Mobile Bay National Estuary Program Project Implementation Committee Trade Center February 18, 2016

Transcription

1 Mobile Bay National Estuary Program Project Implementation Committee Trade Center February 18, 2016 Presented by: Elizabeth S. Godsey, P.E, United States Army Corps of Engineers, Mobile District US Army Corps of Engineers

2 Presentation Outline Project Background Study Overview Tasks & Deliverables Schedule

3 Project Background Project Background Dauphin Island is a strategically significant barrier island Over 200 acres of valuable barrier island habitat (e.g. beach, dune, overwash fans, intertidal wetlands, maritime forest, & freshwater ponds) Protects 1/3 of the Mississippi Sound and estuarine habitats in its lee (e.g. oyster reefs, mainland marshes, and seagrasses) Recently identified as globally important bird area by the Audubon Society (347 species reported) Culturally significant (Ft. Gaines) Important tourist destination Location of the State s marine education facilities Support hub for recreational/commercial fishing & the oil/gas industry

4 Events/Actions Impacting Dauphin Island Habitats Hurricanes, most recently Ivan, Katrina, & Isaac Deep Water Horizon Oil Spill Development Climate change (i.e. sea level rise & storms) Previous Efforts on Dauphin Island Rock revetment to protect Ft Gaines Project Background Groins & limited placement of material (i.e. beneficial use) on the southeastern shore Riprap protection west of fishing pier Emergency protective berms on west end Several studies & plans for restoration of Gulf beaches have been developed Comprehensive restoration plan focusing on the island s importance to natural coastal resources DOES NOT EXIST.

5 Study Description: Study Overview Collaborative effort between the USACE, USGS, and State of Alabama funded by NFWF to investigate viable, sustainable restoration options that protect and restore the resources of Dauphin Island, including habitat and living coastal and marine resources, as well as protect the coastal resources of the Mississippi Sound/Mobile Bay and the southern portion of Mobile County including the expansive Heron Bay wetlands Scope: Data collection and modeling to evaluate the most resilient and sustainable island restoration activities/configurations in support of critical habitats and resources. Budget/Schedule: $4.2M, 3.75 years - Interim report due Dec 2016 and final report by March 2019

6 Key Study Tasks Data Collection & Visualization Bathymetric & geophysical surveys USGS/USACE/ERDC: Aug Sep 2015 Tidal current measurements ERDC: Aug 2015 Wave measurements ERDC: Jun Nov 2015 Sediment characterization/distribution USGS Aug 2015 Water quality USGS Jul 2015 Jun 2016 Database & Web Visualization Tools USGS: Jun 2015 Dec 2017

7 Wave and Current Data Collection Locations

8 Water Quality Data Collection Locations Supporting Data Collection Efforts All Active Measured Observations Samples In-Situ Temperature X X Salinity X X Fixed Solids X TSS Other Phytoplankton X CHl Labile DOC X DOC Labile POC X POC=TOC-DOC Ammonium X NH4 NO2+NO3 X NO3 Labile DON X DON=DKN-NH4 Labile PON X PON=TON-DON Total Phosphate X TIP=TP-TOP, or DIP Labile DOP X DOP Labile POP X POP=TOP-DOP DO X X Dissolved Silica X

9 Data Analysis of Shorelines & Habitats Key Study Tasks (cont d) Gulf facing shoreline (USGS) Assess short and long-term shoreline change from historical beach profile surveys & aerial imagery. Estuarine shoreline & environments (USGS) Utilize changes in back-barrier estuarine shoreline trends along with cores collected at five marsh areas to evaluate feasibility of restoring/expanding marsh-wetland areas. Habitat Mapping (USGS) Develop a baseline habitat map from highresolution aerial imagery combined with field data/surveys.

10 Modeling & Additional Analyses Key Study Tasks (cont d) Sediment Budget Analysis (USACE) Develop updated topographic / bathymetric change maps (baseline is Byrnes et al., 2010 & 2012) highlighting new regions of erosion/deposition as well as volumetric change and sediment transport pathways. Hydrodynamic & Morphological Change Modeling (USGS) Evaluate restoration alternatives based on a comprehensive analysis of waves, tides, and sediment transport. Identify sediment transport drivers (e.g. storms) and pathways (i.e. alongshore vs. cross-shore)

11 Key Study Tasks (cont d) Modeling & Additional Analyses (cont d) Katrina Cut Life-Cycle Structure Response Modeling (USACE/ERDC) Evaluate the function/degradation of the structure over time & compute wave transmission over/around the structure to assess island response. Water Quality Modeling (ERDC) Understand existing WQ (i.e. ph, specific conductance, DO, turbidity, & nutrients) within MS Sound & quantify relative changes in WQ & flushing capacity resulting from proposed restoration alternatives Habitat Modeling (USGS) Utilize a predictive geospatial habitat model that s linked to the morphological change model to quantify habitat units for proposed restoration alternatives.

12 Restoration Alternatives Key Study Tasks (cont d) Alternative Formulation & Evaluation (USACE/USGS/ERDC/State) Integrate technical expertise, model results, and appropriate stakeholder objectives to identify restoration alternatives Examples could include: beneficial use options, beach/platform/dune restoration, establishment of wetlands & seagrasses, etc. Alternative Assessment Tool Development (USACE/USGS) Utilize modeling results & expert opinion to quantify the consequences of each alternative action relative to benefits, likelihood of success, and other stakeholder objectives. Cost Estimating of Alternatives (USACE) Develop Rough Order of Magnitude (ROM) cost estimates for each reasonable restoration alternative Includes costs for final engineering/design, construction, O&M, real estate, and contingency.

13 Key Study Tasks (cont d) Monitoring & Adaptive Management (USGS/USACE/ERDC) Feasibility level plan formulated around the objectives of the restoration alternatives Develop Conceptual Ecological Model (CEM) to represent understanding of the ecosystem as well as identify performance measures, monitoring parameters, & uncertainties. Will clearly identify for each objective the performance measure, monitoring purpose & design, desired outcome, and risk endpoints. Feasibility Reports Interim Report w/in 18 months (Dec 2016) including potential initial restoration projects Final report at end of project (March 2019)

14 Summary Collaborative effort between the USACE, USGS, and State of Alabama funded by NFWF to investigate viable, sustainable restoration options that protect and restore the natural resources of Dauphin Island. Extensive data collection & modeling to develop/evaluate restoration alternatives $4.2M, 3.75 years study. Started in June 2015 with an interim report due Dec 2016 and final report by March 2019.

15 QUESTIONS??

16 BUILDING STRONG