Thirsty Cities In War


Written By: Giorgio Nembrini

Lamu is not at war, no doubts.

We have decided to include the town of Lamu in this series of papers to document a situation where the taps may run dry and where the inhabitants may have to collect water from the traditional wells, as it was the case when the dune aquifer was not developed and tapped as it is presently. With the development of the town, the demand for water will increase drastically and the dune aquifer may be at danger to become saline or more saline, due to seawater intrusion, enhanced by the possible  over harvesting of the aquifer. Its protection is a constant concern for the authorities.lamu1-216x300

According to an undocumented study the number of traditional wells of Lamu town was estimated to be close to 300, mainly located in private houses with a few wells in public spaces or within the Mosques. In Shela the number of wells was close to 30.

The study has been carried out to document the importance of these wells for the inhabitants of the town of Lamu and of the village of Shela. A total of 277 well have been surveyed in Lamu and in Shela, including 20  wells located in the dunes well field.

Many households were and are still depending on traditional wells to source their daily water, even if the majority of the users were reserving this water for domestic purposes and using water distributed through the network for their drinking needs.

A high resolution satellite image (QUICKBIRD R) has been used to locate the wells, and a number of physical  parameters like total depth, depth of the water, type of protection, number and characteristics of the pump equipping some of the  wells, number of people using the water    were collected during the survey, carried out with the assistance of the Lamu branch of the Kenya Red Cross and the Lamu Water Department.

Some physico-chemical parameters were also measured.  As little was known about the quantities withdrawn from these wells a study has been conducted in order to appreciate the importance of the salt water intrusion along the shores of the town, using conductivity data, recorded between August and October 2005. .

In Lamu, 155 of these wells are equipped with electrical pumps and the quantities of water retrieved from these wells are considered important as they are providing domestic water to about 6500 people.  33 of these wells over the 212 are managed by communities within the town.

Arcview GIS software has been used to analyse the spatial behaviour of the underground water and to produce thematic maps.  It appears that the salt intrusion is negligible and that the salinity of most of the wells is within the WHO recommendations.

However, preliminary data obtained with field instruments on the possible nitrate contamination of the water in these wells, linked to the ways of disposal of human and domestic wastes, show slightly higher values than the recommended ones and a further study should be carried out to confirm these results

Department of water , 1992

DOWNLOAD HERE: Study of the shallow wells of Lamu.pdf

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