Wetland degradation monitoring using multi-temporal remote sensing data and watershed land degradation index

Abstract

BACKGROUND AND OBJECTIVES: The condition of the watershed area, particularly the Tabunio Watershed, is one with priority treatment due to the condition of the land where it is located, which qualifies for the “very high recovery” category with a critical land area of 19,109.89 hectare. Moreover, the diminishing water absorption also results in flooding during the rainy season and drought in the dry season. Environmental damage in the Tabunio Watershed is exacerbated by the existence of traditional gold mining and has become a concern for many parties. With this in mind, the perceived increase in natural disasters, such as floods, landslides, and droughts from year to year requires an evaluation of land degradation in the Tabunio Watershed.METHODS: The objective of this study was to monitor and simulate the spatial and temporal aspects of land degradation in the Tabunio Watershed. It was suggested that a complete land degradation index be developed to capture the spatial and temporal aspects of land degradation between the years 2005 and 2020. This index integrates land use land cover, vegetation coverage, soil erosion, and soil moisture content.FINDINGS: The proposed comprehensive land degradation index in this study demonstrated that (a) the land degradation index, which successfully monitored the spatio-temporal aspect of land degradation (kappa coefficient > 0.73 and overall accuracy > 86 percent), is regarded as having high accuracy. (b) In comparison to the individual indices, the land degradation index is capable of revealing land degradation in a more comprehensive manner. (c) land degradation index is readily transferable and applicable to other study areas due to the fact that all of its land degradation indices can be quickly extracted from remotely sensed imagery. (d) land degradation index can be used in a wide variety of contexts, which also accounts for the provision of quantitative predictions with regard to the possibility of land degradation. (e) The rate of land degradation will generally increase from 2005 to 2020, with 2010 being the most extreme year.CONCLUSION: The proposed comprehensive land degradation index method is capable of describing the spatial and temporal aspect of land degradation from 2005 to 2020 in the watershed area. Moreover, the proposed approach shows that the level of land degradation from 2005 to 2020 normally increases, recording the extreme years as the 2010s. In addition, in most years, the amount of land degradation was moderate, only few of which had severe or extreme degradation. As a consequence of this, some land degradation management measures ought to be created in advance, guaranteeing the protection of this vital region, which is a source of freshwater. The study provides a substantial understanding of the effect of land degradation on sustainable environment management and development in the watershed.

Keywords

• land degradation index
• land use/land cover (lulc)
• soil erosion
• soil moisture content
• vegetation coverage