The development of models for prediction of gully growth and head advancement A case study: Queen Ede gully erosion site, Benin city, Edo state, Nigeria

This paper examines gully growth and head advancement at the queenede gully site, benin city. this is achieved by observing gully growth and headadvancement between the year 2000 and 2012 using eld surveys, aerial photographs andgeographical information. also, experimental models such as thompson [1], [thompson,j.r. quantitative eect of watershed variables on the rate of gully head advancement,trans asae, 7, pp. 54-55 (1964)]. the american soil conversation service, scs (i) andscs (ii), and fao models, were used for estimating migrating headcuts over a studyperiod. results obtained revealed that the gully width varied from 15.6 m to 99.5 m, whilethe depth varied from 0.5 m to 13.8 m. the volume of soil loss was 372, 775 m3 overan area of 104.4 m2. a mathematical model is proposed for gully growth (ga) and headadvancement (ra), which is hereby presented as:(i) ga = 0:15r0:2679l0:0873a l0:09179w e0:009860p0:06773:(ii) ra = 0:15a0:5328s0:14p0:6778e:the model has been tested against the best existing theories and found to give the sameorder of error.