Virac Water District draw water from three open sources: “Cawayan”, “Padurog” and “Sibanjan” rivers, all located within the Watershed Protection Forest (WFR), north of the Virac poblacion.
The Cawayan water source has the largest catchment at 13.3 sq-km. with a potential discharge of 60 liters per second (lps). It has an elevation of 183 meters msl. Built in 19xx and originally designed to service 800 households (HH), it currently has 2,500 connections from 12 barangays north of the town center.
The source’s slow sand filter was built without the provision for backwashing and since has suffered from lack of proper maintenance. A new rapid sand filtration system, which is estimated to cost roughly PhP 8-M, has been completed and is now partly operational.. The facility includes flocculation and sedimentation structures designed to address the turbidity situation. Raw water is passed through various filtration media of activated carbon, silica sand, and gravel layers, then stored and disinfected using a hypochlorinator before transmission and distribution.
Sibanjan at 4.42 sq-km is the second largest among the three water sources, and Padurog is the smallest at 2.72. The use of these two water sources predate Cawayan and has been in continuous operation for almost three decades and currently still have some asbestos pipelines. Sibanjan has both open and spring sources and is equipped with a slow sand filtration but lacks a backwashing structure. Chlorination is by injection. Because of its spring water, concessioners connected to it enjoy lesser turbidity problems. Padurog has the smallest catchment and provides roughly only 35 lps of discharge. Because its intake structure has been continually damaged by recurring typhoons, its discharge water is comparatively the most turbid (see technical data).
VWD also abstracts water from two ground sources, used sparingly during the dry months. Both are equipped with submersible pumps. The smaller is located in the West Garden Subdivision with a capacity of 7.5 lps. While the other has a 15-lps capacity located inside the campus of the Catanduanes State University (CSU). Ensuring the safety of the structures and the water produced is one concern being addressed.
The third groundwater identified source is still to be tapped, although it has a proven capacity estimated from 10-20 lps. The area of possible drawdown is located within the provincial capital compound.
Technical Data
| Water Source | Cawayan | Padurog | Sibanjan |
|---|---|---|---|
| Intake Structure Type | Concrete Box | Concrete Box | Concrete Box |
| Elevation | 183 meter above msl | 277 meter above msl | 210 meter above msl |
| Intake Production | 48 Ltr/sec. | 35 Ltr./sec | 30 Ltr./sec |
| Watershed Area | CWFR (13,3 sq-km) | CWFR (2.72 sq-km) | CWFR (4.42 sq-km) |
| Soil Type | Conglomerate, Limestone | Limestone, Calcaretine | Limestone, Calcaretine |
| Slope characteristics | Stiff Slope to Medium Shape | Stiff to Medium Slope | Stiff to Medium Slope |
| Vegetation | Forest | Forest | Forest |
| Human settelements | None | None | None |
| Agricultural activities | Abaca Farming | Abaca Farming | Abaca Farming |
| Industrial Activities | None | None | None |
| WQ Characteristics | |||
| Clear | Clear | ||
| None | None | ||
| None | None |
Resource Constraints
Turbidity, inefficient intake structure, transmission problems and ageing distribution pipelines.
Because surface water is prone to all sorts of contamination, VWD has to face intermittent bouts of turbidity for lack of adequate pre-filtration structures to ensure that that water supply is safe for household use. This particular situation becomes a regular problem, especially during rainy months, occurring almost three quarters of the year. The installation of structures to address this condition is now being put in place, hopefully cutting significantly treatment expenses.
Ageing system – repair and replacement of remaining asbestos transmission and distribution pipes; for upgrading. Remaining asbestos pipes due for replacement. Maintaining the physical infrastructure in tip-top condition is also a major problem given the prevailing weather conditions obtaining in a type-II climate area. Regular repairs are eating much of the District’s MOOE budget.