Abstract:

Based on the spatial and temporal distribution theory of basin, the evolution of the Nenjiang River basin runoff space-time laws was analyzed. And it focused on the attribution analysis of the factors of topography effect. Based on the precipitation data from 1955 to 2003(49 a) and runoff data from 1955 to 1973(19 a), the evolution of runoff, surface runoff and underground runoff were analyzed from upstream to downstream of the representa-tive hydrological stations. What the results shows is as follows: 1)In Nenjiang River basin，the inter-annual and space-time change of rainfall are consistent. So the impact of spatial and temporal distribution of precipitation can be ignored when runoff evolution is analyzed.2)The headwater differences from upstream to downstream can be determined through annual runoff evolution.The upstream is surface runoff. In the spring, the runoff is from snowmelt.  In the rainy season, it is from atmospheric precipitation. In the dry season, it comes from groundwater recharge. The downstream is mainly underground runoff.3)Because of slope and hydrogeological conditions, it is easier for upstream to produce flow. From upstream to downstream, the runoff volume is gradually reduced.

Key words: spatio-temporal changes of runoff, direct runoff, groundwater runoff, groundwater flow separation, Nenjiang River basin