Micro Watershed Development Using GIS & Remote Sensing in the Case of Chille and Ocholo Watersheds, Duguna Fango Woreda, Wolaita Zone, Southern Nations Nationalities and Peoples Region, Ethiopia

Abstract

This study analyses micro watershed development using the techniques of GIS and Remote Sensing in order to delineate the areas of Chille and Ocholo micro watersheds, generate their base map and development map. Watershed development is the approach best suited to address the sustainable use and management of resources. In Ethiopia, large-scale watershed development has been limited. In the country at large and the study area, Duguna Fango Werda, in particular is currently facing numerous environmental problems resulted from inappropriate agricultural practice and exploitation of natural resource base. Scarce vegetation cover associated with erosion induced factors exposing the study area to high rates of soil erosion and loss of soil fertility that initiated the researcher to conduct this study in this area.Data were collected from sources such as, SRTM-DEM and Satellite Image with row 55 and path 169 full scene of the year 2017 downloaded from USGS; Google earth image; Shape file of the SNNP Regional State; GPS reading point data from the study area and physical observation of the area studied. Materials used to effectively execute this research include Global Mapper 11, ArcGIS10.3 and ERDAS Imagine 2014. Land use/cover classifications were generated through image classification of Landsat ETM+5 satellite imagery using ERDAS Imagine 2014softwareand mapped using ArcGIS10.3. The Zonal toposheet maps of the scale 1:50,000 and 20meter spatial resolution SRTM DEM was used to produce the location map and delineate area of the watersheds. Landsat ETM+5 satellite imagery of the study area having 30meter spatial resolution was used for base map production and development map.The area of Chille Micro Watershed is 468.8 Hectares whereas that of Ocholo is 309.3 Hectares. Chille Micro Watershed covers wider extent than that of Ocholo.Major land cover of Chille watershed, constituting 27.7percent or 129.3 hectare, is degraded land followed by 22.6percent or 105.6 hectare farmland. Its least proportion is human settlement and forest land that constitute 37.3hectare or 8percent and 32.1 hectare or 6.9percent land cover respectively. The majority, 30.5percent or 94.2 hectare, of Ocholo Micro Watershed is degraded land followed by 23.5percent or 72.5 hectare farmland. This watershed has the least proportion of 19.4hectare or 6.3percent forest cover preceded by 22.7hectare or 7.3percent of human settlement. The largest land use proportion of both Chille and Ocholo Micro Watersheds is degraded land followed by farmland while their least proportion is human settlement and forest cover. For the development of both Chille and Ocholo watersheds, the proposed conservation strategies include bench terrace, deep trench, stone bund and hill side terrace for degraded land. Faniyajuu, soil bund, trench, bench terrace, and cut off drains for the farm land areas; cut & carry system, cut off drain, deep trench area closure for the grasslands; plantations of trees, SWC methods such as trench for bush land; and area closure for the protection of the limited forest coverage found in the micro watersheds.

Keywords: GIS & Remote Sensing, Micro watershed, watershed development, base map generation, development map production