In a previous GES Newsletter we provided an in-depth look into groundwater discharge permitting for construction dewatering projects (  As a follow up, we will explore some of the ways to remain in compliance with your NPDES discharge permit and why it’s so important to maintain compliance for the duration of your project.

As a way of background regarding permit compliance, the Nevada Division of Environmental Protections (NDEP) Bureau of Water pollution Control (BWPC) is responsible for inspecting 100% of NPDES major dischargers and 20% of minor dischargers annually as set forth in EPA’s National Program Managers Guidance for the NPDES Compliance and Enforcement Program agreements between NDEP and EPA Region 9 (“Agency Agreement on Compliance and Enforcement” and “Memorandum of Understanding for NPDES Compliance and Permitting Activities”).

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Groundwater being discharged to a settling tank

As such, there is no guarantee your project site will be inspected and despite living in Las Vegas, it’s best not to gamble on permit compliance.  If you have received one of the various categories of NPDES discharge permits, here are some ways to maintain compliance:

  • First and foremost, read and understand all the provisions of your permit.  The Enforcement Branch of the BWPC (responsible for NPDES review and compliance and enforcement activities related to NPDES) has stated a significant portion of compliance issues can be directly related to permittees not fully understanding the obligations set forth in their permit.
  • Stormwater and groundwater don’t mix!  For example, if your NPDES discharge permit covers construction dewatering activities and your point of discharge is a storm drain drop inlet with an inline settling tank between the two, stormwater runoff after a rain event may contaminate an open excavation so it’s a good idea not to collect compliance samples immediately following a rain event.
  • Ensure you remain at or below your permitted discharge rate.
  • Never create a “bypass” which is the intentional diversion of water from any portion of a control measure, such as a flowmeter or sampling port.
  • “Nuisance Water” vs. “Groundwater”.  This is an interesting one and always subject to multiple interpretations.  Let’s look at an example.  Say
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    Outfall flowrate monitoring

    you have a pipeline construction project that requires dewatering.  The contractor installs dewatering wells, pumps groundwater to a settling tank, collects monthly compliance samples and discharges the water from the settling tank to a storm drain drop inlet.   However, during trenching activities, the contractor encounters groundwater.  The contractor uses a sump pump to remove the groundwater and discharges it directly to the storm drain.  The source of the water is the same – groundwater but one is removed from a well and the other from an open excavation.  Oddly enough, the water removed via sump pump from an open excavation (even though its groundwater) is classified as “nuisance water” and does not fall under the provisions of your NPDES permit and is considered Allowable DeMinimis Discharge.  However, if you comingle the two groundwater sources (i.e., through a manifold pipe system) then this action would be non-compliant.

Maintaining compliance is important for several reasons:

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Groundwater from an open excavation being pumped and discharged to a temporary settling pond

1st – you want to avoid costly fines and project delays due to temporary project shutdowns (this can also bring negative press to your project).

2nd – staying in compliance is good for the environment and helps ensure minimal impact to our precious groundwater resources.

3rd – The BWPC is responsible for entering information about its NPDES permitting, compliance and enforcement program in EPA’s national database (ICIS-NPDES). If you are found to be out of compliance you may be issued a Findings of Violation Order or a Notice of Noncompliance.   Either way, you don’t want your project to end up on a state or federal environmental database with noncompliance or violation issues.

If you are in need of groundwater discharge permitting support or you would like GES to present information about dewatering groundwater discharge permitting, give GES a call.

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Groundwater being discharged to a settling tank

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Construction dewatering activities

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Dewatering wells manifolded to a single discharge line