Rainwater Harvesting System to Reduce Climate Change Vulnerability - Indonesia

Rainwater Harvesting System to Reduce Climate Change Vulnerability has two goals: first, to be one of the alternatives for clean water source during a drought, and second, provide adaptation actions to reduce flooding in Semarang. This activity is currently implementing rainwater harvesting systems in public schools.

Fast facts:

This activity has the ability to cut 30% of water used during the rainy season (about six months). The benefits of rainwater utilization will be increased when a tank is used to store water;
So far, this activity has engaged a neighbourhood consisting of about 40 households next to a public school to utilize and maintain the school’s communal rainwater harvesting system;
Over 20,500 people have directly benefitted from this activity.

The problem

Semarang is one of the cities in Indonesia most impacted by the effects of climate change. Alternating floods and drought already plague the city and are expected to increase. With a population growth of 1.85% per year, this urbanization process creates much bigger runoff such that rainwater cannot be adequately absorbed into the ground.

The solution

During the rainy season, a rain harvesting system (water tank design) is used to catch
and collect rainwater. The rain harvesting system design uses gravity for water flow, reducing the electricity that would otherwise be needed for pumping. This water is then available for people to use and consume during the dry season when there is a shortage of clean water. Likewise, a rain harvesting system (absorption well design) can also capture rainwater and funnel it directly into the ground in order to conserve ground water in the future.

Helping the planet

This activity aims to be a sustainable alternative source for clean water during a drought and help implement adaptation measures to reduce flooding in Semarang.

Helping people

Poor people are the most vulnerable to climate change impacts. They have difficulties in accessing public and social facilities, including clean water. In 2009, more than a quarter of the Semarang population (26.47%) was under the poverty line. Some people use river water to meet their daily need. The water quality is very poor and users have to walk between 10-30 minutes to access the water source. Rain harvesting systems will help those people by reducing the time needed to collect water.

Scaling Up

This project has the potential to grow in size by increasing the water tank capacity, amount of tanks, or by developing a basement utilization design system.