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张晓娟 《水文地质工程地质技术方法动态》2004,(4):37-40
地下水系统的水化学评估可以通过简单和多变量技术来实现，如群组分析、要素分析和其它的一些诸如对比分析等。本文研究的主要目的就是调查苏丹东部的青尼罗河盆地的地下水质量，并验证含水层系统的水化学评估。研究区有两个含水层：努比亚砂质岩层和Al-atshan岩层。努比亚含水层的主要补给是青尼罗河和Dinder河的侧向流渗透补给降水直接入渗补给，Al-atshan含水层补给是靠拉海德河的渗漏和降水入渗。主要的水化学作用为简单的溶解、混合、离子交换和部分离子交换。在努比亚含水层中已经证实了存在有限的反离子交换。三种要素控制了青尼罗河盆地所有的矿化作用和水质。第一种要素包含固体溶解总量、电导体、钠、钾、氯化物、重碳酸盐、硫酸盐和镁。第二种要素包含钙和pH值。第三种要素与地下水中的氟化物浓度有关。本文研究重点强调利用简单的多变量技术作为有效工具评估地下水质量。 相似文献
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Sediment balances in the Blue Nile River Basin 总被引：2，自引：1，他引：1
Yasir SAALI Alessandra CROSATO Yasir AMOHAMED Seifeldin HABDALLA Nigel GWRIGHT 《国际泥沙研究》2014,29(3):316-328
Rapid population growth in the upper Blue Nile basin has led to fast land-use changes from natural forest to agricultural land.This resulted in speeding up the soil erosion process in the highlands and increasing sedimentation further downstream in reservoirs and irrigation canals.At present,several dams are planned across the Blue Nile River in Ethiopia and the Grand Ethiopian Renaissance Dam is currently under construction near the border with Sudan.This will be the largest hydroelectric power plant in Africa.The objective of this paper is to quantify the river flows and sediment loads along the Blue Nile River network.The Soil and Water Assessment Tool was used to estimate the water flows from un-gauged sub-basins.To assess model performance,the estimated sediment loads were compared to the measured ones at selected locations.For the gauged sub-basins,water flows and sediment loads were derived from the available flow and sediment data.To fill in knowledge gaps,this study included a field survey in which new data on suspended solids and flow discharge were collected along the Blue Nile and on a number of tributaries.The comparison between the results of this study and previous estimates of the sediment load of the Blue Nile River at El Deim,near the Ethiopian Sudanese border,show that the sediment budgets have the right order of magnitude,although some uncertainties remain.This gives confidence in the results of this study providing the first sediment balance of the entire Blue Nile catchment at the sub-basin scale. 相似文献
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正高考命题指导思想由"知识立意"向"能力立意"转变,高考命题最基本和最本质的工作目标是"考查能力"。地理学科的核心能力是读图能力、分析问题的能力、应用和实践能力、论证和探究问题的能力。这就要求学生具备完整的知识结构,严谨缜密的思维能力,能够灵活的调动和运用地理知识,需要教师在日常教学和复习备考中重视对学生能力的培养,有针对性的进行指导和训练。 相似文献