Assessment of the Impacts of Climate and LULC Changes on the Water Yield in the Citarum River Basin, West Java Province, Indonesia

Abstract

Changes in climate and land use land cover (LULC) are important factors that affect water yield (WY). This study explores which factors have more significant impact on changes in WY, spatially and temporally, within the Citarum River Basin Unit (RBU), West Java Province, Indonesia with an area of ±11.317 km2. The climate in the area of Citarum RBU belongs to the Am climate type, which is characterized by the presence of one or more dry months. The objectives of the study were: (1) To estimate a water yield model using integrated valuation of ecosystem services and tradeoffs (InVEST), and (2) to test the sensitivity of water yield (WY) to changes in climate variables (rainfall and evapotranspiration) and in LULC. The integration of remote sensing (RS), geographic information system (GIS), and the integrated valuation of ecosystem services and tradeoffs (InVEST) approach were used in this study. InVEST is a suite of models used to map and value the goods and services from nature that sustain and fulfill human life. The parameters used for determining the WY are LULC, precipitation, average annual potential evapotranspiration, soil depth, and plant available water content (PAWC). The results showed that the WY within the territory of Citarum RBU was 12.17 billion m3/year, with mean WY (MWY) of 935.26 mm/year. The results also show that the magnitude of MWY in Citarum RBU is lower than the results obtained in Lake Rawa Pening Catchment Areas, Semarang Regency and Salatiga City, Central Java (1.137 mm/year) and in the Patuha Mountain region, Bandung Regency, West Java (2.163 mm/year), which have the same climatic conditions. The WY volume decreased from 2006, to 2012, and 2018. Based on the results of the simulation, climatic parameters played a major role affecting WY compared to changes in LULC in the Citarum RBU. This model also shows that the effect of changes in rainfall (14.06–27.53%) is more dominant followed by the effect of evapotranspiration (10.97–23.86%) and LULC (10.29–12.96%). The InVEST model is very effective and robust for estimating WY in Citarum RBU, which was indicated by high coefficient of determination (R2) 0.9942 and the RSME value of 0.70.

Using InVEST to evaluate water yield services in Shangri-La, Northwestern Yunnan, China

“…There are differences in evapotranspiration, litter water retention, soil water content, and canopy interception among different vegetation types. Correspondingly, the different vegetation types show obvious differences in water yield capacity ( Nahib et al, 2021 ; Yang et al, 2021 ). Figure 6B shows the total water production among different vegetation types, indicating that although the average water yield of forests is relatively small, the forest area plays a major role in the water yield ecological service function in Shangri-La City given that forest occupies the largest area.…”

“…The map of annual reference evapotranspiration was generated based on the extraterrestrial radiation, temperature, and monthly average precipitation. The modified Hargreaves method was used to estimate the in areas with a lack of observed data ( Droogers & Allen, 2002 ), with estimates shown to be better than those of the Penman-Monteith method ( Nahib et al, 2021 ). The monthly and annual reference evapotranspiration maps were obtained through the ArcMap raster calculator, calculated as follows:…”

“…The advantages of the InVEST water yield model include strong spatial expression, dynamic evaluation capabilities, simple input data requirements, large output data volume, and strong scalability. Therefore, the model is widely used to: (1) evaluate the impact of land use on water-related ecosystem services ( Gao et al, 2017 ); (2) explore the impact of urbanization on water yield ( Xu et al, 2019 ); (3) analyze the effects of climate, topography, soil, land use types, and other factors on water yield ( Dai & Wang, 2020 ; Li et al, 2021b ; Nahib et al, 2021 ). The above studies demonstrated that the InVEST water yield model can reliably estimate the water yield ecosystem service in a wide range of catchment types.…”

Spatial and temporal distribution of estimated surface runoff caused by land use/land cover changes in the upstream Citarum watershed, West Java, Indonesia

“…The soil types in the study area are Inceptisols (80% of the total area) and Ultisols (20%) (Tanika et al, 2020). The upstream Citarum Watershed, known as Bandung Basin, has the Am climate type, characterized by one or more dry months annually (Nahib et al, 2021). A map of the study area is presented in Figure 1.…”

Impact of Climate and Land-Use Change on Groundwater Resources, Study of Faisalabad District, Pakistan

“…Previous studies have offered frameworks for assessing changes in groundwater resources. A recent study [16] on the impacts of climate on water resources reported that water yield, especially that controlled by evapotranspiration (ET) and precipitation, as well as land-use cover change caused by the human population, may indirectly affect available water resources. According to another study [17], groundwater recharge is affected by land-use change caused by anthropogenic activities, which also have a significant impact on groundwater flow dynamics.…”