Management of vegetative land for more water yield under future climate conditions in the over-utilized water resources regions: A case study in the Xiong’an New area

Abstract

Seeking more water yield in the over-utilized water resources regions that are home to nearly 35% of the population all over the world is a great challenge under future climate change. Impacts of land conversion (i.e., land conversion from cropland to grassland and forest) and climate change during near-future 2030s (2021–2040), mid-future 2050s (2041–2060), and far-future 2080s (2071–2090) periods on vegetation dynamics (LAI) and water budgets (evapotranspiration and runoff) were investigated in a typical over-utilized water resources area of China (Xiong’an New Area, XNA) using the WAVES ecohydrological model. Future climate change impacts were assessed with statistically downscaled forcing of 18 global circulation models (GCMs) under three representative concentration pathways (RCPs) using secondary bias-correction technique. Projected future climate indicated that XNA would become warmer and wetter in future. The WAVES model was calibrated against remotely sensed LAI and ET data. Modeling results during the historical period of 1982–2012 showed that forest evaporated more water (32.0 mm yr−1) than cropland, while grassland used almost the same amount of water as cropland. Under future climate conditions, both water use and water yield would increase in cropland and grassland due to increased precipitation. Forest was predicted to use 9.5–14.6% (36.4–55.8 mm yr−1) more water and to have 2.6-52.4% (2.6–51.1 mm yr−1) more water yield in the 2050s and 2080s under RCP4.5 and in all three future periods (2030s, 2050s, and 2080s) under RCP8.5 due to greater increases in precipitation. Afforestation is not recommended as a land management practice for more water yield in near-future, but could be implemented to achieve a win-win situation for more water yield and more forest coverage in mid- and far-future periods in XNA due to increased precipitation. This study highlights that uncertainties in projected future climate pose formidable challenges in management of vegetative land for more water yield in the over-utilized water resources regions.