Mapping groundwater quality degradation beneath growing rural towns in sub-Saharan Africa

地下水往往比地表水更可靠，更不容易受到污染，对气候变化的适应能力更强。撒哈拉以南非洲(SSA)的许多不断扩大的城市地区依靠地下水供水。然而，城市地下水受到厕所、生活垃圾和工业活动污染的影响。从农村到城市土地利用的变化导致地下水补给以及水质和需求的戏剧性变化。尽管政府和非政府组织努力增加获得安全地下水的机会，但这些地区最脆弱的人仍然依赖不断恶化的水质来源不足。安全用水对家庭使用、经济活动和工业以及公共服务都很重要。与大城市(如卢萨卡、拉各斯和达喀尔)相比，SSA不断发展的农村城镇下的地下水资源知之甚少，而且最近的重点是农村环境。鉴于南沙地区有大量规模较小但发展迅速的依赖地下水的农村城镇，制定有效的战略以保护资源免受不可避免的污染是当务之急。这就需要有效地确定这一资源的特征，并开发实用工具，将风险与可在整个南沙群岛使用的地下水资源联系起来。这项建议的重点是提高我们对城市发展对南沙地区地下水质量影响的理解。作为这项工作的一部分，将开发和测试用于不同发展方案的地下水风险测绘工具，使这一方法能够在资源最少的南沙其他城镇使用。作为这项工作的一部分，将利用已出版的灰色文献，对目前对整个南沙地区城市中心地下地下水质量的认识进行全面审查。一项跨学科的试点研究将调查农村城镇内不同开发区域下的地下水质量，并将其与邻近农村地区的天然水质量进行比较。这种比较将被用来测试映射方法。赞比亚是SSA的中低收入国家，据估计，那里约30%的人无法获得安全饮用水。这项初步研究将包括收集新的微生物和水化学数据。将在对比降雨/补给的情况下调查水质，以确定在强降雨期间的污染风险。将试行原位有机物质荧光技术，作为追踪和筛选地下水废水污染的潜在工具。本研究将为指导南沙地区地下水管理乡镇的研究、政策和发展奠定良好的科学基础。这项工作的输出将是新颖的，并在整个SSA中得到应用。这项工作将在一次研讨会上达到高潮，以传播调查结果，并与来自赞比亚和整个南沙群岛的主要利益攸关方进行讨论。

Groundwater is often more reliable and less vulnerable to pollution than surface water, and more resilient to climate variability. Many expanding urban areas in sub-Saharan Africa (SSA) are dependent on groundwater for water-supply. However, urban groundwater is impacted by pollution from latrines, domestic waste and industrial activities. The change from rural to urban landuse causes dramatic changes in groundwater recharge, as well as in water quality and demand. Despite government and NGO efforts to increase access to safe groundwater, the most vulnerable in these areas still rely on inadequate sources of deteriorating quality. Safe water is important for domestic use, economic activities and industry, as well as public services. Groundwater resources beneath growing rural towns in SSA are poorly understood compared to large cities (e.g. Lusaka, Lagos and Dakar) and there has been a recent focus on rural settings. Given the large numbers of smaller but rapidly growing rural, groundwater-dependent towns in SSA, the development of effective strategies to protect the resource from inevitable contamination is a priority. This requires this resource to be effectively characterised and for practical tools to be developed for mapping risk to groundwater resources that can be used across SSA. This proposal focuses on improving our understanding of the impact of urban development on groundwater quality in SSA. As part of this a groundwater risk mapping tool for use in different development scenarios will be develop and tested, enabling this approach to be used in other towns in SSA with minimal resources. As part of this work a comprehensive review of the current understanding, drawing on published and grey literature, of groundwater quality beneath urban centres across SSA will be assessed. An interdisciplinary pilot study will investigate groundwater quality beneath zones of contrasting development within a rural town and compare this with the quality of 'natural' water in adjacent rural settings. The comparison will be used to test the mapping approach. Zambia is a lower-middle income country in SSA, where it is estimated that around 30% of people don't have access to safe drinking water. This pilot study will include the collection of new microbiological and hydrochemical data. Water quality will be investigated in contrasting rainfall/recharge conditions to characterise contamination risk during intense rainfall. In-situ organic matter fluorescence techniques will be piloted as potential tools for tracking and screening for waste water pollution in groundwater. This study will test new methods and help develop a good scientific base for guiding research, policy and development for groundwater management rural towns in SSA. The outputs from this work will be novel, and have applications across SSA. This work will culminate in a workshop to disseminate and discuss findings with key stakeholders from Zambia and across SSA.