But West Service Area water supply volatile until October 16
By Mike Baños
Delivery of the contracted bulk water supply by Rio Verde Water Consortium Inc. (RVWCI) to the Cagayan de Oro City Water District (COWD) resumed noon last Saturday, 07 October 2017 with a continuous flow rate of 1,700 cubic meters per hour (cmph), or not less than 40,000 cu.m. per day (m3/day).
However, as earlier discussed during the City Council Committee on Public Utilities public consultation held last Thursday, 05 October 2017, the COWD already needs at least 60,000 m3/day to normalize water supply and pressure to concessionaires in the West Service Area.
But Rio Verde said it will only be ready to deliver the additional volume over the contracted daily volume of 40,000 cu.m. starting Monday, 16 October 2017. Thus, water supply in the affected areas would still continue to be limited for another eight days.
Engr. Joffrey E. Hapitan, Rio Verde Vice President, said they can only supply the additional volume of bulk water needed by the COWD in the West Service Area once repairs are
completed on its main 650mm submarine water supply pipe damaged by the recent spate of earthquakes and river debris propelled by floods driven from torrential rains
“Construction of the cofferdam is in progress and welding and repair of Rio Verde’s main 650 mm main water supply pipe will commence Wednesday, 11 October 2017 with an estimated time of completion on Sunday, 15 October 2017,” Hapitan said in a text message to this writer.
“Rio Verde will be ready to supply additional volume up to 60,000 m3/day or more starting Monday, 16 October 2017 onwards,” he added.
In an advisory posted on its official website 9:00 am 07 October 2017, the COWD confirmed RVWCI has just resumed supply to COWD’s off-take point with a flow rate of 1,500 cubic meters per hour (cmph) and a pressure of 23 pounds per square inch (psi).
“While this is an improvement from the time when pressure was about 4 to 5 psi, low pressure to no water will still be experienced in the west area. Water delivery will continue to be facilitated. Water from COWD sources is safe. However, due to circumstances that may happen during transport, handling and storage, boiling water for drinking is advised.”
A follow-up post at 1:00 pm on the same day said “RVWCI’s minimum flow rate to COWD Off-Take Point is now 1,700 m3/hr or 40,000 m3/day. Without the desired pressure though, customers in elevated areas and those in the farthest end will still experience low pressure to no water. Water delivery shall be concentrated to those areas.”
“Meanwhile, construction of Rio Verde’s Cofferdam is also in progress. Welding/Repair of underwater pipe will commence Wednesday next week, ETC: Oct 15. According to Engr. Hapitan, Rio Verde will be ready to supply 60,000 m3/day or more starting Oct 16 onwards.”
Earlier Friday, Hapitan confirmed during a noon time meeting with COWD technical staff that Rio Verde had installed and is commissioning a brand new unit of 650 KW Booster Pump costing P6.0 million.
“This booster pump is responsible in creating higher pressure of water from the Rio Verde Water Treatment Plant in the ‘smaller diameter emergency line’ (HDPE) that is being utilized today to attain 40,000 cubic meters per day flow rate at COWD take off point,” Hapitan explained.
Unfortunately, the higher pressure caused leaks along Rio Verde’s main pipeline from the treatment plant to the HDPE back-up pipeline and bulk water delivery had to be suspended and the booster pump shut down while the leaks were repaired.
Hapitan requested the COWD Production Dept. headed by Engr. Edward Tesoro to lower their required residual pressure at the off-take point to 20 psi to enable Rio Verde to lower the operating pressure of the booster pump from 300 psi to 250 psi to prevent further leaks from recurring.
Data provided by Rio Verde to this paper reveals the flow rate delivered by Rio Verde to COWD ranged from 1,829 m3/hr at 1200 noon to 2,158 m3/hr by 05:00 pm Friday.
But Tesoro said while COWD confirmed receiving a flow rate of 1,802 m3/hr at the off-take point (TOP), it was not at the specified pressure. “The pressure at the TOP is zero,” Tesoro said in a text message to this writer.“There will be an improvement in lower service areas, but Palalan and Lumbia will have no water. Delivery through water tankers is still the immediate solution thereat.”
Hapitan confirmed that they need not maintain a residual pressure since Rio Verde wanted to prioritize higher flow rate to ensure delivery of the contracted 40,00 M3/day volume.
Tesoro said they needed a residual pressure of at least 70 psi at the TOP to be able to service elevated and farthest areas. COWD has a standby in-line booster at TOP to pump water up to Lumbia area in case pressure drops to 55 psi while other elevated and farthest areas remain unserviced.
However, Hapitan said they could only provide 70 psi without their online booster at the off-take point by Monday, October 16 or in eight days when Rio Verde completes repairs and commissions back its 650mm submarine main transmission line in the Cagayan River.
Meantime, Hapitan said Rio Verde would complete construction of a redundant 650mm back-up transmission line which can withstand a Magnitude 8 earthquake like the rehabilitated main line to prevent another occurrence of the present water shortage in COWD’s West Service Area.
Hapitan said each of the two 650mm main submarine transmission lines can deliver up to 100,000 m3/day of treated bulk water to COWD, which is the present rated daily capacity of its water treatment plant in Baragay Pualas, Baungon, Bukidnon.
Rio Verde can still expand the present plant by another 50,000 m3/day of treated bulk water to attain its designed daily capacity of 150,000 m3/day.
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