Study On Inconsistent Water Resources, Flood And Drought Problems In Changing Environment

Water is the source of life, a series of water problems were caused by the exploitation and utilization of water resources in recent years. The changing environment, namely the impact of climate change and intense human activities, which makes the physical background has been changed a lot and hydrological laws have been changed. The most serious effect of hydrological elements'physical variation is that the hydrological sequences lost their consistency and result in the hydrological alteration. The changing environment lead to the distortion of water resources evaluation and decision-making of flood control and drought judgment error, which seriously affected the social stability and economic progress. How to uncover the regulations of hydrological alteration in the inconsistent hydrological sequences and how to get frequency distribution effectively in changing environment are key issues in inconsistent water problems. In the article, the research study ideas of inconsistent water resources problem, inconsistent flood problem and inconsistent drought problem were introduced. The key issues were that inquired to frequency distribution and analyzed their laws.The research results of this article are as followings:(1) Research and summaryThe research meanings and background of inconsistent water resources, flood and drought problems in changing environment were introduced, and the research contents were proposed, based on the domestic and overseas study progress, the problem still exist and the research ideas were come up, the contents of this paper was put forward at the same time.(2) Time (or Scenarios) Planning for solving inconsistent hydrologic seriesThe thinking of time division way and the principle of scene classification were introduced on changing environment in the article. Hydrological variation diagnosis system is used to analyze the sequence variation diagnosis, according to variation diagnosis results (jumping or trend). The thinking and principle do not lost general, can be applied widely.(3) Cause analysis of runoff variationThe cause analysis methods of runoff variation were introduced, in this article, the "2-factor" method and "3-factor" method were put forward, which were used to analyzed the influence of human activities. The time scales runoff series (spring and winter, the flood season, and year) were selected, Heyuan station in Dongjiang river basin as an example, the good and bad of two methods were introduced in detail, the results showed that runoff variation come mainly from the impact of upstream human activities, the second is the influence of interval human activity.(4) The method of runoff frequency calculation based on runoff variation cause analysisSelection principle of caused analysis methods was that results conform to the actual situation. The inconsistent runoff frequency calculation for runoff in Heyuan station, from the perspective of genetic analysis, analyzed their laws, the results were shown that the water resources quantity was rising trend in different time scales (spring and winter, the flood season, and year). Combining the results of caused analyzed method, the rising trend was combined Longchuan station and interval runoff action.(5) The method of flood frequency calculation based on improved Muskingum modelThe method of flood frequency calculation based on improved Muskingum model which Combining the theory of multivariate regression and Muskingum model was put forward, the method intensifies the spatial relationships, combined with the inconsistency of hydrological frequency calculation principle, the past, the present and the future flood frequency distribution were calculated, and analyzed respectively he flood frequency calculation results, the comparison of different frequency flood level, typical flood return period of change, and the change of the interval probability. By analyzing main stream stations'(Heyuan, Lingxia and Boluo station) frequency distribution, we can found that the influence of flood is not land use change, but the building of reservoir.(6) Drought frequency analysis based on WHMLUCC model and Palmer drought severity indexAs a major natural disaster in China, drought is a restricting factor on the social and economic development. In the article, drought development process is simulated based on WHMLUCC model and Palmer drought severity index. A probability calculation method is proposed based on WHMLUCC model by the way of causes to inquire into the drought probability distribution on changing environment, and the drought event probability under different grade (such as non, light, medium, heavy and specially drought) is given, which could provide a scientific basis for drought forecasting and planning in the river basin. The results show that (1) the drought probability distribution shows a severe impact of climatic conditions on drought events, and LUCC has significant effects on drought on past climate condition, and LUCC has weak effects on present climate conditions;(2) comparing5scenarios, scenario2is beneficial to alleviate extreme drought, and the drought situation is relatively consistent on present climate condition, and (3)through cause analysis, it is known that the agricultural drought is closely related to climate change and the land use and land cover change in the Wudinghe River basin.