Hydrogeology & Hydrology
Groundwater and surface water expertise for councils, infrastructure partners and industry, backed by decades of technical depth.
Understanding What’s Happening Below and Around the Water Table
Water moves through aquifers within the ground in ways that aren’t always obvious, and getting that picture right is often what determines whether a project, a consent application or a resource decision holds up. Earthtech has built one of the country’s most established hydrogeology teams, working across every stage of a project from preliminary planning and groundwater investigation through to modelling, assessment of environmental effects and consenting.
Our scope runs from groundwater takes for irrigation and municipal supply through to construction and quarry dewatering, and contamination fate and transport. With the recent rise in shallow geothermal energy, we’ve also developed specific expertise in geothermal groundwater takes for heating and cooling applications, applying the same rigour we bring to municipal supply and irrigation work.
Hydrology is a newer part of our practice, and one we’ve built deliberately. We monitor and assess surface water flow regimes to define environmental flow limits and abstraction availability, giving councils, infrastructure partners and large landowners the technical basis they need to plan water use with confidence.
Applications & Services
Our team manages projects across the full groundwater and surface water spectrum, from monitoring and pump testing through to availability assessments, dewatering and contamination fate and transport. Investigations are designed and managed to suit the scale of the question, whether it concerns a single bore or a regional aquifer.
Investigation & Design Expertise
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Borehole and screen design -
Surface water investigations, including stream flow monitoring via gauging and weir installation
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Groundwater investigations, including pump testing design and interpretation
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Groundwater and surface water quality sampling and interpretation
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Simple local-scale to complex regional-scale groundwater aquifer and surface water catchment availability, management and sustainability studies
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Geothermal groundwater take feasibility studies and consenting
Consenting, Compliance & Expert Evidence
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Assessments of Environmental Effects to support resource consent applications and ensure regulatory compliance
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Drafting of groundwater and surface water management plans, including incorporation into conditions of consent and operational/life-cycle maintenance plans
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Conceptual and numerical groundwater modelling using industry-recognised software including FEFLOW, Leapfrog 3D, Seep/W and AQTESOLV
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Interpretation of project and asset requirements under the Auckland Unitary Plan, National Environmental Standards, and other regional and national legislation
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Expert witness work for resource consent hearings
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Technical peer review
Field Investigation Expertise
Every investigation is scaled to the question being asked, from a single bore test to monitoring programmes running over a full irrigation season. Our field capability includes:
Pump Testing
Water Quality Sampling
Weir Monitoring
Stream Gauging
Modelling Depth Backed by Fieldwork
Few teams carry this breadth of software and field capability under one roof. We move between FEFLOW, Leapfrog 3D, Seep/W and AQTESOLV as the project demands, backed by hands-on aquifer testing, borehole design, and stream gauging experience that keeps our modelling grounded in what’s actually happening on site. That means fewer handoffs, fewer gaps between field data and final conclusions, and a consent application that reflects real conditions rather than a desktop assumption.
“We found the entire team at Earthtech to be highly professional throughout the process. Their expertise and guidance have been invaluable in helping us plan for the long-term water security of our property.
We would have no hesitation in recommending Earthtech Consulting Ltd for similar projects.”
Andy Wood – Golf Course Manager
Kauri Cliffs Golf Maintenance
Our Hydrogeology & Hydrology Projects
Pukekohe Municipal Water Supply
Project Summary Recommissioning of the Pukekohe municipal supply which abstracted water from Hickey's Spring and two deep Kaawa aquifer bores. Services Provided Conceptual and numerical groundwater modelling of effects for 1,509,000m³/yr take for Watercare from three production bores. Quantitative streamflow analysis to determine flow available for abstraction and low flow requirements in the Whangapouri Stream, including statistical analysis of low flow recurrence intervals. Preparation of Assessment of Environmental Effects (AEE). Project Conclusion Successful consenting of the water take consent as part of Watercare's response to the 2020 drought conditions.
Franklin Deep Waitemata Aquifer Groundwater Availability Study
Project Summary Deriving the groundwater abstraction availability for the Franklin Deep Waitemata Aquifer in accordance with the Auckland Unitary Plan. Services Provided Development of a conceptual model for the aquifer; including groundwater flow paths, recharge and discharge zones, and aquifer boundaries. Review of existing management area boundaries. Calculation of groundwater availability for each management area. Project Conclusion The successful determination of aquifer abstraction availabilities for four separate groundwater management areas.
Ngaakooroa Stream Bridge Dewatering
Project Summary Elevated artesian groundwater pressures coupled with overhead power lines, created challenging conditions for bridge pile construction. Working with the project team, Earthtech provided a dewatering bore design solution to depressurise the artesian groundwater levels. Timeframes were very tight, meaning that the dewatering design, consenting and dewatering bore construction stages significantly overlapped. The project was delivered on time, and Earthtech assisted with real-time groundwater level control and monitoring during piling activities. Services Provided Groundwater analysis and design of a bore-field dewatering system. Preparation of the Assessment of Environmental Effects and consenting of the groundwater take (dewatering) and diversion activities. Ongoing involvement and contractor support during dewatering and piling activities, including assisting with the setup of groundwater level alert and…
Collins Road Wastewater Facility Dewatering
Project Summary Earthtech became involved in the project when unexpected groundwater conditions and piping in the excavation floor were encountered during construction of 7.8m to 9.1m deep excavations and shafts for wastewater infrastructure construction. We carried out groundwater investigations and pump testing to define a dewatering solution that provided a dry, safe and stable excavation during the 6-month construction dewatering period. Earthtech's involvement continued during construction, with the management of pumping rates and monitoring to ensure that neighbouring properties and infrastructure were protected from dewatering effects. Services Provided Groundwater investigations and pump testing. Groundwater analysis and design of a bore-field dewatering system. Preparation of Assessment of Environmental Effects and consenting of the groundwater take (dewatering) and diversion activities. Preparation of…
Talk to Our Hydrogeology & Hydrology Team
Whether you’re scoping an investigation, working through a consenting process or need a second opinion on a groundwater model, you’ll be dealing directly with the specialist who understands the full picture. No call centres, no account managers standing between you and the answer.
