<li>Daily irrigation can reduce the annual retention by 20% compared to a roof without irrigation. i.e. 40% for irrigated compared to 60% without irrigation[http://ascelibrary.org/doi/abs/10.1061/(ASCE)HE.1943-5584.0001534]. However, recirculating rainwater from a cistern was estimated to double the annual retention in Florida[http://www.mdpi.com/2073-4441/4/4/914]. The research team modeled 87% retention for a green roof coupled with a cistern, compared to 43% for the green roof alone. </li> | <li>Daily irrigation can reduce the annual retention by 20% compared to a roof without irrigation. i.e. 40% for irrigated compared to 60% without irrigation[http://ascelibrary.org/doi/abs/10.1061/(ASCE)HE.1943-5584.0001534]. However, recirculating rainwater from a cistern was estimated to double the annual retention in Florida[http://www.mdpi.com/2073-4441/4/4/914]. The research team modeled 87% retention for a green roof coupled with a cistern, compared to 43% for the green roof alone. </li> |