| The water conservancy and schistosomiasis control project is an important part of the modernization of the schistosomiasis control system.It is a comprehensive management way to promote the positive interaction between the epidemic prevention and control,social economy and natural environment.It also enhances the sustainability of the schistosomiasis control work and achieves accurate prevention and control.It contributes to furthering optimize the spatial structure of water conservancy and schistosomiasis control project,controlling the evolution trend of epidemic risk,and alleviating the typical "person area" contradiction in low-level epidemic areas.Based on the perspective of disease geography and theoretical epidemiology,this paper focuses on the definition and identification of comprehensive risk,the suitability of engineering construction,the risk suppression mechanism of engineering and the optimal layout of engineering.It conducts researches according to the basic idea of clear warning intention,identification of warning source,monitoring of warning potential,simulation of early warning and optimization of prevention and control.Remote sensing image data,land use data,socio-economic data and epidemiological data were used to comprehensively analyze the source,carrier and driving force of schistosomiasis epidemic in Dongting Lake.The risk element structure and risk evolution characteristics were monitored and analyzed.By using K-means clustering,GAM generalized additive model,VAR vector autoregression,KDE kernel density estimation,BP neural network and Kriging difference method,the layout and construction effect of water conservancy and schistosomiasis control project,the interaction mechanism between project construction and schistosomiasis risk,and the optimal regulation of water conservancy and schistosomiasis control project were studied qualitatively and quantitatively.The main conclusions are as follows:(1)The collaborative analysis of spectral characteristic indexes such as Bi,GVI and NDVI,land use data and snail survey data can further improve the identification ability of potential snail breeding environment and risk.From 2006 to 2016,the main environmental components of potential focus areas and suspected breeding areas in Dongting Lake area were farmland,swamp wetland,land in winter and water in summer,and other woodlands.The subdivision composition of each environment type also has high similarity.The potential breeding wind in the epidemic area of Dongting Lake shows a decreasing trend from the east and north to the southwest.In the future,the spatial distribution characteristics of snail density will be changed by some natural or human factors in the areas near the lake and water.(2)From 2006 to 2016,the spatial distribution of the comprehensive risk of schistosomiasis in Dongting Lake area mainly showed the overall pattern of high in the core area and low in the peripheral area,high in the surrounding area of large lakes and low in other areas,high in the West Dongting area of Northwest Central Region and low in the East Dongting area of northeast central region.Among them,grade I and II risk areas are stably distributed in the West Dongting Lake area,the area to the north of Liu Ye lake,the South County in the hinterland of Dongting Lake,and the low-lying embankment between the above areas and Lishui River Basin.Grade III and IV risk areas are mainly distributed in the South and northeast of Dongting,including Yueyang District,Yiyang District,Huarong County,Xiangyin County,Yueyang County,etc.Regional snail status,livestock infection and dangerous environment were the epidemiological indicators with strong driving ability for epidemic risk.The land types that played a leading role in the development and control of epidemic included high coverage grassland,other construction land,reservoir pond,open forest land and marsh wet land.From high to low,the comprehensive risk of epidemic situation in the "Four Rivers" basin is respectively Lishui River,Yuanshui River,Zishui River and Xiangjiang River.(3)Based on the F.R.E.A multi-dimensional clustering and coefficient of variation method,the suitability of seven types of water conservancy and schistosomiasis control was analyzed.The projects with high adaptability to construction conditions were ditch drainage,culvert and sluice reconstruction,embankment hardening,snail pond,pond regulation,beach lifting and ditch hardening.The results show that the seven types of projects have good universality for the interaction strength and comprehensive risk level of human water epidemic water,and the suitability for social and economic functions and regional environmental characteristics are different.Affected by leading factors,such as residents' income level,patients' treatment intensity,funding for schistosomiasis control,water environment in winter,land and summer,and regional development intensity,the water conservancy and schistosomiasis control project has basically formed the action mechanism of main behavior constraint,linkage of schistosomiasis control measures,interaction of composite functions,socio-economic driving,and ecological epidemic prevention strengthening.It also drives the prevention and control of various water conservancy and schistosomiasis control projects the time and space difference of the effect.(4)BP neural network model has been used to simulate the evolution characteristics of comprehensive risk in Dongting Lake area from 2020 to 2030.The results show that the average value of comprehensive risk in the whole region first decreases and then rebounds,continuing the overall pattern from 2006 to 2016.The hot areas of comprehensive risk promotion will change from scattered and local concentration to the north to the north,and the areas north of Dongting Lake may become the main areas of comprehensive risk promotion.From the suitability of engineering construction,the necessity of engineering construction and the ability of engineering risk control,the engineering construction area is divided into four types.Among them,the key construction areas mainly present the spatial pattern of "three districts and many points",and the typical areas include Dingcheng District,Jinshi City,Lixian County,etc.The construction strategy is to increase investment,focus on construction,adjust measures to local conditions and strengthen assessment.The optimization and upgrading area mainly presents the spatial pattern along the great rivers and lakes,which is distributed along the Dongting Lake in Yueyang City,Yueyang County and Yiyang City,and in the hinterland of Lishui River,Tuojiang River and Songhu flood channel in the middle of Dongting Lake area.The construction strategies include strengthening investigation and evaluation,promoting engineering upgrading and substitution,and promoting the construction of prevention and control system.At the same time,reasonable control area and forbidden construction area also have their own spatial distribution characteristics and construction strategies. |
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