One of the issues that comes with urbanisation in heavily populated areas, is Stormwater and Stormwater Management. Stormwater is water that occurs as a result of precipitation, but can also be associated with melting snow. When stormwater is not absorbed by the ground, it is known as surface runoff.

Stormwater is an issue in urban areas, because of the amount of development in terms of building work and man-made structures and surfaces. Due to the nature of the materials used in this construction process, water tends not to be able to soak away into the ground as concrete and tarmac tend to be impermeable.

This results in the need for drainage and sewers, which need to be carefully managed and maintained in order to prevent these overflowing at times of heavy rain. Stormwater management also involves the taking of preventative and precautionary measures to avoid pollution or flooding damage from stormwater and excess surface runoff.

Stormwater has a number of potential negative effects on the environment. It can cause erosion to natural waterways, transfer pollutants into the water system and the rivers and in the worst cases cases it can cause damage by flooding. Therefore it is now a vital part of the design process to take the potential risks of stormwater into account when undertaking any urban planning.

There are a number of methods of implementing preventative stormwater management. One method is the use of underground stormwater tanks; such as those currently being designed in Swindon. These are large underground vessels which will capture 1000m3 and 500 m3 of stormwater between them. These are being built due to large amounts of continued urbanisation in the area, which results in the need for preventative measures to be taken to avoid any potential flooding.

Other methods that can be used include the use of retention ponds, which trap water and gradually release it into the water system, rather than it all making its way there at once, thus easing the risk of flooding. On a small scale, the use of rain gardens (planted areas in a depression near a source of runoff) can be used to ease the issue of excess stormwater and also do so in an aesthetically pleasing fashion.

The use of soakaways, is another potential method for combating the negative effects of excessive stormwater. These are submerged structures that take in water through gravity and in a similar fashion to a retention pond, gradually release the excess water into the water system.

In terms of urban planning and design, it is important for those involved in the process to take into account the dangers involved with stormwater. When precautionary measures are taken, as is the case in Swindon, then dangers involved with flooding should be avoided, in comparison to a situation in Germany, the Czech Republic and Hungary for instance where not enough precautions were taken and flooding occurred.