Knowledge-Based Predictive Tools to Assess Effectiveness of Natural and Nature-Based Solutions for Coastal Restoration and Protection Planning

Abstract

Predictive tools are widely used to study coastal and deltaic systems in support of basic research, planning efforts, engineering design, and the implementation of restoration or protection strategies. They have been extensively used to evaluate the effectiveness of natural and nature-based solutions (NNBS) to support ecosystem functions and services of coastal ecosystems and human communities experiencing increased risk from sea-level rise and severe storms. The potential benefits of NNBS are being increasingly recognized, particularly in remote areas or areas that are either technically or financially infeasible to be protected with levees or other difficult engineering alternatives. Local communities, however, are often excluded from proposing, screening, or evaluating NNBS as restoration and protection strategies. Communities are also not sufficiently involved in the development or application of the predictive tools. This research effort outlines an approach to developing knowledge-based predictive tools and a community engagement process to evaluate NNBS strategies proposed predominantly by local communities. Incorporating knowledge from local communities benefits and potentially improves the performance of predictive tools and their ability to capture visible trends and observations. To illustrate this concept, the authors present landscape models for coastal Louisiana that successfully reproduced the frequency of flooding of local roads, rate of shoreline erosion, salinity pattern changes, and presence/absence of key species (e.g., brown shrimp, oysters, and so forth). While these qualitative measures are not a substitute for well-established rigorous and quantitative model performance assessment approaches, they offer an effective approach to engage local communities and incorporate their knowledge in the development of the predictive models and the proposed protection and restoration strategies to be examined.

Getting the message right on nature‐based solutions to climate change

“…First, as discussed in Sections 3.2 and 6.2, NbS should be co‐designed and co‐implemented through an equitable participatory process involving IPLCs, other stakeholders and researchers. This should bring together different forms of knowledge in a transdisciplinary and cross‐sectoral approach, giving indigenous and local knowledge due representation (Chazdon, 2020; Lavorel et al, 2019; Meselhe et al, 2020). Researchers and research‐users should agree on research aims and co‐produce the evidence base needed to support well‐designed NbS (Hoffmann et al, 2019; Knapp et al, 2019), and researchers must communicate their findings in clear, policy‐relevant ways (Neßhöver et al, 2013).…”

Ecohydraulics of Surrogate Salt Marshes for Coastal Protection: Wave–Vegetation Interaction and Related Hydrodynamics on Vegetated Foreshores at Sea Dikes

“…Dunes, coastal forests, and salt marshes are examples for ecosystems that provide ecosystem services (ESS) relevant in conjunction with coastal defense and flood protection (Hanley et al 2014;Kathiresan and Rajendran 2005;Silva et al 2016). These have been classified as "natural" or "nature-based solutions" (Meselhe et al 2020). In that context, the values and services provided by salt marshes are, e.g., blue carbon storage, habitat provision, ecosystem functioning, and the reduction of construction and maintenance cost, compared with dikes and sea walls without vegetated foreshores (King and Lester 1995;Barbier et al 2011;Purcell et al 2020).…”

Coastal flooding will disproportionately impact people on river deltas

“…But, these engineering solutions are expensive and can fail when floods exceed the design limitations. A nature-based solution to limit coastal flooding is to allow deltaic growth to fill in these flood zones with sediment 33 – 35 . Indeed, this is what a delta does as it grows; areas that are dissected by channels repeatedly flood and receive more sediment 36 , 37 .…”