A stormwater management system shall be designed and installed for all land development projects that will contain features to provide for pollution abatement, recharge where possible, and protection from flooding.
(A) Pollution abatement: St. Johns River Water Management District's current criteria for pollution abatement shall be required of all land development projects. Refer to Table 1. Stormwater Treatment Criteria, Chapter 40C-41, F.A.C. (see Table 1, Pages 2 and 3).
(B) Recharge (where possible): In areas of Type A soils (as described by the U.S.D.A Soil Conservation Service), the total volume of runoff from the 25 year, 24 hour post-development storm event must be retained.
(C) Protection from flooding:
(1) In areas that have positive outfall (e.g. areas that drain to wetlands, streams, rivers, or lakes that have a direct hydraulic connection to either the Atlantic Ocean or the Gulf of Mexico), the St. Johns River Water Management District's Peak Discharge Criteria must be met for each drainage basin within all land development projects. Refer to Section 10.3, Page 36, of the St. Johns River Water Management District Applicant's Handbook for the Management and Storage of Surface Waters.
(2) In areas that drain to closed basins (depressions, wetlands or lakes which do not have a positive outfall), the St. Johns River Water Management District's volume criteria must be met for each drainage basin within all land development projects. Refer to Section 10.4, Page 39, of the St. Johns River Water Management district Applicant's Handbook for the Management and Storage of Surface Waters.
(3) In special flood hazard areas as indicated by the Federal Emergency Management Agency's Flood Insurance Study and Flood Insurance Rate Map of September 28, 2007, all proposed commercial, industrial, and residential structures are to be floodfree during the 100-year frequency, 24-hour duration storm event.
(4) The finished floor elevation of all habitable structures shall be a minimum of 1.5 feet above the centerline of the road way or based on an Engineer's detailed design showing that flow of stormwater drainage will be diverted around and not impact the structure.
Table 1 Stormwater Treatment Criteria Chapter 40C-42, Florida Administrative Code St. Johns River Water Management District | ||
Type of Treatment System | Class III Receiving Water Classification | |
Table 1 Stormwater Treatment Criteria Chapter 40C-42, Florida Administrative Code St. Johns River Water Management District | ||
Type of Treatment System | Class III Receiving Water Classification | |
Retention, Underdrain, & Exfiltration | Option #1 Off-line Treatment | Option #2 On-line Treatment |
0.5 inches of runoff or 1.25 inches times impervious area, whichever is greater. | 0.5 inch additional treatment volume over that required in Option #1. | |
Filtration | Option #1 Off-line Treatment | Option #2 On-line Treatment |
1.0 inches of runoff or 2.5 inches times impervious area, whichever is greater. | 0.5 inch additional treatment volume over that required in Option #1. | |
Wet Detention | On-line Treatment | |
1.0 inch of runoff or 2.5 inches times impervious area, whichever is greater. | ||
14-day residence time | ||
Littoral Zone (or 21-day residence time) | ||
Swale | On-line | |
80% of the runoff from the three-year, one hour storm | ||
Wetland Treatment | On-line | |
1.0 inches of runoff or 2.5 inches times impervious, whichever is greater | ||
Stormwater Treatment Criteria Chapter 40C-42, Florida Administrative Code St. Johns River Water Management District | ||
Type of Treatment System | Class I, Class II, and OFW Receiving Water Classification | |
Stormwater Treatment Criteria Chapter 40C-42, Florida Administrative Code St. Johns River Water Management District | ||
Type of Treatment System | Class I, Class II, and OFW Receiving Water Classification | |
Retention, Underdrain, & Exfiltration | Option #1 Off-line | Option #2 On-line |
50% additional treatment volume over Class III Option #1 treatment criteria. | Runoff from the three year, one-hour storm or 50% additional treatment volume over Class III Option #2, whichever is greater. | |
Filtration | Option #1 Off-line | Option #2 On-line |
50% additional treatment volume over filtration Class III Option #1 treatment criteria. | Runoff from the three year, one-hour storm or 50% additional treatment volume over Class III Option #2, whichever is greater. | |
Wet Detention | Option #1 On-line | Option #2 On-line |
Pretreatment pursuant Class III retention, exfiltration, or under-drain criteria in addition to Class III wet 21-day residence time detention criteria. | 50% more treatment volume over Class III criteria. 21-day residence time. Littoral Zone (or 31.5 day residence time). | |
Swale | On-line | |
Runoff from the three-year, one-hour storm | ||
Wetland Treatment | On-line | |
50% additional volume over Class III treatment criteria. | ||
(D) A permit from St. Johns River Water Management Districts required for all land development projects within the city limits of the city prior to obtaining a building permit and a copy of this permit, when issued, must be submitted to the city along with a copy of the maintenance agreement signed by the owner.
(Ord. 241, passed 11-27-85; Am. Ord. 632, passed 2-4-93; Am. Ord. 1263, passed 9-20-07; Am. Ord. 1464, passed 5-17-12)