Environmental Engineering
O. Setiawan; H.Y.S.H. Nugroho; N. Wahyuningrum; D. Auliyani; K.S. Hardjo
Abstract
BACKGROUND AND OBJECTIVES: Micro-hydropower plants are significant contributors of electricity and clean source of renewable energy. A nationwide or large watershed inventory of potential micro hydropower dam sites is lacking, hindering micro-hydropower development. Traditional ground survey approaches ...
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BACKGROUND AND OBJECTIVES: Micro-hydropower plants are significant contributors of electricity and clean source of renewable energy. A nationwide or large watershed inventory of potential micro hydropower dam sites is lacking, hindering micro-hydropower development. Traditional ground survey approaches for locating micro-hydropower dam sites are expensive, time-consuming, laborious, and vulnerable to inconsistency. Geographic information system frameworks are commonly used, and they provide significant value to hydropower evaluation. A suitability approach for dam site identification is important in supporting the optimization of hydropower utilization in the context of watershed management and in eliminating the inconsistency of conventional approaches. The objective of this study was to identify potential sites for micro-hydropower dams on the basis of various parameters by using a suitability modeling approach based on geographic information system.METHODS: The Saddang Watershed was chosen as the study area, it is located in the South Sulawesi and West Sulawesi Provinces of Indonesia, and it is an example of a large watershed. The analytical hierarchy process was used for criterion weighting and to create a dam suitability index map based on the following criteria: geomorphometry, geology, rainfall, soil texture, and land use land cover. The developed dam suitability index map was validated by comparing it with existing dams by using the receiver operating characteristic curve. The identification of potential micro-hydropower dam sites involved overlay and query methods. It considers dam suitability index, proximity from road and settlement, existence of conservation forest, and the potential hydraulic head.FINDINGS: The dam suitability index map with five suitability classes was obtained, with the high and very high suitability indexes extending to 8.7 percent of the study area. These classes were typified by high drainage density, topographic wetness index, stream power index, low vegetation cover, moderate slope, situated on second or higher stream orders, normal temporal distribution of rainfall, and sandy clay loam soil texture with igneous and sedimentary complex rocks. The developed suitability model was sufficiently effective in determining dam suitability index, as indicated by a value greater than 0.9 of the area under the curve. A total of 635 potential dam locations were identified with high and very high suitability indexes, located on first or second stream orders, within a 4,000 m radius of roads and settlements, outside conservation forest areas, and with a potential hydraulic head greater than 20 meter.CONCLUSION: Integrating a dam suitability index map and restriction factors into a geographic information system framework, enabled a robust analysis for identifying potential sites of micro-hydropower dams. The proposed approach is expected to contribute to the advancement of renewable energy initiatives and water resource management within large watersheds. It is also expected to serve as a valuable resource for policymakers involved in the implementation of micro-hydropower projects and watershed management to support the achievement of renewable energy development targets.
Environmental Science
S. Fatnassi; M.B. Almendro Candel; J. Navarro Pedreño; I. Gómez Lucas; M. Hachicha
Abstract
BACKGROUND AND OBJECTIVES: Boron is a micronutrient of high importance, both for plant development and normal growth. The range between boron deficiency and toxicity is very narrow, which makes boron unique among the essential micronutrients. Boron adsorption is one of the most important factors determining ...
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BACKGROUND AND OBJECTIVES: Boron is a micronutrient of high importance, both for plant development and normal growth. The range between boron deficiency and toxicity is very narrow, which makes boron unique among the essential micronutrients. Boron adsorption is one of the most important factors determining the release and fixation of this micronutrient, though its adsorption has not been widely studied in semiarid Tunisian soils. This study aims to improve knowledge of B adsorption process in calcareous salt-affected soils in semiarid areas. It equally focuses on the type of cation (monovalent and divalent) in function of the soil texture and time of shaking. These three latter factors influence boron adsorption, which also influence the availability for plants.METHODS: A study was carried out on boron adsorption at different shaking time intervals (1, 3, 6 and 9 hours) in two soils of different textures in the absence and presence of different background electrolytes solutions (0.02 N CaCl2, 0.02 N MgCl2 , 0.02 N sodium chloride and 0.02 N potassium chloride.FINDINGS: The soil-A (clay loam) adsorbed more boron than soil-B (sandy loam). Boron adsorption was the highest in Soil-A under the presence of potassium chloride, close to the mean values given when using calcium chloride. In Soil-B, it was found with calcium chloride background electrolyte. Minor boron adsorption was observed in both soils when boric acid solution was used without background electrolytes. Adsorbed boron showed significant differences with the shaking time in all treatments used with background electrolytes solutions, except for boron solution treatment without background electrolyte in both soils. As a comparison of divalent and monovalent cations, boron adsorbed content was higher with the solution containing calcium than in sodium chloride solution, due to the fact that calcium carbonate is an important boron adsorbing surface.CONCLUSION: This study reveals that the best conditions for maximum boron adsorption are defined by calcium chloride background electrolyte in this type of soil in a determined shaking time interval of 3 hours. This causes a low rate of boron assimilated by plants, which leads to the decrease of the crop yield and the agricultural production, and subsequently hurt the Tunisian national economy.
Environmental Management
S. Rodelo-Torrente; A.C. Torregroza-Espinosa; M. Moreno Pallares; D. Pinto Osorio; A. Corrales Paternina; A. Echeverría-González
Abstract
BACKGROUND AND OBJECTIVES: Soil is the most important basic natural resource for the support of agricultural production systems. Productivity maintenance in these ecosystems depends on their physicochemical. However, there are no significant studies on the current status of soil fertility and quality ...
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BACKGROUND AND OBJECTIVES: Soil is the most important basic natural resource for the support of agricultural production systems. Productivity maintenance in these ecosystems depends on their physicochemical. However, there are no significant studies on the current status of soil fertility and quality in tropical areas vulnerable to climate change and lacking management practices. The purpose of this study was to assess the physical and chemical properties of the soil to propose guidelines on soil handling and management in tropical areas.METHODS: Data on texture, macronutrients, micronutrients, and cation ratios were collected at 200 farms in the Sucre Department of Northern Colombia. Correlation analysis and principal component analysis were performed on the resulting data set, and a soil quality index was calculated.FINDING: Macronutrients N, P, K, S, Ca, Mg, and Na displayed average values of 21.65 ± 10.65 part per million, 40.35 ± 67.21 part per million, 0.46 ± 0.43 meq/100g, 7.94 ± 28.35 part per million, 15.63 ± 17.30 meq/100 g, 5.63 ± 3.58 meq/100g, 0.19 ± 0.20 meq/100g, respectively. Micronutrients Cu, Fe, Zn, and Mn displayed average values of 2.20 ± 1.66 part per million, 48.05 ± 37.87 part per million, 1.16 ± 1.26 part per million, 14.22 ± 12.24 part per million, respectively. The predominant texture among assessed soils was sandy clay loam. A significant correlation was found between (Ca/Mg) K-Ca/K, (Ca/Mg) K-Mg/K, Fe-Cu, and Ca-cation exchange capacity. The soil quality index of the soils assessed in the Department of Sucre indicates a high level of quality, which is strongly influenced by the indicators S, P, Mn (≥ 0.90) Fe, Zn, Cu, K, Na (≥ 0.80).CONCLUSION: The macronutrients displayed a deficiency of potassium. It is therefore recommended to monitor these soils and apply fertilization plans according to the needs of each assessed soil. Lastly, this study provides relevant information for proposing guidelines for crop improvement.
