The convenience and quality of life provided by dams is highly dependent on the quality of the retained water. Human intervention plays an important role in defining the quality of the retained water as expanding human populations have a large impact on the surrounding environment and the, quality of impounded water. The types and extent of human activities taking place in and around the dam will generally have an effect on the unique physical and chemical properties of water within the reservoir, thereby affecting the biodiversity and related functions thereof.

Therefore, the need for comprehensive water quality assessment and reporting tools including contamination susceptibility indices cannot be overemphasized. Thus, the study aimed at developing a contamination susceptibility index for the Goreangab dam by evaluating the effects of anthropogenic activities on surface water quality through the analysis of the physico-chemical properties of the water column and sediments, an aquatic invertebrate evaluation and pollution risk assessment, using the Pollution Load and the wastewater presence, recreational impact, agricultural impact, size of the watershed, transportation avenues, industrial impact and vegetative ground cover, (WRASTIC) indices.

Analytical experimental studies were used as references to methods employed in this research. Water, aquatic invertebrates and sediment samples were collected from 6 sampling sites, selected on the basis of their exposure to anthropogenic activity. The quality parameters investigated included dissolved oxygen, pH, total dissolved solids, chemical oxygen demand, temperature, electric conductivity and select heavy metals Pb, As, Fe, Zn, and Hg. Water and sediment samples were analysed using the Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) and X-ray fluorescence (XRF) methods respectively. These were compared to the allowable limits stipulated in the Namibian Water Act (Act No. 54 of 1956). With the exception of TDS, Electric Conductivity and COD all other physical parameters recorded levels below the national set standard.

Metal composition in the water column were all below the allowable limits, decreasing in the order Fe > Zn > Hg > Cd > As > Pb. The sampling stations upstream recorded higher average concentrations of metals in comparison to the downstream areas.

The Pollution Load Index (PLI) results indicated deteriorating quality of soil sediments for all sampling stations, with higher deterioration upstream as these areas were privy to sewage and wastewater effluent. The aquatic invertebrate inventory and identification results categorised upstream Goreangab dam as a seriously modified habitat with very poor water quality whereas the downstream areas were found to be moderately modified. The average heavy metal concentrations were found to be below allowable limits for most of the sampling sites. Based on bio-monitoring and soil analyses results, there was indication of poor and deteriorating water quality at all sampling sites.

The WRASTIC index indicated that the watershed was at high risk of contamination with a score of 51 and also identified five (5) of the sampling stations as risky areas serving as entry points for pollutants into the dam. The WRASTIC score is subject to a 3-year waver, indicating that the dam will be at a higher risk sooner as activity around the watershed continues to increase. The overall study results suggest that anthropogenic activity is a major factor in the contamination of the watershed and contributes greatly to its vulnerability. Regular screening of the Goreangab dam for sources of pollution will need to take place, along with continuous quality monitoring and assessment for the successful protection and restoration of the dam.

大坝所提供的便利和生活质量在很大程度上取决于保留水的质量。人为干预在定义保留水的质量方面起着重要作用，因为不断扩大的人口数量对周围环境和蓄水质量有很大影响。大坝内及其周围发生的人类活动的类型和程度通常会影响水库内水的独特物理和化学性质，从而影响生物多样性及其相关功能。

因此，不能过分强调对综合水质评估和报告工具（包括污染敏感性指数）的需求。因此，该研究旨在通过分析水柱和沉积物的理化特性，水生无脊椎动物评估和污染风险评估，评估人为活动对地表水水质的影响，从而为戈雷安格布水坝建立一个污染敏感性指数。 ，使用污染负荷和废水的存在，娱乐影响，农业影响，分水岭的大小，运输途径，工业影响和植物植被覆盖率（WRASTIC）指标。

分析性实验研究被用作本研究中所用方法的参考。从6个采样点收集水，水生无脊椎动物和沉积物样品，并根据其暴露于人为活动的条件进行选择。研究的质量参数包括溶解氧，pH，总溶解固体，化学需氧量，温度，电导率以及选择的重金属Pb，As，Fe，Zn和Hg。分别使用电感耦合等离子体发射光谱（ICP-OES）和X射线荧光（XRF）方法分析了水和沉积物样品。将这些与《纳米比亚水法》（1956年第54号法案）中规定的允许限值进行了比较。除TDS，电导率和COD以外，其他所有物理参数均记录在低于国家设定标准的水平。

水柱中的金属成分均在允许限度以下，按Fe> Zn> Hg> Cd> As> Pb的顺序降低。与下游地区相比，上游的采样站记录的金属平均浓度更高。

污染负荷指数（PLI）结果表明，所有采样站的土壤沉积物质量均在下降，上游的恶化程度更高，因为这些地区缺乏污水和废水。水生无脊椎动物的清单和鉴定结果将上游Goreangab大坝归类为水质非常差的经过严重改造的生境，而发现下游地区则受到了适度的改造。发现大多数采样点的平均重金属浓度均低于允许的限值。根据生物监测和土壤分析结果，有迹象表明所有采样点的水质都在恶化。

WRASTIC指数表明该流域受到污染的风险很高，得分为51，并且确定了五（5）个采样站为危险区域，是进入大坝的污染物的入口点。WRASTIC评分受到3年的波动影响，表明随着流域周围活动的继续增加，大坝将面临更高的风险。总体研究结果表明，人为活动是流域污染的主要因素，并对其流域的脆弱性做出了很大贡献。需要对Goreangab大坝进行定期的污染源筛选，并进行持续的质量监测和评估，以成功保护和修复大坝。