sues in the water sector of the Zambezi River Basin is presented in Table 2.10.
Governance Issues
Some governance issues and resultant challenges are shown in Table 2.11. These have an impact on the manage- ment of the water resources of the Zambezi River, which consequently af- fects the wellbeing of the environment.
Groundwater Depletion
Various studies of the weathered and fractured Precambrian Basement Com- plex aquifers of southern Africa were undertaken by the British Geological Survey (BGS) staff primarily in Botswana, Malawi and Zimbabwe dur- ing 1985 to 1993, including the installa- tion of collector well systems. BGS staff also studied the impact of drought on groundwater resources in Malawi, South Africa and Zimbabwe during 1996-97 (BGS 2015).
SADC-related policy studies of the regional water resources followed the publication of the Protocol on Shared Watercourse Systems in SADC in 1998
Table 2.9 IInter Basin Water Transfers In Southern Africa
River Country River/Area Country
Cunene Angola/Namibia Cuvelai Namibia E Primary
Okavango Angola/Namibia Central Namibia Namibia E Primary/Irrigation
Primary/Environmental
Zambezi/Chobe Angola/Zambia/ Selibe- Pikwe/ Botswana P Mining/Industrial
Namibia/ Gaborone
Zimbabwe/ Botswana
Zambezi/Chobe Angola/Zambia/ Central Namibia Namibia P Primary/Irrigation
Namibia/ Primary/Environmental
Zambezi Angola/Zambia/ Caprivi Strip Namibia P Irrigation
Namibia/
Zimbabwe/Botswana
Zambezi Angola/Zambia/ Vaal/Pretoria South Africa P Irrigation
Namibia/
Zimbabwe/Botswana
Zambezi Zambia/Zimbabwe Gwayi/Bulawayo Zimbabwe P Primary/Irrigation
Industrial/Primary
Congo Democratic Okavango Namibia P Primary/Industrial
Republic of Congo
Congo Democratic Zambezi Namibia/Botswana/ P Primary/Industrial/
Republic of Congo South Africa/Zimbabwe Irrigation/Mining
Tumbare, M. J., Management of Shared Watercourses in Southern Africa, 2005; and The Management of the Zambezi River Basin and Kariba Dam, 2010
43
Table 2.10 KKey Challenges and Issues in the Water Sector in the Zambezi River Basin
CHALLENGE/ISSUE SUMMARY
Data Access to reliable data, both in the water resources and water services sectors, inadequate infra- structure and information systems for water resources monitoring, unreliable data on water use and water loss in municipalities and other different sectors, and inadequate data on access to water and sanitation.
Capacity Limited human resource capacity in both the technical and managerial fields to deliver sustainable water services and to manage water resources effectively.
Water Sector Infrastructure The infrastructure challenges can be summarised as follows:
There is limited water resources storage infrastructure at local levels, making countries vulnerable to droughts, floods and to the impacts of climate change;
Water resources and water services infrastructure, including large dams, irrigation canals, pumps, water and waste water treatment works, and reticulation systems are often poorly maintained, re- sulting in safety issues and water wastage;
Large numbers of people with inadequate access to water and sanitation infrastructure and related services impacts negatively on health and livelihoods;
High levels of illegal connections result in water theft, reduced revenue and high rates of water loss. Financing Inadequate financial resources is a challenge to infrastructure development and expansion, and for operations and maintenance. Poor revenue collection for water services remains a major challenge that impacts on the ability to deliver sustainable services.
Climate Change Considerable work is required to understand the likely impacts of climate change, at the catchment level in particular. This requires further research and investment, including improved flood and drought management, extended hydrological gauging networks, improved hydrological modelling, improved groundwater modelling, improved data processing, appropriate drought and flood man- agement systems, enhanced disaster/risk management and improved communication and transfer of information.
Managing Water Quality There are two critical aspects to managing water quality that need to be addressed: o protecting the water quality in surface and groundwater resources, and o ensuring the quality and safety of drinking water.
The former links to issues of pollution control and treatment, including pollution from municipal, agricultural, industrial and mining waste. The latter requires effective treatment of water to potable standards, in urban and rural areas.
Sanitation Sanitation delivery has lagged behind the delivery of water services in the Zambezi River Basin ri- parian states. There are a number of challenges around ensuring appropriate sanitation, including issues of sustainable, waterless or low water use sanitation that are appropriate to the local context. A further challenge that should be addressed by the Basin states is how to manage productive and safe wastewater, excreta and faecal sludge for nutrient re-use in agriculture and aquaculture and how this can enhance resilience to climate change. This includes understanding the science, the business models, the social change required, as well as establishment of safety standards for reusing wastewater in agriculture.
Adapted from SADC 2011b, Climate Change Adaptation in SADC: A Strategy for the Water Sector, 2011
and the Southern Africa Water Vision for Action in 2000. Various strategic ac- tion plans followed during 2000-2005. Those related to the production of a hydro-geological map with reviews of country specific data (2002) and the re- gional situation analysis of drought and its impact upon groundwater supply management (2005) were the most sig- nificant drivers of hydro-geological
studies. Emphasis has also been placed upon integrated water resources man- agement especially within transbound- ary settings (BGS 2015).
About 70 percent of the population of the Zambezi River Basin lives in the rural areas where groundwater is of crit- ical importance to the livelihoods of this rural population. This is because groundwater is a more suitable and ap-
44
propriate water supply source for low population areas requiring minimal reticulation. The rural communities rely on groundwater for their domestic water supply, stock watering, and horti- culture.
Groundwater is important particu- larly in arid and semi-arid regions of the Zambezi River Basin and augments sur- face water supplies particularly in drought seasons. However, across the
Zambezi as a watercourse, very little groundwater information is readily available for planning purposes and for understanding how surface and ground- water interface for sustainable utilization and conjunctive use. Consequently, there is insufficient capacity and knowl- edge to implement effective manage- ment of groundwater to result in the sustainable use of this water resource of the Zambezi River Basin.
Table 2.11 SSummary of Governance Issues and Impacts in the Zambezi River Basin
IMPACTS
Different water quality standards Different assignment of the value of water Slow realization of regional integration goals
Fragmented water infrastructure development
Low optimization of conjunctive operation of water infrastructure Poor resource mobilization, allocation and utilization
Low level data/information sharing, inadequate synchronization of water infrastructure operation and management
Duplication of effort and resource wastage
Difficulty in accounting for responsibilities in cases of problems Water sector users confused as to who to be answerable to Delays in disaster management/mitigation response
Lack of common understanding of baseline status and priority issues in basin level water management
Weak national water management institutional capacity to perform river basin management tasks
Limited water resources knowledge base for basin-wide development and management
Inadequate effective stakeholder participation in water resources planning, development and management
Communication limitations in some Zambezi River Basin institutions Inadequate utilization of resource opportunities towards implementation of cooperative basin initiatives
Low confidence in the Basin’s Precipitation and Flow Forecasting System Prolonged decision-making and debate on priority and urgent water manage- ment issues – prioritizing sovereignty over transboundary cooperation High vulnerability to extreme weather impacts
Low water use efficiencies and poor maintenance of existing infrastructure Lack of knowledge on project impacts and outputs
Lost opportunities to learn from project lessons. Increased project costs
Resources diverted from intended purposes Sustained or increased poverty levels ISSUES
Policies and Laws in the water sector of riparian states are not harmonised with each other and/or with the SADC Regional water sector protocols
and policies Ineffective basin-wide management of the water resources of the Basin
Institutional capacity constraints
Lack of trust and confidence
Lack of investments in water infrastructure
Poor project monitoring and evaluation systems
Corruption
45
UN, Water a Shared Responsibility - United Nations World Water Development Report 2, 2006
Map 2.6 Groundwater Resources in Southern Africa
Box 2.4 ARTIFICIAL GROUNDWATER RECHARGE
Artificial recharge is the process whereby surface water is transferred underground to be stored in an aquifer. Underground water storage is an efficient way to store water because it is not vulnerable to evaporation losses and it is relatively safe from contamination.
Windhoek, the capital city of Namibia, has a water requirement of about 21 million cubic metres per year. Most of this water comes from 3 dams but some is
sourced from an aquifer and from fully treated recycled water. The Windhoek water banking scheme involves banking surface water in the aquifer as security against droughts. This allows for the dams to be used at greater risk levels, as security lies in sub-surface storage where evaporation and aquifer losses are negligible. The overall aim of the scheme is for the aquifer to be able to supply virtually the en- tire city’s current water use when it is full, and then for it to be rapidly and fully recharged afterwards.
Some of the main reasons for implementing artificial groundwater recharge are:
• Artificial recharge is usually cheaper than conventional
surface water schemes.
• The aquifer offers storage opportunity where surface
storage is not possible.
• The augumentation of existing groundwater supplies is necessary.
Groundwater Strategy 2011
One of Windhoek’s injection boreholes
Map 2.6 shows groundwater re- sources in southern Africa. It is difficult to map groundwater resources due to the inter-linkages of groundwater aquifers as well as inadequate data and information on groundwater to accurately depict a Zambezi River Basin perspective.
The above scenario, coupled with the predictions of extreme weather pat- terns caused by climate change, calls for efforts to store available water resources. This can be realised through construc- tion of dams, groundwater recharge (Box 2.4) and water harvesting.
Wetland Degradation
The Zambezi River and its tributaries have large wetlands, the largest being the Barotse Floodplains in western Zambia and the Kafue Flats in central Zambia. Wetlands provide a wide variety of re- sources for wildlife, flora and fauna as well as a number of products and serv- ices that benefit community livelihoods.
Wetlands also provide hydrologic advan- tages to flood control by reducing the water flow velocity caused by flooding and in the process, storing some flood- waters within the wetland, thus reducing the flood peak.
Almost 20 million people, which is more than 50 percent of the population in the Zambezi River Basin, are concen- trated around wetlands and most com- munities continue to be dependent on hand-dug wells for the supply of potable water. Women and children usu- ally cultivate in wetland ecosystems since these provide enough moisture and fertile soils for agriculture. How- ever, like all large artificial and natural lakes, the wetland surface area results in high evaporation losses.
Major causes of wetland degrada- tion in the Zambezi River Basin include:
• unsustainable wetland resource utilization such as over-fishing and water abstraction;
• siltation of wetlands resulting in loss of mangroves and alteration of the ecosystem habitats; • pollution of wetlands from min-
ing, sewerage and other industrial effluents;
• conversion of wetlands to other land uses such as construction of houses; and
• undervaluation of wetland goods and services.
In Zambia, charcoal production and slash-and-burn agriculture have led to the deterioration of the Lukanga swamp ecosystem, resulting in soil erosion, the turbidity of the water and siltation (ZEMA and others 2012). As a way of conserving wetlands, local farmers from the Simlemba Wetlands in Malawi, of which the majority are women, have de- veloped sustainable strategies that allow the community to use the surrounding
dambos and vleis without destroying the productive ecosystems, as manifested in many different wetland ecosystems throughout the basin (SARDC 2013). Map 2.7 shows the wetlands of the Zambezi River Basin.
Aquatic Invasive Species
Aquatic plants, mostly free-floating species such as Water Hyacinth (Eich-
horniacrassipes), Water Lettuce (Pistias-
tratiotes), Red Water Fern
(Azollafiliculoides), and Kariba Weed (Salviniamolesta) are dominant in the Zambezi River Basin (Turpie and Zyl 2002). Of all the aquatic invasive weeds found in the Zambezi River Basin, water hyacinth growth poses the most challenges throughout the Basin and is most prolific on Lake Chivero, the Kafue Flats, Lake Kariba, and the Lower Shire.
47
SADC/SARDC and others, Zambezi River Basin Atlas of the Changing Environment, 2012
48
Box 2.5 IINVASIVE WEEDS ON LAKE KARIBA
The two main species of invasive aquatic plants on Lake Kariba are the water hyacinth (Eichornia
Crassipes)and the Kariba weed (Salvinia Molesta). The proliferation of these invasive plants on Lake Kariba poses operational problems for hydropower production if the weeds get into the hy- dropower or domestic water supply intake. Lake navigation and fisheries are also negatively af- fected.
The Kariba weed was prevalent on Lake Kariba during the period it was filling in the early 1960s. A grasshopper from South America, Paulina, was introduced in 1969 as part of a biological weed control strategy and also a sardine species commonly known as Kapenta (Liomnothrissa miodon) from Lake Tanganyika. The grasshopper helped to reduce the Kariba weed growth while the Kapenta helped to reduce the lake’s nutrients. As the lake’s ecological balance was gradually achieved, the weed died out and is now rarely observed on the lake.
The water hyacinth on the other hand, became a real nuisance in 1994 when the lake remained at levels lower than normal due to the prolonged below-normal water inflows. The Zambezi River Authority (ZRA) implemented a programme for reducing and controlling the proliferation of the water hyacinth through an extensive aerial spraying in August 1998, using the phenoxy herbicide 2,4-D at the rate of 6 litres/ha. Water and fish samples were taken before, during and after the spraying exercise to determine any detrimental effects. None were detected and this spraying ex- ercise is well-documented (ZRA1999). The spraying of the water hyacinth with 2,4-D was very effective and caused the death and submergence of the treated water hyacinth within one week. A total of 1,671ha were cleared of the water hyacinth.
This was followed by a biological control programme using weevils (Neochetina spp.) on the remaining areas invested by water hyacinth which could not be sprayed, such as at domestic water intake works. This strategy worked well and the water hyacinth growth and proliferation is well under control. ZRA has produced a “Management Tool Box” for the control of invasive weeds on Lake Kariba.
Tumbare 2008a
The weight of the water hyacinth is mainly water and the plant can double its mass every four days or so given warm eutrophic conditions. Thus, the plant actively pumps water through its tissues and releases it into the air in the process of evapotranspiration. Through this process the water loss from the surface of water bodies with invasive species is more than triple that from the same water bodies without these plants. Box 2.5 discusses the growth and control of aquatic invasive weeds on Lake Kariba.