Banica River, one of the major sources of domestic water in Dumaguete City, needs protection from any type of pollution and exploitation, said biologist Dr. Esther Carumbana, lead researcher in a study on Water Quality and Aquatic Biodiversity Relative to the Socio-Economic Conditions in the Banica River, Negros Oriental.
Banica River which stretches approximately 35 kilometers from its headwaters to the sea, carved and molded the hydrologic landscape of Dumaguete City as well as the towns of Valencia and Bacong where it traversed, said Carumbana.
Rivers are potential factors that contribute to economic development. Negros Island is gifted with river systems extending from the north to the southern end of the two provinces, Negros Oriental and Negros Occidental. Banica River is favorite place for laundering, bathing, washing of dishes, as source of firewood, garbage disposal or deposition, and as source of sand and gravel for construction.
Way back in the early 1900s, Carumbana said, Banica River was used by the local population for washing, bathing, growing “kangkong” and other indigenous plants; and, was also a habitat for many species of fish, mollusks and crustaceans, particularly shrimps.
However, with the advent of modern technology and the rapid increase in population, coupled with increasing demands for space, Banica River has been transformed into a filthy drainage canal, especially during the summer months.
This claim is primarily based on Dr. Carumbana’s terminal report of the study on water quality and biodiversity. A multi-disciplinary study, it was funded by Negros Oriental State University Research Extension & International Linkages. Other multi-disciplinary results are still on process. Co-researchers of the study include Professors Evangeline Gajunera, Eduardo Iso, and Dr. Noel Yasi.
On biodiversity in the Banica River, the report stated that the physico-chemical characteristics of the water are favorable for growth and survival of fish and crustaceans, but there is scarcity and low diversity of these organisms — these may be attributed to the use of electricity (electro-fishing) by local fishers.
In a recent interview with Dr. Carumbana, she explained that the fishers would get electricity from batteries used in vehicles such as truck, van, jeep, easy ride, or even motorcycle; and this type of fishing is still done in upstream and midstream from close to midnight or at dawn when the weather is fine.
Aside from being illegal, the report noted that electro-fishing is very destructive because it could kill all species of aquatic organisms, especially the plankton which is the primary source of food in the water as well as the eggs of fish and crustaceans.
Carumbana said the small sizes of the fish, shrimps, crabs and mollusks that were collected indicate that the resources are overexploited. Concerning salt level, the study described that the salinity of the water upstream and midstream is typically that of freshwater while the salinity downstream varies, due to intrusion of sea water being located adjacent to the mouth of the river.
Majority of the people living along Banica River made use of the river and its resources in different ways for which they should be monitored to prevent further deterioration of the river ecosystem. The report stated that some of the respondents disposed of their animal or agricultural wastes directly into the river while others just left them unattended and allowed them to decompose and mix with the soil.
This is alarming, according to Carumbana, since the polluted soil will become eroded and eventually enter the river, thus enhancing contamination and hastening deterioration of the river quality; and, due to unavailability of the proper drainage systems, the sewage water coming from various households is directly drained into the river.
Carumbana stressed that the occurrence of floods brought about by typhoon Sendong in December 2011 wiped out practically all organisms in the river.
The study was done in September 2011 to March 2012. To involve households along the banks of the river, 150 residents were interviewed. Biological parameters included sampling for fish, sampling for crustaceans, benthos or animals inhabiting the riverbeds including mollusks, and sampling of water for coliform analysis which showed high density of total coliform bacteria. The density of coliform bacteria was highest in November in upstream and downstream, Valencia and Tinago in Dumaguete, respectively.
To improve and prevent further worsening of the river’s present ecological status, the researchers have recommended that the residents in cooperation with local government units should exert efforts and initiatives to implement proper method of deposition and collection of solid wastes. Needed collaborative actions are to stop illegal fishing in the river and encourage massive tree planting along the river banks.
Most importantly, here is a need to intensify dissemination of information in the communities regarding environmental awareness and conservation. (Joy Perez, SU Research & Environmental News Service)
