Soil and water conservation (original) (raw)
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UTTAR PRADESH JOURNAL OF ZOOLOGY, 2022
Soil erosion in Ethiopia exacerbates land degradation, desertification, the decline in productivity, and drought and affects farmers' livelihoods. Therefore, this study aimed to estimate annual soil loss in southern Ethiopia, North-Bilate watershed. For this purpose, the land-based ETM image was divided into seven classes using Erda's Imagine 10.5. Soil, topography, and precipitation data were also obtained from various sources and analyzed in Arc GIS 10.8. Accordingly, five factors (soil erosivity, erodibility, topography, cover management, and support practice) were calculated in ArcGIS 10.8 using the RUSLE model to estimate annual soil loss. As a result, 537035.13 ha (96.1%) and 16521.21 ha (3.1%) of the watershed showed very little and little water erosion, respectively. As can be seen, about 99% of the watershed area had a lower (0.64.73 t/ha/year) risk of soil erosion, while the remaining 1% of the watershed area had a moderate to extreme soil erosion state; which remove a large amount (64.73 1500 t/ha/year) of a clay soil from the riverbanks and muddy areas, mainly from upstream of the Bilate River (the largest in the watershed); due to the maximum slope length and steepness and the rapid flow of water. In conclusion, areas with higher rainfall intensity, active human intervention, lots of sandy soil content, sloppy topography, and thinner soil depth are collectively degraded and prone to erosion. Therefore, such vulnerable areas should mitigate their risk by using organized soil and water conservation techniques to conserve the watershed's total land resources. Physical measures such as terracing and dams should be implemented. In addition, to preserve and increase the biodiversity of the study area, the planting of various types of native vegetation and plantation tree species should be carried out with a viable afforestation and reforestation program.
A watershed is defined as any surface area from which runoff resulting from rainfall is collected and drained through a common confluence point. Now a day's, with the increasing population watershed degradation is a serious problem in developing countries like Ethiopia. Amhara Regional state is potential for agricultural production for the country. The region is now affected by land degradation. Antsokiya Gemiza is one of the potential woreda in the North Shewa Zone but the woreda is now become under immense threat of agricultural productivity reduction. Land degradation is the main cause of decline in productivity of land, low income of the people. Natural resource depletion by sever soil erosion and environmental mishaps eroded the confidence of farmers living in the high rainfall and productive regions. Antsokiya Gemiza woreda is one of those areas considered as agricultural potential areas. For sustainably develop this high agricultural potential and labor available area, priority should be given to natural resources, especially soil and water conservation, based and economically feasible development projects. For that matter, investment on irrigation projects will increase crop production and reduce natural hazard risks. Therefore, construction of small-scale irrigation project is significantly important for the area. Bishano small-scale irrigation project watershed is found in Antsokiya Gemiza wereda of North Shewa Zones of Amhara Regional State. Land degradation assessment study carried out at Bishano watershed at Antsokia Gemiza woreda in Amhara Regional State. The study has to assess land characteristics related to land degradation for watershed management project study. The study was based on overlay of soil geomorphology; climatic, present lands cover processed in Arc.GIS 9.3 environments and analyze physical land resources, social implications and economic benefits. The general objective of the Bishano intake irrigation watershed management plan study is to identify, understand ecological and socio-economic problems in the watershed and prepare the watershed intervention plan that enable sustainable management and use of resource; there by establishing long-lasting irrigation water supply system while improving livelihood of the communities in the watershed through creating and sustaining improved agricultural production systems and land productivity. The methodology employed includes collection of primary and secondary data at field level .The study approaches and procedures exercised during different stages of the study include pre-field work, fieldwork, and post fieldwork activities. Bishano irrigation project watershed, has an area of 1489.05 ha is located in Amhara National Regional State North Shewa zone Antsokiya Gemiza and Menz Mama Midr weredas. The watershed has an altitudinal range from 1763 to 3096 m.a.s.l. The Watershed has only one dry weathered feeder road join from kebele to woreda town. Four types of soils have been identified in the watershed namely: Eutric Cambisol, Eutric Regosols, Lithosols and rock surface. The dominant textures identified in this watershed are loam, clay loam and clay. All types of slopes are present in the watershed. It has about 1018.2mm/yr annual rainfall. The annual average maximum temperature is estimated at 28.65oC. The total population of watershed is about 14,287 in number. The farming system comprises field crop production, livestock rearing and tree growing. The major crop types cultivated in the watershed are Teff, sorghum and maize. The dominant trees grown in the watershed include Cordia Africana, Ficus Spps and Eucalyptus. Soil degradation is decline of organic matter, depletion of nutrient, salinization and drying up of rivers and lakes .The common type of erosion is water erosion exhibited with all forms of erosion such as sheet and rills, gully, stream bank and land sliding on very steep slope areas. To assess soil erosion hazard for project area the revised universal soil loss equation (RUSLE) approach was followed. The land degradation map was developed on Arc GIS environment by using RUSLE parameters (rainfall erosivity; soil erodibility; slope length and gradient; land cover; and land management practices) as an input to assess average annual soil loss rate of the area. Based on the analysis, the total amount of soil loss in the watershed is about 25.3 ton/ha/year in mountains and hilly areas and 0.52 ton/ha/yr at flat and level areas where deposition takes place, the mean annual soil loss is 6.86 tons/ha/yr. From the assessment, 45.08% of the area has soil loss below the mean value. About 91.58 % of the area non-to slight and 8.42% moderate soil loss class. In order to alleviate the problems, the study identified and presented different mitigation measures in the main body of the report.
Land use and land cover changes and Soil erosion in Yezat Watershed, North Western Ethiopia
Biomass GIS NDVI Land-use and land-cover Remote sensing RUSLE a b s t r a c t Soil erosion affects land qualities and water resources. This problem is severe in Ethiopia due to its topographic features. The present research was aimed to estimate spatiotemporal changes in land-use/ land-cover pattern and soil erosion in the Yezat watershed in Ethiopia. This study was carried out by using landsat imageries of 2001, 2010 and 2015. Images were classified into categories using supervised classification by maximum likelihood algorithm. They were also classified into different biomass levels by using Normalized Difference Vegetation Index (NDVI) analysis. Revised Universal Soil Loss Equation modeling was applied in a GIS environment to quantify the potential soil erosion risk. The area under grassland, woodland and homesteads have increased by 610.69 (4%), 101.69 (0.67%) and 126.6 ha (0.83%) during 2001-2015. The extent of cultivated land and shrub/bushland was reduced by 323.43(0.02%) and 515.44 ha (3.41%), respectively, during the same period. The vegetation cover in the watershed decreased by 91% during 2001-2010, and increased by 88% during 2010-2015. Increase of NDVI values indicates better ground cover due to implementation of integrated watershed development program in the region. The estimated annual soil losses were 7.2 t ha À 1 yr À 1 in 2001, 7.7 t ha À 1 yr À 1 in 2010 and 4.8 t ha À 1 yr À 1 in 2015. Management interventions are necessary to improve the status and utilization of watershed resources in response to sustainable land management practices for sustainable livelihood of the local people.
2020
Characteristics of watershed were not well investigated as global also in Fincha, Ethiopia. Fincha watershed is the most erosion prone area in the highlands of Ethiopia towards to Fincha dam.Therefore, the aim of this study was toanalysisFincha watershed characteristics based on land use/cover, soil type and slope classification and to identify soil erosionpronearea using Arc-GIS and Arc-SWAT model.Accordingly, nine major land use/covers were identified. Those were:- bush land, dominantly cultivated, moderately cultivated, irrigated land, grass land, water bodies, swamp area, urban and woodland open. From these most part of the catchment was under cultivation with 67.677% of the total area. In the same way, the major soil types identified were: - chromic luvisols, chromic vertisols, dystric cambisols, eutric cambisols, eutric nitosols, eutric regosols, haplic phaeozems, humic cambisols and water. Cambisols were covered the highest percentage, 39.98% area of the catchment.Subsequentl...
Soil erosion is being detected as a risk to human survival by diminishing the food and water availability of the planet Earth in the 21 st century. Assessment and management of this resource are becoming extremely important. This study aimed to investigate Soil Erosion Risk and Prioritize for soil and water conservation measures in the study area. Satellite data, SRTM DEM, Land sat 8 OLI with 30m resolution; rainfall and soil data were used to generate all soil erosion risk factor maps and integrated to generate a composite map of soil loss for the watershed. The RUSLE model in combination with remote sensing and GIS techniques was used to identify the five thematic maps as an input to estimate mean annual soil loss. The results of the spatial distribution of soil erosion risk factors indicated that rainfall erosivity, soil erodibility, slope length and steepness, cover management, and anthropogenic soil erosion control practices values ranged from 41.365 to 43.793MJ mm ha −1 yr −1 , 0.26 to 0.31t ha −1 MJ −1 mm −1 , 0 to 220.512, 0.21 to 0.87 and 0.11 to 1 respectively. And the most powerful factor that influences soil erosion risk is topography followed by anthropogenic soil erosion control practices. The results of the study showed that the annual soil loss rate in the watershed ranged from 0 in gentle slopes to 1504 t ha-1 yr-1 at the steepest slope of the watershed with a mean annual soil loss of 48.5 t ha-1 yr-1 at Midhagdu watershed level. The soil loss map was categorized into five soil loss numerical ranges and soil loss risk nominal scales: low, moderate, high, very high, and extremely high using Ethiopian highland maximum soil loss threshold level 18 t ha-1 yr-1. The soil loss risk levels identified at 28 micro watersheds showed that twelve micro watersheds rated as first, eleven micro watersheds as second, and three micro watersheds as the third priority for soil and water conservation measures implementation. Out of 28 micro watersheds, 26 fell above Ethiopian highland maximum soil loss threshold levels. Therefore, the study result indicated that the Midhagdu watershed needs immediate intervention for better for soil and water conservation measures implementation planning by considering identified soil erosion risk areas and priority classes to control soil erosion risk below the national threshold level.
Soil loss through water is one of the major environmental problems leading to land degradation worldwide. Though soil erosion is an inevitable natural phenomenon, it is possible to reverse and minimize the rate at a local level. This requires spatially unambiguous evidence on rate of soil loss so as to implement site specific land management decisions. The aim of this study was to estimate the mean annual soil loss and optimize land management measures in the Midhagdu watershed of western Hararghe highlands, Ethiopia. The study used five soil loss factors as input variables to estimate the soil loss. A thematic layer map was generated for each factor with spatial resolution of 30 m using Geographical Information System (GIS), and combined them with revised universal soil loss equation (RUSLE) model to estimate soil loss and identify erosion risky area in the watershed. According to the results, the distribution of annual soil loss varied between 0 and 179 t ha − 1 yr − 1 , with a mean annual loss rate of 44.24 t ha − 1 yr − 1. The total annual soil loss in the entire watershed was 240,250 tons. Of this, 93.48% (224,593 tons) of the loss occurred in 49% (2,674 ha) of the catchment area,which was above the maximum tolerable soil loss limits. Most of the soil erosion affected areas are spatially situated in the upper and hillsides of the watershed. This is due to factors attributed to the steepness of the slope, dominance of Leptosols with shallow soil depth, coupled with absence of supporting practice in these parts of the watershed. Thus, slope length and slope steepness (LS) factor was the primary RUSLE parameters that controlled the soil loss in the studied watershed followed by soil erodibility (K) and support practice (P) factor. Hence, this study optimized land management options for future intervention based on the inherent limitation of the biophysical environment, socioeconomic and cultural conditions of the watershed community.
Assessment of soil loss rate using GIS–RUSLE interface in Tashat Watershed, Northwestern Ethiopia
Journal of Sedimentary Environments, 2022
The erosion of soil is one of the most difficult and ongoing problems caused by deforestation, improper cultivation, uncontrolled grazing, and other anthropogenic activities. As a result, assessing the level and quantity of soil erosion is essential for agricultural productivity and natural resource management. Thus, the goal of this study was to quantify soil loss rates and identify hotspot locations in the Tashat watershed, Abay basin, Ethiopia. Thematic factor maps, comprising rainfall erosivity factor (R), soil erodibility factor (K), topography factor (LS), cover and management factor (C), and conservation practices factor (P), were integrated using remote sensing data and the GIS 10.3.1 environment to estimate soil loss using RUSLE. The findings indicated that the watershed annual soil loss varies from none in the lower part to 3970.6 t ha −1 year −1 in the middle, with a mean annual soil loss of 64.2 t ha −1 year −1. The total estimated annual soil loss was 61,885,742.9 tons from the total watershed area of 48,348.4 ha. The majority of these soil erosion-affected places are geographically located in the watershed middle steepest slope portion, where Cambic Arenosols with higher soil erodibility character than other soil types in the research area predominate. Thus, sustainable soil and water conservation techniques should be implemented in the steepest middle section of the study area by respecting and acknowledging watershed logic, people, and watershed potentials.
Environmental Systems Research
Background: Water induced soil erosion has been continued to threaten the land resources in sub humid northwestern highlands of Ethiopia. Soil and water conservation measures have been implemented without site-specific scientifically quantified soil erosion data and priority bases. In this regard, quantitative analysis of soil erosion and its spatial variation plays a decisive role for better evidence and priority based implementation. Thus, this study aimed to estimate potential soil loss, identify hotspot areas, and prioritize for conservation measures in Gumara watershed using RUSLE, GIS and remote sensing techniques'. Result: The study result showed that soil loss due to water erosion was found to be a critical problem in the watershed. It ranges from nearly zero in gentle slope of forest lands to 442.92 t ha −1 year −1 on very steep slope cultivated lands. A total of 9.683456 million t of gross surface soil has been lost annually, with an average soil erosion rate of 42.67 t ha −1 year −1. Of which 62.1% was generated from cultivated land. The model result indicated a high spatial variability of soil erosion within the watershed. High intensity of soil erosion has been principally attributed to slope and land use/covers. The study further estimated that about 63.1% of the total soil loss was generated from only 29.3% of the area delineated as very severe soil erosion severity class. Soil erosion rate for 71.7% of the watershed area was beyond the maximum tolerable soil erosion limit estimated for Ethiopian highlands (> 18 t ha −1 year −1). The subwatershed severity class map revealed that 3814 ha of the sub-watershed area was evaluated as very severe level of soil erosion severity class. Conclusion: Soil erosion in the watershed has been a threatening problem for agricultural production to day, its sustainability and to be worsening in the future unless remedial measures were taken, mainly due to human intervention. Therefore, Gumara watershed needs immediate intervention for better conservation planning by considering identified priority classes and hotspot areas.
International Journal of Water Resources and Environmental Engineering, 2019
Soil erosion is the most challenging and continuous environmental problems resulting in both on-site and off-site effects in the world particularly in Ethiopia. Karesa watershed is one of the most erosionprone watersheds which received little soil conservation attention. This study was conducted to estimate average annual soil loss rate using Geographic Information System and Universal Soil Loss Equation Model adapted to Ethiopian condition. The following datasets were obtained from different sources for estimating annual soil loss such as 15 years mean annual rainfall data for estimating erosivity factor, digital soil map for estimating soil erodibility factor, 30 m × 30 m resolution Digital Elevation Model for estimating slope length and slope steepness (LS) factor, Landsat6ETM+ images with 30 m × 30 m resolution for detecting vegetation cover and conservation practice factor. The result reveals that 42,413.72 ton per year soil loss from 9939 ha entire watershed or 4.27 tons per hectare per year average annual soil loss rate was observed. The mean annual soil loss rate was classified into four erosion severity classes as very less, less, moderate and high. The result also implies that 94.4% (9383.07 ha) of the watershed areas contributes 81.13% of the total soil loss which were observed from two slope classes (0-15% and 15-30%) and categorized under very less to less soil loss (0-6.25 tons ha-1 yr-1). On the other hand, moderate to high soil loss (6.25-25 tons ha-1 yr-1) was obtained on slope classes of >30% which covers 555.93 ha (5.6%) of the watershed areas and contributes 18.82% of the total soil loss indicating the maximum share of slope mainly due to cultivation of marginal land,intensive cultivation, poor vegetation cover during critical rainfall period. Moreover, about 2,184.93 ha of the watershed area requires integrated soil and water conservation measures.
ournal of Soil Science and Environmental Management Vol. 1 (8), pp. 184-199, November, 2010 Available online at http://www.academicjournals.org/JSSEM ISSN 2141-2391 ©2010 Academic Journals (PDF) , 2010
The soils of the Delbo Wegene watershed of Southern Ethiopia were characterized along toposequence for the development of land management plan for sustainable soil management practices. Four pedons along toposequence were studied. Delbo Wegene watershed is located between 06°52' 45.9'' and 06°53'34.8'' N latitude and between 37°48' 10.5'' and 37°48'42.4''E longitude, with altitude ranging from 2100 to 2300 m.a.s.l. The soils were generally dark reddish brown to very dark brown and very deep (> 150 cm). The overall friable consistency, low bulk density (1.0 to 1.26 gm/cm 3), sub angular to angular blocky structure, high total porosity (53 to 61%) indicated that the soils have good physical condition for plant growth. The soils were slightly (pH: 5.8) to moderately acidic (pH: 6.4). Organic carbon content, available micronutrients and cation exchangeable capacity of the soils decrease with soil depth. However, exchangeable cations increase with increasing soils depth. Available phosphorus content of the soils ranged from very low to high. However, available Cu content of the soils were marginal to deficient. The upper and middle pedons with argilic subsurface horizons were classified as Typic Paleustults (Soil Survey Staff, 1999). These soils correlate with Cutanic Luvisols (WRB, 2006). The lower and toe slope pedons with mollic epepedon and cambic subsurface horizon were classified as Typic Haplustepts. These soils correlate with Haplic Cambisols (WRB, 2006). The result indicated that the distribution and properties of the soils vary along the toposequence in the watershed.