The State of Florida’s TMDL & BMAP Process

TCAA Water Quality Review and Information-Sharing Program November 1, 2011

Mark Clark, Wendy Graham, Jeff Ullman and Kathleen McKee

Outline

Clean Water Act and Designated Uses Determining Water Body Impairment Setting TMDL Allocation of Load Iterative Process

Cuyahoga River June 22, 1969

Clean Water Act 1972

As part of the Federal Clean Water Act 1972, USEPA requested states develop: Designated uses for waters of the state (lakes,

reservoirs, rivers, streams, estuaries and wetlands),

Criteria that protect designated uses, Corrective process that would be implemented if

a designated use was not being met (i.e. if the waterbody was determine to be “impaired”)

Three step process to protect water uses

Designated Uses for Florida Waterbodies

Class I – Potable Water Supplies Class II – Shellfish Propagation or Harvesting Class III – Recreation, Propagation and

Maintenance of a Healthy, Well-Balanced Population of Fish and Wildlife

Class IV – Agricultural Water Supplies Class V – Navigation, Utility and Industrial

Use

F.A.C. Chapter 62-302 Surface Water Quality Standards http://www.dep.state.fl.us/legal/rules/shared/62-302.pdf

Example of Protective Numeric Criteria Dissolved Oxygen Criteria (Current)

Class I Shall not be less than 5.0.

Class II Shall not average less than 5.0 in a 24-hr period

and shall never be less than 4.0. Class III

Fresh-Shall not be less than 5.0. Marine-Shall not average less than 5.0 in a 24-hr

period and shall never be less than 4.0. Class IV

Shall not average less than 4.0 in a 24-hr period and shall never be less than 3.0.

Protective Narrative Nutrient Standard

State previously used a “narrative” standard to guide management and protection of waters from nutrient pollution

Rule 2-302.530 FAC “in no case shall nutrient concentrations of a

body of water be altered so as to cause an imbalance in natural populations of flora or fauna”

State presently in transition to a numeric nutrient standard

Corrective Process Florida’s Watershed Restoration Act Section 303(d) of the Clean Water Act (CWA)

requires states to submit lists of surface waters that do not meet applicable water quality standards (impaired waters)

The Florida Watershed Restoration Act (1999) clarified FDEP’s authority for the TMDL program and directed the Department to develop a methodology, to implement.

FDEP’s Watershed Management Approach - Five Phase Cycle

Phase 1: Watershed Evaluation, evaluate status of the quality of surface water and groundwater to identify potentially impaired waters for which TMDL’s may be needed.

Phase 2: Strategic Monitoring, verification of listing as impaired and to collect data for TMDL development

Phase 3: Developing and Adopting TMDL’s, prioritization of impaired waters then development and adoption of TMDL for basin.

Phase 4: Developing Watershed Management Plans, plan specifying how pollutant loadings from point and nonpoint sources of pollution will be allocated and reduced in order to meet TMDL requirements. (BMAP)

Phase 5: Implementing Watershed Management Plans, implementation of Phase 4

Basin Rotation

What if A Waterbody is Verified Impaired?

1. Determine source of Impairment Dissolved oxygen > excessive algae growth > nutrient

2. Determine threshold concentration or load of pollutant that will still maintain water body designated use (assimilative capacity)

3. Determine existing load to waterbody 4. Establish TMDL as difference between existing load

and assimilative capacity 5. Allocate required load reduction among watershed

stakeholders.

Mean TP vs. Algal blooms over 40ug/L (Walker and Havens 1995)

Example relationship between limiting nutrient (P) and chlorophyll-a

Determine Nutrient Budget

Water Column target concentration

(100 ppb)

Surface Inputs Surface Outflows

Sediment

Internal Loading (recycling)

Atmospheric Inputs

40 ppb

How much can be added and still maintain target water column concentration?

How much is presently being

added?

TMDL includes a Margin of Safety A margin of safety (MOS) is required as part of a TMDL in

recognition that there are many uncertainties in scientific and technical understanding of the chemical and biological processes that occur.

The MOS is intended to account for such uncertainties in a conservative manner that protects the environment.

According to EPA’s guidance, a MOS can be achieved through reserving a portion of the load for the future, or using conservative assumptions in calculating the load.

TMDL = ∑Point Sources + ∑Nonpoint Sources + Margin of Safety

Recommended Guidelines for TMDL Allocations

FDEP Formed Allocation Technical Advisory Committee (ATAC)

First step to achieve equity was to “level the playing field” in treatment effort between point and nonpoint sources. Point source are already required to provide, at a minimum, technology based treatment levels.

ATAC felt nonpoint sources should be expected to provide comparable minimum levels of treatment, before additional reductions were expected of point sources.

The ATAC subsequently decided that the comparable minimum treatment for nonpoint sources should be the Best Management Practice (BMPs) developed and adopted for that activity.

TMDL Allocation Example Maximum

load allowed (TMDL)

Allocation process address

this excess load

Step 1

Calculate the amount of pollutant reductions that would be achieved if: a) 45% of all agricultural and silviculture operations in

the basin and in upstream watersheds implemented the appropriate BMPs

b) 45% of all urban areas met stormwater treatment requirements for new construction, and

c) 45% of the homes with septic tanks within the 100-year floodplain were hooked up to a regional sewer system.

“all” does not include urban areas that are under Municipal Separate Storm Sewer Stormwater

Effect of Step 1 Reductions

40,000 pounds short

Step 2

If step 1 was not sufficient to meet the TMDL, then calculate if a) 90% of all agricultural and silviculture operations in the

basin implemented the BMPs, b) 90% of all urban areas met stormwater treatment

requirements for new construction, and c) 90% of the homes with septic tanks within the 100-year

floodplain were hooked up to a regional sewer system.

Effect of Step 2 Reduction

22,000 pounds short

If the reductions for step 2 were not sufficient to meet the TMDL, the third recommended step is to allocate reductions to all sources except those where loading is at background levels or those that have provided treatment beyond BAT levels, in increments of 10% until the TMDL is met.

Step 3

Effect of Step 3 Reductions

Step 1 10,000 lbs Step 2 28,000 lbs Step 3 15,000 lbs 53,000 lbs

Only need an 8% reduction in step 3, not 10 % reduction to meet TMDL target

Basin Management Action Plan

A Basin Management Action Plan (BMAP) is the primary tool to go about implementing the Total Maximum Daily Load (TMDL)

The process for BMAP development involves collaboration among local stakeholders and FDEP staff.

Once consensus among stakeholders over the BMAP has been achieved, it is adopted by Secretarial Order and enforced.

Iterative Process Continuous monitoring required to determine progress

toward target Use attainability is evaluated biannually Revisit TMDL target if use attainment is not met

Change TMDL or allocation if necessary

Efficacy of BMPs may be revised with more data which may require reassessment of load allocation

Summary TMDL Development is a multi step process Establishment of Criteria and TMDL’s are

often data limited and depend on models which can have many assumptions.

Margins of Safety are intended to provide for uncertainty and are conservative.

Allocation targets non-point sources first through implementation of BMP’s

Iterative process