Forestry Activities and Surface Water Quality in a Rainfall Watershed

The characteristics of water and water quality of the mainstream in a watershed can be directly affected by the ecological characteristics of the terrestrial ecosystem and indirectly affected by the species composition and structural change of the forests that interact. The most important causes of the structural changes are both silvicultural treatments and harvesting activities which can be considered as the main forestry activities. While water quality in a watershed is indirectly affected by forestry activities, especially harvesting activities, aquatic habitat can be also significantly affected. Due to the multifaceted interactions between terrestrial and aquatic ecosystems, this issue has not yet been clearly elucidated. Long-term studies on this subject at global scale have become widespread in recent years, which may guide the environmental and natural scientists to understand how the quality and characteristics of the prosperous water resources change with environmental influences. When the forestry activities are evaluated on the watershed basis, the flow regime of the mainstream changes while both the water temperature and the algal population increases, especially after the harvesting and thinning activities in riparian zones. In addition, there is an increase in the amount of sediment and organic matter transported to the main stream due to the decrease in forest vegetation in the watershed. That situation decreases water quality and negatively affects invertebrates, fish and other aquatic organisms. In this study, the impact of forestry activities on the quality of water resources and the indirect impact on the aquatic ecosystem was evaluated based on the relevant studies.