First step to understand the importance of new deep aquifer pumping regime in groundwater system in a developing country, Kwale, Kenya Nuria Ferrer 1,2, Albert Folch 1,2, Willy Sasaka 3, Mike Lane 3, Calvince Wara3, Said Banje 3, Mike Thomas 3, Dan Olago 4, Jacob Katuva 5, Patrick Thomson 5, Emilio Custodio 1 and Rob Hope5, Nuria Ferrer 1,2, Albert Folch 1,2, Willy Sasaka 3, Mike Lane 3, Calvince Wara3, Said Banje 3, Mike Thomas 3, Dan Olago 4, Jacob Katuva 5, Patrick Thomson 5, Emilio Custodio 1 and Rob Hope5, 
1Department of  Civil and Environmental Engineering, Universitat Politècnica de Catalunya (UPC), Jordi Girona 1-3, 08034 Barcelona, Spain., 2Associated Unit: Hydrogeology Group (UPC-CSIC),  3 Rural Focus Ltd., Kenya , 4 Department of  Geology, University of  Nairobi, Kenya, 
5Smith School of  Enterprise and the Environment, Oxford University, UK
1Department of  Civil and Environmental Engineering, Universitat Politècnica de Catalunya (UPC), Jordi Girona 1-3, 08034 Barcelona, Spain., 2Associated Unit: Hydrogeology Group (UPC-CSIC),  3 Rural Focus Ltd., Kenya , 4 Department of  Geology, University of  Nairobi, Kenya, 
5Smith School of  Enterprise and the Environment, Oxford University, UK

## A. Introduction A. Introduction D. Results And Discussion D. Results And Discussion

Global population growth not only causes increased demand for fresh water, but also provokes a decrease in the quality and quantity of this resource. To avoid this deterioration it is essential to undertake careful management of surface water and groundwater (Pimentel et al., 2004).

Groundwater management starts with an accurate hydrogeological characterization of the aquifer system. This is particularly important in aquifer systems with fast-changing abstraction regimes, as is the case for aquifers in many African countries. In this study of Kwale County, Kenya, we characterize the coastal groundwater system made up of an unconfined shallow aquifer and a confined deep aquifer underlying the shallow.

Global population growth not only causes increased demand for fresh water, but also provokes a decrease in the quality and quantity of this resource. To avoid this deterioration it is essential to undertake careful management of surface water and groundwater (Pimentel et al., 2004).

Groundwater management starts with an accurate hydrogeological characterization of the aquifer system. This is particularly important in aquifer systems with fast-changing abstraction regimes, as is the case for aquifers in many African countries. In this study of Kwale County, Kenya, we characterize the coastal groundwater system made up of an unconfined shallow aquifer and a confined deep aquifer underlying the shallow.

This groundwater system has long served urban water demands, local communities and an established tourism industry, but now faces unprecedented This groundwater system has long served urban water demands, local communities and an established tourism industry, but now faces unprecedented ground and surface water resource demands, especially from KISCOL's (5,500 hectares of irrigated sugarcane) and the country's largest mining operation
(Base Titanium Ltd.) which commenced operations in 2013. ground and surface water resource demands, especially from KISCOL's (5,500 hectares of irrigated sugarcane) and the country's largest mining operation
(Base Titanium Ltd.) which commenced operations in 2013. ground and surface water resource demands, especially from KISCOL's (5,500 hectares of irrigated sugarcane) and the country's largest mining operation
(Base Titanium Ltd.) which commenced operations in 2013.

Despite both companies having drilled deep boreholes around the study area (416 km2) to extract groundwater from the deep aquifer, no major pumping activity has started yet, allowing baseline evaluation.

Scattered around the study are 440 handpumps (Thomson et al., 2012) accessing the shallow aquifer to provide drinking water to over 90,000 people.

Despite both companies having drilled deep boreholes around the study area (416 km2) to extract groundwater from the deep aquifer, no major pumping activity has started yet, allowing baseline evaluation.

Scattered around the study are 440 handpumps (Thomson et al., 2012) accessing the shallow aquifer to provide drinking water to over 90,000 people.

Despite both companies having drilled deep boreholes around the study area (416 km2) to extract groundwater from the deep aquifer, no major pumping activity has started yet, allowing baseline evaluation.

Scattered around the study are 440 handpumps (Thomson et al., 2012) accessing the shallow aquifer to provide drinking water to over 90,000 people.

This work is part of the "Gro for Good: Groundwater Risk for Growth and Development" project, one of a number of consortium projects funded through the UPGro Progamme - Unlocking the Potential of Groundwater for the Poor (*http://upgro.org/consortium/gro-for-good/*).

## B. Objectives B. Objectives Total Thermotolerant Faecal (Ttf) Bacteria Pollution:

The main aim is to define the system and to understand the complex interactions between the aquifer units and water users before major pumping starts. In this presentation we show the results obtained from the first field sampling survey (Sept 2015).

The main aim is to define the system and to understand the complex interactions between the aquifer units and water users before major pumping starts. In this presentation we show the results obtained from the first field sampling survey (Sept 2015).

21 of the 25 wells which are polluted by TTF supply drinking water to local communities.

## C. Methodology C. Methodology E. Conclusions E. Conclusions F. Future Research F. Future Research

-This initial field survey and analysis has provided a useful start towards understanding the recharge rate and area for the deep aquifer and characterizing the groundwater quality of both deep and shallow aquifer systems. -Improved knowledge of the deep aquifer system will be very important for sustainable water management in the Kwale area as further demands are placed on this resource. -Isotopic signals suggest that the recharge area of the deep aquifer is located on the west part of the study area, on the Shimba Hills Range, and that the recharge of the aquifer is quite fast. -As so many people depend on the shallow aquifer for their drinking water, monitoring water quality in this aquifer is also important for management. TTF pollution is indicated in many open wells, although the source is not yet defined (see Future research). The wider project will be gathering more evidence relating to the impacts that improved water supplies can have on community health. -The industrial sugar cane plantations do not appear to be a source of nitrate pollution. -This initial field survey and analysis has provided a useful start towards understanding the recharge rate and area for the deep aquifer and characterizing the groundwater quality of both deep and shallow aquifer systems. -Improved knowledge of the deep aquifer system will be very important for sustainable water management in the Kwale area as further demands are placed on this resource. -Isotopic signals suggest that the recharge area of the deep aquifer is located on the west part of the study area, on the Shimba Hills Range, and that the recharge of the aquifer is quite fast. -As so many people depend on the shallow aquifer for their drinking water, monitoring water quality in this aquifer is also important for management. TTF pollution is indicated in many open wells, although the source is not yet defined (see Future research). The wider project will be gathering more evidence relating to the impacts that improved water supplies can have on community health. -The industrial sugar cane plantations do not appear to be a source of nitrate pollution.

## Alkalinity - Digital Tritator By Hach Of The Usa Alkalinity

- Potentiometric titration
The isotopic signal is lighter at higher altitudes such as Shimba Hills Range (west area).

## Hydrochemical Results:

Calcium bicarbonate facies are predominated.

Similar signals are found in the samples from the deep boreholes located on the coastal area.

Most of the wells which present saline intrusion are located on the coastal area, on Pleistocene coral geological materials. There is a clear correlation between stiff diagrams and geological units. The residence time is low.

## G. References G. References

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Study the hydrochemical evolution of the system
comparing dry (March) and wet (June) seasons.
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Study the hydrochemical evolution of the system
comparing dry (March) and wet (June) seasons.
Pimentel D, Berger B, Filiberto D, Newton M, Wolfe B, Karabinakis E, et al. Water resources: Agricultural and environmental issues. BioScience 2004; 54: 909-918. Levin, N.E., Zipser, E.J., Ceding, T.E., 2009. Isotopic composition of  waters from Ethiopia and Kenya: Insights into moisture sources for eastern Africa. J. Geophys. Res. Atmos. 114, 1–
13. Thomson, P
., Hope, R., Foster, T., 2012. GSM-enabled remote monitoring of  rural handpumps: a proof-of-concept study. J. Hydroinformatics 14, 829–839

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Define the connection between aquifer units.
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Define the connection between aquifer units.
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Create a groundwater flow model of the system.
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Create a groundwater flow model of the system.
Acknowledgements: The research is primarily supported under the NERC/ESRC/DFID Unlocking the Potential of Groundwater for the Poor (UPGro) as a Catalyst Grant (NE/L001950/1) with work extending until 2019 as a Consortium Grant (NE/M008894/1), see http://www.upgro.org. Data for the

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Define the sources and mechanisms of chemical
and biological contamination.
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Define the sources and mechanisms of chemical
and biological contamination.