A Central Luzon, Philippines Gamboa, Renato Simon creator Gupta, Ashim Das Chairperson Tawatchai Tingsanchali Examination Committee Christoph, Ing. Fried Examination Committee US-ASEAN Development Cooperation Programme Scholarship Donor text th Bangkok Asian Institute of Technology 1982 monographic eng

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ix, 121 p. The study was aimed at developing a computer model that will simulate the movement of groundwater at the Agno Groundwater Basin, Central Luzon, Philippines. The basin which is about 50 km by 54 km was modeled using a variable grid system. The finite difference equation developed for the model was solved by the modified interactive alternating direction implicit method using the Thomas Algorithm. The computer equivalent of the model was written in FORTRAN language and run in the IBM System/3031. Two grid systems were tried: 50 x 50 grid (800m x 2000m grid size) and 90 x 90 grid (400 m x 1000 m grid size) using two time increments: 30 days and 90 days. After testing for computer storage and time usage, and consistencies of computed results, the 50 x 50 grid system and 90 days time increment was used in the later part of the study. The aquifer type treated were two types: unconfined and confined. Further, the constant boundary treatments were al so two types. The first type is constant head throughout the simulation period, that is, the head is held at a constant value for the whole of the simulation period. The other is constant head at a time increment, that is, the head is held constant although out the iterations of a time step calculations. Calibration was done in two steps: blanket and selected adjustments of model parameters. For the comparison of computed results, available records on piezometric head observations and maps on piezometric head distribution were utilized. The model calibration resulted to a close duplication of the recorded responses on a general basis. The flow domain of the model was divided into four well field areas and each of which is considered as upstream or downstream well field according to its relative position in the general direction of the ground water flow. Using these arbitrary divisions of the modeled area, three different areal distribution of pumpings were developed for purposes of simulation. The three pumping schemes are: Scheme I - Uniform Pumping (all the wells in the well fields start pumping at the same time) , Scheme II - Upstream Start of Pumping (wells at the upstream well field start pumping first followed by the other well fields in the downstream direction) , and Scheme III - Downstream Start of Pumping (wells at the downstream well field start pumping first followed by the other well fields in the upstream direction) . Using the information on the crops to be planted, its water requirements and the cropping calendar for the modeled area, the groundwater withdrawals for each pumping scheme were determined and utilized to predict the responses of the aquifer. A thesis submitted in partial fulfillment of the requirement for the degree of Master of Engineering, School of Engineering and Technology Thesis (M.Eng.) - Asian Institute of Technology, 1982 Water, Underground Simulation methods Water, Underground Philippines Agno River Basin Asian Institute of Technology. http://203.159.5.9/ait-thesis/detail.php?q=B21420 http://203.159.5.9/ait-thesis/detail.php?q=B21420 180598 20260818132652.0