62-330.451. General Permit to Counties, Municipalities, and other Agencies to Conduct Stormwater Retrofit Activities

(1) A general permit is granted to counties, municipalities, state agencies and water management districts to construct, operate, and maintain stormwater retrofit activities as authorized below for improving existing surface water and stormwater systems. This general permit may be used in conjunction with exempt activities.

(2) Types of stormwater retrofit activities authorized under this general permit are:

(a) Construction or alteration that will add additional treatment or attenuation capacity and capability to an existing stormwater management system;

(b) The modification, reconstruction, or relocation of an existing stormwater management system or stormwater discharge facility;

(c) Stabilization of eroding banks, and installation of structures such as gabions to limit bank erosion; or

(d) Excavation or dredging to remove sediments or other pollutants that have accumulated in existing surface waters as a result of stormwater runoff and stormwater discharges, provided the material removed is not deposited in existing wetlands or other surface waters.

(3) Stormwater retrofit activities shall not:

(a) Be proposed or implemented for the purpose of providing the water quality treatment or flood control needed to serve new development or redevelopment; or

(b) Include a dam that has more than 50 acre-feet of storage capacity if the dam is more than five feet high, nor a dam having a height of ten or more feet, regardless of storage capacity. Height is measured from the top of the dam to the natural bed of the stream or watercourse at the downward toe of the dam, or from the lowest elevation of the outside limit of the dam to the maximum elevation of the dam.

(4) There is no limit to the acreage of stormwater retrofit activities in artificial waters. Work in wetlands and non-artificial surface waters shall be limited to no more than 0.5 acre.

(5) A stormwater quality retrofit activity must result in at least one of the following:

(a) Addition of treatment capacity to an existing stormwater management system such that it reduces stormwater pollutant loadings to receiving waters;

(b) Addition of treatment or attenuation capability to an existing developed area when either the existing stormwater management system or the developed area has substandard stormwater treatment or attenuation capabilities, compared to what would be required for a new system requiring a permit under part IV of chapter 373, F.S.; or

(c) Removal of pollutants generated by, or resulting from, previous stormwater discharges.

(6) A water quantity retrofit project proposed to reduce existing flooding problems must be designed in such a way that the project does not:

(a) Result in a net reduction in water quality treatment provided by the existing stormwater management system; nor

(b) Increase discharges of untreated stormwater entering receiving waters.

(7) The project must be designed, constructed, and implemented as a complete, stand-alone project within the construction phase duration of a general permit, and such that it will not at any time during its construction or operation:

(a) Cause or contribute to any water quality violations;

(b) Contribute to any existing violation if it discharges pollutants into waters where existing ambient water quality does not meet water quality standards for those pollutants. In such a case, the project must include measures that will cause a net improvement in the receiving waters for those pollutants in accordance with section 373.414(1)(b)3., F.S.;

(c) Adversely affect the value of functions provided to fish and wildlife by wetlands or other surface waters;

(d) Adversely affect the hydroperiod of wetlands on adjacent lands or the hydroperiod of other wetlands upstream, downstream, or adjoining to the work area under subsection (4), above;

(e) Cause or contribute to increased flooding of adjacent lands or cause new adverse water quantity impacts to receiving waters;

(f) Add or increase any chemical treatment;

(g) Be operated by pumps or other mechanical or adjustable features; nor

(h) Adversely impact the maintenance of surface or ground water levels or surface water flows established pursuant to section 373.042, F.S.

(8) The entity conducting this general permit must conduct at least one pre-notice meeting with Agency staff having responsibility for the review of the proposed activities. The notice required in rule 62-330.402, F.A.C., shall include materials reflecting the recommendations of the Agency discussed during that meeting, and demonstrating compliance with the above, including a certification by a registered professional that the proposed activity will meet the criteria specified above. Such certification shall include appropriate design analyses, pollutant loading analyses, modeling and other engineering calculations, drawings, specifications and other information to support, describe, verify, and document the registered professional’s certification.

(9) Nothing in this general permit will preclude a county or municipality from obtaining and implementing a Basin Management Action Plan with water quality credits for activities performed under this authorization.

(10) Within 30 days after completion of construction, a registered professional shall submit certification that construction was completed in substantial conformance with the plans and calculations that were submitted in the notice to use this general permit.

Rulemaking Authority 373.026(7), 373.043, 373.118(1), 373.118(6), 373.406(5), 373.4131, 373.414(9), 373.418, 403.805(1) FS. Law Implemented 373.118(1), (6), 373.406(5), 373.413, 373.4131, 373.414(9), 373.416, 373.418 FS. History–New 10-1-13, Amended 6-1-18.