Evaluation of the water conservation function in the Ili River Delta of Central Asia based on the InVEST model

CAO Yijie, MA Yonggang, BAO Anming, CHANG Cun, LIU Tie

Table 1 Description of data sources and parameter processing methods used in this study

Data type Unit Data source/Parameter processing method Precipitation mm The CRU TS4.04 data (1975-2020), a global annual precipitation dataset at the resolution of 0.5°×0.5° (http://data.ceda.ac.uk/badc/cru/data/cru_ts/). Potential evapotranspiration mm The ERA5 data (1975-2020), a global annual evapotranspiration dataset at the resolution of 0.1°×0.1° (https://www.ecmwf.int/en/research/climate-reanalysis). Land use data - The dataset (1990, 2010, 2015, and 2020) was provided by the Data Center for Resources and Environmental Sciences, Chinese Academy of Sciences (RESDC) (http://www.resdc.cn). Soil depth mm HWSD version 1.1 soil data (2009) (https://data.apps.fao.org/). Root depth mm Canadell et al. (1996); Sharp et al. (2018). Biophysical table - The InVEST model. PAWC - PAWC is the difference between the field water holding capacity and permanent wilting coefficient, which was calculated by empirical equations using data including the percentages of sand, silt, and clay, and organic matter content based on the HWSD version 1.1 soil data (Wang et al., 2021b). Velocity coefficient - Referring to the InVEST model manual (Sharp et al., 2018). Topographic index - Calculated from soil depth, percentage slope, and drainage area data. Percentage slope % Percentage slope was based on DEM and calculated using the slope tool in ArcGIS. Drainage area - Drainage area was based on DEM and calculated using the slope tool in ArcGIS. Soil saturation conductivity mm/d Soil saturation conductivity was calculated in the Neuro Theta model using soil clay, silt, and coarse sand mass fractions based on the HWSD version 1.1 soil data (Li et al., 2022a). Runoff m3 The discharge observation data (1975-2020) at hydrological stations along the Ili River were collected from the National Cryosphere Desert Data Center (http://www.ncdc.ac.cn). NDVI - National Aeronautics and Space Administration (https://ladsweb.nascom.nasa.gov/search/) (1990-2020). DEM m United States Geological Survey (https://www.usgs.gov/) (2020). Water level m The water level data (1975-2020) of the Lake Balkhash were from Jason 1/2/3 altimetry satellite data (United States Geological Survey, https://earthexplorer.usgs.gov/) and studies of Nakayama et al. (1997) and Long et al. (2011).