Ecohydrology in Indonesia: Emerging challenges and its future pathways

Abstract

The wealth of inland water resources and the endowed rich aquatic ecosystems in Indonesia are exposed to intertwined risk drivers, i.e. land use change related to the growing population and urbanization, and the adverse impacts of climate change. Recent advances in the wide range of applications of Ecohydrology aimed at sustainable use, reduction of risks and regulation of water and nutrient cycles from molecular to basin scale in Indonesia were developed and are presented. These vary from ecohydrological approach for the aquatic environmental management to obtain maximum benefit of the lake aquatic resources sustainably, through efforts to improve the aquatic carrying capacity, efforts to solve the water deficit due to land use change in the catchment area, and initial identification of several urban lakes in Jakarta Megacity area. An attempt to relate Ecohydrology and disaster risk reduction, especially the slowly approaching ecosystem disaster, is highlighted in view of addressing the emerging opportunities in Indonesia.

Introduction

Indonesia, like many other Asian countries, is experiencing a rapid economic development and it is projected to be one of the major economies in Asia. Indonesia ranks fourth (2010) in Asia (excluding South Asia and Oceania) in terms of its GDP, after China, Japan, and South Korea (World Bank, 2010). The economic growth and the implementation of the regional autonomy have taken, however, a considerable implication to the surrounding ecosystem integrity. The production of coal has not only driven the economic boom but also has adverse impact to the terrestrial environment, particularly the aquatic ecosystem. It has worsened the sedimentation impact on the rivers and lakes, and has accelerated the loss of biodiversity.

Human impact on sediment load in Asia has been described by Walling (2009), who mentioned that the key drivers can be land clearance, land-use activities and other forms of catchment disturbance. The sedimentation might be decreased by the use of sediment trapping by dams, soil conservation practices and sediment control programs, and sand extraction from river channels. Increased sediment loading comprises one of the most important and pervasive anthropogenic impacts on aquatic ecosystems globally. In spite of this, little is known about the overall effects of increased sediment loads on lakes. Also interactions with other global anthropogenic pressures, such as invasion by exotic species and climate change, are likely to be significant, however, little remains known about the nature or likely strength of those interactions. Widespread increases in sediment loading to lakes have, therefore, profound implications for the conservation and management of global aquatic biological diversity (Donohue and Molinos, 2009). Southeast Asia, wherein Indonesia occupies the largest portion, has the highest relative rate of deforestation of any major tropical region. Southeast Asia could lose three quarters of its original forests by 2100 and up to 42% of its biodiversity (Navjot et al., 2004). The drivers of biodiversity threat include forest conversion, forest fires, hunting for bushmeat, wildlife trade, and other potential drivers such as climate change, nitrogen deposition, invasive species and atmospheric CO₂ change.

Indonesia has benefited from inland waters – lake, rivers, wetlands, reservoirs – which provide supply water for everyday needs and livelihoods, foods from fishes, hydropower for electricity, and also for recreation. However, these functions have changed due to human activities affecting directly inland water ecosystems and also through the modifications of land use of the catchment areas or watersheds of inland water ecosystems. Indonesian lakes are facing many problems such as alteration in the physical habitat, sedimentation, eutrophication, organic pollution, cyanobacteria blooms and invasive species (Haryani, 2008).

Sedimentation, eutrophication and deterioration of water quality are the main problem of many lakes in Indonesia, including for example Lake Rawapening, that had induced lake shallowness (Soeprobowati, 2014). It was predicted that the lake might become land, due to heavy invasion of water hyacinth, Eichornia crassipes and other aquatic invasive plants, Hydrilla and Salvinia. Other lakes, like Lake Tondano and Lake Tempe, in Sulawesi Island, are seriously threatened by increasing siltation, water quality deterioration and deforestation in the catchment, which significantly reduced in -lake storage capacity (Hargono and Pranoko, 2003, Dam et al., 2001).

This paper outlines the issues on water, environment and societal development in Indonesia and how ecohydrology can capture the emerging opportunities, despite the huge challenges posed by the rapid development in the country. This will be preceded by exposing briefly the current ecohydrology research in Indonesia. Some explorative thinking will be proposed at the end, featuring the amalgamation of Ecohydrology and disaster management approach when dealing with ecological disaster as a creeping phenomenon.