“There is no existing infrastructure to utilize a large number of rivers flowing into the ocean south of Bali. The water in these rivers is practically discarded and flows into the sea, instead of being tapped, processed and piped as a clean water source for the public,” researcher Ketut Gde Dharma Putra said.

Darma Putra heads Udayana University’s center for sustainable development study and was a member of the team that carried out the JICA (Japan International Cooperation Agency)-funded 2006 study on the island’s water resource. The study concluded that by 2015 the southern Bali region (Denpasar, Badung, Gianyar and Tabanan) would face a severe water crisis with a deficit in water supply of 1,500 liters per second.

“The study took into consideration several main indicators, including the increasing number of housing and hotel constructions, and the region’s existing water resources,” he said.

Southern Bali is the island’s most populated area and the host of its most popular tourist destinations, from Ubud in Gianyar, Sanur in Denpasar, Kuta and Nusa Dua in Badung and Tanah Lot in Tabanan.

“The study has actually recommended the construction of water management infrastructure, particularly for storing and processing the water, at several rivers in the island,” he said.

The study identified that such facilities should be constructed at Unda River in Klungkung, Petanu River in Gianyar and Penet River in Tabanan. Unda’s estimated capacity is 1,800 liters per second while Penet is 300 liters per second. The combined capacity of the three rivers could reach 2,500 liters per second, more than sufficient to offset the predicted water deficit. “If the government does nothing to utilize those rivers, then naturally we will face a water shortage,” he added.

So far, the local administration has utilized Badung River, establishing an estuary dam at its mouth.

“The estuary dam actually could generate a large amount of water supply for the Nusa Dua area,” he said. 

“It could produce water up to 900 liters per second. The dam’s existing infrastructure is limited and can only produce up to 300 liters per second of water.” 

Utilizing the rivers’ water resources, he argued, would of course decrease the utilization of underground water resources.

“The cost of acquiring and maintaining underground water wells is much higher than the cost of utilizing surface water. However, a large number of hotels use underground water wells because they do not have alternatives,” he said.

Mass utilization and consumption of underground water resources would also have a negative environmental impact, including the intrusion of sea water. 

The JICA study shows that nearly every coastal town and village in South Bali has encountered a sea water intrusion. 

The worst type of intrusion affects Kuta and Tanjung Benoa. 

In Kuta, sea water has intruded up to 25 meters from the shoreline.