Water quality changing trends of the Miyun Reservoir

In order to simulate changes in the water quality of the Miyun Reservoir dueto continuous descent of surface water level, a 3-D ecological hydrodynamic model was developedthrough coupling the water quality analysis simulation program (WASP) with the environmental fluiddynamics code (EFDC). The model was then calibrated and verified. Four scenarios (S1, S21, S22 andS23) were simulated using the model. Results show that the water quality of the Miyun Reservoirunder conditions of low surface water level is apparently affected by different amounts of inflowand different total phosphorus (TP) loadings. The chlorophyll-a concentration might exceed 10 μg/Lin many areas of the Miyun Reservoir (This limitative value is seen as a critical value ofeutrophication) when large loadings of TP enter due to the amount of inflow increasing. Results ofscenario S23 indicate that control of TP loadings can decrease chlorophyll-a concentrationeffectively, and the water quality of the Miyun Reservoir will improve or retain its status quo.

The Process of Cultivated Land and Water Resource Distribution Changing in Recent Decades in Upstream and Downstream in Shiyang Inland River Basin in Arid Area of Northwest China

Last century 50 - 70 years, the dam construction of Shiyang Inland River Basin (SIRB) profound impact on the distribution of water resources and arable land in the basin. Through data collection, field surveys and remote sensing image interpretation, we analysis the use of land and water resources change process in the middle and lower reaches of SIRB in recent decades. The results show: (1) The cultivated area of SIRB has been an upward trend in recent decades, The whole basin cultivated area has increased total 229,000 hm2 from 1973 to 2010 and mainly in the middle and lower reaches. Midstream increased by 149,700 hm2 accounting for 65.36 percent of total, downstream increased by 70,000 hm2 accounting for 30.70 percent of total. (2) The amount of surface water resources of downstream reduce significantly gradually since dam construction, and the water table sharp decline. While the volume of surface water resources come downstream from the 1950s accounted for 30 to 40 percent of the total gradually reduced to less than 10% in 2012;(3) since the arable land area of middle and lower reaches of SIRB basin substantial increase, so the surface water resource does not meet irrigation needs. Agricultural irrigation relies heavily on exploitation of groundwater to supplement, resulting in Regional Groundwater Depth dropped rapidly, and forming several huge funnel groundwater settlements. 20 years from 1981 to 2001 the groundwater level of midstream dropped from around 5m to around 10m in Wuwei, and in Minqin dam-region of downstream along faster rate of decline in 20 years fell from 8.52 m to 22.68 m. Dam construction project has changed the pattern of the basin water cycle, the middle reaches closure a large number of surface water resources led to downstream sharp decline. Downstream continued exploitation of groundwater formed a few huge funnel groundwater settlements, it caused serious ecological problems. The basin should adjust the industrial structure and develop water saving irrigation, promote a virtuous cycle of water resources, to achieve sustainable development, seek a sustainable development ways conversion natural oasis to artificial oasis efficiency in arid zone.

Characteristics and Trend Variation of Light,Temperature and Water Resources in Dongling District of Shenyang Province in Recent 49 Years

The meteorological data of light,temperature and water during 1961-2009 were selected to analyze the trend variation of climatic resources and provide the basis for developing and utilizing local climate resources.The results indicated that light resource presented the decreasing tendency in Dongling District,annual radiation reduced by 528 MJ/m2,and annual sunshine duration decreased by 333 h.The heat resource presented the increasing tendency,the average annual temperature increased by 1.04 ℃,and active accumulated temperature increased by 228 ℃.The general trend of annual precipitation declined slightly,precipitation resource during every age changed slightly and would tend to be stable.

Climate change, water resources and sustainable development in the arid and semi-arid lands of Central Asia in the past 30 years

The countries of Central Asia are collectively known as the five "-stans": Uzbekistan, Kyrgyzstan, Turkmenistan, Tajikistan and Kazakhstan. In recent times, the Central Asian region has been affected by the shrinkage of the Aral Sea, widespread desertification, soil salinization, biodiversity loss, frequent sand storms, and many other ecological disasters. This paper is a review article based upon the collection, identification and collation of previous studies of environmental changes and regional developments in Central Asia in the past 30 years. Most recent studies have reached a consensus that the temperature rise in Central Asia is occurring faster than the global average. This warming trend will not only result in a higher evaporation in the basin oases, but also to a significant retreat of glaciers in the mountainous areas. Water is the key to sustainable development in the arid and semi-arid regions in Central Asia. The uneven distribution, over consumption, and pollution of water resources in Central Asia have caused severe water supply problems, which have been affecting regional harmony and development for the past 30 years. The widespread and significant land use changes in the 1990 s could be used to improve our understanding of natural variability and human interaction in the region. There has been a positive trend of trans-border cooperation among the Central Asian countries in recent years. International attention has grown and research projects have been initiated to provide water and ecosystem protection in Central Asia. However, the agreements that have been reached might not be able to deliver practical action in time to prevent severe ecological disasters. Water management should be based on hydrographic borders and ministries should be able to make timely decisions without political intervention. Fully integrated management of water resources, land use and industrial development is essential in Central Asia. The ecological crisis should provide sufficient motivation to reach a consensus on unified water management throughout the region.

Influencing factors of water resources in the source region of the Yellow River

Taking the source region of the Yellow River as a study area and based on the data from Madoi Meteorological Station and Huangheyan Hydrological Station covering the period 1955-2005, this paper analyses the changing trends of surface water resources, climate and frozen ground and reveals their causes. Results show that there exist frequent fluctuations from high to low water flow in the 51-year period. In general, the discharge has shown a de- clining trend in the 51 years especially since the 1990s. The annual distribution shows one peak which, year on year is getting smaller. （1） Precipitation has a significant and sustained influence on discharge. （2） A sharp rise of temperature resulted in the increase of evaporation and the decrease of discharge, which has a greater effect than on ice-snow melting. （3） Frozen ground tends to be degraded markedly. There is a significant positive correlation be- tween the permafrost thickness and the discharge. （4） Evaporation rates are significantly increasing, leading to the decrease of discharge. 70% of the discharge reduction resulted from climate change, and the remaining 30% may have been caused by human activities.

Impacts of climate change on agricultural water resources and adaptation on the North China Plain

Climate change is having a considerable impact on the availability of water resources for agricultural production on the North China Plain （NCP）, where the shortage of water is currently disturbing the stability and sustainability of agricultural production with respect to the drying tendency since the 1950s. However, although potential evapotranspiration （ET） has shown a decreasing trend under climate change, actual ET has slightly increased with an acceleration in hydrological cycling. Global climate model （GCM） ensemble projections predict that by the 2050s, the increased crop water demand and intensified ET resulting from global warming will reduce water resources surplus （Precipitation-ET） about 4%-24% and increase significantly the irrigation water demand in crop growth periods. This study assesses possible mitigation and adaptation measures for enabling agricultural sustainability. It is revealed that reducing the sowing area of winter wheat （3.0%-15.9%） in water-limited basins, together with improvement in crop water-use efficiency would effectively mitigate water shortages and intensify the resilience of agricultural systems to climate change.

Sensitivity and vulnerability of water resources in the arid Shiyang River Basin of Northwest China

The sensitivity and vulnerability of water resources to climate change is difficult to assess. In this study, we used a conceptual hydrologic model to investigate the sensitivity of streamflow to climate change. We also pro- posed a framework to evaluate the vulnerability of water resources in arid regions. We applied this framework to a case study of the Shiyang River Basin in Northwest China. Results showed that the precipitation and streamflow in Shiyang River Basin exhibited no significant trends of change from 1956 to 2010. In the past five decades, however, the temperature increased significantly by 0.37℃ per decade. According to the sensitivity assessment, a 10% in- crease in precipitation and a 1℃ increase in temperature altered mean annual streamflow by averages of 14.6% and -0.5%, respectively, from 1988 to 2005. In the 2000s, the calculated vulnerability of water resources in Shiyang River Basin was more than 0.95, indicating severe vulnerability. The increase in the amount of precipitation and the imple- mentation of water-saving measures can reduce the vulnerability of water resources in the future; if precipitation in- creases by 10% per decade and the use of irrigation water decreases by 15% in the 2030s, the evaluated value of water resources vulnerability will be reduced to 0.79. However, the region remains highly vulnerable. The proposed framework for vulnerability assessment can be applied to the arid regions in Northwest China, and the results of our efforts can identify adaptation strategies and improve the management of water resources in such regions.

Impacts of climate change and human activities on water resources in the Ebinur Lake Basin, Northwest China

Changing climatic conditions and extensive human activities have influenced the global water cycle.In recent years,significant changes in climate and land use have degraded the watershed ecosystem of the Ebinur Lake Basin in Xinjiang,Northwest China.In this paper,variations of runoff,temperature,precipitation,reference evapotranspiration,lake area,socio-economic water usage,groundwater level and water quality in the Ebinur Lake Basin from 1961 to 2015 were systematically analyzed by the Mann-Kendall test methods(M-K)mutation test,the cumulative levelling method,the climate-sensitive method and land-use change index.In addition,we evaluated the effects of human activities on land use change and water quality.The results reveal that there was a significant increase in temperature and precipitation from 1961 to 2015,despite a decrease in reference evapotranspiration.The Wenquan station was not significantly affected by human activities as it is situated at a higher altitude.Runoff at this station increased significantly with climate warming.In contrast,runoff at the Jinghe station was severely affected by numerous human activities.Runoff decreased without obvious fluctuations.The contributions of climate change to runoff variation at the Jinghe and Wenquan stations were 46.87%and 58.94%,respectively;and the contributions of human activities were 53.13%and 41.06%,respectively.Land-use patterns in the basin have changed significantly between 1990 and 2015:urban and rural constructed lands,saline-alkali land,bare land,cultivated land,and forest land have expanded,while areas under grassland,lake,ice/snow and river/channel have declined.Human activities have dramatically intensified land degradation and desertification.From 1961 to 2015,both the inflow into the Ebinur Lake and the area of the lake have declined year by year;groundwater levels have dropped significantly,and the water quality has deteriorated during the study period.In the oasis irrigation area below the runoff pass,human activities mainly influenced the utilization mode and quantity of water resources.Changes in the hydrology and quantity of water resources were driven primarily by the continuous expansion of cultivated land and oasis,as well as the growth of population and the construction of hydraulic engineering projects.After 2015,the effects of some ecological protection projects were observed.However,there was no obvious sign of ecological improvement in the basin,and some environmental problems continue to persist.On this basis,this study recommends that the expansion of oasis should be limited according to the carrying capacity of the local water bodies.Moreover,in order to ensure the ecological security of the basin,it is necessary to determine the optimal oasis area for sustainable development and improve the efficiency of water resources exploitation and utilization.

Assessing the impacts of climate change on water resources of a West African trans-boundary river basin and its environmental consequences (Senegal River Basin)

The Senegal River Basin （SRB） is a shared watershed in West Africa which includes regions （the upper basin, valley, and delta）, characterized by distinct environmental conditions. An important feature of the Senegal River flow volume historically was its in- ter-annual irregularity, which caused a major water resource constrain. This situation has been accentuated during the long-term drought （1969-1984） in the Sahel zone which highlights the vulnerability of food-producing systems to climate change and variability. SRB is undergoing fundamental environmental, hydrologic, and socioeconomic traxisitions and represents a good illustration of sensi- tivity to climatic variations and opportunities for adaptation. This paper aims to study water resources systems under stress from cfi- mate variability and change in the Senegal River Basin. The results show （1） through the compilation of available data, information and knowledge （sedimentological, climatical, geological, environmental, archeological, etc.）, the chronological consequences of cli- mate change during the past millennium in West Africa, and also （2） an analysis of the recent impacts and vulnerability to climate change in the SRB and finally （3） the adaptation strategies in the SRB in order to identify and resolve problems associated with this water scarcity and to address the potential for guaranteed agricultural production in this narrow geographic area.

Assessment of Climate Change Impact on Water Resources in the Upper Senegal Basin (West Africa)

This study assesses the potential impacts of climate change on water resources and the effect of statistical bias correction on the projected climate change signal in hydrological variables over the Upper Senegal Basin (West Africa). Original and bias corrected climate data from the regional climate model REMO were used as input for the Max Planck Institute for Meteorology-Hydrology Model (MPI-HM) to simulate river discharge, runoff, soil moisture and evapotranspiration. The results during the historical period (1971-2000) show that using the bias corrected input yields a better representation of the mean river flow regimes and the 10th and 90th percentiles of river flow at the outlet of the Upper Senegal Basin (USB). The Nash-Sutcliffe efficiency coefficient is 0.92 using the bias corrected input, which demonstrates the ability of the model in simulating river flow. The percent bias of 3.88% indicates a slight overestimation of the river flow by the model using the corrected input. The evaluation demonstrates the ability of the bias correction and its necessity for the simulation of historical river regimes. As for the potential changes of hydrological variables by the end of 21st century (2071-2100), a general decrease of river discharge, runoff, actual evapotranspiration, soil moisture is found under two Representative Concentration Pathways (RCP4.5 and RCP8.5) in all simulations. The decrease is higher under RCP8.5 with uncorrected data in the northern basin. However, there are some localized increases in some parts of the basin (e.g. Guinean Highlands). The projected climate change signal of these above variables has the same spatial pattern and tendency for the uncorrected and bias corrected data although the magnitude of the corrected signal is somewhat lower than that uncorrected. Furthermore, the available water resources are projected to substantially decrease by more than -50% in the majority of the basin (especially in driest and hottest northern basin with RCP8.5 scenario) for all data, except the Guinean highlands where no change is projected. The comparison of simulations driven with uncorrected and bias corrected input reveals that the bias correction does not substantially change the signal of future changes of hydrological variables for both scenarios over the USB even though there are differences in magnitude and deviations in some parts of the basin.

The Influence and the Countermeasures about Water Resources in Northwest of Climate Change

[Objective] The aim was to study the influences and countermeasures of climate changes on the water resources in northwest.[Method] The influences of climate changes on water resources in northwest part were discussed.Considering to the demand of water,corresponding countermeasures were proposed.[Result] Though there were distinct regional differences about the influences of climate changes on water resources in northwest part,the positive influences were larger than negative influences in general;because of large destruction of social factors,the positive effects of climate changes on water resources still can not solve the water shortage problem.In response,influences of climate changes on water resources shall be focused now and then.People’s awareness of saving water shall be improved.Hydraulic project shall be carried out.Suitable agricultural technology shall be applied to establish more sound laws and regulations.The ecological environment of northwest shall be improved and the development of the west part shall be promoted.[Conclusion] The study provided scientific basis for the construction of ecological environment and economic social development in the northwest.

Spatial variability of glacial changes and their effects on water resources in the Chinese Tianshan Mountains during the last five decades

Changes in glaciers in the Chinese Tianshan Mountains have been analyzed previously. However, most previous studies focused on individual glaciers and/or decentralized glacial basins. Moreover, a majority of these studies were published only in Chinese, which limited their usefulness at the international level. With this in mind, the authors reviewed the previous studies to create an overview of glacial changes in the Chinese Tianshan Mountains over the last five decades and discussed the effects of glacial changes on water resources. In response to climate change, glaciers in the Tianshan Mountains are shrinking rapidly and are ca. 20% smaller on average in the past five decades. Overall, the area reduction of glacial basins in the central part of the Chinese Tianshan Mountains is larger than that in the eastern and western parts. The spatial differentiation in glacial changes are caused by both differences in regional climate and in glacial factors. The effects of glacial changes on water resources vary in different river basins due to the differences in glacier distribution, characteristics of glacial change and proportion of the glacier meltwater in river runoff.

Impacts of climate change on glacial water resources and hydrological cycles in the Yangtze River source region,the Qinghai-Tibetan Plateau,China:A Progress Report

The Yangtze River Source Region has an area of 137,704 km2.Its mean annual runoff of 12.52 billion m3,which was recorded by the Chumda Hydrological Station in 1961–2000,accounts for only 0.13 percent of the Yangtze River's total annual streamflow.The extensive rivers,lakes,wetlands,glaciers,snow fields,and permafrost of the Yangtze River Source Region,as well as the region's vast alpine grasslands,play a critical role in storing and regulating the flow of water not only in the upper Yangtze River watershed of Qinghai,Sichuan,the Tibet Autonomous Region (TAR) (Tibet) and Yunnan,but also throughout the entire lower Yangtze River basin.Climate change has been the dominant factor in recent fluctuation in the volume of the Yangtze River Source Region's glacier resources.The Chumda Hydrological Station on the lower Tongtian River has registered a mean annual glacial meltwater of 1.13 billion m3 for the period 1961–2000,makes up 9 percent of the total annual runoff.Glacial meltwater makes up a significant percentage of streamflow in the Yangtze River Source Region,the major rivers of the upper Yangtze River Source Region:the Togto,Dam Chu,Garchu,and Bi Chu (Bu Chu) rivers all originate at large glaciers along the Tanggula Range.Glaciers in the Yangtze River Source Region are typical continental-type glaciers with most glacial meltwater flow occurring June–August;the close correlation between June–August river flows and temperature illustrates the important role of glacial meltwater in feeding rivers.Glaciers in the source region have undergone a long period of rapid ablation beginning in 1993.Examination of flow and temperature data for the 1961–2000 period shows that the annual melting period for glacial ice,snow,and frozen ground in the Yangtze River Source Region now begins earlier because of increasing spring temperatures,resulting in the reduction of summer flood season peak runoffs;meanwhile,increased rates of glacier ablation have resulted in more uneven annual distribution of runoff in the source region.The annual glacial meltwater runoff in the Yangtze River Source Region is projected to increase by 28.5 percent by 2050 over its 1970 value with the projected temperature increase of 2℃ and a precipitation increase of 29 mm.As a critical source of surface water for agriculture on the eastern Qinghai-Tibet Plateau and beyond,the mass retreat of glaciers in the Yangtze River Source Region will have enormous negative impacts on farming and livestock-raising ac-tivities in upper Yangtze River watershed,as well as on the viability of present ecosystems and even socioeconomic development in the upper Yangtze River Basin.

Variation Trends of Hydrology and Water Resources in Yangtze River Delta Region,China and Its Responses to Climate Change

Global warming has become one of important environmental issues, and will alter the spatial distribution of hydrology and water re- sources through accelerating atmospheric and hydrological cycles. Yangtze River Delta region, an economic center in China, has experienced a re- gional temperature increase since the 1960s, forming a heat island, and the warming rate has improved since the 1990s. The characteristics of hy- drology and water resources changed under regional climate warming. Here, the impacts of climate change on hydrology and water resources were discussed from the aspects of precipitation change, sea level rise, seawater invasion and water pollution in Yangtze River Delta region, China.

Exploration of the dynamic water resource carrying capacity of the Keriya River Basin on the southern margin of the Taklimakan Desert,China

The water resource carrying capacity(WRCC)in river basin changes dynamically under climate change,economic development,and technological advancement.Climate change affects hydrological processes and spatial/temporal distribution of water resources;while economic develo-ment and technological advancement can also affect the balance of water resources systems.Under climate change,economic development,and technological advancement,itis of great significance to explore the dynamic behavior of WRCC in river basins.This will help to alleviate water resources security issues and build a sustainable water resources system.This study was carried out to evaluate the dynamic WRCC using the"climate,economics,and technology-control objective inversion mode",which used total water consumption,water-use efficiency,and restrained total pollutant control in the water functional area as boundary conditions.This study was conducted on the Keriya River Basin,a sub-catchment located in southem margin of the Taklimakan Desert.The WRCC in the Keriya River Basin in 2015 was calculated,and the trends in the short term(2020),middle tem(2030),and long term(2050)were predicted.The results revealed that climate change factors have a positive effect on WRCC in the Keriya River Basin,which leads to an increase in total water resources.Economic and technological development exhibits an overall positive effect,while increasing in water consumption and sewage discharge exhibit a negative effect.

Characterisation of Hydrological Drought and Implications for Sustainable Water Resources Management in the Sokoto-Rima River Basin (SRRB), Nigeria

Hydrological drought is usually characterised by water loss over time from both underground and surface supplies. Thus for this study, the assessment of hydrological drought was carried out by employing Cumulative Rainfall/Streamflow Anomaly as preliminary tools for the presence of drought signatures while detailed characterisation was via Streamflow Drought Index (SDI). The results revealed that hydrological drought was observed in all the stations;however, though in general, the stations could be classified as experiencing near normal drought conditions with mild drought signatures. The findings also revealed that the average streamflow deficit volume and durations of the hydrological drought severity were 1.780 Mm3 and 192 months, 1.444 Mm3 and 252 months, 3.148 Mm3 and 252 months, and 0.159 Mm3 and 372 months for Bakolori, Goronyo (pre dam construction era), Goronyo (post dam construction era) and Zobe stations, respectively. The results also revealed the relevance of flow duration curve and analysis of frequency of drought state transition for the development of scenario-based basin water resources management protocol. The coefficient of determination (R2) statistic of the developed regression models indicate that 73.3% and 86.5% variation in streamflow dynamics across the Basin can be explained by climate change variables. However, for sustainable management of water resources in the Basin, it is imperative that characterisation of hydrological drought and monitoring should employ robust indices which use improved monthly precipitation estimates under global warming scenario in addition to ensuring that there is a shift from reactive to proactive approach in order to combat hydrological risk. Hence, a robust framework that finds application both for planning mitigation actions which embody strategic, tactical and emergency components should be designed;to this end, analysis of persistence and recurrence of drought in time and determination of possible recurrent patterns are necessary.

Application of the Bottom-up Method on Risk Evaluation of Climate Change in Water Resources System

Traditional approach to evaluate the impacts of climate change on the water resources systems always begins with downscaling general circulation models( GCMs) and proceeding back to the hydrological model. This approach has some distinct disadvantages: 1) GCM must be downscaled; 2) different GCMs are difficult to be reconciled for a given climate change scenario;3) the uncertainty of GCMs is far from the requirement of the evaluation of climate change impacts. To overcome these limits of the traditional method,a new method termed as "bottom-up"was used for climate risk assessment that linked vulnerability assessment with climate information to assess the risk of climate change impacts on the Quabbin Reservoir,and United States under A2 scenario.The result shows that the risks are around 20% in 2006-2035 and 2036-2055,50% in 2066-2095.

Assessment of water resources in Yarmouk River Basin using geospatial technique during the period 1980–2020

It is common knowledge that Yarmouk River Basin(YRB)is shared between Jordan and Syria.Management of YRB trans-boundary water resources is attracting increasing interest because it is a strategic water resource for the riparian countries.Actually,lack of sharing information regarding hydrological flows and basin’s water management between partners’countries makes it difficult to distinguish between natural and man-made factors affecting the water body.Therefore,this study seeks to address and assess the main on-site changes that exert on YRB.Geospatial technique and arithmetic equations were combined to carry out an assessment of the changes on water resources in YRB.Data,information and field measurements of the basin were aggregated,compiled and presented to determine the extent of changes during the period 1980-2020.Remarkable findings showed that precipitation amount in the basin significantly declined during the period 1980-2020 in particularly after the year 1992.Pumping rate of groundwater was 550 x 103 m3/a,exceeding the basin’s safe yield.Draw down of static groundwater level over time approached the value of-3.2 m/a due to the over abstraction in the aquifer body.Additionally,the evaporation rate reached more than 99%in some regions in the basin.Moreover,the number of private wells has increased from 98 wells in 1980 to 126 wells in 2020,showing the excessive extraction of groundwater.These findings indicate that the study area is subjected to a considerable groundwater depletion in the near future due to extensive abstraction,continuous drilling of illegal wells and decreased annual precipitation under the shadow of the rapid population growth and continuous influx of refugees.Therefore,decision makers-informed scenarios are suggested in the development of water resource portfolios,which involves the combination of management and infrastructural actions that enhance the water productivity of the basin.Further studies are recommended to evaluate the on-site changes on water resources in YRB in collaboration with riparian countries and to establish monitoring system for continuous and accurate measurements of the basin.

Analysis on the Trend of Water Quality in Haihe River Basin from 2005 to 2017

Haihe River is one of the 7 largest rivers in China. The problem of water pollution in Haihe River Basin is serious. The water quality of Haihe River Basin is generally the best in the north and the worst in the south. And the water quality of the Luanhe River is the best, the proportion of I - III is about 60%, and the water quality of the Tuhaimajia River is the worst, the proportion of >V exceeds 60%. According to the trend of water quality change, the improvement of Shandong Province in Tuhaimajia River system is the most obvious, and proportion of >V water decreased from 100% to about 30%.

Impact of Climate Change on Water Resources Management in the Lower Chao Phraya Basin, Thailand

Climate change and associated rising in sea water level have affected the salinity in many rivers around the world. It has an effect on the embouchure adjacent with the sea, which is called the salinity intrusion problem. This study investigated the effects of climate change on sea water level that affects the hydraulic conditions, salinity, water supply and agricultural areas in the lower Chao Phraya River by MIKE 11 model has been used. The study covered the area from Chao Phraya Dam (barrage), Chai Nat Province to the river estuary, Samut Prakan Province. The model was divided into two parts, hydrodynamic module and advection-dispersion model. Calibration of each part was done by adjusting its important coefficients. It was observed that the Manning’s coefficient (n) and coefficient dispersion of mass were in the range of 0.025 - 0.40 and 800 - 1600 m2/s, respectively. The results of comparison between models and observation data revealed order of forecasting error (R2) with the range of 0.76-0.99 for water level and 0.73 - 0.86 for salinity. The RCP 8.5 scenario from IPCC report was simulated. It was found that sea water level rising in was 1.16 m in the year of 2100, and salinity at SamlaePump Station was risen to 0.37 - 0.75 g/l. The value of 0.25 g/l exceeding standard and the pointed tip of salinity was at Koh Rain District, Ayutthaya Province (137 km from Chao Phraya Dam: CPD). For agricultural sectors, the value of 0.20 g/l exceeding standard and the pointed tip of salinity was at Ban Mai District, Ayutthaya Province (123 km from CPD). Results obtained from this study will give the guideline in raw water resources management for water supply and agricultural in Chao Phraya River Basin.