建立了非恒定河网一维水流-水质数值模型(THU-River1D),水动力模块利用最近提出的汊点水位预测-校正(junction-point water stage prediction and correction,JPWSPC)法处理缓流河网汊点处的回流效应,采用Preissmann格式离散Saint-Venan...建立了非恒定河网一维水流-水质数值模型(THU-River1D),水动力模块利用最近提出的汊点水位预测-校正(junction-point water stage prediction and correction,JPWSPC)法处理缓流河网汊点处的回流效应,采用Preissmann格式离散Saint-Venant方程组,并采用Newton-Raphson方法求解非线性离散方程;水质模块采用分步法,分别求解对流项、源(汇)项、以及纵向离散项,其中,对流项处理采用改进的四阶显式Holly-Preissmann格式。模型无需特殊的河道编码,既适用于树状又适用于环状河网,还适用于潮汐流动。展开更多
Guanting Reservoir（GR） is one of the most important water sources for Beijing and neighboring regions.Due to water pollution,it was withdrawn from the system to supply Beijing drinking water;however,after a thorough...Guanting Reservoir（GR） is one of the most important water sources for Beijing and neighboring regions.Due to water pollution,it was withdrawn from the system to supply Beijing drinking water;however,after a thorough treatment process,GR was made a reserve water source since 2007.To develop a comprehensive and quantitative analysis of water yield and purification services in the GR watershed,this study selected two time periods：the period when GR was withdrawn from the system supplying local drinking water and the period that it has been designated a reserve water source.The In VEST model was used to evaluate the quantities of water yields,and total nitrogen and total phosphorus outputs from 1995 to 2010 Additionally,the spatiotemporal variations of water yield services and water quality purification services in the GR watershed were analyzed.The results showed that water yield services in the GR watershed first weakened and then became stronger,but weakened overall during the years 1995 to 2010.Water yield capacity in the basin decreased from 1.89×10^9 m3 in 1995 to 1.43×10^9 m3 in 2010（a drop of 24.0% in total）.Water quality purification services also showed the same tendency.Total nitrogen output decreased from 4028.7 t in 1995 to 3611.4 t in 2010,while total phosphorus decreased from 379.7 t in 1995 to 354.0 t in 2010.Nitrogen and phosphorus purification services were enhanced by 10.4% and 6.8%,respectively.Changes in the climate and land use were the main factors which lead to the changes in the water yield service in the GR watershed.Policies intended to protect water resource have matched the varying trends of water quality purification services during different periods.On one hand,the research results provide a foundation to identify key fields for eco-compensation in the Guanting Reservoir basin.On another hand,the ecosystem service value will increase on the basis of eco-compensation criteria through setting the scenarios of returning farmland to forest and ecological protection.This method directly reflects increases in ecosystem service values that have occurred since measures to protect the ecological environment have been implemented.This method is more persuasive and feasible than using eco-compensation criteria based on regional ecosystem service values determined by land use/coverage type.It can provide a new way to assess eco-compensation in the Guanting Reservoir basin and other regions.展开更多
文摘建立了非恒定河网一维水流-水质数值模型(THU-River1D),水动力模块利用最近提出的汊点水位预测-校正(junction-point water stage prediction and correction,JPWSPC)法处理缓流河网汊点处的回流效应,采用Preissmann格式离散Saint-Venant方程组,并采用Newton-Raphson方法求解非线性离散方程;水质模块采用分步法,分别求解对流项、源(汇)项、以及纵向离散项,其中,对流项处理采用改进的四阶显式Holly-Preissmann格式。模型无需特殊的河道编码,既适用于树状又适用于环状河网,还适用于潮汐流动。
基金National Natural Science Foundation of China(51379084)National Key R&D Plan(2016YFC0503405)
文摘Guanting Reservoir（GR） is one of the most important water sources for Beijing and neighboring regions.Due to water pollution,it was withdrawn from the system to supply Beijing drinking water;however,after a thorough treatment process,GR was made a reserve water source since 2007.To develop a comprehensive and quantitative analysis of water yield and purification services in the GR watershed,this study selected two time periods：the period when GR was withdrawn from the system supplying local drinking water and the period that it has been designated a reserve water source.The In VEST model was used to evaluate the quantities of water yields,and total nitrogen and total phosphorus outputs from 1995 to 2010 Additionally,the spatiotemporal variations of water yield services and water quality purification services in the GR watershed were analyzed.The results showed that water yield services in the GR watershed first weakened and then became stronger,but weakened overall during the years 1995 to 2010.Water yield capacity in the basin decreased from 1.89×10^9 m3 in 1995 to 1.43×10^9 m3 in 2010（a drop of 24.0% in total）.Water quality purification services also showed the same tendency.Total nitrogen output decreased from 4028.7 t in 1995 to 3611.4 t in 2010,while total phosphorus decreased from 379.7 t in 1995 to 354.0 t in 2010.Nitrogen and phosphorus purification services were enhanced by 10.4% and 6.8%,respectively.Changes in the climate and land use were the main factors which lead to the changes in the water yield service in the GR watershed.Policies intended to protect water resource have matched the varying trends of water quality purification services during different periods.On one hand,the research results provide a foundation to identify key fields for eco-compensation in the Guanting Reservoir basin.On another hand,the ecosystem service value will increase on the basis of eco-compensation criteria through setting the scenarios of returning farmland to forest and ecological protection.This method directly reflects increases in ecosystem service values that have occurred since measures to protect the ecological environment have been implemented.This method is more persuasive and feasible than using eco-compensation criteria based on regional ecosystem service values determined by land use/coverage type.It can provide a new way to assess eco-compensation in the Guanting Reservoir basin and other regions.
