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1.
Debris flow is a common natural hazard in the mountain areas of Western China due to favorable natural conditions,and also exacerbated by mountainous exploitation activities.This paper concentrated on the characteristics,causes and mitigation of a catastrophic mine debris flow hazard at Longda Watershed in Songpan County,Sichuan Province,on 21 July 2011.This debris flow deposited in the front of the No.1 dam,silted the drainage channel for flood and then rushed into tailing sediment reservoir in the main channel and made the No.2 dam breached.The outburst debris flow blocked Fu River,formed dammed lake and generated outburst flood,which delivered heavy metals into the lower reaches of Fu River,polluted the drink water source of the population of over 1 million.The debris flow was characterized with a density of 1.87~2.15 t/m 3 and a clay content of less than 1.63%.The peak velocity and flux at Longda Gully was over 10.0~10.9 m/s and 429.0~446.0 m 3 /s,respectively,and the flux was about 700 m 3 /s in main channel,equaling to the flux of the probability of 1%.About 330,000m 3 solid materials was transported by debris flow and deposited in the drainage tunnel(120,000~130,000 m 3),the front of No.1 dam(100,000 m 3) and the mouth of the watershed(100,000~110,000 m 3),respectively.When the peak flux and magnitude of debris flow was more than 462 m 3 /s and 7,423 m 3,respectively,it would block Fu River and produce a hazard chain which was composed of debris flow,dammed lake and outburst flood.Furthermore,the 21 July large-scale debris flow was triggered by rainstorm with an intensity of 21.2 mm/0.5 h and the solid materials of debris flow were provided by landslides,slope deposits,mining wastes and tailing sediments.The property losses were mainly originated from the silting of the drainage tunnel for flash flood but not for debris flow and the irrational location of tailing sediment reservoir.Therefore,the mitigation measures for mine debris flows were presented:(1) The disastrous debris flow watershed should be identified in planning period and prohibited from being taken as the site of mining factories;(2) The mining facilities are constructed at the safe areas or watersheds;(3) Scoria plots,concentrator factory and tailing sediment reservoir are constructed in safe areas where the protection measures be easily made against debris flows;(4) The appropriate system and plan of debris flow mitigation including monitoring,remote monitoring and early-warning and emergency plan is established;(5) The stability of waste dump and tailing sediment reservoir are monitored continuously to prevent mining debris flows.  相似文献   

2.
１ＩＮＴＲＯＤＵＣＴＩＯＮＳｅｖｅｒｅｗａｔｅｒｐｏｌｕｔｉｏｎａｎｄｗａｔｅｒｒｅｓｏｕｒｃｅｓｓｈｏｒｔａｇｅｓｈａｖｅｂｅｃｏｍｅｔｗｏｋｅｙｏｂｓｔｒｕｃｔｉｏｎｓｔｏｒｅａｌｉｚｅｓｕｓｔａｉｎａｂｌｅｕｔｉｌｉｚａｔｉｏｎｏｆｗａｔｅ...  相似文献   

3.
Rock weathering plays an important role in studying the long-term carbon cycles and global climatic change. According to the statistics analysis, the Huanghe (Yellow) River water chemistry was mainly controlled by evaporite and carbonate weathering, which were responsible for over 90% of total dissolved ions. As compared with the Huanghe River basin, dissolved load of the Changjiang (Yangtze) River was mainly originated from the carbonate dissolution. The chemical weathering rates were estimated to be 39.29t/(km2·a) and 61.58t/(km2·a) by deducting the HCO 3 − derived from atmosphere in the Huanghe River and Changjiang River watersheds, respectively. The CO2 consumption rates by rock weathering were calculated to be 120.84×103mol/km2 and 452.46×103mol/km2annually in the two basins, respectively. The total CO2 consumption of the two basins amounted to 918.51×109mol/a, accounting for 3.83% of the world gross. In contrast to other world watersheds, the stronger evaporite reaction and infirm silicate weathering can explain such feature that CO2 consumption rates were lower than a global average, suggesting that the sequential weathering may be go on in the two Chinese drainage basins. Foundation item: Under the auspices of Ministry of Science and Technology Project of China (No. G1999043075) Biography: LI Jing-ying (1974-), female, a native of Xinye of Henan Province, Ph.D., associate professor, specialized in environmental geochemistry. E-mail: wxxljy2001@public.qd.sd.cn  相似文献   

4.
In recent years,wetland ecological water requirements (EWRs) have been estimated by using hydrological and functional approaches,but those approaches have not yet been integrated for a whole ecosystem.This paper presents a new method for calculating wetland EWRs,which is based on the response of habitats to water level,and determines water level threshold through the functional integrity of habitats.Results show that in the Huanghe (Yellow) River Delta water levels between 5.0 m and 5.5 m are required to maintain the functional integrity of the wetland at a value higher than 0.7.One of the dominant plants in the delta,Phragmites australis,tolerates water level fluctuation of about ± 0.25 m without the change in wetland functional integrity.The minimum,optimum and maximum EWRs for the Huanghe River Delta are 9.42×106 m3,15.56×106 m3 and 24.12×106 m3 with water levels of 5.0 m,5.2 m and 5.5 m,corresponding to functional integrity indices of 0.70,0.84 and 0.72,respectively.A wetland restoration program has been performed,which aims to meet these EWRs in attempt to recover from losses of up to 98% in the delta's former wetland area.  相似文献   

5.
I.INTRODUCTIONThearidlandinNorthwestChina,richinlight,heat,landandmineralresources,isoneofthebiggestpotentialregionsforeconomicdevelopmentinthefuture.Itischaracterizedbydroughtclimate,scarceprecipitationandthereisnoagriculturewitholltirrigation(Liu,1980).Waterisnotonlythemostvaluablenaturalresources,butalsoveryimportantenvironmentalfactorinthisarea.Theoasesandwaterresourcesforhumansurvivalanddevelopmentaredistributedmainlyintheinlandriverbasins.Atpresentexploitationandutilizationofwater…  相似文献   

6.
ＣＯＮＴＥＮＴＡＮＤＤＩＳＴＲＩＢＵＴＩＯＮＯＦＴＲＡＣＥＥＬＥＭＥＮＴＳＩＮＳＯＩＬＳＯＦＴＨＥＤＡＭＲＩＶＥＲＡＮＤＴＵＯＴＵＯＲＩＶＥＲＢＡＳＩＮＳ￥ＳｈａｏＱｉｎｇｃｈｕｎ（邵庆春）ＤｅｎｇＷｅｉ（邓伟）ＳｕｎＧｕａｎｇｙｏｕ（孙广友）（Ｃｈ...  相似文献   

7.
In Taihu Lake basin during June–July in 1991, there happened a catastrophic flood, the precipitation reached that of 1954 and the water level was the highest in the history in Taihu Lake. This heavy flood, happening in the relatively humid period and being well accord with flood-drought change tendency, was early precautioned. The occurrence of the flood illustrated that using records of historical climate to predict flood-drough tendency is practically significant for hazard-reduction project.  相似文献   

8.
ＧＥＯＧＲＡＰＨＩＣ ＥＮＶＩＲＯＮＭＥＮＴ ＣＨＡＮＧＥ ＡＮＤ ＦＬＯＯＤ ＣＡＴＡＳＴＲＯＰＨＥ ＩＮ ＨＵＡＩＨＥ ＲＩＶＥＲ ＢＡＳＩＮ ＤＵＲＩＮＧ ＬＡＳＴ ２０００ ＹＥＡＲＳＹａｎｇＤａｙｕａｎ（杨达源）（ＤｅｐａｒｔｍｅｎｔｏｆＧ...  相似文献   

9.
Ma  Yanyan  Li  Guangxue  Ye  Siyuan  Zhang  Zhiheng  Zhao  Guangming  Li  Jingyang  Zhou  Chunyan  Ding  Wenjie  Yang  Xin 《中国海洋湖沼学报》2010,28(6):1362-1370
The water and sediment discharge regulation (WSDR) project, which has been performed since 2002 before flood season every year, is of great significance to the river management in China. Until 2007, six experiments have been fulfilled to evaluate the effect of the project on the natural environment. To fill the gap of investigations, a study on flood and suspended sediment transportation and channel changing along the distributary channel of the Huanghe (Yellow) River was conducted during the WSDR project period in 2007. The lower channel was scoured rapidly and the channel became unobstructed gradually several days after the flood peak water was discharged from the Xiaolangdi Reservoir. Within four days after the flood peak at 3 000 m3/s entered the distributary, the channel in the river mouth area was eroded quickly. Both the mean values of area and depth of the main channel were tripled, and the maximum flood carrying capacity increased to 5 500 m3/s or more. Then, the river channel was silted anew in a very short time after completion of the WSDR. Favored by the WSDR project, the river status in April 2008 became better than that of the year before. The adjustment ranges of main channel parameters were about 30%, 10%, and 10% at sections C2, Q4, and Q7, respectively. The process of rapid erosion-deposition was more active 15 km away in the channel from the river mouth due to the marine influence. It is reasonable for discharging sediment at concentration peak from Xiaolangdi Reservoir at the end of the flood peak. As a result, the sediment peak reached the river mouth about two days later than that of the water current. In addition, the WSDR project has improved the development of the estuarine wetland. Wetland vegetation planted along the river banks restrained the water flow as a strainer and improved the main channel stability. It is suggested to draw water at mean rate of 150 m3/s from the Huanghe River during flood periods, because at the rate the water in the wetland would be stored and replenished in balance. Moreover, we believe that cropland on the river shoal of the lower Huanghe River should be replaced by wetland. These activities should achieve the Huanghe River management strategy of “To concentrate flow to scour sediment, stabilize the main channel, and regulate water and sediment”.  相似文献   

10.
This paper presents a paleoflood study to determine the flood frequency of the Changjiang River, based on core cj0702, taken from the Changjiang River subaqueous delta. We identified flood deposits by means of high-resolution grain-size variation, sensitive population, geochemical indexes and magnetic susceptibility. The core covers a time span of 120 years by 210 Pb dating and was sampled at 1–2 cm intervals. Grain size, geochemical elements, and physical parameters were analyzed. The results indicate that the sediment of the core is mainly composed of silt and clay, as well as groups of interbedded silt, clay silt, and clay. Vertically, the grain size pattern was controlled by seasonal variations in water discharge and by the sediment input in winter from the abandoned Huanghe River delta. River flooding caused extreme values in all our measured parameters. We identified more than 20 flood events that occurred since 1887 using the physical parameter analysis method. The environmentally sensitive component of sediment grain size(14.32–96.39 μm) contribution30%, Zr/Rb ratio1.5, and magnetic susceptibility16 were selected as the criteria for flood identification generally. We also found that floods that had taken place in the upstream, midstream, or downstream parts of the river were clearly identified by these indexes while the large-scale floods that covered the whole drainage area did not leave clear indications in the sediment record. This study for identification of flood events is of great significance for understanding hyperpycnal current sedimentation as well as for forecasting of floods.  相似文献   

11.
ＴＨＥ ＡＰＰＬＩＣＡＢＩＬＩＴＹ ＯＦ ＲＥＳＥＡＲＣＨ ＯＮ ＦＬＯＯＤ－ＤＲＯＵＧＨＴ ＴＥＮＤＥＮＣＹ－ＡＮ ＡＮＡＬＹＳＩＳ ＯＮ ＤＩＳＡＳＴＲＯＵＳ ＦＬＯＯＤ ＯＦ ＴＡＩＨＵ ＬＡＫＥ ＢＡＳＩＮＩＮ ＪＵＮＥ－ＪＵＬＹ，１９９１ ...  相似文献   

12.
The Chinese people began to research the main source of the Changjiang (Yangtze) River 2,400 years ago. Limited by the scientific level, they did not discover it. The Tuotuo River was determined as the main source of the Changjiang River in the 1970s. However, this was not correct, because when comparing the length of the Tuotuo River with the Dam River, the glacier length at the headwaters was added to the Tuotuo River, resulting in that the Tuotuo River is 1 km longer than the Dam River, keeping in mind that the glacier can not be regarded as part of the river. In the summer of 1986, we investigated the source of the Changjiang River, we accurately measured the length of both the Tuotuo and Dam rivers, we discovered that the Dam River was 353.1 km long, and the Tuotuo River was 346.3 km long, the Dam River thus being 6.8 km longer than the Tuotuo River. The discharge of the Dam River is 196.18 m3/sec., 2.6 times as large as that of the Tuotuo River, that of the Tuotuo River is 75.10 m3/ sec. The drainage area of the Dam River is 1.8 times as larger as that of the Tuotuo River; the drainage area of the Dam River is 30,715.7 km2, the Tuotuo River is 16,691.0 km2. Through synthetic analysis of the factors mentioned above, we came to the conclusion that the main source of the Changjiang River is the Dam River instead of the Tuotuo River.  相似文献   

13.
The research on the present situation of soil and water development and utilization in Shiyang River Basin shows that water resources and eco-environment situation in this area are near the edge of collapse. Since the water crises occurred in the 1970s, problems caused by continuous decrease of water resources have been becoming serious year by year and eco-environment crisis occurred as a consequence. Up to now, 10 380ha of irrigated lands have been abandoned due to sand coverage and water shortage in the basin. Ground water was over exploded in Wuwei and Minqin because of water shortage. Ground water table in many places dropped under 5m (which is the ecology water table level), thus about 3000ha of Elaeagnus angustifolia forest come to dead and another 5800ha become feeble, and wind-drift sand near the oasis become alive. According to the current situation, if water utilization scope was not enlarged, a water transfer volume of 600×106m3/a from other areas will be suitable to keep water resources and eco-environment safety in the basin, and also 70×106m3/a will be left as spare water. Under this condition the water resources and eco-environment of the basin can reach the critical safety line of 2.032×109m3/a; or if 180×106m3 of water can be transferred from other areas, the water resources can reach the safety warning line of 1.732×109m3/a. Foundation item: Under the auspices of the National Natural Science Foundation of China (No. 40235053) and Lanzhou Jiaotong University "Qinglan" Foundation Biography: ZHANG Ji-shi (1963-), male, a native of Tongwei of Gansu Province, senior engineer, specialized in water resources and climate change in Northwest China. E-mail: zjs1963@yahoo.com.cn; hangjs@mail.lzjtu.cn  相似文献   

14.
In this study, the differences in annual rainstorm changes in the Second Songhua River Basin and the Nenjiang River basin and their causes were compared from the perspective of mountain effects. The following results were drawn: (1) Altitude effect is the primary factor leading to increased rainstorms in the southern source; (2) Slope effect primarily leads to differences of the weather systems in the two sources, and thus cause the difference of the rainstorms; (3) Slope effect is responsible for the greater fluctuation in the observed floods in the southern source. These landform differences eventually lead to the differences in the characteristics of floods in the southern and northern sources. Commensurability method was used to identify the period of rainstorms in the southern and northern sources. The results showed that although rainstorms do not appear at the same time in the two sources they are characteristic of a 10 years’ period in both areas. These results can serve as hydrological references for flood control and long-term flood disaster predictions.  相似文献   

15.
The mega debris flow occurred on August 13 th 2010 in Qingping town,China(hereafter called ’8.13’ Debris Flow) have done great damage to the local habitants as well as to the re-construction projects in the quake-hit areas,and the channel-fill deposit problem caused by the debris flow was the most destructive.Moreover,it is of high possibility that an even severe deposit problem would reappear and result in worse consequences.In order to maximize risk reduction of this problem,relevant departments of the government established a series of emergency river restoration schemes,for which the numerical analysis is an important procedure to evaluate and determine the optimized one.This study presents a numerical analysis by applying a twodimensional debris flow model combined with a relevant water-sediment model to simulate the deposit during the progress of the debris flow,and to calculate and analyze the river flow field under both the present condition and different restoration conditions.The results show that the debris flow model,which takes the confluence of the Wenjia Gully to the main river into account,could simulate the deposit process quite well.In the reproduced debris flow from the simulation of the ’8.13’ Debris Flow,the original river flow path has switched to a relatively lower place just along the right bank with a high speed of near 7m.s-1 after being blocked by the deposit,which is highly hazardous.To prevent this hazard,a recommended scheme is derived through inter-comparison of different restoration conditions.It shows that the recommended scheme is able to reduce the water level and as well to regulate the flow path.Based on the given conditions of the mainstream and the tributary confluence for the simulated ’8.13’ Debris Flow,when encountering a debris flow with deposit volume less than 0.5 million m3,the river channel can endure a 20-year return flood;however,when the deposit volume increases to 2 million m3,the flood capacity of the river will be greatly impacted and the scheme becomes invalid.The recommended scheme supported by the present study has been applied to the emergency river restoration after this mega-debris flow.  相似文献   

16.
（张本）（康星华）ＴＨＥＦＥＡＴＵＲＥＳＯＦＴＨＥＮＡＴＵＲＡＬＲＥＳＯＵＲＣＥＳＡＮＤＴＨＥＲＥＮＯＶＡＴＩＯＮＳＴＲＡＴＥＧＹＯＦＰＯＹＡＮＧＬＡＫＥ￥ＺｈａｎｇＢｅｎＫａｎｇＸｉｎｇｈｕａ（ＨａｉｎａｎＵｎｉｖｅｒｓｉｔｙ，Ｈａｉｋｏｕ５７００...  相似文献   

17.
Investigations from August, 1985 to July , 1986 showed that the high concentration area of PO4-P , SiO3-Si and NO3-N gradually reduced with the reduction of the area of the Changjiang River diluted water from summer, autumn to winter , and that the seasonal distributions and variations of the nutrients concentrations were mainly controlled by the river flow and were also related to the growth and decline of phytoplankton . The conservation of SiO3-Si and NO3-N in the estuary in the flood season was poorer than that in the dry season .. The behaviour of PO4-P in the estuary shows that aside from -biological removal, buffering of PCU-P is possible in the estuary . The highest monthly average concentrations and annual average concentrations in the river mouth were respectively 0.88 and 0.57 umol/L for PO4-P,191.5 and 96.2 umol/L for SiO3-Si, and 81.6 and 58.6 umol/L for NOs-N . The Changjiang's annual transports of PO4-P , SiO3-Si and NO3-N to the sea were about 1.4×104tons , 204.4×104 tons and 63.6×104  相似文献   

18.
Ｉ．ＩＮＴＲＯＤＵＣＴＩＯＮ“Ａｇｅｎｄａ２１”ｒｅｃｏｇｎｉｚｅｓｔｈｅｉｍｐｏｒｔａｎｃｅｏｆｌａｎｄｂａｓｅｄｓｏｕｒｃｅｐｏｌｕｔａｎｔｓｔｏｍａｒｉｎｅｐｏｌｕｔｉｏｎ．Ｃｏａｓｔａｌｗａｔｅｒｉｓｏｆｇｒｅａｔｓｉｇｎｉｆｉｃａｎｃｅ...  相似文献   

19.
The influence of land-based source pollutants to marine ecological environment is principally in coastal or enclosed sea wates. Flux of land-based source pollutants into the sea will be effected due to social and economic development in the Tumen River basin. Pollutant type and primary pollution factor of the Tumen River in Northeast China is described by weighted coefficient method in this paper. The results indicate that the river is organic pollution type and primary pollution factor is COD. Fresh water fraction proves that the estuary is not affected by tide cycle. COD annual flux entering the Sea of Japan calculated by zero-dimension model in 1993 was 90.50 × 103 tons. It is estimated with emission coefficient method that the COD will be 176.4 × 103 and 458.6 × 103 tons for the years of 2000 and 2010 respectively. This work is sponored by the Open Fund of State Key Laboratory on Environmental Aquatic Chemistry.  相似文献   

20.
The results of water sample analyses and investigation in the head area of the Changjiang River reveal that the characteristics of hydrochemistry of the river vary with drainage basins. In the drainage basin of the Tuotuo River, the mineral concentration of water is generally high, ions of Cl and Na are obviously dominant. The water tends to be salty, and the type of hydrochemistry is rather complex. In the drainage basin of the Dam River, the mineral concentration is mainly in a low and middle level, ions of HCO3- and Ca2 are higher than others, and the type of hydrochemistry is relatively simple. The ground water in deep layers plays an important role in recharging surface water, and the stable recharging results in little change in chemical composition of surface water.  相似文献   

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