total precipitation amount (for a specific duration
recurrence frequency) used to estimate runoff for a hypothetical storm of
interest or concern for the purposes of analyzing existing drainage,
designing new drainage facilities or assessing other impacts of a proposed
project on the flow of surface water. A
hyetograph is a graph of percentages of total precipitation for a series
of time steps representing the total time during which the precipitation
occurs. “Detention”
The release of stormwater
runoff from the site at a slower rate than it is collected by the
stormwater facility system, the difference being held in temporary
storage. “Detention
facility”
An above or below ground facility, such as a pond or tank, that
temporarily stores stormwater runoff and subsequently releases it at a
slower rate than it is collected by the drainage facility system.
There is little or no filtering of stored stormwater. “Development” All
improvements on a site, including buildings, other structures, parking and
loading areas, landscaping, paved or graveled areas, grading and areas
devoted to exterior display, storage, or activities.
Development includes improved open areas such as plazas and
walkways, but does not include natural geologic forms or landscapes. “Drainage
basin” A
geographic and hydrologic subunit of a watershed. “Erosion”
The wearing away of the land
surface by running water, wind, ice, or other geological agents, including
such processes as gravitational creep. “Erosion” also means the
detachment and movement of soil or rock fragments by water, wind, ice, or
gravity. “Excavation”
The mechanical removal
of earth material. “Existing
site conditions” 1.
For developed sites with stormwater facilities that have been constructed
to meet the standards in the minimum requirements of the manual, existing
site conditions shall mean the existing conditions on the site. 2.
For developed sites that do not have stormwater facilities that meet the
minimum requirements, existing site conditions shall mean the conditions
that existed prior to local government adoption of a stormwater management
program. If in question, the
existing site conditions shall be documented by aerial photograph records
or other appropriate means. 3.
For all
undeveloped sites, existing site conditions shall mean the existing
conditions on the site. “Flow Control Facility”
Any structure or drainage device that is designed,
constructed, and maintained to collect, retain, infiltrate, or detain
surface water runoff during and after a storm event for the purpose of
controlling flow rate and volume leaving the site. “Groundwater”
Water in a saturated zone or stratum beneath the surface of land or
a surface water body. “Hyetograph”
A
graphical representation of the distribution of rainfall over the total
duration of a storm event. For example, in the 24-hour rainfall
distributions as developed by the Soil Conservation Service (now the NRCS
or National Resources Conservation Service), rainfall intensity
progressively increases until it reaches a maximum and then gradually
decreases. Where this maximum occurs and how fast the maximum is reached
is what differentiates one distribution from another. One important aspect
to understand is that the distributions are for design storms.
Design storms are theoretical storms (not necessarily actual
storms). In other words, a real storm may not behave in this same fashion.
The maximum intensity may not be reached as uniformly as shown in the SCS
hyetographs. “Illicit
Discharge” All
non-stormwater discharges to stormwater drainage systems that cause or
contribute to a violation of state water quality, sediment quality or
ground water quality standards, including but not limited to septic system
affluent, industrial process water, interior floor drains, car washing and
greywater systems. “Impervious
Surface” A
surface area which either prevents or retards the entry of water into the
soil mantle as under natural conditions prior to development, and/or a
surface area which causes water to run off the surface in greater
quantities or at an increased rate of flow from the flow present under
natural conditions prior to development. Common impervious surfaces
include, but are not limited to, roof tops, walkways, patios, driveways,
parking lots or storage areas (gravel or paved), concrete or asphalt
paving, gravel roads or driveways, packed earthen materials, and oiled,
macadam or other surfaces which similarly impede the natural infiltration
of stormwater. Open, uncovered retention/detention facilities shall not be
considered as impervious surfaces. Note:
Slatted decks are considered pervious surfaces. Gravel surfaces are
considered pervious surfaces unless they cover impervious surfaces or are
compacted to a degree that causes their run-off coefficient to exceed
eighty percent (80%). “Mitigation”
In the following order of
preference: 1.
Avoiding the impact altogether by not taking a certain action or part of
an action. 2.
Minimizing impacts by limiting the degree or magnitude of the action and
its implementation, by using appropriate technology, or by taking
affirmative steps to avoid or reduce impacts. 3.
Rectifying the impact by repairing, rehabilitating or restoring the
affected environment. 4.
Reducing or eliminating the impact over time by preservation and
maintenance operations during the life of the action. 5.
Compensation for the impact by replacing, enhancing, or providing
substitute resources or environments. “New
Development” The
following activities: land disturbing activities, structural development,
including construction, installation or expansion of a building or other
structure, creation of impervious surfaces and Class IV-general forest
practices that are conversions from timber land to other uses and
subdivision of land. All
other forest practices and commercial agriculture are not considered new
development. “Person”
Any individual,
partnership, corporation, association, organization, cooperative, public
or municipal corporation, agency of the state, or local government unit,
however designated. “Pollution”
Contamination or other
alteration of the physical, chemical, or biological properties of waters
of the state, including change in temperature, taste, color, turbidity, or
odor of the waters, or such discharge of any liquid, gaseous, solid,
radioactive or other substance into any waters of the State as will or is
likely to create a nuisance or render such waters harmful, detrimental or
injurious to the public health, safety or welfare, or to domestic,
commercial, industrial, agricultural, recreational, or other legitimate
beneficial uses, or to livestock, wild animals, birds, fish or other
aquatic life. “Pollution
Reduction Facility” Any
structure or drainage device that is designed, constructed, and maintained
to collect and filter, retain, or detain surface water runoff during and
after a storm event for the purpose of maintaining or improving surface
and/or groundwater quality. “Property suspected or known to contain contaminants in
the soil or groundwater” Any
real property where the presence of any hazardous substance or petroleum
product indicates an existing release, past release, or threatened release
of a hazardous substance or petroleum product into the ground,
groundwater, or surface water of the property “Redevelopment”
On an already developed
site, the creation or addition of impervious surfaces, structural
development including construction, installation or expansion of a
building or other structure, and/or replacement of an impervious surface
that is not part of a routine maintenance activity and land disturbing
activities associated with structural or impervious redevelopment. “Runoff”
Water from rainfall,
snow melt, or otherwise discharged that flows across the ground surface
instead of infiltrating the ground. “Site”
The portion of a piece of property that is directly subject to
development. “Soil”
The unconsolidated
mineral and organic material on the immediate surface of the earth that
serves as a natural medium for the growth of land plants. "Source
Control” Any
structure, device, or design that is used to eliminate or reduce
stormwater pollution from a known source. “Stormwater”
That portion of
precipitation that does not naturally percolate into the ground or
evaporate and is discharged from a surface, including, but not limited to,
flows into defined surface water channels, water bodies, pipes or
constructed infiltration facilities. “Stormwater
drainage system”
Describes constructed
and natural features which function together as a system to collect,
convey, channel, hold, inhibit, retain, detain, infiltrate, divert, treat
or filter stormwater. “Stormwater Management Manual” The
most recent version of the
Dunes City Stormwater Management Manual as adopted by the city.
“Stormwater Management Facility” Any
structure or configuration of the ground that is used or, by its location,
becomes a place where stormwater flows or is accumulated, including but
not limited to pipes, curbs, gutters, catch basins, ponds, open drainage
ways, runoff control facilities, wetlands and their accessories. “Water
body” All
surface waters including rivers, streams, lakes, marine waters, estuaries,
and wetlands. “Watershed”
A geographic region
within which water drains into a particular river, stream, or body of
water. “Vegetation”
All organic plant life
growing on the surface of the earth. |