The Reliable SuDS Compliant Choice

An Insight Into How X-Grid Can Help Your Project Stay SuDS Compliant

What is SuDS?

Sustainable Drainage Systems (or Sustainable Urban Drainage Systems) are primarily methods of reducing the amount of surface water ending up in the existing sewer drain networks, with the aim of reducing the risk of localised flooding and complementing the traditional methods of water management. An added bonus to a SuDS compliant water management scheme which uses an infiltration method is that the water runoff is cleaned as it permeates through several layers, removing pollutants and particulates.

There are several different types and categories which fall under the SuDS banner, including source control (paving), attenuation systems, infiltration systems, swales, ponds and green roofs. This range of solutions which can work either singularly or together as part of a wider networked system are most commonly seen around extra-urban areas, although their purpose might not always be obvious. Swales and ponds can be constructed in conjunction with permeable paving surfaces to help direct and contain large volumes of water following heavy rainfall.

These open water storage areas can help to promote biodiversity, with animals and insects capitalising on the natural flourish which accompany lush greenery and filtered water. We will examine more closely the different systems later in this post.

Localised flooding in 2007

Image showing a SuDS Drainage Pond

Why are SuDS Needed?

– Construction on any project that has drainage implications cannot begin until scheme is approved inline with National Standards for sustainable drainage by the SuDS approval body (SAB) (upper tier local authorities).
– Upon approval and delivery the SAB will then adopt and maintain SuDS that serve more than one property.
– There will also no longer be an automatic right of connection (Section 106 of the Water Industry Act).
Flood & Water Management Act 2010: Schedule 3

There are several key drivers for SuDS but they basically fall into two main categories: regulatory and environmental. In 2010, the Flood and Water Management Act received royal assent, creating a clearer responsibility with local authorities taking the lead for delivering flood risk management in their respective region. Climate change is another main contributory factor as predictions suggest that there will be a greater variability in weather as a whole, with extreme events increasing in both severity and frequency. It has been suggested that there will be warmer summers and wetter winters, which signals an increase in likelihood of greater runoff. There is additional concern over urban creep and the reduction of permeable land which is being replaced with roads, homes and car parks, so to future-proof our housing developments, we must take action now to ensure resilience against adverse weather in a changing climate.

Types of SuDS Solutions

Soft Landscaped SuDS Solutions

SuDS solutions come in many different forms, with the aim of catering for almost any application. Soft landscaping solutions tend to include:

Linear wetlands which provide conveyance to larger wetlands downstream, during which the water is treated and filtered naturally through biological means. The potential for storage and vegetation provides an opportunity to naturally break down pollutants collected during periods of rainfall, improving the quality of the water locally.
Swales are a shallow channel which are filled with vegetation which collects runoff from highways and pavements, providing conveyance to other parts of wider SuDS solutions such as detention ponds. SuDS solutions are becoming increasingly used in schools as they can provide a rich biodiverse environment for children to study and can be used as an interactive part of the curriculum.
Wetland ponds are used to store large amounts of water and are often used in conjunction with other elements of SuDS such as the two mentioned previously, which feed runoff into ponds for storage and long-term infiltration. These wetland ponds can help to improve the biodiversity of an area and offer animals and plant life a natural habitat in which to flourish.

Planted Brick Swale SuDS Solution

Green Roof SuDS Solution

Types of SuDS Solutions

Hard Landscaped SuDS Solutions

SuDS solutions can also come in the form of an engineered or hard landscaped form. Below are examples to name a few, others include rainwater harvesting, geocellular storage, fin drains etc.

Permeable paving is the practice of using paving products which allow rainwater and runoff to permeate through the surface, dealing with the water at the source. Below permeable paving systems tend to be soakaways created from low-fines hardcore such as MoT type 3, helping to increase the infiltration rate when compared to pre-existing sub-bases. These permeable paving solutions can be found in a huge range of applications such as car parks, footpaths, domestic driveways and are used to replace traditional concrete or tarmac surfaces. Permeable paving tends to come in the form of ground reinforcement grids, such as X-Grid, open course tarmac, permeable block paving or resin bound gravel.
Green roofs are primarily as close to the source as SuDS solutions can get and by covering a roof with vegetation or another medium helps to reduce the amount of runoff before even reaching ground level. The effectiveness of a green or living roof will depend on the thickness of the substrate on the roof. These can be constructed using X-Grid to retain the soil and maintain the natural drainage routes while giving the soil structure and strength, preventing soil-loss. This type of solution provides attenuation, biodiversity enhancement and thermal cooling.

X-Grid and SuDS

How can X-Grid be used in SuDS?

Boasting huge versatility, X-Grid can be used in several ways to help create both individual SuDS elements and as part of a wider system. For example, on a new supermarket construction project, X-Grid could be specified in several areas of the build, such as a green roof, with X-Grid being used to provide strength and stability to soil and prevents washout. X-Grid could also be used to create a gravel car parking surface which is practically zero maintenance, yet highly permeable. Locking gravel within the confines of the asymmetric cells of the X-Grid, it prevents migration and removes the need for regular raking due to rutting and gathering of gravel.

With X-Grid being a 94% open structure, this allows for as much water to pass through the grid as possible relatively unimpeded. It has a high loading capacity and can withstand upto 420 tonnes per square metre in compression before the cell walls will deflect. The inert nature of the grid makes it environmentally friendly to use and does not leech harmful substances into the ground around it. Its weatherproof nature and resistance to UV sunlight makes it a fantastic all-round choice to use in any climate and it has an operating temperature range of -50°C to +90°C, more than adequate for installation in any setting.

X-Grid for SuDS to reduce flood risk
Blog Author: Guy Wall
Blog Category: Uncategorised
Date Published: April 11th, 2017