A recent expansion of Hospice of Wake County in the town of Cary, NC utilized numerous environmentally-conscious features including a storm water conservation system that will recycle rain water and air conditioner condensation.
A 50,000 gallon cistern, buried under an originally permitted detention pond, is an innovative design for sustainability as it is designed to capture, treat, and re-use rainwater for irrigation to the grounds and gardens at the Hospice.
The cistern is constructed of modular blocks called “raintanks” and are capable of handling an H-20 vehicle load. The filter media over the tanks is ESCS lightweight aggregate fines that allow the rain water to pass through and treat the storm water at a rate higher than traditional bio-retention media. The system will greatly reduce runoff
volumes and reduce water consumption for irrigation. The system will be set to maintain the infiltrate (rain water) holding level at least eight inches below surface grade for grass viability.