Addressing road–river infrastructure gaps using a model-based approach

Stephanie R Januchowski-Hartley,Sayali K Pawar,Judy England,Fraser A Januchowski-Hartley,James C White

doi:10.1088/2634-4505/ac068c

Stephanie R Januchowski-Hartley, Sayali K Pawar + Show 3 more

Open Access

https://doi.org/10.1088/2634-4505/ac068c

Copy DOI

Abstract

Abstract The world’s rivers are covered over and fragmented by road infrastructure. Road–river infrastructure result in many socio-environmental questions and documenting where different types occur is challenged by their sheer numbers. Equally, the United Nations has committed the next decade to ecosystem restoration, and decision makers across government, non-government, and private sectors require information about where different types of road–river infrastructure occur to guide management decisions that promote both transport and river system resilience. Field-based efforts alone cannot address data and information needs at relevant scales, such as across river basins, nations, or regions to guide road–river infrastructure remediation. As a first step towards overcoming these data needs in Great Britain, we constructed a georeferenced database of road–river infrastructure, validated a subset of locations, and used a boosted regression tree model-based approach with environmental data to predict which infrastructure are bridges and culverts. We mapped 110 406 possible road–river infrastructure locations and were able to either validate or predict which of 110 194 locations were bridges (n = 60 385) or culverts (n = 49 809). Upstream drainage area had the greatest contribution to determining infrastructure type: when <10 km2 our model correctly predicted culverts 73% of the time but only 60% of the time for bridges. Road type and stream gradient also influenced model results. Our model-based approach is readily applied to other locations and contexts and can be used to inform decisions about management of smaller infrastructure that are frequently overlooked worldwide.

Highlights

Roads are ubiquitous (Ibisch et al 2016), and for almost every road, there is a river, stream, or creek that they cross over, run alongside, or impinge upon (Fleming and Neeson 2020)
We determined there were 60 385 bridges and 49 809 culverts (90% and 91% of which were predicted by our model, respectively with the remainder from our validated subset) where roads cross rivers in Great Britain
Upstream drainage area made the greatest contribution to the model (59.7%) and determining whether a road–river infrastructure was a bridge or culvert

Summary

Introduction

Roads are ubiquitous (Ibisch et al 2016), and for almost every road, there is a river, stream, or creek that they cross over, run alongside, or impinge upon (Fleming and Neeson 2020). With roads come makeshift crossings (Leal et al 2016) and associated infrastructure, from the obvious bridges to the more cryptic and lesser considered culverts (Januchowski-Hartley et al 2013) and fords. S R Januchowski-Hartley et al Documenting where different types of road–river infrastructure occur is a need challenged by sheer numbers along the world’s waterways. To better understand associated vulnerabilities (Pregnolato 2019) and impacts (Januchowski-Hartley et al 2013 and Fleming and Neeson 2020), road–river infrastructure are inventoried and mapped, including along some of the world’s largest freshwater ecosystems. Januchowski-Hartley et al (2013) estimated >250 000 occurrences of roads crossing over rivers in the great lakes basin in North America. To our knowledge, no study has characterized the occurrence of different road–river infrastructure types (e.g. bridges, culverts, or fords) at a national scale.

Methods

Results

Discussion

Conclusion