TMDLs and MS4 by OF6eor4

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									Fairfax County
TMDL Case Studies
   Kate Bennett, Stormwater Planning Division
   Department of Public Works and Environmental Services
   May 17, 2012
Outline
   Monitoring and Assessment
   Impaired Waters
   TMDL Development
       Bacteria TMDLs
       Benthic TMDLs
   Chesapeake Bay TMDLs
   TMDL Implementation
   MS4 Permitting
   Project Implementation
   Conclusions
Monitoring and Assessment
   DEQ Collects Water Quality Monitoring Data
       Surface Water
       Biological
       Probabilistic
       Fish Tissue
   DEQ Conducts Water Quality Assessments Every Two Years
       Guidance Developed For Each Assessment
       Five Year Assessment Window
           January 1, 2005 through December 31, 2010 for 2012 Assessment
       Monitoring Data Compared to Water Quality Standards (WQS)
       Waters that Do Not Meet WQS Are Identified as Impaired
           305(b)/303(d) Water Quality Assessment Integrated Report
Common Impairments in Virginia
    2010 Assessment Identified 1,585 Impairments
        Pathogens:          691 (44%)
        Benthic:            282 (18%)
        Dissolved Oxygen:   206 (13%)
        pH/Acidity:         162 (10%)
        Mercury              71 (4%)
        Temperature          55 (3%)
        PCBs                 49 (3%)
        Pesticides           19 (1%)
        Other                50 (3%)
    TMDLs Must Be Developed Within 12 Years of Listing
    More Than 1,350 TMDLs Developed to Date
Impaired Waters in Fairfax County
Impaired Waters in Fairfax County
Impaired Waters in Fairfax County
Impaired Waters in Fairfax County
TMDL Development
   A TMDL is a Pollution Budget
       How much of a pollutant can a surface water
        assimilate and still meet WQS?
       Pollutant-specific
   TMDL = Sum of WLA + Sum of LA + MOS
       WLA = Waste Load Allocations (regulatory
        implementation through permits)
       LA = Load Allocations (voluntary implementation)
       MOS = Margin of Safety (accounts for uncertainty)
   TMDL Development Approach and Implementation
    Measures Depend on Pollutant of Concern
Bacteria TMDLs
   Impaired Use: Recreation
Sources of Bacteria
Bacteria TMDL Development
   Bacteria Standard for primary contact in freshwater:
       Geometric Mean = 126 cfu/100 ml
           Requires at least four samples in a calendar month
       Instantaneous Maximum = 235 cfu/100 ml
           No more than 10% of total samples in five year assessment
            period may exceed
   Bacteria TMDL development methodology:
       Step 1: Data collection and watershed assessment
       Step 2: Source assessment
       Step 3: Computer modeling
       Step 4: Determine required reductions by source
Bacteria TMDL Implementation
   Staged Implementation Through BMPs
       Allows water quality improvements to be recorded as stream
        monitoring continues
       Provides quality control, given modeling uncertainties
       Provides mechanism for developing public support
       Helps ensure most cost effective practices are implemented first
       Allows evaluation of adequacy of the TMDL in achieving WQS
   Address Anthropogenic Sources First
       Leaking sewer lines
       Failing septic systems
       Pet waste
       Garbage collection
       Street cleaning
Benthic TMDLs
   Impaired Use: Aquatic Life
Benthic TMDL Development
   Benthic Standard is Narrative:
       “State waters […] shall be free from substances […] which
        are inimical or harmful to human, animal, plant, or aquatic
        life.”
   Benthic TMDL Development Methodology:
       Step 1: Data Collection and Watershed Assessment
       Step 2: Stressor Identification
       Step 3: Source Assessment
       Step 4: Identification of Reference Condition
       Step 5: Computer Modeling
       Step 6: Determine Required Reductions by Source
Benthic TMDL Implementation
   Staged Implementation Through BMPs
       Allows water quality improvements to be recorded as stream
        monitoring continues
       Provides quality control, given modeling uncertainties
       Provides mechanism for developing public support
       Helps ensure most cost effective practices are implemented first
       Allows evaluation of adequacy of the TMDL in achieving WQS
   Examples of Efficient Sediment BMPs For Both Urban
    And Rural Watersheds
       Infiltration and retention basins
       Riparian buffer zones
       Grassed waterways
       Streambank protection and stabilization
       Wetland development or enhancement
TMDLs in Fairfax County
   Bacteria: Fecal Coliform or E. coli
       Accotink Creek (Upper and Lower):               92-97% Reduction
       Four Mile Run:                                  95-98% Reduction
       Bull Run:                                       89% Reduction
       Pope’s Head Creek:                              94% Reduction
       Difficult Run:                                  90% Reduction
       Hunting Creek, Cameron Run, Holmes Run:         83% Reduction
   Benthic: Sediment identified as stressor
       Bull Run:            78% Reduction
       Pope’s Head Creek:   28% Reduction
       Difficult Run:       32% Reduction
   Benthic: Flow used as surrogate for identified stressor
       Accotink Creek:      50% Reduction (1-Yr 24-Hr In-stream Flow)
   PCBs: Tidal Potomac River Watershed: 75% Reduction
Chesapeake Bay TMDLs
   November 2010: EPA accepted Virginia’s Phase I Watershed
    Implementation Plan (WIP)
       90% implementation of non-structural practices by 2017
       Retrofits of existing urban lands to reduce loads
           Impervious urban lands:    9% TN, 16% TP, 20% TSS
           Pervious urban lands :     6% TN, 7.25% TP, 8.75% TSS
       MS4s must achieve 100% of reductions over 3 permit cycles
           Years 1 to 5:     5% of required reductions
           Years 5 to 10:    35% of required reductions
           Years 10 to 15:   60% of required reductions
   December 2010: EPA issued the Chesapeake Bay TMDLs
       Assigned individual WLAs to Phase I MS4 Permits in Virginia
Chesapeake Bay TMDLs
   Phase II WIPs: Divide the Bay TMDL into Local Targets
       March 2011: EPA Expectation for Phase II WIPs
           “Clear, quantitative goals such as local area nitrogen, phosphorus
            and sediment targets, BMP implementation levels, and/or
            programmatic milestones”
       September 2011: VA Letter to EPA
           “The model, as currently constructed, is not appropriate for use in
            assigning loads in permits, developing local load targets, or
            measuring reduction progress”
       October 2011: EPA Letter to VA
           “Focus on meeting the major river basin planning targets in each
            jurisdiction [i.e. States and D.C.] rather than loading targets in
            each county or sub-watershed”
   March 2012: Virginia Final Phase II WIP submitted to EPA
       Public Comment Period Ends May 31, 2012
Chesapeake Bay
Watershed Model
Segments in
Fairfax County
TMDL Implementation
   Following EPA Approval of TMDL:
       WLAs implemented through permits (regulatory)
       TMDL Implementation Plan (IP) developed for LAs
        (voluntary)
   TMDL IPs not a Federal Requirement, but Required Under
    Virginia Law (WQMIRA) and Must Include:
       Date of expected achievement of water quality objectives
       Measurable goals
       Necessary corrective actions
       Associated costs, benefits, and environmental impact
   May Have Additional Requirements to Qualify for EPA
    Section 319 Funding
MS4 Permitting
   1972: Clean Water Act Established the National Pollutant
    Discharge Elimination System (NPDES)
   1975: NPDES delegated to Virginia
       Virginia Pollutant Discharge Elimination System (VPDES)
   1987: Municipal Separate Storm Sewer Systems (MS4s)
    Added to NPDES
   1990: Phase I NPDES Developed
       Large and medium MS4s (more than 100,000 residents)
       Industrial activities (11 categories regulated)
   1999: Phase II NPDES Program for Small MS4s
   2005: MS4 Program Transferred from DEQ (VPDES) to DCR
    Virginia Stormwater Management Program (VSMP)
   Fairfax County’s Phase I MS4 Permit Expired in 2007
Fairfax County’s MS4
 42,000 Storm Drainage Inlets
  and Catch Basins
 3,350 Private Stormwater
  Management Facilities
 1,350 Public Stormwater
  Management Facilities
 1,500 Miles of Pipe

 6,850 Regulated Outfalls

 79 Miles of Manmade
  Channels
 22 State Regulated Dam Sites
MS4 Permit Overview
   Permit issued to Fairfax County
       Compliance coordinated by Stormwater Management (STW)
   Authorizes specific discharges from MS4 to waters of
    the state/U.S.
       Outfall-based
   Requires development and implementation of an
    MS4 Program Plan to:
       Reduce the contamination of stormwater runoff
       Prohibit illicit discharges
MS4 Program Components
MS4 TMDL Action Plans
   Develop TMDL Action Plans Within 36 Months
       Include a schedule with interim benchmarks for implementation
       Developed in a manner consistent with the WLA
       Implemented in multiple phases using adaptive iterative approach
   Ensure Implementation of the Following BMPs
       Summary of the contributing MS4 areas
       Identification of existing source controls (type, acres treated,
        estimated load reduction)
       Identification of additional source controls necessary
       List of specific source controls to be implemented during permit term
        and implementation schedule
       Long-term monitoring to characterize MS4 contributions and detect
        improvements resulting from implementation of action plans
       Estimated cost to implement the BMPs identified
Project Implementation
   Stream Restoration: Dead Run (Before & During)
       Length Restored: 1,400 linear feet
    Project Implementation
       Stream Restoration: Dead Run (After)




Area Treated    Phosphorous Removal   Nitrogen Removal   Sediment Removal
   (acres)            (lbs/yr)             (lbs/yr)          (tons/yr)
    415                 28                     420             2.5
Project Implementation
   Outfall Restoration – Dolley Madison Library (Before)
       Length Restored: 150 linear feet
     Project Implementation
        Outfall Restoration – Dolley Madison Library (During & After)




Drainage Area    Phosphorous Removal    Nitrogen Removal    Sediment Removal
   (acres)             (lbs/yr)              (lbs/yr)           (tons/yr)
     5.4                  7.5                  68.6                1.2
    Project Implementation
       Detention Basin Retrofits – Sycamore Ridge (Before & After)




Area Treated   Phosphorous Removal    Nitrogen Removal   Sediment Removal
   (acres)           (lbs/yr)              (lbs/yr)          (tons/yr)
    78.4                38                   202                 9.4
    Project Implementation
       LID: Permeable Pavers – Sherwood Library (During & After)




Area Treated   Phosphorous Removal   Nitrogen Removal   Sediment Removal
   (acres)           (lbs/yr)             (lbs/yr)          (tons/yr)
    1.7                 1                    5                 0.6
    Project Implementation
       LID: Rain Garden – Fort Hunt Elementary (During & After)




Area Treated   Phosphorous Removal   Nitrogen Removal   Sediment Removal
   (acres)           (lbs/yr)             (lbs/yr)          (tons/yr)
    0.7                 1                    6                 0.5
Conclusions
   Review Biennial Water Quality Assessments
       Be aware of impairments and their causes (if known)
   Participate in TMDL Development
       Serve on TMDL Technical Advisory Committees (TACs)
       Encourage stakeholder attendance at Public Meetings
       Understand pollutant sources, assumptions made, reductions
        required and by whom
   Participate in TMDL IP Development
       Opportunity to coordinate with other stakeholders, share ideas and
        solutions
   Continue to Implement BMPs Using Adaptive Iterative Approach
   Stormwater Revenues Must Rise Significantly in Order to
    Comply With New/Pending Requirements
       Will require cultural change and public acceptance
Questions?
    Kate Bennett, Stormwater Planning Division
    Department of Public Works and Environmental Services
    kate.bennett@fairfaxcounty.gov

								
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