MIAMI-DADE COUNTY REGULATORY AND ECONOMIC RESOURCE
DEPT.
DIVISION OF ENVIRONMENTAL RESOURCE MANAGEMENT (DERM)
“THE PERMITTING PROCESS TO DISPOSE
OF STORMWATER VIA INJECTION WELL AND
DEWATERING”
STORMWATER AND DEWATERING
OVERVIEW
Part I
STORMWATER DRAINAGE WELL
 PURPOSE
 CONDITIONS WHERE STORMWATER DRAINAGE
WELL APPLIES
 PERMITTING PROCESS
 PHASE I REQUIREMENTS
 DESIGN CRITERIA
 PHASE II REQUIREMENTS
STORMWATER AND DEWATERING
OVERVIEW
PART II
DEWATERING
 DEFINITION
 DEWATERING METHODS
1. OPEN EXCAVATION
2. WELL POINT SYSTEM
 THE USAGE OF STORM WATER WELL IN DEWATERING
PROCESS IS PERMITTED OR EXEMPTED BY DEP
PART I
STORMWATER DRAINAGE WELL
PURPOSE
 DRAINAGE WELL IS APPLICABLE ONLY EAST OF
THE SALT INTRUDED LINE (1000 mg/L CHLORIDE
LINE)
 DRAINAGE WELL IS USED PRIMARILY IN COASTAL
AREAS WHERE SEEPAGE OR TRANSMISSIVITY IS
OFTEN NON-EXISTENT
 OR THE REQUIRED AMOUNT OF EXFILTRATION
TRENCH WILL NOT FIT INTO THE PROJECT AREA
SALT WATER INTRUSION LINE MAP
MIAMI-DADE COUNTY STORMWATER
DRAINAGE WELL REVIEW
REQUIREMENTS
 THE DRAINAGE WELL APPROVAL CONSIST OF (2)
TWO PHASES
PHASE I REQUIREMENTS
 SUBMIT A STORMWATER DRAINAGE WELL
REVIEW APPLICATION FORM & FEE $210.00
PHASE I REQUIREMENTS
 3 SETS OF SIGN AND SEALED PAVING AND
DRAINAGE PLANS
 1 COPY OF SIGN AND SEALED DRAINAGE
CALCULATION
 1 COPY OF PROOF OF OWNERSHIP
 1 COPY OF PLUMBING PLAN
DESIGN CRITERIA
 CLASS
V INJECTION WELL (STORMWATER
DRAINAGE WELL ) REQUIRING WATER QUALITY
ANALYSES TO BE PERFORMED SHALL BE IN
ACCORDANCE WITH MIAMI-DADE COUNTY
CRITERIA
MIAMI-DADE COUNTY DESIGN
CRITERIA
 DRAINAGE CALCULATIONS MUST DEMONSTRATE
THE RETENTION OF 5 YEAR- 1 DAY STORM
EVENT.
 PROVIDE WATER QUALITY PRE-TREATMENT
PRIOR TO DISCHARGE INTO THE WELL.
 IN LIEU OF WATER QUALITY TREATMENT
PROVIDE POLLUTION CONTROL BOX SIZED
BASED ON 90 SECONDS DETENTION TIME
MIAMI-DADE COUNTY DESIGN
CRITERIA
 All INTERIOR DRAINS OF PARKING GARAGE AND
PLANTER DRAINS ARE SEPARATED FROM THE
STORMWATER DRAINAGE WELL SYSTEM AND
ARE ROUTED INTO A SPECIAL FRENCH DRAIN
WITH 2 FEET SAND FILTER BELOW THE PIPE
INVERT.
 A COPY OF THE PLUMBING PLAN MUST BE
SUBMITTED FOR VERIFICATION BY DERM OF AN
EFFECTIVE SEPARATION.
SPECIAL FRENCH DRAIN
DIAGRAM
CALCULATION OF THE REQUIRED 90
SECONDS DETENTION
 CALCULATE RUNOFF BASED ON THE RATIONAL
FORMULA
Q= CIA
REQUIRED = Q x 90 SECONDS
VOLUME REQUIRED ≤ VOLUME OF BOX
DERM APPROVAL STAMP
PHASE II REQUIREMENTS
 THE PROPOSED SITE MUST HAVE COMPLETED
PHASE I REQUIREMENTS AND COMPLIES WITH
MIAMI DADE COUNTY CRITERIA.
 3 COPIES OF FDEP CLASS V CONSTRUCTION
AND OPERATION CLEARANCE PERMIT
APPLICATION FORM.
 FEE $200 PER WELL
PART II
DEWATERING SITE
DEWATERING
 DEWATERING SHALL MEAN TO DISCHARGE OFF-
SITE OR ON-SITE WATER FROM AN EXCAVATION
DURING CONSTRUCTION OR EXISTING
STRUCTURE FOR MAINTENANCE AND REPAIR OF
UNDERGROUND UTILITIES
 DEWATERING CAN BE MADE BY WELL POINT
SYSTEM OR OPEN EXCAVATION PUMPING
DEWATERING METHODS
OPEN EXCAVATION
 OPEN DEWATERING SYSTEMS ENABLE ONE TO
LOWER THE GROUND WATER TABLE
ADEQUATELY IN COHESIVE LOW PERMEABLE
SOILS. WATER IS PUMPED OFF DIRECTLY FROM
SUMPS ALONG THE TOES OF THE SLOPES OF THE
EXCAVATION WORKS.
OPEN EXCAVATION DEWATERING
SYSTEM
DEWATERING METHODS
WELL-POINT SYSTEM
 WELL-POINT DEWATERING SYSTEMS ENABLE TO
LOWER THE GROUND WATER TABLE
ADEQUATELY FOR DEEP AND LARGE
CONSTRUCTION SITES.
 THIS DEWATERING SYSTEM IS USED IN ALL TYPES
OF GROUND WHICH ARE PERMEABLE.
WELL-POINT DEWATERING SYSTEM
DEWATERING POINT OF DISCHARGE
 OPEN EXCAVATION DEWATERING
HOLE TO HOLE DISCHARGE
2. DISCHARGE TO TEMPORARY OR PERMANENT
DRAINAGE SYSTEM(exfiltration trench, outfall, or
drainage well)
 WELL POINT SYSTEM
1. DISCHARGE TO TEMPORARY OR PERMANENT
DRAINAGE SYSTEM
2. DISCHARGE OFF SITE
1.
CALCULATION OF THE REQUIRED
DEWATERING
 OPEN HOLE DEWATERING
CONE OF INFLUENCE FROM DEWATERING
2. SETTLING VELOCITY IN SEDIMENTATION TANK
3. DISCHARGE CAPACITY OF EXFILTRATION
TRENCH OR DRAINAGE WELL
 WELL POINT SYSTEM
1. CONE OF INFLUENCE FROM DEWATERING
2. DISCHARGE CAPACITY OF DRAINAGE SYSTEM
1.
CONE OF INFLUENCE
THE USAGE OF STORMWATER
DRAINAGE WELL IN A DEWATERING
PROCESS
 STORMWATER INJECTION WELL IS USED FOR
TEMPORARY DEWATERING DISCHARGE DURING
CONSTRUCTION IN CASES WHERE OFF-SITE
DISCHARGE IS NOT ALLOWED OR SITE HAS
SHALLOW CONTAMINATION PLUME
MIAMI-DADE COUNTY DEWATERING
REQUIREMENTS TO DISPOSE INTO A
STORMWATER INJECTION WELL
 THE PROPOSED SITE IS NOT CONTAMINATED
 IF THE SITE IS CONTAMINATEDOR WITHIN 500 FEET
MUST OBTAIN POLLUTION REMEDIATION SECTION
APPROVAL.
 FDEP APPROVAL IS REQUIRED
 CALCULATION MUST DEMONSTRATE THAT THE
STORWATER INJECTION WELL IS CAPABLE TO
HANDLE THE DEWATERING DISCHARGE
 CALCULATIONS TO REDUCE TURBIDITY
DISCHARGE INTO THE WELL
WHY DO RER DERM AND FDEP
REGULATE STORM WATER WELL?
STORM WATER WELL IS A CONCERN BECAUSE
IT MAY CONTAIN THE FOLLOWING:
SEDIMENT
NUTRIENTS
METALS
MICROORGANISMS
FERTILIZERS
PESTICIDES
CONCLUSION
 MIAMI DADE COUNTY RER DERM AND FDEP
PERMITTING PROCESS TO DISPOSE OF STORM
WATER VIA INJECTION WELLS IS TO ASSURE THE
PROTECTION OF GROUNDWATER RESOURCE
FROM CONTAMINATION