Analysis of Land Use Change and Its Impact on the Hydrology of Kakia and Esamburmbur Sub-Watersheds of Narok County, Kenya

Abstract

Narok town is one of the places in Kenya which experience catastrophic floods. Many lives have been lost and valuable property destroyed in recent years. Change in land use/land cover upstream of the town area may have contributed significantly to the severity and frequency of flooding events. Runoff, which contributes to floods in Narok town, comes from Kakia and Esamburmbur sub-catchments of Enkare Narok watershed. The objective of this study was to assess the impact of land use/land cover change on the hydrology of Kakia and Esamburmbur sub-watersheds. To detect land use/land cover change, Landsat satellite images from 1985 to 2019 were used. Using supervised classification in Erdas Imagine 2014, land use of the study area was classified into four classes, i.e., forest, rangeland, agriculture and built-up areas. Five land use maps (1985, 1995, 2000, 2010, and 2019) were developed and used to perform land use change analysis. There was rampart conversion of forest to other land uses. Between 1985 and 2019, the forest and rangeland declined by 40.3% and 25.6% of the study area, respectively, while agriculture and built-up areas increased by 55.2% and 10.6% of the study area respectively. Analysis of soil hydrological properties indicate that the infiltration rate and soil hydraulic conductivity were greatest in forest than in other land use types. The basic infiltration rate in forest land was 89.1 cm/h while in rangeland and agricultural land, it was 7.9 cm/h and 15 cm/h respectively. At the top-soil layer, average soil hydraulic conductivity under forest was 46.3 cm/h, under rangeland, 2.6 cm/h and under agriculture, 4.9 cm/h. The low hydraulic conductivity in rangeland and agriculture was attributed to compaction by farm machinery (tractors) and livestock respectively. An interesting observation was made in rangelands where the top layer (0–20 cm) had a higher bulk density and a lower hydraulic conductivity as compared to the next deeper layer (20–40 cm). This was attributed to the combined impact of compaction and localised pressure by hooves of livestock which only have an impact on the top layer. The findings of this study show that land use has a major impact on soil hydrological properties and imply that the observed land use changes negatively affected the soil hydrological properties of the watershed. The decreased infiltration in the increasing areas of degraded land (mainly agriculture and rangeland) and increase in built-up area in Narok town are the possible causes of the increased flood risk in Narok town. It is recommended that flood risk management strategies in Narok town include watershed management to enhance water infiltration.

Land Use/Land Cover Change Impact on Hydrological Process in the Upper Baro Basin, Ethiopia

“…Land Use/Land Cover (LU/LC) change is one of the factors that directly affect the watershed hydrological cycle [3][4][5]. It has been widely accepted that human activities cause LU/LC change and have imposed a great impact on the hydrological processes and water resources of the watershed [6] For example, a study [1] showed that the water provision and the hydrological process decreased as consequence LU/LC change that was aggravated by significant increasing population pressure and development in Pennar Basin in India.…”

The impact of land use and land cover change on hydrological processes in Brantas watershed, East Java, Indonesia

“…Researchers usually study LULCC by investigating two or more maps produced at different times, for example, the work of Ptak & Ławniczak, 2012;Marie Mireille et al, 2019). Conventional maps and satellite images can be interpreted to study the causal effects of LULCCs and their implications for society and the environment (Kang et al, 2019).…”

“…The use of Landsat imagery to study LULCC is a widely known method and has been published in research reports worldwide (e.g. Lamichhane & Shakya, 2019;Marie Mireille et al, 2019;Al-Jiboori et al, 2020). LULCC may have positive and/or negative impacts on hydrological processes.…”

“…SWAT can analyse the impacts of climate, soil, vegetation and agricultural activities on river flow, and researchers worldwide have used it to study the impact of LULCC and CC on hydrological processes, for example the work carried out by Lamichhane and Shakya (2019) in Nepal. A similar study has been conducted by Mireille et al (2019) in Kenya, and Kang et al (2019) have applied SWAT and statistical methods to evaluate the effects of climate and land use change on surface hydrology in the Loess Plateau hilly-gully region of China.…”

The Influence of Soil Conditioning on Soil Infiltration Rate in Urban Facilities

“…All processes related to defect in the earth's surface are influenced by human activities, which are responsible for the landform changes, especially during the environmental planning that involves public policies (Sucahyanto et al, 2018). The global development of urban areas due to an increase in population has continuously threatened natural dynamics, the availability of resources, and environmental quality (McGrane, 2016; Marie Mireille et al, 2019). Moreover, changes in land cover have caused some problems such as soil degradation which depends on intensity, pattern, and types of land cover change, namely depletion of nutrients, decrease in infiltration capacity and moisture content of the soil (Marie Mireille et al, 2019).…”