Morphologic Response of a River Channel to Sand Mining in River Tyaa, Kitui County, Kenya

Authors

  • Philip Gathogo Muiruri Department of Geography, Kenyatta University, Kenya, 43844, Nairobi
  • Joy A. Obando Department of Geography, Kenyatta University, Kenya, 43844, Nairobi
  • Ishmail O. Mahiri Department of Geography, Kenyatta University, Kenya, 43844, Nairobi

DOI:

https://doi.org/10.30564/jees.v2i2.1935

Abstract

Over 40 billion tons of sand is mined worldwide every year which is estimated to be higher than the natural replacement rates. In Kenya, the rate of sand mining is raising concerns over its environmental effects since it is not regulated. This paper presents findings on the geomorphic effects of sand mining in the ephemeral River Tyaa channel in Kitui County. The study adopts the concept of feedback response mechanism of a natural geomorphic system. Through purposive sampling River Tyaa was selected for the study, where rampant sand mining was reportedly taking place. Random sampling on the five sand mining sites identified came up with a representative site namely Kanginga on which systematic sampling was applied while collecting data at both the active and control sites. Data on channel width, depth and slope angles was obtained through physical measurements while data on quantity of sand mined was obtained from Mwingi Sand Mining Cooperative. Multiple logistic regression analysis was used to analyse data whereby the model compared active and control sites. Test results indicated that sand mining had significantly increased river channel’s width (O.R. =1.531), depth (O.R. =1.527) and slope angles (O.R. =1.634) at active mining sites compared to control sites as deduced from the respective Odds Ratios. It concluded that sand mining had altered channel’s morphology resulting to adverse environmental effects such as loss of riparian vegetation and channel incision. It recommended curbing of illegal sand mining through licencing operators and reducing quantity of sand mined by closing some mines. Furthers, it recommended monitoring through regular Environmental Impact Assessment (E.I.A) and Audit (E.A) to inform protection of the river system from degrading.

Keywords:

Channel incision, Ephemeral stream, Morphologic response, Sand mining, Sustainable development

References

[1] Rinaldi, M., Wyżga, B., Surian, N. Sediment mining in alluvial channels: physical effects and management perspectives. River Research and Applications, 2005, 21(7): 805-828. DOI: https://doi.org/10.1002/rra.884

[2] United Nations Environment Programme (UNEP). Sand, Rarer Than One Thinks. 2014.

[3] Milliman, D., Syvitski, M. Geomorphic/Tectonic Control of Sediment Discharge to the Ocean: The Importance of Small Mountainous Rivers. J. Geol., 1992, 100(5): 525-544.

[4] Kondolf, G.M. Hungry water: effects of dams and gravel mining on river channels. Environmental Management,1997, 21(4): 533-551.

[5] Kondolf, G.M., M.L. Swanson. Channel adjustments to reservoir construction and Instream gravel mining, Stony Creek, California. Environmental Geology and Water Science, 1993, 21: 256-269.

[6] Rajesh, S., Anushiya, S. Report on state of Sand mining at Peri-Urban Kathmandu Case of Jhaukhel VDC.pdf. Nepal Engineering College, 2013.

[7] Khan S., Sugie A. Sand Mining and Its Social Impacts on Local Society in Rural Bangladesh: A Case Study of a Village in Tangail District. Journal of Urban and Regional Studies on Contemporary Issues. The Center for Contemporary India Studies, Hiroshima University, 2015.

[8] Collins, B., Dunne, T. Fluvial geomorphology and river gravel mining: a guide for planners, case studies included. California Division of Mines and Geology Special Publication 98, Sacramento, California.

[9] Kondolf, G.M. Geomorphic and environmental effects of instream gravel mining. Landscape and Urban Planning, 1990, 28: 225-243.

[10] Kondolf, G.M. Environmental effects of aggregate extraction from river channels and Floodplains. Rotterdam, 1998: 113-129.

[11] Leopold, L.B., M.G. Wolman, J.P. Miller. Fluvial Processes in Geomorphology. Freeman, San Francisco, CA, 1964.

[12] Akot T., Onoduku U., Oke S., Essien B., Idris F., Umar A., Ahmed A. Environmental Effects of Sand Mining and Grvel Mining on Land and Soil in Luku, Minna, Niger State, North Central Nigeria. Journa of Geosciences and Geomatics, 2014, 2(2): 42-49.

[13] Atejioye A.A. Odeyemi C.A. Analysing Impact of Sand Mining in Ekiti State, Nigeria using GIS for Sustainable Development. World journal and of Research and Review (WJRR), ISSN: 2455-3956. 2018, 6(2): 26-31.

[14] Nabegu, A. B. Morphologic Response of a Stream Channel to Extensive Sand Mining. Research Journal of Environmental and Earth Sciences, 2014, 6(2): 96- 101.

[15] Madyise, T. Case studies of environmental impacts of sand mining and gravel extraction for urban development in Gaborone, 2013.

[16] Muiruri P.G. Amimo M.O. Social-Environmental Effects of River Sand Mining: Case Study of Ephemeral River Kivou in Kitui County, Kenya. International Organization of Scientific Research, Journal of Humanities and Social (IOSRJHSS), 2017, 22: 31-37.

[17] Mwaura, S. K. The Effects of Sand Harvesting on Economic Growth in Kenya with case study of Machakos County. International Journal of Social Sciences and Entrepreneurship, 2013(5): 342-350.

[18] Wambua M. P. Environmental and socio-economic impacts of sand Harvesting on the community in river Kivou catchment, Mwingi Sub-County, Kitui County, Kenya. Unpublished M.A. Thesis. Kenyatta University, 2015.

[19] Mutisya, D. N. Sand harvesting and its environmental and socioeconomic Effects in arid and semi-arid Kenya. P. World Assoc. Soil Water Conserve. 2006, PI: 82-90.

[20] Huggett, R. J. Fundamentals of Geomorphology (2. ed). London: Routledge, 2007.

[21] United Nations. Consensus Reached on New Sustainable Development Agenda to Be Adopted by the World Leaders in September. 2 august 2015 [online]. Available at: http://www.un.org/sustainabledevelopment/blog/2015/08/transforming-our-world-document-adoption/ [accessed 20 may 2016].

[22] Nyamai, C. M., Mathu, E. M., Opiyo-Akech. N., Wallbrecher. E. A Re-appraisal of the Geology, Geochemistry, Structures, and Tectonics of the Mozambique belt in Kenya, East of the Rift System. African Journal of Science and Technology (AJST), 2003, 4: 51-71.

[23] Nissen, P. Rain catchment and water supply in rural Africa. London: Hodder and Stoughton, 1982.

[24] Pulfrey W. Geological Survey Report of Kenya, Nairobi, 1954.

[25] GOK. Government of Kenya. The 2009 Kenya National Census Results. Ministry of Home Affairs, Nairobi, Kenya, 2010.

[26] Brown, A.V., M.M. Lytte and K.B. Brown. Impacts of gravel mining on gravel bed streams. T. Am. Fish. Soc., 1998, 127: 979-994.

[27] Kim, A., Song, Y., Kim, M., Lee, K., Cheon, J.H. Logistic regression model training based on the approximate homomorphic encryption. IACR Cryptology. ePrint archive, 2018.

[28] AMPONSAH-Dacosta, F., Mathada, H. Study of Sand Mining and Related Environmental Problems along the Nzhelele River in Limpopo Province of South Africa. Journal of Mine Water and Circular Economy, 2017.

[29] Nabegu, A. B. The effect of sand mining on ground water in Kano river catchment Journal of Environment and Earth Science, 2013, 3(2): 2224-3216.

[30] Surian N, Rinaldi M. Morphological response to river engineering and management in alluvial channels in Italy. Geomorphology, 2003, 50: 307-326.

[31] Marston R. A, Bravard J-P, Green T. Impacts of reforestation and gravel mining on the Malnant River, Haute-Savoie, French Alps. Geomorphology, 2003, 55: 65-74.

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How to Cite

Muiruri, P. G., Obando, J. A., & Mahiri, I. O. (2020). Morphologic Response of a River Channel to Sand Mining in River Tyaa, Kitui County, Kenya. Journal of Environmental & Earth Sciences, 2(2), 12–18. https://doi.org/10.30564/jees.v2i2.1935

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