Changes

<li>The lightweight material is more prone to wind erosion, and this should be accounted for in the initial design, alternatives include erosion control blankets, soil tackifiers, or Sedum mats.  </li>

<li>The lightweight material is more prone to wind erosion, and this should be accounted for in the initial design, alternatives include erosion control blankets, soil tackifiers, or Sedum mats.  </li>

</ol>

</ol>

Increasing the depth of planting medium from 100 mm to 150 mm has been shown to benefit the vegetation[http://www.sciencedirect.com/science/article/pii/S0301479713006051]. Stormwater retention was not improved with this increase in depth[http://ascelibrary.org/doi/abs/10.1061/(ASCE)HE.1943-5584.0001534]. </p>

Increasing the depth of planting medium from 10 cm to 15 cm has been shown to benefit the vegetation[http://www.sciencedirect.com/science/article/pii/S0301479713006051]. Stormwater retention was not improved with this increase in depth[http://ascelibrary.org/doi/abs/10.1061/(ASCE)HE.1943-5584.0001534]. </p>

<h4>Irrigation</h4>

<h4>Irrigation</h4>

<p>Regular irrigation has been shown to substantially reduce the stormwater capture benefit of an extensive green roof[http://ascelibrary.org/doi/abs/10.1061/(ASCE)HE.1943-5584.0001534].  One way to reduce the irrigation used on green roofs is through the use of electronic technologies. Responsive sensors that suppress irrigation after a rainstorm are routinely attached to green roofs to conserve water. Improvements can be made by instead using a 'soil' moisture sensor to trigger irrigation. State-of-the-art management systems now use predicted weather data to  prevent irrigation ahead of storm events[https://optirtc.com/products].   

<p>Regular irrigation has been shown to substantially reduce the stormwater capture benefit of an extensive green roof[http://ascelibrary.org/doi/abs/10.1061/(ASCE)HE.1943-5584.0001534].  One way to reduce the irrigation used on green roofs is through the use of electronic technologies. Responsive sensors that suppress irrigation after a rainstorm are routinely attached to green roofs to conserve water. Improvements can be made by instead using a 'soil' moisture sensor to trigger irrigation. State-of-the-art management systems now use predicted weather data to  prevent irrigation ahead of storm events[https://optirtc.com/products].   

<p>The choice of vegetation on an extensive green roof is insignificant in stormwater management compared to the choice of planting medium or the provision of irrigation. The vegetation should be selected to be resilient to both very wet and very dry periods. <em>Sedum</em> species are the most common choice, demonstrating excellent longevity in systems without irrigation. </p>

<p>The choice of vegetation on an extensive green roof is insignificant in stormwater management compared to the choice of planting medium or the provision of irrigation. The vegetation should be selected to be resilient to both very wet and very dry periods. <em>Sedum</em> species are the most common choice, demonstrating excellent longevity in systems without irrigation. </p>

<p> However, some projects expect the low growing <em>Sedum</em> to  remain in graphic designs according to species and flower color. This is not a realistic expectation without huge maintenance costs. Instead project stakeholders should be prepared early in the design process to embrace the green roof as a living and evolving ecosystem. </p>  

<p> However, some projects expect the low growing <em>Sedum</em> to  remain in graphic designs according to species and flower color. This is not a realistic expectation without huge maintenance costs. Instead project stakeholders should be prepared early in the design process to embrace the green roof as a living and evolving ecosystem. </p>  

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