Systems approach to mainstreaming disaster risk reduction in the comprehensive land use plan of San Jose City, Philippines

A model-based systems approach in optimizing land use spatial allocation integrating disaster risk reduction was developed in the study and operationalized in San Jose City, Nueva Ecija, Philippines. Land use planning and analysis system (LUPAS) framework, developed by Roetter, et al. in 1998, was adopted and modified in the study to mainstream DRR. Land area of the city was divided into 73 land management units, subdivided into 1-ha 17203 grids. Five land use types. specifically, tomato, bitter gourd, rice, onion and residential areas were allocated using multiple goal linear programming (MGLP). Gurobi was the software employed. Minimizing disaster risk of the city, as one of objectives identified, is a function of hazard, vulnerability and allocation of residential areas. Disaster risk assessment was conducted by rating each grid with its corresponding vulnerability and hazard susceptibility scores. Mean scores of exposure, (2.74), susceptibility (3.69), and lack of adaptive capacity (2.52), generated a mean vulnerability index score of 11.02, relatively low compared to the highest possible score of 25. Future 2035 scenarios were constructed to simulate extreme events on flooding, agricultural drought, rain-induced landslide and earthquake. Keeping vulnerability scores constant, hazard susceptibility scores would increase from 1.18 under current condition to 1.42 under 2035 scenario; consequently, disaster risk index would increase from 12.98 to 15.6. Areas along river network received higher hazard score, attributed to the higher weight placed on flooding. Land allocated to the five land use types, under current and 2035 scenarios, can meet target crop productions while increasing farmers' net income. Further, the allocation can minimize disaster risk of the city to 0.53 and 1.45, while providing safe residential areas of 567.87 ha and 970.05 ha to additional populace, under current condition and 2035 scenario. Systems approach is indeed vital in optimizing land use allocation, guided by LGU's development goals, constrained with available resources and subjected to disaster risk.