Quantifying and mapping of water-related ecosystem services for enhancing the security of the food-water-energy nexus in tropical data–sparse catchment

Abstract

The food-water-energy nexus concept helps to produce an integrative solutions to secure the water-related ecosystem services sustainably. This study aims to quantify and map water provisioning and soil erosion regulating services from both demand and supply sides in a spatially explicit manner. It considers the Wabe River catchment of the Omo-Gibe Basin in tropical data-sparse region of East Africa as a case study and uses the Integrated Valuation of Ecosystem Services and Trade-offs (InVEST) annual and seasonal water yield and sediment delivery models. The water demands and biophysical parameters data were collected from primary and secondary sources and prepared according to the requirement of the models. The models output were validated after conducting sensitivity analysis of the input parameters. The result shows that the rainfall amount of the catchment is highly seasonal, which causes the surface water to vary according to the seasons. The high annual precipitation and low actual evapotranspiration of the catchment resulted high annual water yields. However, the people in the catchment did not satisfied their domestic water demand as result of inaccessibility and poor management of the rain water. The high net supply of water, especially in the rainy season, carries detached top soil via heavy rainfall in the upper catchment areas. Even though the existing land cover and management practices contribute to sediment retention, a large amount of sediment is exported to rivers, which jeopardizes the food and energy security. Thus, the management of water is essential for enhancing the security of the food-water-energy nexus in the catchment. The methods applied in this study can increase spatial understanding of the water-related ecosystem services especially in data-sparse catchments of the tropics, and lead to improvement of water management to enhance the security nexus.

Spatiotemporal Distribution and the Driving Force of the Food-Energy-Water Nexus Index in Zhangye, Northwest China

“…, x k are the independent variables. average temperature°C x 6 average precipitation mm x 7 average evaporation mm x 8 average altitude m transportation x 9 distance from each county to the main river m x 10 distance from each county to the main road m…”

“…As the most fundamental resources of economic and social development [1,2], food, energy, and water are closely interrelated [3][4][5][6][7][8][9]. With the growth of the population, urbanization and climate change as well as people's demand growing for food, energy and water, it is estimated that the nine billion people living on earth will need 30% more water, 40% more energy, and 50% more food to survive by 2030 [7,10,11].…”

“…Some scientists try to manage the water-energy-food nexus at the regional scale [11,26]. Some researchers quantify the water-energy-food nexus at the watershed scale [7,8,10,[27][28][29]. Li et al, Bai et al, and Wang et al analyzed China's water-energy-food nexus at the national scale [2,30,31].…”

Valuing Environmental Benefit Streams in the Dryland Ecosystems of Sub-Saharan Africa

“…Box 4. Case study: assessing water regulation and carbon sequestration using InVEST model (based on: Sahle et al [167,168] and others cited).…”

“…The anticipated effects on ecosystem service provision to be achieved through introducing agroforestry in the Wabe River catchment of the Gurage Mountain chain landscape, Ethiopia, over the period 2017-2030 have been modelled by Sahle et al [167,168] using the InVEST model [169]. Under a future land-use scenario with increased agroforestry, improvements could include increased food production (102%), water yields (17%) and carbon sequestration (19%), and reduced sediment export (21%) and soil loss (18%).…”