Surface Water key to COWD’s sustainability

Mar 31, 2018

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Unless Cagayan de Oro City shifts to sourcing its potable water supply from underground to surface water, it would sooner or later face a water crisis even worse that what some areas are now experiencing.

COWD pumping station damaged by TS Vinta last Dec. 22, 2017

COWD pumping station damaged by TS Vinta last Dec. 22, 2017

 

That’s because the groundwater on which the Cagayan de Oro Water District (COWD) now sources 80% of its water is fast depleting, and the Local Water Utilities Administration (LWUA) wants all water districts under its purview to stop drilling for new ones by 2030.

A 2003 study on water abstraction from Cagayan de Oro strongly indicates that the city’s aquifers are being severely depleted beyond their ability to recharge.

Even with three major watersheds supplying five major rivers and creeks, the research conducted by Rosalina Palanca-Tan, with Germelino Bautista, from the Institute of Philippine Culture, Ateneo de Manila University, Quezon City found the city had no surface source of water, with the area’s rivers and streams devoted for other purposes, such as irrigation.

The study showed that Cagayan de Oro’s daily abstraction rate in 2003 (i.e., 15 years ago) at 114,000 per cubic meters against a water replacement rate of its aquifers of only 94,000 cu.m. resulting in a daily loss of 20,000 cu.m. a day or 7,200,000 cu.m. a year. Thus, an estimated 108-million cu.m. of water would have been depleted from the city’s aquifers in the interim.

The study found that many of the city’s 8,500 registered businesses, fully 65 percent had not COWD water connections, choosing instead to dig their own artesian wells, mostly without permits from the National Water Resources Board (NRWB). These industrial and institutional users composed one-third of the total daily ground water withdrawal.  

Rising demand depleting aquifers

In a presentation held during World Water Day last 22 March 2018, COWD Acting General Manager Bienvenido V. Batar, Jr. disclosed the water district’s current daily abstraction rate is now 146,290 cu.m. , a 28% increase over the last 15 years despite sourcing 40,000 cu.m. of bulk water daily from the Rio Verde water treatment plant in the last 11 years.

Cagayan de Oro Volunteer Fire Brigade distributes water to residents in Bgy Kauswagan in the aftermath of TS Sendong, Dec 2011.(RMB)

Cagayan de Oro Volunteer Fire Brigade distributes water to residents in Bgy Kauswagan in the aftermath of TS Sendong, Dec 2011.(RMB)

 

“Our present supply from all sources is just enough to meet demand,” Batar said. “If any of our wells go down for repairs, it would immediately result to disruptions in water service.”

Although drilling new wells to tap the city’s depleted would be the quickest way to address the rising demand for water, both the LWUA and COWD say this is unsustainable.

“Wells pose a big problem,” admitted Eduardo Montalvan, chairman of the COWD Board of Directors. “That’s why we being dependent on wells, we have a big problem. Even if we use submersible pumps, we are still vulnerable. If only one well goes down, a big area instantly affected.”

In the last seven years, floodwaters spawned by tropical storms and typhoons badly damaged the COWD’s pumping stations in 2011, 2012 and 2017.

“After we were hit by Sendong, it took us over a month to recover and resume normal operations since some of our pumps were flooded and contaminated. We had to repair and recondition the pumps,” Montalvan noted. “Although Vinta did not inflict as much damage, it still took us 10 days to recover. The problem is still there, and we’re still trying to do something about it. Hopefully we can finally solve that if we can look into surface water supply.”

Groundwater moratorium

 “LWUA and COWD will both protect environment, start exploring development of further surface water sources by 2020 and completely stop all groundwater drilling and development by 2030, “Batar said.

The bulk water supply which COWD has been buying from Cagayan de Oro Bulk Water, Inc. (COBI) since January, 2018 accounts for 21.47% of the total COWD daily production for COWD’s East and West service areas.

This volume is projected to rise as soon as repairs to the bulk water treatment plant are completed to 60,000 cu.m. daily until 2019, when it is slated to rise to 80,000 cu.m. daily, and thence to 100,000 cu.m. daily starting 2022.

But even if the present treatment plant is maxed out at its rated production capacity of 150,000 cu.m. of treated water daily, this would still be insufficient to meet the city’s rising demand for potable water, hence even now COWD is already considering other surface water sources.

“Yes we are looking at Cagayan River,” Montalvan revealed. “But we are still exploring how to exploit it since it has many issues like where do we put the treatment plant?”

Official Development Partners like USAID are helping COWD plan for the future.

“There was a feasibility study financed by USAID,” Montalvan disclosed. “They came here with a big local company asking If they could already implement it, and they’re looking at the feasibility of a surface water supply.”

The Big Picture

The National Water Resources Board (NWRB) estimates total available groundwater supply to be 20,200 million cu.m. per year. Based on an 80% probability for surface water, the total dependable surface water supply is 206,230 million cu.m. per year, implying a total mean supply of 226,430 million cu.m. per year.

Murky water from water taps is a common complaint by water consumers since most  of COWD's water supply is sourced from groundwater (photo supplied)

Murky water from water taps is a common complaint by water consumers since most of COWD’s water supply is sourced from groundwater (photo supplied)

 

Agricultural use accounts for 83% to 85% of this amount, the remainder being shared by the industrial, commercial, and domestic sectors.

Growing population especially in the urban areas together with water pollution, wasteful and inefficient use, continued denudation of forest cover (particularly in watersheds), and saltwater intrusion caused by excessive withdrawal of groundwater (particularly in the metropolitan area of Cebu, Davao City, and certain areas of Metro Manila), are the major challenges facing the country’s water resources. (ADB, 2016)

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