IWRA Proceedings

The land-use planning is the process to regulate and order the future development of cities, and therefore significantly determines how the future demand for drinking water will be spatially located. For this reason, the planning of both land and water use should be done in an integrated manner. The frequent problems of drinking water availability in different urban areas of our country (Chile) make us wonder whether this integration is actually happening.

In this study, we analyze the degree of integration of the main regulatory instruments of the land and water use planning, i.e., (i) the communal regulatory plans that rule the city growth and, (ii) the development plans of the water supply companies, which frame the future investments and therefore the water availability for the coming years. For the analysis, we considered eight representative communes of the Region of Biobio, Chile, and performed quantitative and qualitative analyses to explore the integration of the regulatory instruments. Based on the population densities proposed by the land and water use instruments, numerical indicators were designed and applied to quantify the differences between the potential demand for water and its planned supply capacity. In addition, and based on a set of questions also designed for this particular case, a qualitative analysis was done to identify the level of detail with which each instrument considers the impact on the water use that the other instrument will produce. 

The results of the study show an important lack of consistency between the land-use and the water supply planning instruments regarding the balance between water demand and supply. In some cases, the allowable growth of the city would require the current water supply to increase by thirty times, and to expand its geographic coverage by fifty times. The qualitative analysis shows that the planning instruments of the different communes presented different standards of preparation and therefore levels of integration, suggesting that a methodological guide with minimum requirements to orient the planning process is required. We also recommend that the investment plans of the water supply companies explicitly include the population that the land-use plans project in the urban areas, and that the land-use plans be based on a detailed analysis of the future water availability. Although the use of numerical indicators like the ones suggested in this study is advisable, further research should determine their appropriate levels that guarantee a sustainable development of cities in terms of the water use. These recommendations would certainly require a modification of the current regulatory frame.