Basic Morphology and Morphometry of Lake Danao in Ormoc City, Leyte, the Philippines
John O. de la Cruz1*, Jeremy B. Romero2, Allan Fritz Gerald N. Amistoso2, Victor M. Romero II2, Mark T. Lama2, Rhea Mae S. Dañal2, Maria Elisa B. Gerona-Daga2, and Racquel U. Tabornal3
1Leyte Samar Heritage Center, University of the Philippines Tacloban College,
Tacloban City 6500 the Philippines
2Division of Natural Sciences and Mathematics,
University of the Philippines Tacloban College, Tacloban City 6500 the Philippines
3Mathematics and Statistics Program, University of the Philippines Cebu,
Cebu City 6000 the Philippines
*Corresponding author: jodelacruz@up.edu.ph
ABSTRACT
Information on the morphology and morphometrics of Lake Danao – an integral part of the Lake Danao Natural Park in Ormoc City, Leyte, the Philippines – is incomplete and obsolete, which necessitates validation and updating. To address this gap, GIS, ground truthing, and bathymetric surveys using modern methods and technology alongside classical computing approaches were conducted in July 2022 to verify the accuracy and provide supplementary information to the lake’s existing basic morphometrics compiled from various sources. The results revealed a maximum length of 2,962 m, a maximum width of 825 m, and a shoreline length of 8.23 km. The relative depth (6.43%) and basin permanence index (6.83) demonstrated the lake’s extensive depth (maximum = 85.8 m). Using the frustum volume formula, Lake Danao is estimated to hold a maximum of ~ 56,214,143.56 m3 of water. The calculated surface area is 1,398,300 m2, 5.4% smaller than the previously published area of 1,480,000 m2 by NAMRIA in 1956. Additional studies are needed to confirm if this discrepancy is due to limitations in previous mapping techniques or indicative of actual area shrinkage. Local authorities can use these findings to update Lake Danao’s basic morphology and morphometrics information and conduct further research. However, cautious application of the results is necessary when drafting conservation and management strategies for the sustainable development of the protected area. . . . . . continue reading