Water Reservoir Capacity Research Articles

Charvak reservoir modeling based on geoinformation systems

The article describes the Charvak reservoir morphological map development, created using the softs capable of processing, analyzing, and visualizing high-resolution satellite geodata. The study determined the amount of useful volume change during the reservoir's operation. The map was designed to be interactive and processed in real time using GoogleEarth and ArchGIS analytical tools. The study aims to improve effective monitoring of the changes in water reservoir capacity and forecasting the further operational period of the reservoir. The research demonstrates the potential of geoinformation technologies to improve water resources management.

Optimal sizing and energy management of a stand-alone photovoltaic/pumped storage hydropower/battery hybrid system using Genetic Algorithm for reducing cost and increasing reliability

In this paper, a genetic algorithm is applied to optimize the sizing of an autonomous renewable energy multi-source system for reliable and economical supply of energy. The multi-source system is composed of a photovoltaic generator, a pumped storage hydropower system and a battery. The system will power public lighting and operate a garden fountain in the Botanical Garden, located in the Alexandre Aibéo Park in Covilhã (Portugal). Solar irradiance is initially simulated for a reference photovoltaic capacity (25 kWp) over one year by the PVsyst software for the city of Covilhã. Two objective functions are used for sizing optimization: the loss of power supply probability (LPSP) and the levelized cost of energy (LCE). The LCE takes into account the capital cost, the replacement cost and the cost of operation and maintenance. The genetic algorithm is used to determine the best configuration of the different subsystems (photovoltaic generator capacity, upper water reservoir capacity and battery capacity). The originality of this work lies in the combination of two storage elements with different dynamics, the introduction of an adapted energy management strategy (EMS) allowing to manage energy flows between the different subsystems and to control the process of charging/ discharging storage elements, and multi-objective optimization (considering technical and economic criteria) of the sizing of the autonomous photovoltaic/pumped storage hydropower/ battery hybrid system using genetic algorithm.

ELECTRICITY PRICE FUNDAMENTALS IN HYDROTHERMAL POWER GENERATION MARKETS USING MACHINE LEARNING AND QUANTILE REGRESSION ANALYSIS

A hydrothermal power generation market is characterized by a strong dependence on water reservoir capacity and fossil fuel sources, which causes differences in generation marginal costs and high variability of the electricity spot price. Therefore, this study proposes an empirical approach to identify the price determinants and their effects on price dynamics. This paper presents two methodologies: a machine learning approach and a quantile regression analysis. The first method is used to validate the price determinants through a prediction process, and the second, the quantile regression, to identify the non-linear effects. The most important factors observed are total market demand, water reservoirs capacity for generation, and fossil fuel consumption. The results offer a new perspective about the market structure and spot price volatility.Keywords: electricity prices; hydrothermal power generation markets; machine learning; quantile regression; Gaussian process regression.JEL Classifications: C22, Q41, Q43, Q47DOI: https://doi.org/10.32479/ijeep.11346

Predictive Calculations of the Bulk Water Reservoir Capacity Using a Geographic Information System

The Tuyamuyun hydro-complex on the Amu Darya River, consisting of one in-channel and three off-channel basins with a design volume of 7.8 billion m3, was intended to improve the supply of irrigation water and electricity to the Khorezm region and the Republic of Karakalpakstan and to control the catastrophic floods in the lower reaches; it was put into operation in 1984. The water reservoir complex is in joint use by the Republics of Uzbekistan and Turkmenistan. Numerous measurements showed that the useful volume of the reservoir due to siltation decreased from 2.34 billion m3 to 770 million m3, i.e. by 67%. To partially compensate for the lost capacity, it was proposed to build-up the protective levees and to erect the new dams, where the topography of the area allowed. Using the GIS, the predictive volumes to increase the capacity of the Channel water reservoir have been proposed, depending on the water level in the reservoir, which between the marks ▽130.0 and ▽131.5 amounted to 527.3 million m3. The necessity was shown to increase the height of the following protective dams: No. 1 ▽134.5, No. 2 ▽134.8, No3 ▽136.7, No. 4 ▽134.4, No. 5 ▽136.4. No. 6 ▽137.9, No. 8 ▽138.6, No. 9 ▽135 and land dam 134.8.

Soil water reservoir properties of green belts in the central urban area of Shanghai, China

Taking the typical parks and public green belts in the central urban area of Shanghai for examples, water reservoir storage of soils of different types and influencing factors were investigated based on field surveys. The results showed that the total reservoir capacity of soils of the green belts in the central urban area of Shanghai was relatively low. However, the whole green belts still accumulated a large amount of water, which reached up to 1.88×107 m3. The existing water volume was 75.7% of the total reservoir capacity, while the remaining water storage was relatively low. The detention capacity and the effective storage of green belts were 31.6% and 27.2%, respectively. The dead storage was 44.5 %. Moreover, some difference existed in the water reservoirs for different vegetation types. The total water reservoir capacity of soils and the remaining water-storage space of the tree and brush lands were obviously higher than those of the grass lands. The water-detention capacity and the effective storage of the brush lands were remarkably higher than those of the tree and grass lands, but there was no remarkable difference among various vegetation types for both the existing water volume and the dead water storage. Thus, reducing soil compaction, increasing organic-matter content, improving physical properties and optimizing plant allocation of green belts would improve the water reservoir capacity effectively for the urban green belt soils.

Capacities of soil water reservoirs and their better regression models by combining “merged groups PCA” in Chongqing, China

Soil water resource, together with the surface and sub-surface water resource, is essential to the regional water balance and world water cycle. A total of 90 soil samples were collected from 30 different soil profiles of dry fields throughout Chongqing, China randomly to show how soil could be a crucial part of water resources by discussing their five types of calculated soil water reservoir capacities, namely the total soil water reservoir capacity (mm) (TC), soil water storage capacity (mm) (SC), unavailable soil water reservoir capacity (mm) (UC), available soil water reservoir capacity (mm) (AC), and soil dead water storage capacity (mm) (DC) in certain layer, respectively. Overall, the total soil water reservoir capacity in 0–40cm was about 209mm, of which 70mm belonged to available soil water reservoir capacity. Not all the five types of soil water reservoir capacities had significant correlations between each other. Soil structure, especially the size and quantity of soil pore was mainly determined by soil particle composition (clay, silt, and sand content). The more sand and less clay led to the more soil macropores, which provided room for soil water. Thus, clay, silt, and sand content jointly produced profound influence on soil water reservoir capacities. Nevertheless, specific water capacity and topographic factors displayed weak correlations to soil water reservoir capacities, which required further research works. Ultimately, the better regression models were achieved by multiple regression analysis coupled with “merged groups PCA” than by multiple regression analysis with “all variables PCA”. UC, SC, TC and DC could be well simulated (mostly R2>0.70; P<0.05) through normal multiple regression analysis using original variables as well as multiple regression analysis with “merged groups PCA”. Only regression models of TC and DC were highly significant (mostly R2>0.70; P<0.05) through “all variables PCA” method. And there were poor coefficients of determination (R2) for AC (mostly R2<0.40; P<0.05) by all the three regression methods.

Case study: Energy savings for a deep-mine water reticulation system

In deep level mining, water reticulation systems are one of the major consumers of electricity. The refrigeration plants, together with the underground water supply and dewatering systems are integrated to form one complete water reticulation system. This integrated water reticulation system extracts hot water from the mine, cools it down and returns the cold water to the various underground mining levels. As much as 42% of the total energy consumption on a typical deep level gold mine can be ascribed to the water reticulation system. Reducing the overall water demand and therefore electricity costs will depend on climatic conditions, operating strategy, water reservoir capacity, and electricity tariff rates. In this paper, a method is presented to determine the optimum water reticulation strategy for different electricity tariffs. This model minimises the total operating cost of the water reticulation system by a trade-off between the cost involved in providing effective pump control and the savings achieved under a specified electricity tariff. A case study of a typical deep mining operation shows that a reduction of 65% during peak demand and 2% overall electricity reduction is possible by adopting this new control strategy. The corresponding savings in operating cost is 13%. Techniques were developed to integrate, simulate, optimise and control all components of the water reticulation system. This will allow for a quick assessment of the effect of individual components on the complete system. By integrating all these components into a single system, the operation of each component can be assessed and optimally controlled without adversely affecting other operations of the system.

Geostatistical approach for the assessment of the water reservoir capacity in arid regions: a case study of the Akdarya reservoir, Uzbekistan

The paper presents the results of a new geostatistical approach to generate bathymetric surface models from point measurement converted into continuous contour surfaces of reservoir bottoms in Uzbekistan. Sedimentation of reservoirs raises engineering, environmental and economical issues for the communities around the world in areas affected by a strong water deficit. Because of Uzbekistan’s arid climatic conditions, and uneven spatial and temporal water resources distribution, responsive and innovative water availability assessment surveys of all major water reservoirs are required. Bathymetric surveying is a traditional method that is carried out for the estimation of reservoir volumes and surface areas of the corresponding reservoir stages in order to assess the water availability. Volume and surface area differences derived from multiple surveys of a reservoir provide storage loss estimates over time due to sedimentation. However, two main factors, such as intensive field data measurement and post data-processing, often limit the frequency of these surveys. Alternatively, innovative depth measurement technologies coupled with contouring and surface mapping programs provide automated reservoir volume and surface area calculations. This significantly reduces time, workload and financial burdens for reservoir sedimentation projects. This research proposes the use of geostatistical approach to assess the reservoir sedimentation in the Akdarya reservoir of Uzbekistan. The geostatistical approach includes (semi-) variogram analysis and interpolation (kriging and simulations—turning bands) techniques predicting values at unsampled locations for generating digital bathymetric surface models of reservoir bottom conditions in order to calculate the volume and surface area at a given water elevation. The simulation enables to have range of reservoir volumes and surface areas with the same probability, in comparison to the kriging and traditional methods. This gives a real estimation of the resource availability for water operators to manage natural resources and hydraulic infrastructure in a sustainable manner.

Characterization of Physiological and Biochemical Factors Associated with Postharvest Water Loss in Ripe Pepper Fruit during Storage

Fruit of pepper (Capsicum annuum L.) is hollow by nature, which limits its water reservoir capacity, and as such, small amounts of water loss result in loss of freshness and firmness, which reduce fruit quality, shelf life, and market value. In order to understand the basis for water loss from fruit, 10 pepper accessions with wide variation in water loss rate were used to study physiological and biochemical factors associated with postharvest water loss in ripe pepper fruit during storage. Postharvest water loss rate in ripe pepper fruit stored at 20 °C, and 85% relative humidity, was found to be associated with cell membrane ion leakage, lipoxygenase activity, and total cuticular wax amount. Total cuticular wax amounts were highest in the high-water-loss pepper fruit, and lowest in the low-water-loss fruit. However, total cuticle amount (isolated enzymatically and quantified gravimetrically), total cutin monomer amount, and the amount of individual cutin monomer and wax constituents (determined using gas chromatography mass spectrometry) indicated no direct association with postharvest water loss rates. Fruit fresh weight, pericarp weight, pericarp surface area, pericarp thickness, initial water content, and dry matter were highly associated with each other, but less so with water loss rate. Fruit of accessions displaying high fruit water loss rate matured and ripened earlier than fruit of accessions displaying low-water-loss rate. Cell membrane ion leakage and lipoxygenase activity were higher after storage than immediately after harvest. Pepper fruit total cuticle wax amount, lipoxygenase activity, and cell membrane ion leakage were directly related to postharvest water loss rate in pepper fruit during storage.

Energy Use in Hydrocooling Stone Fruit

Energy use per unit of product cooled is reported for two commercial hydrocoolers. Energy use by major components is listed. Heat input measurements and operational data are used to evaluate possible energy conservation methods such as minimizing external heat gain, operating coolers at maximum capacity, minimizing water flow, and reducing water reservoir capacity.