Multifunctional Historical Data
for Improved Management
of Reservoirs
Joseph Sang and Caroline Maina
Abstract
Sedimentation surveys play a critical role in
the management of reservoirs. They not only
give information on current volumes but also
records of past sedimentation status. Determining the sedimentation status of reservoirs
provides a means of generating multifunctional historical datasets on sedimentation
rates, thus explaining the nexus of water, soil
and food and its impacts on water quantity and
quality in reservoirs over time. Historical
sedimentation rates, as demonstrated from
assessments carried out in two reservoirs in
Kenya, can inform management of reservoirs
and watersheds where food production is
carried out. This could be critical in
Sub-Saharan Africa (SSA) where up to 58%
of reservoirs are not monitored. A study in
Ruiru Reservoir and Lake Sonachi in Kenya
demonstrates how critical and missing information about the reservoirs and watersheds
could be generated from sedimentation assessment. In the Ruiru Reservoir, which is one of
the critical sources of water to Nairobi,
information such as current volume and
sedimentation rates were obtained. The assessment showed that the reservoir has lost 14%
of its original volume at an average sediment
accumulation rate of 1.75 cm/year. This information is key to the management of the
reservoir and the upstream watershed.
Keywords
Reservoirs Á Sedimentation Á Bathymetric
survey Á Bathymetric survey system
1 Introduction
To tame the problems of water availability man
has always resorted to building storage reservoirs. Reservoirs are used to control the unbalanced spatial and temporal distribution of water.
In water scarce areas, reservoirs store water for
the dry periods, whereas in flood prone areas
reservoirs reduce peak flows and thus protect the
downstream community from floods hazards.
Worldwide over 40,000 large reservoirs (Tiğrek
et al. 2009; Tigrek and Aras 2012) were constructed in the 20th century with a combined
capacity of 6,000 km
3 (Kondolf et al. 2014).
Approximately 2% of these large reservoirs are
in Sub-Saharan Africa (SSA) and have a
J. Sang (&)
Department of Soil Water and Environmental
Engineering (SWEE), Jomo Kenyatta University of
Agriculture and Technology (JKUAT), Juja, Kenya
e-mail: j.sang@jkuat.ac.ke
C. Maina
Agricultural Engineering Department, Egerton
University, Njoro, Kenya
e-mail: caroline.maina@egerton.ac.ke
© Springer Nature Switzerland AG 2021
S. Hülsmann and M. Jampani (eds.), A Nexus Approach for Sustainable Development,
https://doi.org/10.1007/978-3-030-57530-4_6
81
for Improved Management
of Reservoirs
Joseph Sang and Caroline Maina
Abstract
Sedimentation surveys play a critical role in
the management of reservoirs. They not only
give information on current volumes but also
records of past sedimentation status. Determining the sedimentation status of reservoirs
provides a means of generating multifunctional historical datasets on sedimentation
rates, thus explaining the nexus of water, soil
and food and its impacts on water quantity and
quality in reservoirs over time. Historical
sedimentation rates, as demonstrated from
assessments carried out in two reservoirs in
Kenya, can inform management of reservoirs
and watersheds where food production is
carried out. This could be critical in
Sub-Saharan Africa (SSA) where up to 58%
of reservoirs are not monitored. A study in
Ruiru Reservoir and Lake Sonachi in Kenya
demonstrates how critical and missing information about the reservoirs and watersheds
could be generated from sedimentation assessment. In the Ruiru Reservoir, which is one of
the critical sources of water to Nairobi,
information such as current volume and
sedimentation rates were obtained. The assessment showed that the reservoir has lost 14%
of its original volume at an average sediment
accumulation rate of 1.75 cm/year. This information is key to the management of the
reservoir and the upstream watershed.
Keywords
Reservoirs Á Sedimentation Á Bathymetric
survey Á Bathymetric survey system
1 Introduction
To tame the problems of water availability man
has always resorted to building storage reservoirs. Reservoirs are used to control the unbalanced spatial and temporal distribution of water.
In water scarce areas, reservoirs store water for
the dry periods, whereas in flood prone areas
reservoirs reduce peak flows and thus protect the
downstream community from floods hazards.
Worldwide over 40,000 large reservoirs (Tiğrek
et al. 2009; Tigrek and Aras 2012) were constructed in the 20th century with a combined
capacity of 6,000 km
3 (Kondolf et al. 2014).
Approximately 2% of these large reservoirs are
in Sub-Saharan Africa (SSA) and have a
J. Sang (&)
Department of Soil Water and Environmental
Engineering (SWEE), Jomo Kenyatta University of
Agriculture and Technology (JKUAT), Juja, Kenya
e-mail: j.sang@jkuat.ac.ke
C. Maina
Agricultural Engineering Department, Egerton
University, Njoro, Kenya
e-mail: caroline.maina@egerton.ac.ke
© Springer Nature Switzerland AG 2021
S. Hülsmann and M. Jampani (eds.), A Nexus Approach for Sustainable Development,
https://doi.org/10.1007/978-3-030-57530-4_6
81