Impact of spatial land use change on green space and water yield in Batu Pahat, Johor

Globally, the accelerating urbanization led by the industrialization and population growth can cause the environment degradation. The urban expansion particularly to the conversion of land activities affects the ecosystem services critically. Water yield acts as one of the important elements in the water cycle has significant impacts towards the water resources management particularly to the flood mitigation. This study helps to fill in gap of determining water yield in the urban area to reduce water stress due to the spatial land use change. The research objectives are to i) quantify the spatial land use change in Batu Pahat, Johor in year 1999, 2010 and 2018, ii) to identify the water yield of Batu Pahat in years 1999, 2010 and 2018, and iii) to determine the relationship between water yield, vegetation and urban expansion. The methods used are landscape ecological analytics, water yield simulation and statistical analysis by using the software included ENVI, AreGIS, FRAGSTATS, Annual Water Yield InVEST Model and Microsoft Excel. Raw satellite images were extracted for the year 1999, 2010 and 2018. The supervised classification of land use land cover (LULC) was conducted based on the land use type which are built-up area, cleared land, vegetation and water bodies. This study generates results for the percentage area of change for each LULC class. The highest percentage of area in Batu Pahat is vegetation while the cleared land ranked the lowest. The results for water yield from the InVEST model shows that the vegetation has the higher water yield than built-up. Six metrics included patch density (PD), largest patch index (LPI), landscape shape index (LS1) and mean patch area (AREA_MN) were used to quantify the landscape pattern of land use at the landscape level. The results found that the green space experience an aggregation and fragmentation loss of patches. Therefore, it is very important to sustain the vegetation are in order to provide the water yield for the area. In conclusion, this study will aid in the understanding and provided empirical data result for managing urban expansion and sustaining the water yield in Batu Pahat, Johor by using the integrated approach of Geographical Information System (GIS), remote sensing and landscape ecology to produce land use and water yield map as final output.