National Soakage Design Guide Draft – Open for Feedback
Tim Strang
Tim is a Principal Engineer at Wellington Water, working within the Design Team. Tim has had 25 years covering a variety of roles across consultancy and local authority organisations. Tim has worked on soakage designs regularly throughout his career, including developing many of the design charts that are still used in the current GD07 design manual.
Matt Packard
Matt is an Associated Geotechnical Engineer, CMEngNZ (CPEng), based in Tauranga currently working for ENGEO Limited.
Matt has over 24 years professional consultancy experience. He is responsible for leading key projects and providing technical advice.
Matt has an extensive range of geotechnical experience, specialising in large public and private infrastructure projects, slope stability, compressible soils, liquefaction, lateral spreading, and the design of complex temporary and permanent stormwater and retaining structures.
Mike Trigger
Mike is the Environmental and Infrastructure Manager at BCD Group, and a practising geotechnical engineer with extensive experience in stormwater management, on-site disposal systems and land development across New Zealand. Mike first became interested in soakage design practices when working as a development engineer for a council with a number or underperforming soakage devices in vested assets.
He works closely with councils, developers and geotechnical specialists to address complex soakage and infiltration challenges, particularly in areas with variable soils, groundwater constraints and intensifying development pressures. Mike has been actively involved in national discussions on improving soak pit testing and design methodologies, with a focus on hydraulic performance, long-term reliability and alignment between consenting frameworks. He brings a practical, evidence-based approach that combines field experience with a strong understanding of regulatory and hydrological principles.
Bodo Hellberg
Bodo is an Infrastructure Standards Specialist at Tauranga City Council and a civil engineer with more than 20 years’ experience in stormwater, drainage and water resources engineering across Germany and New Zealand.
He leads the development and maintenance of the Infrastructure Development Code (IDC) and has authored and co-authored key national and regional stormwater guidelines, including GD01. His work spans hydrological modelling, infrastructure design, consent assessment and compliance, and technical standards development, with a strong focus on practical implementation.
Bodo has extensive experience in soakage and infiltration design, testing methodologies and regulatory alignment. He works closely with councils, consultants and industry to address challenges associated with variable soil conditions, groundwater constraints and increasing urban intensification. His approach combines field experience, modelling expertise and standards development to improve reliability, clarity and long-term performance of soakage systems.
He is an active contributor to national stormwater working groups and regularly presents at industry conferences and training events.