Rainwater Harvesting as an Alternative Sources of Clean Water in Semarang City –
City-dwellers in Indonesia are employing rainwater harvesting to combat the flooding and drought made worse
by climate change. “Rainwater Harvesting as an Alternative Sources of Clean Water in Semarang
City” helps urban Indonesians install rainwater catchment systems in their homes and in shared
spaces. The project improves city-dwellers access to clean water while supporting aquifer recharge.
- 60 percent of Semarang citizens not connected to water piping
- City land is subsiding at rates of up to 20 centimeters per year
- 3,000 Semarang residents benefitted from project
- City environmental agency to replicate the project
Semarang is one of Indonesia’s largest cities, with a population of more than 1.5 million. Due in part to its
topography, the public water service company is unable to serve all of Semarang’s population – so they
rely on wells, mostly shallow ones, since few people own deep wells. But drought and flooding related to climate
change are affecting these wells. During the dry season, the shallow wells run dry, and people need to buy water or
rely on government aid. During the rainy season, the shallow wells get polluted when floodwater breaches the
Overdrawing the wells during dry seasons also contributes to subsidence, a situation where ground levels sink due
to compaction of the earth as the water is removed. Subsidence represents a serious problem, particularly for
densely populated cities, as it can damage structures and create living hazards.
Semarang residents have been building rainwater harvesting systems in this partnership between the government,
local academics, non-governmental organizations (such as
ACCCRN), companies, and community members. Systems were installed in five households, as well as at an
Since the harvested rainwater is stored in closed tanks, it is kept safe from contamination during floods.
Furthermore the use of collected rainwater during the wet season allows wells to recharge, so when the dry season
comes, water is available.
Helping the planet
Harvesting rainwater puts less pressure on groundwater resources. Additionally, allowing the aquifer to recharge
helps restore ecological balance. Rainwater collection reduces runoff and thus flooding, preventing the
environmental damage such flooding may cause.
Rainwater harvesting gives city residents a clean, local, and renewable water source. Hygiene and sanitation are
improved, particularly for children and teachers at the school. City residents face fewer risks to loss of life and
property due to flooding or subsidence. They also save money from not having to purchase water, which especially
helps poorer populations.
The Semarang Environmental Agency has recognized the benefit of rainwater harvesting and replicated the project at
49 locations. These efforts can be used to inform policy-making, particularly if Semarang City incentivizes
citizens to install such systems. The project can catalyze a transformational change in behavior, as Semarang
residents change previously held views of rainwater as dirty.
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