Approach
Natural systems can be used in place of gray infrastructure in some cases to help address changing precipitation patterns and resulting hydrological shifts. Forested riparian areas serve several important ecosystem functions, including reducing soil erosion, buffering high flows, regulating base flows, moderating stream temperatures, reducing evaporation from surface waters, and providing migration corridors for wildlife and plant species. Forest floors with porous soil that are rich in organic matter capture, absorb, and slowly release water to groundwater and downstream sources, providing critical regulation of water quality and quantity, including the attenuation of flood flows. Floodplain systems reduce the magnitude of flood events by physically slowing water velocity as it overtops channel banks. Restoration of stream channel form and function can enhance bank stability during and after large storm events and helps reduce risks of erosion, channel instability, and degradation of aquatic habitat. In some areas, ponds created behind beaver dams can help stabilize the water table, reducing run-off and sedimentation from large storm events and storing water on the landscape. Beaver dams can also maintain or improve the quality of fish habitat, especially during low-flow periods. All of these nature-based solutions can be harnessed individually or in tandem in the vicinity of recreational infrastructure to enhance an area’s ability to accommodate changes in peak and low flows.
Tactics
- Maintain buffered riparian corridors with vegetation that can withstand and regulate flooding events.
- Plant or maintain ecosystem-appropriate shrubs and trees in riparian corridors to minimize erosion, overland flows, and run-off, and to provide shade that would help offset anticipated increases in water temperature.
- Increase soil organic matter through retention of biomass or addition of soil amendments in order to enhance soil-water infiltration and increase the water-holding capacity of the soil.
- Improve channel sinuosity of waterways by removing man-made 'hard measures' within floodplains, and increase stream-floodplain connectivity.
- Use stream-restoration techniques (e.g. cross vanes, j-hooks, or other grade-control structures) in order to dissipate stream energy associated with high-energy stream flows and extreme precipitation events.
- Promote and/or reintroduce beavers into strategic drainages where their presence would not negatively impact recreational or other infrastructure.
- Maintain beaver dam ponds to stabilize the water table, reduce run-off and sedimentation from large storm events, and store water on the landscape.
Strategy
Strategy Text
Projected changes in precipitation and temperature are expected to alter hydrologic regimes through changes in streamflow, snowpack, evapotranspiration, soil moisture, surface runoff, infiltration, flooding, and drought. Many of the roads, trails, campgrounds, and other infrastructures that support recreational activities were constructed in a manner that restricted stream-channel flow and reduced floodplain connectivity, among other hydrologic alterations, which today has produced an inability to adequately accommodate higher peak flows and flooding, especially during extreme precipitation events. Damage to roads, trails, campgrounds, and other infrastructure brings with it the potential of damage to natural resources, especially where impervious or below-grade surfaces concentrate water into flow pathways, generating high-velocity runoff and erosion of soils. This strategy describes options to prepare for uncharacteristic hydrologic events in order to reduce the extent or severity of damage to both recreational infrastructure and adjacent natural resources. It is important to keep in mind that modifications to maintain hydrology at one site may have negative impacts on hydrology at another site.
O’Toole, D.; Brandt, L.A.; Janowiak, M.K.; Schmitt, K.M.; Shannon, P.D.; Leopold, P.R.; Handler, S.D.; Ontl, T.A.; Swanston, C.W. Climate Change Adaptation Strategies and Approaches for Outdoor Recreation. Sustainability 2019, 11, 7030.