The town of Tarlac is situated about half-way between the two bays, and approximately marks the watershed. About half-way between Tarlac and the northern shores of Manila Bay there rises from the plain an isolated mountain of volcanic origin, Mount Arayat. The crater has been split through and the mountain thus shows two peaks. It is covered with forest to the very summit. Arayat was thrown up within historic times, and the Indians have a tradition that it was completed in one night, which is a most unlikely story.
Mount Arayat is 2880 feet in height, and in fine weather is plainly visible from Manila and Cavite, and even from the mouth of the bay.
The principal rivers of this valley are the Agno, the Dagupan, the Rio Grande and the Rio Chico of Pampanga.
The Agno rises in the mountains of Lepanto, runs south through the province of Benguet, and S.W., W. and N.W. in Pangasinan into a labyrinth of creeks communicating by many mouths with the Bay of Lingayen. The river between Dagupan and San Isidro is navigable for vessels drawing seven or eight feet, and such craft could reach Salasa. From there to Rosales only lighters of very small draught could pass, and after a long spell of dry weather rice-boats drawing only one foot sometimes run aground. Its principal tributaries are the Tarlac and the Camiling, with dozens of smaller streams bringing the whole drainage of the eastern slopes of the Zambales mountains from Mount Iba to San Isidro.
The Dagupan river rises in the mountains about the limits of Union and Benguet and runs parallel to the Agno to 16° N. lat., and between it and the sea. Then it turns to the westward, and runs past the towns of Urdaneta, Sta, Barbara, and Calasiao, entering the Bay of Lingayen at Dagupan. It has a multitude of small tributaries which are very differently shown on D’Almonte’s and Olleros’ maps, and undoubtedly this part has never been surveyed.
The Pampanga river has its source on the southern slopes of the Caraballo, in about 16° 10′ N. lat. It runs south in two branches, the Rio Grande and the Rio Chico; the first, being the easternmost, receives the drainage from the western slopes of the Cordillera del Este, whilst the Chico receives tributaries from both sides in the flat country and also the overflow from the Lake of Canarem.
These two branches unite just north of Mount Arayat, and continue in a southerly direction. The river is navigable for small craft drawing three feet as far as Candaba in the dry season, and in the rainy season as far as San Isidro in Nueva Écija. When in flood during the rainy season, this river brings down a large body of water and annually overflows its banks in certain places, where gaps occur. The escaping water spreads itself over a low plain forming an inundation some sixteen miles long and several miles wide, called the Pinag de Candaba. This remains during the rainy season, and when the level of the Rio Grande has fallen sufficiently, the water of the Pinag commences to fall also, and during the middle and latter part of the dry season, and the beginning of the rainy season, only patches of water remain here and there, which are utilized for breeding fish, and a crop is raised on the land left dry. A project for draining the Pinag and reclaiming the land was many years ago got up by a Spanish colonel of engineers, and, at the request of an English company, I went up to investigate and report on it. I found that, irrespective of the difficulties and expense of the proposed works, the vested rights of the natives of the many towns and villages in and around the Pinag rendered it impossible to carry out the scheme.
Vast flocks of wild duck and other water-fowl frequent the Pinag, and good sport is to be had there. Below the Pinag the river spreads itself over the low country, forming a labyrinths of creeks mostly navigable for craft drawing three to four feet, but the mouths are all very shallow and the bars can only be crossed about high tide. The water is brackish or salt. An immense extent of country is intersected by these creeks, certainly 200 square miles, and there are said to be 120 mouths connecting with the bay. With the exception of two or three of the principal channels, this swamp has never been surveyed, and what is shown on the map is merely guessed at. The muddy soil is covered with mangrove in the low parts submerged at each tide, and with the Nipa palm where the banks rise above high water. Under the heading Pampangos will be found particulars of the manufacture of nipa-thatch carried on here, and of collecting and distilling the juice. With the exception of a few half-savage natives the only living things are wildfowl, fish in abundance, alligators, snakes, and blue crabs. This is indeed a great dismal swamp, more especially at low tide.
It is difficult to find one’s way in these creeks, and although I frequently traversed them, I found it necessary to take a swamp Indian as a guide.
The city of Manila is situated astride the River Pasig on a strip of land between the Bay of Manila and a great sheet of freshwater called the Lake of Bay. In consequence of this situation, Manila can communicate by the bay, the lake, the creeks and rivers with the provinces of Bataan, Pampanga, Nueva Écija, Bulacan, Morong, Laguna, and Cavite. Until the opening of the Manila-Dagupan railroad the whole transport of the Archipelago was by water, and the possession of navigable rivers meant progress and wealth, whilst the absence of rivers meant stagnation and poverty. Around the city the land is quite flat, but at about four miles distance there is a sharp rise to a plateau of volcanic tuff, the surface of which is from sixty to eighty feet above sea level, of which more anon. The River Pasig is the overflow from the lake and the outlet for the River San Mateo, which runs into it at right angles. The lake serves as a receiver for the great floods that come down the San Mateo valley; for the level of that river at Santolan, the intake of the waterworks, sometimes rises more than twenty feet. When this occurs, the flood on reaching the Pasig is divided; part runs into the lake, and part into the bay. The current of the Pasig in that part between the junction of the San Mateo and the outlet from the lake is reversed. Then when the flood subsides, the water which has entered the lake runs out very slowly into the bay, for the head produced by the greatest flood becomes insignificant from being spread over the vast extent of the lake.