Presentation on theme: "Introduction to TMDLs for Nutrients Presented by: Dr. Scott Emery January 15, 2009."— Presentation transcript:
Introduction to TMDLs for Nutrients Presented by: Dr. Scott Emery January 15, 2009
Total Maximum Daily Load (TMDL) The maximum loading of a pollutant that can be discharged in a surface water and still meet its designated use and water quality standards. Not meeting its TMDL = Impaired
States Must: Identify impaired water bodies or segments Develop TMDLs Implement programs to eliminate the impairment
Nitrogen and Nutrient Impairment Rule 62-302.300 FAC, subsection 13: highlights excessive nutrients (e.g. nitrogen and phosphorus) as “one of the most severe water quality problems facing the state.” Statewide, nutrient impairment is the single largest category (others include bacteria, metals). Multiple water bodies and segments within Hillsborough County are involved in the TMDL issue.
Nitrogen is a major pollutant of concern in Tampa Bay -Excess nitrogen clouds the water and reduces sunlight so seagrasses can’t grow. -Baywide, residential runoff accounts for 20% of the total nitrogen load to Tampa Bay
TMDL =WLA Wasteload Allocation For Point Sources +LA Load Allocation For non-Point sources (incl. background) +MOS Margin of Safety Components of a TMDL
Source Type Examples of Point Sources Domestic wastewater treatment facilities Industrial wastewater treatment facilities Urban stormwater discharges from larger master drainage systems Some construction site stormwater Some industrial site stormwater Some animal feeding operations Examples of Non-point Sources Septic tanks Some types of urban/suburban/rural run-off Agricultural run-off Forestry Mining Mismanagement of household pesticides, yard trash, fertilizers, etc.
Compliance Strategy For each impaired water body/segment (WBID), for each type of impairment, a Basin Management Action Plan (BMAP) must be developed Requires definitive commitments from stakeholders, including the County. Meeting these TMDLs will, in all likelihood, require substantial money from the County to implement projects and programs. ( )
Costs to remove nitrogen from surface waters Costs to remove excess nitrogen from waterways can be significant. Stormwater retrofits can range from $40,000-$200,000 per ton (SWFWMD). Wastewater treatment upgrades are greater than that amount.
Fertilizer Management Fertilizer use is one possible source of nutrients (nitrogen and phosphorus) and FDEP has listed (FDEP 2005) the mismanagement of fertilizers as a possible non-point source of pollution.
Estimated Nitrogen Reductions from 50% Compliance with Fertilizer Management Ordinance Hillsborough County30 Tons Manatee County8 Tons Pinellas County6 Tons Clearwater1.5 Tons St. Petersburg7 Tons Tampa8 Tons
Project NameApprox. Cost Approx. Land Cost Approx. O&M Cost Description Balm Rd. Wetland$1,700,000ELAPP acquired 29 acre wetland creation treats agricultural runoff for about 1,200 acres prior to discharge to Bullfrog Cr. Cockroach Bay Restoration $877,000ELAPP acquired Constructed a stormwater pond, intertidal marsh, and wetland restoration to treat agricultural runoff prior to discharge to Cone Ranch Restoration $392,000Water Resource Services Acquired Constructed and planted 5 ponds and installed 10 ditch blocks in existing ditch systems to retain and treat stormwater East Lake Alum Facility $997,000SWFWMD acquired land for County $25,000 – $30,000/yr Alum treatment facility to treat stormwater from approx. 1,100 acre drainage basin Gibsonton on the Bay$1,077,000Used existing right-of-way Drainage improvements and stormwater treatment with 1 CDS* water quality unit and 1 Stormceptor** water quality unit Hillgrove & Stearns$2,700,000$220,000Drainage improvements and stormwater treatment with 2 ponds and 1 CDS* unit Mckay Bay/Eastshore Alum Facility $1,300,000Tampa Bay Water donated land $35,000 – $40,000/yr Alum treatment facility to treat stormwater from approx. 1,700 acre drainage basin * CDS – Continuous Deflective Separation unit used to separate solids from stormwater. Sediment and other solids along with associated other pollutants such as some nutrients and heavy metals are separated from the stormwater and collected in the unit. ** Stormceptor – Another type of unit used to separate solids from stormwater. Prepared January 14, 2009 - HCPWD HILLSBOROUGH COUNTY PUBLIC WORKS DEPARTMENT EXAMPLE NITROGEN-REDUCTION PROJECTS & COSTS