Understanding The Importance Of Flood Risk Assessments And Topographical Surveys

Flooding presents a major threat to property, infrastructure, and the environment. With climate change having an increasing impact on weather patterns and thereby increasing the likelihood of flooding, early intervention becomes a key factor. Two great tools in the risk management armoury are Flood Risk Assessments and Topographic Surveys. These aid in providing information to property developers, owners, and businesses alike about land use and construction activities.

What is Flood Risk Assessment?

Flood Risk Assessment (FRA) assesses the risk of flooding in a specific area. This is generally mandated as part of the planning application process so that any development will not worsen flood risk to the site or to areas beyond the site. This assessment will broadly take into account previous flooding, precipitation, drainage conditions, and closeness to water bodies.

The benefits of undertaking an FRA are:

·       Set flood-risk zones before project planning

·       Assist in planning drainage and flood protection

·       Comply with planning and environmental law

·       Lower financial and structural risk to property owners

 

The Role of Topographical Surveys in Flood Risk Management

Topographical surveys are thorough surveys specifying what natural and man-made features are on a land area. They map out elevations, slopes, and surface drainage patterns, all of which are very useful in the flood risk assessment process.

In undertaking a topographical survey, an engineer or planner will:

·       Understand surface water drainage over the site

·       Identify potential blockage points

·       Determine ways to avoid flooding through the creation of flood measures and SuDS

·       Calculate actual costs incurred due to flood risk.

Combining Both Assessments for Effective Flood Mitigation

Flood Risk Assessment, coupled with Topographical Surveying, gives a full understanding of the flood risk on a site. Using combined data from both means that a developer can take on effective flood mitigation, such as better drainage systems and more flood-resistant building techniques.

In general, putting up these assessments not only makes one's development or purchase long-term sustainable but also meets required regulations. The fact that weather patterns have become so unpredictable makes it imperative to take proactive measures through such assessments.

When You Need and When You Don’t Need Flood Risk Assessments?

Flood risk assessments help owners and engineers understand whether their site lies in a flood risk zone and take measures to minimise the risk of flooding. If you want to start a project in an area that is in a flood zone, is a flood risk area, or is located within 20 meters of a river, you will need an FRA report to get planning permission.

Topographical surveys are performed on the proposed development site to prepare the FRA report. You are required to submit the report along with your planning proposal. But you may not need this report at a number of times.

 

This blog talks about the occasions when you will need and when you will not need flood risk assessments—

 

When You Need FRAs

 

·       If the area of your construction site is 1 hectare or more, then you will need to submit the FRA report to get approval for your project planning.

·       If the area is smaller, but the development site is located in Flood Zone 2 or 3

·       If the site is smaller than 1 hectare and is in Flood Zone 1, and there is a change of use proposed.

·       If the development area is smaller than 1 hectare and is in Flood Zone 1, there is a risk of flooding not because of the river or sea but because of on-site water drain systems.

 

When You Don’t Need FRAs

 

·       If the development area is smaller than 1 hectare and is in Flood Zone 1.

 

Before FRA, you might need a sequential test that steers development to land areas or zones with the lowest flood risk. It is required for major and minor developments that are in Flood Zones 2 and 3 or are in Flood Zone 1 with a possibility of flooding during their lifetime.

 

However, for a detailed report, you will need to hire a professional for topographical surveys of your land area or proposed construction site.

 

5 Reasons You Need Topographical Surveys

Topographical surveys are detailed, 3-dimensional maps of a land or property. They are also known as topographical surveys or informal reports.

Ideally conducted by highly experienced structural engineers, these maps highlight various features and aspects of a piece of land or property, such as the location of a plot of land and its size.

In this blog, we discuss some of the reasons why and occasions when you will need to hire structural engineers for topographical surveys for land or property surveys.

1.             To Measure the Size of Your Property or Plot of Land.

If you have to take the measurement of your estate for some legal purpose, such as to obtain approval for construction, you will need a legally prepared and documented topo survey report.

2.             To Ensure the Suitability of Land for Further Construction.

If you are planning to start some construction project on your property, a topographic survey helps ascertain whether or not it is suitable for any new development or the kind of construction you are planning on.

3.             To Check the Land Height Difference.

Topographic surveys are comprehensive reports that describe the height of different parts of a property. This way, the report will help you with waterway and drainage planning.

4.             To Determine the Legal Boundary of Your Property.

Property disputes are among the most common legal battles. Getting your property surveyed by qualified structural engineers will help determine the legal boundary of land or property, present legal documents during such disputes, and lower the chances of such disputes in the first place.

5.             To Ensure the Accuracy of Your Project.

No builder or owner wants their development to have structural flaws and constructional inaccuracies. Topographical surveys help the developers use materials of the right strength, follow the right approach, and apply the right technique to carry out the construction.

In addition to these, topographical surveys are useful when creating irrigation channels in a land area. Government agencies and privately owned tourist spots consider these surveys to double-check the safety of crowded areas.