Approach
Enhancing water storage and slowing the physical movement of water across the landscape increases the residence time of water, providing sources of water for plant transpiration, soil-water and plant-water storage, and seepage to groundwater. Water retained in forested systems is typically high-quality, clean, cold water that is slowly released throughout the year, a process likely to become even more important to managers seeking to sustain water quality and yield as the climate warms and seasonal precipitation becomes more variable. Climate changes to the hydrologic cycle are expected to challenge the capacity of forests to sustain delivery of water throughout the growing season and in dry periods ; and also challenge forested systems’ capacity to buffer and attenuate flood flows during more frequent extreme events. Critical watershed recharge and storage areas include headwaters, vernal pools, transitional areas, riparian and bottomlands, floodplains, leaf litter and porous soils. Planning to avoid or minimize disturbances in these areas may help to maintain the mechanisms that capture, absorb, and store water as land-use and climate continue to change.
Tactics
- Thin forests to reduce stocking densities, and perform shorter harvest cycles to reduce interception and transpiration and increase water retention in forested systems.
- Restore in-stream complexity by adding meanders, depressions and scour pools using natural stream channel classification, and restoration techniques to increase water retention in-channel.
- Apply soil amendments such as wood ash or biochar that boost water-holding capacity, soil productivity and carbon storage.
- Re-engineer or design roads and infrastructure to discharge runoff into natural areas and hillslopes slopes to increase water capture, reduce water losses and minimize runoff velocities.
- Use contour felling techniques, mulching with tree branches and fertilization to enhance retention of soil-water for deeply rooted trees.
- Disable drain tile, plug or fill lateral ditches and/or construct low-head berms in drained wetlands adjacent to main ditches that cannot be disabled to retain drainage upstream in the watershed.
Strategy
Strategy Text
This strategy aims to help ecosystems adjust in response to fundamental changes in hydrologic processes altered by a changing climate. The timing, form, and spatial distribution of precipitation is changing with the climate, with cascading effects on forest hydrologic cycles that affect water yield and water quality. Forest species assemblage, structure, and habitat quality will shift with changes in the nature and timing of water availability. Anticipating potential impacts to water levels and quality in management planning may help managers reduce risks and take advantage of opportunities to sustain hydrologic function. Broadly considering climate related alterations to the hydrologic cycle along with site-level responses and potential land-use changes is likely to provide the most complete picture of risks and opportunities.
Shannon, P.D.; Swanston, C.W.; Janowiak, M.K.; Handler, S.D.; Schmitt, K.M.; Brandt, L.A.; Butler-Leopold, P.R.; Ontl, T.A. (in review). Adaptation Strategies and Approaches for Forested Watersheds. Ecological Applications.