Current through Reg. 50, No. 187; September 24, 2024
The practices listed below are set forth in this rule for the
purpose of evaluating compliance with this chapter. It is presumed the water
quality practices implemented in accordance with this section will provide
reasonable assurance that the system will comply with the performance standards
described in rule 40C-44.065, F.A.C. The water
quality practices or other alternatives shall be implemented to the extent
necessary to comply with the performance standards described in rule
40C-44.065, F.A.C. In some
cases, the implementation of these practices may not result in compliance with
the performance standards for issuance of an individual environmental resource
permit for an agricultural system. In those cases, the applicant shall provide
for implementation of such additional water quality practices and/or treatment
methodologies as necessary to provide reasonable assurance that the discharge
will comply with the performance standards described in rule
40C-44.065, F.A.C.
(1) Reduce the volume of stormwater and
associated wastewater discharged to waters of the state by:
(a) Implementing management practices
designed to reduce the volume of water discharged off-site, including Water
Table Control in Open Channels, Irrigation Land Leveling and Irrigation Water
Management, and
(b) Maximizing
onsite recycling to satisfy irrigation, freeze protection and pest control
needs. The applicant may demonstrate maximum stormwater harvesting by using all
the practically available water from reservoir storage prior to using
groundwater.
(2)
Implement and maintain a Conservation Plan, which includes a Nutrient
Management Plan and Pesticide Management Plan.
(3) Provide treatment of the pollutants
generated by the agricultural operation. The treatment method required depends
on the intensity of land use and associated pollutants.
(a) Wet detention ponds, designed and
operated in accordance with paragraph (b) or (c) below, are presumed to satisfy
the requirements of paragraphs (1)(b) and (3), for those portions of an
agricultural operation described below:
1.
Citrus, row crop, sod, hayland or improved pasture which discharge to Class I,
Class II, or Outstanding Florida Waters, or
2. Citrus, row crop, sod, hayland or improved
pasture on predominantly organic soils.
(b) Detention ponds which are part of an
existing surface water management system, and which comply with following
design and performance criteria are presumed to provide treatment.
1. Wet detention treatment volume is equal to
the first inch of runoff.
2. The
permanent pool volume provides an average residence time of 21 days during the
wet season (June through October). This volume may be determined by estimating
13.82% of the wet season average runoff. The permanent pool volume should be
recycled, pursuant to paragraph
40C-44.066(1)(b),
F.A.C.
3. No more than half the
treatment volume is drawn down in the first 60 hours following a storm event,
and the entire treatment volume is drawn down within 168 hours.
4. Pond depths below the water control
elevation shall not exceed an average of 5 feet or a maximum of 10 feet, unless
the applicant affirmatively demonstrates that the deeper depths will not cause
anaerobic conditions in the water column.
5. For ponds where interior borrow canals are
likely to result in short-circuiting of flows between the inlet and outlet, the
effective flow path shall be increased by adding diversion structures such as
canal plugs or baffles.
(c) Detention ponds proposed as part of a new
surface water management system which are designed, constructed and operated in
accordance with the following design and performance criteria are presumed to
provide treatment.
1. Wet detention treatment
volume is equal to the first inch of runoff.
2. The permanent pool volume provides an
average residence time of 21 days during the wet season (June through October).
This volume may be determined by estimating 13.82% of the wet season average
runoff. The permanent pool volume should be recycled, pursuant to paragraph
40C-44.066(1)(b),
F.A.C.
3. No more than half the
treatment volume is discharged in the first 60 hours following a storm event,
but at least half of the treatment volume is discharged within 72 hours
following a storm event.
4. Pond
depths below the water control elevation shall not exceed an average of 4 feet
or a maximum of 10 feet, unless the applicant affirmatively demonstrates that
the deeper depths will not cause anaerobic conditions in the water
column.
5. The treatment volume
should not cause the pond level to rise more than 18 inches above the control
elevation unless it is demonstrated that the littoral zone vegetation can
survive at greater depths and that the pond area ratio (drainage area/pond
area) is still sufficient to provide adequate treatment.
6. The pond design shall incorporate a
littoral zone or an alternate method to promote sedimentation. Littoral zones
shall be gently sloped (6:1 or flatter) to a point 2-3 feet below the
bleed-down or control elevation and extend to the top of the treatment volume.
The littoral zone and vegetation should be concentrated at the inflow (adjacent
to the sump, if required) and at the outfall.
7. The alignment and location of inlets and
outlets shall be designed to maximize flow paths in the pond. The pond shall
have a length to width ratio of a minimum of 2:1. If short flow paths are
unavoidable, the effective flow path should be increased by adding diversion
barriers such as islands, peninsulas or baffles to the pond. Inlet structures
should be designed to dissipate the energy of water entering the pond. Pumped
inflows must provide a sump to promote sedimentation and reduce water
velocities.
8. Pond design must
include permanent access for maintenance.
9. The bleed-down orifice invert elevation
shall be at or above the estimated wet season water table elevation. If the
orifice is proposed to be set below the wet season water table elevation,
groundwater inflow must be considered in orifice drawdown calculations,
calculation of average residence time, and estimated normal water level. For
ponds with pumped inflows, the applicant must demonstrate that the water table
of wetlands within the drainage area will not be significantly
lowered.
(d) Other water
quality practices in lieu of wet detention, such as overland flow, vegetative
filters and detention in isolated wetlands, are presumed to satisfy the
requirements in subsection (3), for low intensity agricultural operations such
as rough or semi-improved pasture, when the practice(s) is designed, operated
and maintained using accepted engineering principles.
(e) Agricultural surface water management
systems may incorporate overland flow, vegetative filters and detention in
isolated wetlands as water quality practices. Existing canals and conveyance
systems may be incorporated into a wet detention treatment system, when
appropriate. The applicant must provide reasonable assurance, through plans,
test results or other information, that the practice will provide an adequate
level of treatment to meet the performance standards above.
(4) Applicants who propose to satisfy the
performance standards in rule
40C-44.065, F.A.C., by employing
a treatment methodology or device other than those described in subsections
40C-44.066(1)
through 40C-44.066(3),
F.A.C., may seek approval for an equivalent alternative through the District's
permit process. The applicant must provide reasonable assurance, through plans,
test results or other information, that the alternative will provide an
adequate level of treatment to meet the performance standards
above.
Rulemaking Authority
373.044,
373.113,
373.171,
373.4131,
373.416,
373.418 FS. Law Implemented
373.016,
373.4131,
373.416 FS.
New 8-11-91, Amended 10-20-92, 10-3-95, 10-1-13,
6-1-18.
