Quantitative Assessment of Vulnerability to Flood Hazards in Downstream Area of Mono Basin, South-Eastern Togo: Yoto District

The population located along Mono River in the Yoto district faces great challenges in terms of repeated flood disasters in recent years. This paper aims at assessing the conditions which influence flood damage in the study area by using indicators to compute a Flood Vulnerability Index (FVI). The study relies on Turner?et al.’s vulnerability framework and distinguishes three main components (exposure, susceptibility and resilience) that allow a more in-depth analysis and interpretation of local indicators. As a result flood disaster in the study area is not only due to the extreme variability in terms of flood magnitude and frequency in the Mono River, but also to the interaction between human and the environment. The lack of vegetation along the river bank, the closeness of households’ farmlands to the river body, the type of construction and the position of settlements, the household size, the low level education of household head, the lack of diversification of livelihood strategies, the lack of adequate flood warning system, the lack of willingness and ability to take responsive actions coupled with inadequate emergency services, are identified as main determinants increasing communities’ vulnerability to flood disaster. Furthermore, the computation of Flood Vulnerability Index (FVI) offers easy comparison of communities’ vulnerability to flood disaster and pinpoints the most vulnerable communities. At the end of the study, flood exposure, susceptibility, resilience and vulnerability maps were generated.

Quantification of Carried Sediment Charges through the Outflow in the Basin of Mono River in Benin

The filling of rivers generated by carried solid deposit is a factor for the raising of height of rivers and thus activates the floods and inundations. The quantification of carried solid flow charges through their characterization and the analysis of hydrosedimentary dynamics is the second step of the investigation of the solid flow transport in the Mono river. This study aims to quantify the volume of trapped sediments in function of the variation of the geometry of the shape of sections of the river depending of the slope and the flow rate therefore to evaluate the capacity of transport of eroded solid flows of a watercourse from upstream to downstream. Consequently, the decreasing percentage of deposited alluvium from upstream to downstream is calculated along Mono river. Thus the drawn granulometric curve of sediments and the determinate granulometric characteristics of sediments permit to quantify the carried sediment charges at each chosen section with Engelund-Hansen model in Mono river.

Role of Natural and Anthropogenic Influence on the Salinization of Groundwater from Basement Aquifers in the Middle Part of Mono River Basin, Togo

This study aimed to identify the role of natural and anthropogenic influence on geochemical processes controlling groundwater salinization in the middle portion of the Mono River basin, Togo. Multivariate statistical analysis, geochemical masse balance modeling, and conventional graphical methods were applied to the chemical dataset obtained from 110 groundwater samples collected during two campaigns (March-May 2011 and April 2014). The results showed that groundwater is predominantly fresh, acidic to circumneutral and mixed cations-HCO-3 water types. The proportion of ions (Na+, K+, Cl- and SO2-4) occurring ubiquitously in a saline environment increases substantially with TDS. Two factors, defined as natural and anthropogenic, account for 76.5% of the hydrochemical dataset variance. Based on the hierarchical cluster analysis, groundwater samples are classified into four clusters that corroborate the factor analysis results and illustrate different hydrochemical evolution stages along a topographically-driven groundwater flow path. The primary natural process contributing to cations and bicarbonate ions is the weathering of silicate minerals and possibly secondary carbonates by infiltrating water enriched with soil CO2 gas. Groundwater salinization indicators including Cl-, SO2-4 and NO-3, originate from potential sources such as human and animal wastes, agrochemicals, and deforestation. Thermodynamic equilibrium conditions ranged from saturation to oversaturation with respect to quartz, chalcedony, amorphous silica, calcite, dolomite, sepiolite, and talc. In conjunction with the lowering of CO2 partial pressure and evaporation, these conditions restrict acidic hydrolysis of primary silicates but magnify the groundwater salinization process in the lower elevation areas where soil crusts’ formation is favorable. This study showed the effective use of multivariate statistical analysis and complementary techniques in identifying the significant factors and processes controlling groundwater chemistry.

Variability of Future Rainfall over the Mono River Basin of West-Africa

This study assessed the rainfall trends and changes over Mono river basin under the highest greenhouse gas emission scenario RCP8.5. Simulations of eight regional climate models (RCMs) provided by Africa-CORDEX program were considered. To analyze the performance of a set of regional climate models, the MBE (mean bias error), the RMSE (root mean square error), the volume bias (VB), correlation coefficient (R2) and the t-Test statistics were calculated. The precipitation concentration index (PCI), Mann-Kendall trend test, Theil-Sen’s slope estimator (β), and relative percentage change methods were also adopted for data analysis. Changes from the baseline period 1981-2010 were computed for far future (2061-2090 and 2071-2100). As results, the analysis herein highlighted the multi-models’ mean ability to simulate the Mono river basin rainfall adequately. Two distinct patterns emerged from the calculated PCI indicating that stations in southern basin will have moderate, irregular, and strongly irregular rainfall concentrations, whereas stations in northern basin will have irregular and strongly irregular rainfall concentrations. Significant declining in the rainfall was detected in most stations for the future period. The evolution of the monthly average rainfall amounts will be broadly characterized by a decrease and increase between 32.4 and 12% with late rainy seasons. It is understood that future changes in rainfall distribution and trends will affect the availability of water for crops, which should affect the productivity of rain fed agriculture.

Future Extremes Temperature: Trends and Changes Assessment over the Mono River Basin, Togo (West Africa)

This study assessed the extreme temperatures trends and changes over Mono River Basin under the highest greenhouse gas emission scenario RCP8.5. Simulations of five (5) regional climate models (RCMs) provided by Africa-CORDEX program were selected from the eighth (8) considered. Future trends in temperature percentiles, including extremes, are used to assess changes in the distribution of daily temperature over Mono Basin in Togo. Changes of temperature and Extreme low (high) temperatures from the baseline period 1961-2010 were computed for future (2051-2100). This analysis reveals that in the north of the basin, for the positive trends, the maximum is 0.82°C·year-1 given by model MPI-ESM2 at Tchamba while the strongest negative change is 0.26°C·year-1 given by model MIROC at Sotouboua. In the south of the basin, the strongest negative trend is of 0.03°C·year-1 given by model (A) CNRM-CMA5. The maximum ones of the trends for models-mean are all positive except at Anié. Higher percentiles of minimum and maximum temperature will increase at a greater rate than the lower percentiles during dry and rainy seasons (with differences more pronounced for maximum values) over the north. Concerning future changes, almost all the RCMs predicted an increase of maximum and minimum temperatures over most parts of the Mono Basin, particularly in the north. Finally, results predicted an increase of TX90P (TX10P) and TN90P (TN10P) from 10% to 45% (13% to 40%) and 0% to 35% (12% Mean value), respectively over Mono Basin.

利用环境一号卫星热红外通道反演太湖流域地表温度的3种方法比较

利用太湖流域2010年3月26日过境的1景环境一号卫星热红外数据(轨道号为451/77),根据同步modis数据反演大气水汽含量参数,分别利用覃志豪单窗算法、普适性单通道算法、基于影像的Artis反演算法反演太湖流域地表温度,通过与同期的MOD11_L2级modis温度产品进行对比分析,探寻适合于环境卫星热红外通道反演地表温度的方法,以达到对环境一号卫星热红外数据定量化应用示范的目的。结果表明,相比其他算法,普适性单通道算法精度较高,与modis温度产品温差较小,为+1.23 K,而环境一号卫星过境时间与modis温度产品时差为39 min,因此该方法的反演精度可以接受。

洋河酒厂的多粮工艺创新

洋河酒厂根据白酒市场及消费者口味的变化需求,在酿酒生产工艺上大胆试验、创新,从单粮型改变为多粮型生产工艺,用几年时间逐步摸索出一套具有该公司特点的工艺参数,成功解决了困扰江淮流域浓香型白酒厂多年的"增己降乳"、压窖后第二排"掉排"等问题,使得该公司基础酒质量及洋河酒饮后舒适度明显提高,为该公司打造以"洋河蓝色经典"系列酒为代表的绵柔型白酒,奠定了坚实的基础。

基于Landsat 8 TIRS数据与TVDI的流域地表土壤干旱分析

以漓江上游流域为研究区域,利用较高空间分辨率的Landsat 8 TIRS数据定量反演流域的地表温度,并结合温度-植被干旱指数探讨干旱季节流域地表土壤干旱时空分布特征。结果表明:不同干旱季节,漓江上游流域地表温度分布规律类似,即以林地为主的上游流域地表温度低于以城乡工矿居民用地为主的中下游区域;流域地表土壤以干旱等级为主,部分区域出现极干旱现象,在一定程度上会影响区域农业和旅游业的可持续发展。流域地表土壤干旱程度受土地利用类型影响明显,以林地为主的上游区域地表土壤主要为湿润等级,而以城乡工矿居民用地为主的中下游区域主要为干旱等级。