# Part 1: Environmental Risks from BRI Investments in Transport

Transportation infrastructure can pose many risks to the environment. In this section we distinguish direct effects – abiotic, ecosystems, wildlife – from the indirect effects induced by changes in transport costs and land use. While the former tend to be localized and unambiguously linked to a road or rail project, the latter often have more complex connections but potentially more pervasive impacts. The magnitudes of various effects differ by context. As illustrated in Appendix 1 ( _Forest Cover Change Across the Entire Belt and Road_ ), deforestation – a relatively straightforward proxy for environmental risks – has shown heterogenous responses to transportation investments, depending upon both the ecological and development settings in which investments occur. Cumulative risks of multiple factors are even more challenging to assess and predict, as these factors may evolve and also may interact.

Environmental risks are typically divided between those incurred in the design and construction phases of any infrastructure project and those experienced during the operations. This working paper will only review the latter because the former tend to be extremely site specific and can be confidently identified during a project feasibility study or environmental impact assessment process (World Bank 2012).

## I. DIRECT EFFECTS

A. Abiotic Effects i. Edaphic, Topographic, and Hydrologic Impacts Once operational, roads modify their physical environment by alterations of hydrologic systems, sediment erosion dynamics, and debris deposition dynamics. The extent and intensity of these abiotic effects can vary as a result of the position of the road relative to slope, nearby waterways and drainage, surrounding land cover, and prevailing winds (Coffin 2007; Forman 1998; Sidle, Ghestem, and Stokes 2014). Most abiotic factors have localized effects immediately around the road and roadside. These impacts can be severe, as in the case of destructive landslides that damage nearby communities and ecosystems. Some abiotic effects, however, permeate across a wider landscape. For example, poorly constructed roads on mountainous terrain can generate increased sedimentation in rivers and streams, creating long‐term effects on downstream aquatic communities and producing widespread flooding risks (Forman 1998; Renaud, Sudmeier‐Rieux, and Estrella 2013; Sidle, Ghestem, and Stokes 2014). Because so many of the BRI Economic Corridors pass through steep terrain, BRI transportation projects are especially vulnerable to such risks. The consequences can be severe: Twenty‐five million inhabitants living downslope from two proposed BRI road projects in Myanmar, for example, are potentially at risk due to vulnerability to increased sedimentation and flooding (Helsingen et al. 2018).

There is little environmental research (beyond engineering feasibility plans) on the effects of railways on hydrologic systems, sediment erosion, and debris deposition. However, it is expected that they will be similar to roads, with impacts depending on topography, hydrology, and climate. It is possible that risks related to uneven topography and steep slopes may be more severe for rail projects (especially HSRs), which for engineering purposes are constrained to relatively straight trajectories. Less able to adjust to the terrain, HSR may face greater complications than roads, and may require more tunnels and bridges.

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