<abstract xmlns="http://www.w3.org/1999/xhtml"><p>Ureje Dam, Ado-Ekiti has witnessed drastic reduction in the water storage capacity of its reservoir. It became imperative to determine the possible cause(s) of the reduction in storage capacity. Geophysical investigation involving the vertical electrical sounding technique of the electrical resistivity method was conducted in the upstream part of the dam. Five lithologic units that include the mud/suspended materials, such as sandy clay, clay, weathered/fractured bedrock and fresh bedrock, were delineated. The respective resistivity and thickness range of the units are 2–19 ohm-m; 147–206 ohm-m, 2–38 ohm-m; 47–236 ohm-m and 455–1516 ohm-m and 0.4–1.9 m; 0.5–2.5 m; 1.0–12.2 m; 7.3–16.4 m and ∞. The thickness of suspended materials, resistivity/thickness of weathered layer and the presence of near-surface impervious layer were used as the main indices for the spatial demarcation of the dam axis in terms of vulnerability to loss of impounded water. Using the cumulative response of the indices, the study concluded that the eastern to southeastern parts of the dam axis showed the highest indications of vulnerability to loss of impounded water.</p></abstract>

Ureje Dam, Ado-Ekiti has witnessed drastic reduction in the water storage capacity of its reservoir. It became imperative to determine the possible cause(s) of the reduction in storage capacity. Geophysical investigation involving the vertical electrical sounding technique of the electrical resistivity method was conducted in the upstream part of the dam. Five lithologic units that include the mud/suspended materials, such as sandy clay, clay, weathered/fractured bedrock and fresh bedrock, were delineated. The respective resistivity and thickness range of the units are 2–19 ohm-m; 147–206 ohm-m, 2–38 ohm-m; 47–236 ohm-m and 455–1516 ohm-m and 0.4–1.9 m; 0.5–2.5 m; 1.0–12.2 m; 7.3–16.4 m and ∞. The thickness of suspended materials, resistivity/thickness of weathered layer and the presence of near-surface impervious layer were used as the main indices for the spatial demarcation of the dam axis in terms of vulnerability to loss of impounded water. Using the cumulative response of the indices, the study concluded that the eastern to southeastern parts of the dam axis showed the highest indications of vulnerability to loss of impounded water.

Spatial Resistivity Mapping of Ureje Dam Floor, Southwestern Nigeria

King Fahd University of Petroleum and Minerals

Materials and Geoenvironment

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.

Prostorsko upornostno kartiranje dna jezu Ureje, JZ Nigerija

Ureje Dam, Ado-Ekiti has witnessed drastic reduction in the water storage capacity of its reservoir. It became imperative to determine the possible cause(s) of...

VES LOCATIONS			KEY
1	10	19	p₁ > p₂ > p₃	= A-Type Curve
2	11	20	p₁ 〈 p₂ 〉 p₃	= K-Type Curve
3	12	21	p₁ 〈 p₂ 〉 p₃p₄	= KH-Type Curve
4	13	22	p₁ 〈 p₂ 〉 p₃ < p₄ < p₅	= KHA-Type Curve
5	14	23
6	15	24
7	16	25
8	17
9	18

Spatial Resistivity Mapping of Ureje Dam Floor, Southwestern Nigeria

Article Category: Original scientific paper

Published Online: Jun 15, 2020

Page range: 245 - 255

Received: Jun 22, 2019

Accepted: Dec 18, 2019

DOI: https://doi.org/10.2478/rmzmag-2019-0025

Keywords
Drastic reduction, vulnerability, spatial demarcation, impounded water

© 2019 Fatoba J.O. et al., published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Colour Chart of the Distribution of the Depth Sounding Curves.

Spatial Resistivity Mapping of Ureje Dam Floor, Southwestern Nigeria

Article Category: Original scientific paper

Published Online: Jun 15, 2020

Page range: 245 - 255

Received: Jun 22, 2019

Accepted: Dec 18, 2019

DOI: https://doi.org/10.2478/rmzmag-2019-0025

KeywordsDrastic reduction, vulnerability, spatial demarcation, impounded water

© 2019 Fatoba J.O. et al., published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Colour Chart of the Distribution of the Depth Sounding Curves.

Keywords
Drastic reduction, vulnerability, spatial demarcation, impounded water