TC Zambia: Groundwater Management with Focus on the Upper Kafue Catchment

Report of the project:

Zambia - Groundwater Management in the Upper Kafue Catchment

Location of the project area

Background and Objectives:
The Kafue River is the largest tributary of the Zambezi River and the majority of the Zambian population lives in this basin. The upper part of its catchment has a total area of about 97,000 km² and covers the complete Copperbelt Province as well as parts of the Northwestern and Central Province. The climate can be classified as humid subtropical with precipitation amounts of 1,100 to 1,250 mm per year, mainly occurring during the hot rainy season from November to April. During the subsequent dry season, the initially cooler temperatures progressively increase.

Mining industry, commercial agriculture and domestic users compete for the groundwater resources in the Upper Kafue sub-basin. However, these resources are insufficiently understood and partly affected by poor sanitation and contamination due to mining practices. Yet, technical guidelines and planning tools to manage the groundwater efficiently, like hydrogeological maps, are missing.

As a partner of the Ministry of Water Development, Sanitation and Environmental Protection, the Federal Institute for Geosciences and Natural Resources (BGR) closely cooperates with the Water Resources Management Authority (WARMA), which was founded in 2014, and subordinate authorities like the Kafue Catchment Office, the Upper Kafue Sub-Catchment Office and the Provincial Water Office in Ndola, the latter being part of the Department for Water Resources Development (DWRD). The BGR supports WARMA and its assigned local authorities in the development of technical capacities to ensure a sustainable management of groundwater resources. The main aim of the current project (2016-2019) is to support WARMA in the development of groundwater management plans for catchments and sub-catchments. Guidelines and concepts for the establishment of a groundwater management plan are prepared in order to support the regulation of groundwater use on catchment scale as prescribed by the Water Resources Management Act from 2011.

The overall aim of the cooperation is to strengthen the technical capacities of the authorities, which will be fostered by training WARMA’s staff in the development of groundwater management plans. Moreover, all results of the project are continuously shared and discussed with the Zambian partners and presented to stakeholders.

Monitoring site at the Kafulafuta

Methods:
Groundwater management components forming part of the overall management plan are developed and implemented in three representative pilot catchments. The three catchments of the Kafulafuta, the Kafubu and the Mpongwe rivers, all belonging to the Upper Kafue sub-basin, were selected as pilot areas, since their groundwater resources are limited and the availability of data is inadequate. The Kafulafuta and the Kafubu catchments are home to major mining activities and urban areas, like Ndola, the third biggest city of Zambia. While in these two catchments aquifers of basement rocks (formed by gneiss and granite) and the Lower Roan/Muva series (formed by quartzite) prevail, dolomite karst aquifers dominate the Mpongwe catchment, whose groundwater-fed irrigation agriculture is of national importance.

The exemplary implementation of components of a groundwater management plan in these pilot areas is thought to serve as template for other catchments. The components supported under the project comprise:

Design and implementation of a groundwater monitoring network including hydrochemical reconnaissance surveys
Hydrogeological mapping
Groundwater potential estimates

Measurement of the Kafubu discharge

The centrepiece of such a plan is the estimation of the groundwater water budget, which serves as basis for the allocation of groundwater abstraction permits and the licensing of drilling applications. A detailed understanding of the hydrological and the hydrogeological conditions of the area under consideration is key to developing a suitable management plan. Hence, the initial step was to draft and implement a monitoring concept. Based on a literature review, a guideline to develop a groundwater monitoring network was compiled and applied to the area.

Based on field and monitoring data the most important groundwater bodies and groundwater flow directions are identified and the impacts of groundwater usage on the reserves can be estimated.

Elements of the monitoring are

to determine all water budget components like discharge, precipitation and evapotranspiration to derive groundwater recharge rates,
to identify and analyse the current groundwater usage,
to conduct hydrochemical and isotope analyses to evaluate the groundwater quality and gain insights about the age and the origin of the groundwater, and
to develop recommendations for a long-term monitoring.

Together, the gathered data enable an estimation of the sustainable yield of the aquifers.

Groundwater flow contours

First Results:
Itawa Spring in Ndola: As a first step of the investigation of the Kafubu River catchment, the Itawa Spring in the municipal area of Ndola was studied. The spring is an important water resource for a brewery, and two nearby artesian wells supply local households with water. To enhance the so far limited hydrogeological knowledge of the spring, the available geological information was interpreted in combination with measurements of groundwater levels and hydrochemical analyses (including an investigation of stable isotopes) to develop a conceptual model of the groundwater flow. The findings, which were used to derive preliminary groundwater protection zones, indicate that the spring water is of recent origin with the recharge area in close distance to the spring. Besides the protection zones, recommendations of the study encompass changing the land use practice on the slopes around the spring to reduce the on-going erosion, which causes the spring’s migration towards a railway track, and mitigating contamination threats arising from bad sanitation conditions close to the spring.

Monitoring network installed in the project area

Hydrogeology of Solwezi: The town of Solwezi is representative for several issues that the mining towns in the Upper Kafue Sub-Catchment face. While hydrogeological knowledge is limited, the fast-growing population and the mining present threats to both groundwater quality and quantity. A hydrochemical reconnaissance study did not detect any contamination by heavy metals, while microbiological groundwater pollution by E. coli was a common problem in the shallow, unconfined Solwezi Shist Aquifer that underlies most of the populated area. Protection zones for existing production boreholes were proposed, which are however already encroached. Hence, one of the recommendations given to secure a sustainable future groundwater use was to develop new wellfields in unsettled areas of the marble aquifer that is found in the surroundings of Solwezi. In case one of these wellfields is going to be used, it is crucial to accompany the installation process with a delineation of protection zones to secure the groundwater resources.

Monitoring: A monitoring network for the study area was designed and installed, which is operative since November 2016. The network covers the three pilot study areas and comprises 9 river gauging stations and 14 monitoring boreholes. In addition to the network, 3 hydrochemical sampling campaigns and 2 water table measurement campaigns were conducted.

Hydrogeological Map of Zambia

National Hydrogeological Map of Zambia: Water management in Zambia is catchment-based, which is why basic hydrogeological information is needed for wide areas. Therefore, the project updated and re-issued the National Hydrogeological Map of Zambia, which had been out-of-print. The map provides information on the geology and an assessment of the groundwater potential. It serves as a planning tool for groundwater abstractions and explorations and to manage groundwater resources on catchment level. The map is available for purchase at WARMA.

Groundwater contamination as possible factor in cholera outbreaks in Lusaka: From June 2018 to April 2019 BGR and WARMA were implementing a side project entitled "Groundwater advisory for the long-term prevention of cholera epidemics in Lusaka, Zambia". The study investigated possible links between groundwater contamination, hydrogeological setting and the occurrence of cholera cases in Lusaka in the rainy season 2017/2018, partly rehabilitated the groundwater monitoring network of Lusaka and issued a modified version of the groundwater vulnerability map of Lusaka. For results of the side project, refer to the website: www.bgr.bund.de/zambia-lusaka-vm

Partner: