The Influence of Human Activities on the Runoff Regime of Naolihe River
Using runoff data of 1956 ~ 2001 from the two hydrometric stations in the Naolihe River watershed, the seasonal and annual change in the runoff regime was analyzed, and the influence of human activities on the runoff was estimated. It was found that the seasonal distribution of runoff was quite uneven. The runoff from April to November accounted for 94.74% to 99.24% of the total. As to the long-term distribution in the runoff, the high-flow period was short (only 1 ~ 4 years), while the low-flow period was long (9 years). Comparison of uneven coefficients of annual distribution for the two hydrometric stations showed that the Cvy for the upstream runoff was 0.77 to 1.97, which was higher than that for the middle-stream runoff (0.62 ~ 1.32), while there was obvious increase in the Cvy for the middle-stream runoff, which indicated that the alteration in the runoff regime in the middle-stream area was more remarkable. Result of statistical analysis of stochastic hydrology showed that there was obvious decline in the runoff for the whole river. Analyses of double mass curve of annual runoff and precipitation showed that the decline in the runoff occurred in 1975 for the upstream runoff, and 1964 for the middle-stream runoff. The decline in runoff resulted from human activities such as reclamation of wetland, agricultural water use and so on. To assess the influence of human activities on the decline in the runoff, the correlations between precipitation and runoff for period without influence of human activities were established and used to estimate the natural runoff for period affected by human activities. The simulated results, compared with the monitored runoff data, demonstrated that decreases in runoff from human activities accounted for 71.19% of the total for the upstream, and 62.21% of total decrease in runoff for the middle-stream runoff. This showed that human activities, not annual precipitation, were the main driving forces that resulting in the decline of runoff in the Naolihe River. Affected by human activities, especially long term massive reclamation of wetland within the middle-stream area in the watershed, the natural runoff regime was altered remarkably, and the ecological environment of the watershed have been deteriorating in recent decades. For the sustainable developments of both social economy and eco-environment in the watershed, rational utilization and development of water resources and the protection of wetlands have become more and more urgent.
NETL
NSTL
万方数据
维普
