This page contains resources applicable to dewatering operations in the design phase. The tools below can be used when evaluating dewatering systems suitable for the project and applicable permits for those situations. Coverage under Appendix G, Hawaii’s National Pollutant Discharge Elimination System (NPDES) General Permit Authorizing Discharges Associated with Construction Activity Dewatering is mandatory for all projects with dewatering effluent that will be discharged to a surface water body or a storm drain that leads to one. See the Construction Dewatering Tools page for dewatering resources pertaining to the construction phase.
Selecting a Dewatering Operation
The guide to the right features a flow chart and considerations for determining which dewatering system will be most feasible for the project, including options that will not require NPDES permit coverage for dewatering. It also highlights information that should be passed on to the Contractor.
Applying for Coverage under the NPDES Dewatering Permit
If dewatering to a surface water body or a storm drain that leads to one, the project will need coverage under either Appendix G, the NPDES General Permit Authorizing Discharges Associated with Construction Activity Dewatering or an NPDES Individual Permit. Applying for the permit will typically start in the design phase in order to allow time for processing, but the permit itself will ultimately be handed off to the Contractor as his/her responsibility.
Below are two options for NPDES permit coverage. Click on the links below for instructions from the State of Hawaii Department of Health, Clean Water Branch:
- Notice of Intent – for requesting coverage under the current Appendix G NPDES General Permit (Expires Jul. 2022).
- NOI Form G must be included in the NOI application
- A complete NOI should be submitted no later than 30 days before the proposed starting date of the discharge or 30 days before the expiration date of the applicable Notice of General Permit Coverage.
- If a partially completed NOI will be submitted (e.g., when a contractor has not been selected yet), the missing information will still need to be submitted 30 days prior to the commencement of discharging.
- Individual Permit – for requesting coverage under an independent permit specific to the needs of your project
- NPDES Form G must be included in the individual application
Note: There are other forms that must be submitted according to the discharge/activity that coverage is being requested for (e.g. Form C must be submitted for projects with a disturbed area equal to or greater than 1 acre). Click here for the list of forms. If applying for two or more discharges/activities, separate NOIs must be submitted for each. Alternatively, multiple discharges/activities may be combined under one individual permit.