Managing waste in a watershed: The case of the Paradeke Oya watershed

Abstract

In 2007, areas within the Paradeke Oya watershed were impacted by an outbreak of Hepatitis A caused by the poor health and sanitation conditions in the watershed. In order to examine the underlying causes of the spread of this disease, the National Water Supply and Drainage Board contracted the Neo Synthesis Research Centre to initiate a comprehensive study.

Part of this study involved an assessment of the riparian zone of the Paradeke Oya since riparian zones are potentially valuable indicators of watershed condition. The study used the methodology espoused by a modified version of the Tropical Rapid Appraisal of Riparian Condition (TRARC) that is a visual assessment of the riparian zone using simple indicators of condition. The main areas of assessment were carried out on Plant cover, Erosion, Flow regime and Pressure; the last area of assessment includes the entry of feacal matter, solid waste, Chemical Fertilizer, Chemical Pesticides. It also included the occurrence of illegal construction, the proximity of toilets, damage from man made fire, animal grazing and other phenomena like bathing, washing clothes etc.

The data generated revealed that the waste generated from the Paradeke Oya watershed took many forms. Sewage, grey water and solid waste were a problem in both the urban and rural sectors. However the most significant source of contamination came from the use of chemical fertilizers and pesticides.

The degradation of the natural forest and riparian ecosystems combined with the lack of sanitation both in the estate and urban areas has had a debilitating impact on stream water quality. The absence of controls for the use of agrochemicals in environmentally sensitive areas is a major problem.

The most effective way to reduce the pollution load is to decrease pollution at the origin. Hence, corrective actions need to include the introduction of effective solid waste management through separation and recycling. The management of sewage through the biogas toilets for the estate line communities offers a viable option that requires changes in community practices. Centralized sewage collection and the construction of an anaerobic digester by the National Water Supply and Drainage Board could afford the opportunity for energy generation for Pussellawa town. The options are many; but what is critical is the adoption of a watershed management perspective in the planning and implementation of the restoration process. The monitoring of such programmes must use economic, social and ecological indicators of success.