TMDL Monitoring and Assessment Plan Development Robert J. Potts E Sciences, Incorporated
Part VIII.B.2 (b) Monitoring and Assessment Plan Development Review of Plan requirements: Developed for the prioritized TMDL water body Only for non-bacteria TMDLs Due within twelve (12) months of date of permit issuance Approved by FDEP
Part VIII.B.2 (b) Monitoring and Assessment Plan Development Purpose of Monitoring and Assessment Plan: Collect data Identify major sources of the pollutant of concern Assess progress towards addressing TMDL WLA
Part VIII.B.2 (b) Monitoring and Assessment Plan Development Two options: Targeted Water Quality Monitoring Approach Watershed focus Storm Event and Outfall Monitoring Approach MS4 focus
Targeted Water Quality Monitoring Approach Goal: Collect estimates of annual pollutant loadings Identify major sources of the pollutant of concern Identify pollutant load reduction opportunities Evaluate the water body health over time Determine progress toward addressing TMDL WLA
Targeted Water Quality Monitoring Approach Plan Requirements: Map of monitoring locations Within the receiving water(s) Near MS4 outfall locations Biological and sediment monitoring (if applicable)
Targeted Water Quality Monitoring Approach Describe monitoring methods Water quality: auto-sample, grab sample Vegetation: Lake Vegetation Index, Linear Vegetation Survey
Targeted Water Quality Monitoring Approach Monitoring frequency Monthly, quarterly, annually Stormwater projects or retrofit opportunities Target areas for improvement Old neighborhoods, commercial, or industrial areas Narrative of plan s ability to evaluate stormwater pollutant loadings and water body health trends
Targeted Water Quality Monitoring Approach Identify major sources of loading Identify opportunities for load reduction
Goal: Obtain flow-weighted composite samples from MS4 outfall Provide baseline pollutant loading from MS4 Identify major sources of the pollutant of concern Identify pollutant load reduction opportunities Determine progress toward addressing TMDL WLA
Plan Requirements: Identify Load Assessment Point Map of monitoring location(s) Sampling method and frequency Identify parameters Narrative detailing plan s ability to evaluate stormwater pollutant loadings over time
Load Assessment Point MS4 stormwater outfall, or Point of interconnection
MS4 Stormwater Outfall
Point of Interconnection
Outfall Prioritization Plan Required to determine Load Assessment Point(s) Use the following factors: Estimated annual loading using water quality data, Estimated annual loading using EMC & rainfall, or Planned retrofit project Note: if only one (1) outfall or point of interconnection, permittee shall use that as the Load Assessment Point
Example: Lake Adelaide (WBID 2998E) Prioritized by Altamonte Springs & FDOT Impaired for TN and TP Monitoring and Assessment Plan submitted in July, 2013
The City requested analysis of the Lake Review historic WQ data from 1992-2007 Analyze watershed characteristics Develop hydrologic budget of input and losses Develop nutrient budget of input and losses Provide recommendations for management plan Completed by PEC and ERD
Identification of Load Assessment Point A total of nine (9) sub-basins for watershed Five (5) piped outfalls discharge to Lake Adelaide
Pollutant loading analysis Sub-basin 14 identified as Load Assessment Point 36 inch RCP Contributing area: 62% City and 38% FDOT
Outfall monitoring Auto sampling equipment installed Parameters: TN, TP, No x, Organic N, TSS, Ammonia, ph, Alkalinity Scheduled for 4 month period (wet / dry season)
Sediment sampling Moisture content TN, TP, ph, Organic content Density Phosphorous speciation
Monitoring and Assessment Plan Approaches Pros and Cons Targeted Water Quality Monitoring Approach Provides long-term trends of waterbody Better data for management decisions Hard to discern MS4 influence
Monitoring and Assessment Plan Approaches Pros and Cons Storm Event and Outfall Monitoring Approach MS4 specific Can be costly and labor intensive Rainfall dependent
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