*Increased [[phosphorus]] concentration in runoff water, however this may be mitigated by the reduced runoff volume resulting in a lower loading overall *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. | *Increased [[phosphorus]] concentration in runoff water, however this may be mitigated by the reduced runoff volume resulting in a lower loading overall *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. |