Systems approach to comprehensive land use planning integrating disaster risk reduction and climate change adaptation in San Jose City, Philippines

A model-based systems approach in optimizing land use spatial allocation integrating disaster risk reduction and climate change adaptation was developed in the study and operationalized in San Jose City, Philippines. Land use planning and analysis system (LUPAS) framework, developed by Roetter, et al. in 1998, was adopted and modified in the study. Land area of the city was divided into 73 land management units, subdivided into 1-ha 17203 grids. Eight objective functions emerged from alignment of development goals from national to household level: (1) maximize tomato production; (2) maximize ampalaya production; (3) maximize rice production; (4) maximize onion production; (5) maximize farmers' income; (6) maximize agricultural employment; (7) minimize disaster risk; and (8) maximize residential suitability. Current condition and 2035 scenarios were constructed. Climatic scenarios were reflected in crop suitability rating by conducting land evaluation; extreme events scenarios were manifested in hazard index scores. Disaster risk assessment was conducted. Gurobi, a multiple goal linear programming (MGLP) software, was employed. Results showed that under current condition, the city can meet its crop production (tomato-268293 mt/yr; onion-10018 mt/yr), increase total farmers' net income to Php 7B, allocate agricultural labor to 354,862 persons, minimize disaster risk of the city to 0.53 and allocate suitable residential area of 567.87 ha, by optimally allocating those grids to suitable use. Under 2035 scenario, the city can still meet its target crop production (tomato-242177 mt/yr; ampalaya-192 mt/yr; rice-89572 mt/yr; onion-10164 mt/yr), increase total farmers' net income to Php 6B, allocate agricultural labor to 341,547 persons, minimize disaster risk to 1.45 and allocate suitable residential areas of 970.05 ha to additional populace, despite change in crop suitability, increase in hazard susceptibility and increase in population. Systems approach is in optimal land use allocation, guided by LGU's development goals, constrained with available resources and subjected to climate change and disaster risk.