Stormwater runoff in rural townships has a high potential for water quality impairment but little information is available on strormwater runoff pollution from rural townships.To investigate the characteristics of run...Stormwater runoff in rural townships has a high potential for water quality impairment but little information is available on strormwater runoff pollution from rural townships.To investigate the characteristics of runoff pollution in a rural township,a catchment(2.32 ha) in Linshan Township,Sichuan,China was selected to examine runoff and quality parameters including precipitation,flow rate,and total nitrogen(TN),dissolved nitrogen(DN),total phosphorus(TP),dissolved phosphorus(DP),particulate phosphorus(PP),chemical oxygen demand(COD) and suspended solid(SS) in 12 rainfall events occurring between June 2006 and July 2007.Results show that the annual pollutant loads were 47.17 kg ha-1 for TN,6.64 kg ha-1 for TP,1186 kg ha-1 for COD,and 4297 kg ha-1 for SS.DN and PP were the main forms of nitrogen and phosphorus in stormwater runoff.TP,COD and SS showed medium mass first flushes,in which nearly 40% of the total pollutant masses were transported by the first 30% of total flow volume.The peak of pollutant concentration appeared before the peak of runoff due to the first flush of accumulative pollutants in impervious areas and drainage ditches.The EMC values of TN,TP,DN and PP were negatively correlated to the maximum rainfall intensity,precipitation,total flow volume,and runoff duration(P<0.05,n=12),while EMC of COD and SS were not related to any rainfall characteristics.The FF30(FF,First Flush) for TN,TP,COD and SS were positively correlated to the maximum rainfall intensity(P<0.05,n=12),and TP was also positively correlated to the average rainfall intensity(P<0.05,n=12),indicating that the magnitude of first flush increased with the rainfall intensity in the Linshan Township.展开更多
Hydrological and hydro-chemical monitoring of nitrogen(N) and phosphorus(P) in a small urbanized catchment was conducted in the hilly area of the central Sichuan Basin,China,from 2010 through 2011.The diffuse N and P ...Hydrological and hydro-chemical monitoring of nitrogen(N) and phosphorus(P) in a small urbanized catchment was conducted in the hilly area of the central Sichuan Basin,China,from 2010 through 2011.The diffuse N and P loadings in different forms of total nitrogen(TN) and phosphorus(TP),dissolved nitrogen(DN) and phosphorus(DP),as well as particulate nitrogen(PN) and phosphorus(PP) were calculated based on runoff discharges and chemical analyses.The results revealed that the diffuse pollution concentrations of TN,DN,PN,TP,DP and PP exhibited large variations during rainfall events,with peak concentrations occurring during the initial period.For all of the measured parameters,the event mean concentrations(EMCs) were observed to clearly vary among rainfall events.The EMCs of TN,DN,PN,TP,DP and PP(for all of the observed rainfall events) were 10.04,6.62,3.42,1.30,0.47 and0.83 mg/L,respectively.The losses of diffuse N and P exhibited clear seasonal patterns and mainly occurred during the period from July through September,when the losses totaled 99.3 and 9.6 kg/ha for TN and TP,respectively,accounting for 75% and 74% of the total annual loadings.The mean annual loadings of TN and TP were 124.6 and 12.9 kg/ha,respectively.The results indicate that residential areas in the hilly areaof the central Sichuan Basin are subject to high diffuse N and P loadings,posing a serious risk to the receiving water quality.Ecological buffering belts are recommended to incorporate into the urbanized catchment to reduce diffuse pollution.展开更多
Investigation of phosphorus (P) sorption-desorption characteristics of drainage ditch sediments is important for better understanding on sediment P transport behaviors in ditches. Surface ditch sediment samples were c...Investigation of phosphorus (P) sorption-desorption characteristics of drainage ditch sediments is important for better understanding on sediment P transport behaviors in ditches. Surface ditch sediment samples were collected from headwater sub-catchment of forestland, sloping cropland, paddy field, and residential area in a representative catchment in the central Sichuan Basin. These sediment samples were used for determination of P sorption-desorption characteristics by a batch equilibrium technique. Results showed that the maximum P sorption capacities (Qm) in the sediments ranged from 159.7 to 263.7 mg/kg, while higher Qm were observed in the ditch sediments from the paddy fields. The Qm was significantly and positively correlated with oxalate-extractable Fe and Al oxides (r=0.97 and 0.98, p < 0.01), clay fraction (r = 0.78, p < 0.05) and organic matter (r = 0.95, p < 0.01). Sediment pH, clay and organic matter influenced the P sorption through amorphous Fe and Al oxides. CaCO3 content was negatively correlated with the Qm (r = -0.83, p < 0.05), implying that saturated CaCO3 (> 50 g/kg) would not increase P sorption capacity in the ditch sediments. The ditch sediments featured a linear desorption curve, suggesting that P release risk would be enhanced with the increase of the P adsorption. The P desorption rate was positively correlated with Olsen P (r = 0.94, p < 0.01), but negatively related to the fine particle-size fractions (r = -0.92, p < 0.01), the sum of the amorphous Fe and Al oxides (r = -0.67, p < 0.05) and the P sorption capacity (r = -0.59, p < 0.05). The ditch sediments from residential area had a higher P release risk than that from the other ditches of forestland, sloping cropland and paddy field. The P sorption index (PSI) derived from single-point measurement was significantly correlated with the P sorption capacity (r = 0.99, p < 0.01), and could be used for estimating Qm as 1.64 times PSI plus 24.0 (Qm = 1.64 PSI + 24.0) for similar sediments with highly calcareous soils and sediments. Ditch cleaning and sediment removal for the ditch in residential area were recommended in this area to reduce the P release risk.展开更多
Accelerated soil erosion and land degradation represent major environmental problems for agricultural lands.Reliable information on the rates of soil loss is urgently needed.The traditional techniques for documenting ...Accelerated soil erosion and land degradation represent major environmental problems for agricultural lands.Reliable information on the rates of soil loss is urgently needed.The traditional techniques for documenting rates of soil loss may meet this need,but face many limitations.The fallout radionuclides,especially 137 Cs and 210 Pb ex,are increasingly used as effective tracers to quantify soil erosion rates,and they represent a valuable complement to the existing classical methods.This paper aims to introduce the basis for assessing soil erosion rates on cultivated and uncultivated slopes by using 137 Cs and 210 Pb ex measurements,to compare the 137 Cs and 210 Pb ex reference inventories,and to report several case studies undertaken in the hilly area of Sichuan Basin and the Three Gorges area of China.展开更多
Using the broadband seismic data of the regional stations in the Sichuan Digital Seismic Network and the mobile seismic stations in this region,the receiver function inversion method was adopted to study the character...Using the broadband seismic data of the regional stations in the Sichuan Digital Seismic Network and the mobile seismic stations in this region,the receiver function inversion method was adopted to study the characteristics of crustal flow and dynamic effects in Sichuan and adjacent areas. The results show that: Velocity in the crust and upper mantle of the Sichuan basin is significantly higher than that beneath the eastern margin of the Qinghai-Tibetan plateau. The velocity v_S is from 3. 6 to 3. 8km / s in the crust and4. 5- 4. 8km / s in the upper mantle beneath the basin,and there is no low-velocity layer in the crust. The lithology shows a hard block. The v_S velocity in the eastern margin of the Qinghai-Tibetan plateau is lower,with average v_Sof 3. 0- 3. 4km / s in the mid crust and4. 0- 4. 5km / s in the upper mantle. Low-velocity layers are distributed widely in the crust,most of which are in the mid crust at a depth of 20km- 40 km,and there are also a few low-velocity layers appearing in the upper crust at depths of 10km- 20 km and the lower crust at depths of 40km- 60 km. Affected by the northward pushing of the Indian plate,the eastward movement of the eastern margin of the Qinghai-Tibetan plateau is blocked by the hard Sichuan basin,producing a southward and southeastward component.Such movement process is produced by the complicated forces acting in this area. Just under the action of these forces, the eastern margin of the Qinghai-Tibetan plateau becomes a region with complicated geology and intensive earthquake activity. Obstructed by the hard Sichuan basin,the low-velocity crustal flow is delaminated and split into two or three upward and downward tributaries. The upward flow intruded into the upper crust,causing uplift of the earths urface,forming mountain crests; the downward flow intruded into the lower crust and upper mantle,resulting in thickening of the crust and depression of the Moho. The crustal flow in the eastern margin of the Qinghai-Tibetan plateau is mainly distributed along the active faults. The crustal flow flows out from the Qiangtang block in the middle part of the eastern margin of the Qinghai-Tibetan plateau,the mainstream flows along the NW-SE trending Xianshuihe fault zone,then turns NS and flows to the south along the Anninghe and Xiaojiang faults. There is another crustal flow in the north of the study area,flowing in the NE and E-W directions to the Longmenshan faults.展开更多
基金supports from the Western Development Plan of CAS (No. KZCX2-XB3-09)the Project of National Science & Technology Pillar Program (No. 2011BAD31B03)
文摘Stormwater runoff in rural townships has a high potential for water quality impairment but little information is available on strormwater runoff pollution from rural townships.To investigate the characteristics of runoff pollution in a rural township,a catchment(2.32 ha) in Linshan Township,Sichuan,China was selected to examine runoff and quality parameters including precipitation,flow rate,and total nitrogen(TN),dissolved nitrogen(DN),total phosphorus(TP),dissolved phosphorus(DP),particulate phosphorus(PP),chemical oxygen demand(COD) and suspended solid(SS) in 12 rainfall events occurring between June 2006 and July 2007.Results show that the annual pollutant loads were 47.17 kg ha-1 for TN,6.64 kg ha-1 for TP,1186 kg ha-1 for COD,and 4297 kg ha-1 for SS.DN and PP were the main forms of nitrogen and phosphorus in stormwater runoff.TP,COD and SS showed medium mass first flushes,in which nearly 40% of the total pollutant masses were transported by the first 30% of total flow volume.The peak of pollutant concentration appeared before the peak of runoff due to the first flush of accumulative pollutants in impervious areas and drainage ditches.The EMC values of TN,TP,DN and PP were negatively correlated to the maximum rainfall intensity,precipitation,total flow volume,and runoff duration(P<0.05,n=12),while EMC of COD and SS were not related to any rainfall characteristics.The FF30(FF,First Flush) for TN,TP,COD and SS were positively correlated to the maximum rainfall intensity(P<0.05,n=12),and TP was also positively correlated to the average rainfall intensity(P<0.05,n=12),indicating that the magnitude of first flush increased with the rainfall intensity in the Linshan Township.
基金provided by the Innovative Team Program of Chinese Academy of Sciences (Grant No.KZZD-EW-TZ-06)the National Natural Science Foundation of China (Grant No.41430750)the National Science & Technology Pillar Program (Grant No.2011BAD31B03)
文摘Hydrological and hydro-chemical monitoring of nitrogen(N) and phosphorus(P) in a small urbanized catchment was conducted in the hilly area of the central Sichuan Basin,China,from 2010 through 2011.The diffuse N and P loadings in different forms of total nitrogen(TN) and phosphorus(TP),dissolved nitrogen(DN) and phosphorus(DP),as well as particulate nitrogen(PN) and phosphorus(PP) were calculated based on runoff discharges and chemical analyses.The results revealed that the diffuse pollution concentrations of TN,DN,PN,TP,DP and PP exhibited large variations during rainfall events,with peak concentrations occurring during the initial period.For all of the measured parameters,the event mean concentrations(EMCs) were observed to clearly vary among rainfall events.The EMCs of TN,DN,PN,TP,DP and PP(for all of the observed rainfall events) were 10.04,6.62,3.42,1.30,0.47 and0.83 mg/L,respectively.The losses of diffuse N and P exhibited clear seasonal patterns and mainly occurred during the period from July through September,when the losses totaled 99.3 and 9.6 kg/ha for TN and TP,respectively,accounting for 75% and 74% of the total annual loadings.The mean annual loadings of TN and TP were 124.6 and 12.9 kg/ha,respectively.The results indicate that residential areas in the hilly areaof the central Sichuan Basin are subject to high diffuse N and P loadings,posing a serious risk to the receiving water quality.Ecological buffering belts are recommended to incorporate into the urbanized catchment to reduce diffuse pollution.
基金supported jointly by the CAS Action Plan for the Development of Western China (Grant No. KZCX2-XB3-09)the Key Project in the National Science and Technology Pillar Program of China (Grant No. 2011BAD31B03)
文摘Investigation of phosphorus (P) sorption-desorption characteristics of drainage ditch sediments is important for better understanding on sediment P transport behaviors in ditches. Surface ditch sediment samples were collected from headwater sub-catchment of forestland, sloping cropland, paddy field, and residential area in a representative catchment in the central Sichuan Basin. These sediment samples were used for determination of P sorption-desorption characteristics by a batch equilibrium technique. Results showed that the maximum P sorption capacities (Qm) in the sediments ranged from 159.7 to 263.7 mg/kg, while higher Qm were observed in the ditch sediments from the paddy fields. The Qm was significantly and positively correlated with oxalate-extractable Fe and Al oxides (r=0.97 and 0.98, p < 0.01), clay fraction (r = 0.78, p < 0.05) and organic matter (r = 0.95, p < 0.01). Sediment pH, clay and organic matter influenced the P sorption through amorphous Fe and Al oxides. CaCO3 content was negatively correlated with the Qm (r = -0.83, p < 0.05), implying that saturated CaCO3 (> 50 g/kg) would not increase P sorption capacity in the ditch sediments. The ditch sediments featured a linear desorption curve, suggesting that P release risk would be enhanced with the increase of the P adsorption. The P desorption rate was positively correlated with Olsen P (r = 0.94, p < 0.01), but negatively related to the fine particle-size fractions (r = -0.92, p < 0.01), the sum of the amorphous Fe and Al oxides (r = -0.67, p < 0.05) and the P sorption capacity (r = -0.59, p < 0.05). The ditch sediments from residential area had a higher P release risk than that from the other ditches of forestland, sloping cropland and paddy field. The P sorption index (PSI) derived from single-point measurement was significantly correlated with the P sorption capacity (r = 0.99, p < 0.01), and could be used for estimating Qm as 1.64 times PSI plus 24.0 (Qm = 1.64 PSI + 24.0) for similar sediments with highly calcareous soils and sediments. Ditch cleaning and sediment removal for the ditch in residential area were recommended in this area to reduce the P release risk.
基金by the National Key Technology R&D Program (2011BAD31B03)the Important National Science & Technology Specific Projects (2009ZX07104-002-06)the ActionPlan for West Development of Chinese Academy of Sciences (KZCX2-XB3-09)
文摘Accelerated soil erosion and land degradation represent major environmental problems for agricultural lands.Reliable information on the rates of soil loss is urgently needed.The traditional techniques for documenting rates of soil loss may meet this need,but face many limitations.The fallout radionuclides,especially 137 Cs and 210 Pb ex,are increasingly used as effective tracers to quantify soil erosion rates,and they represent a valuable complement to the existing classical methods.This paper aims to introduce the basis for assessing soil erosion rates on cultivated and uncultivated slopes by using 137 Cs and 210 Pb ex measurements,to compare the 137 Cs and 210 Pb ex reference inventories,and to report several case studies undertaken in the hilly area of Sichuan Basin and the Three Gorges area of China.
基金funded by the key project of National Natural Science Foundation of China(Grant No.40839909 and 41074062)
文摘Using the broadband seismic data of the regional stations in the Sichuan Digital Seismic Network and the mobile seismic stations in this region,the receiver function inversion method was adopted to study the characteristics of crustal flow and dynamic effects in Sichuan and adjacent areas. The results show that: Velocity in the crust and upper mantle of the Sichuan basin is significantly higher than that beneath the eastern margin of the Qinghai-Tibetan plateau. The velocity v_S is from 3. 6 to 3. 8km / s in the crust and4. 5- 4. 8km / s in the upper mantle beneath the basin,and there is no low-velocity layer in the crust. The lithology shows a hard block. The v_S velocity in the eastern margin of the Qinghai-Tibetan plateau is lower,with average v_Sof 3. 0- 3. 4km / s in the mid crust and4. 0- 4. 5km / s in the upper mantle. Low-velocity layers are distributed widely in the crust,most of which are in the mid crust at a depth of 20km- 40 km,and there are also a few low-velocity layers appearing in the upper crust at depths of 10km- 20 km and the lower crust at depths of 40km- 60 km. Affected by the northward pushing of the Indian plate,the eastward movement of the eastern margin of the Qinghai-Tibetan plateau is blocked by the hard Sichuan basin,producing a southward and southeastward component.Such movement process is produced by the complicated forces acting in this area. Just under the action of these forces, the eastern margin of the Qinghai-Tibetan plateau becomes a region with complicated geology and intensive earthquake activity. Obstructed by the hard Sichuan basin,the low-velocity crustal flow is delaminated and split into two or three upward and downward tributaries. The upward flow intruded into the upper crust,causing uplift of the earths urface,forming mountain crests; the downward flow intruded into the lower crust and upper mantle,resulting in thickening of the crust and depression of the Moho. The crustal flow in the eastern margin of the Qinghai-Tibetan plateau is mainly distributed along the active faults. The crustal flow flows out from the Qiangtang block in the middle part of the eastern margin of the Qinghai-Tibetan plateau,the mainstream flows along the NW-SE trending Xianshuihe fault zone,then turns NS and flows to the south along the Anninghe and Xiaojiang faults. There is another crustal flow in the north of the study area,flowing in the NE and E-W directions to the Longmenshan faults.
