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Research Article Open access CC BY 4.0

Analysis of Rainfall Variability and Trends Over Nzoia River Basin, Kenya

Ernest Othieno Odwori, Jacob Wanambacha Wakhungu

Journal of Engineering Research and Reports · pp. 26–52 · Published 5 Nov 2021

10.9734/jerr/2021/v21i417457

Abstract

Nzoia river is mainly rain fed and the basin is one of the regions that is highly vulnerable to climate change in Kenya. Understanding rainfall variability and trends is important for better water resources management and economic development in the basin. The aim of this study is to assess variability and trends in rainfall at 13 sites within Nzoia River Basin over the period, 1970 to 2001, using the parametric test of Linear regression analysis and the non-parametric Mann–Kendall statistical test. Data for this study was obtained from the Kenya Meteorological Department (KMD). The basin experiences four rainfall seasons in a year as a result of the Inter-Tropical Convergence Zone (ITCZ). There are two rainy seasons and two dry seasons. Annual rainfall through Linear regression analysis shows 6 stations, Kaimosi Tea Estate Ltd, Kakamega Meteorological Station, Bungoma Water Supply, Nzoia Forest Station, Malava Forest Station and Webuye Agricultural Office with declining rainfalls. The remaining 7 stations, Leissa Farm Kitale, Turbo Forest Nursery, Chorlim ADC Farm, Kaptagat Forest Station, Kimilili Agricultural Department, Bunyala Irrigation Scheme and Kadenge Yala Swamp showed increasing rainfalls. The majority of stations with increasing annual rainfall are in the upper catchment whereas those with decreasing rainfall are in the middle and lower catchment. Only 3 out of the 13 stations showed statistically significant trends in rainfall with two in the upper catchment and one in the middle; the remaining 10 stations had statistically insignificant trends. These observed changes in rainfall, although most time series are not convincing as they show predominantly no significance, along with the reported climatic warming in most parts of the basin may have future implications on human health, water resources management, various plant and animal species bio-diversity and the overall economic development of the basin.

Nzoia river basin rainfall variability and trends linear regression analysis Mann-Kendall statistical test

References (49)

  1. 1 Nonparametric Tests Against Trend [DOI]
  2. 2 Global observed changes in daily climate extremes of temperature and precipitation [DOI]
  3. 3 Analysis of changes in meteorological variables using Mann-Kendall and Sen's slope estimator statistical tests in Serbia [DOI]
  4. 4 Statistical Methods for Environmental Pollution Monitoring. [DOI]
  5. 5 Estimates of the Regression Coefficient Based on Kendall's Tau [DOI]
  6. 6 African climate change: 1900-2100 [DOI]
  7. 7 Nonlinear Time Series: Nonparametric and Parametric Methods [DOI]
  8. 8 Climate change and changes in global precipitation patterns: What do we know? [DOI]
  9. 9 On the Statistical Analysis of Series of Observations
  10. 10 Analysis of long-term rainfall trends in India [DOI]
  11. 11 Precipitation Climatology in an Ensemble of CORDEX-Africa Regional Climate Simulations [DOI]
  12. 12 Precipitation measurements and trends in the twentieth century [DOI]
  13. 13 A westward extension of the warm pool leads to a westward extension of the Walker circulation, drying eastern Africa [DOI]
  14. 14 Rainfall trends in arid and semi-arid regions of Iran [DOI]
  15. 15 A recent and abrupt decline in the East African long rains [DOI]
  16. 16 A Review of Climate Dynamics and Climate Variability in Eastern Africa [DOI]
  17. 17 An Analysis of Recent Rainfall Conditions in West Africa, Including the Rainy Seasons of the 1997 El Niño and the 1998 La Niña Years [DOI]
  18. 18 On climate variability in Northeast of Brazil [DOI]
  19. 19 Projected Changes in Mean and Extreme Precipitation in Africa under Global Warming. Part II: East Africa [DOI]
  20. 20 Change detection in hydrological records— a review of the methodology
  21. 21 A global perspective on African climate [DOI]
  22. 22 Trends in total rainfall, heavy rain events and number of dry days in Australia, 1910–1990 [DOI]
  23. 23 Rainfall and Water Resources Variability in Sub-Saharan Africa during the Twentieth Century [DOI]
  24. 24 Trend detection of annual and seasonal rainfall in Calabria (Southern Italy) [DOI]
  25. 25 Evaluation of the CORDEX-Africa multi-RCM hindcast: systematic model errors [DOI]
  26. 26 Trends in seasonal and annual rainfall and rainy days in Kashmir Valley in the last century [DOI]
  27. 27 Reduced Interannual Rainfall Variability in East Africa During the Last Ice Age [DOI]
  28. 28 Temporal and spatial variations of precipitation in Northwest China during 1960–2013 [DOI]
  29. 29 Recent climate trends and implications for water resources in the Catskill Mountain region, New York, USA [DOI]
  30. 30 An analysis of the tendency of reference evapotranspiration estimates and other climate variables during the last 45 years in Southern Spain [DOI]
  31. 31 Future changes in rainfall associated with ENSO, IOD and changes in the mean state over Eastern Africa [DOI]
  32. 32 Climate change and coastal cities: the case of Mombasa, Kenya [DOI]
  33. 33 Recent trends in mean maximum and minimum air temperatures over Spain (1961–2006) [DOI]
  34. 34 Rainfall variability in southern Spain on decadal to centennial time scales [DOI]
  35. 35 Precipitation in Nepal between 1987 and 1996 [DOI]
  36. 36 Teleconnection responses in multi-GCM driven CORDEX RCMs over Eastern Africa [DOI]
  37. 37 Climatic Change - Implications for India’s Water Resources [DOI]
  38. 38 On the Fine-Scale Topography Regulating Changes in Atmospheric Hydrological Cycle and Extreme Rainfall over West Africa in a Regional Climate Model Projections [DOI]
  39. 39 Analysis of rainfall climate on the Njemps Flats, Baringo District, Kenya [DOI]
  40. 40 Seasonal and Spatial Patterns of Rainfall Trends on the Canadian Prairies* [DOI]
  41. 41 An assessment of the role of homogenization protocol in the performance of daily temperature series and trends: application to northeastern Spain [DOI]
  42. 42 Iso-radiation maps for tilted surfaces in the Castile and Leon region, Spain [DOI]
  43. 43 Reconstruction of six decades of daily total solar shortwave irradiation in the Iberian Peninsula using sunshine duration records [DOI]
  44. 44 Subseasonal climate variability for North Carolina, United States [DOI]
  45. 45 Precipitation measurements and trends in the twentieth century [DOI]
  46. 46 Defining Intraseasonal Rainfall Variability within the North American Monsoon [DOI]
  47. 47 Diurnal temperature range trend over North Carolina and the associated mechanisms [DOI]
  48. 48 Measurements and attenuation of erythemal radiation in Central Spain [DOI]
  49. 49 Intergovernmental Panel on Climate Change [DOI]

Cited by 3

Temperature Variability and Trends in Nzoia River Basin, Kenya

Ernest Othieno Odwori · Asian Journal of Geographical Research · 2021

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