Town/City: 

Port Louis

State/Province: 

Port Louis

Country: 

Mauritius

Latitude/Longitude: 

20° 09' S & 57° 30' E

Information supplied by

Daphne Wellman

98wellma@utsc.utoronto.ca

27, Collinsgrove Road, Scarborough, ON, M1E 3S3

Dated Mon Nov 19 10:35:48 2001  

Information Topics:

City Description:

Port Louis is the capital and main port of the small volcanic island of Mauritius. Its administrative and economic center is part of a larger, arched urban area that stretches diagonally across the country from Port Louis to the central plateau (see map). This urban area developed as a result of bursting activity in the early 1980s as the country moved from an agricultural based economy to a more diverse economy.  Port Louis has a population of 132 460 (1990 census) which roughly represents 10% of the country’s total population. Like most modern cities, its metropolitan population is composed of a variety of ethnic groups. This ethnic diversity however, is consequent of its colonial past and can be seen in the population at large as well.  Its claim to fame in the outside world is its high quality port that, prior to the opening of the Suez Canal, was the favoured docking site for large merchant ships travelling trade routes.  It was also home to the infamous dodo bird.

 

 

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Climate:

The island of Mauritius lies in the Indian Ocean some 800 km off the coast of Madagascar. In this part of the world, it is pretty much warm all year round.  During the hot season from November to April, temperatures can reach 35º C whereas in the cold season from May to October, temperatures are about 10º lower.  Although precipitation events occur throughout the year, they are most common during the summer when tropical cyclones bring heavy rain and strong winds.  The spatial distribution of these rainfall events is highly influenced by the south easterly trade winds and by island topography. In the north and northwest portions of the island, it is relatively drier than in the south and southeast because the area is less exposed to the trade winds.  It is also sheltered by mountain belts encircling the central plateau that force air parcels to discharge their water in the south and upon the central plateau before descending upon these areas. Typical average annual rainfall values are as follows: 900 mm on the northwest coast, 4000 mm on the central plateau and 1300 mm on the southeast coast. Port Louis which is situated in the northwest portion of the island has an average annual temperature of 23º C and an average annual rainfall value of 1719 mm.

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Basic Hydrogeology:

The island of Mauritius formed as a result of two major periods of volcanic activity. The first of these began some 10 million years ago as the African and Australo-Indian tectonic plates were diverging.  It was this divergence that was ultimately responsible for the surfacing of basaltic materials and the emergence of the island as one huge shield volcano.  At some point this shield volcano collapsed in upon itself creating a caldera complex that gave rise to the island’s central plateau and three surrounding mountain ranges.  The more recent period of volcanic activity which began some 3.5 million years ago was due to the rising of magma through fractures and fissures of the collapsed caldera complex. This produced a northward moving chain of small volcanoes that poured layers upon layers of lava towards the ocean forming the fertile coastal plain in the north. These layers are much more permeable than the older basaltic layers.  They drain precipitation from the central plateau towards the north.   There are also faults and dykes lined with intrusive rock along the ancient lava flow path that further encourage water drainage towards the north.  The one thing that impedes northward drainage of water in this geologic formation is the presence of clay beds.  There are four other aquifers that have been identified on the island.  All have the central plateau as the common recharge area.  The district of Port Louis and Port Louis itself draws approximately half of its municipal water supply from the reservoirs of these aquifers.  The other half is obtained from surface water supplies.

 

   

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Water Use:

Most of the island’s water resources are used for irrigation purposes (53%).  The rest is used for hydroelectric power generation (27%) and municipal consumption (20%).  The water is issued from one of the 10 reservoirs on the island that get their provisions from ground water reserves and/or surface water supplies. However, inefficiencies within the water distribution system often force the withdrawal of greater amounts of water than is actually required.

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Groundwater Issues:

Increases in island population as well as recent droughts have forced increased water withdrawals from groundwater reservoirs. It has also forced Government officials to seriously reconsider their national policy regarding water usage.  Fear of future water stresses and contamination is prompting action, but also raising conflict between different interest groups.  Finding funding for research and for the purchase of the technology necessary to deal with these emerging problems is also an issue.

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Groundwater Problems:

The main problem the island of Mauritius and its capital city of Port Louis face with respect to groundwater is aquifer pollution.  Roughly 48% of the island’s surface is cultivated.  The application rate of agrochemicals such as chemical fertilizers is estimated to be three times higher than that of Western Europe.  The main agricultural crop that is harvested on this land is sugarcane and not surprisingly another big source of pollution is sugar milling. There are 19 sugar mills on the island and most of them release the liquid waste from the cane crushing process directly into the environment. The second most important source of pollution is industry.  While the main industrial zones are concentrated in the metropolitan area of Port Louis, smaller industrial zones are pretty much scattered all over the island. These smaller industries include leather tanning, galvanising, battery manufacture, dyeing and washing industries. They pose a bigger threat to groundwater pollution because they are built upon the main aquifers of the island. When they release their untreated effluent into the environment, as most of them do, the effluent can infiltrate the groundwater supplies.  In the main industrial zones near Port Louis, effluent is discharged into the sea where it kills the island’s coral reef, but doesn’t get into the groundwater supply. The final big source of pollution is domestic waste water.  The island has four main sewer networks that basically serve the urban population.  The rest of the island, which represents roughly 80% of the total population, has no access to a sewerage system.  They usually end up digging pits in their back yards and dump used water there.  This poses a serious threat in areas where water tables are shallow.

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Solutions:

Faced with the dangers of aquifer contamination and the threat of another drought such as the one they experienced in 1999, Mauritians have begun reforming their current agricultural practices.  Focus is now on water-saving techniques and non-labour intensive techniques. Attempts are being made at replacing inefficient surface irrigation systems with drip or sprinkler systems.  Attempts are also being made at diversifying crops and developing crop combinations that keep water and nutrients within the farming system so that cut backs on irrigation and chemical inputs can occur.  It is clear that water uptake by both the agricultural and industrial sectors needs to be monitored as well as the quantity and quality of their effluent discharge. The Government’s Water Research Unit has undertaken such a project and suggestions for future courses of action will stem from the results of the study.  Meanwhile, the Mauritius Environmental Sewerage and Sanitation Project has been launched to provide sewage treatment facilities and better access to them to the rural population.  All these projects receive partial funding from outside the country.

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References and Other Author(s):

Agence universitaire de la francophonie Centre d'Accès à l'Information de Maurice (Au.) (2001, October 12-last update). Le domaine de l'eau en République de Maurice- Île Maurice et Île Rodrigues: Les actions techniques de la France [Homepage of Centre d’Acces a l’Information de l’Universite de Maurice], [Online]. Available: http://www.mu.refer.org/cop/wru/accueil.htm   [2001, October 14]

Central Electricity Board (Au.) (2001, June 19-last update). Power Plants [Homepage of the Central Electricity Board], [Online]. Available: http://ceb.intnet.mu/Generation/Plants.htm  [2001, October 12]

Central Statistical Office (CSO) (Au.) (2001, April 10-last update). Demographic characteristics of the resident population at the 1990 Census according to boundaries revised in 1991   1992 [Homepage of Ministry of Economic Development, Financial Services and Corporate Affairs], [Online]. Available: http://ncb.intnet.mu/medrc/housing/table2.htm [2001, October 4]

Central Water Authority (Au.) (2001,April 20-last update). Sources of Water [Homepage of the Central Water Authority], [Online]. Available: http://ncb.intnet.mu/putil/cwa/sources.htm  [2001, October 12]

COMPNet USA-MAURITIUS (Au.) (2000-copyright). Capital City & Other major cities [Homepage of Mauritius Island Online], [Online]. Available: http://www.maurinet.com/cities.html [2001, October 4]

Eland Systems Limited (Au.) (2001-copyright). Mauritius [Homepage of Eland Newsroom], [Online]. Available: http://www.elandnews.com/mauritius/weather.html  [2001, October 4]

Facknath, S. and B. Lalljee (Au.) (1999, August-copyright), Soil and Crop Management for Improved Water Use Efficiency in Agriculture under Conditions of Water Stress [Homepage of PROSI Magazine], [Online]. Available: http://www.prosi.net/mag99/367aug/soil367.htm [2001, October 13]

The Hutchinson Family Encyclopedia, Online Edition (Au.) (1999-copyright). Mauritius [Homepage of WHSmith.co.uk], [Online]. Available: http://ebooks.whsmithonline.co.uk/encyclopedia/10/C0000110.htm  [2001, October 11]

Institute For Environmental and Legal Studies (Au.) (2001, August 14-last update). Mauritius and its environment [Homepage of the Institute For Environmental and Legal Studies], [Online]. Available: http://www.intnet.mu/iels/index.htm [2001, October 13]

Jootun, L., M. Bhikajee, R. Prayag and R Soyfoo (Au.) (2001, March 31-last update) Strategic Action Plan for Land-Based Sources and Activities Affecting the Marine, Coastal and Associated Fresh Water Environment in the Eastern African Region [Homepage of  the United Nations Environment Programme Eastern Africa], [Online]. Available: http://www.unep.org/eaf/Docs/SAPEaf5/maurit.htm  [2001, October 13]

Ministry of Public Utilities (Au.) (1999, October 25-last update). Water Resources unit [Homepage of the Ministry of Public Utilities], [Online]. Available: http://ncb.intnet.mu/putil/wateresc/index.htm  [2001, October 13]

Patrice, Raynard  (Au.) (1999, March-last update). Ile Maurice [Homepage of Raynard Patrice], [Online]. Available: http://perso.club-internet.fr/erra/RAYNARD/expose.htm  [2001, Ocotber 12]

Water Resources Unit (Au.) (1997-copyright). Structure schématique de l'Ile Maurice [Homepage of the Water Resources Unit], [Online]. Available: http://www.refer.org/mrice_ct/cop/wru/  [2001, October 12]

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Contacts:

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