River Continuum Water Quality Dynamics in the Dry Rangeland Landscape of Lake Elementaita Watershed, Nakuru County, Kenya

Francis Mwaura

doi:10.37284/eajenr.9.1.4320

Francis Mwaura University of Nairobi

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Résumé

The aim of the study was to compare the spatial variability of water quality in rivers within the Lake Elementaita watershed in the Great Rift Valley (GRV) and determine the: a) variation across the three rivers, b) magnitude of change along the river continuums and c) influence of river continuum length (distance), altitudinal gradient and catchment area. Water sampling and testing of sixteen parameters was undertaken in 55 sites in River Mbaruk (19 sites), River Chamuka (16 sites), Mbaruk-Chamuka confluence section (2 sites), River Kariandusi (10 sites) and Lake Elementaita (8 sites). This was undertaken through in-situ testing with a portable multi-parameter analyser (Hanna Model HI-98194) and laboratory analysis using a wide range of techniques, including titrimetric analysis, flame photometry and spectrophotometry. Thereafter, the values of pH, TDS, turbidity, alkalinity, chloride, sulphate, calcium, and magnesium were used for computing the water quality index (WQI) along the three rivers. The findings showed significant water quality variation across the three catchments in relation to water pH, TDS, EC, alkalinity, Cl. and SO4, with a 60-100 fold increase in pH, TDS, EC, Cl. and SO4 from the headwaters to the downstream. The results of the Pearson’s correlation analysis indicated significant positive relationships for:- a) riverine continuum length with TDS, Cl, F- and Na, b) catchment area with pH, TDS, EC, alkalinity, Cl, F, PO4, SO4, Mg, Na and K, and c) inverse relationship for continuum altitudinal gradient with pH, EC, Cl, F- and PO4.

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Références

Addo-Bediako, A. (2021). Spatio-temporal distribution patterns of benthic macroinvertebrate functional feeding groups in the Blyde River, South Africa. Applied Ecology and Environmental Research, 19(3), 2241–2257.

Attila I., Engloner, K.N., Péter D. and Mihály O. (2023). Exploring the trend effects of diffuse anthropogenic pollution in a large river passing through a densely populated area. Heliyon, 9(9), e20120.

Adjovu G.E., Stephen, H. and Ahmad, S. (2023). Spatiotemporal Variability in Total Dissolved Solids and Total Suspended Solids along the Colorado River. Hydrology, 10(125), 125.

Airton, M.C., Morcillo, P., Ijomone, O.M., Venkataramani, V., Harrison, F.E., Lee, E., Bowman, A.B., and Aschner, M. (2019). New Insights on the Role of Manganese in Alzheimer’s Disease and Parkinson’s Disease. International Journal of Environmental Research and Public Health, 16(19).

Azaria S.L., Skutai J. and Boros, E. (2023). Review of chemical properties of inland soda and saline waters in East Africa (Rift Valley region). Journal of Hydrology: Regional Studies, 46, 101323.

Biehler, A., Chaillou, G., Buffin-Bélanger, T. and Baudron, P. (2020). Hydrological connectivity in the aquifer-river continuum: Impact of river stages on the geochemistry of groundwater floodplains. Journal of Hydrology, 590.

Bucher, K., Zhou, W., and Stober, I. (2017). Rocks control the chemical composition of surface water from the high Alpine Zermatt area (Swiss Alps). Swiss Journal of Geosciences, 110(3), 811–831.

Caldwell, P.V., Martin, K.L., Vose, J.M., Baker, J.S., Warziniack, T.W., Costanza, J.K., Frey, G.E., Nehra, A., and Mihiar, C.M. (2023). Forested watersheds provide the highest water quality among all land cover types, but the benefit of this ecosystem service depends on landscape context. Science of the Total Environment, 882.

Chakona, A., Phiri, C., Magadza, C.H.D., and Brendonck, L. (2008). The influence of habitat structure and flow permanence on macroinvertebrate assemblages in temporary rivers in northwestern Zimbabwe. Hydrobiologia, 607(1): 199– 209.

Chidiac, S., El Najjar, P., Ouaini, N., El Rayess, Y., and El Azzi, D. (2023). A comprehensive review of water quality indices (WQIs): history, models, attempts and perspectives. Reviews in Environmental Science and Bio/Technology, 22(2), 349–395.

Cooke, O. (1973). Atomic Absorption Spectrophotometry, 3rd edition. Pye Unicam Ltd., Cambridge.

Cooper, M., Chakraborty, A., and Chakraborty, SS. (2018). Rivers and society: Landscapes, governance and livelihoods. Routledge, Taylor & Francis Group.

Fryirs, K.A., and Brierley, G. J. (2013). Geomorphic analysis of river systems: an approach to reading the landscape. Wiley.

Gibbs, R.J. (1970). Mechanisms controlling world water chemistry. Science. 4:170(3962):1088-1090.

Golterman, H.L., Clymo, R.S. and Ohnstand, M.A. (1978). Methods for Physical and Chemical Analysis of Freshwaters. Second edition. Blackwell, London.

Hong, M.N., Chaney, S., Malyshev, E., Zorzetto, A., Preucil, A., and Shevliakova, E. (2025). LM4-SHARC v1.0: resolving the catchment-scale soil-hillslope aquifer-river continuum for the GFDL Earth system modeling framework. Geoscientific Model Development, 18, 2275–230.

Horowitz, A.J. (2013). A review of selected inorganic surface water quality-monitoring practices: are we really measuring what we think, and if so, are we doing it right? Environmental Science & Technology, 47(6), 2471–2486.

Irani, T., Mostafazadeh, R., and Mousavi, M.S. (2025). Changes in water quality condition at sequential monitoring stations based on IRWQI along the Little Zab River in Northwestern Iran. Scientific Reports, 15(1), 29583.

Jones, N.E., and Schmidt, B.J. (2016). Tributary effects in rivers: interactions of spatial scale, network structure, and landscape characteristics. Canadian Journal of Fisheries and Aquatic Sciences, 74(4), 503–510.

Larsen, S., Bruno, M.C., Vaughan, I.P., and Zolezzi, G. (2019). Testing the River Continuum Concept with geostatistical stream-network models. Ecological Complexity, 39.

Lin, G., Li, X., Cheng, X., Zhao, N., and Zheng, W. (2020). Manganese Exposure Aggravates β-Amyloid Pathology by Microglial Activation. Frontiers in Aging Neuroscience, 12, 556008.

Locke, K.A. (20240. Impacts of land use/land cover on water quality: A contemporary review for researchers and policymakers. Water Quality Research Journal, 59(2), 89–106.

Loendorf, C.R. (2012). The Hohokam-Akimel O’odham Continuum: sociocultural dynamics and projectile point design in the Phoenix Basin, Arizona. Gila River Indian Community Cultural Resource Management Program.

Lukhabi, D.K., and Mensah, P.K., Asare, N.K., Pulumuka-Kamanga, T., and Ouma, K.O. (2023). Adapted Water Quality Indices: Limitations and Potential for Water Quality Monitoring in Africa. Water, 15(9), 1736.

Mackereth, E.J.H. (1963). Some methods of water analysis for limnologists. Sci. Pub. Freshwater Biol. Assoc. (England). Pub. No. 21.

McCall, G.J.H. (1967). Geology of the Nakuru-Thomson’s Falls-Lake Hannington area. Geological Survey of Kenya.

Mwaura, F., and Moore, T.R. (1991). Forest and woodland depletion in the Lake Elementaita Basin, Kenya. Geoforum; 22(1)17–26.

Mwaura, F. (1999). A Spatio-chemical Survey of Hydrogeothermal Springs in Lake Elementaita, Kenya. International Journal of Salt Lake Research 8(2):127-138.

Mwaura, F. and Ogendo, R.B. (1993). Some Aspects of Vegetation Structure in a High Altitude Tropical Lake Elementaita Drainage Basin, Kenya. Eastern & Southern Africa Geographical Journal 4(1)73-89.

Nashima, F.P., Strydom, N.A., and Lamberth, S. (2021). Assessing the rigidity of the river continuum concept to fish species in a fluvially dominated southern African coastal system. Research Square. https://doi.org/10.21203/rs.3.rs-778961/v1.

Oduor, S.O., and Schagerl, M. (2007). Temporal trends of ion contents and nutrients in three Kenyan Rift Valley saline-alkaline lakes and their influence on phytoplankton biomass. The International Journal of Aquatic Sciences, 584(1)59–68.

Ramakrishnaiah, C.R., Sadashivaiah, C., and Ranganna, G. (2009). Assessment of Water Quality Index for the Groundwater in Tumkur Taluk, Karnataka State, India. E-J. Chem., 6, 523–530.

Rajapaksha R.M.G.N., Dharmagunawardhane H.A., Attanayake A.M.A.N.B., & Rekha Nianthi K.W.G. (2020). Altitudinal and temporal variation of surface water quality: An assessment in Badulu Oya Catchment, Sri Lanka. GSC Biological and Pharmaceutical Sciences, 11(3), 226–234.

Saunders, J.F., III, and Lewis Jr, W. M. (1968). Transport of phosphorus, nitrogen and Carbon by the Apure River, Venezuela. Biogeochemistry 5:323-342.

Sazia, B., Pruthviraj, P., and Bablu, P. (2018). Ground Water Quality Index of Growing Smart City of Vadodara. Int J Environ Sci Nat Res. 2018; 9(2):555759.

Schagerl, M. (2016). Soda lakes of East Africa. Springer e-Books.

Seo, J., Won, J., Choi, J., & Kim, S. (2021). Identification of the Relative Importance of Factors Affecting the Spatial Variability of River Water Quality. Sustainability, 13(20), 11319.

Siqueira, T., da Silva, Pessoa, L.A., Vieira, L.C., Vivian de, M., Singh, S., Kumar. B.E., and Vitor C.E. (2023). Evaluating land use impacts on water quality: perspectives for watershed management. Sustainable Water Resources Management, 9(6), 1–24.

Sirje, V., Peeter, P., Haldna, M., Nõges, P., Piirsoo, K, and Nõges, T. (2024). How the catchment-river-lake continuum shapes the downstream water quality. Journal of Limnology, 83(1).

Shimba, M.J. (2017). Spatial and seasonal variations in surface water quality of the Mkondoa River, Tanzania. Journal of Soil Science and Environmental Management, Vol. 8(9):148-154.

Strahler, A,H., and Strahler, A.N. (2003). Introducing Physical Geography (3rd Ed). Wiley.Talling, J.F., and Talling, I.B. (1965). The chemical composition of African lake waters. Int. Revue Hydrobiol. 50(3):421-463.

Tilman, D., Kilham, S.S., and Kilham, P. (1982). Phytoplankton community ecology: The role of limiting nutrients. Ann. Rev. Ecol. Syst. 13:349-372.

Tiwari, T.N., and Mishra, M.A. (1985). A preliminary assignment of water quality index of major Indian rivers. Indian J. Environ. Prot. 1985, 5,276–279.

Uddin, M.G., Nash, S., and Olbert, A.I. (2021). A review of water quality index models and their use for assessing surface water quality. Ecological Indicators, 122.

Vannote, R.L., Minshall, G.W., Cummins, K.W., Sedell, J.R., and Cushing, C.E. (1980). The River Continuum Concept. Canadian Journal of Fisheries and Aquatic Sciences, 37(1), 130–137.

Vaseashta, A., Duca, G., and Travin, S.O. (2021). Handbook of research on water sciences and society, IGI Global.

Webster, J.R. (2007). Spiraling down the river continuum: stream ecology and the U-shaped curve. Journal of the North American Benthological Society, 26(3), 375–389.

Wohl, E.E. (2020). Rivers in the landscape: Science and management (2nd. Ed). Wiley-Blackwell.

World Health Organization, WHO (2017). Guidelines for drinking-water quality (4th edition incorporating the first addendum). World Health Organization.

Yang, E., Wang, Q., Zhang, Z., Shao, W., Luo, H., Xiao, X., Ni, F., Mi, J., Sun, X., and Guan Q. (2024). Source-oriented health risk assessment of heavy metals in a soil-river continuum in northwest China. International Journal of Sediment Research, 39(6), 916–928.

Zhang, J., Yang. Y., Yang, X., Qin, J., Wei, X., Peng, Y., Li, Z.L., Zhang, Z., and Zou. Y. (2021). Influence of manganese exposure on cognitive function, plasma APP and Aβ levels in older men. Journal of Trace Elements in Medicine and Biology: Organ of the Society for Minerals and Trace Elements (GMS), 67, 126788.