Status : Verified
| Personal Name | Arellaga, John Lester A. |
|---|---|
| Resource Title | Assessment of the Impact of Agricultural Land Cover Changes in Aklan River Watershed, Philippines |
| Date Issued | 16 June 2025 |
| Abstract | This study utilized the Soil and Water Assessment Tool+ (SWAT+) to evaluate the impact of changes in agricultural land cover on streamflow and sediment output. The watershed has seen substantial changes in land use, most notably the conversion of open forest into agricultural land. In 2010, 2015, and 2020, land cover data indicated a 59.05% decrease in open forest areas over the decade, while annual and perennial agricultural areas experienced significant increases. Daily streamflow data from 2007 to 2018 were used to calibrate and validate SWAT+, and the model performed well (R² ranged from 0.75 to 0.83; NSE ranged from 0.76 to 0.78; PBIAS ranged from 24.63 to 18.89; RSR ranged from 0.64 to 0.51). Simulations of sediment yield showed an increasing tendency, increasing by 63% from 20.564 t/ha/yr in 2010 to 33.524 t/ha/yr in 2020. A study of Landscape Units (LSUs) revealed localized increases in sediment yield. For example, LSU 2210 saw a rise from 12.2 t/ha/year to 17.7 t/ha/year, and LSU 2160 saw an increase from 5.28 to 8.96 t/ha/year within the same period. Significantly, in several LSUs, scenarios that simulated the conversion of forests to perennial crops yielded larger sediment outputs than those that simulated the conversion to annual crops. This was because the land location in these scenarios was on steeper slopes. As the Department of Agriculture–Western Visayas indicated that Aklan was the leading producer of cassava, eggplant, and irrigated palay, with corresponding growth rates of 15.71%, 13.21%, and 7.13%, the selection of BMPs was in line with regional agricultural priorities. The study demonstrated the effectiveness of Best Management Practices (BMPs) in reducing sediment yield. In particular, mulch tillage of eggplant (BMP 2) decreased sediment yield by 33.106 t/ha/year, whereas conservative tillage of cassava (BMP 1) decreased by 32.172 t/ha/year. Dense grass waterways (BMP 4) accomplished the most notable reduction, lowering sediment yield do |
| Degree Course | Master of Science in Environmental Engineering |
| Language | English |
| Keyword | Aklan River Watershed, Sediment Yield, Agricultural Land Cover Changes, SWAT+ |
| Material Type | Thesis/Dissertation |
Preliminary Pages
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Category : F - Regular work, i.e., it has no patentable invention or creation, the author does not wish for personal publication, there is no confidential information.
Access Permission : Open Access