Editing Hydrogeology of Kenya

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[https://www.bgs.ac.uk/africagroundwateratlas/downloadGIS.html '''Download a GIS shapefile of the Kenya geology and hydrogeology map'''].
 
[https://www.bgs.ac.uk/africagroundwateratlas/downloadGIS.html '''Download a GIS shapefile of the Kenya geology and hydrogeology map'''].
  
[[File: Kenya_Hydrogeology3.png | center | thumb | 500px | Map of hydrogeology (aquifer type and productivity) of Kenya at 1:5 million scale. For more information on how the map was developed see the [[Africa Groundwater Atlas Hydrogeology Maps | Hydrogeology map]] resource page. [https://www.bgs.ac.uk/africagroundwateratlas/downloadGIS.html Download a GIS shapefile of the Kenya geology and hydrogeology map].]].
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[[File: Kenya_Hydrogeology3.png | center | thumb | 400px | Map of hydrogeology (aquifer type and productivity) of Kenya at 1:5 million scale. For more information on how the map was developed see the [[Africa Groundwater Atlas Hydrogeology Maps | Hydrogeology map]] resource page. [https://www.bgs.ac.uk/africagroundwateratlas/downloadGIS.html '''Download a GIS shapefile of the Kenya geology and hydrogeology map'''].]].
  
  
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||High-yield aquifer systems with good quality water
 
||High-yield aquifer systems with good quality water
  
||Daua and Elgon volcanic rock aquifers
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||Daua and Elgon volcanics
 
|-
 
|-
 
|Minor aquifer
 
|Minor aquifer
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||Moderate-yield aquifer systems with variable water quality.
 
||Moderate-yield aquifer systems with variable water quality.
  
||Mandera - Jurassic (Mesozoic-Palaeozoic)
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||Mandera Jurassics
 
|-
 
|-
 
|Poor aquifer
 
|Poor aquifer
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====Sedimentary - Unconsolidated and Semiconsolidated; Intergranular Flow: Moderate to High Productivity Aquifer====
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====Sedimentary - Unconsolidated and Semiconsolidated; Intergranular Flow====
  
 
{| class = "wikitable"
 
{| class = "wikitable"
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====Igneous Volcanic: Moderate Productivity Aquifer====
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====Igneous Volcanic ====
  
 
{| class = "wikitable"
 
{| class = "wikitable"
  
|Named Aquifers||General Description||Water quantity issues||Water quality issues
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|Named Aquifers||General Description||Water quantity issues||Water quality issues||Recharge
  
 
|-
 
|-
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||
 
||Groundwater typically has low total dissolved solids and high bicarbonate. The volcanic deposits of the East African Rift System are rich in fluoride which leads to high groundwater fluoride concentrations.  For example, concentrations over 10 mg/L were found in the Nairobi area (Coetsiers et al. 2008).
 
||Groundwater typically has low total dissolved solids and high bicarbonate. The volcanic deposits of the East African Rift System are rich in fluoride which leads to high groundwater fluoride concentrations.  For example, concentrations over 10 mg/L were found in the Nairobi area (Coetsiers et al. 2008).
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||
 
|-
 
|-
  
 
|Nairobi Aquifer
 
|Nairobi Aquifer
  
||The Nairobi aquifer is one of the most significant in Kenya. It comprises Plio-Pleistocene volcanics interbedded with old land surface and intervolcanic sediments, and underlies much of the Nairobi metropolitan area. It is a complex multilayered aquifer system, recharged along the eastern edge of the Rift Valley with groundwater moving toward the east. It is unconfined in the recharge zone, becoming confined towards the east. The main aquifer layer, the Upper Athi Series, is confined and typically found at depths of 120 to 300 m bgl. Transmissivity values range from 0.1 to 160 m²/d, with hydraulic conductivities ranging from 0.01 to 1.3 m/d. Storage coefficient values range from 1.2 x 10<sup>-4</sup> to 4.2 x 10<sup>-1</sup> (Mumma et al. 2011). Boreholes are typically drilled to 250 to 400 m depth.
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||The Nairobi aquifer is one of the most significant in Kenya. It comprises Plio-Pleistocene volcanics interbedded with old land surface and intervolcanic sediments, and underlies much of the Nairobi metropolitan area. It is a complex multilayered aquifer system, recharged along the eastern edge of the Rift Valley with groundwater moving toward the east. It is unconfined in the recharge zone, becoming confined towards the east. The main aquifer layer, the Upper Athi Series, is confined and typically found at depths of 120 to 300 m bgl. Transmissivity values range from 0.1 to 160 m²/d, with hydraulic conductivities ranging from 0.01 to 1.3 m/d. Storage coefficient values range from 1.2 x 10-4 to 4.2 x 10-1 (Mumma et al. 2011). Boreholes are typically drilled to 250 - 400 m depth.
 
||Overabstraction causing lowered water levels.
 
||Overabstraction causing lowered water levels.
 
||Often shows naturally high fluoride.
 
||Often shows naturally high fluoride.
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A key reference for these aquifers is Coetsiers et al. (2008).   
 
A key reference for these aquifers is Coetsiers et al. (2008).   
 
====Sedimentary: Mixed Intergranular & Fracture Flow: Moderate Productivity Aquifer====
 
 
{| class = "wikitable"
 
 
|Named Aquifers||General Description
 
 
|-
 
|
 
||Little information on these aquifers is known.
 
|}
 
  
  
====Basement: Low to Moderate Productivity Aquifer====
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====Basement====
  
 
{| class = "wikitable"
 
{| class = "wikitable"
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Prior to the Water Act 2016, the Water Act of 2002 created the mechanisms for planning, including the establishment of the Water Resources Management Authority (WRMA), which had responsibility for regulating the ownership and control of water and making provision for the conservation of surface and groundwater and the supply of services in relation to water and sewerage (Mumma et al. 2011). In 2006, WRMA proposed a policy for the protection of groundwater (Mumma et al. 2011).  
 
Prior to the Water Act 2016, the Water Act of 2002 created the mechanisms for planning, including the establishment of the Water Resources Management Authority (WRMA), which had responsibility for regulating the ownership and control of water and making provision for the conservation of surface and groundwater and the supply of services in relation to water and sewerage (Mumma et al. 2011). In 2006, WRMA proposed a policy for the protection of groundwater (Mumma et al. 2011).  
  
The [http://www.water.go.ke/ Ministry of Water & Sanitation and Irrigation] (formerly Ministry of Water and Irrigation; also known as Ministry of Water and Sanitation) is responsible for the development of water resource legislation, policy formulation, sector coordination and guidance, and monitoring and evaluation.
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The [http://www.water.go.ke/ Ministry of Water and Irrigation (MoWI)] is responsible for the development of water resource legislation, policy formulation, sector coordination and guidance, and monitoring and evaluation.
  
 
=== Groundwater monitoring===
 
=== Groundwater monitoring===
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For further information about transboundary aquifers, please see the [[Transboundary aquifers | Transboundary aquifers resources page]]
 
For further information about transboundary aquifers, please see the [[Transboundary aquifers | Transboundary aquifers resources page]]
 
==Groundwater Projects==
 
 
Information on particular groundwater projects in Kenya, including links to project results and outputs, can be found on the [[Kenya Groundwater Projects | Kenya groundwater projects]] page.
 
  
 
==References ==
 
==References ==

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