A National Pollutant Discharge Elimination System (NPDES)/State Disposal System (SDS) permit will be needed to cover waters associated with hydrostatic testing of new pipeline and buoyancy control. Hydrostatic testing is done to check the structural integrity of new pipelines. Buoyancy control water is used to temporarily maintain the pipe in place during installation.
Testing the structural integrity of pipelines involves filling the vessel with water to a desired pressure and then checking for leaks or fissures. Buoyancy control involves filling the pipeline segment with water and capping it so that the segment of pipeline stays in place during the installation process. Test and buoyancy control water is normally secured from a nearby water body, groundwater or a municipal supply.
Upon completion of the test and buoyancy control, the process wastewaters must be discharged. It is this discharge that the NPDES/SDS permit addresses. Enbridge must discharge in accordance with NPDES/SDS permit conditions which can include monitoring, limits, and best management practices. The amount of water to be discharged is predicated upon the length of pipeline segment being tested or installed and can vary between several thousand gallons to several million gallons. Discharge duration can last from one day to several days depending about the amount of water to be discharged and discharge velocity.
The MPCA follows the general process below for processing water quality permit applications. Steps in green indicate opportunities for public participation in the process.
The public comment period for the draft water quality permit for Enbridge Energy’s Line 3 project closed on April 10, 2020. The MPCA reviewed all comments and information received and has finalized responses to comments and the final permit. The final permit is effective November 12, 2020.
- Final NPDES-SDS Permit Cover Letter - Line 3
- Final NPDES-SDS Permit - Line 3
- Final NPDES-SDS - Infiltration Plan - Line 3
- Final NPDES-SDS Findings of Fact - Line 3
- Final NPDES-SDS Findings of Fact - Contested Case Hearing Requests - Line 3
- Final NPDES-SDS Response to Comments - Line 3
Draft permit documents
- Draft Line 3 NPDES/SDS Permit (wq-wwprm1-55a)
- Draft Line 3 NPDES/SDS Fact Sheet (wq-wwprm1-55b)
- View public comments submitted for the draft industrial wastewater discharge permit
Industrial wastewater NPDES/SDS application
- Cover letter to MPCA - Nov. 25, 2019 (wq-wwprm1-53a)
- NPDES/SDS Transmittal Form (11-25-19) (wq-wwprm1-53b)
- Permit checklist (wq-wwprm1-53g)
- Industrial Surface Water Discharge of Process Wastewater Application (wq-wwprm1-53c)
- Industrial Land Discharge of Process Wastewater Application (wq-wwprm1-53d)
- Individual NPDES/SDS Permit Supplement (wq-wwprm1-53e)
- Environmental Protection Plan (wq-wwprm1-53f)
- Industrial chemical additives attachment form (wq-wwprm1-53h)
- Permit Application 10-26-2020 Infiltration Plan Amended
- Permit Application 10-26-2020 Supplemental Info Amended
- Cover letter to MPCA - Oct. 30, 2018 (wq-wwprm1-52a)
- NPDES Permit Application Checklist (wq-wwprm1-52b)
- NPDES Transmittal Form (wq-wwprm1-52c)
- Industrial Surface Water Discharge of Process Wastewater Application (wq-wwprm1-52d)
- Industrial Land Discharge of Process Wastewater Application (wq-wwprm1-52e)
- Individual NPDES/SDS permit application supplemental information (wq-wwprm1-52f)