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What to Consider When Building in Flood Areas

Are you looking to develop on an untapped plot of land that can get flooded at times? Before you go ahead, find out why building in floodplains is trickier than you may think.

As a developer, you can overcome many difficulties and build something durable in the harshest of terrains. And developing in areas that can get flooded are among them.

But in such an area, the threat of flooding is not the only thing that should worry you. The fact is that building in a flood zone can further increase the risk of flooding.

Why does that happen?

It’s because development affects the soil and water flow.

For example, you have to replace the soil with impervious surfaces. This interference causes more water to accumulate in nearby streams and rivers.

You’re essentially increasing the average flow rate year-round as a result. It can become particularly dangerous in the flood seasons if the water can’t seep into the ground as it did before.

It can also interfere with the natural passage of floodwaters, potentially diverting them to the buildings.

That’s why developing in known flood areas requires extra attention to detail. You have to take care of a few safety considerations before you get to the planning and building stages.

Safety Considerations

Factor #1. Frequency of Flooding

One of the easiest ways to determine if you are working in a flood area is to look at the data.

How often does rainfall cause overflow in nearby streams or rivers?

How often do people evacuate the area every year?

All of this tells you how risky it is to build there. It also gives you an idea of the feasibility. Ask yourself:

Would people want to buy a home in an area prone to flooding?

Factor #2. Isolation

How isolated is the land that you want to build on?

How far away is it from critical services like hospitals, fire stations, etc.?

The property’s location is everything, especially for development in flood areas.

The reason for this is quite simple:

Long and sustained flooding cuts off access for many who live there.

It isolates the residents from family members and can prevent them from going to work. It can also make it difficult for anyone to get medical care or even food and essentials.

Not to mention that electricity, sewage, and drinking water may become unavailable for a while. None of these scenarios is likely to attract buyers and tenants.

Factor #3. Depth and Velocity

You have to understand the depth and velocity of floods in the area. This means knowing if the site gets shallow water or slow-moving water. Also, you have to determine if the water is very deep or fast-flowing.

All of this information is critical to building structures that can handle the risks. This information is vital to not only building requirements and materials, but it also affects people’s safety out on the streets.

If the floods tend to create deep and fast-moving waters, it’s not a safe environment for anyone. Residents can injure themselves from just trying to divert water from their homes or going to work.

Factor #4. Vulnerability

Does the flooding risk pose an immediate threat to certain people?

If you think about it, not everyone can tackle a flood equally well.

The Australian Rainfall and Runoff national guidelines consider some people very vulnerable, regardless of the flow regime and flooding frequency. These include young kids, the physically and mentally incapacitated, and the elderly.

That means that you also have to consider how your development will affect future residents. Whether it’s to offer them a safer living environment or to minimise the building’s impact on the soil.

Getting Building and Planning Permits

For most forms of development, you have to get either a planning or a building permit, or both. And understanding the differences between the two can save you some time.

A planning permit allows you to develop or use a land lot. In contrast, you need a building permit to actually build on the land.

And for flood areas, it’s essential to have both. The same applies when you want to develop in a waterway.

To get your permit, you usually go to the local council. But the approval will depend on the regional planning schemes.

For example, a council will have to account for a variety of factors when evaluating a permit application. It takes into account local and state planning policies. And it also looks at the overlay and purpose of the proposed area for development.

Lastly, the planning scheme accounts for the degree of flood hazard in the area. It also looks at the requirements to minimise said hazard. This could include methods of construction, land management, and more.

And it ties back to what’s discussed at the beginning of this article – constructing in a floodplain can negatively impact the environment. It can contribute to an increase in flooding frequency and damage.

So, you have to carry out a thorough assessment of the land and the flood provisions. Obtaining permits for developing on this type of land takes longer because of the additional guidelines and policies.

Plan Every Detail for Safe Development and Approval

Flood areas are some of the most difficult to develop on as there are so many variables to account for.

It requires the right permits and a thorough feasibility study. You also have to account for the potential risks, impact on the soil, and many more. And the environmental hazard is a problem before you even lay the foundation.

How you approach this type of project will affect the safety of what you build and those around it during a flood. You want to find out beforehand if the risk is worth the reward.

This is precisely what Archistar can help you with.

Use the platform to understand everything about a potential development site. Take advantage of the Due Diligence reports and Nearmap data to identify the right project.

Schedule your demo to learn more.