Text and Photo by Henrylito D. Tacio
It may be invisible, but its impact is visible everywhere. That’s what groundwater is all about.
“Out of sight, under our feet, groundwater is a hidden treasure that enriches our lives,” says the United Nations. “Almost all of the liquid freshwater in the world is groundwater. As climate change gets worse, groundwater will become more and more critical. We need to work together to sustainably manage this precious resource.”
Groundwater may be out of sight, but it must not be out of mind. Next month, the world observes World Water Day. This year’s theme is apt: Groundwater – Making the Invisible Visible.
Held on March 22 every year since 1993, World Water Day takes action to tackle the water crisis. It raises awareness of the 2 billion people living without access to safe water.
An extensive report from Greenpeace, “The state of water resources in the Philippines,” said the country obtains its water supply from various sources. These include rainfall, surface water resources (that is, rivers, lakes, and reservoirs), and groundwater resources.
“Groundwater is fresh water that soaks into the soil and is stored in the tiny spaces (pores) between rocks and particles of soil,” explains the US Environmental Protection Agency (EPA). “It can stay underground for hundreds of thousands of years, or it can come to the surface and help fill rivers, streams, lakes, ponds and wetlands.”
The country has an extensive groundwater reservoir with an aggregate area of about 50,000 square kilometers. (The Philippines has a total land area of 30 million hectares.) The four major groundwater reservoirs are in Cagayan, Central Luzon, Agusan, and Cotabato.
According to the Mines and Geosciences Bureau (MGB), a line agency of the Department of Environment and Natural Resources (DENR), several groundwater basins are underlaid by about 100,000 square kilometers of various rock formations.
These groundwater resources are located in: Northeast Luzon, Central Luzon, Laguna Lake basin, Cavite-Batangas-Laguna basin, Southeast Luzon, Mindoro island, Negros island, Northeast Leyte, Ormoc-Kananga basin, Agusan-Davao basin, Occidental Misamis basin, and Lanao-Bukidnon-Misamis basin.
Based on data from Philippine Environment Monitor (PEM), Cagayan Valley has the highest potential source of groundwater with 2,825 million cubic meters (MCM). Eastern Visayas trailed with 2,557 MCM then Southeastern Mindanao (2,375 MCM) and finally Northern Mindanao (2,116 MCM). Centra Visayas has the least potential source with only 879 MCM.
Groundwater is used for drinking by about 50% of Filipinos. Based on the water rights granted by the National Water Resources Board since 2002, 49% of groundwater is consumed by the domestic sector, and the remaining is shared by agriculture (32%), industry (15%), and other sectors (4%).
The PEM, published by the World Bank, stated that about 60% of the groundwater extraction is without water-right permits, resulting in indiscriminate withdrawal. A high percentage (86%) of piped-water supply systems uses groundwater as a source.
Like surface water, groundwater is also susceptible to pollution. “Pollution of groundwater may come from domestic wastewater, agricultural runoffs, and industrial effluents,” PEM reported.
The presence of coliform bacteria in drinking water supplies can cause water-borne diseases. The Water Environment Partnership in Asia (WEPA) said up to 58% of groundwater sampled in a study were found to be contaminated with coliform and needed treatment. Approximately 31% of illnesses monitored for a five-year period were caused by water-borne sources.
A senior environmental specialist from the World Bank said the lack of proper sewerage systems has led to the contamination of groundwater. “More money must also be invested in the sewerage system because untreated water is costing everybody’s health and even the tourism industry,” he said.
It must be recalled that in early 2006, human waste contamination in the water supply caused the diarrhea outbreak that claimed the lives of three persons and downed 369 in Bohol. Three years previously, more than 500 residents in Tondo, Manila, were rushed to various hospitals due to a cholera outbreak; five others died.
Another problem is saline water intrusion, which is caused by over-exploitation or excessive withdrawal of groundwater. This reduces water availability for domestic usage, including drinking and agricultural usage.
Climate change and population also play an important role in the use of groundwater. “The influence of climate and population change will have an acute impact on groundwater,” said a study of the UK Research and Innovation in its Philippines Groundwater Outlook.
“Groundwater is strategically and economically important to current and future water supply and is the principal source of dry season river flows, which in turn are often used for potable supply,” the study said.
Dr. Sandra Postel, director of the Massachusetts-based Global Water Policy Project, believes water problems will be right there with climate change as a threat to the human future, and global warming will worsen water problems.
“Although the two are related, water has no substitutes,” she explains. “We can transition away from coal and oil to solar, wind and other renewable energy sources. But there is no transitioning away from water to something else.”
Only 2.5% of the water that covers over 70% of the earth’s surface is considered freshwater. And only 1.3% is available for human use since most of the freshwater is trapped in glaciers, ice sheets, and mountainous areas.
“Water is the most precious asset on Earth,” says Dr. Postel.