Borehole Soakaways
Soakaways are usually the preferred means for draining away surface water collected from roofs and roads etc. These are usually shallow gravel-filled trenches, modular crates systems, or perforated concrete rings. However, sometimes shallow ground conditions are not favourable for these shallow systems, and an option can be a deep borehole soakaway. In layman's terms, these are almost like a dry well, usually with a concrete ring storage chamber at the top to store a sufficient volume of water.
The depth of the borehole is typically between 10m and 20m. The depth and number of boreholes will depend on a number of factors including:
- The volume of water to be discharged and the rate of flow
- The ground conditions and the primary/secondary permeability
- The groundwater table (soakaways do not work below the water table!)
- The size of the concrete storage rings
- The number of boreholes to be used
- Borehole specifications (diameter, filter pack, slotted section, slot sizes)
