Florida Administrative Code › 62 - DEPARTMENT OF ENVIRONMENTAL PROTECTION › 62 - Departmental › Chapter 62-4 - PERMITS › Section 62-4.244 - Mixing Zones: Surface Waters

Current through Reg. 50, No. 138; July 16, 2024
(1) Zones of
				mixing for non-thermal components of discharges.
(a) The Department may allow the water
				quality adjacent to a point of discharge to be degraded to the extent that only
				the minimum conditions described in subsection
				 62-302.500(1),
				F.A.C., apply within a limited, defined region known as the mixing zone. Under
				the circumstances defined elsewhere in this section, a mixing zone may be
				allowed to provide an opportunity for mixing and thus to reduce the costs of
				treatment. However, no mixing zone or combination of mixing zones shall be
				allowed to significantly impair any of the designated uses of the receiving
				body of water.
(b) A zone of mixing
				shall be determined based on the following:
1.
				The condition of the receiving body of water including present and future flow
				conditions and present and future sources of pollutants.
2. The nature, volume and frequency of the
				proposed discharge including any possible synergistic effects with other
				pollutants or substances which may be present in the receiving body of
				water.
3. The cumulative effect of
				the proposed mixing zone and other mixing zones in the
				vicinity.
(c) Except for
				the thermal components of discharges and nitrogen and phosphorus acting as
				nutrients, mixing zones which do not adhere to all of provisions paragraphs
				(1)(d) through (j), shall be presumed to constitute a significant impairment of
				the designated uses of surface waters of Classes I, II and III. An applicant
				for a mixing zone may obtain an exemption from these limitations as follows:
1. The applicant shall provide public notice,
				which shall be prepared or approved by the Department, in a newspaper of
				general circulation in the area in which the mixing zone is proposed. The
				notice shall identify the specific exemption it is seeking and notice the time,
				date and place of a public meeting at which, if the meeting is requested, the
				Department will consider comments to the requested exemption. The notice shall
				allow a person to request such a public meeting by contacting the Department
				within 14 days of the publication of the notice. If there is no such request, a
				public meeting is not required.
2.
				The applicant shall arrange for a public meeting which will be held if
				requested at which the Department will consider public comments on the
				exemption that is being sought. The Department shall also provide for public
				notice of the meeting in the Florida Administrative Register.
3. The applicant shall affirmatively
				demonstrate to the Department that the mixing zone exemption will not produce a
				significant adverse effect on the established community of organisms in the
				receiving body of water or otherwise significantly impair any of the designated
				uses of the receiving body of water.
4. The applicant shall affirmatively
				demonstrate to the Department that the requirements of paragraph (5)(c), of
				this rule, will be met.
(d) A mixing zone shall not include an
				existing drinking water supply intake or any other existing water supply intake
				if the constituents of such mixing zone would significantly impair the purposes
				for which the supply is used.
(e) A
				mixing zone shall not include a nursery area of indigenous aquatic life or any
				area approved by the Department of Environmental Protection for shellfish
				harvesting.
(f) In canals, rivers,
				streams, and other similar water bodies, the maximum length of a mixing zone
				shall be no more than 800 meters. In no case shall a mixing zone be larger than
				is necessary for the discharge to completely mix with the receiving water to
				meet water quality standards, and in no case shall a mixing zone significantly
				impair the designated use of the water body other than within the boundaries of
				the mixing zone.
(g) In lakes,
				estuaries, bays, lagoons, bayous, sounds, and coastal waters, the area of
				mixing zone shall be 125, 600 square meters unless a lesser area is necessary
				to prevent significant impairment of a designated use. In no case shall a
				mixing zone be larger than is necessary to meet water quality
				standards.
(h) In open ocean
				waters, the area of a mixing zone shall be 502, 655 square meters unless a
				lesser area is necessary to prevent significant impairment of a designated use.
				In no case shall a mixing zone be larger than is necessary to meet water
				quality standards.
(i) The mixing
				zones in a given water body shall not cumulatively exceed the limits described
				below:
1. In rivers, canals, and streams, and
				tributaries thereto and other similar water bodies: 10% of the total length,
2. In lakes, estuaries, bays,
				lagoons, bayous and sounds: 10% of the total area.
(j) Within mixing zones in Class I, Class II,
				and Class III waters, the turbidity shall not average greater than 41
				Nephelometric Turbidity Units above natural background.
(k) Mixing zones in Class IV and V waters are
				subject only to the provisions of paragraph (d), above, and of Rule
				 62-302.500, F.A.C., and shall
				not significantly impair the designated uses of the receiving body of
				water.