1.2 Three levels of road resilience for different road elements

TABLE 1.2 Three levels of road resilience for different road elements

BASIC RESILIENCE: PROTECTIVE

KEY OBJECTIVE: PROTECTING ROAD INFRASTRUCTURE RESILIENCE PLUS 1: ADAPTIVE

KEY OBJECTIVE: MAKING THE BEST USE OF, AND ADAPTING TO, HYDROLOGICAL CHANGES INTRODUCED BY THE ROAD RESILIENCE PLUS 2: PROACTIVE

KEY OBJECTIVE: REDESIGNING ROAD INFRASTRUCTURE TO OPTIMIZE THE AREA’S WATER MANAGEMENT AND CLIMATE RESILIENCE, OFTEN TO BENEFIT LIVELIHOODS

Bridges

Drifts

Paved roads Increase dimensions to accommodate flood peaks and prevent flood congestion; deepen abutments

Use higher spillways and larger aprons to accommodate peak floods

Increase capacity of road drainage; reinforce drainage infrastructure; build more weatherproof road surfaces, impermeable pavements, and embankments

Unpaved roads Increase cross drainage and protect road surface with additional layers of aggregate

Roadside slopes Adjust critical slopes

Drainage structures Increase dimensions to accommodate larger flood peaks

Borrow pits Not applicable

Roadside vegetation Not applicable

Source: MetaMeta, (www.roadsforwater.org). Integrate bridge crossing into catchment management to reduce riverbed siltation and mitigate flood peaks Use drifts and small fords to stabilize erosive streams

Manage catchments to retain water and control erosive runoff to reduce risk to infrastructure

Manage catchments to retain water and control erosive runoff to reduce risk to infrastructure; protect road surface with water bars, dips, and infiltration bunds

Implement bioengineering and vetiver planting for productive use Implement gated control and water spreading from culverts and drains

Systematically convert borrow pits for storage, seepage, or recharge Systematically promote roadside planting for sequestration and better dust control and microclimate Use bridge sills for controlled drainage and wetland management; consider drifts instead of bridges to stabilize riverbeds Use nonculvert drifts for water retention, river stabilization, and floodwater spreading Consider changed alignment and cross drainage for water storage and recharge

Include basic drainage for water harvesting as part of road development; take measures to manage subsurface flows; protect catchments

Implement bioengineering and vetiver planting for productive use Place culverts to optimize drainage pattern for water harvesting Plan new borrow pits to optimize storage functions after conversion Systematically promote roadside planting for sequestration and better dust control and microclimate

critical resources but can also directly improve agricultural productivity and employ local people in road works that might otherwise rely on heavy equipment and skilled workers from distant communities. • The additional cost of integrated road-water management is a small fraction of the overall outlays for road investment or road repair and maintenance, typically adding less than 5 percent to the cost of road investments. This cost may be financed from climate funding top-ups for road infrastructure programs. • The cost of roads for water for building climate-resilient roads that work with the landscape to harvest water and manage floods is generally lower than the cost of adopting new design specifications called for by the basic resilience approach to climate resilience.

Green Roads can better manage climate risks to road infrastructure and simultaneously enable sustainable management of water and more productive use