<p>A 'closed loop' system can be created by coupling a rainwater harvesting system to a green roof. by catching and reusing runoff, the only water leaving the system is through evapotranspiration. This prevents any runoff from leaving the site and so prevents any nutrient loading to the environment. </p> | <p>A 'closed loop' system can be created by coupling a rainwater harvesting system to a green roof. by catching and reusing runoff, the only water leaving the system is through evapotranspiration. This prevents any runoff from leaving the site and so prevents any nutrient loading to the environment. </p> |