Transcript Slide 1
Update on the Stormwater
Permitting Program
Megan Moir
Water Quality Division
Stormwater Permit Programs
Operational
Construction
Multi-Sector
Impervious Surface
Disturbed Soil
“Industrial” facilities
(a.k.a. State Stormwater
Permits, 9015, INDS)
(a.k.a. CGP, 9001, 9020,
INDC)
(a.k.a. industrial permit
MSGP, 9003)
MS4
“Big picture” permit for
concentrated
population centers
State Stormwater Permit
Jurisdictional Thresholds
Thresholds are based on area of impervious surface
Impervious = man made surfaces, including, but not limited to, paved and
unpaved roads, parking areas, roofs, driveways and walkways from which
precipitation runs off rather than infiltrates.
A State Stormwater Discharge Permit is required for projects which involve:
New impervious ≥ 1 acre;
Redevelopment of existing impervious ≥ 1 acre.
Expansions with ≥ 1 acre total resulting impervious surface (existing/redevloped
+ new), unless qualify for exemption
expansion < 5000 sf and
cumulative expansions since 7/4/2005 < 5000 sf
Thresholds are applied to the common plan of development, not individual
phases!!!
State Stormwater Discharge Permits
Do I need to obtain a State Stormwater Discharge Permit?
Permitting Flow Chart for Stormwater Discharges from Impervious Surfaces to Waters not Impaired by Stormwater
Are you constructing new impervious or redeveloping existing impervious surfaces? If you are doing both, examine jurisdiction for each type.
New Impervious Surface
Redevelopment of Existing
Impervious Surface
Are you constructing > 5000 s.f of impervious?
yes
Does the surface being redeveloped have an existing, valid stormwater permit?
no
Are you constructing ≥ 1 acre
of new impervious?
no
Has there been any construction of
impervious since 7/4/2005?
Are you redeveloping ≥ 1 acre?
yes
yes
no
yes
no
Will the amount you
are constructing plus
what has been built
since 7/4/2005
exceed 5000 s.f.?
no
no
No permit necessary
yes
Is there any existing impervious in the
project or on some related parcel (see
“total resulting”)?
yes
Must obtain a 9015 permit;
must reduce impervious
surface by 20% of area you
are redeveloping or provide
treatment for 20% of the
WQv from the redeveloped
area. *
no
No additional permit is
necessary, but no matter
how much you are
redeveloping, you must
provide the same or better
level of treatment that was
in the previous permit.
Please submit plans of
redevelopment to be
included in previous permit
file. *
*These areas still count towards your total resulting
impervious when dealing with impervious expansions!
yes
Is the total resulting (new + existing/redeveloped)
impervious surface ≥ 1 acre?
yes
You must obtain
coverage for the new
surfaces under a State
Discharge permit by
demonstrating
compliance with the 2002
VT Stormwater
Management Manual.
You must obtain coverage under a State
Discharge Permit for these new surfaces by
demonstrating compliance with the 2002 VT
Stormwater Management Manual; existing
surfaces that were previously permitted must
still receive the same treatment as in their
original permit. Changes to previously
permitted existing surfaces should be
submitted for review.
no
No permit necessary for new
surfaces; existing surfaces that
were previously permitted must still
receive the same treatment as in
their original permit. Changes
should be submitted for review.
Permitting thresholds are the same for
discharges from impervious surfaces to
waters impaired by stormwater. However, the
process of obtaining a permit is more
complicated. Projects in impaired watersheds
should refer to Chapter 22 and/or contact the
Stormwater Section.
New impervious ≥ 1 acre
1 ac
impervious
Undeveloped Land
Permit REQUIRED!
Remember, the determination must take into account all impervious in
common plan of development
Phased development must be looked at as a whole
State Stormwater Discharge Permits
Redevelopment ≥ 1 acre of existing impervious
"Redeveloped impervious": the reconstruction of an impervious surface where an impervious surface currently exists,
when such reconstruction involves substantial site grading, substantial subsurface excavation, or modification of existing
stormwater conveyance. Redevelopment does not mean management activities on impervious surfaces, including any
crack sealing, patching, cold-planing, resurfacing, paving a gravel road, reclaiming, or grading treatments used to
maintain pavement, bridges and unpaved roads. Redevelopment does not include expansions.
0.75 ac impervious in
footprint of original
impervious
Permit NOT required!
Permit REQUIRED!
1.0 ac impervious in
footprint of original
impervious
State Stormwater Discharge Permits
But obtaining permit is not as
involved – only have to treat 20%
of the Water Quality Volume or
remove an amount of existing
impervious equivalent to 20% of
the redeveloped area.
Expansions: “Total Resulting Impervious”
For purposes of determining whether or not an expansion of existing
impervious will require a Stormwater discharge permit, the following apply:
Existing impervious, and total resulting impervious shall include all impervious area within
the parcel on which the subject activity is taking place, and the impervious area on other
parcels linked by a common plan of development. A common plan of development includes
large projects, and subdivisions, the operation or creation of which required or requires state
or local permits related to either the regulation of land use or discharge to state waters.
State Stormwater Discharge Permits
Expansions: “Total Resulting Impervious”
For example, determinations must examine the existing impervious on all parcels that
are under the jurisdiction of landuse permits such as an Act 250 permit, parcels that
share common infrastructure (wastewater, roads, water supply etc), or parcels that
are in some other way part of a discernible common plan of development.
i.e. someone subdivides their property into two lots, one of which contained a house and
driveway, and then later subdivided the second lot into multiple lots that were going to be
sold for home construction.
State Stormwater Discharge Permits
Expansions: “Total Resulting Impervious”
One would need to consider both the new impervious as well the existing
impervious on the other parcel that was part of the Act 250 process. If not
Act 250 permit was involved, the common plan of development might be
indicated by a shared private road serving all homes including the existing
home, or a shared water/wastewater system.
The new impervious is considered an expansion to the original impervious on
the original lot, and the existing impervious must be counted as part of the
“total resulting impervious”.
New impervious = 0.95 acres
Existing impervious = 0.10 acres
Total resulting = 1.05 acres
State Stormwater Discharge Permits
Thus a permit is required for the
expansion!
No treatment is required for the
existing impervious.
Expansions: “Total Resulting Impervious”
For purposes of determining whether or not an expansion of existing
impervious will require a Stormwater discharge permit, the following apply:
Existing impervious, and total resulting impervious shall include all impervious area within
the parcel on which the subject activity is taking place, and the impervious area on other
parcels linked by a common plan of development. A common plan of development includes
large projects, and subdivisions, the operation or creation of which required or requires state
or local permits related to either the regulation of land use or discharge to state waters.
For highway/linear projects, the total resulting impervious shall include all impervious
surface with the project limits.
e.g.
expansion
project limits
State Stormwater Discharge Permits
STORMWATER IMPAIRED WATERSHEDS
Allen Brook
Englesby Brook
Munroe Brook
Bartlett Brook
Indian Brook
Potash Brook
Centennial Brook
Morehouse Brook
Sunderland Brook
Rice Brook
Clay Brook
Moon Brook
Roaring Brook
East Branch of Roaring Brook
N. Branch of Deerfield
Jurisdictional thresholds are the same, but sediment load calculations are
required in addition to meeting 2002 VSWMM - see Chapter 22 of the
Stormwater Rule for more information
State Stormwater Discharge Permits
Overview of the 2002 Vermont Stormwater Management Manuals (VSWMM)
Volume
I – SW Treatment Standards
Unified Sizing Criteria
Water Quality
Channel Protection
Groundwater Recharge
Overbank Flood Protection
Extreme Flood Protection
Pre-Approved STP Designs
Required Design Elements
Design Guidance
Cold Climate Required Elements
and Design Advice
Site Design Credits
Now in our 5th printing!
State Stormwater Discharge Permits
Overview of the 2002 Vermont Stormwater Management Manuals (VSWMM)
Volume
II – Technical Guidance
Site Design and Landscaping
Selecting the most effective stormwater treatment
system
Landscaping Guidance and Plant Lists
STP Construction Specs
Construction specifications for infiltration, sand filters,
bioretention and open channels
Design Examples
5 complete design examples
Assorted Design Tools
Miscellaneous Technical References
State Stormwater Discharge Permits
Water Quality Treatment
Goal: Capture and treat 90% of the annual runoff producing events
generated by the site
Treat = use an approved structural (i.e. pond, filter, infiltration basin) or nonstructural (i.e. disconnection) practice which has been shown to remove 80%
TSS and 40% TP
Provide treatment for the entire site’s runoff up to the 0.9” storm
Water Quality Volume (WQv) = (0.9*Rv*A)/12 where:
A = site area (impervious + disturbed pervious)
Rv = 0.05+0.009I (I = % impervious)
Minimum WQv = 0.2 watershed inches
State Stormwater Discharge Permits
Amount of impervious area is
largest contributor
WQv formula simplifies to:
0.00375A + 0.0675(IA), where
IA = impervious area (acres)
Water Quality Treatment
Typical STPs
Ponds
Wetlands
Infiltration Systems
Filters (including Bioretention)
Grass Swales (specially designed)
Treatment practices included in Volume I of the 2002 SWMM are
identified as providing 80% removal of TSS and 40% removal of TP
State Stormwater Discharge Permits
Groundwater Recharge
Goal: To preserve existing water table elevations by maintaining the average annual
recharge rate for the site
Replicate pre-development recharge through a standard based upon the annual
average recharge of the site’s existing Hydrologic Soil Groups (i.e. no recharge
required for D soils)
Recharge Volume [Watershed Inches]
0.45
0.40
0.35
0.30
A Soils
0.25
0.20
B Soils
0.15
0.10
C Soils
0.05
0.00
0
D Soils
10
20
30
40
50
60
Site Imperviousness [%]
70
80
90
100
Table 2.2 in the VSWMM manual lists acceptable stormwater treatment practices for
recharge
State Stormwater Discharge Permits
Site Design Credits
Site Design Credits are often used to meet Water Quality and
Recharge Requirements
Currently Approved Site Design Credits
Conservation Areas
Disconnection
Slope requirements
Stream Buffers
Grass Channels
Environmentally Sensitive Rural Development
Slope and land-use
requirements
Pay careful attention to each of the criteria that must be met in
order to qualify for these credits
Slope
Land-use/density
Contributing length : treatment length, etc.
State Stormwater Discharge Permits
Channel Protection
Goal: Protect downstream receiving
channels from degradation
Provide 12 or 24 hour detention of site
runoff from the 1 year – 24 hour storm
(approximately 2.1 - 2.3 inches in Vermont)
12 hour detention for cold water receiving
streams
24 hour detention for warm water receiving
streams or wetlands
Waived for sites
With < 1 acre of expansion;
With < 2 cfs of discharge; or
Discharging to waterbody with > 10 sq. mi.
drainage area
State Stormwater Discharge Permits
Channel Protection: CPv
Qpost –higher
Q and larger Vr
Qpre
Q
Qcrt
Qpost-controlled
Q
Qcrt
Qpre
Time
Time
Providing peak discharge control DOES NOT meet CPv
The goal is to release runoff gradually so that critical erosive flows/velocities
(Qcrt) will seldom be exceeded downstream.
The extended detention is used as a surrogate for the more involved Distributed
Runoff Control method (Appendix D9, 20 pgs long), which is the more involved
method of determining the appropriate channel protection release rate.
Overbank Flood Protection (Qp10)
Goal: Protection of downstream infrastructure from an increase in the
frequency and magnitude of overbank flooding
Provide storage to control the peak discharge of the post developed runoff
volume from the 10-year, 24-hour storm (ranges from 3.1 to 4.0 inches in
Vermont ) by releasing at the pre-development runoff rate.
Qp10 may be waived for projects where:
Discharges to receiving waters with drainage areas greater than 10 sq. miles; or
Site is smaller than 5 acres AND channel has capacity to convey the post
development discharge downstream to the point of the 10% rule
State Stormwater Discharge Permits
Extreme Flood Protection (Qp100)
Goal: Prevent flood damage from infrequent but very large storm events,
maintain the boundaries of the predevelopment 100-year floodplain, and
protect the physical integrity of a stormwater management practice itself
Provide storage to control the peak discharge rate of the post development
runoff volume from the 100-year, 24-hour storm (ranges from 5.0 – 6.8
inches in Vermont) by releasing at the predevelopment runoff rate.
Qp100 may be waived for projects where:
Discharges to receiving waters with drainage areas greater than 10 sq. miles; or
Impervious acreage < 10 acres; or
A downstream analysis is conducted that indicates extreme flood control is not
necessary
State Stormwater Discharge Permits
Demonstrating Compliance
Design standards
Water Quality
Pre-treatment: largely to reduce maintenance frequency
Treatment: Standards linked to unit processes of different types of
practices, e.g.:
–
–
–
–
–
Ponds: settling/sedimentation; biologic processes
Infiltration
Grass Channels: sedimentation
Filters: physical filtration and/or sorption depending on media
NEED TO KNOW HOW EACH PRACTICE WORKS TO DESIGN EFFECTIVE
TREATMENT
Water Quantity
Runoff models with detention components.
Importance of Models
Construction Stormwater Permitting
in Vermont - Overview
Since 2002, 5 acre+ projects have required permits
New General Permit issued September 13, 2006 for 1 acre+
disturbance projects, replaces original permit
Required by Federal Clean Water Act and National Pollutant Discharge
Elimination System Phase II (NPDES)
Includes smaller projects part of larger common plan of development
Construction Stormwater Permitting
in Vermont - Overview
Winter Construction
Winter Oct 15-Apr 15
Requires notification of planned work, implementing standard winter
EPSC measures, including:
Daily mulching (unless work is in a self contained trench and/or no
precipitation is forecast for the next 24 hours)
Double the mulching rate
Construction Stormwater Discharge Permits
Construction Stormwater Permitting
in Vermont-Filing Applications
CGP Eligibility determined by Risk of Sediment Discharge and
receiving water sensitivity
Type of Waters (impaired, Outstanding Resource)
Extent of Disturbance (2 acres, 5 acres, 7 acres)
Duration of Disturbance (7, 14, or 21 days)
Slopes and Soils
Presence/absence of Vegetated Buffers
Work within resource buffer
Construction Stormwater Discharge Permits
Construction Stormwater Permitting
in Vermont-Filing Applications
3 Permitting Possibilities:
1. Low Risk
2. Moderate Risk
3. Individual Permit
Construction Stormwater Discharge Permits
Eligible for General Permit
Construction Stormwater Permitting
in Vermont – Filing Applications
Risk Evaluation
Series of Yes/ No, Q/A
Focused on Erosion Prevention
Encourages voluntary phasing,
prompt stabilization, use of
vegetated buffers
If project is not automatically low
risk, then must do detailed
evaluation comparing risk factors
and risk mitigation factors.
Construction Stormwater Discharge Permits
Construction Stormwater Permitting
in Vermont – Filing Applications
Basic Risk Evaluation
Project is automatically Low Risk if meet all of the following:
1.
2.
3.
4.
< 2 acres
50 ft vegetated buffer
14 days maximum disturbance in any area before temporary or
permanent stabilization
Not discharging to special class of water
Construction Stormwater Discharge Permits
Construction Stormwater Permitting
in Vermont – Filing Applications
Low Risk Projects
Submit Notice of Intent
Agree to implement Low Risk
Guide
~10 days to authorization
Valid for 2 years
Construction Stormwater Discharge Permits
Construction Stormwater Permitting
in Vermont – Filing Applications
Low Risk Handbook
Common practices
Basic use
Suited to low risk construction
Construction Stormwater Discharge Permits
Construction Stormwater Permitting
in Vermont – Filing Applications
Once Authorized
Receives Notice of Authorization
Lists all voluntary limits
Posted at site for public and
inspector reference, remind
permittee
Construction Stormwater Discharge Permits
Construction Stormwater Permitting
in Vermont – Filing Applications
Moderate Risk Projects
Submit Notice of Intent
Site specific EPSC plan
with EPSC Summary
Forms
Construction Stormwater Discharge Permits
Construction Stormwater Permitting
in Vermont – Filing Applications
Once Authorized
Receives Notice of Authorization
for posting
Receives OSPC Handbook
Receives Field Guide
Construction Stormwater Discharge Permits
Construction Stormwater Permitting
-Field Implementation
On-Site Plan Coordinator in charge of compliance
Weekly & Post-Runoff Inspections
Discharge Reports
Track Amendments
On-Site Plan Coordinator Handbook
Construction Stormwater Discharge Permits
Construction Stormwater Permitting
in Vermont – Filing Applications
Projects Requiring
Individual Permit
Submit Application
Site specific EPSC plan
Usually WQ monitoring,
EPSC specialist oversight
Construction Stormwater Discharge Permits
Erosion Prevention and Sediment Control Plan
General Approach
Minimize
disturbance
Manage runoff
Stabilize promptly
Establish
Vegetation
Construction Stormwater Discharge Permits
EPSC- Stabilization
Frequent mulching
Construction Discharge Permits
EPSC- Perimeter Control
Silt fence
Show silt fence on EPSCP sheet as it should be - ON THE CONTOUR!
Inspection and maintenance are a must!
Silt fence should NOT be used for demarcation of the limits of disturbance!
Construction Stormwater Discharge Permits
EPSC- Perimeter Control
Construction Stormwater Discharge Permits
Discharges Associated
with Industrial Activities
(3-9003)
Christy Witters
DEC Stormwater Section
www.vtwaterquality.org/stormwate
r.htm
(802) 241-3777
MSGP Outline
Purpose
Who
requires MSGP coverage
Types of MSGP coverage
No Exposure Conditional Exclusion
Notice of Intent (NOI)
Due
dates for applying
Application review procedure
MSGP Overview
Goal: Prevent pollution from industrial activities
VT MSGP signed August 18, 2006
5 year National Pollutant Discharge Elimination
System (NPDES) permit required by Federal law
Requires facilities that have industrial materials
or activities exposed to stormwater to:
Prepare a Stormwater Pollution Prevention Plan
(SWPPP)
Monitor outfalls for potential pollutants
Regulated Activities
Industrial
facilities
SIC code of the facility’s primary activity is
listed in Table D-1 of the permit
Regulated Activities
Any facility with one of the following activities on
site:
Stormwater discharges with specific effluent
limitations (Table 1-1)
Types of MSGP coverage
No
Exposure Conditional Exclusion
Certify that the facility meets the No
Exposure conditions
Permit
Coverage
Submit Notice of Intent
Prepare Stormwater Pollution Prevention
Plan (SWPPP)
Implement Best Management Practices
(BMPs)
Conduct Monitoring
No Exposure
No
Exposure
All materials and activities are protected by a
storm resistant shelter to prevent exposure
to rain, snow, snowmelt, and/or runoff
Storm resistant shelter
No Exposure
Materials
that may be stored outdoors
Above Ground
Storage Tanks not
associated with
vehicle maintenance
Adequately maintained
vehicles
Sealed drums, barrels, tanks
without operational taps or
valves; not deteriorating
Lidded dumpsters
Final products intended for
outdoor use & not deteriorating
Types of MSGP coverage
Full Application
for coverage
Notice of Intent (NOI) – application form
Prepare and implement Stormwater Pollution
Prevention Plan (SWPPP)
• Best Management Practices (BMPs)
Behavioral and Structural BMPs
Conduct stormwater monitoring
Application deadlines
Exposure – immediately
NOI
No
Existing facilities – immediately
New facilities – 90 days prior to commencing
activities
SWPPP
Existing facilities – May 15, 2007
New facilities – 90 days prior to commencing
activities
Application Review Procedure
No
Exposure
Applications checked for completeness and
approved
NOI
Applications checked for completeness
10 Day Public Comment Period
Activity authorized under the permit
SWPPP
Reviewed when they are received
Expecting most SWPPPs near May 15
deadline
Municipal Separate Stormwater
Systems
(MS4)
Eight municipalities (Burlington,
Essex, Essex Jct, Milton, Shelburne,
South Burlington, Williston and
Winooski
Three “non-traditional” (systems
owned or operated by UVM,
Burlington International Airport and
VTRANS)
MS4 Permits
MS4 6 Minimum Measures
1. Public Education and Outreach
www.smartwaterways.org
2. Public Participation and Involvement
3. Illicit Discharge and Detection Elimination
4. Construction Site Runoff Control
5. Post-construction Site Runoff Control
6. Pollution Prevention / Good Housekeeping
For questions, contact Jim Pease at VT SWMP
MS4 Permits