The physico-chemical parameters and benthic macroinvertebrates of Ikere Gorge Reservoir were
studied to assess the impact of anthropogenic activities on this man-made lake by collecting surface water and benthic
samples. Physico-chemical parameters were within the allowable limits of USEPA for fresh water bodies apart from
conductivity (0.055 ± 0.002μS/cm) which was below standard. There were significant differences (p<0.05) in the mean
values of DO, BOD, TDS, transparency, nitrate and sulphate between the sampling stations. A total of six genera
(
Chironomus
,
Melanoides
,
Cloeon
,
Bulinus
,
Bellamya
and
Hirudo
) of benthic macro-invertebrates belonging to six
orders (Diptera, Pelecypoda, Ephemeroptera, Heterobranchia, Caenogastropoa and Hirudinida) were recorded in the
reservoir during the study. Pollution tolerant species including
Melanoides tuberculata
and
Chironomus sp. dominated
the benthic macroinvertebrates with a total number and percentage abundance of 674(56.88%) and 435(36.71%),
respectively. Ikere Gorge Reservoir is relatively under stress due to dominance of indicators of pollution.
