Promoting living shorelines for shoreline protection: understanding potential impacts to and ecosystem trade-offs with adjacent submersed aquatic vegetation (SAV)
Abstract
As is the case for many estuaries and coastal embayments, shorelines around Chesapeake Bay (CB) are rapidly eroding, with even more rapid erosion expected in the future due to human and environmental changes, such as urbanization and accelerated relative sea-level rise (RSLR) rates. Shoreline erosion not only increases sediment input into adjacent waters, degrading water quality, but also results in property loss. In response, many property owners seek to protect their shorelines with stabilization structures. Recent efforts have focused on "green" infrastructure, including living shorelines (LS) - narrow marsh fringes with or without additional structures. LS are encouraged by legislation in many states, including Maryland (MD), and provide similar ecosystem services as natural marshes (e.g. sediment and nutrient retention, wave attenuation). But, questions remain regarding LS resilience to environmental change, especially in regions like CB where relatively rapid rates of RSLR and declining sediment supplies have led to widespread marsh loss. Questions also remain regarding the potential long-term impacts of LS to adjacent SAV, which are keystone species in CB. While LS installation may disrupt local SAV and even replace SAV immediately against the shoreline with marsh plants, it could benefit offshore SAV through trapping land-derived sediments and preventing them from clouding adjacent waters, thereby increasing water clarity and the depth at which SAV can grow. On the other hand, if the LS, like many Chesapeake marshes, does not keep up with sea-level rise and drowns over time, it could become a sediment source to adjacent waters, reducing light reaching the bottom and shrinking potential SAV habitat. LS and SAV beds provide many similar ecosystem benefits, but direct comparisons of sediment and nutrient burial, as well as reduction of shoreline erosion, are scant. This presentation addresses these questions through field observations in the subtidal and intertidal of several 10-y-old LS, with the ultimate goal of helping inform management decisions on permitting LS in areas with SAV.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFMOS21A..06P
- Keywords:
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- 4217 Coastal processes;
- OCEANOGRAPHY: GENERALDE: 4235 Estuarine processes;
- OCEANOGRAPHY: GENERALDE: 4262 Ocean observing systems;
- OCEANOGRAPHY: GENERALDE: 4299 General or miscellaneous;
- OCEANOGRAPHY: GENERAL