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Karst spring water dynamic characteristics and its response to atmospheric precipitation are of great significance for water resources utilization under the background of climate change. This paper selects Longzici spring area, North China, as the study area. Based on a long series of spring water flow and precipitation data, the dynamic characteristics of spring flow were analyzed and the numerical simulation of the groundwater flow model was established. The results show that the groundwater kept the sustained decline over the past decades which is in a negative equilibrium state, with a storage variable of − 2.26 million m3/year. The sensitivity of spring flow to precipitation under different precipitation scenarios shows that the water level changes in the recharge and drainage areas are similar about (3–5 cm) and slightly larger than that in the runoff area(1.5 cm) when minimum rainfall (287.24 mm) happens. When the precipitation is at its maximum (867.66 mm), the water level change in the runoff area can reach 95 cm which is much larger than those in the recharge and discharge areas. The results indicate that Longzici karst spring has a relatively good regulation water resource capacity and the runoff area is more sensitive which plays an important role in response to climate change. [ABSTRACT FROM AUTHOR]

It is important that developing and utilizing of unconventional water resources such as pond water in the lowland area of North China Plain due to the shortage of fresh water resource. Thus, making clear the storage capacity of pond as irrigation water resources in years with different amount of precipitation and studying the relationship between precipitation and pond water storage are of great significance to the usages of multiple water resources in agriculture. Taking Nanpi County in Hebei Province as study area, this paper used the methods of Cl- and stable isotope balance to calculate the contribution of precipitation to pond water in rainy season. Besides, based on the Landsat TM remote sensing data during 2013- 2015, the improved normalized difference water body index was used to extract the pond information and analyze the water storage capacity of ponds in Nanpi County in years with different amount of precipitation. The results showed that precipitation is the main source of pond water, and the groundwater was the second source. According to the calculation of Cl- and stable isotope, precipitation accounts for 74.3%-86.0% of water supply for medium and small ponds during the rainy season in wet year, however, it accounts for only less than 30% of water supply for large ponds. The ponds are mainly small ponds with area less than 0.5 hm2. The number and the water storage area of ponds with different areas changed with precipitation. The water storage capacity of ponds in flat water year, dry year and wet year were 1.49×107, 0.84×107 and 1.90× 107 m3, respectively. The results provide important infromation for the pond water management and utilization in the lowland area of North China Plain. [ABSTRACT FROM AUTHOR]

Summary: In this paper, the trends of the annual streamflow and precipitation and cross correlations between them were analyzed in nine large river basins of China during 1956–2005. The results indicate that: (1) the annual mean streamflow decreases in arid and semi-arid regions of north China; however, increasing trends occur in south and Southwest China; (2) the annual streamflow and precipitation exhibit reasonable correlation in nine large river basins except those located in inland areas. The annual streamflow over most areas of China is fed by precipitation; however, the decline in streamflow is faster than the decreases of precipitation since 1970s in the arid and semi-arid regions of north China. The relationship between the annual precipitation and streamflow presents a non-stationary state in north China. This non-stationary relationship is strongly influenced by both human activities and precipitation changes; (3) a significant increase of water use might be the major factor responsible for the steeper decline in streamflow than in precipitation in Haihe River, Yellow River and Songliao River basins in north China. In inland river areas, increase of water use and actual evapotranspiration might result in decline in streamflow although precipitation has an increase tendency. This paper sheds light on the non-stationary relationship between annual precipitation and streamflow and possible underlying causes, which will be helpful for a better understanding of the changes of precipitation and streamflow in China at large scale and in other regions of the world. [Copyright &y& Elsevier]