As described above, climatechange affects various areas of watershed environment and management. A large watershed having an integrated resource management system such as the Tennessee Valley Authority (TVA) is particularly subject to impacts from climatechange. EPA (1999) summarized the probable impacts of climatechange on watershed hydrology and the water system in the Tennessee areas. Based on EPA (1999), snow accumulation is minimal in Tennessee and runoff would be influenced primarily by higher temperatures, increased evaporation, and precipitation changes. As a result of those factors, hydropower generation could be influenced, navigation disrupted, recreational opportunities degraded, and water availability for water supplies reduced if the runoff decreases. On the other hand, if rainfall and runoff increase in the Tennessee region, then higher streamflows and lake levels could benefit hydropower production, enhance recreational opportunities, and improve water availability for water supplies. Increased rainfall also could increase flooding, which is currently a problem in the steep terrain of eastern Tennessee, along the many unregulated streams throughout the state, and in growing urban areas (EPA, 1999). The future changes of the water quantity and quality caused by the climatechange could influence human activities and the ecosystem over the TVA area.
The credibility of a GCM to predict future climate heavily depends on its ability to reproduce current and past climate; either for a particular region and/or for the globe. A compelling case is the ability of the GCM not only to predict the average climate conditions but also the variability in hydro- climatic variables (Katz, 1992). Regardless of the result, the model can be viewed critically in order to better understand the reasons of good or unrealistic predictions. In weather prediction, forecasts are produced on a regular basis and verification against what actually happens can quickly be performed. In contrast, climate predictions are designed for much longer periods (e.g. many decades) and for conditions without precise past analogues. One direct way to gain confidence about the performance a model for such predictions is to compare its predictions with known historical measurements or indirect evidence when records are missing. Results of climate model simulations are needed in impact analysis but for simulation to be considered reliable, the outcomes should fulfill some quality criteria (Christensen et al., 2007). Simulation of climate for the periods for which data are available and to acceptable accuracy is one of the most important qualities of a reliable climate model. The difficulty, here, is in determining what is acceptable or reasonable. Statistical metrics can be used to define the quality criteria and acceptability for a reasonable simulation. Although the field of statistics has played a relatively minor role in the development of GCM concept, its importance in validating the models is indispensable.
lakes are extremely sensitive to the balance of inflows and evaporative losses. Even small changes in climate can produce large changes in lake levels and salinity (Laird et al. 1996). Other effects of increased temperature on lakes could include higher thermal stress for cold-water fish, higher trophic states leading to increased productivity and lower dissolved oxygen, degraded waterquality and increased summer anoxia. Decreases in lake levels coupled with decreased flows from runoff and groundwater may exacerbate temperature increases and loss of thermal refugia and dissolved oxygen. Increased net evaporation may increase salinity of lakes. Hostetler and Small (1999) also note that climate variability may amplify or offset changes in the mean state under climate changes and may ultimately be more important that changes in average conditions. Some non-linear or threshold events may also occur, such as a fall in lake level that cuts off outflows or separates a lake into two isolated parts. Work is needed to identify threatened lakes in California and projected impacts of such events on downstream flows and groundwater recharge.
urbanization. To reduce non-point source pollution and improve waterquality, land management practices such as conservation tillage and optimum irrigation are also routinely used [Barrington et al., 2013; Delgado et al., 2013]. BMPs and better fertilizer application management is needed to control NPs of TN, TP. As compared to employ individual crop and tillage management practices and structural controls, combinations of crop, tillage and structural control scenarios revealed to have more potential to reduce sediment yield [Chen et al., 2012; Hong et al., 2012].The interaction of land use and climatechange varies greatly in time and in space, as fluxes of water within a catchment move both vertically (e.g. evapotranspiration) and laterally (through soils, hill slopes, aquifers and rivers). Thus, as water moves through the catchment any impacts of the climatechange and land use can be transmitted through the catchment [Falkenmark, 2003]. So the assessment of LULC and climatechange usually includes evaluation of spatial patterns of hydrological consequences to different LULC maps, temperature, precipitation, comparison of simulated hydrological components to LULC and climate changes at the basin scale, and examination of temporal responses in channel discharge with changes in LULC and climate [Stohlgren et al., 1998; Nie et al., 2011].
Much of the north of England relies on surface waterresources because the geology of the north-west results in groundwater storage potential of only 15% (Fowler et al., 2003; Walker, 1998). Therefore, short-term summer drought, as well as longer droughts such as that in 199596, can have an extremely detrimental effect on water supplies (Marsh, 1996) in the Integrated Resource Zone (IRZ) of United Utilities. This network of impounding reservoirs, river and lake abstractions, inter-river transfers and groundwater abstractions is linked to the major urban centres through major aqueducts (Walker, 1998). Rainfall, mainly from weather systems in the westerly quadrant, leads to a seasonal flow regime, with the runoff largest in winter and spring and least in summer. During the 199596 drought, the most severe in the historic record, the 18-month rainfall of only 56% of the long-term average caused reservoirs to be at their lowest historic levels in the spring of 1996 (Walker, 1998). Despite the success of management in avoiding severe restrictions on water supply throughout the 1995 96 drought, the need to quantify the likely effects of climatechange on the IRZ was highlighted as a priority.
The impacts of climatechange on waterresources are potentially large and could result from increases in temperature and from changes in mean annual values and the variability of precipitation. However, our ability to predict climatechangeimpacts on waterresources and plan for adaptation and amelioration is hindered by the lack of good predictions of future climate at regional scales and a lack of fundamental understanding of many of the effects of climate variability on the physical, chemical, and biological characteristics of waterresources. Several areas of future research are critical for improving our understanding of and our ability to predict effects of climatechange on waterresources. These include the development of better regional climate models, studies of relationships between climate variability and physiological and ecosystem processes, initiation of integrated assessment of impacts, and analyses that define viable response options for future changes in climate. Many water bodies are highly managed and changes in waterresources management (infrastructure, operations, and administration) can potentially ameliorate some of the impacts of climatechange. Adaptation will be necessary in many cases, however, and it is only through an improved understanding of climate and its effects on waterresources that we can begin to plan the adaptation strategies that will be needed.
SWAT model was successfully applied for the Al-Adhaim basin at monthly time steps. The model was calibrated and validated at Injana hydrological station. The calibration and validation results showed good performance of the model in simulating hydrologi- cal processes. The calibrated model was used to identify the impacts of climatechange on blue and green water over last three decades. It was also used to project blue and green water and deep aquifer recharge for near future (2046-2064) and far future (2080-2100) under three emission scenarios (A2, A1B, B1) using six GCMs. All models under three emission scenarios predicted that whole basin will be extremely dry in near and far future. The results of this study may enable decision makers to find a suitable waterresources management and crop production for future.
Conclusion: Anthropogenic activities have contributed to changing patterns of extreme weather across the globe, ranging from longer and hotter heat waves to heavier and erratic rains. These events are all anticipated to be as a result of climatechange. (Gervais.F.2014). While climate variability and change continue to impact as more extreme events are anticipated to occur as result of increased temperatures and change in rainfall intensities, both extremes will have an impact on the river flows as erratic and heavy rains will lead to more floods, soil erosion among others and a reduction results into prolonged droughts/ water scarcity. As more understanding of how climatechange will affect extreme weather is still developing, it’s more likely that extreme weather may be affected even more than anticipated as the extremes are on the rise an indication that they will continue both in predictable and unpredictable ways.
To this end, two classes of long-range water-manage- ment decisions are discussed: general system evaluations and flood-risk evaluations. For the first class, a generalized planning framework is introduced (section 3.1) to describe how long- range evaluations are set up by assumptions for possible future supplies, demands, and operating constraints. The role of climate information in establishing these assumptions is then discussed, including the traditional use of instrumental records and the potential use of expanded climate information. Expanded climate information might include a mix of paleoclimatic evidence of hydroclimatic conditions, stochastic modeling to augment sequence possibilities, and (or) climate-projection informa- tion to define climate possibilities during the future planning horizon. For the second class, the probabilistic and deterministic approaches for flood-risk evaluation are discussed (section 3.2). The focus is placed on the underlying climate assumptions and the challenges introduced by a changing climate while conduct- ing such evaluations. Thereafter, several recent Reclamation and USACE studies featuring the expanded use of climate informa- tion are summarized (section 3.3) to highlight common themes and implications for planning processes. Finally, a summary discussion is offered on how these traditional and potential appli- cations of climate information call attention to system portrayal paradigms, particularly in adaptation planning, and research avenues to advance long-range decisionmaking capabilities.
First and foremost, thanks to God Almighty for the guidance and aid in giving me the strength to finish my project “Potential Study of Bera LakeWaterQuality for Alternative Source if Water Supply” to complete this thesis. A great appreciation thanks to my project supervisor, Dr Mir Sujaul Islam for the guidance, advices and knowledge throughout this study. He had taken a lot effort to give opinion and comment about my project.
Rising global temperatures have threatened the operating conditions of Batang Padang hydropower reservoir system, Malaysia. It is therefore crucial to analyze how such changes in temperature and precipitation will affect water availability in the reservoir in the coming decades. Thus, to predict future climate data, including daily precipitation, and minimum and maximum temperature, a statistical weather generator (LARS-WG) is used as a downscaling model. Observed climate data (1984-2012) were employed to calibrate and validate the model, and to predict future climate data based on SRES A1B, A2, and B1 scenarios simulated by the General Circulation Model’s (GCMs) outputs in 50 years. The results show that minimum and maximum temperatures will increase around 0.3-0.7 ºC. Moreover, it is expected that precipitation will be lower in most months. These parameters greatly influence water availability and elevation in the reservoir, which are key factors in hydropower generation potential. In the absence of a suitable strategy for the operation of the hydropower reservoir, which does not consider the effects of climatechange, this research could help managers to modify their operation strategy and mitigate such effects.
Agriculture also contributes to and experienc- es the effects of climatechange. All agricultural crops require appropriate soils, water, heat and sunlight so that they can grow optimally. The in- crease in air temperature has already affected the length of the growing season in a large area in Eu- rope. Both flowering and harvesting cereal crops occur a few days earlier and it is expected that these changes will progress in many regions. The land designated for agricultural crops is at risk. It may be dislodged or disappear completely, lead- ing to economic problems in countries, includ- ing lack of food. The existing extreme weather phenomena have a direct or indirect impact on a significant increase in the risk of failed harvests, also on the soil, causing a decrease in the organic matter content, which is the main factor ensuring its fertility. The direct impact is mainly a change in the atmospheric conditions for the productivity of crops, including sums of atmospheric precipi- tation, changes in thermal conditions, frequency and intensity of extreme phenomena. The 2004 European Environment Agency report states that compared to the 1990s, a two-fold increase in the number of climate disasters occurred, and the value of losses caused by them exceeded in 2005 the amount of up to 200 billion dollars, while at the turn of the 20th and 21st century alone, they reached several billion dollars a year [Trzpil, 2008, Tubiello et al., 2007, Olsen et al., 2011].
approach to simulate water systems and orient management policies, is applied as well as certain mathematical analyses and statistical methods. Thus, the study visualizes and analyzes the incidence of potentialclimatechange on the hydroelectric sector, finding the degree of vulnerability for this or any other sector that relies on water as a source, and offers tools, strategies and criteria for the planning and orientation of projections in the different productive sectors. The results predict increases in maximum, mean and minimum temperatures, for example, the maximum temperature before the end of the century could rise from 1.3° to 2.5°C in scenario A2 and from 0.9° to 1.7°C in B2; an increase in precipitation is estimated up to approximately 30.4% in A2 and 27.9% in B2. The number of extreme events forecast is found over previously determined thresholds; an estimation is made of the water balance and the relation of the above variables to the Sinú River inflow to the Urrá 1 dam and the generation of hydroelectric energy. Changes in the generation of hydroelectric energy vary from 0.6 to -35.2% for the period 2010 to 2039, reduction in the Sinú River inflow to the dam in a range of -2.3 to -34.9% and a drop in the stored volume in the dam of -0.9 to -29.4 percent in relation to the maximum storage capacity (MSC), according to the analyzed scenario.
Lakes in Malaysia, natural or artificial, have multiple functions. Almost 90 percent of the nation’s water supply comes from the lakes and reservoirs. Lakes and reservoirs serves as the source of water for domestic, industrial and agriculture, hydroelectric power generation, flood mitigation, navigation and recreation. They are also home to a variety of biological species and freshwater fish industry like Kenyir Lake. Kenyir Lake luxurious forest is located in the district of Hulu Terengganu and the world oldest tropical rain-forest. The lake is known as a unique tourist destination for her beautiful scenario of tropical forest and widely known for its valuable flora and fauna species. It is believed that the area is the habitat of more than 8000 species of flowers, 2500 species of plants and trees, 8000 species of orchids, 370 species of birds and 300 species of fresh water fish. This study involves 21 main sam- pling stations that has been determined using DGPS which located around the Kenyir Lake Basin representing the length of the Kenyir Lake (Table 3 and Figure 6). The fieldwork was performed on wet season and dry season: the first sampling (Sampling 1) was carried out in April 2017 (Dry season) and the second sampling (Sampling 2) was carried out in December 2016 (Wet season).
Received: 26 March 2019; Accepted: 18 April 2019; Published: 24 April 2019 Abstract: This article illustrates the impact of potential future climate scenarios on water quantity in time and space for an East African floodplain catchment surrounded by mountainous areas. In East Africa, agricultural intensification is shifting from upland cultivation into the wetlands due to year-round water availability and fertile soils. These advantageous agricultural conditions might be hampered through climatechangeimpacts. Additionally, water-related risks, like droughts and flooding events, are likely to increase. Hence, this study investigates future climate patterns and their impact on waterresources in one production cluster in Tanzania. To account for these changes, a regional climate model ensemble of the Coordinated Regional Downscaling Experiment (CORDEX) Africa project was analyzed to investigate changes in climatic patterns until 2060, according to the RCP4.5 (representative concentration pathways) and RCP8.5 scenarios. The semi-distributed Soil and Water Assessment Tool (SWAT) was utilized to analyze the impacts on waterresources according to all scenarios. Modeling results indicate increasing temperatures, especially in the hot dry season, intensifying the distinctive features of the dry and rainy season. This consequently aggravates hydrological extremes, such as more-pronounced flooding and decreasing low flows. Overall, annual averages of water yield and surface runoff increase up to 61.6% and 67.8%, respectively, within the bias-corrected scenario simulations, compared to the historical simulations. However, changes in precipitation among the analyzed scenarios vary between −8.3% and +22.5% of the annual averages. Hydrological modeling results also show heterogeneous spatial patterns inside the catchment. These spatio-temporal patterns indicate the possibility of an aggravation for severe floods in wet seasons, as well as an increasing drought risk in dry seasons across the scenario simulations. Apart from that, the discharge peak, which is crucial for the flood recession agriculture in the floodplain, is likely to shift from April to May from the 2020s onwards.
precipitation is increasing by 1.3513mm/year. However, the precipitation pattern is changing over the years with the notable increase of high precipitation, causing to increase the river water discharge and flood leading to the huge loss of properties including land, stored grains and lives of people. Lack of rainfall in the cropping season lead to excessive extraction of ground water for irrigation. The cost of ground water extraction is also high, which the small farmers can not afford and leave the land barren. The coping practices noted in region are constructing embankments; planted different plants like bamboo (Bambusa vulgaris), Sugarcane (Saccharum officinarum), Typha (Typha latifolia) etc.; storing grains in upper part of the house; extracting ground water for irrigation; changing crops (vegetables instead of paddy and wheat); changing the species of crops and increased use of fertilizers and pesticides.
During the last few decades, Iraq faced extreme climate events represented as severe drought recorded between 2007 and 2009 followed by heavy rainfall oc- curred in a few months in southern parts of Iraq with almost two times of nor- mal records . Admo et al.  applied six General Circulation Models (GCMs) in SWAT model to investigate the impact of climatechange on waterresources of Tigris River under three scenarios of future climatechange which are A2, A1B and B1 of highest, medium and lowest. They summarized that the precipitation will decrease in overall five tributaries (Khabour, Greater Zab, Lesser Zab, Adhaim and Diyala) of Tigris River Basin, at the same time meaning the surface and ground water will decrease as the reflection of increasing temperature and decreasing in precipitation. It is recommended to investigat the impact of climatechange for each tributary alone. Abbas et al.  used SWAT to quantify the impact of cli- mate change in Lesser Zab River, they indicated that the blue water will decrease by the range from 8% to 43% in 2046. In addition, the green water will decrease by 5% to 24% in 2046 under A1B scenario. Abbas et al.  explored the rela- tionship between climatechange and its impact on waterresources of Tigris River tributaries using SWAT model. The results showed that the precipitation will be reduced by 12.6% and 21% in the period from 2049 to 2069 and distant the period from 2080 to 2099 futures, respectively under RCP8.5. Consequently, the blue water will decreases by 22.6% and 40% under RCP8.5, 25.8% and 46% under RCP4.5, and 34.4% and 31% under RCP2.6 during the periods from 2049 to 2069 and 2080 to 2099, respectively. Ali et al.  used Sen’s slope and the Mann-Kendall test to assess the streamflow trend of Lesser Zab River for the pe- riod 1964 to 2013. They indicated that stream flow would decrease by 5.09 m 3 /month in April and 1.06 m 3 /month in November with annual rate of de-
The peaceful settlement of relations connected with management and water consumption issues within and beyond the frontiers of the country is an important guarantee of the region stability. Study and estimation of water objects located in the vicinity of frontiers by means of hydrological, hydro-chemical and hydro-biological methods is an immediate objective of many international projects. The said problem is urgent in Georgia as well . Georgia is an active participant of joint and regular monitoring, information exchange meetings with its neighbor countries (Azerbaijan and Armenia) with a view of common protection and use of trans-boundary water objects (Mtkvari /Kura/), Alazani, Iori, Khrami, Debeda, etc.). Usually, in the trans-governmental basins the available waterresources and the territories corresponding to them are unequally distributed, that quite often is a reason for conflicts among the states.