Department of the Environment
Maryland Coastal Bays: TMDL Development Update
Timothy C. Rule
Maryland Department of the Environment
January 5, 2011
Presentation Outline
•
Schedule and Status of TMDL Development
•
Modeling Approach—Brief Review
•
Accomplishments During 2010
•
Impairments and TMDLs
in Coastal Bays—Recap
•
Water Quality Standards and TMDL Modeling Endpoints for Coastal Bays TMDLs
•
Scenario Runs
•
Q&A and Discussion
TMDL Development Schedule and Status
•
Watershed Model: Baseline Loads Delivered to VIMS: January
•
Water Quality Model:–
Final Calibration: February 2011
–
Scenario Runs: March –
April 2011
•
TMDL Documentation: January –
April 2011
•
TMDL Review: May –
August 2011–
Includes Public Review and Meeting (late July)
•
Submittal to EPA: September 2011
MDE’s
Modeling Approach•
Linked modeling system –
Watershed Model (HSPF)
•
University of Maryland•
Complete; transferred to MDE
–
Major updates/improvements in last year
–
Hydrodynamic Model/Water Quality Model (UnTRIM/CE-
QUAL-ICM) •
Virginia Institute of Marine Sciences
–
Includes sediment process component
Land Use
•
Delaware (Inland Bays model)••
Delaware Department of Planning Land Use Database.Delaware Department of Planning Land Use Database.
•
Maryland••
Worcester County Land Use databaseWorcester County Land Use database
•
Virginia••
National Land Cover Data (USGS, 1999)National Land Cover Data (USGS, 1999)
••
CBPO land use classification used for agricultural CBPO land use classification used for agricultural categoriescategories
Watershed Model Segmentation
•
Calibration of Model Parameters (Birch Branch)
•
Validation (Bassett Creek)
•
Transfer of Model Parameters to Uncalibrated
Segments
Improvements to WSM over the last year:
•
Full Review and QA/QC of Land Use/Acreages
•
Review and Refinement of Automated Calibration Methods
•
Refinement of Parameter Transfer Methodology •
Verification of Consistency with Literature Values
•
Improvement of Barren Land Unit Loads
•
Addition of Shoreline Erosion
Impairments Under Investigation•
1996: All Coastal Bays listed as impaired by nutrients.
•
Existing TMDLs
(2002):–
(1) Newport Bay–
(2) Areas of Isle of Wight Bay (aka “Northern Coastal Bays”)
•
Current project addresses entire system:–
Areas addressed by previous TMDLs–
Assawoman
Bay (including Greys
Creek and Open Water)–
Isle of Wight Bay (Manklin
Creek and Open Water)–
Sinepuxent
Bay –
Newport Bay (Marshall Creek)–
Chincoteague Bay
Location of Existing TMDLs
Designated Uses, Criteria, and
TMDL Endpoints
Designated Uses in Coastal Bays
•
Use I: Water Contact Recreation/Protection of Aquatic Life
•
Use II: Support of Estuarine and Marine Aquatic Life and Shellfish Harvesting
Water Quality Criteria in Coastal Bays
•
Dissolved Oxygen:–
Numeric
Criteria
–
MD: ≥
5 mg/l DO at any time
–
VA: 5mg/L min/ 6mg/L daily average DO
–
DE: 5mg/L daily average DO
•
Chlorophyll a:–
Narrative
Criteria
–
In MD: Chlorophyll a concentrations in free-floating microscopic plants (i.e., algae) must not exceed levels that result in ecologically undesirable consequences
TMDL/Modeling Endpoints•
Must be protective of Designated Uses per Code of Maryland Regulations
•
Seek to protect SAV grow zones
–
Discussions w/MCBP staff led to consideration of chlorophyll a endpoints in context of salinity regimes
Salinity Regimes in Coastal Bays
•
Proposed Chlorophyll a endpoints:–
Polyhaline
areas: 90th
%ile
not to exceed 15 μg/L
–
Oligohaline: Not to exceed 50 μg/L
•
Will consider results of Natural Conditions modeling scenario
–
Mesohaline: Will depend on results of Natural Conditions modeling scenario
Modeling Scenarios:•
20 budgeted for; ≥
13 already dedicated
–
Current (Baseline) Conditions
–
Natural Conditions•
Natural land use, no anthropogenic inputs
•
Includes shoreline erosion
–
Incremental Loading Scenarios (4)
–
Geographic Isolation and Existing TMDL Scenarios (6)
Geographic Isolation/Existing TMDL Scenarios
Modeling Scenarios (Cont’d)•
TMDL Scenarios (Several)
•
Stakeholder-suggested scenarios (many encompassed above):–
Geographic Isolation of Chincoteague Island–
‘All or Nothing’
of the following:•
N-removing septic systems•
CAFOs•
Atmospheric Deposition•
OC WWTP Outfall•
Impervious Surfaces•
Cover Crops
•
Post-TMDL Development Scenarios Also Possible
TMDL Development Schedule—Recap
•
Modeling: January –
April 2011
•
TMDL Documentation: January –
April 2011
•
TMDL Review: May –
August 2011•
Mark your calendars: Public meeting mid-late July
•
Submittal to EPA: September 2011
Discussion/Questions?
Contact InformationMelissa Chatham
TMDL Technical Development Program, MDE/SSA
1800 Washington Blvd., Ste. 540
Baltimore, MD 21230
(410) 537-3937
Tim Rule
TMDL Technical Development Program, MDE/SSA
1800 Washington Blvd., Ste. 540
Baltimore, MD 21230
(410) 537-3688
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