[Objective] This study was to provide basis for the scientific management of land use in Haihe River Basin (HRB) through the quantitative exploration of the land use conversion, changes of intensity and spatial dist...[Objective] This study was to provide basis for the scientific management of land use in Haihe River Basin (HRB) through the quantitative exploration of the land use conversion, changes of intensity and spatial distribution in this region. [Method] With the support of remote sensing technology and geographic information technology, the land use maps of the study area in 40 years (1970-2010) were in- terpreted and plotted. Four kinds of tupu, namely, land use change tupu, process tupu, arising tupu and evolution mode tupu were built through the spatial overlay of the land use maps to analyze the change rules of land use patterns. [Result] The conversion of arable land to construction land was the main characteristics of land use changes in HRB for the 40 years; the area of non-stable region accounted for 35% of the total, indicating that the land use changed remarkably, thus, it was nec- essary to strengthen the scientific land management in HRB; the new conversions to all land use patterns were all the lowest in 1980-1990, indicating that land use changed slowly during this period. [Conclusion] The results indicate that, compared with conventional transfer matrix method, geo-information tupu has obvious advantage in analyzing land use changes that it can demonstrate the spatial distribution of interest region, display the multi-dimensional spatial information.展开更多
Selecting six indexs of pH, DO, COD, BOD5, ammonia nitrogen and petroleum hydrocarbons in Haihe River Basin of four seasons in 2012 - 2013 for factor analysis, appling Water Quality Pollution Index (API) to evaluate...Selecting six indexs of pH, DO, COD, BOD5, ammonia nitrogen and petroleum hydrocarbons in Haihe River Basin of four seasons in 2012 - 2013 for factor analysis, appling Water Quality Pollution Index (API) to evaluate DO, COD, BOD5 and ammonia nitrogen, aims for systematic evluation to water quality of Haihe River Basin The results showed that two stations of B J1 and HB2 were the 1V type of water, others were the V type; Water Quality Pollution Index (API) was 1.44, which illustrated Haihe River Basin in the state of contamination that the degree of pollution exceeded the standard of functional areas. Factor Analysis explained that between COD, DO and NH3-N were significant difference (P〈0.05); principal component analysis showed that, in addition to pH and BOD5, the other indicators were above 0.70; the contribution rate of COD, DO, NH3-N and TPH were higher, petroleum hydrocarbons was 100%, it can be considered that the waters type of pollution was organic pollution, and petroleum hydrocarbon contamination was more prominent.展开更多
The Huolin River is one of the most important water sources for Xianghai wetland, Horqin wetland, and Chaganhu wetland in the western Songnen Plain of Northeast China. The annual runoff series of 46 years at Baiyunhus...The Huolin River is one of the most important water sources for Xianghai wetland, Horqin wetland, and Chaganhu wetland in the western Songnen Plain of Northeast China. The annual runoff series of 46 years at Baiyunhushuo Hydrologic Station, which is located in the middle reaches of the Huolin River, were analyzed by using wavelet analysis. Main objective was to discuss the periodic characteristics of the runoff, and examine the temporal patterns of the Huolin River recharging to the floodplain wetlands in the lower reaches of the river, and the corresponding effects of recharging variation on the environmental evolution of the wetlands. The results show that the annual runoff varied mainly at three time scales. The intensities of periodical signals at different time scales were strongly characterized by local distribution in its time frequency domain. The interdecadal variation at a scale of more than 30yr played a leading role in the temporal pattern ofrnnoffvariation, and at this scale, the runoffat Baiyunhushuo Hydrologic Station varied in turn of flood, draught and flood. Accordingly, the landscape of the floodplain wetlands presented periodic features, especially prominent before the 1990s. Compared with intense human activities, the runoff periodic pattern at middle (10-20yr) and small (1-10yr) scales, which has relatively low energy, exerted unobvious effects on the environmental evolution of the floodplain wetlands, especially after the 1990s.展开更多
Although the quantification and valuation of ecosystem services have been studied for a long time, few studies have specifi- cally focused on the quantification of tradeoffs between ecosystem services and tradeoff hot...Although the quantification and valuation of ecosystem services have been studied for a long time, few studies have specifi- cally focused on the quantification of tradeoffs between ecosystem services and tradeoff hotspots, Based on previous studies of ecosys- tem service assessment, we proposed a feasible method to analyze the tradeoffs between ecosystem services, including determination of their relationship, quantification of tradeoffs, and identification of tradeoff hotspots. Potential influencing factors were then further ana- lyzed. The Yanhe Basin in the Loess Plateau was selected as an example to demonstrate the application process. Firstly, the amounts of net primary production (NPP) and water yield (WY) in 2000 and 2008 were estimated by using biophysical models, Secondly, correla- tion analysis was used to indicate the tradeoffs between NPP and WY. Thirdly, tradeoff index (TINpp/wy) was established to quantify the extent of tradeoffs between NPP and WY, and the average value of TINpp/wy is 24.4 g/(mm·m2) for the Yanhe Basin between 2000 and 2008. Finally, the tradeoff hotspots were identified. The results indicated that the area of lowest tradeoff index concentrated in the mid- dle part of the Yanhe Basin and marginal areas of the southern basin. Map overlapping was used for preliminary analysis to seek poten- tial influencing factors, and the results showed that shrub was the best suited for growing in the Yanhe Basin, but also was a potential irtfluencing factor for formulatiort of the tradeoff hotspots. The concept of tradeoff index could also be used to quantify the degree of synergy between different ecosystem services. The method to identify the tradeoff hotspots could help us to narrow the scope of study area for further research on the relationship among ecosystem services and concentrate on the potential factors for formation of tradeoff between ecosystem services, enhance the capacity to maintain the sustainability of ecosystem.展开更多
Based on monthly river runoff and meteorological data, a method of Morlet wavelet transform was used to analyze the multiple time scale characteristics of river runoff in the Dagujia River Basin, Yantai City, Shandong...Based on monthly river runoff and meteorological data, a method of Morlet wavelet transform was used to analyze the multiple time scale characteristics of river runoff in the Dagujia River Basin, Yantai City, Shandong Province. The results showed that the total annual river runoffin the Dagujia River Basin decreased significantly from 1966 to 2004, and the rate of decrease was 48× 10^6ma/10yr, which was higher than the mean value of most rivers in China. Multiple time scale characteristics existed, which accounted for different aspects of the changes in annual river runoff, and the major periods of the runofftime series were identified as about 28 years, 14 years and 4 years with decreasing levels of fluctuation. The river runoff evolution process was controlled by changes in precipitation to a certain extent, but it was also greatly influenced by human activities. Also, for different time periods and scales, the impacts of climate changes and human activities on annual river runoff evolution occurred at the same time. Changes in the annual river runoffwere mainly associated with climate change before the 1980s and with human activities after 1981.展开更多
Resulting from the collision of the Eurasian and Indian plates, the Qinghai-Tibetan Plateau is commonly known as the 'roof of the world'. Collectively the Yarlung Tsangpo, Nu, Laneang, Yangtze, Yalong, and Yellow Ri...Resulting from the collision of the Eurasian and Indian plates, the Qinghai-Tibetan Plateau is commonly known as the 'roof of the world'. Collectively the Yarlung Tsangpo, Nu, Laneang, Yangtze, Yalong, and Yellow River basins drain the eastern margin of the plateau. In this paper, we utilize Shuttle Radar Topography Mission elevation data to examine morphometric and relief attributes of these basins to reveal insights rates of incision. A robust into tectonic activity and technique using Maflab is proposed to alleviate errors associated with SRTM data in the derivation of river longitudinal profiles. Convex longitudinal profiles are interpreted to be a product of uplift rates that exceed rates of channel incision along the entire margin of the Qinghai- Tibetan Plateau. Highest relief towards the south reflects extensive fluvial incision. High relief is also prominent along major active faults. Erosion patterns are related to distance from knickpoints. Highest rates of erosion and incision are evident towards the south, with decreasing values towards the north, suggesting a link between tectonic activity and erosion.展开更多
Over the last several decades,various sediment transport capacity formulations have been used by geomorphologists and engineers to calculate fluvial morphological changes.However,it remains poorly understood if the ad...Over the last several decades,various sediment transport capacity formulations have been used by geomorphologists and engineers to calculate fluvial morphological changes.However,it remains poorly understood if the adaptation to capacity could be fulfilled instantly in response to differing inflow discharges and sediment supplies,and thus if the calculation of morphological changes in rivers based on the assumed capacity status is fully justified.Here we present a numerical investigation on this issue.The distance required for sediment transport to adapt to capacity(i.e.,adaptation-to-capacity length) of both bed load and suspended sediment transport is computationally studied using a coupled shallow water hydrodynamic model,in line with varied inlet sediment concentrations.It is found that the adaptation-to-capacity length generally decreases as the Rouse number increases,irrespective of whether the inlet sediment concentration increases or reduces.For cases with vanishing inlet sediment concentration a unified relationship is found between the adaptation-to-capacity length and the Rouse number.Quantitatively,the adaptation-to-capacity length of bed load sediment is limited to tens of times of the flow depth,whilst that of suspended sediment increases substantially with decreasing Rouse number and can be up to hundreds of times of the flow depth.The present finding concurs that bed load sediment transport can adapt to capacity much more rapidly than suspended sediment transport,and it facilitates a quantitative criterion on which the applicability of bed load or suspended sediment transport capacity for natural rivers can be readily assessed.展开更多
To evaluate the long-term environmental effect of the nitrobenzene precipitated into Songhua River caused by the explosion accident of CNPC Jilin Petrochemical Company, we have proved that three selected cross section...To evaluate the long-term environmental effect of the nitrobenzene precipitated into Songhua River caused by the explosion accident of CNPC Jilin Petrochemical Company, we have proved that three selected cross sections were all in a completely mixed state which was not affected by the neighborhood flow firstly. The research of the main flux of contaminants indicates that the nitrobenzene flux in all cross sections is less and less, and the attenuation trend is gradually slowing down. From the residual remnant of nitrobenzene in different segments calculated according to the related experimental data, we suppose that parts of nitrobenzene remnant are transferred by the bottom sludge adsorption and resolution. A general analysis model was set up from the one-dimensional counter-flow equation, and functions of atmosphere-water exchange process, deposit-water interaction, and river turbulent mixing and dissemination. The results of this quantification analysis are different from the real calculation, while the gross transformation trend is the same, which indicates that both analyses are based on reality and can reflect the transport and transformation of nitrobenzene actually.展开更多
In the present scenario,tapping the unutilised hydropower potential is one of the highest priorities in developing countries of the world.Special emphasis is being imparted to run of the river(RoR)mode of power genera...In the present scenario,tapping the unutilised hydropower potential is one of the highest priorities in developing countries of the world.Special emphasis is being imparted to run of the river(RoR)mode of power generation.However,the governments are now facing the dilemma whether to promote small hydropower projects(SHPs) or encourage large hydropower projects(LHPs).RoR large hydropower projects result into large scale cutting of mountains for constructing tunnels and access roads,generation of huge quantity of muck and large scale impact on flora and fauna due to diversion of rivers/streams.On the other hand,though SHPs are claimed to be greener and more sustainable by a section of researchers and energy planners but,they will be required to be set up in large number to generate equivalent amount of electricity.The aim of this study is to rank the most sustainable installed capacity range of RoR hydropower projects.To achieve this aim,the study proposes the use of quite popular multi-criteria decision making(MCDM)method of Operation Research named Analytical Hierarchy Process.A case study has been presented from Himachal Pradesh,a hydro rich state located in the western Himalayan region.As per sustainability assessment carried out in this study,hydropower projects in the capacity range 1 to 5 MW have been ranked to be the most sustainable.展开更多
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 qu...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.展开更多
The arid zone rivers Amudarya and Syrdarya are located in Central Asia and are subjected to the influx of different kinds of natural and anthropogenic pollutants. The concentrations and speciation of heavy metals, nam...The arid zone rivers Amudarya and Syrdarya are located in Central Asia and are subjected to the influx of different kinds of natural and anthropogenic pollutants. The concentrations and speciation of heavy metals, namely, Hg, Cr, Cd, Co, U, Zn, Sc, Fe, Br, Au, and Sm. in the Amudarya and Syrdarya rivers water in the territory of Uzbekistan were investigated by applying the neutron-activation analysis and through experimental modeling using appropriate radionuclides. The heavy metals speciation in the rivers water was separated in cationic, anionic, and a combination of colloidal and neutral forms. The experimental results showed that heavy metals in the Amudarya and Syrdarya rivers water migrate as a complex set of suspended solids, cationic, anionic, and a combination of colloidal neutral forms. The ratio of neutral and colloidal forms averages approximately 40% for the majority of the investigated heavy metals, and the share of neutral and colloidal forms of heavy metals in the Syrdarya river water is slightly less than in the Amudarya river water (10-20%), which might be due to discharge of water from agricultural and industry sectors into the river.展开更多
Based on the comparison between several model outputs from CMIP5 (Coupled Model Intercomparison Project Phase-5) and the satellite rainfall mapping data of GSMaP (global satellite mapping of precipitation), This p...Based on the comparison between several model outputs from CMIP5 (Coupled Model Intercomparison Project Phase-5) and the satellite rainfall mapping data of GSMaP (global satellite mapping of precipitation), This paper selected MIROC4h as a future projection of rainfall in the Sittaung River basin, Myanmar, with the fine spatial resolution of 0.5°. At first, MIROC4h projection towards 2035 was corrected by using the error trend (GSMaP-MIROC4h) for nine years over-rapping of both outputs from 2006 to 2014. Assuming the seasonal autoregressive processes, future error trend at each grid point was estimated by the time series forecast of SARMAP processes using the nine years training data. Then future projection correction was done by M1ROC4h output plus error trend at each grid point to obtain the corrected MIROC4h precipitation. As a historical analysis, using the corrected precipitation in the Sittaung River basin and observed river discharge at the outlet of the river, the hydrological model (HSPF (Hydrological Simulation Program Fortran)) calibration was carried out with consideration of the water utilization data for darn/reservoir and irrigation. As a projection analysis, future simulation of hourly discharge at the outlet of Sittaung River from 2015 to 2035 was conducted by using the corrected MIROC4h precipitation. The results of projection analysis show that high risks of flood will appear in 2023 and 2028 and the risks of draught will be expected in 2019-2021.展开更多
基金Supported by the Key Technology R&D Program of Hebei Province (10277105D)the Funds of the Chinese Academy of Sciences for Key Topics in Innovation Engineering(KSCX-EW-J-5)~~
文摘[Objective] This study was to provide basis for the scientific management of land use in Haihe River Basin (HRB) through the quantitative exploration of the land use conversion, changes of intensity and spatial distribution in this region. [Method] With the support of remote sensing technology and geographic information technology, the land use maps of the study area in 40 years (1970-2010) were in- terpreted and plotted. Four kinds of tupu, namely, land use change tupu, process tupu, arising tupu and evolution mode tupu were built through the spatial overlay of the land use maps to analyze the change rules of land use patterns. [Result] The conversion of arable land to construction land was the main characteristics of land use changes in HRB for the 40 years; the area of non-stable region accounted for 35% of the total, indicating that the land use changed remarkably, thus, it was nec- essary to strengthen the scientific land management in HRB; the new conversions to all land use patterns were all the lowest in 1980-1990, indicating that land use changed slowly during this period. [Conclusion] The results indicate that, compared with conventional transfer matrix method, geo-information tupu has obvious advantage in analyzing land use changes that it can demonstrate the spatial distribution of interest region, display the multi-dimensional spatial information.
基金supported by the Key Laboratory of Marine Oil Spill Identification and Damage Assessment Technology, State Oceanic Administration (201214)
文摘Selecting six indexs of pH, DO, COD, BOD5, ammonia nitrogen and petroleum hydrocarbons in Haihe River Basin of four seasons in 2012 - 2013 for factor analysis, appling Water Quality Pollution Index (API) to evaluate DO, COD, BOD5 and ammonia nitrogen, aims for systematic evluation to water quality of Haihe River Basin The results showed that two stations of B J1 and HB2 were the 1V type of water, others were the V type; Water Quality Pollution Index (API) was 1.44, which illustrated Haihe River Basin in the state of contamination that the degree of pollution exceeded the standard of functional areas. Factor Analysis explained that between COD, DO and NH3-N were significant difference (P〈0.05); principal component analysis showed that, in addition to pH and BOD5, the other indicators were above 0.70; the contribution rate of COD, DO, NH3-N and TPH were higher, petroleum hydrocarbons was 100%, it can be considered that the waters type of pollution was organic pollution, and petroleum hydrocarbon contamination was more prominent.
基金Under the auspices of Knowledge Innovation Program of Chinese Academy of Sciences (No. KZCX3-SW-332-01)
文摘The Huolin River is one of the most important water sources for Xianghai wetland, Horqin wetland, and Chaganhu wetland in the western Songnen Plain of Northeast China. The annual runoff series of 46 years at Baiyunhushuo Hydrologic Station, which is located in the middle reaches of the Huolin River, were analyzed by using wavelet analysis. Main objective was to discuss the periodic characteristics of the runoff, and examine the temporal patterns of the Huolin River recharging to the floodplain wetlands in the lower reaches of the river, and the corresponding effects of recharging variation on the environmental evolution of the wetlands. The results show that the annual runoff varied mainly at three time scales. The intensities of periodical signals at different time scales were strongly characterized by local distribution in its time frequency domain. The interdecadal variation at a scale of more than 30yr played a leading role in the temporal pattern ofrnnoffvariation, and at this scale, the runoffat Baiyunhushuo Hydrologic Station varied in turn of flood, draught and flood. Accordingly, the landscape of the floodplain wetlands presented periodic features, especially prominent before the 1990s. Compared with intense human activities, the runoff periodic pattern at middle (10-20yr) and small (1-10yr) scales, which has relatively low energy, exerted unobvious effects on the environmental evolution of the floodplain wetlands, especially after the 1990s.
基金Under the auspices of National Natural Sciences Foundation of China(No.41230745)Major Program of High Resolution Earth Observation System(No.30-Y30B13-9003-14/16-02)
文摘Although the quantification and valuation of ecosystem services have been studied for a long time, few studies have specifi- cally focused on the quantification of tradeoffs between ecosystem services and tradeoff hotspots, Based on previous studies of ecosys- tem service assessment, we proposed a feasible method to analyze the tradeoffs between ecosystem services, including determination of their relationship, quantification of tradeoffs, and identification of tradeoff hotspots. Potential influencing factors were then further ana- lyzed. The Yanhe Basin in the Loess Plateau was selected as an example to demonstrate the application process. Firstly, the amounts of net primary production (NPP) and water yield (WY) in 2000 and 2008 were estimated by using biophysical models, Secondly, correla- tion analysis was used to indicate the tradeoffs between NPP and WY. Thirdly, tradeoff index (TINpp/wy) was established to quantify the extent of tradeoffs between NPP and WY, and the average value of TINpp/wy is 24.4 g/(mm·m2) for the Yanhe Basin between 2000 and 2008. Finally, the tradeoff hotspots were identified. The results indicated that the area of lowest tradeoff index concentrated in the mid- dle part of the Yanhe Basin and marginal areas of the southern basin. Map overlapping was used for preliminary analysis to seek poten- tial influencing factors, and the results showed that shrub was the best suited for growing in the Yanhe Basin, but also was a potential irtfluencing factor for formulatiort of the tradeoff hotspots. The concept of tradeoff index could also be used to quantify the degree of synergy between different ecosystem services. The method to identify the tradeoff hotspots could help us to narrow the scope of study area for further research on the relationship among ecosystem services and concentrate on the potential factors for formation of tradeoff between ecosystem services, enhance the capacity to maintain the sustainability of ecosystem.
基金Under the auspices of National Key Science and Technology Support Program of China (No. 2006BCA01A07-2)National Natural Science Foundation of China (No. 40101005)Science Foundation of Shandong Province, China (No. Q02E03)
文摘Based on monthly river runoff and meteorological data, a method of Morlet wavelet transform was used to analyze the multiple time scale characteristics of river runoff in the Dagujia River Basin, Yantai City, Shandong Province. The results showed that the total annual river runoffin the Dagujia River Basin decreased significantly from 1966 to 2004, and the rate of decrease was 48× 10^6ma/10yr, which was higher than the mean value of most rivers in China. Multiple time scale characteristics existed, which accounted for different aspects of the changes in annual river runoff, and the major periods of the runofftime series were identified as about 28 years, 14 years and 4 years with decreasing levels of fluctuation. The river runoff evolution process was controlled by changes in precipitation to a certain extent, but it was also greatly influenced by human activities. Also, for different time periods and scales, the impacts of climate changes and human activities on annual river runoff evolution occurred at the same time. Changes in the annual river runoffwere mainly associated with climate change before the 1980s and with human activities after 1981.
基金Funding was provided by International Science&Technology Cooperation Program of China(Grant Nos.2011DFG93160,2011DFA20820)
文摘Resulting from the collision of the Eurasian and Indian plates, the Qinghai-Tibetan Plateau is commonly known as the 'roof of the world'. Collectively the Yarlung Tsangpo, Nu, Laneang, Yangtze, Yalong, and Yellow River basins drain the eastern margin of the plateau. In this paper, we utilize Shuttle Radar Topography Mission elevation data to examine morphometric and relief attributes of these basins to reveal insights rates of incision. A robust into tectonic activity and technique using Maflab is proposed to alleviate errors associated with SRTM data in the derivation of river longitudinal profiles. Convex longitudinal profiles are interpreted to be a product of uplift rates that exceed rates of channel incision along the entire margin of the Qinghai- Tibetan Plateau. Highest relief towards the south reflects extensive fluvial incision. High relief is also prominent along major active faults. Erosion patterns are related to distance from knickpoints. Highest rates of erosion and incision are evident towards the south, with decreasing values towards the north, suggesting a link between tectonic activity and erosion.
基金funded by Natural Science Foundation of China (Grants Nos. 11172217, 10932012 and 10972164)
文摘Over the last several decades,various sediment transport capacity formulations have been used by geomorphologists and engineers to calculate fluvial morphological changes.However,it remains poorly understood if the adaptation to capacity could be fulfilled instantly in response to differing inflow discharges and sediment supplies,and thus if the calculation of morphological changes in rivers based on the assumed capacity status is fully justified.Here we present a numerical investigation on this issue.The distance required for sediment transport to adapt to capacity(i.e.,adaptation-to-capacity length) of both bed load and suspended sediment transport is computationally studied using a coupled shallow water hydrodynamic model,in line with varied inlet sediment concentrations.It is found that the adaptation-to-capacity length generally decreases as the Rouse number increases,irrespective of whether the inlet sediment concentration increases or reduces.For cases with vanishing inlet sediment concentration a unified relationship is found between the adaptation-to-capacity length and the Rouse number.Quantitatively,the adaptation-to-capacity length of bed load sediment is limited to tens of times of the flow depth,whilst that of suspended sediment increases substantially with decreasing Rouse number and can be up to hundreds of times of the flow depth.The present finding concurs that bed load sediment transport can adapt to capacity much more rapidly than suspended sediment transport,and it facilitates a quantitative criterion on which the applicability of bed load or suspended sediment transport capacity for natural rivers can be readily assessed.
基金the National Basic Research Program of China(973 Program) (Grant No.2004CB4185).
文摘To evaluate the long-term environmental effect of the nitrobenzene precipitated into Songhua River caused by the explosion accident of CNPC Jilin Petrochemical Company, we have proved that three selected cross sections were all in a completely mixed state which was not affected by the neighborhood flow firstly. The research of the main flux of contaminants indicates that the nitrobenzene flux in all cross sections is less and less, and the attenuation trend is gradually slowing down. From the residual remnant of nitrobenzene in different segments calculated according to the related experimental data, we suppose that parts of nitrobenzene remnant are transferred by the bottom sludge adsorption and resolution. A general analysis model was set up from the one-dimensional counter-flow equation, and functions of atmosphere-water exchange process, deposit-water interaction, and river turbulent mixing and dissemination. The results of this quantification analysis are different from the real calculation, while the gross transformation trend is the same, which indicates that both analyses are based on reality and can reflect the transport and transformation of nitrobenzene actually.
文摘In the present scenario,tapping the unutilised hydropower potential is one of the highest priorities in developing countries of the world.Special emphasis is being imparted to run of the river(RoR)mode of power generation.However,the governments are now facing the dilemma whether to promote small hydropower projects(SHPs) or encourage large hydropower projects(LHPs).RoR large hydropower projects result into large scale cutting of mountains for constructing tunnels and access roads,generation of huge quantity of muck and large scale impact on flora and fauna due to diversion of rivers/streams.On the other hand,though SHPs are claimed to be greener and more sustainable by a section of researchers and energy planners but,they will be required to be set up in large number to generate equivalent amount of electricity.The aim of this study is to rank the most sustainable installed capacity range of RoR hydropower projects.To achieve this aim,the study proposes the use of quite popular multi-criteria decision making(MCDM)method of Operation Research named Analytical Hierarchy Process.A case study has been presented from Himachal Pradesh,a hydro rich state located in the western Himalayan region.As per sustainability assessment carried out in this study,hydropower projects in the capacity range 1 to 5 MW have been ranked to be the most sustainable.
基金supported by the National Basic Research Program of China ("973" Project) (Grant No. 2011CB409903)the National Natural Science Foundation of China (Grant No. 50739002)
文摘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.
文摘The arid zone rivers Amudarya and Syrdarya are located in Central Asia and are subjected to the influx of different kinds of natural and anthropogenic pollutants. The concentrations and speciation of heavy metals, namely, Hg, Cr, Cd, Co, U, Zn, Sc, Fe, Br, Au, and Sm. in the Amudarya and Syrdarya rivers water in the territory of Uzbekistan were investigated by applying the neutron-activation analysis and through experimental modeling using appropriate radionuclides. The heavy metals speciation in the rivers water was separated in cationic, anionic, and a combination of colloidal and neutral forms. The experimental results showed that heavy metals in the Amudarya and Syrdarya rivers water migrate as a complex set of suspended solids, cationic, anionic, and a combination of colloidal neutral forms. The ratio of neutral and colloidal forms averages approximately 40% for the majority of the investigated heavy metals, and the share of neutral and colloidal forms of heavy metals in the Syrdarya river water is slightly less than in the Amudarya river water (10-20%), which might be due to discharge of water from agricultural and industry sectors into the river.
文摘Based on the comparison between several model outputs from CMIP5 (Coupled Model Intercomparison Project Phase-5) and the satellite rainfall mapping data of GSMaP (global satellite mapping of precipitation), This paper selected MIROC4h as a future projection of rainfall in the Sittaung River basin, Myanmar, with the fine spatial resolution of 0.5°. At first, MIROC4h projection towards 2035 was corrected by using the error trend (GSMaP-MIROC4h) for nine years over-rapping of both outputs from 2006 to 2014. Assuming the seasonal autoregressive processes, future error trend at each grid point was estimated by the time series forecast of SARMAP processes using the nine years training data. Then future projection correction was done by M1ROC4h output plus error trend at each grid point to obtain the corrected MIROC4h precipitation. As a historical analysis, using the corrected precipitation in the Sittaung River basin and observed river discharge at the outlet of the river, the hydrological model (HSPF (Hydrological Simulation Program Fortran)) calibration was carried out with consideration of the water utilization data for darn/reservoir and irrigation. As a projection analysis, future simulation of hourly discharge at the outlet of Sittaung River from 2015 to 2035 was conducted by using the corrected MIROC4h precipitation. The results of projection analysis show that high risks of flood will appear in 2023 and 2028 and the risks of draught will be expected in 2019-2021.