surviving the local wip: a practical guide on nutrient accounting for the chesapeake bay tmdl
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Surviving the Local WIP:a practical guide on
nutrient accounting for the Chesapeake Bay
TMDL
Contact Info
Tom Schueler
Chesapeake Stormwater Network andEPA Chesapeake Bay Program Stormwater
Coordinator
Baltimore, MD
watershedguy@hotmail.comwww.chesapeakestormwater.net
www.cbstp.org
Key Topics
• Some nutrient math • Some basics on the Bay TMDL • 12 easy steps to comply with your
local load allocation • Discussion
Technical Bulletin # 9Nutrient Accounting Methods to Document Local
Stormwater Load Reductions in the Chesapeake Bay
• Nutrients and the Chesapeake Bay• Why we need to become nutrient accountants• What we know about nutrients and stormwater• Tools to estimate nutrient loads• Defining the local baseline load• Pollutant removal rates for urban BMPs *• Strategy for achieving local load reductions• Analyzing the cost of implementation
* official CBP rates and proposed interim planning rates
Urban NutrientsWhere do they come from?
There are many sources of N and P in the urban environment
Relationship of Atmospheric Deposition to Urban Runoff Quality
NutrientAtmospheric Deposition 1
Stormwater Runoff Load 2
Pounds per impervious acre per yearTotal Phosphorus 0.7 2.0Total Nitrogen 13 to 17.0 15.41 measured rates during Washington NURP Study (MWCOG, 1983)2 Simple Method annual stormwater runoff loads for one acre of impervious cover (Schueler, 1987)
Much of the nitrogen in urban runoff is derived from atmospheric deposition, either in the form of dryfall or wetfall
Other sources of nitrogen in urban runoff include:
• Washoff of fertilizers• Nitrogen attached to eroded soils and streambanks • Organic matter and pet wastes on IC
What we know about turf and its management in the Bay Watershed
• 3.8 million acres of turf• Represents 9.5% of watershed area• Exceeds area devoted to row crops (corn, wheat, soybeans)• 75% of turf is home lawn
Nitrogen EMCs for different urban land covers
Urban Land Cover Total N (mg/l)
Lawns 9.70
Highway 2.95
Streets (Variable) 1.40
Parking Lots 1.94
Rooftops 1.50
Source; CWP, 2003
Runoff sampling shows that lawn runoff is very high in nitrogen. Also, rooftop runoff concentration shows effect of atmospheric deposition
About 50% to 65% fertilize their yard
15 to 20% hire lawn care company
Average of two applications per year
50% of homeowners over-fertilize
Estimated N Fertilizer inputs by lawns: 215 million lbs/yr
What do we know about home lawns and nutrients?
What have you been hearing about the Chesapeake Bay TMDL ?
Bottom Line of Chesapeake Bay TMDLFor Urban Suburban Sector
~25 to 30% TP and TN load reductions needed from existing development (plus sediment reductions)
No increase in future load as a result of growth and development
60% of the reductions to be achieved by 2017
100% by 2025
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Some folks think the WIP process is scary
• Billions in potential costs• Short planning horizon (draft plan due Dec 1, 2011)• Potential regulatory liability • High planning costs • Lots of complex documents
= major local headaches
The WIP Process is not as Scary as it Looks
• Each state works with its local governments to develop strategies for nutrient reduction
• The jurisdictional unit could be a MS4 permitee, planning district commission, county or conservation district, depending on the state
• The liability for not meeting the load reductions is a state liability, and not a local one (unless tied into MS4 permit)
What to expect:
• Locals will need to submit data, have a strategy and report on BMP implementation
• Locals will need to follow state and/or CBP approved procedures for tracking and verifying BMPs
• States have the responsibility for aggregating local data and submitting it to EPA to show progress in load reductions
The WIPs are a long term process
• Progress is assessed based on two year milestones
• Implementation of the WIP is a 15 year iterative process
• Many opportunities for adaptive management and collaboration
Check with your state agency to find who is responsible for WIPs in your state and the process they will follow
(they differ a lot)
A practical local strategy to meet the local WIP
BMP Credit Lead Agency Other Stakeholders
Watershed Mapping/Planning Planning, GIS Local watershed group
Stormwater Retrofits DPW or stormwater review agency
Schools, parks, roads, and other public land
New Development Stormwater review agency Land use planning
Maintenance Upgrades DPW Maintenance crew CIP budgets
Stream Restoration Environmental resources Parks
Redevelopment Credits Stormwater review staff Planning agency
Reforestation Community forestry andSite planning agencies
Parks, street trees, schools
Street Sweeping DPW Maintenance Crew Street maintenance
Urban Fertilizer Management MS4 Permit holder Cooperative Extension
Septic Hookups/Upgrade Sanitarian wastewater Utility
Illicit Discharge Elimination MS4 Permit holder Watershed groups
Wetland/shoreline Restoration Local environmental agency
Land conservancy
Step 1 Organize a local watershed implementation team
Initial Tasks for the Watershed Team
• Obtain the local nutrient reduction allocation from the state or regional agency administering the TMDL
• Coordinate with the state TMDL agency to better understand their local expectations
• Analyze local land use and land ownership data to determine what part of their load allocation can be legitimately excluded
• Identify which local agencies or stakeholders have primary responsibility to implement the dozen available urban BMP credits
• Check to see if agencies are already implementing a credit, or could do so through modest changes to existing programs.
• Determine how the credits should be documented and reported to the appropriate state or regional agency
# 2 Take credit for fertilizer reductions on urban turf
• Reflects recent MD and VA P Ban in Fertilizer
• Modeled as an application reduction, with an estimated 17 to 19% TP reduction in urban loads
• Research in other regions put it closer to 10 to 12%
• TN reductions are minor unless regional education campaign program to reduce N fertilization
Right now, none of our residential stewardship programs focuses on reducing urban fertilizer use, despite the fact it is the most cost effective nutrient reduction strategy
• 1.5 million acres of home lawn are fertilized
• Very limited incentives beyond free soil testing and passive technical advice • We send conflicting messages to homeowners about lawn fertilization
Urban NitrogenFertilizer Reduction
Fertilizer Message 1 • Get a soil test, and if adequate P is
present, then select P-free fertilizer
• Calibrate your spreader
• Follow label directions of weed/feed products
• Use slow release N fertilizer in Fall only
• Apply 1 to 4 lbs of actual N per 1000 square feet
• Do not apply to frozen soils, impervious cover or in advance of a thunderstorm
• Use a composting lawn mower and recycle composted leaves over yard
• Set mower height at three inches
• Irrigate only after extended drought
• Don’t washout your spreader over IC
Fertilizer Message 2
Tommy makes an offer you can’t refuse!
• Keep your spreader in the garage for the next three years to protect the Bay
• Save 150 bucks and three weekend days
• If you still like the look of your lawn after three years we will buy back your spreader for $150
• If you think your lawn looks like crap, we will pay for a lawn makeover worth $500 (using our green lawn service)
The Competing Fertilization Message
Consumer surveys indicate the primary and almost exclusive sources for information on fertilizing their lawns are:
• TV and radio commercials
• Product labels in the big box store
• Store attendants
• Recommendation from their lawn care company
# 3 Take nutrient reduction credits for more stringent stormwater requirements at redevelopment projects
• Calculate the expected acres of impervious cover slated for redevelopment
• Estimate the runoff capture volume and design level using new regs
• Calculate the aggregate nutrient reduction credit
Nutrient Reduction Credits for RedevelopmentLbs/acre/year
NutrientRainfall depth for which stormwater treatment is computed (inches)
0.25 0.50 0.75 1.0 1.25 1.5LO1 HI2 LO HI LO HI LO HI LO HI LO HI
Total P 0.4 0.6 0.6 0.9 0.75 1.1 1.0 1.5 1.25 1.65 1.4 1.8
Total N 3.3 4.5 5.1 6.8 6.3 8.4 8.4 11.3 9.9 12.3 11.1 13.5
Multiply aggregate acres of redeveloped IC by the per acre load reduction credit
Can be an important strategy in several Bay cities
# 4 Become an Early Adopter of Stormwater Regulations
This ensures that your nutrient liability won’t continue to increase
Variability in Bay State Stormwater Regulations
• Considerable confusion in terminology among the states (ESD, LID, RR, treatment trains)
• Each state/locality is on a different schedule for implementing them (2009 to 2013)
• Each state has a unique hydrologic performance standard
• Differential standards for new and redevelopment• Individual sites may not fully comply with
standard
Will the new standards lead to nutrient neutrality for new development projects in the future ?
TP Loads, By Land Based Sector in Maryland Bay TMDL
Loading Sector 2009 Load Target Load
Million pounds per year
Forest Runoff 0.35 0.35Urban and Suburban Runoff
0.67 0.44
Agricultural Runoff 1.44 1.25ALL RUNOFF SOURCES 2.46 1.99 3
Acceptable Load (lbs/acre) 0.56 0.34excludes CAFO portion of agricultural runoffWastewater sources excluded
Same Analysis Yield an Acceptable TN Load of 4.4 lbs/acre
Results differ slightly for each state based on distance to the Bay
What is an acceptable runoff nutrient load?
What local safeguards are needed to ensure the load limits are actually achieved on the ground?
Practices designed in accordance with Bay-wide Design Specs
Post-construction certification that it was installed properly and works
Municipality meets minimum performance standards for:
ongoing performance inspections maintenance enforcement
• Set goal to reforest 5% of current turf cover
• 10 to 1 Rule (ten acres of reforestation equals one acre of impervious cover treated)
• CSN and VADCR spreadsheet rates are about the same
• Get extra credit for•Treating runoff from adjacent IC • Stream or shoreline buffer upgrades ?
# 5 Take Credit for Community Reforestation
# 6 Take credit for current and future stream restoration projects
• High nutrient reduction rates for qualifying projects• Provides both a local benefit and a Bay benefit• Generally popular with the public• Cost competitive with pond retrofits
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Proposed Interim Stream Restoration Rate
Removal rate per Linear foot of Qualifying Stream Restoration Source TN TP TSS
CBP 2005 N=1
0.02 lbs 0.0035 2.55 lbs
CSN 2011 N=6
0.20 lbs 0.068 lbs 310 lbs
U of MD StudyN=25+
Scheduled for early 2012
CBP BMP Panel to Update Stream Restoration Rates
• U of MD Literature Review• Review of 20 + studies on various parts of the urban stream nutrient cycle• Develop concept model for predicting rates• Should be done by early 2012
What’s a Qualifying Project?
Can’t just dump rip-rap
Comprehensive stream design
Flood plain re-connection
Minimum reach size
In-stream habitat features
# 7 Re-tool your stormwater maintenance program
Inspect the performance of your existing BMP inventory
Field Research Indicates about 30% of the BMP Inventory needs a makeover
Significant nutrient reductions are possible through these low cost “BMP makeovers”
Performance downgrades must be reflected in local WIP baseline load
By Retooling existing Maintenance Budget, it is possible to eliminate eyesores and clean the Bay
Thirty Years of BMPs. The BMP Inventory in a Maryland County
Potentially High Performers Known Low Performers
Bioretention/Dry Swales
49 Underground Detention
270
Sand Filters 279 Dry Ponds 528
Wet pond 212 Oil Grit Separators 805
Pond Wetland 98 Proprietary Practices
239
Infiltration Basin 58 Flow Splitter 321
Infiltration Trench 459 Other (plunge pools) 30
Adapted from MCDEP 2006 3350
Dealing with the Local BMP Legacy
# 9 Take the Mass Credit for Intensive Street Sweeping
• New CBP Method based on Actual Pollutant Mass Picked Up• Qualifying Frequency and Technology• Incentive for Sweeping Crews to Maximize Pickup
# 9 Investigate Septic Hookups and Upgrades
• Key Strategy for TN removal • Relict septics in sewered
catchments• Upgrade N technology in
existing septics• Sewer extensions and
cluster satellites • CBP Rates available
# 10 Take Credit for Eliminating Illicit Discharges
• For chronic and episodic sewage discharges that are physically eliminated
• Reduction based on rate of dry weather flow and outfall concentration above background levels
• CWP research indicates this can be an important strategy in some urban watersheds available
Source: CWP
# 11 Retrofit Existing Stormwater Ponds
# 12 Residential LID Retrofits
Subsidies, technical assistance, stormwater utility credits and other incentives to build LID retrofits on private land
The Cost Challenge
The weakest link in local WIPs are accurate cost data for practices
Need to acquire better cost data and share it
Possibility of Bay-wide database
Millions vs. billions
Discussion:
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