A project team is deciding on the impact of a proposed concrete walkway.

Adding a concrete walkway will increase the site’s impervious cover, which is the percentage of the site area that does not allow water to infiltrate into the ground1. Impervious cover can affect the site’s stormwater management, heat island effect, and habitat quality.The project team should consider using permeable paving materials, vegetated roofs, or rain gardens to reduce the impervious cover and mitigate its impacts2. The other options are not directly impacted by adding a concrete walkway.Project density calculations are based on the floor area ratio and the number of occupants, not the site features3.Erosion and sediment control plan during construction is required for any site disturbance, regardless of the type of material used4.Air quality as a result of off gassing that occurs as concrete cures is not a significant issue for outdoor applications, and can be minimized by using low-emitting concrete products5.