FOREST CONVERSION AND WATERSHED MANAGEMENT

Abstract

The watershed is a major management unit that includes land, forest and water resources. These resources are vital to the developing countries due to their large and rapid-growing populations. The high population pressure results in the cultivation and exploitation of marginal lands that are ecologically fragile. The upper watersheds with steep slopes are very easily degraded by human-related activities due to their delicate ecological balance. It is evident that watershed management is crucial to the survival of the developing countries where natural resources are degrading at an alarming rate due to unsustainable development and poor watershed practices. There must be a basic understanding of the various hydrological processess and natural cycles in the tropical rain forests to devise appropriate watershed programmes. Hydrological processes such as evapotranspiration, interception, stemflow and infiltration have an immense impact on the outcome of watershed practices. Thus, the gathering of biophysical data is an important step to understand the dynamics of the hydrological processes. This will help resource managers to formulate different strategies for different impacts. The hydrological investigation in the Bukit Timah area aims to establish the importance of the watersheds to maintaining water quality. Water samples were collected at three sites reflecting low, medium and high levels of human-related disturbances. Conductivity, pH, suspended sediment and the chemical composition of the water samples were analyzed to observe the different levels of hydrological responses to low, medium and high disturbances. This study shows that conductivity, suspended sediment and chemical concentrations of several elements are elevated in varying degrees by human-related activities. The elevated level of elements in the streams may reflect an increased rate of nutrient loss. The rise in conductivity, suspended sediment and chemical concentrations has caused a number of negative impacts. An increase in these parameters will result in a corresponding rise in treatment costs. Singapore has been relatively successful in the protection of catchment areas. Conservation measures are vital to ensure the quantity and quality of water supply. It is only prudent to protect the water resources as rising effluence and population will certainly put additional pressures on future water demands.