Abstract： The Tigris and Euphrates Rivers are the main sources of water in Iraq. Iraq used to receive 33×109 m^3 of river water per year at Hit, 200 km downstream from the Syrian border before the 1970s. In 1980...Abstract： The Tigris and Euphrates Rivers are the main sources of water in Iraq. Iraq used to receive 33×109 m^3 of river water per year at Hit, 200 km downstream from the Syrian border before the 1970s. In 1980s, the discharge decreased to as little as 8 × 10^9 m^3 per year at Hit. The decreasing of discharge and water level in the Euphrates River causes problems of both quantity and quality, such as the increasing salinity in the internal delta downstream, the TDS （total dissolves salinity） at Hit has increased from less than 500 ppm to about 700 ppm. By 1989, the Euphrates＇ salinity at A1 Qaim reached 1,000 ppm. Currently, the TDS of the river, at AI Qaim, is greater than 1,000 ppm. The problem of control salinity has received considerable attention particularly when the surface water is extremely limited with poorly available ground water supply. The field measurement has achieved for TDS, pH （hydrogen ion）, EC （electric conductivity）, coliform content and heavy metal for three sectors in the Euphrates River basin in Iraq as well as the lakes of Tharthar, Habbaniya, and AI-Razzaza. The statistical analysis was made to relate these parameter with discharge and water level, which are refered to the important effect of the flow in river on the water quality of Euphrates River. The storage of water in the lakes Al-tharthar, Al-habbanya, and A1-Razzaza has a negative effects on the water quality, and shows that the best method for storage water is the reservoirs along river stream.展开更多
In developing countries, land productivity involves little market, where the agricultural land use is mainly determined by the food demands as well as the land suitability. The land use pattern will not ensure everywh...In developing countries, land productivity involves little market, where the agricultural land use is mainly determined by the food demands as well as the land suitability. The land use pattern will not ensure everywhere enough land for certain cropping if spatial allocation just according to land use suitability. To solve this problem, a subzone and a pre-allocation for each land use are added in spatial allocation module, and land use suitability and area optimi- zation module are incorporated to constitute a whole agricultural land use optimal allocation （ALUOA） system. The system is developed on the platform .Net 2005 using ArcGIS Engine （version 9.2） and C# language, and is tested and validated in Yili watershed of Xinjiang Region on the newly reclaimed area. In the case study, with the help of soil data obtained from 69 points sampled in the fieldwork in 2008, main river data supplied by the Department of Water Resources of Xinjiang Uygur Autonomous Region in China, and temperature data provided by Data Center for Resources and Environmental Sciences, Chinese Academy of Sciences, land use suitability on eight common crops are evaluated one by one using linear weighted summation method in the land use suitability model. The linear pro- gramming （LP） model in area optimization model succeeds to give out land area target of each crop under three scenarios. At last, the land use targets are allotted in space both with a six subzone file and without a subzone file. The resuits show that the land use maps with a subzone not only ensure every part has enough land for every crop, but also gives a more fragmental land use pattern, with about 87.99% and 135.92% more patches than the one without, while at the expense of loss between 15.30% and 19.53% in the overall suitability at the same time.展开更多
The oil-rich Damintun Depression is located in the Liaohe Basin, Northeast China, and was formed during the Paleogene. The major oil-producing strata in the depression are mudstone and shale. To explore the burial dia...The oil-rich Damintun Depression is located in the Liaohe Basin, Northeast China, and was formed during the Paleogene. The major oil-producing strata in the depression are mudstone and shale. To explore the burial diagenetic history of the basin and the formation thresholds of hydrocarbons, the characters of the kaolinite subgroup minerals and mixed-layer illite/smectite in the mudstone and the shale are studied by using X-ray diffraction, electron probe, scanning electron microscope, and Fourier infrared spectrum. The kaolinite subgroup consists of kaolinite and halloysite. The kaolinite is flake-like or vermiform-like. The halloysite is in long tubular shape and its length is related to its iron content. A longer tube has lower iron content. The crystallinity of kaolinite is 0.40 ~20, and its degree of order increases from 0.03 to 1.17 with the burial depth. Kaolinite is in disorder when the buried depth is less than or equal to 2479 m, and it is partially ordered when the buried depth is greater than 2479 m. Kaolinite is supposed to turn into dickite when the depth is greater than 2550 m, but low penetrability and low poros- ity of the shale and mudstone prevent such a change. The mixed-layer illite/smectite changes from disorder to order continually as the buried depth increases. Its disorder （RoI/S）, as defined by illite layer content （I%）, is smaller than 50% at depths less than 2550.25 m. Based on Hoffman ＆ Hower＇s model, the paleo-geothermal gradients of 3.37-3.76℃/100 m （3.57℃/100 m on average） can be derived in the Paleocene Damintun Depression, which is significantly higher than the present geothermal gradient （2.9℃00 m）. The threshold depth of the oil formation in the depression is about 2550 m.展开更多
Accurately identifying the spatial differences in the response of regional runoff to climate and land use changes can clarify the mechanism of regional runoff changes and provide a scientific basis for adopting the ap...Accurately identifying the spatial differences in the response of regional runoff to climate and land use changes can clarify the mechanism of regional runoff changes and provide a scientific basis for adopting the appropriate water resource protection policies.In this study,based on the Budyko theory,we quantitatively evaluated the spatial differences in the response of runoff to climate and land use changes in the Yiluo River Basin after 2000;calculated the sensitivity of runoff changes to precipitation(P),potential evapotranspiration(E_(0))and land use changes;and quantified the contributions of those three factors to runoff changes.The findings revealed that with decreasing elevation,precipitation gradually decreases,potential evapotranspiration gradually increases,and runoff gradually decreases in the Yiluo River basin.Influenced by the population density,both cultivated land and construction land are widely distributed with the middle and lower reaches of the basin,while the upper reaches are dominated by forest land.Compared with the base period(1985-1989),precipitation and potential evapotranspiration in the watershed during the change period(2000-2017)basically showed decreasing and increasing trends,respectively,with obvious spatial differentiation.P increased significantly in the upper reaches of the Yi River,with an average of 35.2 mm(-83.8-84.7 mm),while P increased and decreased in the other five subbasins,but the decreasing trend was more prominent.Among the subbasins,the upper and middle reaches of the Luo River showed the largest reductions in P,with an average of-34.2 mm(-145.9-20.6 mm),whereas the middle reaches of the Yi River showed the smallest reduction in P,with an average of-10.9 mm(-84.2-59.5 mm).The E_(0)in the different regions during the change period showed an increasing trend,and the increase in E_(0)gradually decreased from the upper reaches to the lower reaches.The E_(0)in the upper reaches of the Luo River showed the largest change,with an average of 45.3 mm(38.2-48.3 mm),while the lower reaches of the Yiluo River showed the smallest change,with an average of 7.3 mm(-3.2-17.1 mm).Land use changes were primarily from cultivated to construction land in the middle and lower reaches.Runoff changes were positively correlated with precipitation changes and negatively correlated with potential evapotranspiration and land use changes.The absolute values of the sensitivity coefficients of runoff to these environmental factors decreased with lower altitude,indicating a reduced responsiveness of the basin runoff under a warming and drying climate trend.Reductions in precipitation and changes in potential evapotranspiration have led to reductions in runoff ranging from 4.7 to 17.4 mm and from 0.7 to 9.1 mm,respectively,while land use changes led to corresponding runoff reductions of 23.0 to 46.5 mm,suggesting that land use changes are more likely to trigger runoff changes in the basin than climatic fluctuations.Given the dominance of cultivated land,especially in the middle and lower reaches,and the region’s high susceptibility to human activities,there has been a significant reduction in runoff in recent years.The contribution of land use change to the runoff reduction in the Yiluo River Basin was greater at lower elevations,up to 86.1%,while climatic effects were more significant at higher elevations,up to 27.8%.Therefore,promoting the implementation of projects such as water ecological restoration and returning farmland to forests are of great significance to curb the over-exploitation of groundwater,to formulate scientific management and scheduling policies in order to realize the transformation of the water balance in the river basin from a non-steady state to a steady state,and to promote the integrity of the ecosystem of the lower reaches of the Yellow River and ensure its sustainable development.展开更多
文摘Abstract： The Tigris and Euphrates Rivers are the main sources of water in Iraq. Iraq used to receive 33×109 m^3 of river water per year at Hit, 200 km downstream from the Syrian border before the 1970s. In 1980s, the discharge decreased to as little as 8 × 10^9 m^3 per year at Hit. The decreasing of discharge and water level in the Euphrates River causes problems of both quantity and quality, such as the increasing salinity in the internal delta downstream, the TDS （total dissolves salinity） at Hit has increased from less than 500 ppm to about 700 ppm. By 1989, the Euphrates＇ salinity at A1 Qaim reached 1,000 ppm. Currently, the TDS of the river, at AI Qaim, is greater than 1,000 ppm. The problem of control salinity has received considerable attention particularly when the surface water is extremely limited with poorly available ground water supply. The field measurement has achieved for TDS, pH （hydrogen ion）, EC （electric conductivity）, coliform content and heavy metal for three sectors in the Euphrates River basin in Iraq as well as the lakes of Tharthar, Habbaniya, and AI-Razzaza. The statistical analysis was made to relate these parameter with discharge and water level, which are refered to the important effect of the flow in river on the water quality of Euphrates River. The storage of water in the lakes Al-tharthar, Al-habbanya, and A1-Razzaza has a negative effects on the water quality, and shows that the best method for storage water is the reservoirs along river stream.
基金Under the auspices of National Natural Science Foundation of China (No. 41001108, 41071065)Beijing Municipal Natural Science Foundation (No. 9113029)
文摘In developing countries, land productivity involves little market, where the agricultural land use is mainly determined by the food demands as well as the land suitability. The land use pattern will not ensure everywhere enough land for certain cropping if spatial allocation just according to land use suitability. To solve this problem, a subzone and a pre-allocation for each land use are added in spatial allocation module, and land use suitability and area optimi- zation module are incorporated to constitute a whole agricultural land use optimal allocation （ALUOA） system. The system is developed on the platform .Net 2005 using ArcGIS Engine （version 9.2） and C# language, and is tested and validated in Yili watershed of Xinjiang Region on the newly reclaimed area. In the case study, with the help of soil data obtained from 69 points sampled in the fieldwork in 2008, main river data supplied by the Department of Water Resources of Xinjiang Uygur Autonomous Region in China, and temperature data provided by Data Center for Resources and Environmental Sciences, Chinese Academy of Sciences, land use suitability on eight common crops are evaluated one by one using linear weighted summation method in the land use suitability model. The linear pro- gramming （LP） model in area optimization model succeeds to give out land area target of each crop under three scenarios. At last, the land use targets are allotted in space both with a six subzone file and without a subzone file. The resuits show that the land use maps with a subzone not only ensure every part has enough land for every crop, but also gives a more fragmental land use pattern, with about 87.99% and 135.92% more patches than the one without, while at the expense of loss between 15.30% and 19.53% in the overall suitability at the same time.
基金supported by National Natural Science Foundation of China (Grant No. 40772027)
文摘The oil-rich Damintun Depression is located in the Liaohe Basin, Northeast China, and was formed during the Paleogene. The major oil-producing strata in the depression are mudstone and shale. To explore the burial diagenetic history of the basin and the formation thresholds of hydrocarbons, the characters of the kaolinite subgroup minerals and mixed-layer illite/smectite in the mudstone and the shale are studied by using X-ray diffraction, electron probe, scanning electron microscope, and Fourier infrared spectrum. The kaolinite subgroup consists of kaolinite and halloysite. The kaolinite is flake-like or vermiform-like. The halloysite is in long tubular shape and its length is related to its iron content. A longer tube has lower iron content. The crystallinity of kaolinite is 0.40 ~20, and its degree of order increases from 0.03 to 1.17 with the burial depth. Kaolinite is in disorder when the buried depth is less than or equal to 2479 m, and it is partially ordered when the buried depth is greater than 2479 m. Kaolinite is supposed to turn into dickite when the depth is greater than 2550 m, but low penetrability and low poros- ity of the shale and mudstone prevent such a change. The mixed-layer illite/smectite changes from disorder to order continually as the buried depth increases. Its disorder （RoI/S）, as defined by illite layer content （I%）, is smaller than 50% at depths less than 2550.25 m. Based on Hoffman ＆ Hower＇s model, the paleo-geothermal gradients of 3.37-3.76℃/100 m （3.57℃/100 m on average） can be derived in the Paleocene Damintun Depression, which is significantly higher than the present geothermal gradient （2.9℃00 m）. The threshold depth of the oil formation in the depression is about 2550 m.
基金The National Natural Science Foundation of China(52130907)。
文摘Accurately identifying the spatial differences in the response of regional runoff to climate and land use changes can clarify the mechanism of regional runoff changes and provide a scientific basis for adopting the appropriate water resource protection policies.In this study,based on the Budyko theory,we quantitatively evaluated the spatial differences in the response of runoff to climate and land use changes in the Yiluo River Basin after 2000;calculated the sensitivity of runoff changes to precipitation(P),potential evapotranspiration(E_(0))and land use changes;and quantified the contributions of those three factors to runoff changes.The findings revealed that with decreasing elevation,precipitation gradually decreases,potential evapotranspiration gradually increases,and runoff gradually decreases in the Yiluo River basin.Influenced by the population density,both cultivated land and construction land are widely distributed with the middle and lower reaches of the basin,while the upper reaches are dominated by forest land.Compared with the base period(1985-1989),precipitation and potential evapotranspiration in the watershed during the change period(2000-2017)basically showed decreasing and increasing trends,respectively,with obvious spatial differentiation.P increased significantly in the upper reaches of the Yi River,with an average of 35.2 mm(-83.8-84.7 mm),while P increased and decreased in the other five subbasins,but the decreasing trend was more prominent.Among the subbasins,the upper and middle reaches of the Luo River showed the largest reductions in P,with an average of-34.2 mm(-145.9-20.6 mm),whereas the middle reaches of the Yi River showed the smallest reduction in P,with an average of-10.9 mm(-84.2-59.5 mm).The E_(0)in the different regions during the change period showed an increasing trend,and the increase in E_(0)gradually decreased from the upper reaches to the lower reaches.The E_(0)in the upper reaches of the Luo River showed the largest change,with an average of 45.3 mm(38.2-48.3 mm),while the lower reaches of the Yiluo River showed the smallest change,with an average of 7.3 mm(-3.2-17.1 mm).Land use changes were primarily from cultivated to construction land in the middle and lower reaches.Runoff changes were positively correlated with precipitation changes and negatively correlated with potential evapotranspiration and land use changes.The absolute values of the sensitivity coefficients of runoff to these environmental factors decreased with lower altitude,indicating a reduced responsiveness of the basin runoff under a warming and drying climate trend.Reductions in precipitation and changes in potential evapotranspiration have led to reductions in runoff ranging from 4.7 to 17.4 mm and from 0.7 to 9.1 mm,respectively,while land use changes led to corresponding runoff reductions of 23.0 to 46.5 mm,suggesting that land use changes are more likely to trigger runoff changes in the basin than climatic fluctuations.Given the dominance of cultivated land,especially in the middle and lower reaches,and the region’s high susceptibility to human activities,there has been a significant reduction in runoff in recent years.The contribution of land use change to the runoff reduction in the Yiluo River Basin was greater at lower elevations,up to 86.1%,while climatic effects were more significant at higher elevations,up to 27.8%.Therefore,promoting the implementation of projects such as water ecological restoration and returning farmland to forests are of great significance to curb the over-exploitation of groundwater,to formulate scientific management and scheduling policies in order to realize the transformation of the water balance in the river basin from a non-steady state to a steady state,and to promote the integrity of the ecosystem of the lower reaches of the Yellow River and ensure its sustainable development.
