Topography and Slope
The topography of Guiguinto is generally flat. Slopes are in the lowest category or the 0 - 3% range. The highest elevation is at 7 meters ASL and located at Barangay Pritil on the northern part of the municipality. The lowest elevations are in Barangay Panginay with elevations barely above sea level. The north and northeastern portions of the municipality are generally higher than the rest of the area. In essence, the relatively flat topography of the area caters to the development of agriculture. It has also aided is the classification of the municipality as low-risk in terms of erosion hazards. However, Barangay Panginay in the south is a potential flood-prone area being almost at level with Manila Bay
Implications to the Municipality of Guiguinto
Records and observations from these two important habitats that lie north and northeast of the municipality suggest the presence of congregatory wildlife such as birds that are endemic to Luzon. Most of these species of wildfowl often use Candaba Swamp and Angat Watershed as staging and wintering grounds in certain times of the year. There are species of wildlife that are classified as having restricted range and cover areas that may include the municipality of Guiguinto and its surrounding environs. However, with no habitats to support these restricted range species, the municipality may be a transit point to and from the important habitats of Candaba Swamp and Angat Watershed.
The Philippine archipelago is divided into four (4) physiographic provinces. The Province of Bulacan belongs to the Central Physiographic Province. It is composed of cordilleras, lowlands, troughs and offshore basins. It is also subdivided into six (6) sub-provinces. Guiguinto belongs to the Central Luzon Basin. This basin is occupied by sediments ranging in age from Miocene to Pliocene, which have undergone subsidence and uplift.
The Central Luzon Sub-province is composed of Luzon Central Plain, Southwest Luzon Uplands and the eastern lowlands of Mindoro. It is also the largest plain in the country, found between the Zambales Range and Sierra Madre. It opens into Manila Bay on the south and Lingayen Gulf on the north. The plain is 150 km long with an average breadth of 60 km. Mt. Arayat at 1030m elevation ASL, a lone volcanic peak, stands prominently in the center of the plain. In the northeastern part are Mounts Amurong, Balungao and Bangcay. Agno River drains the northern part of the plain and empties into Lingayen Gulf. Pampanga and Angat rivers drain the southern part and empty into Manila Bay. North of the confluence of Angat and Pampanga rivers is the Candaba Swamp with an area of 270 square kilometers.
The Luzon Central Plain (Figure 2.1) is composed of middle Tertiary sediments and Quaternary pyroclastics and lava flows, unconformably overlying Cretaceous to Lower Tertiary basement rocks. In the eastern side, the oldest rocks are the Barenas-Baito Formation. In the western side, the basement is composed of ultramafic rocks, gabbros, diabase dike complexes, chert spilites and the Upper Eocene to Oligocene Aksitero Formation. Post-basement stratigraphy on the east is distinct than that on the west. The Mines and Geosciences Bureau (MGB) further classifies the stratified rock at Guiguinto as Quaternary alluvial.
Guiguinto is classified as generally Quarternary Alluvium with the parent material of soils composed of unconsolidated sediments consisting mostly of rock fragments from elder rock formations deposited along valleys and river beds. With deep top soil, the land of Guiguinto is most favorable to agriculture.
Central Luzon Region where the province of Bulacan belongs is one of the highest mineralized regions in the country. Bulacan ranks highest in mineral potential in Region III. It is estimated that Bulacan has a potential reserve of 2.6 billion metric tons of minerals. This estimate is based on the delineated proven, probable and possible mineral reserves of the province. Among the minerals found in the province include iron, clay, construction material, feldspar, guano, rock phosphate, gypsum, cement raw materials, limestone, sand, quartz diorite and granodiorite. However, extractive industries in Bulacan are generally located in the eastern portion of the province. There are no recorded extractive, mining nor quarrying activities in Guiguinto.
Source: Guiguinto Municipal Planning and Development Office