Approach
Areas downstream from infrastructure that concentrate or divert water flow are vulnerable to flooding, erosion, and impaired water quality as more frequent and intense precipitation events occur. Therefore, design approaches that use natural materials (e.g., soils and plants) and that enable the landscape to distribute water rather than concentrate it may minimize impacts on vulnerable downstream sites and enhance groundwater recharge.
Tactics
- Use an ecological approach when designing built environments, using green infrastructure and low impact development techniques in watershed activities to keep water onsite and protect water quality using natural features.
- In coastal and riparian settings, evaluate the use of vegetation and soil-based systems to provide shoreline stabilization and erosion protection, rather than hard armoring such as concrete. In river and stream settings, soil bioengineering may be appropriate.
- Where an engineering analysis indicates that some level of armoring or structural protection is necessary to protect structures, utilize ecologically-friendly materials and surfaces.
- For wetland restoration project design, consider grading concepts that spread out water and lower hydraulic energy, rather than concentrate it.
- Improve drainage, stabilize slopes, and restore vegetation ground cover adjacent to impervious surfaces to slow runoff, deposit sediments, and reduce erosion potential.
Strategy
Strategy Text
This strategy addresses adapting infrastructure designs and maintenance to support wetland ecosystems under changing environmental conditions, including infrastructure found within or near wetland watersheds such as bridges, culverts, stream crossings, roads, trails, parking lots, utilities, coastal structures, docks, and piers. Roads, stream crossings, recreational trails, facilities, and other infrastructure are known to affect local landforms and hydrology, particularly where impervious surfaces concentrate water into flow pathways, generating high-velocity runoff and erosion. For this reason, critical evaluation of past design concepts and criteria with additional consideration for a changing climate and altered hydrology may be necessary to minimize risks and safety concerns over the designed lifespan of the unit. A changing climate challenges traditional perceptions of “low maintenance” infrastructure that can be built and left unattended, and heightens the necessity of increased infrastructure monitoring, inspection and routine maintenance. Contemporary philosophies for wetland management, enhancement and restoration have shifted toward the minimization of traditional infrastructure in the watershed, and incorporating natural or low impact development to dissipate excess water can both reduce negative downstream impacts and reduce the need for hard infrastructure. However, changing environmental conditions also merit renewed consideration of infrastructure designs that recognize changing conditions to support wetland function and watershed management.