This case study by Clara Roa of the Centro Internacional de Agricultura Tropical (CIAT) looks into the relation between water availability and water consumption for multiple uses in a Colombian micro-catchment.
Within the framework of the project "Youth in Research" coordinated by the Communities and Watersheds program at the International Center for Tropical Agriculture - CIAT, and funded by the Kellogg Foundation, the youth from the Los Sainos watershed (447 Ha) prioritized water availability in relation to water quality and land use, because of the scarcity periods suffered by the watershed community in recent years. This work consisted of a participatory research with youth of the watershed to answer the following question:
Where are the hot spots in the micro-watershed that through better management practices could contribute to reduce the risks of the community to experience water shortages and deterioration of water quality for all uses in the watershed?
To answer this question we addressed the following:
- What are the water needs of a rural family for domestic and productive uses?
- What is the water supply in the watershed and does it satisfy the needs for the zone?
- What is the relation between land use and water quality?
To quantify consumption and water use, simple equipment was used such as chronometers, recipients, and burettes; and for quality measurements, the equipment used was Hach© for pH, dissolved oxygen, turbidity, conductivity, total dissolved solids, calcium hardness and total hardness and the Oxfam© del Agua equipment for fecal and total coliformes.
The sampling and measuring period was a whole dry season (June to August 2005). It was found that water availability satisfies the current water needs, although with a reduction of water availability of between 15% and 20% the community would start to experience scarcity. Because the system of water supply does not have any treatment for coliformes, they are present even in protected areas, and all individual households need to treat the water for domestic consumption. A close relationship between land use and water quality is demonstrated. The negative impacts on water quality were clearly determined in the downs stream from the discharges of pig manure without treatment and downstream discharges from septic tanks with poor or no maintenance. The quality parameters with greater variability and land use dependent are conductivity, total dissolved solids, fecal and total coliformes, nitrates and phosphates. Other parameters such as temperature, pH, dissolved oxygen, turbidity, calcium hardness and total hardness depend more on topography and land erosion.
Great difference in water technologies are seen between the upper, middle and low sections of the watershed. The majority of the houses in the upper catchment have biodigestors, use less water in cleaning pig houses, and use sand filters; these technologies are in some cases, unknown to the people in the middle and low areas. It was showed during this study that these technologies were efficient because they reduce water pollution to the streams, improve water quality water for human consumption and allow a more efficient water use. Among the strategies for a more efficient water use, the community identified the implementation of these technologies in the whole watershed, achieving the support from the governmental institutions to improve and maintain these technologies, and the willingness of landowners to protect the streams and riparian areas.