meeting the chesapeake bay restoration requirements for...
TRANSCRIPT
Meeting the Chesapeake Bay Restoration Requirements for
Industrial Sites in MD
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Poll Question #1
How many people are watching with you today?
• Just me
• 2-5 people
• 6-10 people
• > 10 people
Poll Question #2
Are you required to submit a restoration plan for your site?
• Yes
• No
• Yes, but I already did
Speaker Info
Paul Hlavinka, Maryland Department of the Environment, [email protected]
Marjorie Mewbourn, Maryland Department of the Environment, [email protected]
Ted Scott, Stormwater Maintenance & Consulting, [email protected]
Cecilia Lane, Chesapeake Stormwater Network, [email protected]
Today’s Agenda
• The Basics of the Chesapeake Bay Restoration Requirements
• Control Measures for Nutrient Reduction
• Restoration Overview w/ MDE
• Q&A
• Webcast Resources
Chesapeake Bay Restoration Requirements
Required to comply with if you meet ALL of these criteria:
• Your facility is within the Chesapeake Bay Watershed
• Your facility is 5 acres or greater in size
• Any portion of your facility is located within a Phase I or Phase II municipal separate storm sewer system (MS4) jurisdiction
• Your facility is not owned by or leased from an entity that is permitted as an MS4
Chesapeake Bay Specific NOI Requirements
THEN you must provide:
• Total impervious surface area (square feet)
• Untreated impervious surface area (in square feet)
• Impervious surface area subject to 20% restoration requirement (in acres).
Calculating the Impervious Area Subject to 20% Restoration
Defined as the total area of untreated impervious surfaces that existed at your facility prior to January 1, 2006
Is the baseline for determining the applicable amount of control measures needed at your facility
Calculating Your Baseline Load
• Based on the impervious cover of your site
• Focused mainly on Nitrogen for cleaning up the Bay
Pollutant Loads by Land Cover
Parameter Urban Impervious (lbs/ac/yr)
Urban Pervious (lbs/ac/yr)
Forest (lbs/ac/yr)
TN 10.85 9.43 3.16
TP 2.04 0.57 0.13
TSS (tons) 0.46 0.07 0.03
Impervious surfaces are surfaces that do not allow stormwater to infiltrate into the ground
Includes: driveways, roads, parking lots, buildings, water resistant material covers, sidewalks, paved decks, tanks etc.
Calculating the Impervious Area Subject to 20% Restoration
Control Measures for Nutrient Reduction
Any treatment of impervious surfaces added since January 1, 2006 can be counted towards meeting the 20% restoration requirement
Select, design, install and implement restoration of 20% impervious surface area or equivalent control measures for the reduction of nutrients by December 31, 2018
You must implement at your facility unless infeasible, and only then by working through your local jurisdiction to implement project(s) offsite.
For 02-SW permittees: control measures must be implemented within 5 years of the permit effective date
All other permittees: 4 years from the date you file an NOI.
No marketable credits.
Restoration of impervious surfaces is defined as the treatment of untreated impervious surfaces with structural or non-structural stormwater best management practices (BMPs) found in the MD Design Manual based upon designs that treat the volume from one inch of rainfall.
Restoration Options
• Design Manual or Proprietary Practices
• Accounting Guidance Practices
• Equivalent control measures
• Off-Site
Meadowbrook Parking Lot
Naturalization Project
Practices found in the Design Manual
Design Manual provides engineering guidance for when to “infiltrate, reuse, or otherwise manage stormwater” e.g.,
• Permeable Pavements
• Reinforced Turf
• Rainwater Harvesting
• Infiltration Berms
• Green Roofs
• Etc.
• Outlines “equivalent” controls which can be considered by industrial facilities
• Addresses situations where site constraints do not allow for capture of the full 1” (WQv) treatment and demonstrates how the impervious cover area can be pro-rated based on the volume of treatment
Accounting Guidance Practices
Retrofitting
Street Sweeping
Catch Basin Cleanout
Impervious Surface Elimination
Tree Planting and Reforestation
Regenerative Step Pool Storm Conveyance
Stream Restoration
Shoreline Management
Nutrient Management
Septic Tank Management
Accounting guidance practices can include:
Equivalent Control Measures
• New controls required by this permit for erosion and sediment control, or for reduced use of fertilizer.
• New controls to achieve the benchmarks for nitrogen required by this permit, if benchmarks are applicable for your facility.
• Reducing an existing TN load allocation under an individual NPDES permit.
Other equivalent control measures are those which achieve reduction of 5.4 lbs total nitrogen (TN)/year = 1 acre restoration. Can include:
ESC
• Applies to “enhanced ESC” practices
• Includes Level 2 practices
• Only 25% reduction of TN = requires twice as many to meet the N reductions
More Information:
• Guidance on MDE’s website
• Recently approved Expert Panel report
• Archived webcast on recommendations
Level 2 ESC Practices
Protect Natural Resources
Do #1 and add buffers to LOD to prevent discharge to natural area
Minimize Disturbance
Construction phasing required for largest projects (e.g., 25 + acres)
Stabilize Soils Stabilize w/in 7 -14 days
Internal Drainage
Swales/diversions with check-dams and erosion control blankets
Perimeter Controls
Reinforced silt fence and berms/diversions
Sediment Traps and Basins
Sediment basins that meet the 1.0" (3,600 cu.ft/ac) standard, with permanent pools and/or dewatering control devices (e.g., skimmers)
Inspections Every 1 to 3 weeks From the 2014 ESC Expert Panel Report
Accounting guidance document describes…
• How to establish baseline conditions for impervious are restoration
• How to apply impervious cover restoration credits for BMP implementation
• How to apply pollutant removal credits for BMP implementation
• Expands the list of traditional water quality practices to offer “alternative BMPs” that can be used for restoration
Stormwater Retrofits
Stormwater retrofits are stormwater management practices in locations where stormwater controls did not previously exist or were ineffective
Two main types:
1. Retrofits of existing BMPs
a) BMP Conversions
b) BMP Enhancements
c) BMP Restoration
2. New retrofits to manage stormwater
EXISTING RETROFITS
BMP CONVERSION
DRY POND
CONSTRUCTED WETLAND
BMP CONVERSIONS Adding Bioretention/Filtering to Ponds
EXISTING RETROFITS
BMP ENHANCEMENT
Increase in hydraulic retention time
EXISTING RETROFITS
BMP RESTORATION
Dredging an underperforming pond to restore full performance
New Retrofits
Providing stormwater management in previously untreated areas
• Near existing stormwater outfalls
• Within the existing conveyance system
• Adjacent to large parking lots or other areas of impervious cover
Calculating Removal from Retrofits
• Standard design is based on treatment of the WQv
• Credits are pro-rated on the retrofits ability to meet the WQv
• Extra pollutant credit for extra treatment !!
Need to know: – Runoff depth treated per impervious cover
(accounting guidance document)
– Classification of BMP
Classification of BMPs Runoff Reduction Practices
(RR)
Stormwater Treatment
Practices (ST)
Bioretention Constructed Wetlands
Dry Swale Filtering Practices
Infiltration Proprietary Practices
Permeable Pavement Wet Swale
Green Roof Wet Ponds
All practices sorted into 2 categories: Runoff Reduction (RR) &
Stormwater Treatment (ST)
Achieve at least 25% reduction of annual runoff volume
Traditional Practices
• An infiltration basin that accepts runoff from an industrial site has failed. The site owner converts it to a wet swale (considered a ST practice)
• The runoff depth per impervious cover (Q) of the new facility is 1.0 inches
Design Example: BMP Conversion
Failed infiltration basin to Wet Swale
TP TN TSS
55% 35% 70%
Pollutant Removal Efficiencies of the practice
Design Example: BMP Conversion
Removal Rates for ESD/RR and ST Practices
Stormwater Retrofits
Calculating the Impervious Area Equivalent for stormwater retrofits:
• 1.o” of treatment = 1 acre of impervious area treated
• 0.1 acres for every 0.4” treated above 1”
• Incentive for treating > 1”
Street Sweeping
• Practice exclusively implemented on impervious area
• Uses mechanical or vacuum-assisted sweeper trucks
• Streets/areas must be swept 2x month
• Materials collected must be disposed of properly
Street Sweeping
• Two methods for calculating reductions:
– Mass Loading Approach
– Qualifying Street Lanes Method
• Mechanical sweepers get lower reductions than vacuum-assisted or regenerative air sweepers
• Street sweeping is an annual practice that will be updated regularly
• Must report tons of debris removed (method 1) or number of acres swept (method 2) – outlined in accounting guidance document
Mass Loading Approach
Mass of collection measured (tons) at point of disposal and converted to pounds of pollutants:
1. Determine “dry mass” of material: total lbs of material * 70%
2. Calculate pollutant reductions by:
• Lbs of TN = 0.0025 lbs of dry weight solids
• Lbs of TP = 0.001 lbs of dry weight solids
3. Compute TSS reduction credit by multiplying the annual mass of dry weight by a factor of 0.3
Example MD Community wants to take credit for their street
sweeping program. They have a regenerative street sweeper with a hopper capacity of 2 tons. On average they have collected a wet mass of 1.5 tons over the course of the year.
Mass Loading Approach
1. Convert tons of wet mass into lbs and convert to dry weight:
1.5*2000 = 3000 lbs of street solids (wet)
3000*0.7 = 2100 lbs of street solids (dry)
2. Derive nutrient reductions:
2100*0.0025 = 5.25 lbs of TN
2100 * 0.001 = 2.1 lbs of TP
3. Compute TSS Reduction:
2100*0.3 = 630 lbs of TSS
Street Lane Approach
Facility reports number of lane miles swept during the course of a year. Use formula to convert lane miles swept into acres:
(miles swept)*(5,280 ft/mile)*(land width ft)
43,560 ft2/acre
Total acres swept is multiplied by annual nutrient and sediment load for impervious surfaces to get the baseline load.
TN TP TSS (tons)
Urban Impervious (lbs/ac/yr)
10.85
2.04
0.46
The baseline load is multiplied by the pollutant removal efficiencies for the type of sweeper to determine the load reduction.
• Mechanical sweepers get lower reductions than vacuum-assisted or
regenerative air sweepers
• Street sweeping is an annual practice that will be updated regularly
• Must report tons of debris removed (method 1) or number of acres swept (method 2) – outlined in accounting guidance document
Street Lane Approach
Street Sweeping Pollutant Removal Efficiencies
Technology TN TP TSS
Mechanical .04 .04 .10
Regenerative/Vacuum .05 .06 .25
Over the past year, a municipality has swept their streets every other week (26 times) with a regenerative street sweeper.
This equates to community swept 25 lane miles which included both sides of the street.
This is converted to an area: Both sides of the street were swept, so an average width of 20 feet could be used.
Using the equation in the guidance document, the facility calculated the total acres swept to be in the past year = 60.61 acres.
Example: Street Lane Approach
Multiplying the impervious acreage swept (60.61 acres) by the pre-sweeping annual pollutant load, the community was able to determine their baseline load
The facility then multiplied the baseline load by the
Regenerative Technology factors to get load reductions based on their program:
Calculating the Baseline Load
Pollutant Acres Swept
Annual Pollutant Load (lbs/ac/yr)
Baseline Load (lbs/yr)
Regenerative Technology Factor
Load Reduction
Phosphorus 60.61 2.04 123.64 .06 7.42
Nitrogen 60.61 10.85 657.62 .05 32.89
Example: Street Lane Approach
Equates to treatment of 4.33 acres of impervious cover credit
Street Sweeping
• Currently the subject of a CBP expert panel
• Rates to change based on the outcome of the panel
• Panel recommendations due out in the first quarter of 2015
Delta Values
Conversion from (lbs/ac/yr)
TN (lbs/ac/yr)
TP (lbs/ac/yr)
TSS (tons/ac/yr)
Urban Impervious 10.85 2.04 0.46
Forest 3.16 0.13 0.03
Load Reduction 7.69 1.91 0.43
Urban Pervious 9.43 0.57 0.07
Forest 3.16 0.13 0.03
Load Reduction 6.27 0.44 0.04
Street Sweeping Example Calculating the Equivalent Impervious Cover
Method for Converting Street Sweeping Acres to Equivalent Impervious Cover Treated (acres)
Pollutant Acres Swept
Load Reduction (lbs/acre/
year)
Total Load Reduced
Delta (lbs/acre/
year)
Equivalent Impervious
Cover (acres)
Total N 60.61 0.43 26.06 7.69 3.39
Total P 60.61 0.08 4.85 1.91 2.54
Sediment (tons)
60.61 0.05 3.03 0.43 7.05
Equates to treatment of 4.25 acres of impervious cover credit
Converting Acres Swept vs. Impervious Area Treated
• The equivalent impervious cover treated is calculated by multiplying the area swept by a conversion factor based on the type of technology used.
• Examples of reductions for various drainage areas listed below
Method for Converting Acres Swept to Equivalent Impervious Cover Treated (acres) Acres Swept
Mechanical Sweeper
Conversion Factor
Equivalent IC Acres
Treated
Regenerative Sweeper
Conversion Factor
Equivalent IC Acres
Treated
2 0.07 0.14 0.13 0.26 50 0.07 3.5 0.13 6.5
100 0.07 7.0 0.13 13
Catch Basin Cleaning/ Storm Drain Vacuuming
• Involves performing routing cleanouts of targeted infrastructure with high sediment accumulation rates
• An annual BMP which must be updated yearly
• Pollutant reductions are calculated using the mass loading approach outlined in the guidance document
• Multiply tons of dry material collected by 0.40 to calculate the IAE
Impervious Surface Elimination
Removal of impervious cover and replace with vegetation
Photo credit: Blue Water Baltimore
Impervious Surface Elimination
Two types:
1. Impervious to Pervious: Removal of pavement and providing vegetative cover for 95% of area
2. Impervious to Forest: Survival rate of 100 trees/acre or greater, At least 50% of trees 2” diameter or greater at 4.5’ above ground level (same qualifying conditions as reforestation)
Practice TN TP TSS
Equivalent IC Acres
Treated
Impervious to Pervious 13% 72% 84% 0.75 Impervious to Forest 71% 94% 93% 1.00
Tree Planting and Reforestation
• Survival rate of 100 trees/acre or greater
• At least 50% of trees 2” diameter or greater at 4.5’ above ground level
• Aggregate of smaller sites is okay
• Credits are determined as land cover conversion based on the following efficiencies:
Reforestation of previously grassed areas
Delta Values
Conversion from (lbs/ac/yr)
TN (lbs/ac/yr)
TP (lbs/ac/yr)
TSS (tons/ac/yr)
Urban Pervious 9.43 0.57 0.07
Forest 3.16 0.13 0.03
Load Reduction 6.27 0.44 0.04
Efficiency 66% 77% 57%
Urban Impervious 10.85 2.04 0.46
Forest 3.16 0.13 0.03
Load Reduction 7.69 1.91 0.43
Efficiency 71% 94% 93%
For mimicking forest conditions
Pollutant for pervious urban is used
Reforestation Example
Municipal works yard reforests 10 acres of turf (pervious land) in a subwatershed
Method for Converting Acres Reforested to Equivalent Impervious Cover Treated (acres)
Pollutant
Acres Converted
from Turf to Forest
Load Reduction (lbs/acre/
year)
Total Load Reduced
Delta (lbs/acre/
year) 3
Equivalent Impervious
Cover (acres)
Total N 10 6.27 62.7 7.69 8.15
Total P 10 0.44 4.4 1.91 2.30
Sediment (tons)
10 0.04 0.40 0.43 0.93
Equates to treatment of 3.8 acres of impervious cover credit
Regenerative Step Pool Storm Conveyance
Open channel conveyance structures that convert, through attenuation ponds and a sand seepage filter, surface storm flow to shallow groundwater flow
Pollutant reductions calculated through retrofit removal adjustor curves or proportion of the full WQv treated
Severn Riverkeeper Carriage Hills Stream Restoration Project
Stabilization or repair of localized areas of erosion below a storm drain outfall
• Impervious area equivalent is 0.01
• Maximum credit is 2 acres per project
Outfall Stabilization
Shoreline Management
• Use of nonstructural practices or living shorelines to stabilize shoreline in MD
• Include: tidal marsh creation, beach nourishment, stone revetments, breakwaters and groins
• Credit per linear foot of practice implementation
Poplar Point Residential BMP Project
Shoreline Management
• Baltimore County rate is “old” rate
• Alternative rate is under review by CBP – due out early 2015
• Once approved, must use the newer CBP rate
Practice TN
(lbs/linear ft) TP
(lbs/linear ft) TSS
(lbs/linear ft)
Equivalent IC Acres
Treated
Baltimore County 0.16 0.11 451 0.04
CBP Rate 0.075 0.068 137 0.04
Nutrient Management
• Maryland passed state law that regulates use of urban nutrient management
• As a result, all to receive credit
• Can received additional credit if do a UNM plan for your site AND can show measureable differences in application/purchase of fertilizer
Septic Tank Management
Includes:
• Pumping: is considered an annual BMP and must be updated annually
• Denitrification: considered to be permanent
• Direct connections to WWTP: considered to be permanent
• Credits apply to ICE only
• Multiply number of facilities being managed this way to get number of impervious acres credited e.g., 10 septics connected to WWTP equates to 3.9 acres of impervious cover treated
Practice Equivalent IC Acres
Treated
Pumping 0.03 Denitrification 0.26 Connection to WWTP 0.39
Website Resources
http://www.mde.state.md.us/programs/Permits/WaterManagementPermits/WaterDischargePermitApplications/Pages/ChesapeakeBayRestorationGuidance.aspx
Operator Example
• Privately owned 12.5 Acre scrap yard in Baltimore City
• In Chesapeake Bay, in Baltimore City (an MS4), over 5 acres, not owned by MS4.
• Scrap recycling facility (Sector N1) except source separate recycling, therefore is subject to benchmarking.
• Discharge is to Patapsco River, impaired for Biological, Metals, Nutrients, PCBs, Pesticides, and Sediments.
Opportunities for Restoration
Property 12.5 acres, w / 5.25 acres either road, roof, or paved untreated spaces.
20% = 1 acre restoration
Restoration Options: • Bioretention at office • Cistern at shop • Adding trees • Better erosion & sedimentation
control • Street sweeping
FAQ
Q: In Appendix E of the permit it states,
Industrial facilities may not consider section 9 of that document “Alternative BMPs for Consideration”, which were alternative BMPs recommended by Maryland's NPDES municipalities for further examination by the Department. Can you explain?
A: All practices included in the Accounting Guidance document can be considered.
FAQ
Q: We’ve been using the 2011 version of the accounting guidance document to account for the pollutant loading coming off our site and the reductions from our restoration strategies but now there is a new version – gah!
A: You can use either the draft version (2011) or the new one (2014) to do your calculations – no worries!
Questions
Maryland Department of the Environment
12-SW General Permit for Stormwater Discharges Associated With Industrial Activity (Final
Determination)
Restoration Overview with
NOI Requires - Chesapeake Bay Specific
If your facility meets ALL of these criteria :
– within the Chesapeake Bay Watershed;
– is 5 acres or greater in size;
– in an urban area as specified “any portion of your facility is located
within a Phase I or Phase II municipal separate storm sewer
system (MS4) jurisdiction”; and
– is not owned by or leased from an entity that is permitted as an
MS4.
THEN you must provide:
– the total impervious surface area (square feet),
– the untreated impervious surface area (in square feet) and
– the impervious surface area subject to 20% restoration
requirement (in acres).
Restoration Options • Design Manual or Proprietary Practices
– Examples: Green Roof or Cisterns
• Accounting Guidance Practices (Draft or 2014)
– Examples: Street Sweeping or replacing pavement with green
space.
• Equivalent control measures
– Achieve reduction of 5.4 lbs total nitrogen (TN) per year is
equivalent to restoration of one acre of impervious surface area.
– New controls required for erosion and sediment control or reduced
use of fertilizer.
– New controls to achieve the benchmarks for nitrogen
– Reducing an existing TN load allocation
• Off-Site
Frequent Questions
• Owner vs Operator…who is required to
get the permit?
• Can the operator apply for No Exposure or
break down property into parcels to avoid
permitting?
• Leased property required to consider the
restoration requirements?
• Infeasible and offsite work.
SWPPP Expectations?
• Table of calculations and narratives as
required by the permit (12-SW pages 11-
12 “Nutrient Control Measure Planning
and SWPPP Documentation”).
• Identification of Restoration Activities on
the site map.
• NOI and SWPPP is in SQ Feet and Acre.
Please use correct units.
• Refer to practices in design manual etc.
Required Elements in SWPPP
Step a. Identify all impervious surfaces that are subject to this permit, and calculate
the total impervious surface area for your facility.
Step b. Identify the impervious surface area treated with existing stormwater best
management practices (BMPs) that provide the full one inch or WQv treatment.
Step c. Identify the impervious surface area partially treated by existing stormwater
best management practices (BMPs) that don’t provide the full one inch or WQv
treatment.
Step d. Subtract the treated area result in “b” above and the adjusted partially
treated area result in“c” above from the total impervious surface area result in
“a” above. The resulting value represents the untreated impervious surface
area.
Step e. Multiply the untreated impervious surface area (result in “d” above) by 20%
to calculate the impervious surface area subject to the 20% control measure
requirement. Convert this area to acres.
Step f. Determine all of your available options
as follows:
i.) restoration control measures using the
Design Manual and/or Proprietary Practices;
ii.) control measure alternatives through the
Accounting Guidance; and
iii.) equivalent control measures.
• Step g. Evaluate and then select practices from the options
(identified in “f” above) that you will implement to comply with
the control measure requirement of this permit (result in “e”
above).
• Step h. If after evaluating your potential options for nutrient
reductions, you determine it is infeasible to meet the nutrient
reduction requirements at your facility, provide your rationale
and describe your alternate plan and schedule consistent with
Part III.A.1.d for coordinating with the local jurisdiction to
implement equivalent off-site projects.
• Step i. Document your selection of BMPs and equivalent
measures, including calculations that show your approach will
achieve the nutrient reduction requirement.
• Step j. Provide a schedule and basis for all options
you selected that cannot be implemented within 30
days of registration under this permit.
• Step k. Specify appropriate routine maintenance
schedules for all new and existing BMPs. Include in
your plan a procedure for inspection and
documentation of those inspections for all structural,
nonstructural and other equivalent control measures.
• Step l. Modify the resulting plan as needed to keep
implementation on pace to meet the permit deadline.
Facility SWPPP Map Example
Other Issues?
• Approved Proprietary Practices, make sure
to include your letter from MDE in SWPPP.
• Unapproved Proprietary Practices - approval
takes time.
• Alternative BMPs or nonstructural elements
of Acct Guidance. Make sure you fully
understand the practice. Example catch
basin and street sweeping.
• Commingling from run-on and run-off.
1800 Washington Boulevard | Baltimore, MD 21230-1718 410-537-3000 | TTY Users: 1-800-735-2258
www.mde.maryland.gov
Maryland Department of the Environment
Water Management Administration Industrial and General Permits Division
410-537-3323
Marjorie Mewbourn [email protected]
Paul Hlavinka
Questions?
Webcast Resources
• Maryland Industrial Stormwater Permit (12-SW)
• Accounting for Stormwater Wasteload Allocations and Impervious Acres Treated
• Enhanced Erosion and Sediment Control Webcast
• Accounting for Urban Stormwater Retrofits and Urban Filter Strips Webcast
• Plus, lots of retrofitting resources on our website here!
www.chesapeakestormwater.net
Please take a few moments to answer our 6 question survey to help us better serve your
needs in our 2014 webcast series.
We use this information to report it to assess our work, your needs and to report it to our funders
for future webcasts !
Evaluation
https://www.surveymonkey.com/r/ChesBayRestorationMDE
Upcoming Webcasts
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