IWRA Proceedings

Environmental indicators and indexes are essential tools for tracking environmental progress, supporting policy evaluation and informing the stakeholders. Decision makers need the appropriate indicators and indices to assess, track, and equitably weigh integrated human health, socio-economic, environmental, and ecological factors to foster sustainability in watershed and micro- watershed. The Andean region holds 9.5% of the world’s fresh water reserves and plays the pivotal role of providing water for the majority of South American watersheds. However, unsustainable practices such as overgrazing in the water recharging zones, deforestation, mining, deficiencies in practices agriculture, changes on the use land and climate changes, directly impact their surrounding environment and water resource. The purpose of this paper was to conceptualize and to present a water quality index (WQI) for Andean micro-watershed.

The methodology used for build index, was a combination of pressure-state-response (PSR) indicators, logic fuzzy and management knowledge. The PSR model is based on the concept of causality: human activities exert pressures on the environment (pressure) and change its quality and quantity of natural resources (state). Society responds to these changes through environmental, general politics, economics and sectorial responses (response). Fuzzy logic is an artificial intelligence (AI) technique that tries to emulate human decision processes. Fuzzy sets can have a variety of shapes. However, for simplicity in the computation process and adequate representation of the expert knowledge, trapezoidal and triangular functions were defined in this study. Knowledge management describes the strategies and processes of acquiring, converting, applying, protecting and transferring knowledge to improve decisions. The index WQI was applied at the El Chocho micro-watershed in Colombia. This microcachment has suffered a huge environmental damage, as a consequence of the change in the use of the land, the increase of the population, the discharge of untreated domestic wastewater, the poor management of the solid wastes, and the discharge of the acid coal water. These circumstances generate different kind of conflicts, especially the access to the water, degrading uses of water and activities which affects directly or indirectly the quantity and quality of water. 

As results of this research project were obtained the follows indicators and index. Three indicators of pressure were defined: wastewater untreated, mining and erosion. Three indicators of state were defined: biochemical oxygen demand and fecal coliform. Three indicators of response were defined: treating wastewater, best practices in mining and reforestation and re-vegetation policies. To each indicator was defined a function of fuzzy logic. Through the combination of these indicators was defined the water quality index (WQI). To operate index were defined 207 decision rules. These results indicate high degradation level in water resource in this microwatershed. The index value was high in each zone: low, medium and high. These results indicate high degradation level in water resource in this micro-watershed. This study indicates the possibility of building and applying an index of water quality to support management decision process in Andean microwatersheds. More applications are necessary to evaluate this index.