Saturday, December 20, 2008

The Pampang Water Control System

To describe the irrigation and hydraulic engineering system, I will use information gleaned from my father, who along with his family during World War II relocated to relatives' farms in the boondocks of Masantol. Many of the graphics are taken from the following article:

Adams, Wallace, Heraclio R. Montalban and Claro Martin. "Cultivation of bangos in the Philippines," The Philippine journal of science Vol. 47, no. 1, Manila, 1-38.

The pampang or dikes that divert water are made of piled up earth or mud. These dikes are generally low except near the more powerful rivers.

Pampang near the river are usually planted with mangroves or Sonneratia trees to help them withstand the force of the tides and floods. These dikes are usually very wide and roads were constructed on them. Both the Spanish and Americans improved upon these pampang roads. Juan de Medina writing in 1630 states:

All Pampanga is like streets, for the houses of one town are continued by those of another. One may go to all its towns without getting in the sun, for now the bamboos, and now the palms furnish very pleasant shade.

The mangroves not only protect the dikes, but also act as environments for talangka crabs and other species,which are harvested by farmers. The small dikes that demark the rice fields and fish ponds are generally kept free of vegetation and contain foot paths.

Tidal and sluice gates are known as saplad in the Masantol area. These days the main gates along the river are generally constructed with concrete. In former times, they were made of stones or bricks cemented together or of thick, sturdy hardwood. The saplad are sliding gates with handles on top. Farmers pull up the gate and then place stops into slots in the gate door to hold it into position. Drainage is afforded by ditches known as bangbang.

Water is allowed into the ricefields by smaller gates which are actually tiny dams known as tambun or tambunan made of mud and straw. The farmer simply cuts a little channel into the dam to let water in, and reconstructs the dam to keep water from draining out.

Fish ponds or kaluangan

The fish ponds are a bit more complicated in construction as they hold more water and require a certain directed flow of water. These fish ponds are based on pisiculture of bangus (milkfish) or related species like the Pacific tarpon. The exact origins of milkfish culture is unknown but it was practiced when the Spanish first came to these islands.

These fish are saltwater species but migrate as fry to brackish water estuaries and mangrove swamps were they mature, and then return as adults to the sea. Fish ponds are best made in areas of clay soil or the ponds are lined with clay, which retains water and also is the best soil to produce vegetation that bangus like to feed on.

The dike is built above high tide and flood level with a puddle trench (mecha) below in an appropriate tidal estuary. The main gate or saplad allows water in from the river.

Gate system of a pampang fish pond for raising bangus and related salt/brackish water species.

The ponds used to grow the fish from fingerling to adult size are generally divided into sections known as kulungan (catching pont), impitan or bansutan (containment pond) and kaluangan (rearing pond). A series of smaller gates directs the flow of water in a circular fashion.

The fish pond system with subdivisions.

A separate type of pond is used for raising bangus fry known as pabiayan. The pabiayan also have a kulungan catching pond that is fed by a canal known as sangka. Pipes known as pansol usually made of anahaw wood circulate water into the rearing ponds.

k' - kulungan; p' - pansol; sg - small wooden gate; qp - quadrangular pipe.

Water in both fish and rice ponds is usually freshened at least twice a month during the lunar high tides that occur around the New and Full Moons. Both fish and rice culture in the pampang system involve initial raising in one location, and then transplanting to another location for maturation.

The saplad gates are left open during the high tides and are closed during ebb tides to prevent water from draining back in the estuary. Knowledge of the ebb tide is important and probably many today simply use modern tide predictions, but in ancient times an indigenous system was employed, which in itself would be an interesting area of research. Antonio de Morga writing in 1609 describes the difficulty of predicting tides in some of the southern areas of the Philippines.

The flow- and ebb-tides, and the high and low tides among these islands are so diverse in them that they have no fixed rule, either because of the powerful currents among these islands, or by some other natural secret of the flux and reflux which the moon causes. No definite knowledge has been arrived at in this regard, for although the tides are highest during the opposition of the moon, and are higher in the month of March than throughout the rest of the year, there is so great variation in the daily tides that it causes surprise. Some days there are two equal tides between day and night, while other days there is but one. At other times the flow during the day is low, and that of the night greater. They usually have no fixed hour, for it may happen to be high-tide one day at noon, while next day high-tide may be anticipated or postponed many hours. Or the tide of one day may be low, and when a smaller one is expected for next day, it may be much greater.

The Bugis of Sulawesi possess a sophisticated algorithm for predicting tides and it would be interesting to see if the Pampangan system is similar.

Paul Kekai Manansala