Many sewer systems in the UK can no longer cope with the surge of rainfall and flooding events and with many urban areas increasingly used for housing and commercial projects, below ground water management systems that can be built upon meaning there is no loss of land take are becoming more valuable.
SuDS or Sustainable Drainage Systems that take into account water quality, quantity and climate change look to control the flow rate of surface water run-off, the storage and collection and treatment of below ground water systems.
In April this year, a new code for sewers adoption came into effect, which included SuDS assets for the first time, with water companies taking ownership and responsibility for sustainable drainage systems. Introduced in 2014, as one of the main measures to control and mitigate flooding through the Government’s National Planning Policy Framework (NPPF), SuDS looks at natural waterways to control, manage and store surface water runoff.
SuDs should ease the pressure on the drainage network and attenuation tanks have been included in the new guidance for the first time. Where land is scarce, stormwater attenuations solutions such as an underground tank system can be installed using a precast concrete flatpack system, box culverts or large diameter pipes.
Below ground, precast water management systems can be used in unsuitable ground conditions, such as high water tables or areas where the soil can be a hazard. The weather can also pose a risk as some systems can be subject to floatation, the heavy nature of concrete means it does not float. Some engineered systems can also be badly affected by bright sunlight and hot weather during installation, whilst this may not happen often in the UK, it is happening more and more due to climate change.
According to an English Housing Survey (2014/5) over 75% of the 23.4 million homes in England are over 40 years old, over 56% are over 55 years old and more than a fifth of occupied houses are over 100 years old. Precast concrete pipeline systems have a design life of over 100 years so can easy match the service life required by the housing market.