News and Updates
Geophysical Fieldwork in Tanzania and Kenya
Geophysical surveying at the sites in Tanzania and Kenya were undertaken during a 3 week field campaign in mid-April. The QUB geophysical team, together with 200kg of equipment arrived in Dar es Salaam on the 16th April. Together with Simon Melchioly and assistants the first site investigations were undertaken at Kilwa Masoko and Kilwa Kisiwani (island) on the SE coast.
The region was still in the middle of a particularly intense rainy season, which caused some interruptions to the surveys.
Figure 1: Leaving harbour at Kilwa Masoko and arriving at Kilwa Kisiwani on a thundery morning to begin a survey of the island using Electrical Resistivity Tomography (ERT) and Transient Electro-magnetics (TEM). (Left Photo: Rachel and the Antiquities Dept. skipper; Right Photo: L-R Joseph, Jean-Christophe, Saidi and Simon).
Figure 2: The ERT survey passes Kisima Kikuu, an ancient well which still proves a good source of fresh water on the island. A modern hand-pump operated borehole is in the background, currently broken and yielding saline water.
A 700 m ERT profile and several TEM soundings were taken in the north of the island, crossing the area with the largest and oldest well.
On the mainland, in Kilwa Masoko, investigations targeted the area in the centre of the town where 4 boreholes supply most of the town’s water (300m profile) and north of the town a 1.2km ERT profile and TEM measurements extended from the East coast to the airport.
From Kilwa the team returned to Dar es Salaam and onward to Pwani University in Kilifi, Kenya, the base for the Kenyan surveys. Unlike Tanzania, the Kenyan coast was in a period of sustained drought. The expected rains had not arrived so the ground was extremely dry and resistant, which made electrical contacts difficult and meant each electrode had to be watered to improve contact.
Figure 3: Dry conditions in Kilifi, Kenya during surveying.
Two long ERT profiles were taken in the town north of the bridge across the Creek; one parallel to the coast and intersecting the creek and another normal to the coast to the north of the town. Both were approximately 1km in length.
Figure 4: Inspecting an unusable, salty well on a farm close to our survey area in the north of Kilifi town.
With assistance from the team at Pwani University (led by Halimu Shauri), and particularly Rama and Joseph who helped in the field, work went to schedule and was completed without incident. During the course of the survey we had the opportunity to meet a lot of local people, who provided some really useful feedback and information.
Currently the results are being processed and circulated to the project team.
The loan of the TEM from the Department of Geology of Dar es Salaam University, as well as the valuable assistance of Joseph Mutua from the British Institute in Eastern Africa are gratefully acknowledged.
Field campaigns are underway through February and March in all partner countries on the groundwater, environmental and sociological work packages. For groundwater this should provide an overview of conditions at the end of the dry season and a later round of sampling will provide an overview during the impending wet season (mid-May).
On the 16th and 17th January we held our first group meeting at Kenyatta University, Nairobi with representatives from partner institutions at University of the Comoros, Pwani University and Kenyatta University, Kenya; Dar es Salaam University and Sokoine University, Tanzania and Queen’s University Belfast.
Partners at the KU Conference Centre (l-r) Ibrahim Kassim, Rachel Cassidy, Joy Obando, Ibrahim Mohamed, Simon Melchioly, Ibrahimu Mjemah, Halimu Shauri, Jean-Christophe Comte, Beatrice Mwega (missing from photo Mary Makokha)
Simon Melchioly, UDSM, presents an overview of the Kilwa site to participants during the meeting
Partners are working to extend networks and reach out to stakeholder groups in each area to ensure their collaboration with the project.
At the start of the project it was imperative that all instrumentation was quickly installed in each of the field sites in Comoros, Kenya and Tanzania to ensure we get as close to a year of data for each site. An automatic weather station and borehole dataloggers were set up in Kilwa (Tanzania), Kilifi (Kenya) and in Grande Comore at the start of August.
One of the major wells on Grande Comore
Borehole inspection for installation of loggers, Pwani, KE.
Installation of new weather station, Kilwa, TZ
The weather stations provide 15 minute records of rainfall and hourly records of wind speed and direction, solar radiation, relative humidity and temperature while the borehole dataloggers record water level, temperature, conductivity and atmospheric pressure at 15 minute intervals.