Proposed Dams in the Kaliwa River watershed
Several bulk water supply projects on the upper portion of the Kaliwa River Watershed have been proposed by the Philippine Government since the 1970s, with the intent of relieving Metro Manila of its overdependence on the water supplied by Angat Dam. Most of these have focused on a particular site in Barangay Laiban in Tanay, Rizal, on the upper portion of the Kaliwa River Watershed, and the projects have thus often been referred to as Laiban dam or Kaliwa dam, although multiple projects have been referred to using either name.
Due to controversies regarding the project's environmental impact and its potential effect on local communities, notably including a community of Remontado Dumagat people who consider the area part of their ancestral lands, these projects have been controversial and have thus been alternatingly approved, deferred, cancelled, and reapproved by the Philippine Government at different times since the late 1970s.
The Laiban sub-watershed site
The Laiban site where the project is supposed to be built is a Barangay of municipality of Tanay in the province of Rizal, east of Metro Manila. It contains he 180 ha Laiban sub-watershed, a microbasin of the bigger Kaliwa Watershed, nestled in the southeastern portion of the Sierra Madre Mountain Range.The Kaliwa Watershed forms part of the Sierra Madre Biodiversity Corridor, and has been identified by the Southern Sierra Madre Wildlife Center of the Environmental Studies Institute of Miriam College as one of the SMBC's 14 priority biodiversity conservation sites. It is described as "an important wildlife habitat that contains dipterocarp trees, a wide array of birds, mammals, amphibians and reptiles, some of which are threatened and endemic species."
In 1999 the Kaliwa Watershed, evaluated at the time as "degraded due to anthropogenic pressures", was classified as a protected area under the National Integrated Protected Areas System.
The terrain is generally mountainous, surrounded by slopes > 50%, consisting partly of forested hills and partly of cultivated land, with some slash and burn cultivation areas present. Its elevation is from 220 masl to 1,530 masl. A number of small creeks run through the lower slopes, all eventually connecting to the main river.
The village also serves as home to the indigenous Remontado Dumagats.
Historical projects
The Manila Water Supply III project under the Marcos administration
The history of projects on the Kaliwa River watershed began with the conception of the Manila Water Supply III project in November 1979 during Martial Law under Ferdinand Marcos when then-President Marcos deferred a project which would have placed a dam in the Markina River, and instructed the MWSS to look for alternative sites. The MWSS identified the Kaliwa River basin to be the most viable alternative, and began the first World Bank feasibility study on the damming of the Kaliwa river in 1979.During that time, however, the Philippine economy had gone into rapid decline because Marcos' debt driven deficit spending made the Philippines vulnerable when the United States increased its interest rates in the third quarter of 1981. The ensuing collapse of the Philippine Economy, worsened by the political pressure after the assassination of Benigno Aquino, led to slow development of the Laiban dam project until Marcos was forced out of office and into exile by the 1986 People Power Revolution.
By 1989, the succeeding administration of Corazon Aquino reviewed the project and determined that costs had ballooned so high that the project had to be shelved.
Proposals by the Ramos and Arroyo administrations
After the administration of President Fidel Ramos took over in 1992, it continued conducting studies for the development of a Dam in Laiban, but these remained just proposals as he Metropolitan Waterworks and Sewerage System was privatized, and concessionaires Manila Water and Maynilad took over the servicing of water in the National Capital Region.In 2007, the administration of Gloria Macapagal-Arroyo was able to get funding for the Laiban Dam approved. But the ZTE broadband scandal broke, and the project, which would have been funded using China state loans, was once again shelved.
2009 San Miguel Corporation proposal
In 2009, San Miguel Corporation submitted an unsolicited proposal for the building of a dam in Laiban, but public opinion at the thought of higher water rates led to the project once again being shelved in 2010.2009 Kaliwa Intake Weir proposal
Also in 2009, Osaka-based Japanese company Global Utility Development Corporation submitted an unsolicited proposal for what was called the Kaliwa Intake Weir Project, which would have seen the creation of a 7 meter,550 MLD Weir at the Kaliwa site, instead of a Dam. At the instructions of President Aquino, this proposal was explored again in 2017, after the approval of the New Centennial Water Source-Kaliwa Dam Project by NEDA. However, it was later dismissed in favor a China-loan-funded dam project in 2019.Kaliwa Low Dam Proposal under the Benigno Aquino III administration
The New Centennial Water Source-Kaliwa Dam Project was a water project proposed by the Philippine Government in 2012, whose main component was the construction of the Kaliwa Low Dam in Tanay, Rizal, as well as a water supply tunnel, and the attendant infrastructure for these structures. The proposed Kaliwa Low Dam design had a 600 million-liters-a-day capacity, and the water supply tunnel has a 2,400-MLD capacity. Had it been built, the Kaliwa Low Dam was expected to ease the demand on the Angat Dam, Manila’s sole water storage facility.The project had originally been proposed as a bigger, integrated system which included a plan for a second dam, named Laiban dam further upstream. But the government decided on a proposal which would have built the system in stages, and only stage one, involving Kaliwa Low Dam and the water supply tunnel, were approved under the administration of Benigno Aquino III.
In 2015, two consortia were pre-qualified to bid for the undertaking of the Kaliwa Dam project — the SMC-K Water Consortium, which is a partnership between San Miguel Holdings Corp. and Korea Water Resources Corp.; and the Abeima-Datem Consortium, which is a partnership between Albeinsa Infraestructura Medio Ambiento S.A and Datem Inc.
When the project did not move forward by the time Aquino administration ended, the succeeding Duterte administration decided not to pursue the Japanese-proposed Kaliwa Low Dam plan and instead pursued a bigger, China-funded dam project.