Response of karst springs to climate change and anthropogenic activities: the Niangziguan Springs, China

Discharge from the largest karst spring in north China, the Niangziguan Springs, has been declining since the 1950s. This paper examines the response of these springs to climatic change and anthropogenic infl uence by attempting a model-based discrimination between phases in the stream discharge record. In Niangziguan Springs Basin, the exploitation of karst groundwater began in 1979. Accordingly, the spring discharge data were divided into two phases: pre-1979 and post-1979. In the fi rst phase (1957–78) the spring discharge was believed to be affected solely by climate change, and in the second phase (1979–2007) the spring discharge was infl uenced by both climate change and human activities. Using grey system theory, a discharge model was estimated for the fi rst phase. Extrapolating the model, we obtained a projection of the spring discharge during the second phase. Using a water balance calculation, we discerned the respective effects of climate © The Author(s), 2009. Reprints and permissions: http://www.sagepub.co.uk/journalsPermissions.nav *Author for correspondence. Email: [email protected], [email protected] at UNIV ARIZONA LIBRARY on October 14, 2010 ppg.sagepub.com Downloaded from Yonghong Hao et al.: Response of karst springs to climate change and anthropogenic activities 635 change and human activities on depletion of spring discharge for the second phase. The results show that the contribution of climate change to depletion of Niangziguan Springs is 2.30m3/s and the contribution of anthropogenic activities ranges from 1.89 to 2.90 m3/s, although this assumes a constant for the climate change effect. Accordingly, the anthropogenic effects have been approaching and surpassing the effects of climate change during the second phase. With respect to the impact of human activities on spring discharge, groundwater abstraction accounts for only about 34–52% of the declines; 48–66% of the declines are related to other human activities, such as dewatering from coal mining, dam building and deforestation.