CHAPTER ONE INTRODUCTION
1.1 Background and problem
Fresh water is one of the most valuable assets for any human civilization. The dependency of a country’s overall economy on this resource is due to inevitable demand for water from all sectors of human activities. Dams and reservoirs have served mankind as storage of fresh water for thousands of years. To date, there are over 50000 large dams (structure height higher than 15 m) throughout the world that are used for hydropower, irrigation and drinking purposes (Berga, 2008; Caston et al., 2009). Reservoirs are even more important for communities living in arid and semi-arid regions, because of scarcity of water resources. Pakistan is one of the world’s most arid countries with an average annual rainfall of less than 240 mm. The agricultural sector is regarded as the backbone of Pakistan’s economy. It contributes 25% of the GDP and employs more than 50% of the labour force. Because of the low annual rainfall, Pakistan’s agrarian economy relies on two major reservoirs, the Tarbela Dam on the Indus River and the Mangla Dam on the Jhelum River for irrigation (Archer and Fowler, 2008). Out of its total geographical area of nearly 80 million hectares, the cultivated area is around 22 million hectares. The majority of this area, i.e., 19 million hectares, is covered by irrigation (Agricultural Statistics of Pakistan, 2005 – 2006). Irrigated land supplies more than 90% of agricultural production and most of the food for the country. The agricultural sector is the major user of water and its consumption will continue to dominate water demand.
under SRES scenarios. The gap in literature was found, and to fill that gap this study is much needed. This study aims to answer following major questions: What will be a probable climate of Mangla watershed? How inflow into ManglaReservoir will change because of climate change using GCMs’ under RCPs’ and extreme events? The selection of GCMs’ intensely affects the expected changes of climatological parameters . In this paper, seven GCMs’: BCC-CSM 1.1-m, CCSM4, CSIRO BOM ACCESS1-0, GFDL-CM3, MIROC5, MRI-CGCM3, and UKMO-HadGEM2 under two RCPs’ 4.5 and 8.5 were selected to simulate future discharge using hydrological model SWAT. Description of the study area and data are specified in sections 2 and 3 of this paper. A short description of the hydrological model and the methods employed for the analysis of climate change and streamflow is given in section 3 and 4. Results/discussion and conclusions are given in sections 5 and 6 respectively. The first novelty of this study is the use of a wide range of GCMs’ to cover uncertainties of future climate. The second novelty of this research is the use of new scenarios RCPs’ to cover the uncertainty regarding emission scenarios in all three future time slices. The third novelty is that; this study also quantifies the impact of extreme events on discharge. The fourth novelty is that; the impact of climatic parameters on flows is quantified. This study will be useful to planners and decision makers when planning and applying suitable water management practices for water resources and hydropower to adapt the impacts of climate change including extreme events.
Mismanagement of resources and de-forestation are also major causes of vegetation cover loss. Agricultural practices have increased in the area and land is being cleared for farming during last two decades while no attention towards the management of the watershed is being paid. The change in vegetation cover has resulted in soil erosion and increased sediment ratio into Manglareservoir affecting its capacity and production. Another cause of vegetation loss which is not out of consideration is the changing climate. Unexpected and uncertain precipitation conditions during last two decades have also contributed in loss of vegetation cover.
There are two approaches to analyzing equilibrium reactions: Gibbs energy minimization and Gibbs reaction minimization. In the former, no reaction mechanism is given and only the feedstock and possible products are known. The Gibbs energy is then minimized for the system and species concentrations are determined based on their relative Gibbs free energies. The advantage of this approach is that the knowledge of the specific reactions is not required, which is useful for systems where the mechanisms are either too complex or unknown. The disadvantage is the need for information about the major products; if products are not included in the phase, the concentration will not be calculated. In the second approach, the reactions must be known and Gibbs energy of each reaction calculated and based on these values concentrations of various products are determined. The two approaches for minimizing Gibbs energy are introduced here. In the first part of this study, the major sulfur species present in the system will be identified through Gibbs energy minimization method and in the second part, where the chemical reactivity of sulfur species is studied, the Gibbs reaction minimization method is used in combination with the kinetic study.
out considered 1-stage and 2-stage hedging policies and ra- tioning ratios that were either static (constant all year round) or dynamic (i.e. varying monthly or seasonally). A delta per- turbation approach was used to develop alternative reservoir inflow responses to plausible changes in temperature and precipitation. Subsequent reservoir simulations to test the effectiveness of the various operating policies showed that without hedging, performance of the reservoir (reliability- time- and volume-based and vulnerability) deteriorated sig- nificantly when the reservoir inflow is projected to reduce due to climate change; the opposite occurred when the future is wetter.
The vulnerability was particularly high, reaching over 60 %. However, as hedging was introduced, the vulnera- bility reduced significantly because the modest, deliberate cut-backs during hedging prevented the occurrence of large, single-period water shortages. Indeed, for both the static and dynamic hedging policies, the vulnerability was reduced to below 25 % even for the worst (direst) climate change pro- jections. However, because hedging deliberately fails to meet full demand on occasions, the occurrences of failures in- creased, which led to significant deterioration in the eval- uated time-based reliability. However, since the amount of water shortages for most of these additional shortage peri- ods was low-to-moderate, the overall volumetric reliability of the reservoir was practically unaffected. This is re-assuring since what should matter most in reservoir operation is not the number of failure occasions but the deficit sustained dur- ing such failures. All this confirms that water resources sys- tems have inherent buffering capacity that if well-harnessed through improved operating practices such as the hedging policies developed in this work will offer effective and low- cost mitigation for climate change induced water shortages.
This article conducted an exquisite sequence stratigraphic classification and es- tablished isochronal regional stratigraphic framework. Changxing Formation was divided into four IV order sequences from well-seismic interpretation, which identified the bioclastic shoal reservoirs in this Formation. Under the re- striction of stratigraphic framework, the seismic responding features of intrap- latform shoal and platform margin shoal were concluded by exquisite reservoir calibration. Intraplatform shoal reservoir shows medium-high amplitude and continuous parallel reflection, while platform margin shoal reservoir shows me- dium-weak amplitude, complex wave and hypo continuous parallel reflection. On this basis, attribute analyses and wave impedance inversion were applied to realize the reservoir prediction. The results indicate that the favorable reservoir vertically distributes in SSQ2 and horizontally distributes around Well J43 and Well JZ1, which used to be the platform margin. This application of seismic re- servoir prediction method restricted by sequence stratigraphy is proved to be ef- fective in bioclastic shoal reservoir prediction of Changxing Formation in Jian- nan area and provides useful information for future deployment of the develop- ment wells.
Fish fauna in the Hub reservoir (Table 2) revealed a significant value of that reservoir. The results of present investigation reveal the occurrence of 21 fish species belonging to 7 orders, 9 families. The order Cypriniformes was found dominant (12 species) followed by Perciformes, Osteoglossiformes and Siluriformes (2 species each) and Clupeiformes, Symbranchiformes and Chiocephalioformes (1 species each). The family Cyprinidae was represented by 12 species viz. Catla catla, Chela bacaila, Chela laubuca, Cirrihinus mrigale, Ctenopharyngodon idella, Danio devario, Labeo sindhensis, Labeo diplostomus, Labeo dyocheilus, Labeo rohita, Tor putitora and Cyprinus carpio. Out of these, Cyprinus Carpio and Labeo rohita were found to be most abundant. The family Siluridae was represented by 2 species viz. Wallago attu and Mystus seenghala while Clupeidae was represnented by Gadusia chapra, Gobidae by Glossogobius Gutum and Cichlidae by Oreochromis aureus. Mastacembelidae by Mastacembellus armatus, Notopteridae by 2 species viz. Notopterus notopterus and Notopterus chitala while Ophicephalidae was represented by Ophicephalus sp.
168.90 x 109 m3 [Ministry of water resources and irrigation, 2005]. Releases from AHD account for over 95% of the water resources of Egypt, making the Nile River the effective single source of freshwater for Egyptian agriculture, population, navigation and industry. Studies of climate change impacts on the Nile River show that the basin is extremely sensitive to temperature and precipitation changes [Strzepek and Yates, 2000]. An increase of 10% of average annual precipitation would lead to an average increase in annual flow of 40%. Similarly, a decrease in 10% in precipitation would lead to a reduction of the annual flow with more than 50% [Ministry of water resources and irrigation, 2005]. This paper focuses on the sensitivity of reservoir operation as a result of different climatic scenarios. The intent in this paper is to usereservoir performance measures to evaluate the potential implications of climatic change for reservoir operations
The surface water and sediment samples Ureje Reservoir were analyzed for some physicochemical parameters in relation to land-use patterns in the vicinity of the reservoir located in Ado-Ekiti. The results gave an insight into how activities such as open dumpsites, landfills, farmlands, domestic wastes, construction activities etc impacts on the water environment. Some of the parameters analyzed exceeded the limit set by World Health Organization, thus confirming that these activities rendered the water unfit for drinking and other domestic use except they are treated. It is therefore suggested that most of these activities should be zoned out of the vicinity of the reservoir to improve the environmental quality of life. Also, the observed high level of some of the analyzed parameters, such as total solids, total suspended solids, lead, copper and manganese may pose high degree of health hazards and therefore it is urgent that extensive study be carried out in which more representative samples would be used in order to go beyond the preliminary assessment as reported in this study.
Faming Huang, Kunlong Yin, Tao He, Chao Zhou, Jun Zhang
Subject review The developmental tendencies of cumulative displacement time series associated with reservoir landslides influenced by large water reservoirs must be effectively predicted. However, traditional methods do not encompass the dynamic response relationships between landslide deformation and its influencing factors. Therefore, a new approach based on the exponential smoothing (ES) and multivariate extreme learning machine methods was introduced to reveal the influencing factors of landslide deformation and to forecast landslide displacement values. First, the influencing factors of reservoir landslide deformation were analysed. Second, the ES method was used to predict the trend term displacement and obtain the periodic term displacement by determining the trend term from the cumulative displacement. Next, multivariate influencing factors were analysed to explain the periodic term displacement. Then, an extreme learning machine (ELM) model was established to predict the periodic term displacement based on the multivariable analysis of influencing factors. Finally, cumulative displacement prediction values were obtained by adding the trend and periodic displacement prediction values. The Bazimen and Baishuihe landslides in Three Gorges Reservoir Area (TGRA) were selected as case studies. The proposed ES-multivariate ELM (ES-MELM) model was compared to the ES-univariate ELM (ES-ELM) model. The results show that reservoir landslide deformation is mainly influenced by periodic reservoir water level fluctuations and heavy rainfall. Additionally, the proposed model yields more accurate predictions than the ES-ELM model.
Abstract. The transboundary Mekong River is facing two ongoing changes that are expected to significantly impact its hydrology and the characteristics of its exceptional flood pulse. The rapid economic development of the riparian coun- tries has led to massive plans for hydropower construction, and projected climate change is expected to alter the mon- soon patterns and increase temperature in the basin. The aim of this study is to assess the cumulative impact of these fac- tors on the hydrology of the Mekong within next 20–30 yr. We downscaled the output of five general circulation models (GCMs) that were found to perform well in the Mekong re- gion. For the simulation of reservoir operation, we used an optimisation approach to estimate the operation of multiple reservoirs, including both existing and planned hydropower reservoirs. For the hydrological assessment, we used a dis- tributed hydrological model, VMod, with a grid resolution of 5 km × 5 km. In terms of climate change’s impact on hy- drology, we found a high variation in the discharge results depending on which of the GCMs is used as input. The sim- ulated change in discharge at Kratie (Cambodia) between the baseline (1982–1992) and projected time period (2032– 2042) ranges from − 11 % to + 15 % for the wet season and − 10 % to + 13 % for the dry season. Our analysis also shows that the changes in discharge due to planned reser- voir operations are clearly larger than those simulated due to climate change: 25–160 % higher dry season flows and 5–24 % lower flood peaks in Kratie. The projected cumu- lative impacts follow rather closely the reservoir operation impacts, with an envelope around them induced by the dif- ferent GCMs. Our results thus indicate that within the com-
In this study, the LULCC in the TGRC were investigated from 2000 to 2015, and its impacts on vegetation coverage, LST and climate were analyzed. Our results showed the forest, waterbody, artificial surface, shrub land, and wetland expanded, while the grassland and cultivated land shrank. The large LULLC in the TGRC has resulted in the change of vegetation cover and LST. A total of 93.23% of SINDVI in the TGRC showed an increasing trend from 2000 to 2015, indicating a clear expansion of vegetation coverage in the TGRC. A total of 88.76% of LST in the study area displayed a decreasing trend. Specifically, Chongqing City has the highest LST and the lowest vegetation coverage in the whole area. The LST and SINDVI values varied between the different landuse types. In general, the multiyear SINDVI and LST have significantly negative correlations at most areas of the TGRC. The air temperature, precipitation, and evapotranspiration showed increasing trends from 2000 to 2015 in the TGRC. Similarly to other areas in Southwest China, the LULCC has certain impacts on climate change. In addition, thanks to the environmental protection measures, the forest area increased stably in the TGRC, and it increased more obviously in the eastern part of the TGRC, such as Wushan County, Wuxi County, and Fengjie County, which proved that a better management of landusechanges is crucial for environment change in the TGRC. However, the grassland and cultivated land decreased continuously in Chongqing City and its neighboring regions, Wulong County, Zhong County, and Fengdu County. Clearly, more effective measures are still needed for proper management of landuse in the catchment, particularly in Chongqing City, Wulong County, and Zhong County. Our study showed the advantages of using GEE to analyze the spatiotemporal dynamics of the LULCC, vegetation cover, LST, and climate for a long time-series, and highlighted the importance of environmental protection for the sustainable development in the catchment.
Remote sensing technique for reservoir sedimentation surveys is based on mapping of water-spread areas at the time of satellite over pass. It uses the fact that water-spread area of the reservoir reduces with the sedimentation at different levels. The parameters namely water-spread area and the elevation information are used to calculate the volume of water stored between different levels. These capacity values are then compared with the previously calculated capacity values to find out change in capacity between different levels.
This abnormal results could be explained by different mix- ing modes occurring at the riverine points when the inflow joined the reservoir, which could be represented by the dif- ferences in physical properties like temperature and turbid- ity (Summerfield, 1991). As shown in Fig. 10, the inlets had higher effluxes when the inflow water was warmer and con- tained less suspended sediment than the receiving waterbody. It was suggested that the seasonal variation in effluxes was regulated by both flow mixing modes and reservoir man- agement (Striegl and Michmerhuizen, 1998). Even though in the rainy season intense precipitation could bring plenty of sediment with organic matter, the turbid water might be discharged directly downstream for electricity, because of the relatively small storage capacity of the reservoir. The in- flow water with high sediment concentration was heavier and colder than the reservoir water, thus it plunged into the wa- ter column in the reservoir and became an underflow (hy- perpycnal flow, Fig. 10; Summerfield, 1991). The reservoir surface was less affected by the underflow and maintained a relatively low emission rate (Pacheco et al., 2015) as contin- uous water discharging allowed little time for the mineraliza- tion of OC (Assireu et al., 2011; ¸Sentürk, 1994), in spite of the high flow velocity. However, in the dry season the clean inflow water was lighter and warmer than the reservoir wa-
In the present study, a GA model has been used for optimum reservoir operation. The objective of this study is to minimize the squared deviation of monthly irrigation demand deficit along with squared deviation of mass balance equation. The decision variables used are the release for irrigation demand from the reservoir and initial storage in each month. The constraints used for this optimization are bounds for the releases and reservoir capacity.
Statistical analysis of the color measured data does not show any significant difference between the colors of water from one site to another during the same period. Nevertheless, a significant difference of the color can be seen between the seasons. This situation could be explained by the contribution of the inorganic matter (sand, clay. etc), as well as by suspending organic matter of the reservoir and other mineral matters (iron and manganese) by the surface water currents coming from the catchment during the rainy season.It could also be due to the anthropic activities which are unrolled near the site1 (fishery, the fish sellers, Garbage dumpsand Industrial waste water from SUCCOBE).
Abstract: WEAP (Water Evaluation And Planning) is an integrated water resources planning model developed for more than 25 years by the Stockholm Environment Institute (SEI). In the WEAP model, dam and the water demands (upstream and downstream) are all schematized as an interconnected system ruled by allocation priorities (e.g., dam operation rules, priority for competing demands such as water supply, irrigation, hydropower, environmental flow, water storage in the reservoir). Thwake Reservoir is a multipurpose reservoir for hydropower generation, water supply and irrigation development in Kitui and Makueni Counties. The counties are well known as semi-arid hence the key objective of the study is to estimate the safe yield of the reservoir to enhance effective allocation of the water for different competing demands. Safe yield is based on projected future conditions that include a repeat of the most severe drought of record. Because the definition refers to projected future conditions, safe yield is inherently an estimated characteristic of future conditions that cannot currently be observed or measured. Thus any safe yield is only theoretically available at the time of the estimate. However, the reference to a repeat of the most severe drought of record indicates that past conditions are to be used to project future conditions. In this regard, 1000 years’ synthetic flows were generated using SWAT Model. In the model, 61 years (1952-2012) historical flows were used and the projected flows input into the WEAP model. The monthly reservoir balance for the base scenario and upstream dams development scenario were simulated. The performance of the Thwake Reservoir under different scenarios was assessed. Different sets of scenarios were explored for the Base Case and upstream development dams. These sets were tuned to the operational rules of the Thwake reservoir. Eventually, the dependable yield of the reservoir under different operating rules was estimated for both the base case and the upstream dam development scenarios. Thwake reservoir has an estimated dependable yield when it will be in operation before and after the development of the upstream dams.
Tracer test could be categorized into two main types , i.e. conservative tracer test and partitioning tracer test. In conservative tracer test, the tracer remains in a single phase. Only the volume occupied by that volume is being interrogated via tracer tests. This test provides information relating to its reference phase, i.e. the phase in which it is soluble. In partitioning tracer test, the tracer partition into other phase that are present. The difference between partitioning tracer and conservative tracer could be used to determine the volume of other phases present. Alcohol is one of the partitioning tracers that have been applied in several geothermal fields, such as Matsukawa, Darajat and Kakkonda. In Matsukawa, four types of alcohol (methanol, ethanol, i-propanol, and n-propanol) were injected in order to trace the injectate flow in the reservoir . The tracer return curves were analyzed qualitatively. In Darajat, alcohols were injected along with perfluorocarbons to trace the amount of of steam derived from the injected water . In Kakkonda, a numerical simulation was carried out by incorporating liquid and two-phase tracers using TOUGH2-EOS7R . The phase partitioning behavior of tracer (alcohols) were simplified by assigning Henry’s law constant in the model.
An optimal policy has been developed for release of water from the Sukhi reservoir project for the purpose of irrigation of crops. The releases obtained by Genetic algorithm satisfy completely the downstream irrigation demands for all the four months i.e. June, July, August and September from the year 2004 to 2006 respectively. The considerable amount of water saved in the months of June, July and August for year 2004 to 2006 is 318.25 MCM, 1319.6 MCM and 897.78 respectively. Thus, almost in nine out of twelve months the optimal releases obtained by genetic algorithm, are less than the actual releases, which leads to considerable amount in saving of water.