3D model development of riparian tree root systems using photogrammetry (Collaborator: Thibaut Houette - University of Akron)
October 2018 - Current
Manual measurement of tree root traits (i.e. diameter, surface area, branching angle) is tedious and time-consuming. Currently available scanning technologies to both generate coarse root architecture models and automate analysis of tree root traits are often not precise, expensive, necessitate a lot of equipment, or require transporting the root structure off site. Both 3D models and quantitative root traits across species and site locations, including difficult-to-access sites, would be useful to urban foresters, arboriculturists, engineers, landscape architects and ecologists alike. Access to this 3D information (in addition to biomass) would allow for the opportunity to gain a better understanding of root-soil interactions, root stability and development of predictive models, the effects of soil compaction and impermeable layers on root growth and structure, impact of root structure on water permeability, and quantification of ecosystem services that trees provide in urban communities, from stormwater management to erosion prevention. The goals of the proposed research project are to: (1) develop an in-situ field application of a new digital technology, structure from motion (SfM) photogrammetry, to generate 3D models of coarse root architecture of a minimum of five different (riparian) species in Northeast Ohio, (2) generate computer and physical 3D printed models (1:1 to 1:30 scale) as research, teaching, training and outreach tools, (3) extract quantitative root traits to compare across species, age and/or site conditions and (4) use both models and root trait analysis to develop design proposals for the areas of coastal infrastructure and adaptive building foundations.
Near-wake turbulent flow structure downstream of a modeled rootwad (Collaborator: Dr. Wei Zhang - Cleveland State University)
August 2019 - Current
Rootwads, defined as the full trunk of a tree with root base, are often locally acquired on site and used in river and stream restoration projects for bank stabilization, hydrodynamic reduction and habitat reduction. Increasingly, rootwads are also used in coastal restoration projects to attenuate waves, stabilize shorelines, promote sediment deposition and provide habitat when applicable and available. In urban environments, local access to large trees is unlikely and urban shorelines do not easily facilitate the use of large wood structures. Developed from real root systems using SfM photogrammetry, this experimental study describes the mean and turbulent flow structure in the wake behind several distinct 3D models of a single rootwad with root fan facing in the direction of the incoming uni-directional flow in a laboratory water channel. Real root structures present significant variation in diameter and curvature, in which this variation is typically not considered in circular patches of rigid or flexible cylinders modeling mangrove roots nor in multiscale fractal branched structures modeling tree canopies. The patch diameter (i.e. macro diameter), D, and patch density (i.e. root density - frontal area per volume), a, will be varied for several distinct 3D rootwad models with varying distributions in diameter and curvature to examine the effects of key tree root traits (i.e. root morphology parameters) on the induced downstream wake structure using particle image velocimetry (PIV). We plan to determine if and where via determination of distance L1 and L2 behind the rootwad where fine and coarse-particle distribution can occur, respectively, and where via determination of distance L3, turbulence associated with wake-scale vortices inhibits deposition. Characterization and quantification of downstream reduced flow regions will enable habitat prediction of keystone freshwater fish and aquatic plant species that only thrive in specific flow ranges. This study will suggest several geometrical parameters to consider in the design of bio-inspired coastal infrastructure prototypes modeled after rootwads, to be used in urban environments where there is a lack and difficulty in using real trees, in which flow attenuation, sediment deposition and habitat creation are optimized for maximum benefit of people and planet.
Experimental study on shoreline erosion following placement of modeled rootwads using the EM2 Geomodel (Collaborator: Dr. Anne Jefferson - Kent State University)
April 2020 - Current
Using a wave maker accessory for the EM2 Geomodel by Little River Research & Design, this study will investigate the effect of the number and configuration of 3D model rootwads on cross-section and long-profile shoreline morphology via longshore drift. A high and low water level, as well as a high and low wave condition will be tested.
Freshwater submersion study of alternative materials for temporary coastal construction
January 2020 - Current
The majority of coastal infrastructure is manufactured with concrete, rock and steel. While cheap and relatively available with established manufacturing processes, these materials have several limitations. First, the materials do not offer the flexibility to respond to changing coastal dynamics and forces as the structures are often permanent upon installation due to their weight, bulkiness and insolubility in water. These materials are also limited in their capability to incorporate complex design features due to the necessity of high heat, pressure and force to shape these materials. What additional ecological restoration opportunities may become possible with the use of biologically based, temporary and fully dissolvable synthetic structures that allow for complex design features under relatively low heat, pressure and force? With the advent of additive manufacturing combined with the growing trend of disposable (or multi-use) compostable items replacing single-use plastics, the family of biodegradable aliphatic polyesters fit the criteria noted in the exploration above. The best known of the currently available types of this family of materials are poly(3-caprolactone) (PCL), polymers of lactic and glycolic acids (polylactides and polyglycols (PLA and PGA), respectively), and polyesters of microbiological origin (polyhydroxyalkanoates, PHAs). PLA is the simplest in its degradation process, degrading first through an abiotic hydrolysis reaction into carboxylic acids, carbon dioxide and water, then these degradation by-products are consumed by microorganisms. It is common to add natural fibers to biodegradable polymers to modify the mechanical, thermal and processing properties of the composite for use as a product, while still retaining a completely biodegradable material, but fiber additions can affect the degradation rate of the composite in water. Some bio-composites are being considered as material components of boats as they offer high specific stiffness and low environmental footprint compared to petroleum-based polymer composites. In this experiment, natural biological and mineral powders and fillers that inhibit water intrusion will be added to PLA to make several bio-composites. Material samples will be submerged in a freshwater environment, monitoring degradation via mass loss, biological colonization by type and genus via visual and microscopic identification, and morphological and surface changes by SEM through periodic removal of the samples.
Development of biomimetic coastal infrastructure concepts modeled after rootwads and identification of pilot test locations along the Ohio Lake Erie shoreline using landscape design principles (Collaborator: Dr. Reid Coffman - Kent State University)
January 2021 - Current
Informed by the outcomes of the first three projects, several shore structure templates modeled after rootwads will be developed. These templates and relevant design principles will be designed and written for inclusion into an updated version of the Ohio Coastal Design Manual. Identification of applicable shoreline types or reaches for testing feasibility and effectiveness on Lake Erie will contextualize and situate the final design proposals. Identification of these shoreline reaches will be informed by interpretation of available coastline structure, land use types, vegetation and forest cover data and historical maps of the Ohio Lake Erie shoreline. Due to a unique partnership with Additive Engineering Solutions (AES) in Akron, Ohio, it is possible a 1:1 or 1:2 scale prototype can be 3D printed for display as a proof-of-concept, serving as both a scientific and artistic endeavor. This prototype could be displayed at Ingenuity Cleveland (an annual arts, science and technology festival in the region) and/or Myers School of Art as an environmental education - art exhibition, to be deployed as a pilot test at the appropriate site upon conclusion of the exhibition.