South Poclflc Regionol Environmenl proglomme SPREF Report qnd Studies Series no. l0l Environmenlol lmpqct Assessmenl (ElA) Report on the Augmenlolion Phose of the Afulilo Hydro Power Scheme in Somoo SPREP Llb,rary Geta,loguing',h'Publitationr E*a Onorib, Kome-ri EnriionBeatal .hg*t assesstIent repo,rt : augmentalion phase of Afulilo Hirato Poier $cheme, Sanroa / prepared by Komeri Onsrio and BaIe Tanwr. - *.tpia $arnoa: SPBEP, 1997. ix, 38 p; i fiiaptr tebles ; 29 cloo.. - (SX'REP Reports and Studies ; no.10l)' XSBNi 98244417+7 1. Environrnentd inpact andysis'Samqa 2. Envhounental monitorio.g' Sanoa J, Envirolpentd proteetio-tr - Samoa I. T"rna$a Bde. tr,$ories. ilL S-ourh Facif,rc F"egional Envlronmcnt Frogramno. 33t.V\09614 Publishcd in Noveinbrr 1997 by rhe South Paeifrc Regiatel Environnent Progranr e pOBox2,t0 Apia S*noa Typeset n lt/ L3 Garanond Prfued on recycled paper 90gpn Savannah N[at An (e0%) by QualityPrint L-td Suvan Fiii Covor photogteph shon'ing the Afulils r.€servoir bv Korneri Onorio @ Sor$h Picifie RegiondEnvirornrent Prsgremme' 1995. The South Pacific Regional Environment Programme euthorises the rep-roduo-ion of th;is naterid" wholc o-r il p.Ert, in any fbrm provide-d appropriate acknowledgemert is givm. O riginil Textr F:ngtrieh The views orpmsed in this rqrort are nol neecwarily thosc of the publishcr. South Poeific Reglonol Environment prcgr,omme Environnrentail Imp.act Assessment Report Augmentation Phas€ of .dfulilo Hydro Power Scheme, Samoa Prepared bXr Konred Onorio and BaIe Tamata for the G.overnnrent of $amoa Fubltohed by fiourh Pacifio RegiorialEnrrimnrtrenteOgrirtune A.piri, $anoa Novenrber l99? Contents Acknowledgements vi Executive surnmary vii The Proposal vii Main Impacts vii Conclusion viii Glossary ix 1 Introduction 1 1.1 The Project 1 1.2 EIA Brief I 1.3 Background 2 L.4 Review of Recommendadons of the 1991 EIA Report 3 1.4.1 The Vaipn Scheme 3 1.4.2 Ftotic species 4 1.4.3 Th'elefaga opuarton 4 1.4.4 Social impacts 5 2 The Afulilo augmentation proiect 6 2.1 Raising the Afulilo Dam 6 2.2 Installation of third turbine at Ta'elefaga Power Station 6 2.3 Diversion of zurface water into the Afulilo Reservoir 7 2.4 Installadon of new 4M\f diesel generator at the Tanugamanono Power station 7 3 Existing environment 11 3.1 The Afulilo Reservoir 11 'Vatr 3.1.1 quality in the resemtoir 11 3.2 Ta'elefaga Power Station 12 3,2,1 Noise emission 12 3.3 Ta'elefaga creek 13 3.4 Fagaloa Bay 14 .Vdter 3.4.1 qudlity 14 3.4.2 Social cond:itions 14 3.5 Diesel Generation at Tanugamanono Power Station 15 3.5.1 The diael pmtt station I5 3.5.2 Fuel storage and fire risk 15 3.53 Cooling system 16 3.5.4 Vaste oil and fubaust fumes 16 3.5.5 Noise emission 16 4 Environmental effects of the augmentation prciect 1g 4.1 Increasing Afulilo reservoir volume 18 4.1.1 l-and tenure Ig 4.1.2 Flora and Fauna Ig 4.2 Effea of the East Diversion Canal Lg 4.1.3 Consnuction phase Ig 4.1.4 Forest Clearance 19 4.2.1 Construction 19 4.2.2 Social effeat 20 4.2.3 Flora and. Fauna 20 4.3 lncreased freshwater ourflow into Fagaloa Bay Zt 4.3.1 Thilrace oatfall to stredm 21 43.2 Dischdrge to sed 21 4.4 Additional noise ar Taelefaga Power Station 22 4.5 Instdlation of additional Diesel Generaror ar Tanugamanono Power Station 22 5 Conclusions and recommendations 24 6 References 26 Annexes Annei( 1: Questionnaire for Ta'elefage Villagen 2g Anno< 2: Physiochemical Water quality measuremenrs 30 List of Figures Figure 1: Afulio Reservoir 317.5 merres above sea level g ^t Figure 2: Afulio Reservoir et3I9.Z merres above sea level g Figure 3: Eastern Diversion Canal 10 Figure 4: Sound intensities t7 Figure 5: Noise reduction outside power srarion building 23 List of Thbles Table 1: Afulilo Reservoir'Water Qualiry Measuremenrs 12 power Table 2: Average Noise Measuremenrs ar Ta'elefaga station 13 Table 3: List of fishes now absent from Fagaloa Bay 74 Table 4: Average Noise Measurements at TanuBamanono Diesel Power Plant 17 vt ACKNOWLEDGEMENTS \[e acknowledge the vduable assistance and conributions provided by various people to enable the completion of this environmental impact assessrnent report. rtr0'e are grateful to Michael Nadonn Chief Engineer for the Electric Power Corporation of Samoa, who provided helpful advice on technical aspects of the project and facilitated our field visits to the project site. Thanks are also extended to A.B. Rathod, the Manager Generation at Tanugamanono for the advice on diesel generation and providing a guided tour of the power station. Special thanks are extended to Ms Jaya Balram and the staff of the Institute of Applied Sciences of the Universiry of the South Pacific in Suva, Fiji and at Alafua Campus in Samoa, for the analysis of the water samples and providing water quality measurements. \fle would like to thank the people of Ta'elefaga village for agreeing to meet with the assessors and for helpful discussion. Special thanks to Petelo Ioane who conducted the traditiond village meeting on our behalf with the village matais, and whs had also helped on all field studies. FinallS we acknowledge the assistance of Bismarck Crawley and Petelo Ioane of the Pacific Environment and Natural Resources Information Centre (PENRIC) for providing digital data and the maps for this report and Fatu Tauafiafi for the editing and layout. otl EXECUTIVE SUMMARY The Proposal construction of an eastern diversion The Afulilo Hydro Power Augmentarion channel, behind Alafou village, !o talrc Project was designed specifically to assist advantage of additional zurface nrn-off with the Upolu power sysrem stability. water in the localiry which will be Demand for energy has been growing in channeled under gravity, into the reserwoir. line with grcwth in maximum demand The augmentation project dso include rhe and, while the Afulilo scheme is producing installation of a new diesel generaror ar more energy than anticipated, the sus- Tanugamanono station to assist with the tainable enery outflow of the present Upolu system stabiliry. scheme is limited by warer inflows, reservoir storage volume and insralled Main lmpacts geneftrtion capacity. Because the Afulilo All major componenrs of this project have scheme is rhe only hydro scheme in Samoa significant social impacts. The Alafou with carry over storage, augmentation of community will lose approximately 32 the Afulilo scheme is panicularly percent of its normal zurface water important to increase dry season capaclry drainage. This proposed canal will prove to reduce the amounr of installed diesel drastic to Alafou villagen whose main capaciry ro reduce overall fuel consump problem in the area is shortage of water tion and to lessen th" dry season peak in supply. Fagaloa Bay, on rhe orher hand, fuel consumption. which receives the tailrace waters or rhe outflow fiom the trubine engines, have The Electric Power Corporation (EPC) of seen some fish species disappearing, Samoa, having prepared and submined the especially shellfish. Continued imrndadon Afulilo augmentarion project funding of beaches and reef flat and pools with silt proposal for co-financing by the Asian particles and continued influx of freshwater Developmenr BanI< and rhe European into the sea may have caused rhe lnvestment Bank, have requested (through disappearance of these fish species the Samoan Ministry of Foreign Affairs) (identified in the text of the report) but it is the South Pacific Regional Environment possible that because of the new flow Programme (SPREP) for assistance with regime into the ba5 marine life gromh the environmental impact assessment of the rnay have changed also and or adapted to proposed project. SPREP w.as able ro the new environment. accommodate this request by utilising its own in-house capability and hiring a The raising of the dam height by 1.7 merres technical consuhanr from the Univenitv of will increase the surface area of the Afulilo the South Pacific in Fiji, to under.take water basin that will be inundarcd by warer a qualiry studies and record noise measure- funher 19.4 hectares to a rotal maximum ments. area of.270.4 hectares. It is considered thar minimal impacts will be caused by the The proposed augmentation project will increase in the surface area ofthe reservoir see insrdlation of the third turbine engine as most places dong rhe fringes of the basin at the Ta'elefaga sration, the raising of the have high bank walls but rhere are some A{rrlilo dam to increase wat€r srorage low lying areas. The additional vegerarion capacity of Afulilo reservoir and the that will be under water is rherefore also Augmentation Project of the Afulilo Hydro Power Scheme aiii mininmal. But, because there is additional effects on the marine communities, but vegetation that will contribuk to the these are difficult to predict in advance. rotting vegetation at the botom of the There are already changes within Fagaloa reservoir, the smell and coloration of the Bay due to the Afirlilo project, according to Afulilo water will continue for manv more Ta'elefaga villagers, but again it is difficult years to come. to ascertain that the cause is entirely the rezult from the tailrace waters. It is The installation of a new diesel genemtor at therefore, recommended that an the Tanugamanono power station will not environmental audit of Fagaloa Bay be have significant impacts on the aleady undertaken prior to the commencement of unacceptable environmental condition of the augmentation project to provide the diesel power generation.