The political boundaries of Mabini expanded to fourteen barangays in later years. The vastness of its agricultural areas and the fertility of its soil were the main factors that attracted the early settlers in the area. These settlers came from the neighbouring towns of Guindulman, Duero and Jagna and the neighbour province of Cebu. The farm cultivation of those early settlers catalysed the rapid agricultural growth in Mabini. Incidentally also, during the American occupation, no major damage was recorded in the area except for one sailboat which was sunk by an American sea patrol boat while loading tan bark. There were also no major damages recorded during the Japanese occupation except for the brutal execution of Dionisio Bernales and Restituto Paguia by the Japanese soldiers. It was probably because there was no Japanese garrison established in the town during the period.
Geographical Location and Accessibility. The municipality Mabini is located in the northeastern part of the island-province of Bohol. It is approximately 104 kilometres from the capital city of Tagbilaran. Technically, Mabini’s town center is located at geographic point of 9.510 46’ 56’’ North latitude and 124.320 11’ 26’’ East longitude. The municipality is bounded on the east by the Mindanao Sea; on the north by the municipality of Ubay; on the south by the municipality of Candijay; and by the municipality of Alicia on the west. Mabini is accessed by an all-weather coastal road.
Land Area. The municipality covers 10,457.48 hectares or 2.54% of Bohol’s total land area. Some portions of Mabini are contested areas. A portion of Sitio Tawog, Barangay Tangkigan is contested with the municipality of Candijay while portions of Barangays Bulawan, Cabidian and Abaca are contested with the municipality of Alicia. In terms of political jurisdiction, Mabini consists of 22 barangays – 16 coastal and 6 inland barangays. Mabini’s territory also includes a portion of Cogtong Bay and Lumislis island which it shares with the municipality of Candijay.
Seventy-four percent (74%) of Mabini’s land area is classified as alienable and disposable (A&D) lands or privately-owned lands while 26% is classified as forestlands. Mabini spans portion of 4 watersheds, namely: Carood, Cabidian, Biabas-Ondol and Kabulao (ESSC,2003). The area coverages of Cabidian, Biabas-Ondol and Kabulao watersheds are almost entirely within the municipality. Cabidian watershed which measures 1,581 hectares in total land area drains into the Cogtong Bay. Kabulao and Biabas-Ondol watersheds drain into Kabulao Bay. A small portion of the municipality’s area on the other hand is within Carood watershed. This portion is specifically located in the upstream areas of Barangays Cabidian and Abaca. The central portion of Mabini has no distinguishable surface water drainage network. This indicates that surface water runoff infiltrates into the ground and drains into the sea through an aquifer drainage.
Topography and Slope. Seventy-five percent (75%) of Mabini’s total land area is characterized as having level to rolling terrain or slope range of 0-18%; areas with rolling to mountainous terrain (slope range of 18-30%) at 14%; and areas with steep terrain (50 and above slope) at 11%. The highest elevation in the municipality, at 428 masl is located at the boundary between Ubay and Mabini.
A water study commissioned by the provincial government in 1998 for the province of Bohol estimated the province’s average annual rainfall at 1,886 mm/year. A study done by the Environmental Science for Social Change (ESSC) in 2003 for Carood watershed, which includes a small portion of Mabini, stated that the averages annual rainfall of the watershed is 2,318.1 mm/year.
Soil Slopes. The soils of Mabini are generally 4 types: clay, rough stony land and sandy loam (existing in the uplands and lowlands) and hydrosols or swamp and marsh soils. These general types are distributed in 6 soil regions which include Faraon clay, Ubay clay, Candijay clay, rough stony land, Ubay sandy loam and Hydrosol. Faraon clay constituents roughly 69% of the municipality’s area followed by Ubay sandy loam at a little over 12%.
Faraon clay in particular is characterized brown dark brown, to almost black heavy surface soils underlain by highly weathered limestone resting on partly consolidated limestone rock. In cultivated areas, the soil ranges in depth from 10 to 15 centimeters. The general topography is hilly to steep with a “parang” type of vegetation. In some hills, molave and second growth forest are found. In the cultivated portions, uplands, rice, cassava, corn, camote, gabi, ubi and coconuts are grown.
Geology. The geologic formations in the municipality consist of Ubay volcanics which covers the largest extend at 29% of Mabini’s total land area, Quaternary Alluvium (23%), Ubay volcanics (29%), Sierra Bullones Limestone (16%), Carmen Formation (26.6%), Bohol Serpentinite (4%) and Amphibolites (1.4%).
The same study also identified some barangays as susceptible to seasonal flooding with a depth of less than 1 meter to greater than 1 meter.
General Land Use and Vegetative Cover. Lands utilized for agricultural purposes comprise 71% of the total land area of Mabini while upland forests and mangroves comprise 26.5%. The rest comprised built-up areas, roads, small-scale mining, etc.
Easily distinguished vegetative cover consists of patches of forests located in the upstream areas of the Poblacion and in Barangays Marcelo and Tambo; and mangroves along the municipality’s coastline. Grassland also cover a substantial portion of the municipality of which are generally used as grazing areas of cattle and other livestock.