“Garbage in, Garbage Out” Does Not Hold True for Indigenous Community Flood Extent Modeling in the Prairie Pothole Region

Anuja Thapa,Anthony Johnston,Graham Strickert,Lori Bradford,Xiaolei Yu,Kelsey Watson-Daniels

doi:10.3390/w11122486

Abstract

Extensive land use changes and uncertainties arising from climate change in recent years have contributed to increased flood magnitudes in the Canadian Prairies and threatened the vulnerabilities of many small and indigenous communities. There is, thus, a need to create modernized flood risk management tools to support small and rural communities’ preparations for future extreme events. In this study, we developed spatial flood information for an indigenous community in Central Saskatchewan using LiDAR based DEM and a spatial modeling tool, the wetland DEM ponding model (WDPM). A crucial element of flood mapping in this study was community engagement in data collection, scenario description for WDPM, and flood map validation. Community feedback was also used to evaluate the utility of the modelled flood outputs. The results showed the accuracy of WDPM outputs could be improved not only with the quality of DEM but also with additional community-held information on contributing areas (watershed information). Based on community feedback, this accessible, spatially-focused modeling approach can provide relevant information for community spatial planning and developing risk management strategies. Our study found community engagement to be valuable in flood modeling and mapping by: providing necessary data, validating input data through lived experiences, and providing alternate scenarios to be used in future work. This research demonstrates the suitability and utility of LiDAR and WDPM complemented by community participation for improving flood mapping in the Prairie Pothole Region (PPR). The approach used in the study also serves as an important guide for applying transdisciplinary tools and methods for establishing good practice in research and helping build resilient communities in the Prairies.

Highlights

Floods are considered to be natural processes [1]; in recent years, the global increase in flooding incidents has been associated with climate change [2,3]
The final spatial distributions of simulated runoff for Mistawasis Nêhiyawak light detection and ranging (LiDAR) digital elevation models (DEM) are shown in Figure 5 for the four scenarios
Findings from earlier work and this study indicate that without the information of the surrounding contributing areas extending to the hydrosheds, and in the best case, watershed boundaries, the use of LIDAR DEM with wetland DEM ponding model (WDPM) leads to an exaggerated inundation area

Summary

Introduction

Floods are considered to be natural processes [1]; in recent years, the global increase in flooding incidents has been associated with climate change [2,3]. Pothole Region (PPR), is characterized by millions of wetland depressions, known as potholes [5,6] While many of these depressions are isolated, they can occasionally connect at times of high overland water flow through a mechanism known as ‘fill and spill’ [5,7]. The extensive land use change in the PPR and uncertainties arising from changing climate change, have increased flood magnitudes in the Prairies [6,8]. These increases intensify vulnerabilities in rural communities. There is, a need to create modernized flood risk management tools to support community preparation for future events brought on by the climate emergency

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Results

Discussion

Conclusion