Q: Why do I need a Dewatering permit?
A Public Works Dewatering permit is required when the excavated waters of a construction site must be removed to work on the installation of utilities by a pumping system and when flushing water mains.
You need to obtain at least one dewatering permit. If you are pumping water due to a high water table, the State of Florida requires a Generic Permit for the Discharge of Produced Groundwater from any Non-Contaminated Site Activity. If you will be dewatering uncontaminated water and you want to pump the water to the public right-of-way, you will need a permit from the City of Miami Public Works. Depending on where the water goes, you may need permits from additional agencies, such as FDOT and the South Florida Water Management District. The NPDES Section can help you determine which dewatering permits you need.
Q: To which system can I dewater into?
You can onlydewater into a storm sewer positive system. A positive system is a solid pipe drainage system that has a point of discharge, like an outfall.
Q: Where I am not allowed to dewater?
You are not allowed to dewater into the following types of storm sewer systems: French drains, covered ditches and pump stations. No discharge is permitted into a sanitary sewer manhole. The flow of water being discharged in the storm sewer system must be regulated so that the system is never overloaded, flooding the street or creating a traffic hazard.
If your site is contaminated, contact DERM and FDEP. You cannot use this PW permit form and you cannot dewater to the public right-of-way.
Q: How long will it take to issue a permit?
The permit is issued five business days after a complete application has been received.
Q: If I’m dewatering into county or FDOT right-of-way do I need a permit from the city?
No, but if it is a joint system (i.e. if the county/FDOT drainage system is connected to the city system) you also need a permit from the city.
Q: Is the city permit conditional to another permit?
Yes, the city permit is conditional to a Class V Permit from Miami-Dade County DERM.
Q: Do I need a permit to dewater clean rainwater from an existing utility manhole?
No, a dewatering permit is not required to dewater clean rainwater from an existing utility manhole.
Q: What happens if it rains?
The rate of discharge must be reduced or stopped during rainstorms, of if trouble develops with the drainage system such as overloading.
Q: When do I call for an inspection?
The NPDES Section of the Public Works Department must be notified at least 24 hours in advanceof commencing with the discharging of clean water (<29 NTU) into the approved storm sewer system. Please call the NPDES section at (305) 416-1294 for an initial inspection. If the inspection fails, there is a $30 re-inspection fee.
Q: Do I need a final inspection?
Yes, upon conclusion of the dewatering permit process, the contractor shall contact the NPDES section at (305) 416-1294 for final inspection of the existing storm sewer system used for the dewatering operation. Failure to call in this inspection may result in the contractor being asked to clean the entire drainage system in the vicinity.
Q: What to avoid?
- The pump design must be proportional to the size of the sedimentation tank as calculated by the Engineer of Record.
- No silt or other debris can be discharge into the storm sewer system. All water entering the storm sewer system must be less than 29 NTU.
- No indigenous material adjacent to the inlets shall be allowed to be washed into our storm sewer system. If by accident or other means, the storm sewer system upon completion of your pumping, is noted to have excessive silt, sand or other debris caused by your operation, you will be required to clean all storm sewer lines in the vicinity to our satisfaction.
- Take all necessary precautions to prevent the generation of loud, unnecessary noise.
- Remember, the public shall be properly protected from the dewatering apparatus and at street crossings the equipment shall be placed in a manner to minimize the disruption of traffic.