Evaluating the effectiveness of policies and regulations to protect water resources from peri-urban expansion in Chile, Brazil, and Australia

Every country faces unique challenges to protect the quantity and quality of its water resources, whereas the legal instruments warranting such protection vary in their degree of success in accomplishing their goal. This work evaluates the dynamics of peri-urban expansion (UE) through multitemporal satellite images and the environmental regulatory tools in three protected areas (PAs) used as water reservoirs located in three countries in the southern hemisphere (Chile, Brazil, and Australia). Landsat images from 1985 to 2020 were buffered and mapped using supervised classification at 10-year intervals. We quantified the increase or reduction of the vegetation, shrubs, planted forest, agriculture, pasture, bare soil; expansion of consolidated urban area, and water bodies. When it comes to policies and regulations, regardless of the socio-environmental and economic conditions of each country, there are converging political and economic interests in the regulations to promote peri-UE in clear contradiction with the protection of water resources. Effective management of PAs is impaired and hindered due to variation in how intensely existing policies and regulations are executed, or omitted due to the lack of financial resources, monitoring, and chronic failure of integration between urban master plans, buffer zones, and political decisions.