ISSN 2756-326X
Advances in Agriculture and Agricultural Sciences ISSN 2381-3911 Vol. 6 (4), pp. 001-008, April, 2020. © International Scholars Journals
Full Length Research Paper
Rainfall characteristics, runoff rate and traffic flow on gully morphometric parameter growth and soil loss in sand-mined peri-urban, Uyo, Nigeria
O. E. Essien1* and E. G. Okon2
1Department of Agricultural and Food Engineering, University of Uyo, P. O. Box 4309, Uniuyo Post Office, Uyo, Akwa Ibom State, Nigeria.
2Department of Agricultural and Food Engineering, University of Uyo, P. O. Box 1014, Uyo, Akwa Ibom State, Nigeria.
Accepted 14 January, 2020
Abstract
The number of rain days, rainfall amount, intensity and erosivity, runoff rates and traffic count influenced soil losses or degradation of gully morphometric parameters of length, width and depth, and semi-circular ratio (SCR) and contributed significantly (p<0.01) to gully initiation and growth in sand-mined peri-urban. 42 gullies in 42.80 m2 were studied, indicating that gully initiation and development on sand-mined land use in peri- urban was very intense. Rill/gully erosion initiation was more severe from the onset of rains in March to June than from July to August. June experienced high rainfall intensity, the most erosive rain and the highest gully frequency (21%) in the study area. June to August accounted for 57% of all gully frequencies, which correlated significantly (p <0.01) with runoff discharge (r = 0.811) and traffic count (r = 0.811) and their combined increase led to increased frequency or number of gullies developed. Highest monthly gully frequency (52%) occurred at the middle of the slope with 10, 21 and 17% frequencies at upper, lower slopes and valley sections respectively gully erosion grew by the degradation of the individual morphometric parameters of length, width and depth severally. The only 2nd order gully widened to increase gully growth and soil loss while the 1st order gullies lengthened to achieve gully growth and soil loss. For the 2nd order gully with final stage depth/width (D/W) ratio of 2.20, total soil loss was 155.00T per year.
Key words: Uyo, sand-mined, soil loss, semi-circular ratio, gullies.