20230124T151020230124T1640America/ChicagoDedicated Session: Western Shore of Mobile Bay: Restoration, Conservation, and Park InitiativesRoom 201B2023 Bays and Bayous Symposiummbnep@mobilebaynep.com
Relax, Reconnect, Restore: City of Mobile Park Improvements and Access Enhancements along Mobile Bay 03:25 PM - 03:40 PM (America/Chicago) 2023/01/24 21:25:00 UTC - 2023/01/24 21:40:00 UTC
Through an interconnected parks and trails system, the City of Mobile is improving access to Mobile Bay through several efforts. With the purchase of the Brookley properties through several funding sources, the City is master planning to create an iconic, nature-based park to allow for ADA accessible waterfront access and educational opportunities. Near Dog River, on Perch Creek, the City has purchased 90 acres of natural areas to conserve one of the last undeveloped tributaries of the River and to eventually provide nature-based walking trails and kayaking opportunities. By working with ALDOT to raise the Perch Creek Bridge, further water access into these natural areas has been enhanced. Along the Bay in this same area, improvements to McNally Park and the re-use of the historic Ziebach Property, will allow for improved bay front access for the Dauphin Island Parkway communities. The City has made extensive outreach efforts to meet the needs of these communities and continue to improve nature-based and bay front access.
Deer River Coastal Marsh Restoration 03:40 PM - 03:55 PM (America/Chicago) 2023/01/24 21:40:00 UTC - 2023/01/24 21:55:00 UTC
Located within the Deer River Watershed, the Deer River marsh system, one of the largest intact marsh complexes on the western shore of Mobile Bay, has long suffered from the impacts of winds, tides, wakes, and storm surge. Protecting this approximately 275-acre tract of salt marsh is a priority recommendation of the Western Shore Watershed Management Plan. With funding from the National Fish and Wildlife Foundation Gulf Environmental Benefit Fund and National Coastal Resilience Fund restoration activities are underway. Objectives of the project include: Stabilize and enhance up to 5,600 linear feet of shoreline; Reestablish the network of tidal channels, including the South and Middle Forks of Deer River, which are extremely shallow and impaired by siltation, limiting tidal exchange and circulation necessary to sustain the currently healthy marsh; Create up to 30 acres of additional marsh. Not without challenges, the project is currently in final design and permitting. The marsh-protection concept consists of an offshore constructed marsh island (3,000' long by 300' wide) with a segmented breakwater on its outer face. The marsh island will make beneficial use of 200,000 cubic yards of dredge material from the Mobile Harbor Channel deepening and widening project. As part of the Deer River hydrology enhancement approximately 50,000 cubic yards of soft organic material will be dredged from the channel, improving tidal flow and aquatic habitat. Thin-layer placement of this material will increase marsh elevations for approximately 50 acres, improving resiliency to storms and sea-level rise.
Characterizing Wave Climate to Inform Shoreline Protection Design 03:55 PM - 04:10 PM (America/Chicago) 2023/01/24 21:55:00 UTC - 2023/01/24 22:10:00 UTC
Just north of the mouth of East Fowl River, the Salt Aire marsh has experienced about 415 feet of shoreline erosion since the 1930s. The Salt Aire Shoreline Restoration Project aims to restore and stabilize approximately 30 acres of intertidal marsh habitat. The wave climate impacting the project site is the governing input in the shoreline protection design. In order to characterize the wave climate, Moffatt & Nichol performed a regional modeling effort using the Mike21 FM Spectral Wave model. The regional model was forced using wind and water level data hindcast over 34 years under low-intermediate sea level rise projections. The model was calibrated using two measured data sources: one offshore in deeper water and one nearshore in shallower water. The results of the modeling effort were statistically evaluated to determine water level, significant wave height, and peak wave period corresponding to different environmental conditions (percent exceedance and return period events). These results were used to calculate wave transmission through shoreline protection features for varying geometries, resulting in a risk-cost matrix for the project owner to use as a decision-making tool. This presentation will discuss means and methods utilized in the numerical modeling effort, summarize the wave climate at the project site, and describe the risk-cost matrix that resulted from the wave characterization.
Engineering with Nature to Restore Marsh Habitat on Fowl River 04:10 PM - 04:25 PM (America/Chicago) 2023/01/24 22:10:00 UTC - 2023/01/24 22:25:00 UTC
A team of scientists and coastal engineers is developing a solution to stabilize and protect priority in-river wetland spits and restore marshland throughout the intertidal portions of lower Fowl River. This NFWF funded project is being implemented through a collaborative effort between the MBNEP, ADCNR, and Mobile County to restore these important coastal spits and wetlands that were identified as a significant priority action in the Fowl River Watershed Management Plan. This presentation will discuss how the project team built upon the Fowl River Marsh study to identify shoreline restoration locations and develop engineering and construction design plans to stabilize and enhance priority coastal spits and shorelines of Fowl River from negative impacts associated with sea level rise, increased salinity, and boat wakes. The team will discuss the challenges associated with site conditions and permitting this complex coastal restoration project and the innovative engineering-with-nature approach to stabilizing shorelines and restoring marsh habitat. Through a phased and adaptive approach, the design solution will incorporate thin-layer placement of sediment on the spits and limit the extent of structural wave attenuation. Installation of rip rap sills and timber wave screen structures will be limited to the areas of greatest concern for overtopping and closest proximity to the river channel. An adaptive management plan will be incorporated in the final design to determine the timing for additional thin-layer placement of sediment and additional timber wave screen structures in the areas where they are most warranted.
Restoring and Enhancing Habitat and Access along the Dauphin Island Causeway 04:25 PM - 04:40 PM (America/Chicago) 2023/01/24 22:25:00 UTC - 2023/01/24 22:40:00 UTC
The Dauphin Island Causeway serves many purposes both as a corridor and access destination, but also has extensive adjacent marsh and oyster habitat. Mobile County has been working to restore these habitats and address safe managed access along this corridor. The Dauphin Island Shoreline Restoration project will be implemented in the coming year to protect the causeway and create more marsh and oyster habitat. Bayfront Park is being restored for improved access and facilities including pocket beaches. The County is exploring opportunities to improve the Cedar Point pier parking and potential boat ramp and parking on the east side of the highway to improve safety and access opportunities that are more organized than current uses. Mobile County has engaged local stakeholders to better understand safety and managed access concerns. The County is working to ensure these complementary projects and future potential projects balance habitat restoration, causeway protection, and safe managed access.