Hydrology has a long history due to its early origin, but it is still considered young due to lack of a solid scientific foundation as a natural science. To lay a solid foundation of hydrology, field experimentation is crucial for investigating hydrological processes and revealing hydrological mechanisms. Professor Wei-Zu Gu (1932–2022) was an internationally renowned scientist in the field of hydrology and is recognized as the greatest pioneer of experimental hydrology and isotope hydrology in China. He created the Hydrohill experimental catchment, which serves as both a great public works for experimental hydrology and a valuable legacy for future researchers to conduct hydrological experiments. This legacy represents an innovative infrastructure that bridges the gap between natural watershed experiments and artificial physical models. The Hydrohill is an intensively-instrumented experimental catchment, allowing for comprehensive measurement of elements of the hydrologic cycle and their tracing indicators in a sophisticated manner. To provide an in-depth understanding of the Hydrohill, this paper presents its short history, experimental objectives, site description (including location, construction, and instrumentation), site conditions (such as soil, hydrological and meteorological properties), and contributions to hydrologic science. We pay our respects to Professor Gu for his hard work in creating the Hydrohill for experimental hydrology and enhancing our understanding of hydrological processes and mechanisms. Finally, we hope that with healthy operation at Chuzhou Scientific Hydrology Laboratory (CSHL) along with support from Professor Gu’s friends, CSHL will enable the continued growth of the Hydrohill so that it can address some unsolved problems in hydrology.

Alpine basins are essential to the conservation of water resources. However, they are typically poorly gauged and inaccessible, owing to the harsh prevailing environment and complex terrain. To investigate the influences of different precipitation inputs on hydrological modeling in alpine basins, two representative satellite precipitation products [Tropical Rainfall Measuring Mission (TRMM) and Integrated Multi-Satellite Retrievals for GPM (IMERG)] and two reanalysis precipitation products [China Meteorological Assimilation Driving Datasets for the SWAT model (CMADS) and Climate Forecast System Reanalysis (CFSR)] in the Yellow River Source Region (YRSR) were selected for evaluation and hydrological verification against gauge-observed data (GO). Results indicates that the accuracy of these precipitation products in the warm season is higher than that in the cold season, and IMERG has the best performance, followed by CMADS, CFSR, and TRMM. TRMM seriously overestimates high rainfall of greater than 10 mm/day. CFSR overestimates moderate precipitation events of 1–10 mm/d, while CMADS underestimates the effects of precipitation events of 1–20 mm/d. Models using the GO as input yielded satisfactory performance during 2008–2013, and precipitation products have poor simulation results. Although the model using IMERG as input yielded unsatisfactory performance during 2014–2016, this did not affect the use of IMERG as a potential data source for YRSR. After bias correction, the quality of CFSR improves significantly with R2 and NSE increasing by 0.25 and 0.31 at Tangnaihai station, respectively. Model driven by the combination of GO and CMADS precipitation performed the best in all scenarios (R2 = 0.77, NSE = 0.72 at Tangnaihai station; R2 = 0.53, NSE = 0.48 at Jimai station). These results can provide reference data, and research ideas, for improved hydrological modeling of alpine basins.