Civil Engineers near you

Performance Requirement H2P1 sets two outcomes. Surface water from a storm having a five per cent annual exceedance probability must be disposed of in a way that avoids the likelihood of damage or nuisance to any other property, and surface water from a storm having a one per cent annual exceedance probability must not enter the building. The deemed-to-satisfy provision, H2D2, is met by drainage designed and constructed to AS/NZS 3500.3, or to the ABCB Housing Provisions Part 3.3 for roof drainage where rainfall intensity does not exceed 255 millimetres per hour at the five per cent annual exceedance probability.

Both, and they control different things. The Code sets the performance outcome and the deemed-to-satisfy path. The council controls the legal point of discharge, which is where you are permitted to send the water, along with crossover standards, any detention requirement and sediment control conditions. Because the point of discharge is the constraint the whole design hangs off, confirm it with the council first. A stormwater plan drawn before anyone checked where the water may lawfully go is usually a plan that gets redrawn.

It depends on how much impervious area you are adding and where the water currently goes. Paving converts ground that absorbed and slowed water into a surface that sheds it, and the low point of most suburban sites is a boundary. The Code requires surface water from the five per cent storm to be disposed of without causing damage or nuisance to any other property, so if the extra runoff will reach a neighbour, it needs to be caught and taken to a lawful discharge point. On a small, flat, well-drained site the answer may be a simple grated drain; on a sloping one it rarely is.

It is the route water takes across the site once the pipes are full, which is exactly what happens in the rarer of the two design storms. The Code requires that surface water from a one per cent annual exceedance probability storm must not enter the building, and no reasonably sized pipe network handles that event on its own. The flow path is designed with levels: finished floor heights, the fall of paths and driveways, and a deliberate route to the street. It is also the thing most often destroyed later by a new fence, a raised garden bed or a retaining wall across it.

It depends on the state, and it works the same way it does for structural engineers. Victoria lists civil engineering among the five prescribed areas of engineering under the Professional Engineers Registration Act 2019, alongside fire safety, structural, electrical and mechanical engineering, with mandatory registration phased in between 2021 and 2023 and an offence for providing professional engineering services unregistered. Other states approach it differently, and some regulate only work on particular building classes, so check your own state's arrangements rather than assuming a national scheme.

Because both requirements in the Code are decided by levels, not by plan dimensions. Whether water leaves your site without becoming a nuisance next door, and whether the rarer storm can enter the building, come down to millimetres of fall across a driveway, a threshold or a side path. A contour and detail survey gives the engineer the existing levels, the structures, the trees and the services to design around. Without it, any drainage plan is an assumption about the ground drawn at a desk.