Erosion Risk Modelling: An Improved Screening Tool for Urban Watershed Management
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Date
2025-01-02
Advisor
MacVicar, Bruce
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Publisher
University of Waterloo
Abstract
Urbanization alters hydrological responses by increasing impervious surfaces, leading to elevated runoff, altered streamflow regimes, and heightened flood risks (Paul & Meyer, 2001; Walsh et al., 2012). The impact of land-use changes is a crucial consideration for urban watershed management (Bochis-Micu & Pitt, 2005; Walsh et al., 2012). SPINpy 2 is a screening tool that utilizes digital elevation model (DEM)-based methods of stream power mapping from Vocal Ferencevic and Ashmore (2012) to integrate land-use data into its modelling framework.
This study presents the development of two of SPINpy 2's Land Use (LU) based analyses: i) the No Stormwater Management (NSM) Scenario and ii) the Engineered Stormwater Management Pond (ESM) Scenario. Incorporating Nature-based Solutions (NbS), such as stormwater management ponds, into SPINpy 2 can model methods to alleviate the adverse effects of urbanization by promoting infiltration and stabilizing stream banks. This feature is particularly valuable for urban watersheds at high erosion risk, where NbS can help reduce the effects of impervious surfaces, lower flood risks, and stabilize channels. SPINpy 2 facilitates the modelling of NbS, assessing their effects on stream power, discharge, and erosion sensitivity and providing a decision-support tool for urban watershed managers. It helps evaluate the long-term benefits of NbS in reducing runoff and enhancing ecosystem resilience. By modelling the effects of reducing peak flows on erosion risk, SPINpy 2 simulates how stormwater management measures can mitigate erosion and offers insights into effective strategies for enhancing channel stability.
The model was applied to urbanized watersheds such as Cooksville Creek to assess its utility in high-risk environments. The simulation results provide insights into the potential of NbS to reduce flood risks and improve channel stability. The application of SPINpy 2 demonstrated that incorporating NbS significantly mitigates the impacts of urbanization. Comparisons between scenarios with and without NbS interventions highlighted the importance of infiltration-based solutions in stabilizing stream channels and reducing sediment transport. SPINpy 2 also provided spatially explicit maps showing locations of high erosion risk and areas where NbS would be most effective.
The findings underscore the potential of SPINpy 2 as a decision-support tool for urban watershed managers. By simulating the impacts of land-use changes and NbS interventions, SPINpy 2 offers a proactive approach to addressing hydrological and geomorphological challenges posed by urbanization. The ability to model diverse NbS scenarios enhances the tool's applicability in high-risk watersheds, such as Cooksville Creek, where impervious surfaces dominate and flood risks are heightened. The results demonstrate that NbS can substantially reduce runoff and stabilize channels, promoting ecosystem resilience and sustainable development.
Overall, SPINpy 2 serves as a screening tool for decision-makers, enabling them to simulate and evaluate the impacts of land-use changes and NbS interventions, promoting sustainable development and environmental stewardship in urban environments. Its comprehensive approach allows watershed managers to tackle the unique challenges posed by urbanization and supports the development of cost-effective and environmentally sound infrastructure and policies. This proactive, integrative approach positions SPINpy 2 as a key resource for managing urban watersheds.
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Keywords
NATURAL SCIENCES::Earth sciences::Atmosphere and hydrosphere sciences::Hydrology, Erosion, Watershed, Stream Power, Screening Tool, Watershed Management