Post hydrologic study for the rehabilitation of the Chico irrigation system

• Main Authors: Cruz, Ven Ryan M., Sales, Peter John
• Format: text
• Language: English
• Published: Animo Repository 2001
• Online Access: https://animorepository.dlsu.edu.ph/etd_bachelors/11694
• Institution: De La Salle University

This thesis is a post hydrologic study for the rehabilitation of the Chico River irrigation system. Primarily, this study focused on matching the dependable streamflow with the probable demand throughout the year. It also identified the various losses in the irrigation system. Having no record of flows during its post operation, an assessment of the rates of flow entering the diversion intake was made by routing the inflow hydrograph. The inflow hydrograph was obtained using correlations among flows of this ungauged site with the other gauged areas. The flow duration curve of this ungauged site was made to establish the dependable flow. The dependable flow (supply) can adequately fill in the demand when losses are minimal. The average water conveyance losses was estimated to be 51% of the diverted flow. The losses were found to be contributions from seepage and percolation of water along the perimeter of canals, leakages in the canal holes, and illegal diversions. To lessen the amount of water losses in the diversion requirement, the study recommends concrete lined trapezoidal canals for the main and lateral conveyances of the Chico irrigation system. To carry the dependable flow during the wet season, it is recommended that the main canal be designed with a bed width of 8.30 meters and a depth of 2.60 meters, and that the lateral canals be designed with a depth of 1.10 meters and a bed width of 5.10 meters.