The Jinan karst spring system, discharged by 108 springs in 2.6 km² city center area of Jinan, China, has been suffering lower regional groundwater levels, which threatens the karst springs outflowing and aquatic ecological civilization. For better spring protection, monthly hydrogeochemical and isotopic investigations were conducted in four representative karst springs (Baotu Spring (BTQ), Heihu Spring (HHQ), Zhenzhu (ZZQ), and Wulongtan Springs (WLT)) in 2016. Results showed that the BTQ, WLT, and ZZQ had similar hydrogeochemical and isotopic behaviors, which were different with that of HHQ. By combining the daily water level data with monthly hydrogeochemical and isotopic data of BTQ and HHQ, the hydrogeological processes of the two neighboring karst springs (470 m apart) are distinguished. (a) BTQ is recharged by two sources of precipitation and river water, while HHQ is recharged mainly by precipitation. (b) Hydrogeochemical characteristics of Baotu Spring are mainly controlled by calcite, dolomite, and gypsum dissolution mixture with river water and agricultural activity, while the hydrogeochemical characteristics of Heihu Spring are mainly controlled by calcite, dolomite, and gypsum dissolution in dry season, and dilution in wet season. (c) The discharge component of both springs is storage water by diffuse flow which is pressured by new infiltration rain water. The ratio of rain water is 14% in Baotu Spring and 9% in Heihu Spring calculated by a binary mixture model. Overall, this study puts forward the standpoint that neighboring karst springs with the same geological condition, can show different hydrogeological characteristics, which is a useful evidence for understanding the heterogeneity/complexity of karst aquifers.

Groundwater storage (GWS) in the Haihe River Basin (HRB), which is one of the most densely populated and largest agricultural areas in China, is of great importance for the ecosystem environment and socio-economic development. In recent years, large-scale overexploitation of groundwater in HRB has made it one of the global hotspots of GWS depletion. In this study, monthly GWS variations in HRB from 2003 to 2020 were estimated using the Gravity Recovery and Climate Experiment (GRACE) and GRACE Follow-On (GRACE-FO) data in combination with three land surface models (LSMs) from the Global Land Data Assimilation System (GLDAS). The results show the following: (1) HRB suffered extensive GWS depletion from 2003 to 2020, which has been aggravated since 2014, with a mean rate of 1.88 cm·yr⁻¹, which is equivalent to a volume of 6 billion m³·yr⁻¹. The GWS depletion is more serious in the plain zone (−2.36 cm·yr⁻¹) than in the mountainous zone (−1.63 cm·yr⁻¹). (2) Climate changes are excluded from the reasons for GWS depletion due to annual precipitation and evaporation being close to normal throughout the period. In addition, GWS changes show a low correlation with meteorological factors. (3) The consumption of groundwater for irrigation and land use/cover changes have been confirmed to be the dominant factors for GWS depletion in HRB. (4) The effects of inter-basin water transfer projects cannot be obviously observed using the GRACE and GRACE-FO; more inter-basin water transfers are needed for recovering the GWS in HRB. Therefore, it is imperative to control groundwater exploitation and develop a more economical agricultural irrigation structure for the sustainability of groundwater resources in HRB.

Water chestnuts (Trapa) are frequently recovered at Neolithic sites along the Lower Yangtze River Valley and have been important components of the diets of prehistoric people. However, little systematic research has been conducted to determine their cultural and dietary importance. Excavations at the Tianluoshan site produced large quantities of well-preserved specimens, which provide an excellent collection for studying morphological changes with time. Using modern wild and domesticated water chestnuts (n = 447) as a reference, we find Neolithic samples (n = 481) at Tianluoshan are similar in shape but smaller in size compared to the domesticated species Trapa bispinosa. In particular, the Tianluoshan water chestnuts have bigger seeds than the wild species Trapa incisa. Further, water chestnuts diachronically increased in size at the Tianluoshan site with significant differences (one-way, ANOVA) observed for length (p = 7.85E-08), height (p = 3.19E-06), thickness (p = 1.2E-13), top diameter (p = 5.04E-08) and bottom diameter (p = 1.75E-05) between layers 7 (6700-6500 cal BP) and 6 (6500–6300 cal BP). These results suggest that water chestnuts were actively selected based on size (big), shape (full fruit, two round horns, wide base, etc.) and were an important non-cereal crop to the agricultural practices at the Tianluoshan site.

Quantitative assessment of the terrestrial water storage (TWS) changes and the major driving factors have been hindered by the lack of direct observations in Inner Mongolia, China. In this study, the spatial and temporal changes of TWS and groundwater storage (GWS) in Inner Mongolia during 2003–2021 were evaluated using the satellite gravity data from the Gravity Recovery and Climate Experiment (GRACE) and the GRACE Follow On combined with data from land surface models. The results indicated that Inner Mongolia has experienced a widespread TWS loss of approximately 1.82 mm/yr from 2003–2021, with a more severe depletion rate of 4.15 mm/yr for GWS. Meteorological factors were the driving factors for water storage changes in northeastern and western regions. The abundant precipitation increased TWS in northeast regions at 2.36 mm/yr. Anthropogenic activities (agricultural irrigation and coal mining) were the driving factors for water resource decline in the middle and eastern regions (especially in the agropastoral transitional zone), where the decrease rates were 4.09 mm/yr and 3.69 mm/yr, respectively. In addition, the severities of hydrological drought events were identified based on water storage deficits, with average severity values of 17 mm, 18 mm, 24 mm, and 33 mm for the west, middle, east, and northeast regions, respectively. This study established a basic framework for water resource changes in Inner Mongolia and provided a scientific foundation for further water resources investigation.