Guidelines for Coastal Water Quality

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The Ministry of Local Government and Environment has, in consultation with the Ministry of Agriculture, Fisheries and Co-Operatives (Albion Fisheries Research Centre), the ministry of Public Utilities (Water Resources Unit, Central Water Authority and Waste Water Authority) and the Ministry of Health and Quality of Life, formulated the following guidelines for Coastal Water Quality and invites the views and comments of interested parties and the public in general on the guidelines.

Comments should be addresses to the Permanent Secretary (Attn. Mr. P. Ramgolam), Ministry of Local Government and Environment, Ken Lee Tower, 2nd Floor, Barracks Street, Port Louis up to 30 November 1998 at latest.

Date 20 October 1998.

(Note from the Institute: Comments on the guidelines by web surfers can, on request, be transmitted via the Institute to the concerned Ministry, e-mail to, the Institute reserves the right to edit comments beforehand.)

Ministry Of Local Government and Environment

Guidelines for Coastal Water Quality

The following guidelines are intended to inform the public about coastal water quality requirement for various activities as shown below:-

ClassificationPrincipal Beneficial Uses/Objectives
Category A-Conservation

Class A1 - Conservation of Coral Community

Class A2 - Conservation of Natural Areas

A1 - Conservation of Coral Community

A2 - Conservation of natural areas such as mangroves, sea grasses, wildlife habitat and marine spawning, nursing and feeding grounds.

Category B - Recreation

Class B1 - Primary Contact

Class B2 - Secondary Contact

B1 - Water sports like swimming, diving, surfing where there is direct contact.

B2 - Water sports such as boating, fishing and other activities involving less body contact or where direct contact with water may occur but the probability of body immersion is minimal.

Category C - Fisheries

Class C1 - Aqua culture

Class C2 - Shellfish

C1 - Propagation of marine life such as fish. Crabs, shrimps and other marine fauna.

C2 - Culture of Shellfish - oysters, mussels, clams.

Category D_-Industrial

Class D - Industrial

D - Natural water resources used as a receiving water body for industrial and agricultural discharges (harbour, power station and other industrial activities).
Category E_- Environment

Class E - Protection of the Environment

E - Up to the limits of which no unpleasant nuisance is caused to people in their lives including passive recreation

Each activity requires different water quality and this is indicated underneath.

Category A: This category comprises two classes: A1 and A2. Class A1 is intended for the coral ecosystem and requires seawater quality which will not hamper healthy coral growth. Class A2 is for the conservation of natural areas as mentioned in the table above and requires a slightly less stringent water quality.

Category B is intended for recreation purposes. Class B1 defines the water quality needed for sports such as swimming, diving, surfing, etc. where there is maximum body contact with the water. For this class the potential health hazards due to pathogenic micro-organisms have been considered. Class B2 is intended for water sports such as boating, fishing, etc. where there is likely to be minimal body contact with water, and so the quality of the water is less stringent especially with regard to pathogenic micro-organisms.

Category C concerns fisheries. Class C1 is intended for the production of fish, crabs, shrimps, etc. Class C2 is for the culture of shellfish where the requirements for pathogenic organisms are very stringent

Category D comprises the coastal areas, which act as receiving bodies for industrial and agricultural discharges and include the harbour, power generating plants, and other industrial activities.

Category E is the last category, with no limits imposed for suspended solids or pathogenic micro-organisms but there should be no unpleasant odour to people residing nearby.

It is hoped that proper use of theses guidelines would result in the preservation of the quality of coastal waters around the Republic of Mauritius.

Coastal Water Quality Requirements for Various Categories








coral community


Natural Areas


Primary Contact


Secondary contact









pH-7.5-8.5 7.0-8.56.5-8.56.5-8.5 7.0-8.57.0-8.55.0-9.0 5.0-9.0
TemperatureoCambient ambientambientambient ambientambientambient ambient
Suspended solidsmg/l5 5510 1515--- ---
Dissolved Oxygenmg/l>5 >5>5>5 >5>5>2 >2
Chemical Oxygen Demandmg/l 223 3555 8
Total ColiformsCFU/100 ml 100010001000 5000100070* ------


CFU/100 ml <200<200<200 <1000<20014* ------
Nitrate-Nitrogenmg/l0.2 1.0
Phosphatemg/l0.04 0.1
Oil & Greasemg/l

Not Detectable by N-Hexane extraction method

Total Mercurymg/l0.0005