Monday, 19 September 2011

Sustainable Drainage Systems (SuDS) and the Flood and Water Management Act 2010 - Are you ready for the changes?

Following the disastrous flooding of 2007 the government investigated the root causes of the flooding. But are you ready for the resulting legislation?

Traditional thinking was that water runoff naturally ran into natural drainage ways, into streams, rivers, when the volume got too much the rivers would overflow and cause flooding. Our drainage infrastructure would lead urban runoff away from sites and delay its entry into river courses, hence reducing the volume of water that might cause fluvial flooding. The investigation of the Pitt Committee actually concluded that the root cause was actually our drainage infrastructure itself.

Sustainable Drainage Systems include a range of architectural and planning features, such as a green roof.
Photo: Charlie Vinz, Creative Commons, FLIKR
We had become so reliant on being able to channel runoff into our inbuilt drainage network that it was simply unable to cope. Linked to climate change which has meant that sudden heavy downpours have become more common and you have a recipe for disaster. If you add in that the massive influx of water often contained runoff pollutants then the situation becomes even more severe. 

In response to this the government introduced the Flood and Water Management Act 2010. Two key recommendations were included: 
  1. Local Authorities or Lead Local Flood Authorities were created to take emphasis away from the drainage basin approach to flood management as adopted by the Environment Agency. In effect localising flood control efforts. 
  2. The right to automatically connect a new development to the existing Sewer and Drainage infrastructure was removed. Instead a new development or redevelopment project will first have to submit a Sustainable Urban Drainage Plan to the SuDS Approval Body (SAB) prior to gaining planning permission. 
Flood Control has become local. The legislation has received Royal Assent and Industry standards and regulations are being finalised, the objective being that the Act will be fully implemented and enforceable by March 2012. 

What are Sustainable Drainage Systems (SuDS)?

For those who have been fortunate enough to travel to many parts of the world, say Florida or Texas, you may have asked yourself why is there so much water around lying in ponds or swampy areas? Why don’t they drain it away and reduce the number of mosquitoes? These are examples of Sustainable Drainage Systems (SuDS), also known as Sustainable Urban Drainage Systems (SUDS). Simply put, control rainfall onsite and minimise the runoff of this water into the drainage system. There are many ways that this achieved by for example retention ponds, roof attenuation, swales, seepage areas or even grey water recycling, such as storing it for future use. 

All of these methods need to be considered by developers or land purchasers, or their consultants when planning projects. Each of the Lead Local Flood Agencies will set a quota for the amount of water that is allowed to drain off your property and enter the public water system. Anything above this is your problem to deal with inside your local SuDS design.

Decisions, Decisions...

All SuDS plans submitted for approval to the SAB will have to have the following characteristics:
  1. Pollution Control 
  2. Flood Prevention 
  3. Biodiversity and Wildlife Benefit 
Environmental, geological, hydrogeological and contaminated land issues become critical to the evaluation of the type of SuDS system that can be employed on a site. Alongside the cost benefit analysis the above are crucial factors. Certain SuDS methodologies simply will never be approved in certain instances. 

Bearing in mind all the above factors it is critical that when designing a SuDS system that full and comprehensive analysis is made of geological, geotechnical and environmental factors.

FIND Maps is able to assist organisations by providing rapid viewing, printing and export capabilities for all of the relevant datasets. Our EnviroFIND service allows you unlimited, intelligent viewing of EA and certain BGS data sets for as little as £ 25 per month. Additionally, we have a range of products which will be coming out over the next few months to assist in your SuDS project planning.

Links to map and data layers useful for determining SuDS plans:

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