Stormwater, Flood and Civil Engineering

Approval-ready designs and documentation for DA, CDC, CC and OC developments across Sydney and NSW.

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Chartered Professional Engineer (CPEng) | National Registered Professional Engineer (NER) | Registered Design Practitioner — Civil & Drainage | Qualifed Builder

What we do

Stormwater

Stormwater management plans, on-site detention, water sensitive urban design, stormwater diversions and drianage easements. The drainage design set councils ask for at DA, CDC and CC.

Stormwater services→

Flood

Flood modelling in TUFLOW and HEC-RAS, flood risk assessment, hydrology and catchment analysis. Run in-house, not subcontracted. '

Flood services →

Civil

Road and pavement design, driveway and vehicle access, Roads Act approvals, earthworks, erosion and sediment control.

Civil services →

Certification

Occupation certificate sign-off, works-as-executed review and Class 2 regulated design declarations — including on projects designed by others.

Certification services →

Expert Witness

Independent expert reports, peer review and Land and Environment Court evidence in stormwater, drainage and flood matters.

Expert witness →

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Who we work with

Architect, designers and developers Icon
Builders and contractors Icon
Homeowner Icon
Solicitor Icon

Homeowners

Clearing council stormwater and flood conditions so you can start.

Solicitors

Independent engineering evidence in drainage and flood disputes

Builders and contractors

Buildable documentation and someone who answers the phone during construction.

Architects, designers and developers

Design collaboration that clears DA, CDC, CC and OC without surprises.

Recent work

Case Studies | Stormwater, Flood & Civil Projects NSW
OSD reduced by 30% — Dual Occupancy, Northern Beaches
OSD reduced by 30% — Dual Occupancy, Northern Beaches

Northern Beaches Council · Dual occupancy ·

Council's charts called for more detention than the site could hold. Site-specific DRAINS modelling cut the required volume by 30%. Approved.

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Expert Witness & Custom OSD — Warehouse, Willoughby
Expert Witness & Custom OSD — Warehouse, Willoughby

Willoughby City Council · Industrial ·

Tight headroom, discharge and water quality targets unmet, and a matter heading to conciliation. A custom two-chamber tank and expert evidence settled it. Approved.

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Four-Lot Subdivision Drainage — Northern Beaches
Four-Lot Subdivision Drainage — Northern Beaches

Northern Beaches Council · Subdivision

Four lots all needing gravity drainage, almost no room for detention, and the neighbour's kerb sitting on private land. Approved.

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Stormwater & OSD on a heritage site — commercial building, Ku-ring-gai
Stormwater & OSD on a heritage site — commercial building, Ku-ring-gai

Ku-ring-gai Ku-ring-gai Council · Commercial

A heritage cottage, a partially low-lying site and almost no headroom for a tank. The answer was two drainage systems rather than one. Approved.

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Overland Flow Assessment — Single Dwelling, Mosman
Overland Flow Assessment — Single Dwelling, Mosman

Mosman Council · Alterations & additions

The site sits low in its catchment and floods in large storms. The question was whether street-level extensions could be built at all. Approved.

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Flood Risk Assessment — Commercial Shopfront, Northern Beaches
Flood Risk Assessment — Commercial Shopfront, Northern Beaches

Northern Beaches Council · Commercial

The client wanted to lower the floor level on flood-affected land. Council's own flood controls contradicted each other. We had it resolved. Approved.

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Water Quality & Detention — Bus Depot, Singleton
Water Quality & Detention — Bus Depot, Singleton

Singleton Council · Industrial ·

Water quality treatment and on-site detention delivered without a single tank. The parking area does the storing.

Approved.

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Road Widening & Stormwater — 10 Multi-Dwelling Homes, Lake Macquarie
Road Widening & Stormwater — 10 Multi-Dwelling Homes, Lake Macquarie

Lake Macquarie City Council · Multi-Dwelling

Council required a road widening but wouldn't say how far it extended — and part of the existing road sat on private land. Approved.

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Driveway & Access Design — Commercial, Central Coast
Driveway & Access Design — Commercial, Central Coast

Central Coast Council · Commercial

Ten parking spaces on a site that barely fits them — and grades steep enough to drain without vehicles bottoming out on the way in. Approved.

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Vehicle Access on a Regional Road — Alterations, Ku-ring-gai
Vehicle Access on a Regional Road — Alterations, Ku-ring-gai

Ku-ring-gai Council · Alterations & additions

A regional road frontage demands a turning bay. A narrow site leaves nowhere to put one. B85 modelling found the smallest that worked. Approved.

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Change of Use — Stormwater, Flood & Public Domain, Inner West
Change of Use — Stormwater, Flood & Public Domain, Inner West

Inner West Council · Change of use

Wall-to-wall boundaries with nowhere to run pipes, a basement surrounded by floodwater, and a driveway that had to become a footpath. Approved.

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Why Amuna

Principal-led

Every design is prepared or reviewed by a Chartered Professional Engineer.

Buildable

Our principal is also a qualified builder — designs arrive resolved for construction, not just compliant on paper.

Registered

We prepare regulated designs and compliance declarations under the DBP Act.

Fast

Typical turnaround 2–4 weeks, and we deal with council engineers directly.

  • "Fantastic experience with Stuart and Richard from start to finish on a complex job pushing the boundaries of stormwater and driveway design. Their communication throughout was excellent, and their documentation thorough. I highly recommend them and will use them again."

    —Scott, Orraarchitecture

  • "We have had the pleasure of collaborating with Amuna Civil Engineers on numerous projects, and their professionalism and expertise consistently impress us. Stuart and his team bring a level of efficiency, accuracy, and problem-solving that makes our job as architects significantly smoother. Their clear communication, attention to detail, and proactive approach ensure that challenges are addressed swiftly and effectively. Beyond their technical capabilities, the team at Amuna is always pleasant and easy to work with. We highly recommend them to anyone seeking reliable and skilled civil engineers."

    —Annie, Playoust Churcher Architects

  • "Dealing with Stuart at Amuna is always a great experience. MGP have been working with Stuart for a number of years, his stormwater management and civil engineering design solutions are effective, efficient and compliant. He is always available to answer questions and makes the whole process seamless. Highly recommended."

    —Alex, MGP - Building & Infrastructure Services

Modelling and Software

We hold licences for the software that councils expect, our own engineers run the models

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Qgis Software Logo
Autodesk Software Logo
Autodesk Civil 3D Software Logo
Hec Ras Software Logo
Tuflow Software Logo
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Areas we service

Working across Sydney, the Central Coast, the South Coast and regional NSW — including but not limited to the following Councils:

Hunters Hill, Lane Cove, Ryde, Willoughby, North Sydney, Inner West, City of Sydney, Ku-ring-gai, Northern Beaches, Waverley, Woollahra and Randwick.

Start your project with us today

Send us your site address and plans.

We'll come back with a fixed fee, usually within one business day.

Stuart@amuna.com.au | 0410 992 700

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