Low in chemicals, high in coliform

Water quality monitoring of Davao River shows

DAVAO River still conforms to the water quality guidelines except coliform content, a watershed official said.

Water Quality Management Areas (WQMA) Unit Head Ma. Socorro Mallare said yesterday, during the Watershed Stakeholder Summit 2016 that in terms of Dissolved Oxygen, Biochemical Oxygen Demand (BOD), potential hydrogen (pH) and Temperature, Davao River has passed all the measures for Class A and B in a series water quality monitoring conducted last year. But samples taken from all 17 stations did not meet the water quality guidelines for Total Suspended Solid (TSS) and total coliform.

According to her, the water quality has different classification. The Class A: Public Water Supply Class II means that sources of water supply that will require complete treatment in order to meet the NSDW while Class B: Recreational Water Class I is for primary contact recreation such as bathing swimming, skin diving.

“In terms of the parameters we have monitored, all the parameters excluding the TSS and coliform are still in good state pa rin. Yon nga lang hindi mo masabi na ang kabuuhan ay maganda kasi may dalawang bumagsak,” Mallare said.

The total coliform, which used as criteria the degree of pollution and sanitary quality of water source, is alarming since the health of the people is at stake. The sources of coliform bacteria include domestic and industrial wastewater discharges, septic tanks, and domestic and farm animals.

On the other hand, one of the cause of high level of TSS upstream are attributed to the existing-large scale sand and gravel quarry operations and erosion of soil.

“Mataas na rin ang TSS kasi yong soil erosion ng mga gilid-gilid ng river,” Mallare added.

This trend will likely

continue if the quarry operations of sand and gravel, considered as the primary factors, will go on, she said.

Mallare, based on her presentation, said that the downstream portion of the river is heavily silted such that during heavy rains the silts are re-suspended causing the water to be very turbid. Soils are also eroded during heavy rains through surface run-off.

Therefore, they recommended the strict implementation of The City’s Septage and Sewerage Ordinance, Building Code particularly on the provision of 3 chamber septic tanks in residential and commercial establishments not only those loThe cated along the river bank; and Ecological Solid Waste Management.

She also emphasized the planting of many trees along the riverbank and on gullies to prevent soil erosion. The Local Government Unit (LGU) regulation/monitoring on the sand and gravel quarry in Davao River.

In maintaining the quality of Davao River, monitoring should be continued in order to determine the possible causes of pollution and the actions that can be possibly undertaken to address said causes.

“Davao River is designated as WQMA kaya nga maraming mga programa tayo na pinapatupad para matulungan ang pag protect sa water quality,” Mallare said.

Based on the results, there is a need protect the watersheds to ensure the quality of water supplies.