Global environmental factors (e.g., extreme weather, climate action failure, natural disasters, human environmental damage) increasingly threaten coastal communities. Shorelines are often hardened ...(seawalls, bulkheads) to prevent flooding and erosion and protect coastal communities. However, hardened shorelines lead to environmental degradation and biodiversity loss. Developmental pressures that are growing in scale, scope, and complexity necessitate the development of sustainable solutions to work with, rather than against, nature. Such nature-based solutions (NBS) provide protection and improve environmental quality and enhance biodiversity. To further this pressing need into action, the US Army Corps of Engineers (USACE) began the Engineering With Nature (EWN) initiative to balance economic, environmental, and social benefits through collaboration with partners and stakeholders. This work shows how engineering practice can be advanced through structured decision-making and landscape architecture renderings that include ecological sciences and NBS into an integrated approach for enhancing biodiversity in coastal marine environments. This integrated approach can be applied when designing new infrastructure projects or modifying or repairing existing infrastructure. To help communicate designs incorporating NBS, drawings, and renderings showcasing EWN concepts can aid decision-making. Our experiences with implementing EWN in practice have revealed that involving landscape architects can play a crucial role in successful collaboration and lead to solutions that protect coastal communities while preserving or enhancing biodiversity.
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•Engineered coastal structures prevent flooding/erosion but can reduce biodiversity.•Nature-based Solutions (NbS) provide flood protection and improve environmental quality.•Resilient landscape architectural design can improve biodiversity with NbS.•Engineering practice can be advanced through structured decision-making.
Sea-level rise impacts on salt marsh for Guana Tolomato Matanzas National Estuarine Research Reserve are investigated using field measurements (six sites within the marsh) and a tide-marsh ...equilibrium model (Hydro-MEM). The hydrodynamic component of the model enables for prediction of spatially variable tidal data (mean low water and mean high water), which are coupled with a marsh equilibrium model (MEM) for prediction of spatially based biomass productivity of
Spartina alterniflora
. The field measurements corroborate the model results by way of prediction of relatively productive marsh at four of the six sites (percent coverage of
Spartina alterniflora
of 30–41%, canopy height of 0.27–0.67 m and simulated biomass density of greater than 750 g m
−2
over at least half of the local area within 500-m radii of the measurement sites) and relatively limited marsh at the two other sites (percent coverage of
Spartina alterniflora
of 3–5%, canopy height of 0.11–0.29 m, and simulated biomass density of greater than 750 g m
−2
over less than one-tenth of the local area within 500-m radii of the measurement sites). The model is applied in a coupled fashion for 50 years of time into the future using ten 5-year increments, where each increment of Hydro-MEM accounts for the natural accretion of the marsh, an update of the digital elevation model and bottom-friction parameterization, and the subsequent feedback to the hydroperiod and marsh productivity. Hydro-MEM is shown to exhibit rate-sensitivity with respect to sea-level rise exceeding the marsh accretion rate, whereby a sudden loss of marsh elevation occurs in such instances of marsh destabilization. Demonstrating rate-critical transition, the model proves flexible to account for the non-homogeneous and transient nature of the fast-slow variables, whereby the marsh migrates away from the tidal creeks and further into the upland zones. Practical implication of the model results is illustrated by identifying zones of lands into which marsh will be able to migrate and where existing marsh will not survive under increasing sea level. Post-analysis compares the final model output against land use/cover zonation to correct the 50-year simulation results of marsh productivity for elevation-appropriate regions but that are developed, freshwater, or otherwise inappropriate land type for salt-marsh habitat.
Reimagining infrastructure for a biodiverse future van Rees, Charles B; Hernández-Abrams, Darixa D; Shudtz, Matthew ...
Proceedings of the National Academy of Sciences - PNAS,
11/2023, Letnik:
120, Številka:
46
Journal Article
Recenzirano
Odprti dostop
Civil infrastructure will be essential to face the interlinked existential threats of climate change and rising resource demands while ensuring a livable Anthropocene for all. However, conventional ...infrastructure planning largely neglects the contributions and maintenance of Earth's ecological life support systems, which provide irreplaceable services supporting human well-being. The stability and performance of these services depend on biodiversity, but conventional infrastructure practices, narrowly focused on controlling natural capital, have inadvertently degraded biodiversity while perpetuating social inequities. Here, we envision a new infrastructure paradigm wherein biodiversity and ecosystem services are a central objective of civil engineering. In particular, we reimagine infrastructure practice such that 1) ecosystem integrity and species conservation are explicit objectives from the outset of project planning; 2) infrastructure practices integrate biodiversity into diverse project portfolios along a spectrum from conventional to nature-based solutions and natural habitats; 3) ecosystem functions reinforce and enhance the performance and lifespan of infrastructure assets; and 4) civil engineering promotes environmental justice by counteracting legacies of social inequity in infrastructure development and nature conservation. This vision calls for a fundamental rethinking of the standards, practices, and mission of infrastructure development agencies and a broadening of scope for conservation science. We critically examine the legal and professional precedents for this paradigm shift, as well as the moral and economic imperatives for manifesting equitable infrastructure planning that mainstreams biodiversity and nature's benefits to people. Finally, we set an applied research agenda for supporting this vision and highlight financial, professional, and policy pathways for achieving it.
2-Dimensional Depth-Integrated (2DDI) models are unable to represent the bottom stress in the nearshore region accurately, mainly because the bottom stress – the bottom boundary condition between the ...ocean floor and the water column – is computed with depth-averaged flow. However, the vertical current structure, which often varies significantly in direction and magnitude with respect to the mean current. This study investigates the general differences in storm surge estimation between two-dimensional (2D) and three-dimensional (3D) surge models in open-coast areas. A simplified 3D model will be implemented, which is referred to as a two-dimensional vertically resolved (2DVR) model, in which it is tacitly assumed that the momentum flux in the vertical is much larger than in the horizontal.A review of previous data and theoretical formulations (Murray, 1975; Meyers, 2008; Fewings et al., 2008; Shay, 1989) and new analyses (Burnette & Dally, 2017) of long-term observations suggest that waves and onshore winds consistently produce significant offshore directed bottom currents near coasts. An investigation of the impacts of using depth-averaged currents for open-coast surges shows that the neglect of this pervasive phenomenon results in an under-prediction of up to 25% in surge levels. A method for calculating momentum distribution through the 2DVR simulation in steady-state conditions in the nearshore region, while neglecting wave radiation stress to focus on wind-driven momentum fluxes, is developed. In this study, the nearshore region is referred to as an idealized alongshore uniform coast with constant bottom slope, from a few to tens of meters in depth. Though wind-driven currents are the focus of this work, it can be inferred that similar results would be found if waves are included as an equivalent wind stress.Variation in surge calculations between the 2DVR and 2DDI methods suggests there is a deficiency associated with depth-averaging the wind-driven currents. This deficiency must either be included as a level of uncertainty accompanying surge predictions or be identified so that a solution for overcoming it can be developed. The 2DVR simulation method presented, with further study, may offer a computationally viable solution for overcoming the deficiencies in 2DDI, 3D, and quasi 3D models.
The coastal islands and marshes of Chesapeake Bay USA, are disappearing along with the ecosystem services and infrastructure/shoreline protection they provide. To counter such losses, the USACE ...Baltimore District is restoring historic island footprints using dredged sediments. Islands constitute an important natural and nature-based feature (NNBF) that meet the 'triple win outcomes' of USACE's Engineering With Nature (EWN) initiative, by providing economic, social and environmental benefits. Here we highlight the restoration and monitoring of Swan Island using 61,000 cubic yards of dredged sediment. The creation/expansion of Swan Island, is expected to produce significant benefits in terms of ecosystem services, increased resilience to future sea level rise, and abatement of erosive losses to an adjacent coastal community. The pre- and post-restoration monitoring and model development by project partners will serve to quantify the benefits and efficacy of the island restoration thereby facilitating island restoration as a viable NNBF option in the future.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/2kvSVcH2KuE
Long term sustainability in salt marsh and mangroves is dependent on dominant species, such as Spartina alterniflora, to capture organic and inorganic sediment. The research analyzes that ...sustainability. This work demonstrates the prediction of hydrodynamics and biomass density of salt marsh to provide useful information for the planning and mitigation of sea-level rise impacts on marsh sustainability in the Guana Tolomato Matanzas National Estuarine Research Reserve (GTMNERR), Florida. An advanced circulation code was applied to simulate hydrodynamics (i.e., shallow water equations) in the GTMNERR. The model used a set of parameters and conditions based on the GTMNERR domain to predict tides for present-day conditions, which was validated using tidal data from eight monitoring stations within the GTMNERR. The hydrodynamic model results (i.e., MLW and MHW) were then coupled with a marsh equilibrium model to assess year-to-year biomass density for saltmarsh cordgrass (Spartina alterniflora). Vegetative data were obtained from the staff of the GTMNERR and organized for future work towards validation of biomass density predictions.
Simulations were then performed with sea-level rise scenarios of 0.13 m, 0.22 m and 0.51 m, which are standardized cases of mild, moderate, and extreme rise for the northeast coast of Florida. The simulation results show nonlinear increase of tidal datums for given sea-level rise, thus leading to nonlinear change in biomass productivity. The modeling tool has engineering implications in the way of assisting the planning of dredging spoils to be laid over the marsh to sustain existing marsh against rising sea levels. The modeling tool further provides information about marsh migration due to sea-level rise, whereby coastal planners can use this information to designate and preserve existing uplands/wetlands that will house salt marsh in the future, as the marshes will migrate into such upland/wetlands areas.
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