Update on the Stormwater Permitting Program Megan Moir

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) MS 4 “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 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 Undeveloped Land 1 ac impervious § 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. expansion e. g. 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 5 th 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. 009 I (I = % impervious) § Minimum WQv = 0. 2 watershed inches State Stormwater Discharge Permits Amount of impervious area is largest contributor WQv formula simplifies to: 0. 00375 A + 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 D 9, 20 pgs long), which is the more involved method of determining the appropriate channel protection release rate.

Overbank Flood Protection (Qp 10) § 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. § Qp 10 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 (Qp 100) § 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. § Qp 100 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 Ø Purpose Ø Who requires MSGP coverage Ø Types of MSGP coverage l l No Exposure Conditional Exclusion Notice of Intent (NOI) Ø Due dates for applying Ø Application review procedure

MSGP Overview Goal: Prevent pollution from industrial activities Ø VT MSGP signed August 18, 2006 Ø 5 year National Pollutant Discharge Elimination System (NPDES) permit required by Federal law Ø Requires facilities that have industrial materials or activities exposed to stormwater to: Ø l l Prepare a Stormwater Pollution Prevention Plan (SWPPP) Monitor outfalls for potential pollutants

Regulated Activities Ø Industrial l facilities SIC code of the facility’s primary activity is listed in Table D-1 of the permit

Regulated Activities Ø Any facility with one of the following activities on site: l Stormwater discharges with specific effluent limitations (Table 1 -1)

Types of MSGP coverage Ø No l Exposure Conditional Exclusion Certify that the facility meets the No Exposure conditions Ø Permit l l Coverage Submit Notice of Intent Prepare Stormwater Pollution Prevention Plan (SWPPP) Implement Best Management Practices (BMPs) Conduct Monitoring

No Exposure Ø No l Exposure All materials and activities are protected by a storm resistant shelter to prevent exposure to rain, snowmelt, and/or runoff Storm resistant shelter

No Exposure Ø Materials that may be stored outdoors Adequately maintained Above Ground Storage vehicles Tanks not associated with vehicle maintenance 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 Ø Full l l Application for coverage Notice of Intent (NOI) – application form Prepare and implement Stormwater Pollution Prevention Plan (SWPPP) • Best Management Practices (BMPs) l l Behavioral and Structural BMPs Conduct stormwater monitoring

Application deadlines Ø No Exposure – immediately Ø NOI l l Existing facilities – immediately New facilities – 90 days prior to commencing activities Ø SWPPP l l Existing facilities – May 15, 2007 New facilities – 90 days prior to commencing activities

Application Review Procedure Ø No l Exposure Applications checked for completeness and approved Ø NOI l l l Applications checked for completeness 10 Day Public Comment Period Activity authorized under the permit Ø SWPPP l l Reviewed when they are received Expecting most SWPPPs near May 15 deadline

Municipal Separate Stormwater Systems (MS 4) § Eight municipalities (Burlington, Essex Jct, Milton, Shelburne, South Burlington, Williston and Winooski § Three “non-traditional” (systems owned or operated by UVM, Burlington International Airport and VTRANS) MS 4 Permits

MS 4 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 MS 4 Permits