Main Water Resource Development Goals for The Next Five Years

The system for flood control and disaster relief should be upgraded. Flood- control systems for major rivers and lakes should be built. Broken dikes for water reservoirs should be repaired. An

WATER RESOURCES DEVELOPMENT IN CHINA

The sustainable development of water resources is of vital importance to the maintenance of survival environment on which people rely for existence. A brief review is given on the characteristic features of water resources, the present status of water resources development and some major water conservancy projects under construction or in contemplation in China. Finally, the prospect of water resource development in

Identification and Evolution of Groundwater Chemistry in the Ejin Sub-Basin of the Heihe River, Northwest China

Hydro-chemical characteristics of groundwater and their changes as affected by human activities were studied in the Ejin Sub-Basin of the Inner Mongolia Autonomous Region, China, to understand the groundwater evolution, to identify the predominant geochemical processes taking place along the horizontal groundwater flow path, and to characterize anthropogenic factors affecting the groundwater environment based on previous data. The concentrations of major ions and total dissolved solids （TDS） in the groundwater showed a great variation, with 62.5% of the samples being brackish （TDS ≥ 1 000 mg L^-l）. The groundwater system showed a gradual hydro-chemical zonation composed of Na^＋ -HCO3^-, Na^＋ -Mg^2＋ -SO4 ^2 -Cl^-, and Na^＋ -Cl^-. The relationships among the dissolved species allowed identification of the origin of solutes and the processes that generated the observed water compositions. The dissolution of halite, dolomite, and 2- gypsum explained, in part, the presence of Na^＋, K^＋, Cl^-, SO^4 , and Ca^2＋, but other processes, such as mixing, Na^＋ exchange for Ca^2＋ and Mg^2＋, and calcite precipitation also contributed to the composition of water. Human activity, in particular large-scale water resources development associated with dramatic population growth in the last 50 years, has led to tremendous changes in the groundwater regime, which reflected in surface water runoff change, decline of groundwater table and degeneration of surface water and groundwater quality. Solving these largely anthropogenic problems requires concerted, massive and long-term efforts.

Dynamics of freshwater snails and Schistosoma infection prevalence in schoolchildren during the construction and operation of a multipurpose dam in central Côte d’Ivoire

Background:The construction and operation of small multipurpose dams in Africa have a history of altering the transmission of water-based diseases,including schistosomiasis.The current study was designed to investigate the abundance and dynamics of schistosomiasis intermediate host snails and Schistosoma infections in humans during the construction and the first years of operation of a small multipurpose dam in Côte d’Ivoire.Methods:The study was carried out in Raffierkro and four neighbouring villages in central Côte d’Ivoire between 2007 and 2012.Snails were collected by two experienced investigators using scoops and forceps for 15 min at each site.Snails were identified at genera and,whenever possible,species level,and subjected to testing for cercarial shedding.Schoolchildren aged 6-15 years were examined once every year for Schistosoma haematobium and S.mansoni infection,using urine filtration and duplication Kato-Katz thick smears,respectively.Additionally,551 adults were examined for Schistosoma infection before(June 2007)and 359 individuals 2 years after dam construction(June 2009).Results:Overall,1700 snails belonging to nine different genera were collected from 19 sampling sites.Bulinus(potential intermediate host snails of S.haematobium)and Pila were the most common genera,whereas Biomphalaria(potential intermediate host snail of S.mansoni),Lymnaea,Physa and Melanoides were found in two villages.During the first-year sampling period,65 snails were collected,of which 13(20%)were schistosomiasis intermediate hosts.In subsequent years,out of 1635 snails collected,1079(66%)were identified as potential intermediate host for schistosomiasis,but none were shedding cercariae.The prevalence of S.mansoni among adults in the study area was low(0.4%in 2007 and 0.3%in 2009),whereas the prevalence of S.haematobium declined from 13.9%to 2.9%in this two-year period.Conclusions:The low prevalence of schistosomiasis in humans and the absence of infected intermediate host snails during the construction and early phase of operation of a small multipurpose dam suggest that there was no or only very little local transmission.However,the considerable increase in the number of intermediate host snails and their dispersion in irrigation canals call for rigorous surveillance,so that adequate public health measures can be taken in case of early signs of an outbreak.

The economic impact of schistosomiasis

Background:The economic impact of schistosomiasis and the underlying tradeofs between water resources devel‑opment and public health concerns have yet to be quantifed.Schistosomiasis exerts large health,social and fnan‑cial burdens on infected individuals and households.While irrigation schemes are one of the most important policy responses designed to reduce poverty,particularly in sub-Saharan Africa,they facilitate the propagation of schistoso‑miasis and other diseases.Methods:We estimate the economic impact of schistosomiasis in Burkina Faso via its efect on agricultural produc‑tion.We create an original dataset that combines detailed household and agricultural surveys with high-resolution geo-statistical disease maps.We develop new methods that use the densities of the intermediate host snails of schis‑tosomiasis as instrumental variables together with panel,spatial and machine learning techniques.Results:We estimate that the elimination of schistosomiasis in Burkina Faso would increase average crop yields by around 7%,rising to 32%for high infection clusters.Keeping schistosomiasis unchecked,in turn,would correspond to a loss of gross domestic product of approximately 0.8%.We identify the disease burden as a shock to the agricultural productivity of farmers.The poorest households engaged in subsistence agriculture bear a far heavier disease burden than their wealthier counterparts,experiencing an average yield loss due to schistosomiasis of between 32 and 45%.We show that the returns to water resources development are substantially reduced once its health efects are taken into account:villages in proximity of large-scale dams sufer an average yield loss of around 20%,and this burden decreases as distance between dams and villages increases.Conclusions:This study provides a rigorous estimation of how schistosomiasis afects agricultural production and how it is both a driver and a consequence of poverty.It further quantifes the tradeof between the economics of water infrastructures and their impact on public health.Although we focus on Burkina Faso,our approach can be applied to any country in which schistosomiasis is endemic.