Department of Environmental Health Science and Technology, Jimma University, 378, Jimma, Ethiopia.
Department of Biological Sciences and Department of Geography, University of Cincinnati, Cincinnati, OH, 45221, USA.
Environ Monit Assess. 2018 Feb 22;190(3):163. doi: 10.1007/s10661-018-6527-4.
This research investigated the spatiotemporal variation of water quality in the Gilgel Gibe reservoir, Ethiopia, using physicochemical water quality parameters. Nonparametric tests and multivariate statistical techniques were used to evaluate data sets measured during dry and rainy seasons. Electrical conductivity (EC), pH, biochemical oxygen demand (BOD), total phosphorus (TP), total nitrogen (TN), nitrate (NO), total dissolved solids (TDSs), and total suspended solids (TSSs) were all significantly different among seasons (Mann-Whitney U test, p < 0.01). In addition, principal component analysis distinguished dry season samples from wet season samples. The dry season was positively associated with EC, pH, TP, TN, NO, TDS, and TSS and negatively associated with BOD. The wet season was in contrast associated with high values of turbidity, soluble reactive phosphorus (SRP), water temperature, and dissolved oxygen (DO). Within the reservoir, spatial variation was observed for some of the water quality parameters, with significant difference at p = < 0.05. Overall, high nutrient concentrations suggest eutrophic conditions, likely due to high nutrient loading from the watershed. Levels of TSS, attributed to inputs from tributaries, have been excessive enough to inhibit light penetration and thus have a considerable impact on the aquatic food web. Our findings indicate that the reservoir is at high risk of eutrophication and siltation, and hence, urgent action should target the planning and implementation of integrated watershed management for this and similar reservoirs in the region.
本研究采用理化水质参数调查了埃塞俄比亚吉尔格尔吉贝水库的水质时空变化。使用非参数检验和多元统计技术评估了旱季和雨季测量的数据集。电导率 (EC)、pH 值、生化需氧量 (BOD)、总磷 (TP)、总氮 (TN)、硝酸盐 (NO)、总溶解固体 (TDS) 和总悬浮固体 (TSS) 在季节之间均有显著差异 (Mann-Whitney U 检验，p<0.01)。此外，主成分分析将旱季样本与雨季样本区分开来。旱季与 EC、pH 值、TP、TN、NO、TDS 和 TSS 呈正相关，与 BOD 呈负相关。相比之下，雨季与浊度、可溶性反应磷 (SRP)、水温和溶解氧 (DO) 的高值有关。在水库内，一些水质参数存在空间变化，在 p<0.05 时有显著差异。总体而言，高营养浓度表明处于富营养状态，这可能是由于流域的高养分负荷所致。TSS 水平归因于支流的输入，已经过高，足以抑制光的穿透，因此对水生食物网有重大影响。我们的研究结果表明，水库处于富营养化和淤积的高风险之中，因此，应针对该地区和类似水库的综合流域管理进行规划和实施。
