Gully Morphology and Gully Erosion Control in Calabar, Cross River State, Nigeria

Abstract

Gully erosion is a highly visible form of soil erosion that results in large volume of soil and sediment transport. Gully processes have a three dimensional nature that are affected by a wide array of factors and processes which include topography, soils, land use and climatic events. In this study the four major Gully erosion sites in Calabar including Ikot Efangha Mkpa, Bebobsco, Inyang Ansa (Atimbo) and Winners, present case studies scenarios. Morphological parameters of the gullies including length, width, depth, slope, area e.t.c were determined from GPS and Total Station Surveys. Meteorological data were obtained from meteorological station in Calabar while soil characteristics for the study areas were obtained from soil samples collected from the site and analysed in the laboratory. The effects of these on the rate of soil loss and gullying were determined.Using hydrological, hydraulics and structural analysis along with the acquired data, control measures were proposed for the gully sites. These included the design of drop structures to control the runoff from the gully heads and prevent further under cutting of the heads. The use of Vertiver grass for bank stabilization and catchment areas protection was proposed. The results of the studies and control measures proposed can be adopted for planning for gully remediation and control in other similar situations.