Evaluation on Risk of Non-Point Source Pollution in Dayanghe Watershed Based on GIS

2012 ◽  
Vol 209-211 ◽  
pp. 2023-2026
Author(s):  
An Ning Suo ◽  
Hua Ru Wang ◽  
Yuan Bin Fu

Four indices which include surface runoff, soil erosion, agricultural nutrient loss, human and animal feces were selected and method to evaluate risk of non-point source pollution in watershed was constructed based on GIS. As a case, non-point source pollution in Dayanghe was evaluated. Results showed that very high risk area of non-point source pollution accounted for 3.41% area of the watershed, mainly located in farmland with steep slope along upper valley of the watershed. High risk area of non-point source pollution was located in farmland and human settlement placecs, accounted for 16.40% area of the watershed. Areas with low risk of non-point source pollution was riverbeds, shrub and grassland in eastern and western hilly with steep slope. Areas with lower risk of non-point source pollution located in middle of the watershed and accounted for 60.55% area. GIS-based risk evaluation system of non-point source pollution can reflect real map of pollution in the Dayanghe watershed and give implication for protection plan.

2011 ◽  
Vol 356-360 ◽  
pp. 771-776
Author(s):  
Cheng Wu ◽  
Guo Chun Deng ◽  
Yan Li ◽  
Zhi Ying Li ◽  
Shu Hua Yang

A rapid quantitative risk evaluation system of non-point source pollution (NPSP), based on comprehensive consideration of various factors such as topographic features, land use construction, annual mean precipitation, soil erosion characteristics and pollutant removal cost, was constructed using an Spatial Analysis Module of GIS on watershed scale. We investigated the risk pattern of NPSP in the Dianchi Lake Watershed using the rapid risk assessment system. The results indicated that NPSP risk pattern showed the arc or normal distribution trend in the Dianchi Lake Basin, namely the medium risk area of NPSP is the largest (about 1311 km2). Moreover, the spatial difference of high risk NPSP pattern is remarkable: the high risk region for NPSP was primarily in the 10 km range of the southern and eastern parts and the 5 km range of western part around the Dianchi Lake.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Kang-wen Zhu ◽  
Zhi-min Yang ◽  
Lei Huang ◽  
Yu-cheng Chen ◽  
Sheng Zhang ◽  
...  

AbstractTo determine the risk state distribution, risk level, and risk evolution situation of agricultural non-point source pollution (AGNPS), we built an ‘Input-Translate-Output’ three-dimensional evaluation (ITO3dE) model that involved 12 factors under the support of GIS and analyzed the spatiotemporal evolution characteristics of AGNPS risks from 2005 to 2015 in Chongqing by using GIS space matrix, kernel density analysis, and Getis-Ord Gi* analysis. Land use changes during the 10 years had a certain influence on the AGNPS risk. The risk values in 2005, 2010, and 2015 were in the ranges of 0.40–2.28, 0.41–2.57, and 0.41–2.28, respectively, with the main distribution regions being the western regions of Chongqing (Dazu, Jiangjin, etc.) and other counties such as Dianjiang, Liangping, Kaizhou, Wanzhou, and Zhongxian. The spatiotemporal transition matrix could well exhibit the risk transition situation, and the risks generally showed no changes over time. The proportions of ‘no-risk no-change’, ‘low-risk no-change’, and ‘medium-risk no-change’ were 10.86%, 33.42%, and 17.25%, respectively, accounting for 61.53% of the coverage area of Chongqing. The proportions of risk increase, risk decline, and risk fluctuation were 13.45%, 17.66%, and 7.36%, respectively. Kernel density analysis was suitable to explore high-risk gathering areas. The peak values of kernel density in the three periods were around 1110, suggesting that the maximum gathering degree of medium-risk pattern spots basically showed no changes, but the spatial positions of high-risk gathering areas somehow changed. Getis-Ord Gi* analysis was suitable to explore the relationships between hot and cold spots. Counties with high pollution risks were Yongchuan, Shapingba, Dianjiang, Liangping, northwestern Fengdu, and Zhongxian, while counties with low risks were Chengkou, Wuxi, Wushan, Pengshui, and Rongchang. High-value hot spot zones gradually dominated in the northeast of Chongqing, while low-value cold spot zones gradually dominated in the Midwest. Our results provide a scientific base for the development of strategies to prevent and control AGNPS in Chongqing.


2020 ◽  
Author(s):  
Kang-wen ZHU ◽  
Zhi-min YANG ◽  
Lei HUANG ◽  
Yu-cheng CHEN ◽  
Sheng ZHANG ◽  
...  

Abstract To determine the risk state distribution, risk level, and risk evolution situation of agricultural non-point source pollution (AGNPS), we built an ‘Input-Translate-Output’ three-dimensional evaluation (ITO3dE) model that involved 12 factors under the support of GIS and analyzed the spatiotemporal evolution characteristics of AGNPS risks from 2005 to 2015 in Chongqing by using GIS space matrix, kernel density analysis, and Getis-Ord Gi* analysis. Land use changes during the 10 years had a certain influence on the AGNPS risk. The risk values in 2005, 2010, and 2015 were in the ranges of 0.40–2.28, 0.41–2.57, and 0.41–2.28, respectively, with the main distribution regions being the western regions of Chongqing (Dazu, Jiangjin, etc.) and other counties such as Dianjiang, Liangping, Kaizhou, Wanzhou, and Zhongxian. The spatiotemporal transition matrix could well exhibit the risk transition situation, and the risks generally showed no changes over time. The proportions of ‘no-risk no-change’, ‘low-risk no-change’, and ‘medium-risk no-change’ were 10.86%, 33.42%, and 17.25%, respectively, accounting for 61.53% of the coverage area of Chongqing. The proportions of risk increase, risk decline, and risk fluctuation were 13.45%, 17.66%, and 7.36%, respectively. Kernel density analysis was suitable to explore high-risk gathering areas. The peak values of kernel density in the three periods were around 1,110, suggesting that the maximum gathering degree of medium-risk pattern spots basically showed no changes, but the spatial positions of high-risk gathering areas somehow changed. Getis-Ord Gi* analysis was suitable to explore the relationships between hot and cold spots. Counties with high pollution risks were Yongchuan, Shapingba, Dianjiang, Liangping, northwestern Fengdu, and Zhongxian, while counties with low risks were Chengkou, Wuxi, Wushan, Pengshui, and Rongchang. High-value hot spot zones gradually dominated in the northeast of Chongqing, while low-value cold spot zones gradually dominated in the Midwest. Our results provide a scientific base for the development of strategies to prevent and control AGNPS in Chongqing.


2014 ◽  
Vol 1073-1076 ◽  
pp. 1017-1022
Author(s):  
Xiao Kang Wu ◽  
Chun Ming Ye ◽  
Yong Lin Li ◽  
Jia Wu

Initial rainwater pollution is an important non-point source pollution of urban drainage systems. The application of storage tanks and other reduction facilities has play a key role in reducing first flush pollution. Because of the lack of scientific evaluation system, the evaluation is disorderly and there are many operational problems. This case is based on the reduction facilities research of Suzhou Creek in Shanghai, through which a standard evaluation system and implementation procedure are built to perfect the incomprehensive and unscientific system, so that the efficiency can be improved.


2021 ◽  
Vol 50 (Supplement_1) ◽  
pp. i12-i42
Author(s):  
K Suseeharan ◽  
T Vedutla

Abstract Background The Royal College of Physician guidelines (2011) identified handover as a “high risk step” in patient care, especially in recent times within the NHS where shift patterns lead to more disjointed care with a high reliance on effective handover by all staff members. Introduction At Cannock Chase hospital, Fairoak ward is an elderly care rehabilitation ward where there is a large multi-disciplinary team. While working on the ward as doctors we noticed that handover between the MDT was poor. Anecdotal evidence from both doctors and nurses felt that this was a high risk area in need of improvement. Aim to improve handover between doctors and nurses on this elderly care ward. Method To measure the quality of current handover practice we did a questionnaire. A total of 12 questionnaires were completed which showed that 92% of staff felt that handover on the ward was very poor and 50% preferred both written and verbal handover. We measured the number of tasks verbally handed over between doctors and nurses over 3 days. On average 65% of the tasks were completed. We then made the below interventions and re-audited to see if there was any improvement. Interventions over 3 week period: Results Questionnaire: Measuring task completion after interventions; Conclusion This project has made a positive change qualitatively and quantitatively to the ward handover practice. Staff satisfaction regarding handover has improved and the number of “handed over” tasks completed daily has significantly improved. The written handover sheet had poor utilisation by staff but in 4 months we are going to re-audit and trial the handover sheet again to further improve service delivery. We hope this improvement will have a positive impact on patient care on this elderly care ward.


Water ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 1955
Author(s):  
Mingxi Zhang ◽  
Guangzhi Rong ◽  
Aru Han ◽  
Dao Riao ◽  
Xingpeng Liu ◽  
...  

Land use change is an important driving force factor affecting the river water environment and directly affecting water quality. To analyze the impact of land use change on water quality change, this study first analyzed the land use change index of the study area. Then, the study area was divided into three subzones based on surface runoff. The relationship between the characteristics of land use change and the water quality grade was obtained by grey correlation analysis. The results showed that the land use types changed significantly in the study area since 2000, and water body and forest land were the two land types with the most significant changes. The transfer rate is cultivated field > forest land > construction land > grassland > unused land > water body. The entropy value of land use information is represented as Area I > Area III > Area II. The shift range of gravity center is forest land > grassland > water body > unused land > construction land > cultivated field. There is a strong correlation between land use change index and water quality, which can be improved and managed by changing the land use type. It is necessary to establish ecological protection areas or functional areas in Area I, artificial lawns or plantations shall be built in the river around the water body to intercept pollutants from non-point source pollution in Area II, and scientific and rational farming in the lower reaches of rivers can reduce non-point source pollution caused by farming.


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