Overland Flow

Is your property subject to overland flow flooding? Are you required to know what level of overland flow is on your property for either certification or approval? At Civil and Water Design we can define the level, extent and speed of overland flow for you with the right civil engineering certification.

So what is it and why do you need to know about it?

Typically it results from high intensity rainfall such as a summer storm. The rainfall hits the ground and other surfaces and finds a flow path. This flow path eventually leads to a waterway or drain. These are called overland flow paths and can cause overland flow flooding. Depending on the lay out of the land some of these paths can be relatively large with fast flowing water. It is these larger, faster-flowing, flow paths that can cause sediment, rubbish and other debris to be transported during a storm. It is also these overland flow paths that can cause flash flooding in areas such as yards and roads during storms.

Why do we need to know about it? Firstly, it is good to know where they are located for safety during storms so you know where to avoid and where flooding may occur during such an event. It is also helpful to know about significant overland flow paths so as to reduce damage of property through design and prevention.

Secondly, if you are constructing a building on your property, undertaking significant renovation, subdividing or developing you will need to have the level, extent and speed of the overland flow on your property defined. Works will need to be designed accordingly. For those projects requiring building certification or Council approval this will need to be defined by a registered, certified engineer.

For overland flow we offer a service for a variety of purposes and levels. These include:
  • Overland flow assessments for building certifications;
  • Overland flow reports for small developments;
  • Overland flow flooding reports for developments;
  • Overland flow flood impact assessments; and
  • Overland flow flood risk assessments;