R/CR-8

Strategic focus area:

Description:

This project will advance knowledge of tidal marsh ecosystems and their response to rising tides and increased flooding, and the effects of hydrologic restoration in marshes threatened by loss. We aim to develop a mechanistic understanding of restoration of interior dieback areas using shallow channels ("runnels") and create a general framework of practice. Co-PIs and partners are involved in several existing hydrologic restoration projects in MD, with others proposed, creating an urgent need for information to guide decision-making. Objectives include quantifying the effect of landscape-, marsh- and microhabitat-scale conditions on drainage, edaphic-condition restoration, and vegetation recovery. We will also identify characteristics of runnel design (e.g., runnel width and depth gradient, others) which correspond with successful recovery, test for changes to sediment fluxes, and produce protocols for practitioners. We expect to find hydrologic restoration is effective in a broad range of conditions. However, we expect restoration outcomes will be less successful with tidal amplitudes < 0.5 m, relative tidal elevations < 0.5 Z*, and with a more intensive history of ditching. We expect to find that increased flushing is as important as lowering the water table for restoration success, and that even after drainage edaphic factors can cause a lag in vegetation recovery. By identifying limitations, we can improve design of hydrologic restoration projects. With a project team including scientists, practitioners, and engagement specialists, we will co-produce knowledge that supports healthy coastal ecosystems, and resilient communities and economies. Primary end-users include restoration practitioners included as Co-PIs, and landowners of coastal marsh property requiring hydrologic restoration in Maryland. Ultimately, this project will result in enhanced understanding of tidal marsh vulnerability and resilience, a "restoration toolkit" brochure for landowners, at least two new landowner agreements for new restoration projects, a how-to manual for practitioners, peer-reviewed articles, and scientific and public presentations.