Investigation into the Causes of Gully Erosion in Parts of Anambra State

Abstract

Gully erosion is a natural disaster that have affected many parts of southeastern Nigeria particularly the state of Anambra. The causes of
progressive gullies in some parts of Aguata local government area of
Anambra state was investigated. The gullies can be found in Ula region
of Ekwulobia, Otaalu region of Akpo, Ogbei region of Nkpologwu and
Achina town. Some samples were collected from the walls of the gully
at depths ranging from 1.5 to 2.5m. Laboratory analysis which include
index property tests and compaction tests were carried out on the
samples. Questionnaire survey and analysis was also carried out to
sample people’s opinion. Unified soil classification system classified all
the soil samples under clayey sands (SC) which is susceptible to erosion.
The empirical values of erodibility factor, K determined show that the
soil samples are moderately erodible. Based on the laboratory test results
and questionnaire responses, it is evident that soil properties and human
activities contribute to the development of gullies. It is recommended
that all effort should be made to protect soils from exposure to runoff
especially at slopes.