The government says extreme weather events are a serious threat to water security. During the wet season floods large swaths of the country, including Jakarta, are inundated by floods. At other times droughts cause drinking water shortages for millions. Below is the final article in a series of six on climate change mitigation and adaptation.
Adianto P. Simamora, The Jakarta Post, Jakarta
The government said demand for clean water, particularly in Java, Bali and East Nusa Tenggara far exceeds supply, forcing people to `over-exploit' groundwater.
Demand will continue to increase in line with population growth, at a time when potable water supplies are drying up due to unpredictable changes in the weather.
Further along in the worrisome cycle, the government said, seater will further intrude into coastal areas where millions reside, severely impacting water security.
Data from the state ministry of environment said the country's annual demand for clean water would reach 8.9 billion cubic meters in 2015, almost a three-fold increase since 1990 when demand was only 3.1 billion cubic meters.
According to a written action plan, the government will build water catchment facilities such as lakes and percolation pits to harvest water during the rainy season and store it as a source of clean water during dry months.
These facilities are to be concentrated in Java, Sumatra, Sulawesi, Bali, West Nusa Tenggara and East Nusa Tenggara.
The government also plans to rehabilitate natural river drainages in an as effort to improve quality and supply of raw water.
According to the environment ministry, 62 river basins are in critical condition as of 2007, significantly more than the 22 in poor shape in 1984.
The ministry said highland deforestation in upstream areas and sweeping changes in land use have damaged natural drainage systems.
A joint study in April by World Wildlife Federation Indonesia and Bandung Institute of Technology's meteorology lab predicted less rainwater would flow through the Citarum river basin in West Java as a result of warmer temperatures and land use changes.
The Citarum River basin, Java's largest drainage, comprises 6,080 squares kilometers of land, through which the 269-kilometer river flows.
The study predicted dry and wet season temperatures in the basin would be significantly higher by 2020.
Citarum basin is the primary source of water for Jakarta and West Java.
The Jakarta administration said the capital city needed around 547 million cubic meter of water per year.
However, the two domestic use water operators -- Thames PAM Jaya and Palyja -- are able to pump no more than 295 million cubic meters of water per year.
Some of the capital's residents privately exploit groundwater which, the administration said, was speeding up land subsidence in the city.
The action plan says new technology is needed to utilize seawater as source for drinking water and for improving the function of rivers in recharging groundwater supplies.
It will also conduct campaigns aimed at increasing water conservation, including in agriculture, industry and power generation.
Data from the ministry indicated there were no rivers up to standard required to become a source of drinking water due high levels of pollution.
The World Bank has blamed unsafe drinking water and inadequate sanitation for 88 percent of total disease rates, including diarrhea and malaria.
It said that about 1.1 billion humans lack access to potable fresh water and some 2.6 billion are without adequate sanitation.