Trusted Civil, Structural and Environmental Engineers in Wallsend

Have you ever wondered why we have to consider soakaways first, before any other discharge option ? Are you aware of the Hierarchy of Drainage? The Hierarchy of Drainage outlines the order in which surface water runoff should be managed. This is the preferred order: 1. Infiltration into the Ground: The highest priority is to allow surface water to infiltrate directly into the ground. This can be achieved through methods like soakaways, filter drains, and permeable surfaces. The ground’s suitability for infiltration is determined through tests like BRE Digest 365 Soakaway Tests. If the soil infiltration rate is sufficient, this method is preferred. 2. Surface Water Bodies: If infiltration isn’t feasible, the next step is to discharge runoff to a surface water body such as a river, stream, or lake. This helps maintain water quality and supports local ecosystems. 3. Surface Water Sewers and Drains: When neither infiltration nor direct discharge to a water body is possible, surface water can be directed to a surface water sewer, highway drain, or another drainage system. These systems collect and manage runoff, but they should be used as a last resort. 4. Combined Sewers: The lowest priority is to discharge surface water into a combined sewer, which also carries wastewater from buildings. This approach is less desirable due to the risk of overloading the sewer system during heavy rainfall events.