Pollutant Transformation Performance and Model Development in African Wetland Systems: Large Catchment Extrapolation

  • Herbert John Bavor
  • Michael Thomas Waters

Two wetland systems in the Lake Victoria Basin, western Kenya, were investigated and monitored to assess buffering capacity and also to develop a model approach to evaluating larger-scale pollutant-buffering capacity of regional wetlands. The Dionosoyiet wetland was located in the highlands of the Rift Valley Province, at approximately 2,000 m altitude. It was located immediately adjacent the Kericho town centre, covered a 34 ha area and was set in a catchment of 23 km2. The wetland was located in the upper reaches of the Sondu-Miriu river system which flows into Lake Victoria. The 560 ha Chepkoilel wetland, near Eldoret, had an agricultural catchment area of 210 km2 with major inflows to the wetland contributed by the Sergoit-Misikuri river system. The catchment drained areas of mild slopes ranging up to 2,160 m above sea level. Water-quality investigations were undertaken in the wetlands from June 2004 to April 2005 for nutrients and suspended solids. Hydrology and water-quality modelling were performed utilising the LAVINKSWEB model. The model was adapted to incorporate a rainfall-runoff module based on the isochronal histogram technique and a partially stochastic prediction of water quality (TSS, TN and TP) based on incoming flow rates. Using the data gathered from June 2004 to April 2005 for calibration and earlier climatic data, modelling was performed to cover an 11-year period, from January 1994 to December 2004, and indicated that the wetland removed 43% TSS, 41% TP and 20% TN with average areal removal rates of 21.3 TSS, 0.038 TP and 1.03 TN (kg ha–1 day–1) for the Dionosoyiet system and considerably greater removal from the Chepkoilel system. The findings and model development show that in addition to being critical ecosystem diversity reservoirs and central community/agricultural-activity resources, the wetlands perform significant functions of water-quality improvement. The preservation of these wetlands and other similar wetlands is important in ensuring sustainable utilisation of water resources in the Lake Victoria Basin.


Buffering Kenya Lake Victoria modelling nutrients runoff surface flow 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Bavor, H.J., Davies, C.M., & Sakadevan, K. (2001). Removal of storm water associated nutrients and bacteria in constructed wetland and water pollution control pond systems. In J. Vymazal (Ed.), Transformation of nutrients in natural and constructed wetlands (pp. 483–495). Leiden, Netherlands: Backhuys.Google Scholar
  2. COWI. (2002) Consultants to the Water Quality Component, Annual Report of Lake Victoria Environment Management Programme (LVEMP): Water Quality Component, Kisumu, Kenya.Google Scholar
  3. Lawrence, I., & Breen, P. (1998). Design guidelines: Stormwater pollution control ponds and wetlands. Canberra, Australia: CRC for Freshwater Ecology.Google Scholar
  4. Mwanuzi, F., Aalderink, H., & Mdamo, L. (2003). Simulation of pollution buffering capacity of wetlands fringing Lake Victoria. Environment International, 29, 95–103.CrossRefGoogle Scholar
  5. Ngirigacha, H.W. (2000): The potential of Cyperus immensus, Cyperus papyrus, Typha domingensis and Phragmites mauritianus for pulp and paper mill waste water treatment. MSc Thesis, DEW 130 IHE Delft, The Netherlands.Google Scholar
  6. Ntiba, M.J., Kudoja, W.M., & Mukasa, C.T. (2001). Management issues in the Lake Victoria watershed. Lakes Reservoirs Research and Management, 6(3), 211–216.CrossRefGoogle Scholar
  7. Van der Knaap, M., Ntiba, M.J., & Cowx, I.G. (2002). Key elements of fisheries management of Lake Victoria. Aquatic Ecosystem Health and Management, 593, 245–254.Google Scholar
  8. Verschuren, D., Johnson, T.C., Kling, H.J., Edgington, D.N., Leavitt, P.R., Brown, E.T., Talbot, M.R., & Hecky, R.E. (2002). History and timing of human impact on Lake Victoria, East Africa. Proceedings of the Royal Society of London, Series B, 269, 289–294.CrossRefGoogle Scholar

Copyright information

© Springer Science + Business Media B.V 2008

Authors and Affiliations

  • Herbert John Bavor
    • 1
  • Michael Thomas Waters
    • 2
  1. 1.Centre for Water and Environmental TechnologyUniversity of Western Sydney – HawkesburyAustralia
  2. 2.SMEC InternationalAustralia

Personalised recommendations