Baguio City Ecological Profile 2018 Chapter II GEO- PHYSICAL ENVIRONMENT LOCATION AND AREA Baguio City is geographically located in the south central part of Benguet Province in the Cordillera Administrative Region (CAR). The developed portion of the city corresponds to a plateau that rises to an elevation of 1,400 meters. Total land area is 57.49 square kilometers enclosed in a perimeter of 30.6 kilometers. Approximately, the city is 250 kilometers north of Manila. POLITICAL BOUNDARIES Map 1: Location Map of Baguio City Page 5 Baguio City Ecological Profile 2018 TOPOGRAPHY Elevation ranges from 900 meters along the Bued River to 1,600 meters at Pacdal. Majority of the slopes (about 78% of total area) are gentle to moderately steep with slope of less than 30%. Only about 22% of city’s land area has steep slopes greater than 30% Table 1 : Slope Categories, Baguio City SLOPE AREA DESCRIPTION GRADE (HAS.) PERCENT Level to gently sloping 0- 8% 1,530.78 26.63 Gently sloping to undulating 9- 18% 955.58 16.62 Undulating to moderately steep 19- 30% 2,011.50 34.99 Moderately steep to steep 31- 50% 785.18 13.65 Very Steep >50% 465.96 8.11 Total 5,749.00 100.00 Page 6 Baguio City Ecological Profile 2018 Map 2: Slope Map GEOLOGY ZIGZAG FORMATION This is a sequence of Late Oligocene to Early Miocene conglomerates, sandstones and shales, in places with limestone lenses uncomformably resting on top of the Pugo Formation. A portion of this sedimentary sequence is intruded by quartz diorite porphyry, producing mineralized skarns and marbles. The Halfway Creek Formation (UNDP, 1987) and Camp Three Beds (Mitchell & Leach, 1991) were regarded as part of Zigzag Formation. Among the formations in the area, this unit is considered to have the highest potential for groundwater. KENNON FORMATION This Middle Miocene formation unconformably overlies the Zigzag formation and rests below the Klondyke Formation. It consists principally of massive to buff gray biohermal limestone with associated calcarenites and calcirudites. The basal portion consists of wackes, including a conglomeratic calcarenite which contains clasts of volcanic rocks, diorite pebbles and cobbles. Lenses of sandstones and siltstones up to 0.3 m thick have been observed in the middle section. Mirador Limestone is considered here as part of Kennon Formation (S. David). For groundwater resources, the Kennon Formation is deemed to have more moderate potential. Page 7 Baguio City Ecological Profile 2018 KLONDYKE FORMATION This is a thick sequence of Middle Miocene to early late Miocene clastic sedimentary rocks consisting mainly of polymictic conglomerates with interbedded sandstones, siltstones, shales and in places intercalated with flow breccias and pyroclastic rocks. It rests unconformably over the Kennon Limestone and underlies wide areas of the western sides of Baguio City Quadrangle and exposed at higher elevation. Different authors give different thickness. Balce et al (1980) gave an estimate of 1,798 meters for the Kennon Road section but admit it might be higher in other places. Durkee and Pederson (1961) estimated the thickness in this section to be 2,820 m. De Leon, et al (1990) gave an estimate of 3,500 m. for Marcos Highway section of the formation. Valley areas overlying this formation may yield small quantities of groundwater but most parts have poor groundwater potential (Quema, 1971). Monzon (1991) meanwhile, reported the presence of saturated zone in the conglomerates, limestone and sandstone in the area. Based on these observations, this study considered the Klondyke formation as having moderate potential for the groundwater availability. BLACK MOUNTAIN QUARTZ DIORITE PORPHYRY This is typified by the quartz diorite porphyry which hosted copper deposits and other mineralization in the district. It is differentiated from the CCD by its porphyric texture and younger age (Late Miocene). Like the CCD however, this rock unit has low potential for groundwater availability. SOILS There are three (3) main types of soil : Bakakeng Sandy Clay Loam, Mirador Clay Loam, and Tacdian Loam. Almost half of the study area is covered by the Bakakeng Sandy Loam, which incidentally is the second largest soil group in southern Benguet. It cuts across the area from the north to southeast and extends eastward to Itogon. Mirador Clay Loam is found in the southwestern part of the study area. The smallest soil group, Tacdian Loam, lies in the mid-north of the area. The physical characteristic of these soils types; their structure, consistency, and texture per horizon can be seen in the table below. Of the three- (3) soil types, Tacdian has the thinnest surface soil, being 5 to 10 centimeters from the surface. Cultivation of this type of soil along steep slopes may, without adequate control of surface run-off, result to its erosion down slope. Bakakeng Sandy Clay Loam and Mirador Clay Loam have thicker topsoil. If however, they are cultivated along steep slopes, and no adequate measures are undertaken to control slope erosion, the topsoil will gradually be washed away by running water. This eventually exposes the subsoil, which is unproductive for plant growth. The external drainage of these soils is of the utmost importance. The terrain where these soils are located can be best described as moderately steep to very steep. Without adequate measures to regulate drainage’s, these soils will be excessively drained, thus resulting to massive erosion. In general, soils within the city are classified as clay loam. Soil materials for embankment or fill purposes can be found in almost any place in the area. Most of the hillsides can be tapped to yield unlimited materials for construction purposes. Page 8 Baguio City Ecological Profile 2018 RIVER SYSTEM The city is criss crossed by several rivers among which are the Bued, Balili, Galiano– Camp-Asin, Naguilian Rivers and Ambalanga. The widest river is the Bued River followed by the Balili River. DRAINAGE SYSTEM Surface water drains through the rivers; 1) to the east is the Ambalanga which follows a southeasterly to easterly course and drains into the Agno River, 2) to the north is Balili River, which follows a general northerly course and converges with the Bauang River basin to the north-northwest, 3) to the west is the Galiano River which drains into the Aringay River; and 4) to the south is the Bued River which drains into the Patalan River and the Lingayen Gulf. Drainage facility at the Central Business District is through an underground drainage system along Magsaysay Avenue constructed by the Department of Public Works and Highways and drains towards the Balili River. LAND RESOURCES EXISTING LAND USE AND LAND USE TRENDS Residential area (56.35 percent) occupies the largest land use and is therefore the most dominant among all the urban uses. Commercial areas occupy some 317.13 hectares or approximately 5.52 percent of the City’s total land area. These are found mostly at the Central Business District and along major thorough fares in the City like Magsaysay Avenue, Bokawkan Road, Naguilian Road, Marcos Highway and Kennon Road. Various private and public institutions operating in the City take up some 233.57 hectares (4.07 percent). These institutions include schools, hospitals, churches, military reservations, and government facilities. Among the military reservations are the A.Philippine Military Academy, Navy Base and Camp Allen. Planned Unit Development Zone takes up a small portion of the City’s land at only 57.89 hectares or 1.01 percent. The Philippine Export Zone Authority in Loakan is the largest industrial estate in the Baguio and is home to multi-national companies like Texas Instruments,B. Moog Controls Corporation. Table 2 : Existing Land Use Categories Existing Land Land Use Percent Area (Hectares) R1 - Low Density Residential Zone 1,395.21 24.27 R2 - Medium Density Residential Zone 610.26 10.61 R3 - High Density Residential Zone 1,234.44 21.47 C1 - Low Density Commercial Zone 147.62 2.57 C2 - Medium Density Commercial Zone 96.62 1.68 C3 - High Density Commercial Zone 72.89 1.27 Page 9 Baguio City Ecological Profile 2018 Existing Land Land Use Percent Area (Hectares) Camp John Hay-Planned Unit Development Zone (Special Tourism Economic Zone) 301.86 5.25 Camp John Hay-Watershed / Protected Forest Zone (Reservation) 323.55 5.63 Planned Unit Development Zone 57.89 1.01 General Institutional Zone 233.57 4.07 Parks and Recreation Zone 60.80 1.05 Watershed/Protected Forest Zone 240.37 4.18 Vacant Forested Areas 591.84 10.29 Slaughterhouse Zone 2.70 0.05 Cemeteries/Memorial Parks Zone 13.88 0.24 Airport Zone 32.16 0.56 Utilities Zone 9.85 0.17 Special Use (Bureau of Plant Industry) 8.98 0.16 Special Use (Bureau of Animal Industry) 104.35 1.81 Roads/Roads right-of-way 210.16 3.66 Total 5,749.00 100.00 Though already dwindling, pockets of pine forested areas remain visible in the City’s landscape. The remaining forested area accounts for about 4.18 percent of the total land area. Pine forests are found mostly at the outskirts of the City, close to the City boundary. Table 3 : List of Watershed/ Protected Forest Zone AREAS IN PARTICULARS HECTARE (HA) 1. Busol Forest Reserve (Baguio Side) 112.00 2. Buyog Forest Reserve 21.93 3. Camp 8 27.50 4. Crystal Cave 4.07 5. Forbes Park 1 29.85 6. Forbes Park 2 16.86 7. Forbes Park 3 21.23 8. Lucnab 5.98 9. Pucsusan 0.95 TOTAL 240.37 Source: DENR-Forest Management Services. Page 10 Baguio City Ecological Profile 2018 Map 3: Existing Land Use Page 11 Baguio City Ecological Profile 2018 CLIMATE Baguio City is known for its cool climate.