Zambia’s Ministry of Lands, Natural Resources and Environmental Protection is in the process of defining the policy framework and agenda to guide wetlands management. As part of this planning process, The Nature Conservancy (TNC) is partnering with the Ministry and other stakeholders to develop a management plan for the Lukanga Swamps, which is an important biodiversity area and serves as a major hydrological component of the Kafue basin.
FutureWater is contracted to assess the value and contribution of the Lukanga Swamps to the Kafue Basin, which has not yet been evaluated. While the biodiversity value of wetlands in general is widely accepted, evaluating the contribution of hydrological ecosystem services within basin systems is becoming a more commonplace holistic approach. There is need for solid scientific evidence regarding the role the Lukanga Swamps play in water quantity and quality within the Kafue River, and the value this contributes to water security for Lusaka and other surrounding and downstream areas that rely on the inundation and recession of the Lukanga Swamps’ flood waters.
During high flow, Kafue River backs up into the Lukanga Swamps and even overflows into the area during the highest flows, returning to its normal course as the high flows dissipate. The amount contributed and the importance of the Lukanga Swamps and Lukanga river overall to Kafue River flows as a whole is not well understood, making management planning for the area a challenge. Water quality of the Kafue river improves downstream between Kitwe and Ndola bridge gauge and Lubungu stream gauges. As with flows, the role of the Lukanga Swamps has in influencing Kafue river water quality requires determination.
It is assumed that the Lukanga Swamps plays a role in attenuating mining pollution in the Kafue river. If this is the case, then there is a basis to engage mining houses in payment for ecosystem services schemes to help support management of the Lukanga Swamps and its watershed. This would ensure the Lukanga Swamps continue to provide vital ecosystem services, such as water purification. Water quantity (flows) in the Kafue river is also affected by the Lukanga swamps. The extent to which this happens, and will happen is a function of the utilization and health of the Lukanga swamps.
With the Ministry of Lands, Natural Resources and Environmental Protection in the process of developing the overarching policy framework for wetlands, and Water Resources Management Authority (WARMA) defining the Kafue Catchment Plans, TNC planned interventions in the Lukanga will serve as a vital opportunity to inform both processes.
FutureWater will apply a combined approach of (I) remote sensing, (ii) SWAT hydrological modelling, and (iii) WEAP modelling of uses and fluxes of water and contaminants. Based on these tools, the main water fluxes, erosion, sediment loads, and flooding characteristics (extent, duration and number of floods) will be assessed of the swamps. The following resulting key indicators will be derived (combining RS-based and model-based estimates):
- Water levels
- Flooded extent, duration and frequency
- Inundation storage volumes
- Reliance of the swamps on surface waters versus groundwater
- Overall health of the system
- Residence times (related to regulation of flows, and settling of sediments)
- Infiltration periods (related to filtering of contaminants)
Ultimately, the hydrology and ecosystem services valuation of the Lukanga Swamps will be assessed under current management and different future scenarios.