In order to track the footprint of groundwater science teaching and research in China during the past years,a bibliometric analysis was conducted based on the database of China National Knowledge Infrastructure (CNKI),which covered the time span from 1984 to present and included more than 2.6 million master and doctoral dissertations from hundreds of institutions of Mainland China. The bibliometric analysis summarized output,geographical,and institutional patterns,as well as research directions and hotspots in groundwater studies in China in the period of 1984-2014. A total of 1396 groundwater-related dissertations including 1161 master dissertations and 235 doctoral dissertations,contributed by 128 institutions distributed in 53 cities nationwide,were searched out in the database. It can be seen obviously that,the groundwater science teaching and research in China has experienced a notable growth in the past three decades especially during 2000-2014. Groundwater modeling,resource,and exploitation were the top three major subject categories; China University of Geosciences (Beijing),Jilin University and Chang’an University were the top three productive institutions together accounting for more than one third of the total dissertations and 50% of the doctoral dissertations,which further prompted the cities (Beijing,Changchun,and Xi’an) to become the top three productive cities. The dissertations generally covered all the international research topics,which indicated that hydrogeologists in China have tracked the international frontier closely during the past decades. The keywords analysis revealed that,(1) numerical modeling was still the hottest topic and PHREEQC,MODFLOW,GMS,and FEFLOW were the four most used softwares; (2) the topics related with groundwater pollution and quality developed steadily and rapidly; (3) environmental isotopes and GIS were frequently used tools for hydrogeological condition analysis,and spatial data processing respectively; and (4) the unsaturated zone as an integral part of aquifers attracted more and more attentions from hydrogeologists focus on saturated zone.

In order to track the footprint of the hydrogeology research in China during the past years, all the projects with the code of D0213 (hydrogeology, geothermic geosciences included) funded by the National Natural Science Foundation of China (NSFC) from 1997 to 2013 were searched and analysed. The statistics results showed that, a total of 88 institutes were ever funded with a total of 462 projects with the gross amount of 214 million yuan, and Beijing and Wuhan were the two most important centres for the hydrogeology research. In detail, A few 211 Project & 985 Project universities were the main forces, followed by Chinese Academy of Geological Sciences and Chinese Academy of Sciences. Apart from the several traditional geological universities/colleges (China University of Geosciences (Wuhan), China University of Geosciences (Beijing), Nanjing University, Jilin University, and Chang’an University) with outstanding performances, a few new forces from 211 Project & 985 Project universities also made good achievements with Beijing Normal University and Peking University standing out. Generally speaking, the focused scientific issues and related technologies included that but were not limited to, (1) Mechanism, control and remediation of groundwater/soil pollution were the most active fields, (2) Flow dynamics in saturated/unsaturated zone was still an interested topic, (3) Groundwater in hydrological cycle in different scales under climate change and human activities developed very quickly, (4) Engineering problems and disasters associated with groundwater aroused enormous attention,(5) Numerical modeling was still the most important means with wide application, and (6) Environmental tracing was a very active technique and new tracers were found and tried frequently.