Why does Rain Paralyze Tbilisi?

In recent years, spring rain has become an urban disaster for Tbilisi. It causes floods in Tbilisi streets and paralyzes the city. Heavy rain also affects other big cities since the absence of green spaces hinders water absorption. Instead of draining in the ground, water runs on surfaces and carries garbage, bacteria, and chemicals gathered from the landscape. Stormwater runoff leads to floods and an erosion of urban waterways damages infrastructure.

An early system of rainwater management was similar to modern infrastructure: the system of sewers and pipes that deliver stormwater runoff to the nearest river or a lake. This infrastructure is commonly referred to as “gray stormwater infrastructure”. They aim at one purpose: to divert water away from the urban environment. However, as scientists claim, using only this method, to avoid flooding, is no longer effective due to the climatic changes, which has changed the nature of floods itself.

Most of the infrastructure was built at for the time when climate conditions were different. Today’s storms are often more intense and localized. To cope with these new challenges, cities started to invent new methods like green infrastructure, which uses nature to help managing stormwater. Examples of green infrastructure which help to reduce grey infrastructure’s load are permeable-paved roads, which are built with water-pervious materials. Green roofs and rain gardens naturally absorb rainwater.

One of the functions of green infrastructure is to reduce damage from heavy rain with bioswales, which consist of curved landscape masses with sloped sides that are often placed near parking lots to remove pollution from automobiles.

To improve the system against flooding and stormwater, together with the green infrastructure, cities are introducing sensors that measure various factors such as air quality, weather conditions, noise, and traffic.

By combining sensors and green infrastructure together with grey infrastructure, Chicago provided an innovative solution for an everyday urban problem: rainwater. The main aim of the project was to create a tool to reduce urban flooding and prevent millions of dollars loss, caused by property damage.

This innovative approach to with a level of strategy, efficiency, and effectiveness previously unavailable in stormwater management.

Tbilisi is a growing city with major ongoing constructions. For this stage of the city development, it is important to take into consideration the issues, that may cause huge problems after several years.

Three years ago on June 13, 2015, a significant flood occurred in the Vere River valley which resulted into at least 20 deaths.