This chapter implements applicable provisions of the local coastal
program for ensuring the protection of the quality of coastal waters
by providing standards for the review, authorization, and conditioning
of new development and land uses consistent with the requirements
of the California Coastal Act.
(Ord. of 2-22-2011(1))
The provisions of this chapter apply to the review of coastal
development permit applications for all development or uses proposed
on sites that entails construction, grading, or other activities that
involve ground disturbance, increases in impervious surface areas,
or alterations in the direction, volume, or flow rate of surface or
groundwater hydrology.
(Ord. of 2-22-2011(1))
In addition to the information required by Section 17.84.020 for coastal development permit applications, the applicant shall provide the following supplemental information:
A.
Construction
pollution control plan. A construction-phase erosion, sedimentation,
and polluted runoff control plan ("construction pollution control
plan") shall specify interim best management practices (BMPs) that
will be implemented to minimize erosion and sedimentation during construction,
and prevent contamination of runoff by construction chemicals and
materials, to the maximum extent practicable. The construction pollution
control plan shall demonstrate that:
1.
During construction, development shall minimize site runoff and erosion
through the use of temporary BMPs (including, but not limited to,
soil stabilization measures), and shall eliminate the discharge of
sediment and other stormwater pollution resulting from construction
activities (e.g., chemicals, vehicle fluids, asphalt and cement compounds,
and debris), to the extent feasible.
2.
Land disturbance activities during construction (e.g., clearing,
grading, and cut-and-fill) shall be minimized, to the extent feasible,
to avoid increased erosion and sedimentation. Soil compaction due
to construction activities shall be minimized, to the extent feasible,
to retain the natural stormwater infiltration capacity of the soil.
3.
Construction shall minimize the disturbance of natural vegetation
(including significant trees, native vegetation, and root structures),
which is important for preventing erosion and sedimentation.
4.
Development shall implement soil stabilization BMPs, including but
not limited to re-vegetation, on graded or disturbed areas as soon
as feasible.
5.
Grading operations shall not be conducted during the rainy season
(from October 1 to April 15), except in response to emergencies, unless
the County determines that soil conditions at the project site are
suitable, the likelihood of significant precipitation is low during
the period of extension, (not to exceed one week at a time), and adequate
erosion and sedimentation control measures will be in place during
all grading operations.
6.
The construction pollution control plan shall be submitted with the
final construction drawings. The plan shall include, at a minimum,
a narrative report describing all temporary polluted runoff, sedimentation,
and erosion control measures to be implemented during construction,
including:
a.
Controls to be implemented on the amount and timing of grading.
b.
BMPs to be implemented for staging, storage, and disposal of excavated
materials.
c.
Design specifications for structural treatment control BMPs, such
as sedimentation basins.
d.
Re-vegetation or landscaping plans for graded or disturbed areas.
e.
Other soil stabilization BMPs to be implemented.
f.
Methods to infiltrate or treat stormwater prior to conveyance off-site
during construction.
g.
Methods to eliminate or reduce the discharge of other stormwater
pollutants resulting from construction activities (including but not
limited to paints, solvents, vehicle fluids, asphalt and cement compounds,
and debris) into stormwater runoff.
h.
BMPs to be implemented for staging, storage, and disposal of construction
chemicals and materials.
i.
Proposed methods for minimizing land disturbance activities, soil
compaction, and disturbance of natural vegetation.
j.
A site plan showing the location of all temporary erosion control
measures.
k.
A schedule for installation and removal of the temporary erosion
control measures.
7.
A list of "good housekeeping" provisions including but not limited
to inventory of products and chemicals used on site, plans for the
cleanup of spill and leaks, and on site inspections by a qualified
sediment and water quality control specialist.
B.
Post-Construction
Stormwater Plan. A plan to control post-construction stormwater runoff
flows, and maintain or improve water quality ("post-construction stormwater
plan") shall specify site design, source control, and if necessary,
treatment control BMPs that will be implemented to minimize stormwater
pollution and minimize or eliminate increases in stormwater runoff
volume and rate from the development after construction. Water quality
treatment BMPs shall prioritize the integration of site design BMPs
over source control BMPs over treatment control BMPs. The post-construction
stormwater plan shall demonstrate that:
1.
Following construction, erosion on the site shall be controlled to
avoid adverse impacts on adjacent properties and resources.
2.
Permanent erosion control measures shall be installed, as may be
needed, depending upon the intensity of development proposed and the
sensitivity of receiving waters.
3.
Runoff from the project shall not increase sedimentation in receiving
waters.
4.
On-site filtering, grease, and/or sediment trapping systems shall
be installed, as needed, to capture any pollutants contained in the
runoff.
5.
Permanent runoff/drainage control improvements, such as subsurface
drainage interception, energy dissipaters, recovery/reuse cisterns,
detention/retention impoundments, etc. shall be installed, as needed,
at the point of discharge.
6.
In the application and initial planning process, the applicant shall
submit a preliminary postconstruction stormwater plan, and prior to
issuance of a building permit the applicant shall submit a final post-construction
stormwater plan for approval by the County. The plan shall include,
at a minimum, the following components:
a.
Proposed site design and source control BMPs that will be implemented
to minimize postconstruction polluted runoff.
b.
Proposed drainage improvements (including locations of infiltration
basins, and diversions/ conveyances for upstream runoff).
c.
Measures to maximize on-site retention and infiltration (including
directing rooftop runoff to permeable areas rather than to driveways).
d.
Measures to maximize, to the extent practicable, the percentage of
permeable surfaces, and to limit the percentage of directly connected
impervious areas, to increase infiltration of runoff.
e.
Methods to convey runoff from impervious surfaces into permeable
areas of the property in a non-erosive manner.
f.
A site plan showing the location of all permanent erosion control
measures.
g.
A schedule for installation and maintenance of the permanent erosion
control measures.
h.
A schedule for installation and maintenance of the sediment and debris
filtration, grease and/or sediment trap, etc., as warranted for the
type of development and site.
i.
A site plan showing finished grades in one-foot contour intervals
and associated drainage improvements.
C.
Site
design using low impact development techniques. The post-construction
stormwater plan shall demonstrate the preferential consideration of
low impact development (LID) techniques in order to minimize stormwater
quality and quantity impacts from development. LID is a development
site design strategy with a goal of maintaining or reproducing the
site's pre-development hydrologic functions of storage, infiltration,
and groundwater recharge, as well as the volume and rate of stormwater
discharges. LID strategies use small-scale integrated and distributed
management practices, including minimizing impervious surfaces, infiltrating
stormwater close to its source, and preservation of permeable soils
and native vegetation. LID techniques to consider include, but are
not limited to, the following:
1.
Development shall be sited and designed to preserve the infiltration,
purification, detention, and retention functions of natural drainage
systems that exist on the site, to the maximum extent practicable.
Drainage shall be conveyed from the developed area of the site in
a non-erosive manner.
2.
Development shall minimize the creation of impervious surfaces (including
pavement, sidewalks, driveways, patios, parking areas, streets, and
roof-tops), especially directly connected impervious areas, to the
maximum extent practicable. Directly connected impervious areas include
areas covered by a building, impermeable pavement, and/or other impervious
surfaces, which drain directly into the storm drain system without
first flowing across permeable land areas (e.g., lawns)
3.
Development shall maintain or enhance, where appropriate and feasible,
on-site infiltration of stormwater runoff, in order to preserve natural
hydrologic conditions, recharge groundwater, attenuate run-off flow,
and minimize transport of pollutants.
Alternative management practices shall be substituted where
the Public Works Director has determined that infiltration BMPs may
result in adverse impacts, including but not limited to where saturated
soils may lead to geologic instability, where infiltration may contribute
to flooding, or where regulations to protect groundwater may be violated.
4.
Development that creates new impervious surfaces shall divert stormwater
runoff flowing from these surfaces into permeable areas in order to
maintain, or enhance where appropriate and feasible, on-site stormwater
infiltration capacity.
5.
To enhance stormwater infiltration capacity, development applicants
shall use permeable pavement materials and techniques (e.g., paving
blocks, porous asphalt, permeable concrete, and reinforced grass or
gravel), where necessary to retain water or reduce the rate of runoff.
Permeable pavements shall be designed so that stormwater infiltrates
into the underlying soil, to enhance groundwater recharge and provide
filtration of pollutants.
D.
Water
quality and hydrology plan for developments of water quality concern.
In addition to the information to be provided in the post-construction
stormwater plan, applicants for "developments of water quality concern,"
shall submit a water quality and hydrology plan and be subject to
the additional requirements listed below.
1.
"Developments of water quality concern" include the following:
a.
Housing developments of ten or more dwelling units, including, but
not limited to, residential subdivisions.
b.
Developments that result in the creation, addition, or replacement
of ten thousand square-feet or more of impervious surface area.
c.
Parking lots with five thousand square feet or more of impervious
surface area, potentially exposed to stormwater runoff.
d.
Vehicle service facilities, including retail gasoline outlets, commercial
car washes, and vehicle repair facilities.
e.
Industrial parks, commercial strip malls, or restaurants with five
thousand square feet or more of impervious surface area.
f.
Commercial or industrial outdoor storage areas of five thousand square
feet or more, or as determined by the county based on the use of the
storage area, where used for storage of materials that may contribute
pollutants to the storm drain system or coastal waters.
g.
Heavy industrial developments.
h.
Streets, roads, highways, and freeway construction of five thousand
square feet or more of impervious surface area, but not including
stand-alone pedestrian pathways, trails, and off-street bicycle lanes.
i.
All developments entailing the creation, addition, or replacement
of two thousand five hundred square feet or more of impervious surface
area, located within one hundred twenty-five feet of the ocean or
a coastal waterbody (including estuaries, wetlands, rivers, streams,
and lakes), or that discharge directly to the ocean or a waterbody
(i.e., outflow from the drainage conveyance system is composed entirely
of flows from the subject development or redevelopment site, and not
commingled with flows from adjacent lands.)
2.
Additional Requirements for developments of water quality concern:
a.
Water quality and hydrology plan. The applicant for a development
of water quality concern shall be required to submit a water quality
and hydrology plan (WQHP), prepared by a California Professional Engineer,
Professional Geologist or Engineering Geologist, or California Landscape
Architect, which supplements the post-construction stormwater plan.
The WQHP shall include calculations, per County standards, that estimate
increases in pollutant loads and changes in stormwater runoff hydrology
(i.e., volume and flow rate) resulting from the proposed development,
and shall specify the BMPs that will be implemented to minimize post-construction
water quality and hydrologic impacts. The WQHP shall also include
operation and maintenance plans for post-construction treatment control
BMPs. In the application and initial planning process, the applicant
shall be required to submit for approval a preliminary WQHP, and prior
to issuance of a building permit the applicant shall submit a final
WQHP for approval by the County Engineer.
b.
Selection of structural treatment control BMPs. If the County determines
that the combination of site design and source control BMPs is not
sufficient to protect water quality and coastal waters, a structural
treatment control BMP (or suite of BMPs) shall also be required. Developments
of water quality concern are presumed to require treatment control
BMPs to meet the requirements of the coastal land use plan and state
and federal water quality laws, unless the water quality and hydrology
plan demonstrates otherwise.
The water quality and hydrology plan for a development of water
quality concern shall describe the selection of treatment controls
BMPs. Applicants shall first consider the treatment control BMP, or
combination of BMPs, that is most effective at removing the pollutant(s)
of concern, or provide a justification if that BMP is determined to
be infeasible.
c.
Eighty-fifth percentile design standard for treatment control BMPs.
For post-construction treatment of stormwater runoff in developments
of water quality concern, treatment control BMPs (or suites of BMPs)
shall be sized and designed to treat, infiltrate, or filter the amount
of stormwater runoff produced by all storms up to and including the
eighty-fifth percentile, twenty-four-hour storm event for volume-based
BMPs, and/or the eighty-fifth percentile, one-hour storm event (with
an appropriate safety factor of two or greater) for flow-based BMPs.
d.
Maintain pre-development hydrograph. In developments of water quality
concern where changes in stormwater runoff hydrology (i.e., volume
and flow rate) may result in increased potential for streambank erosion,
downstream flooding, or other adverse habitat impacts, hydrologic
control measures (e.g., stormwater infiltration, detention, harvest
and re-use, and landscape evapotranspiration) shall be implemented
in order to ensure that the pre- and post-project runoff hydrographs
match within ten percent for a two-year return frequency storm.
5.
Content. The water quality and hydrology plan shall
contain the following:
a.
Site design, source control, and treatment control BMPs that will
be implemented to minimize post-construction water quality and hydrologic
impacts.
b.
All of the information required in sub-section A for the post-construction
stormwater plan.
c.
Pre-development stormwater runoff hydrology (i.e., volume and flow
rate) from the site.
d.
Expected post-development stormwater runoff hydrology (i.e., volume
and flow rate) from the site, with all proposed non-structural and
structural BMPs in place.
e.
Measures to infiltrate or treat runoff from impervious surfaces (including
roads, driveways, parking structures, building pads, roofs, and patios)
on the site, and to discharge the runoff in a manner that avoids potential
adverse impacts. Such measures may include, but are not limited to,
structural treatment control BMPs including biofilters, grassy swales,
on-site de-silting basins, detention ponds, or dry wells.
f.
A description of how the BMPs (or suites of BMPs) have been designed
to infiltrate and/or treat the amount of storm water runoff produced
by all storms up to and including the eighty-fifth percentile, twenty-four-hour
storm event for volume-based BMPs, and/or the eighty-fifth percentile,
one-hour storm event (with an appropriate safety factor of two or
greater) for flow-based BMPs.
g.
Appropriate structural post-construction Treatment Control BMPs selected
to remove the specific runoff pollutants generated by the development,
using processes such as gravity settling, filtration, biological uptake,
media adsorption, or any other physical, chemical, or biological process.
h.
A long-term plan and schedule for the monitoring and maintenance
of all structural Treatment Control BMPs. All structural BMPs shall
be inspected, cleaned, and repaired as necessary to ensure their effective
operation for the life of the development. Owners of these devices
shall be responsible for ensuring that they continue to function properly,
and additional inspections should occur after storms as needed throughout
the rainy season. Repairs, modifications, or installation of additional
BMPs, as needed, shall be carried out prior to the next rainy season.
E.
Best
management practices (BMPs); selection and incorporation.
1.
All development shall incorporate effective site design and long-term
post-construction source control BMPs, as necessary to minimize adverse
impacts to water quality and coastal waters resulting from the development,
to the maximum extent practicable. BMPs that protect post-construction
water quality and minimize increases in runoff volume and rate shall
be incorporated as necessary in the project design of developments
in the following order of priority:
a.
Site design BMPs: Project design features that reduce the creation
or severity of potential pollutant sources, or reduce the alteration
of the project site's natural stormwater flow regime. Examples are
minimizing impervious surfaces, preserving native vegetation, and
minimizing grading.
b.
Source control BMPs: Methods that reduce potential pollutants at
their sources and/or avoid entrainment of pollutants in runoff, including
schedules of activities, prohibitions of practices, maintenance procedures,
managerial practices, or operational practices. Examples are covering
outdoor storage areas, use of efficient irrigation, and minimizing
the use of landscaping chemicals.
c.
Treatment control BMPs: Systems designed to remove pollutants from
stormwater, by simple gravity settling of particulate pollutants,
filtration, biological uptake, media adsorption, or any other physical,
biological, or chemical process. Examples are vegetated swales, detention
basins, and storm drain inlet filters.
2.
The selection of BMPs shall be guided by the California Stormwater
Quality Association (CAS-QA) Stormwater BMP Handbooks dated January
2003 (or the current edition), or an equivalent BMP manual that describes
the type, location, size, implementation, and maintenance of BMPs
suitable to address the pollutants generated by the development and
specific to a climate similar to Del Norte County's. Caltrans' 2007
"Storm Water Quality Handbook: Project Planning and Design Guide"
(or the current edition) may also be used to guide design of construction-phase
BMPs. Additional guidance on BMPs is available from the state water
resources and water quality boards, the U.S. Environmental Protection
Agency, regional entities such as the Bay Area Stormwater Management
Agencies Association's (BASMAA) "Start at the Source: Design Guidance
Manual for Stormwater Quality Protection," and/or as may be developed
from time to time with technological advances in water quality treatment.
3.
Where BMPs, are required, BMPs shall be selected that have been shown
to be effective in reducing the pollutants typically generated by
the proposed land use. The strategy for selection of appropriate BMPs
to protect water quality and coastal waters shall be guided by Tables
17.84B-1 through 3, below, or equivalent tables which list pollutants
of concern and appropriate BMPs for each type of development or land
use.
(Ord. of 2-22-2011(1))
In addition to the findings for approval or conditional approval of a coastal development permit, development authorization, or other entitlement as required by Section 17.84.033, the following supplementary findings, based on factual evidence, shall be made for new development or uses having potential impacts to the quality of coastal waters:
A.
Generally. All approved development will be, or has been conditioned to be, consistent with the development standards of Section 17.84B.050, as applicable.
(Ord. of 2-22-2011(1))
A.
Development
shall be undertaken in accordance with the approved erosion and stormwater
control final plans and/or water quality management plan. Any proposed
changes to the approved final plans shall be reported to the director.
No changes to the approved final plans shall occur without an amendment
to the coastal development permit, or equivalent, unless the director
determines that no amendment is legally required.
|
Table 17.84B-1: Pollutants Generated by Development Category
| |||||||||
|---|---|---|---|---|---|---|---|---|---|
|
Pollutants generated by various development categories include,
but are not limited to:
| |||||||||
|
Development Categories
|
Sediments
|
Nutrients
|
Heavy Metals
|
Organic Compounds
|
Trash and Debris
|
Oxygen Demanding Substances
|
Oil and Grease
|
Bacteria and Viruses
|
Pesticides
|
|
Detached Residential Developments
|
X
|
X
|
|
|
X
|
X
|
X
|
X
|
X
|
|
Attached Residential Developments
|
X
|
X
|
|
|
X
|
P(1)
|
P(2)
|
P
|
X
|
|
Commercial Developments >100,000 ft2
|
P(1)
|
P(1)
|
|
P(2)
|
X
|
P(5)
|
X
|
P(3)
|
P(5)
|
|
Automotive Service Facilities
|
|
|
X
|
X(4)(5)
|
X
|
|
X
|
|
|
|
Retail Gasoline Outlets
|
|
|
X
|
X(4)(5)
|
X
|
|
X
|
|
|
|
Restaurants
|
|
|
|
|
X
|
X
|
X
|
X
|
|
|
Hillside Developments
|
X
|
X
|
|
|
X
|
X
|
X
|
|
X
|
|
Parking Lots
|
P(1)
|
P(1)
|
X
|
|
X
|
P(1)
|
X
|
|
P(1)
|
|
Streets, Highways and Freeways
|
X
|
P(1)
|
X
|
X(4)
|
X
|
P(5)
|
X
|
|
|
|
Notes:
| |
|---|---|
|
X = anticipated P
= potential
| |
|
(1)
|
A potential pollutant if landscaping exists on-site
|
|
(2)
|
A potential pollutant if the project includes uncovered parking
areas
|
|
(3)
|
A potential pollutant if land use involves food or animal waste
products
|
|
(4)
|
Including petroleum hydrocarbons
|
|
(5)
|
Including solvents
|
|
Table adapted from the city of Carpinteria's Water Quality Protection
Ordinance.
| |
|
Table 17.84C-2: Areas for Site Design and Source Control BMP
Implementation by Development Category
| ||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
Specific areas for implementation of Site Design and Source
Control BMPs include, but are not limited to:
| ||||||||||||||
|
Development Categories
|
Private Roads
|
Residential Driveways and Guest Parking
|
Loading/Unloading Dock Areas
|
Repair/Main-tenance Bays
|
Vehicle Wash Areas
|
Outdoor Process-ing Areas
|
Equip-ment Wash Areas
|
Parking Areas
|
Roadways
|
Fueling Areas
|
Hillside Land-scaping
|
Outdoor Material Storage Areas
|
Trash Storage Areas
|
Pools and Spas
|
|
Detached Residential Developments
|
R
|
R
|
|
|
|
|
|
|
|
|
R
|
|
|
R
|
|
Attached Residential Developments
|
R
|
|
|
|
|
|
|
|
|
|
|
|
R
|
R
|
|
Commercial Developments >100,000 ft2
|
|
|
R
|
R
|
R
|
R
|
|
|
|
|
|
R
|
R
|
|
|
Automotive Service Facilities
|
|
|
R
|
R
|
R
|
|
R
|
|
|
R
|
|
R
|
R
|
|
|
Retail Gasoline Outlets
|
|
|
R
|
R
|
R
|
|
R
|
|
|
R
|
|
R
|
R
|
|
|
Restaurants
|
|
|
R
|
|
|
|
R
|
|
|
|
|
R
|
R
|
|
|
Hillside Developments
|
R
|
|
|
|
|
|
|
|
|
|
R
|
|
|
|
|
Parking Lots
|
|
|
|
|
|
|
|
R
|
|
|
|
|
R
|
|
|
Streets, Highways and Freeways
|
|
|
|
|
|
|
|
|
R
|
|
|
|
|
|
|
Notes:
|
|---|
|
R = Required to minimize pollutants of concern by selecting
appropriate Site Design and Source Control BMPs.
|
|
Table adapted from the city of Carpinteria's Water Quality Protection
Ordinance.
|
|
Table 3. Treatment Control BMP Efficiency for Pollutants of
Concern(1)
| |||||||
|---|---|---|---|---|---|---|---|
|
Efficiency of Treatment Control BMP categories for removal of
pollutants of concern include, but are not limited to:
| |||||||
|
Pollutants of Concern
|
Biofilters
|
Detention Basins
|
Infiltra-tion Basins(2)
|
Wet Ponds or Wetlands
|
Drainage Inserts
|
Filtration
|
Hydro-dynamic Separator Systems(3)
|
|
Sediment
|
M
|
H
|
H
|
H
|
L
|
H
|
M
|
|
Nutrients
|
L
|
M
|
M
|
M
|
L
|
M
|
L
|
|
Heavy Metals
|
M
|
M
|
M
|
H
|
L
|
H
|
L
|
|
Organic Compounds
|
U
|
U
|
U
|
U
|
L
|
M
|
L
|
|
Trash and Debris
|
L
|
H
|
U
|
U
|
M
|
H
|
M
|
|
Oxygen Demanding Substances
|
L
|
M
|
M
|
M
|
L
|
M
|
L
|
|
Bacteria
|
U
|
U
|
H
|
U
|
L
|
M
|
L
|
|
Oil and Grease
|
M
|
M
|
U
|
U
|
L
|
H
|
L
|
|
Pesticides
|
U
|
U
|
U
|
U
|
L
|
U
|
L
|
|
Notes:
| |
|---|---|
|
L = Low removal efficiency for this pollutant
| |
|
M = Medium removal efficiency for this pollutant
| |
|
H = High removal efficiency for this pollutant
| |
|
U = Unknown removal efficiency for this pollutant
| |
|
(1)
|
The County is encouraged to periodically assess the performance
characteristics of these BMPs to update this table.
|
|
(2)
|
Includes trenches and permeable pavement
|
|
(3)
|
Also known as hydrodynamic devices and baffle boxes
|
|
Sources: Guidance Specifying Management Measures for Sources
of Nonpoint Pollution in Coastal Waters (1993), National Stormwater
Best Management Practices Database (2001), and Guide for BMP Selection
in Urban Developed Areas (2001)
| |
|
Table adapted from the city of Carpinteria's Water Quality Protection
Ordinance.
| |
