REPUBLIC OF MAURITIUS E 20 & MINISTRY FOR PUBLIC INFRASTRUCTURE Waste Water Authoritv Public Disclosure Authorized Montagne Jacquot Environmental Sewerage and Sanitation Project Environmental Impact Assessment Report August 1997 Public Disclosure Authorized -_ --- __ _* Public Disclosure Authorized = 5~~~~. '-I ~ Public Disclosure Authorized BLACK & VEATCH INTERNATIONAL Servansingh Jadav and Partners a AkoniagqneJacquot Sewernage and Snittir on Project Environmeital ImpnpactAs4essment REPORT AUTHORISATION SHEET Client: V/ Waste Water Authority Ministrv for Public Infrastructure Project: Montagne Jacquot Environmental Sewerage and Sanitation Project: Environmental Impact Assessment Report PREPARED BY BLACK & VEATCH INTERNATIONAL ENVIRONMENTAL CONSULTANCY UNIT Dr. E.A.S. Linlev: Principal Environmental Scientist Dr. S.A.Harris: Environmental Scientist Dr. B. Jerni-an: Environmental Engineer. Project Manager Date: August 1997 Cover:lop lefti- proposed site fr- new WWTplant at Mlontagne Jacquot.- hottom lefi - marine life ct the proposed outzi/al site at Moniagne Jaccluot: right - present state of the beach at Fort l ictoria 117arks (May 1997j BlcA & IVeatchinternational a I . 1 .Ilowalgne Jicylaoi Sewerage anuiSanitation Project EnvironmentIalIntpalt .Assessaten: EXECUTIVE SUMMARY 1.0. Introduction The Government of Mauritius commissioned the Sewerage Master Plan stud! in 1992. and one of the key recommendations was that the present sewage disposal arrangements for the Port Louis South and Lower Beau Bassin / Coromandel areas should be improved by constructing a waste water treatment plant at Montagne Jacquot. By implementing the Monta-ne Jacquot project. public health and sanitation. the terrestrial and marine environment around Port Louis would be improved and protected: and the project would help to restore sustainable development of economic activities in tile area aftected by the current sewage disposal arrangements. The project also aimed to minimise industrial pollution by recommending pre-treatment options ftor industrial effluents destined for the new waste water treatment plant. Additional studies carried out in 1994 and 1996 suggested a preliminar' design 'forthe Montagne Jacquot plant based on disposal of treated effluent through an ocean1outfall. and re-use of treated effluent for irrigation of west coast agricultural land. Subsequently. the Waste Water Authority commissioned three studies. The first was to design the various components of the Montagne Jacquot Sewerage and Sanitation project consisting of pumping stations. transmission mains pipelines and an ocean outfall. and to carry out an environmental impact assessment (EIA). The second was to evaluate the technical and economic feasibility of re-use of treated effluent for irri-ation: and the third. to review the institutional and financial arrangements necessar% ftor implementing the sewerage master plan for Mauritius. The present document reports the results of the EIA carried out bv Black and Veatch Interniational. Environmental Consultancy Unit. and should be read in conjunction with the Montagne Jacquot planning and preliminary design reports, and the reports on the economic feasibility of waste water re-use for irrigation as well as the institutional studies. BlacA& I eatclhInternational 11 Mlontagne Jclcqulot SeweragLeatd Su,,itatioil Project Entvironmenttal Impact Assesssment 2.0. Brief description of the Montagne Jacquot project .\ nex\ waste xvater treatmiientplant will be constructed at Montagne Jacquot to treat domestic. commercial and industrial waste water from the Port Louis South. Lower Beau Bassin and Coromandel areas. which together include the main industrial areas and residential areas in southwestern Port Louis. The project includes ne%Npumping stations at Fort Victoria and at Pointe aux Sables to replace the existing works and ocean outfalls. risinul mains to deliver the waste water to the Montagne .lacquot treatment plant. as well as a new outfall at Montagne Jacquot for disposal of treated effluent to the ocean. 3.0. Policy, legal and administrative framewvork. The Environmental Protection Act (1991) of Mauritius provides the legal framework for implementing the National Environmental Policy. which aims to foster harmonN between qualitv of life. environmental protection and sustainable development for present and future generations of Mauritians. In order to comply with the EPA. all major developments and infrastructure projects now require an Environmental Impact Assessment. The present EIA therefore follows the guidelines issued from the MEQOL for carrvin- out and reporting an EIA. Additional guidelines which apply to coastal developments have also been incorporated into the EIA study. As the Montagne Jacquot project will be jointly funded by the World Bank. the Oxverseas Economi:c Cooperation Fund (OECF) and the Government of Nlauritius. the environmental impact assessment requirements of all three were incorporated into the EIA programme for the Montagne Jacquot project. The common features ol all three seis of guidelines provide for: 0 a description of the project components and the environment potentially affected b\ the proposed project. 0 idenitification of significant positive and negative environmental impacts of the project and assessment of their significance. BlacA& IVeiatch Inte'rnatiinal iii WlIon,agIneJacqtuo Sewerage aindSanifiatio,i Proicct EnvironmenralImpact 4 s essnent O an analysis of alternatives for the project. 0 identification ofn measures to mitigate environmental impacts and proposal for a mitigation plan. C an environmenitalmonitoring plan. In addition. the World Bank and OECF echo the provisions of the National Environmental Policy of Mauritius in highlighting the need to address particular issues in the EIA. These include biodiversitv protection. coastal and marine resources management. industrial hazards. land settlement and cultural issues. The 'orld Banlik also requires recommendations for environmental management and training to be included in the EIA. Consequently. this EIA report includes all these requiremiienits.to produce a coherent evaluation of the Montagne Jacquot project suitable for decision making bv all the relevant funding organisations. 4.0. The environment affected by the project T'he environment affected by the project consists of the drainage area to be serviced by the waste water collection svstem. It consists of approximately the southern halt' of the Port Louis Sewerage System. which includes the built up areas of Port Louis South. Cassis. Belle Village and the Plaine Lauzun Industrial Zone: and the lower Beau Bassin reuion includingwthe Coromandel and La Tour Koenig Industrial Estates. the Pointe aux Sables communitv and residential areas to the south. The affected area includes sections of four of the countrv's nine administrative districts, namely the Black River. Plaines Wilhems. Moka and Port Louis. The coastal waters likely to be affected by the new discharge from the ocean outfall. stretch from the Pointe aux Sables reef to south of Montagne Jacquot. in an area some X)( m to I km ottshore. The area currently affected bv the existing discharge arrangements stretches from Port Louis to the southern end of the Pointe aux Sables reef. with impacts visibly apparent along the shoreline. in shallow lagoon waters and on the sea floor. Black-& £'enichInter,nationul iv 2lI4ntagne Jac leor Sewerage o'ad Saittation Project E,,vironrneltal imptactAssesSnment 5.0). Principal significant impacts associated with the project Impacts of the project were evaluated according to their magnitude. duration and extent. and those w hich were found to produce highl' significant impacts were further revxiewed.to determine whether thev were reversible. irreversible or cumnulative.the likelihood of'their occurrence and potential risks also associated with their effects. It was concluded that the overall effects of the Montagne Jacquot project wvillbe overwvhelminglypositive, since it will result in major improvements in quality of life and environmental quality in the areas affected bv the present discharge arrangements. In turni these improvements are likely to result in a reduction in public health hazards. and revitalised ecoInomy1Nin the tourisin. property. real estate. and services sectors in the currenitlv affected area. The improvements in coastal water quality will also assist in the rehabilitationi of coastal ecosvstems in the long term. From the results of the environmental impact analysis it was evident that the principal silnificant negative impacts of the project on the community would occur during the construction phase. during laying of the main transmission pipeline if the land-based option was adopted. when congestion of traffic, noise. dust and general disruption will cause considerable irrconvenience. In addition. even although the effluent will meet anticipated standards for water quality. there will be longer term impacts on water quality and benthic communities off Montagne Jacquot in the effluent discharge area which will be significant. but limited in extent to the immediate discharge area. The outfall location off Montagne Jacquot is one of the few breaks in the barrier reef encirclinueMauritius where minimal damage to reefs and lagoon waters from an effluent discharue would be experienced. The potentiallv affected benthic and planktonic communities at the site were evaluated and no conservation-worthy species or unique habitats which could be a particular concern were found.