Table of Contents
Data Collection of Parameter Files
Climate Data Collection
Land Cover and Plant Parameters Data Collection
Slope Data Collection
Soil Data Collection
Data Preparation and Processing of Database File
Digital Elevation Model
Land cover and Soil Map Layers
Climate Database File
Landuse/Management Database File
Soil Database File
Slope Database File
Model Simulation Run
Results and Discussion
Water balance simulation
Water Balance Estimation Of Selected Land Cover In Taganibong Watershed, Bukidnon Using GEOWEPP Model
Bryan Allan M. Talisay
The Geospatial Water Erosion Prediction Project (GeoWEPP v10.2) was tested using data from field survey in three study site within Taganibong Watershed, Bukidnon. This field survey data such as waypoints and soil data was processed and edited through ArcGIS software to prepare for model simulation. Weather information were collected using Automatic Weather Station on an hourly basis at the study site. Climate data was created using Breakpoint Climate Data Generator (BPCDG) which allows direct use of observed storm and other daily standard climate datasets. Model simulation was applied in three land cover to evaluate their abilities in reducing runoff and their effects on other water balance parameters. For the study area, the bamboo area with undisturbed harvesting practices has more effective way in reducing surface runoff based on the results of model simulation. On the other hand, the cultivated area (corn) produce highest surface runoff due to the exposure of soil after harvesting period. Statistical analysis was applied to determine the effects of different land cover to the amount of water balance given the amount of rainfall in monthly basis. Magnitude of rainfall as the primary input to water balance has a huge effects in return to hydrologic processes (percolation, soil water, subsurface lateral flow,etc). This study provides a theoretical basis and technical support for land use zoning, policy implementation, soil and water conservation in upland watersheds.
Keywords: GeoWEPP, Water balance, Taganibong, Watershed
A watershed is a topographically delineated area that is drained by a river system (i.e., the total land area above some point on a stream or river that drains past that point). It is a hydrologic unit that often is used as a physical-biological unit and a socio-economic-political unit for the planning and management of natural resources (World Forestry Congress, 2003 as cited by Talisay, 2015). As a component of forestry, watershed provides quality and quantity freshwater for unlimited human needs and for the habitat of wild animals. Most of the country’s watershed has undergone massive changes over the years and are currently in varied stages of considered degradation thereby needing deliberate rehabilitation efforts. Out of these watershed areas, some are 127 proclaimed watersheds, which are intended to be managed and protected. However, these areas were heavily encroached and subjected to various types of cultivation. Consequently, 90% of these proclaimed watersheds were categorized as hydrologically critical, characterized by degraded biophysical conditions and have become risks to downstream infrastructure (DENR-ERDB, 2010). As evidences of watershed degradation are the physical manifestations of problems such as soil erosion, polluted water runoff, evidence of frequent flooding, sediment-filled channels and reservoirs, and shortages of potable water.
Soil erosion and surface runoff in watersheds have a significant effect on humankind. Thus, it generates serious environmental and economic problems. It is associated with adverse environmental impacts and crop productivity loss (Lal, 1995; Pimentel et al., 1995) that makes its understanding important in assessing food security (Daily et al., 1998) and environmental safety (Matson et al., 1997). It is one of the most serious environmental problems in many areas including upland watersheds in the Philippines.
There have been several models developed to estimate sediment yield, runoff and soil erosion, but in this study, the Water Erosion Prediction Project (WEPP) is being applied. It was developed to estimate soil erosion, water balance and runoff based on specific erosion factors including soil type, climate conditions, ground cover percentage, and topographic condition (Flanagan and Livingston, 1995). The WEPP model calculates sediment yield, runoff, infiltration, and erosion and deposition rates for every day and for multiple time periods (i.e. Monthly or yearly). Since WEPP is process-based model, it requires a great amount of input data to evaluate erosion and sediment yield potentials (Flanagan and Nearing, 1995).
GeoWEPP, a geospatial erosion prediction model, was established to integrate the advanced features of GIS (Geographical Information System) within, such as processing digital data sources and generating digital outputs (Renschler, 2002). In this study, GeoWEPP (v10.2) were used to estimate and predict the water balance of specific study area in Taganibong Watershed.
The research study was conducted within the three identified land cover in Taganibong Watershed (bamboo, cultivated and fallow), which lies between 124 degrees 57 minutes to 125 degrees 35 minutes east longitude and 7 degrees 48 minutes to 7 degrees 57 minutes north latitudes situated within the Municipality of Maramag and City of Valencia. It covers the Barangays of Guinuroyan, Tugaya, Barobo, Mount Nebo and Lumbo, which is part of Valencia City; Barangay Kisanday and Dologon of the Municipality of Maramag. It has an elevation of 392 meters above sea level (masl). This area has a tropical, maritime climatic condition and belongs to third type having no very pronounced season. Dry season is experienced from November to April while the rest of the year is wet.
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Figure 1. Location Map of the Study Area
 Research Associate, Phil-LiDAR 1 Project, College of Forestry and Environmental Science, Central Mindanao University, Musuan, Bukidnon, Philippines.
- Quote paper
- Forester Bryan Allan Talisay (Author), 2015, Water Balance Estimation Of Selected Land Cover In Taganibong Watershed, Bukidnon Using GEOWEPP Model, Munich, GRIN Verlag, https://www.grin.com/document/342254