Gauges Needed in West Africa

Larry Awosika
Nigerian Institute for Oceanography and Marine Research
P.M.B. 12729, Victoria Island
Lagos, Nigeria

The following text is an edited version of a GLOSS IOCEA (IOC - East Atlantic) status report presented to IOC by Larry F. Awosika, the IOCEA GLOSS Regional Coordinator at the Bordeaux GLOSS meeting in February 1995. Several years ago Sweden donated four float gauges to the region which were installed with the help of a German expert. However, a number of problems were experienced in keeping them operating. At the present time, four more Swedish float gauges could in principle be installed. The report discusses where they might be sited, and discusses some of the difficulties.

GLOSS in the IOCEA region can best be described as being in its developmental stage. With about 19 coastal countries in the region, only two tide gauges (Lagos in Nigeria and Dakar in Senegal) are known to be fully functional and supplying data to the PSMSL. This is because many of these gauges lack spare parts, maintenance, consumables and trained personnel. Ghana is yet to report on the status of a float tide gauge (Ott type) installed in Tema with the assistance of a German expert, Dr.B.S.Scharringhausen. These two stations in Lagos and Dakar are equipped with the acoustic Next Generation Water Level Measuring System gauges, while the Lagos station also has a working float gauge of the set of four Swedish gauges.

IOC in 1994 recognised the need to improve the GLOSS network in the region. Along this line, it asked the IOCEA GLOSS Coordinator to assist in identifying those countries that would like to receive and install any of a further set of 4 gauges donated by Sweden. The Coordinator sent out a questionnaire to all the GLOSS Contacts in 15 countries in the region. Only four countries (Sierra Leone, Togo, Gambia and Cote d'Ivoire) completed and returned the questionnaire and indicated their willingness to receive the gauges. However, there was a general consensus that national contributions for funds to construct shelters and stilling wells were lacking.

Following this excercise, the following recommendations can be made:

1. An IOC mission should be initiated to Cote d'Ivoire (Abidjan), Togo (Lome), Ghana (Accra and Tema), Benin (Cotonou), Cameroon (Douala), Guinea (Conakry), Sao Tome, and Congo (Pointe Noire) to collect first hand information on the status of the GLOSS stations and the possibilities of either establishing new stations or refurbishing the old ones.

2. There is a need to increase the number of tide gauge stations in the region. Efforts should be made to install the available four gauges in the countries that indicated their readiness to accept them. The NIOMR in Lagos intends to install a gauge in the Escravos estuary in the Niger delta and would be happy to receive one of the gauges. IOC should also look into the possibility of providing funds to the recipients of the gauges for shelters etc. and for installation purposes.

3. Training of regional scientists in the installation, maintenance, collation and analysis of tide data should be resumed. The sea level training at Bidston, UK (which was suspended several years ago because of a lack of IOC funds) was a good programme and should be reinstated.

4. Efforts should be made for the provision of regular maintenance of existing and proposed stations. Regular supply of tidal charts and other consumables should form part of the GLOSS programme in the region.

5. Transfer of data and information on tidal data between scientists in the region should be part of the programme. This could be incorporated in the data exchange network centre in Abidjan.

6. Efforts should be made to increase the participation of regional scientists in global sea level activities.

Summary of Gauges in the Region:


GLOSS Code     Location                      Type        Status

 253           Dakar, Senegal                F/A         Operational
 254           Porto Grande, Cape Verde      ?           ?
 255           Conakry, Guinea               F           Operational
 256           Aberdeen Point, Sierra Leone  -           Not Operational
 257           Abidjan, Cote d'Ivoire        ?           ?
 258           Tema, Ghana                   F           Operational (?)
 259           Lagos, Nigeria                F/A         Operational
 260           Sao Tome                      P           ?
 261           Pointe Noire, Congo           F           ?
 280           Doula, Cameroon               -           -

F = float type; A = acoutic type; P = pressure type