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Exploitation of Satellite Data for the Mapping of Areas at Risk of Flooding in Grand-Bassam (Côte d’Ivoire)

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Advances in Remote Sensing 2020年第4期9卷 117-126页

作者： kouakou hervé kouassi Zilé Alex Kouadio Arthur Brice Konan-Waidhet Affessi Christian Serge Affessi kouakou Lazare kouassi Laboratory of Science and Technology of Environment Jean Lorougnon Guédé University Daloa Cote d’Ivoire

In order to better identify spatially the areas at risk of flooding for the riparian populations of Grand-Bassam during strong floods, a study aimed at developing hazard and vulnerability maps from RADAR Sentinel-1 and optical images Sentinel-2 has been put in place. The flood hazard study highlighted the flooded areas in Grand-Bassam. These areas represent 747.7 ha, or 1.02% of the total surface. The vulnerability map produced using the maximum likelihood method identified eight (8) land use classes. These are the classes Water, Dense forest, Secondary forest, Swamp forest, Industrial crops, Food crops, Habitats and bare soils. It made it possible to highlight the socio-economic interests of Grand-Bassam. The flood risk map developed from the intersection of the themes of the vulnerability map and that of the hazard has enabled the recognition of risk areas which are located near the source of the risk (Comoé River) and at low altitudes. These are Moossou, Petit Paris, Quartier Phare and Quartier France.

关键词： Remote Sensing Hazard Vulnerability Flood Risk Grand-Bassam

Land Use Dynamics in the Department of Séguéla, Northwestern Côte D’Ivoire

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Advances in Remote Sensing 2022年第3期12卷 63-79页

作者： Arthur Brice Konan-Waidhet kouakou hervé kouassi Kouamé Elyass Kanga Laboratory of Science and Technology of Environment Jean Lorougnon Guédé University Daloa C&#244 te d’Ivoire

Land use monitoring occupies a very important place in the analysis of the dynamics of the earth system. It helps to understand the organization and helps to provide relevant elements for the establishment of diagnoses and the development of environmental forecasts. The objective of this study is to follow the evolution of the agricultural landscape in the department of Séguéla from 1988 to 2020 and to make a prediction for 2050, in order to manage the spaces reasonably. The methodology adopted is based on the one hand on the processing of satellite images for the analysis of land cover and on the other hand on predictive modeling (LCM model) by 2050. The results obtained show that the land use maps produced after processing the satellite images made it possible to highlight the dynamics of the agricultural landscape in this part of the Worodougou region. During the period 1988 to 2020, we witness an increase in the area of cultivated territory as well as a slight reduction in wooded savannas which are largely made up of perennial crops (cashew trees, cocoa trees, coffee trees, etc.). These two aforementioned classes have respective annual rates of change of 2.42% and −0.44%. A scenario modeling land cover changes in 2050 with an overall accuracy of 80.35% revealed a continued growth of crops and fallows to the detriment of natural forests and wooded savannas.

关键词： Satellite Images Land Use LCM Model Land Cover Change Séguéla

Simulation of the Dynamics of Land Cover and Land Use in the Lobo River Watershed Upstream of Nibéhibé(Center-West of Côte d’Ivoire)

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Journal of Geographic Information System 2020年第5期12卷 519-530页

作者： kouakou hervé kouassi Arthur Brice Konan-Waidhet Affoué Berth Yao Berenger Koffi Ettibou Damase Kadjo Laboratory of Science and Technology of Environment Jean Lorougnon Guédé University Daloa C&#244 te d’Ivoire

From medium-resolution satellite images (Landsat TM, ETM+ and OLI), the spatial dynamics of land cover and land use are highlighted. The objective of this study is to quantify the evolution of land use in the watershed of the Lobo River upstream of Nibéhibé between 1986 and 2019 in order to analyze the impacts of human activities on the landscape. The study method was based, on the one hand, on the processing of satellite images, for the analysis of the dynamics of land use and, on the other hand, on the CA-Markov model, for the prediction of land use by 2050. It emerged from this study that the land use maps produced made it possible to highlight the spatio-temporal dynamics of land use on the basin. For the period from 1986 to 2019, there is a decrease in the area of forests in favor of built-bare ground and crops and fallows. A land use scenario for the years 2019 and 2050 was simulated with an accuracy of 87.11%. The regressive trend in forests seems to continue in the future with current land use practices.

关键词： Satellite Image Land Cover and Land Use Space-Time Modeling Lobo

Mapping of Pollution Risk of Surface Waters by Runoff from Watershed: Case of Aghien Lagoon (South of Côte d’Ivoire)

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Journal of Water Resource and Protection 2015年第17期7卷 1457-1466页

作者： Konan Jean-Pierre Koffi Yao Alexis N’Go Diakaria Kone kouakou hervé kouassi Savané Issiaka Laboratory of Geosciences and Environment of University of Nangui Abrogoua Abidjan C&#244 te d’Ivoire Department of Water Resources National Office of Drinking Water (ONEP) Abidjan C&#244 te d'Ivoire

The operating capacity of the Abidjan’s groundwater became insufficient. The deficit in drinking water resources in the District of Abidjan remains the major concern of the decision maker. The Aghien lagoon stands as one of the most interesting alternatives. However, studies show the levels of pollutions of this resource without lighting out on the causes and sources of these pollutions. The present study extends over the entire catchment of the Aghien lagoon which reveals the presence of urban areas and agricultural activity areas. This raises real concerns for the Ivorian authorities. This study suggests making cartography of the risk levels of pollution on the Aghien lagoon by the surface runoff on the watershed to enlighten the decision-makers on the possible measures to be taken for the protection of this resource. It emerges from it that the risk of contamination of the lagoon is very likely. Agricultural and domestic best practices inside the pouring pond are compulsory to fight against the pollutions of this resource.

关键词： Pollution Risk Watershed GIS Aghien Lagoon Abidjan

Contribution of a Geographical Information System to the Study of Soil Loss Dynamics in the Lobo Catchment (Côte d’Ivoire)

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Journal of Geoscience and Environment Protection 2018年第9期6卷 183-194页

作者： Jean-Philippe Attoungbré Deguy Alexis Yao N’Go hervé kouakou kouassi Emile Gneneyougo Soro Albert Tié Bi Goula Laboratory of Geosciences and Environment UFR Environmental Science and Management Nangui Abrogoua University Abidjan C&#244 te d’Ivoire Laboratory of Sciences and Technologies of Water UFR Environment University Jean Lorougnon Guédé Daloa C&#244 te d’Ivoire

The Lobo watershed is highly anthropogenic since it has become the main production area for cocoa and coffee in C?te d’Ivoire. It therefore seems important to quantify soil loss by water erosion in this region. The Wischmeier modeling was used to model the main factors involved in erosive phenomena. Crosscutting of thematic maps and the application of the USLE formulas made possible to evaluate the erosion rate at the watershed scale in 1986 and 2014. Although soil is susceptible to erosion and erosivity is increased, the results indicate a growth in soil loss estimated at 90.12%. Some agroforestry efforts are still possible to help reducing those soil losses.

关键词： Water Erosion Soil Loss Universal Soil Loss Equation Geographical Information System Lobo

Impact of the Condition of Drinking Water Supply Networks on the Quality of Water Intended for Consumption: The Case of the Network in the Commune of Daloa (Central West of Côte d’Ivoire)

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Journal of Water Resource and Protection 2023年第12期15卷 677-691页

作者： Amoin Anne Marie kouassi kouakou Lazare kouassi Theophile Gnagne UFR Environnement University Jean Lorougnon Guédé Daloa C&ocircte d’Ivoire UFR des Sciences et Gestion de l’Environnement University Nangui Abrogoua Abidjan C&ocircte d’Ivoire

The potability of drinking water depends not only on the source and the treatment system, but also on the quality of the waterworks. In fact, the quality of drinking water is considerably degraded by the dilapidated state and lack of maintenance of drinking water networks. In Côte d’Ivoire, the majority of drinking water networks in the various towns are ageing. In Daloa, despite the efforts made by the company in charge of water treatment and distribution to make the water drinkable, the water at consumers’ taps is often colored, has an unpleasant aftertaste and settles after collection. As a result, people are concerned about the potability of tap water, and some are turning to alternative sources of drinking water of unknown quality. In order to determine the factors responsible for the deterioration in water color and taste, as well as the sectors of the network most affected, a diagnosis of the network’s equipment was carried out. Water samples taken from the network were analyzed for color and turbidity. The diagnosis revealed that most of the equipment (suction pads, valves, drains and fire hydrants) is outdated and irregularly maintained. Analyses show that the water is more colored in cast-iron and PVC pipes than in asbestos cement pipes. Coloration values in the network range from 0 to 27 UVC for asbestos cement pipes, from 15 to 56 UCV for ductile iron pipes, and from 11 to 102 UCV for PVC pipes. On the over hand, turbidity values vary from 8.02 to 3.32 NTU for ductile cast iron pipes, 8.51 to 16.98 NTU for asbestos cement pipes and 0.9 to 6.98 NTU for PVC pipes. Old cast-iron pipes release ferric ions on contact with water, degrading their color. Old cast-iron pipes release ferric ions into the water, degrading its color. The high color values observed in the vicinity of drains are thought to be due to irregular maintenance of the network. In fact, after network maintenance, a reduction rate ranging from 2% to 73% is observed for turbidity, while for col

关键词： Pipe Water Supply Network Drinking Water Daloa

Prospects for Minimizing the Potential Environmental Impacts of the Hydro-Agricultural Dam of M’Bahiakro(Cote d’Ivoire)

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Journal of Water Resource and Protection 2013年第9期5卷 847-853页

作者： Lazare kouakou kouassi Innocent kouassi Kouame Seraphin kouakou Konan Brou Dibi Soumahoro Moussa Diakaria Kone Dago Gnakri Laboratoire des Sciences de l’eau et de l’Environnement Universite Jean Lorougnon GuedeDaloaCote d’Ivoire Laboratoire Geosciences et Environnement Universite Nangui AbrogouaAbidjanCote d’Ivoire Projet d’Aménagement Hydroagricole de la Vallee du N’Zi ONDR_MINAGRIDimbokroCote d’Ivoire Office National de l’Eau Potable(ONEP) Direction des Ressources en EauAbidjanCote d’Ivoire

This study aims at characterizing the physical environment and suggesting solutions for a better management of the hydro-agricultural dam of M’Bahiakro which is being constructed over the N’Zi River and is the first inflatable dam in Cote d’Ivoire. In this survey, data related to hydrology, characteristics of the dam and the irrigated rice production area were obtained with the Water Resources Agency and the National Office of Rice Development of Cote d’Ivoire. Physicochemical parameters of the N’Zi River were collected seasonally at three monitoring stations. Results showed that the N’Zi River is characterized by a high water level period from April to November and a low water level period from November to April. The gap between the low flows and the high flows is important (about 206 m3/s on average). The annual average flow is 40 m3/s with a standard deviation of 32.52 m3/s and a variation coefficient of 0.88. The SAR average value (1.63) and the average conductivity (78.44 μS/cm) showed that waters of the N’Zi River are of high quality to be used for irrigation. Suspended sediment concentrations do not present significant difference along the river. But the seasonal variations are important;they are higher during the rainy seasons (45.8 mg/L on average) than in the dry seasons (17.7 mg/L on average). The annual solid flux of the N’Zi River is 41897 tons, i.e. 15810 m3 of sediments. The annual sediment flux is important and can lead to high depositions in the line-shaped reservoir of the dam and that calls for attention to control the silting up of the reservoir. Great efforts concerning interdisciplinary approaches, as well as extensive and intensive field work are needed in order to better manage the hydro-agricultural dam of M’Bahiakro.

关键词： Hydrology Irrigation Dam Suspended Sediment N’Zi River

New Asymptotic Results on Fermat-Wiles Theorem

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Advances in Pure Mathematics 2024年第6期14卷 421-441页

作者： Kimou Kouadio Prosper kouakou kouassi Vincent Tanoé François UMRI MSN Felix Houphouet-Boigny National Polytechnic Institute Yamoussoukro Ivory Coast Nangui Abrogoua University Applied Fundamental Sciences Department Abidjan Ivory Coast UFRMI Flix Houphout-Boigny University Abidjan Ivory Coast

We analyse the Diophantine equation of Fermat xp yp = zp with p > 2 a prime, x, y, z positive nonzero integers. We consider the hypothetical solution (a, b, c) of previous equation. We use Fermat main divisors, Diophantine remainders of (a, b, c), an asymptotic approach based on Balzano Weierstrass Analysis Theorem as tools. We construct convergent infinite sequences and establish asymptotic results including the following surprising one. If z y = 1 then there exists a tight bound N such that, for all prime exponents p > N , we have xp yp zp.

关键词： Fermat’s Last Theorem Fermat-Wiles Theorem Kimou’s Divisors Diophantine Quotient Diophantine Remainders Balzano Weierstrass Analysis Theorem

Fermat and Pythagoras Divisors for a New Explicit Proof of Fermat’s Theorem:a⁴ + b⁴ = c⁴. Part I

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Advances in Pure Mathematics 2024年第4期14卷 303-319页

作者： Prosper Kouadio Kimou François Emmanuel Tanoé kouassi Vincent kouakou Laboratoire d’ Informatique et de Math&#233matiques appliqu&#233es Institut Polytechnique F&#233lix Houphou&#235t BOIGNY Yamoussoukro Cote d&#8217Ivoire UFR Mathé matiques et Informatique Universit&#233 F&#233lix Houphouet BOIGNY Abidjan Cote d&#8217Ivoire UFR Sciences Fondamentales Appliqué es Universit&#233 NANGUI ABROGOUA Abidjan Cote d&#8217Ivoire

In this paper we prove in a new way, the well known result, that Fermat’s equation a4 + b4 = c4, is not solvable in ℕ , when abc≠0 . To show this result, it suffices to prove that: ( F 0 ): a 1 4 + ( 2 s b 1 ) 4 = c 1 4 , is not solvable in ℕ , (where a 1 , b 1 , c 1 ∈2ℕ+1 , pairwise primes, with necessarly 2≤s∈ℕ ). The key idea of our proof is to show that if (F0) holds, then there exist α 2 , β 2 , γ 2 ∈2ℕ+1 , such that ( F 1 ): α 2 4 + ( 2 s−1 β 2 ) 4 = γ 2 4 , holds too. From where, one conclude that it is not possible, because if we choose the quantity 2 ≤ s, as minimal in value among all the solutions of ( F 0 ) , then ( α 2 ,2 s−1 β 2 , γ 2 ) is also a solution of Fermat’s type, but with 2≤s−10) is solvable in ( a 1 ,2 s b 1 , c 1 ) , s ≥ 2 like above;afterwards, proceeding with “Pythagorician divisors”, we creat the notions of “Fermat’s b-absolute divisors”: ( d b , d ′ b ) which it uses hereafter. Then to conclude our proof, we establish the following main theorem: there is an equivalence between (i) and (ii): (i) (F0): a 1 4 + ( 2 s b 1 ) 4 = c 1 4 , is solvable in ℕ , with 2≤s∈ℕ , ( a 1 , b 1 , c 1 )∈ ( 2ℕ+1 ) 3 , coprime in pairs. (ii) ∃( a 1 , b 1 , c 1 )∈ ( 2ℕ+1 ) 3 , coprime in pairs, for wich: ∃( b ′ 2 , b 2 , b ″ 2 )∈ ( 2ℕ+1 ) 3 coprime in pairs, and 2≤s∈ℕ , checking b 1 = b ′ 2 b 2 b ″ 2 , and such that for notations: S=s−λ( s−1 ) , with λ∈{ 0,1 } defined by c 1 − a 1 2 ≡λ( mod2 ) , d b =gcd( 2 s b 1 , c 1 − a 1 )= 2 S b 2 and d ′ b = 2 s−S b ′ 2 = 2 s B 2 d b , where ( 2 s B 2 ) 2 =gcd( b 1 2 , c 1 2 − a 1 2 ) , the following system is checked: { c 1 − a 1 = d b 4 2 2+λ = 2 2−λ ( 2 S−1 b 2 ) 4 c 1 + a 1 = 2 1+λ d ′ b 4 = 2 1+λ ( 2 s−S b ′ 2 ) 4 c 1 2 + a 1 2 =2 b ″ 2 4;and this system implies: ( b 1−λ,2 4 ) 2 + ( 2 4s−3 b λ,2 4 ) 2 = ( b ″ 2 2 ) 2;where: ( b 1−λ,2 , b λ,2 , b ″ 2 )={ ( b ′ 2 , b 2 , b ″ 2 ) if λ=

关键词： Factorisation in ℤ Greatest Common Divisor Pythagoras Equation Pythagorician Triplets Fermat's Equations Pythagorician Divisors Fermat's Divisors Diophantine Equations of Degree 2 4-Integral Closure of ℤ in ℚ