Lengthy and costly delays may await those who do not have a plan
for lawful dewatering of their building sites.
Christchurch's prized water can cause headaches for the
excavations essential to the demolition, rebuilding and repair
works at the heart of the rebuild. Site dewatering can all too
easily breach environmental controls, causing unwelcome costs and
It is all too easy to cause problems unwittingly by intercepting
and removing or disposing of water in the wrong place or way,
especially as our rivers, streams and aquifers weave an intricate
and complex web through and under the city.
Building and demolition sites with excavations readily run the
risk of water being intercepted or collected and mixed with mud,
cement, oil from machinery or environmentally harmful demolition
materials. Such unsavoury cocktails can wreak havoc with the
quality of our water resources. Even if the water being discharged
is entirely clean, putting too much into small water bodies with
low capacity can add to the risk of flooding elsewhere. Important
springs or wells can be harmed if their source is intercepted by an
The RMA requires Environment Canterbury to control the risk of
this harm through consent requirements for the taking, diversion
and discharge of water, which will capture dewatering. The
resulting rules aim to strike a balance between protecting the
valuable water resources, while not imposing impractical and
Permitted activity rules allow some takes, diversions and
discharges for site dewatering without consent, but only if they
are unlikely to cause any harm to surface or groundwater. Very
specific limits and conditions apply, which are designed
specifically to avoid this harm;
Where the limits or conditions cannot be complied with, other
rules require resource consents, so that additional or more
specialised protective measures can be required through conditions.
If the dewatering is too harmful resource consent can be refused
altogether under these rules.
They are far from simple; there are four from two separate
regional plans that have to be complied with to avoid needing
resource consent. It is not a case of picking the easiest rule and
just complying with that either, but all conditions and terms of
all rules have to be complied with, from the easiest to the
toughest. The conditions impose many limits. For example, on the
rate at which water can be pumped, the permitted concentrations of
contaminants, the amount that groundwater is allowed to drop when
pumping, and the duration of the works (e.g. nine months). Also
included are minimum flow rates for streams or rivers into which
dewatering fluid is pumped.
If any limits or requirements are breached without resource
consent, that is an offence with a maximum fine of $600,000 for
companies and $300,000 or two years' imprisonment for
individuals. For minor incidents instant fines of $750 or $1000 per
day or incident are available.
What is more, ECan also has the power to serve abatement notices
requiring that the non-complying dewatering ceases. Breaching one
of those is a further offence likely to attract even stiffer fines.
You may find that the only way to comply is to get a resource
consent, which may require input from an expert planner,
hydrologist, ecologist or other type of environmental scientists.
These experts could be required to help demonstrate that your
dewatering meets the policy requirements also contained in the two
regional plans that apply. The application is not a rubber stamping
exercise and getting consent may take some time. With a site
filling up with water, work has to stop; resulting delays while
machinery sits idle are potentially far more costly than the
considerable available fines.
Since excavations typically intercept groundwater or collect
surface water runoff, having a plan for dewatering lawfully is
essential. Before the machinery or contractors are ordered, check
whether you can comply with ECan's rules, get the necessary
consents if you cannot and implement practical measures to ensure
you comply with the permitted activity or resource consent
Whatever the cost or inconvenience of that, it pales into
insignificance when compared to the potential cost of being held up
while you get the necessary cost or, or of being convicted and
fined for dewatering that breaches the RMA.
The content of this article is intended to provide a general
guide to the subject matter. Specialist advice should be sought
about your specific circumstances.
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