The government of Georgia has requested the assistance of the Asian Development Bank (ADB) to improve the Shorapani–Argveta Road Section F4 of the E60 East-West Highway. The proposed section improvement requires the construction of 12 tunnels (6 double tubes), 14 bridges, 4 interchanges and several deep cuttings and high embankments with a total length of 14.7 km. FutureWater has undertaken a Climate Risk and Vulnerability Assessment (CRVA) in which (i) the sensitivity of the project components to climate and/or weather conditions has been assessed, and (ii) climate risks and adequacy of proposed technical solutions have been assessed.
Due to its geographic location, Georgia’s role as a major transit country is significant. Transport of goods into and through Georgia has increased over the past 10-15 years. Almost two-thirds of goods in Georgia are transported by road but the roads are poorly equipped to cope with the volume of traffic and the proportion of heavy vehicles, and factors such as insufficient dual carriageways, routing through inhabited areas and inadequate maintenance and repair, hinder throughputs and increase transit times. The government of Georgia has therefore launched a program to upgrade the major roads of the country, including part of the East-West (E60) Highway. This climate risk and vulnerability assessment (CRVA) has examined the proposed components for section Shorapani-Argveta (F4) of the East-West Highway Road Project. The climate model analysis yields following conclusions:
- Temperature increases by about 2.1 °C (RCP4.5) to 2.9 °C (RCP8.5) are to be expected
- Minimum and maximum temperature are likely to change inconsistently, with maximum air temperatures increasing more than minimum air temperatures. This implies a larger diurnal temperature range for the future
- Extremes related to temperatures (e.g. warm spells, extremely warm days) are likely to increase in frequency and intensity
- Precipitation totals are likely to stay reasonable constant
- Precipitation extremes are likely to increase in frequency and intensity. Maximum 1-day precipitation volumes with return periods of 25, 50 and 100 years are expected to increase by about 10% to 20%.
The increase in extreme precipitation events is considered as the most important climate risk for the project road. This may lead to higher extreme discharges that exceed the systems’ design capacity and cause flooding or inundation of road infrastructure. More extreme precipitation events can also lead to increased slope instability alongside the project road, causing more frequent and more powerful landslides, rockfalls and/or avalanches. In addition, the projected increase in diurnal temperature variability may lead to an increase in freeze–thaw conditions. This may result in deterioration of road pavement integrity, resulting in more frequent maintenance requirements. It can also further increase the risk of slope instability, making any stretch of road close to steep terrain more vulnerable to such mass movement phenomena.
According to the design team, the structures at risk of flooding (e.g. bridges, road sections) are sufficiently dimensioned to cope with return levels 10-20% higher than used in the original design calculations, which can be reasonably assumed. Retaining walls and mass movement protection structures are in place. The performance and sustainability of the pavement structure and structural joints may be adversely affected by the increase in the diurnal temperature range. To mitigate this risk, it advised to use road pavement with highest capability.
2019 - FutureWater Report 189
TA-9755 GEO: East-West Highway (Shorapani- Argveta Section) Project, Georgia. Climate Risk and Vulnerability Assessment.
Nolet, C., A.F. Lutz