Getting dewatering consents right the first time
At a glance
Getting dewatering consents right the first time can save weeks of delay, reduce costs, and reduce environmental and commercial risk – yet too often, projects are tripped up by unclear expectations resulting in time and effort spent responding to requests for further information (RFIs) from the regulator.
New tools and guidance are now helping to change this by providing clearer direction, which can lead to a more consistent and efficient resource consent process.
Getting a dewatering resource consent approved has often been a tricky and frustrating process. It can take a lot of time and money, and if the application isn’t quite right, it usually means more requests for information, delays, and extra work. But it doesn’t have to be that way.
New tools and guidance developed for Canterbury now give applicants a much clearer idea of what’s needed to get it right from the start. While these resources were designed with Canterbury in mind, they provide solid baseline information and processes that can be useful for councils and regions across Aotearoa New Zealand. For consultants and contractors working nationwide, this guidance could really improve how dewatering impacts are assessed, documented and consented.
Why does it matter?
Having prepared and audited quite a few of these consents myself, I’ve seen firsthand how unclear guidance can create unnecessary risks – and a lot of frustration for everyone involved. Canterbury Regional Council pointed out that the quality of dewatering consent applications varied widely. Some were missing key information, while many assessments lacked the rigour or consistency councils needed to make decisions confidently, leading to requests for more detail. And when project timelines are tight, as they often are, even small delays in consenting can have a ripple effect on design, procurement, and delivery.
What does the guidance cover?
The new guidance provides a clear and methodical approach to assessing the effects of dewatering. It includes:
- Brief summary of existing national and international guidance documents
- Overview of dewatering methods and mitigations
- Guidance on project planning, using a risk-based approach, and recommendations for site investigation and monitoring
- Guidance on groundwater modelling, sensitivity and description of the spreadsheet-based tools
- Information on ground settlement modelling
- Recommendations on reporting
By following this guidance, applicants can provide councils with the information they need up front, minimising RFIs and smoothing the path to approval.
Even outside of Canterbury, the principles behind this approach are widely applicable. In fact, some councils may choose to adopt or adapt these resources as part of their own processes, especially in areas where dewatering is a common issue.
Clear guidance isn’t just paperwork. It’s the key to unlocking smoother projects and stronger environmental outcomes.”
Why collaboration matters
Dewatering assessments don’t sit in a silo. They often intersect with other disciplines and project stages – from environmental impact assessments and construction planning to stormwater management and infrastructure design.
Not having a clear understanding of dewatering rates and drawdown effects early on can lead to overly cautious design assumptions that drive up costs unnecessarily. Even worse, underestimating these effects could put ecological values or nearby assets - like buildings or wetlands - at risk. By bringing technical teams together sooner and using shared guidance as a common foundation, projects can run more smoothly and confidently, helping to reduce both commercial and environmental risks.
Why is this timely?
The New Zealand government is currently reforming the way resource consents are processed, with an aim to fast-track good development while improving environmental outcomes. There’s a growing focus on making applications simpler, more standardised, and more robust – particularly for infrastructure projects that are critical to housing and climate resilience.
We’re already seeing the effects of these changes across many of our client projects, and it's clear that better-quality applications will be increasingly important in this new environment.
The new dewatering guidance directly supports that goal. It provides both applicants and councils with a shared reference point, helping avoid inconsistent reviews and the resulting delays.
In the past, the lack of clear guidance meant everyone approached dewatering assessments differently – both in preparing applications and reviewing them. That inconsistency often led to unnecessary friction.
Now, with this new guidance, everyone has a clear process to follow. That not only makes things easier for consultants, applicants, and council staff – it helps the whole consenting system run more smoothly.
If you’re preparing or advising on a dewatering consent, this is a real opportunity to improve how we work – supporting better environmental protection, faster project delivery, and a much smoother journey through the regulatory maze.