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. Currently noise current envincnmentd status, and thus pollution and exhaust fumes are causing record baseline &ta, of the bay to better major concerns with the nearby dercrmine the likely impacts of the project. households. Waste water and oil pollution The Fisheries Division together with the from the powerstation have also caused Department of Environment and concerns for the villagers down the valley Conservation could undertake this task and and downstream of the powerstation. also design a follow up post commissioning monitoring programme. The fisheries and Conclusion marine study at Fagaloa Bay should take The augmentation project is a particularly prioriry over the proposed government's important phase of the Afulilo hydro fish stocking of Afulilo reservoir with power project to imprcve the efficiency of exotic species. Upolu power supply. There are likely major impacts of the project that need to Recent studies have considered the be addressed prior to the commencement operation of the Tanugamanono of the project, some will require further powerstation to be increasingly non-viable studies to dercrmine the likely effecm. as a major diesel generating facility. This environmental assessment snrdy identified The divenion canal will drain that proper disposal mechanisms for waste approximately 33 percent of surface water oil and water have not been operarcd from the Alafou village area which already adequately. There arcvery high levels of has water problems. The project must noise and exhaust fumes pollution rc the make sure the existing streams are not nearby households which are drained out completely as the villagen unfornrnately,very close to the depend on the $ream flow for their water powerstation. The installation of another supplies. Also once the srream beds and diesel generator is considered to cause pools are allowed to dry out then dl minimal impacts depending on how the marine life dependent on this water supply Tanugamanono powerstation strucnrred will be affected and may be destroyed some impnvement schemes priorto the altogether. The Alafou villagers should be new instdlation. The waste oil reduction compensated for the loss of surface water plant should be operated efficiently and an and it is recommended that the project efficient waste oil collection and disposal prrrvides a simple but reliable srater systrm system should be implemented for the village. Providing a reliable water immediately. The noise pollution can be source for the village might provide abated by installing a new silencer with an incentives during negotiations, for the efficiency to reduce exhaust noise to villagers to give consent to the use of their approximately 45 decibels at the boundary land to lay the divenion canal. fence. The height of the fume staclc should be raised to ensure the exhaust fumes are The increased constant flow of fresh water dispened at a much higher level than the at the Ta'elefaga tailrace into Fagaloa Bay nrof tops of nearby houses. could possibly have negative envircnmental tx
GLOSSARY
The following explanations are provided for the lay reader. They are nor inrended to be scientificdly precise.
Algae Very simple plants Anaerobic Lacking in oxygen DAFF Department of Agriculrure, Forestry Fisheries ^nd dBA The average loudness of a noise source (measured in decibets) DEC Depanment of Environment and Conservation DO Dissolved Orygen (measured in milligrams per litre)
EIA Environmental Impact Assessmenr
EPC Electric Power Corporation of Samoa Fauna Animals Floc A flocculent mass of fine particles Flora Planm
GIS Geographic Information Systems
G\fh Giga \Vatt hour, a measure of rhe mtd power produced over a period of time, 1000 megawart hours Montane Occurring in mountains
MlUf Mega'\0flatr, a unit of povrer, 1000 kilo watrs Ogee Arch An arch with two ogee curves meeting at the apex pH A measure of acidity and alkaliniry a scale from 0 (most acid) to 14 (most alkaline) ppm Parts per million, one ppm : one gram per cubic metre Saliniry A measure of saltiness
SL Sea level height, normally cdculated as height frorn the mean sea level
SPREP South Pacific Regiond Environment Programme
Tailrace Canal leading rhe milrace waters from the turbine engines
Turbidity Cloudiness in rhe warer
USP Univeniry of the South Pacific
INTRODUCTION
1.1 The Project 8M\f of diesel and about 12MV from the five hydro power plan*. The ourput The Afulilo Hydro Electric Power of the hydro power schemes though is Development began in 1991. The seasond, resulting in total hydropower construction work took about two years generation peak capabiliry dropping from until March 1993, when the dam was a we[ season high of approximately closed and the reservoir began filling. 11.5M'$tr to about 6M\f in rhe dry The Afulilo scheme is a hydro electric season. The Afulilo storage scheme storage scheme, it has an insralled provides most of rhis capacity during the capacity of 4M\[. The dam was built ro a dry season. Consequently, diesel sea level heighr (SL) of SL 317.50 merres, generation needs to be increased in the the fulIsupply level, which would hold dry season to make up for the deficit in 10 million cubic metres of water srorage hydro porver production. which would allow, wirh good management, maintenance of 4M\0f The proposed augmentarion project of output throughout the dry season. The the Afulilo hydro pov/er scheme consist dam has been spilling intermirtently from of the following: late December 1993 therefore, there is i) installation of a third 2 MV potential for conrinued steady and or hydroelectric turbine at Ta'elefaga enhanced outpur at the Ta'elefaga povrer power station; plant to supplemenr diesel power generation. ii) raising the Afulilo damby 1.7 metres; Tanugamanono power station near Apia, provides an installed diesel power iii) construction of an eastern capaciry of approximately 11M\f. Due to diversion canal to divert more water into the age and technical facrors, the diesel Afulilo reservoir; and generators have been down-rated and as a consequence, the station capacity is iv) installarion of a currendy about 8.7MrV. The Upolu new 4 MW diesel genentor at the Tanugamanono electricity system has a maximum diesel generating capability of approximately power plant.
1.2 EIA Brief
The South Pacific Regional Environment Project. The terms of reference for this Programme responded to a request from EIA are: the Ministry of Foreign Affairs of Samoa, tVith to assist in the prepararion of an Environ- A regard to the existingAfulilo mental Impact Assessmenr (EIA) of rhe lrydropouer scheme Afulilo Hydrcpower Augmentation Aagrnentation Project of the Afulilo Hydro Poater Scheme
1. Review the recommendations set out 3. Address any discharge and seepage in the EIA report of.1997 that may occur from the generator
2. Determine any outstanding issues 4. Consider exhaust emissions that need to be addressed 5. Consider impact of the cooling 3. Provide a proposal for mitigating systems utilising water syst€ms measures if required 6. Consider fuel storage for the B lf/ith regard to tbe Afulilo generator Augmentation project 7. Provide a proposal for additional L Determine the effects of the increased mitigating measures if required surface arrea of the Afulilo reservoir with the raising of the dam This EIA document is intended as an aid to decision making on the augmentation 2. Consider additiond noise at the phase of the Afulilo scheme. It presents Ta'elefaga power station with the summary information to better third turbine to be instdled understand the effects of the scheme and make recommendations on actions which J. Determine the additional overflow of could be taken to reduce the impacts. water into Fagaloa Bay resulting from the installation of the third turbine The report reviews both the effects of the scheme, and an eadier environmental 4. Determine the effect of water being assessment carried out by \7augh et al in diverted away from natural water 1991 prior rc the construction of the courses into the reservoir Afulilo scheme. The repon incorporates material frrcm field investigations C lVith regard to tbe proposed neat diesel conducted by the authors in May and generdtor Jr:Jy 1997, but extensive use is also made of materials drawn from the Afulilo 1. Determine the additional noise to augmentation and inception documents, surrounding villages the corporate strengthening reports, and the \Vaugh assessment. 2. Consider water and lubrication oil seParation and treatment
1.3 Background
The country of W'estern Samoa, now its relatively substantial hydropower called Samoa, depend on biomass for resources are constrained by low dry about 55 percent of its energy needs and season capabiliry and limited storage on petroleum impons and electricity availability. generation for its commercial enerry requirements. Petroleum products The responsibility {or public electric account for one third of energy usage and power generation, distribution and sale of hydro electricity geneftrtion makes up the electricity in Samoa rests with the remaining balance of two percent. Samoa Electric Power Corporation which was have no known petroleum reserves and established under the EPC Act oI 1972. and is wholly government owned. It is future. Vith the exception of the Afulilo governed by a Board chaired by the stomge scheme, Upolu hydro generation '\Jflorks. Minister of Public EPC is is highly seasonal and additional firm managed by a General Manager, a energy capacity is urgently required. Peak Deputy General Manager, a power demand for the Upolu system in Development Engineer and a Generation December 1996, was l2M't$f and energy Engineer. genention for the year was 69 G\fh.
In Upolu, EPC operates the largest power There has been a significant increase in system which in March 1992, consists of: power demand in the Upolu system. Developments associated with Yasaki . installed Hydro Plant (4M\[ "12M1V expansion of its electrical wiring long-term storage and 8M\f run of assembly plant, signing of memorandum river) of understanding for the establishment of an international class hotel at lotofaga . (down "8M'W installed Diesel Plant and a possible tuna cannery indicated rated from 11M\0. that the load growth would be higher Much of the diesel plant is derated due to than previously estimated at five percent age and mechanical restrictions, and will Per annum. be retired progressively in the near
1.4 Review of Recommendations of the 1991 EIA Report
The various issues of the Afulilo scheme result in t loss of the last large highlighted in the \fl'augh environmental montane ^grewetland in Samoa. The report assessment report have been addressed also weighed the loss of the Vaipu swamp with varying degrees of success, the main m be a very high price to pay for the areas of concern are discussed here. relatively small gain in extra power generating capacity. 1.4.1 The Vaipu Scheme The Afulilo hydro scheme was designed The strong recommendation made were: and constructed with provisions for the serious consideration of the natural additional water available from the Vaipu values of the Vaipu swamp is discussed swamp area. The intention was to install before a decision is made on the Vaipu this third turbine machine when the load scheme; that no work be permitted in the had grown sufficiendy and that the Vaipu Vaipu swamp; that the DEC secure long- scheme was developed. term protection of the Vaipu swamp; and that DEC conducts an inventory of flora The environmental assessment report and fauna of the Punataemo'o basin noted that formation of the ponding area (Afulilo scheme) before these populations is destroying the Punataemo'o swamp are destroyed. which was one of the most important natural areas remaining on Upolu. The The EIA report plus other documented only other such area in Samoa is the concerns, have successfully influenced Vaipu (Fusiluaga) swamp immediarcly the decision makers to abandon the downstream. Future extension of the Vaipu scheme proposal. The Afulilo Afulilo scheme suggested pumping water augmentation project is now considering, from the outflow of the Vaipu into the and will be discussed in depth later in the headrace conduit. The report considered next chapter, an eastern diversion canal that the proposed Vaipu extension will which would bring more water into the Aagrnmution Project of the Afultlo Hydro Power Scheme
2 THE AFULILO AUGMENTATION PROJECT
2.1 Raising the Afulilo Dam
The surface drainage into the Afulilo The acrual specification for the increase reservoir has surpassed expectation and in dam wall height was dekrmined after has resulted in the dam overflowing examining of a range of options. The intermittently during 1993 to 1996. The Project Feasibiliry Study identified the reservoir (see Figure 1) and the whole best option as that of raising the dam Afulilo hydropower scheme was initially spillway crest level by 1.7 metres to SL established to supply power5furing the 319.2 merres. This new sea level height dry season when the run-on-river systems will increase the Afulilo storage volume were affected by low water flow in the from 10 million cubic metres to 15 rivers. However, the reservoir level has million cubic metres, i.e. an increase of been sufficiently high that the Afulilo 50 percent. Raising the crest is hydropower scheme has been used accomplished with a reinforced concrete continuously since it began operating in ogee crest extension that is joined onto March 1993. The potendal for much the existing crest. The bridge deck will be larger volumes of water draining into raised by 0.5 metres to SL 320.9 metres Afulilo reservoir than is currently catered which would represent a flood event with for has prompted the need to raise the an annual event probability of 1 in dam. According to Mr M. Nation water 10,000 year design flood. The potential lost over the dam wall is lost power effects of such an increase on the surface resources and lost revenue to the Electric area of the reservoir is one of the Power Commission. environmental concerns for the Afulilo augmentation project. Figure 2 shows the new surface area of the reservoir.
2.2 Installation of third turbine at Ta'elefaga Power Station
Currentln there are two turbines Installation of the third rurbine at the operating at the Ta'elefaga Power Station. Ta'elefaga Power Station has implications However, there is already basement and for the environment. Noise pollution tailrace outlet for a third turbine. Having levels may increase from the current three turbines allows, any one of the levels if all three turbines are in use. turbines to be taken offJine for Additional volume of fresh water would maintenance, and for other reasons) be discharged at the tailrace and this without disrupting the scheme operation. would affect the stream flow, water At the same time, the option of having quality conditions in dre stream, and all three turbines operating is always Fagaloa Bay. available and whenever the need arises. It is most likely that all three turbines will be run full time. and is wholly governmenr owned. It is future. \[ith the exceprion of the Afulilo governed by a Board chaired by the storage scheme, Upolu hydro generarion Minister of Public \florks. EPC is is highly seasonal and additional firm managed by a General Manager, a energy capacity is urgently required. Peak Deputy General Manager, a power demand for the Upolu system in Development Engineer and a Generarion December 1996, was 12MW and energy Engineer. generation for the year was 69 G\fh.
In Upolu, EPC operates rhe largest power There has been a significanr increase in system which in March 1997, consists of: power demand in the Upolu sysrem. Developments associared with Yasaki . installed Hydnr Planr (4Mu7 "12M'W expansion of its electrical wiring long-term stomge and SMuf run of assembly plant, signing of memorandum river) of understanding for the establishment of an international class hotel ar Lotofaga . installed Diesel Plant (down "8M'W and a possible tuna cannery indicated rated from 11M\0. that the load growth would be higher Much of the diesel plant is derated due to than previously estimated at five percenr age and mechanical resrrictions, and will Per annum. be retired progressively in the near
1.4 Review of Recommendations of the lggl EIA Report
The various issues of the Afulilo scheme result in a great loss of the last large highlighted in the Vaugh environmenral montane wetland in Samoa. The report assessment report have been addressed also weighed the loss of rhe Vaipu swamp with varying degrees of success, the main to be a very high price to pay for the areas of concern are discussed here. relatively small gain in extra power generating 1.4.1 The Vaipu Scheme capacity.
The Afulilo hydro scheme was designed The strong recommendation made were: and constructed vrith provisions for the serious consideration of the natural additional water available from the Vaipu values of the Vaipu swamp is discussed swamp area. The inrention was ro install before a decision is made on rhe Vaipu this third rurbine machine when the load scheme; that no work be permined in the had grown sufficiendy and rhat rhe Vaipu Vaipu swamp; that the DEC secure long- scheme was developed. term protection of the Vaipu swamp; and that DEC conduc$ an inventory of flora The environmental assessment report and fauna of the Punaraemo'o basin noted that formarion of rhe ponding area (Afulilo scheme) before these popularions is destroying the Punataemo'o swamp are destroyed. which was one of rhe most important natural areas remaining on Upolu. The The EIA report plus other documented only other such area in Samoa is the concerns, have successfully influenced Vaipu (Fusiluaga) swamp immediately the decision makers to abandon the downstream. Future extension of the Vaipu scheme proposal. The Afulilo Afulilo scheme suggested pumping water augmentation project is now considering, from the outflow of the Vaipu into the and will be discussed in depth later in the headrace conduit. The reporr considered next chapter, an eastern diversion canal that the proposed Vaipu extension will which would bring more water into the Augmmtation Project of the Afulilo Hydm Pouter Scheme reservoir by gravity-feed, from the indication that initial trials with sterile southern and eastern areas of the Afulilo fish will be conducted. The Fisheries catchment. There is some documentation Division has conducted trials of the new of the plant and animal species strand of Tilapia since 1991 in various population of the Punataemo'o basin areas of Samoa and therefore, probably prior to its inundation. The major felt it unnecessary to direct another trial management decision on the Protection at Afulilo. Nevertheless, it is important of Vaipu swamp include the whole lona- that Fisheries Division undertake first, a Punataemo'o area has already been full EIA of Tilapia farming in Afulilo initiated with several conservation studies reservoir to better undershnd the likely currently being conducted by DEC and effects this proposal will have on the SPREP. surrounding environment. 1.4.2 Exotic species 1.4.3 Ta'elefaga operation The only lake weed present in Samoa The generators for the hydro power capable of seriously affecting the scheme are located in Ta'elefaga village. operation of the hydro scheme is water Noise levels were not recorded to hyacinth. This exotic water plant is not determine the acceptable standards (there found in the Afulilo area and EPC is is no noise standard in Samoa). However, monitoring its spread to ensure it does the EPC's operating procedure at the not affect the hydro scheme. Ta'elefaga power plant is to close the sliding door during night time in order to noise levels to the nearby It has been suggested that the reservoir be minimise procedure used for aquaculmre. The environmental houses. This noise abatement satisfactorily. assessment repoft recommends that appears to be working exotic fish is not to be introduced into 'Water the Afulilo basin. This is because any from the powerhouse is introduced species in Afulilo basin is discharging into the stream which flows bound to find its way through over- through the Ta'elefaga village. The spillage at the dam, to the Vaipu basin amount involved is substantially more downstream. There is the concern that than the natural low flow of the strearn. Vaipu basin may be one of the few areas Most of the time, the water is discoloured remaining in Samoa which is free of and has an unpleasant smell. The introduced fish species and therefore, the villagers were not made aware of these need to protect this and surrounding likely changes at the early stages of the areas from exotic fisheries. hydro power scheme. There was a fatal accident of a small boy being washed During mid-1996 the Fisheries Division down the stream and drowned in the bay. conducted various water quality tests in The stream sides are novr fenced off to the Afulilo reservoir for the purpose of avoid similar incidents, but the increased {ish farming and stocking of a Thailand warcr flow is causing frequent strain (Chitralada) of the Nile Tilapia, overflowing onrc the bridge and still Oreochrotnis niloticus, which was poses danger for villagers crossing. introduced to Samoa in 1991. This exotic Upgrading this bridge should be species was to help remove and/ or undertaken by the proper authorities as a improve the strain of the "rubbish fish" matter of urgency. African Tilapia, Orechrornis mossambica, which was introduced during the 1960s The clarity of the water is still regarded villagers (see record of Q.ann,1992). The Matsunaga and Bell, as "dirty" by the 1996 report on "Potential of afulilo village meeting at Annex 1). There has Reservoir for Fish Stocking" gave no been a "promise' by EPC to build a swimming/washing area above the Bay. From the village meeting held on 28 taihace, using the normal stream flow. [t May t997, there appears to have been is recommended that this is undertaken little consultation with the villagers by by EPC prior to the commencemenr of EPC on the proposed Afulilo project, the augmentation project. It is also and its potential effects on the marine recommended that serious consideration resources around Fagaloa Bay. At leasr no be given to providing a holding pond to documented evidence of a consulmtive divert the tailrace flow m settle sediments process is available. Even the rVaugh and other particles, prior to discharge environmental assessment report provides into FagaloaBay. The holding pond can no records of meetings with Ta'elefaga be cleaned out periodically and should villagers which probably explains the help reduce the inundation of the reef lack of consideration for social impacr flat and pools with silt particles but, also monitoring in the 1991 report. limit the extent of the plume within Fagaloa Bay. Public consultation is crucial for this imponant 1.4.4 Social impacts project. EPC should conducr a public meeting with the villagers prior to The Afulilo scheme has significant social the commencement of the Afulilo effects particularly to rhe Ta'elefaga augmentation project. Even if EPC did village communities hosting the not acquire anything new fn:m thar powerhouse with its discharge of tailrace meeting, the exercise should foster water into the stream in the middle of the goodwill and support of the project by village and flowing down into Fagaloa the villagers. Augmmtation Project of the Afulilo llydrc Power Scheme
2 THE AFULILO AUGMENTATION PROJECT
2.1 Raising the Afulilo Dam
The surface drainage into the Afulilo The actual specification for the increase reservoir has surpassed expectation and in dam wall height was determined after has resulted in the dam overflowing examining of a range of options. The intermittently during 1993 to 1996. The Project Feasibiliry Study identified the reservoir (see Figure 1) and the whole best option as that of raising the dam Afulilo hydropower scheme was initially spillway crest level by t.7 metres to SL established to supply power6furing the 319.2 metres. This new sea level height dry season when the run-on-river systems will increase the Afulilo storage volume were affected by low water flow in the from 10 million cubic metres to 15 rivers. However, the reservoir level has million cubic metres, i.e. an increase of been sufficiently high that the Afulilo 50 percent. Raising the crest is hydropower scheme has been used accomplished with a reinforced concrete continuously since it began oPerating in ogee crest extension that is joined onto March 1993. The potential for much the existing crest. The bridge deck will be larger volumes of water draining into raised by 0.5 metres to SL 320.9 metres Afulilo reservoir than is currently catered which would represent a flood event with for has prompted the need to raise the an annual event probability of 1 in dam. According to Mr M. Nation water 1O,OOO year design flood. The potential surface lost over the dam wall is lost Power effects of such an increase on the resources and lost revenue to the Electric area of the reservoir is one of the Power Commission. environmental concerns for the Afulilo augmentation project. Figure 2 shows the new surface areaof the reservoir.
2.2 Installation of third turbine at Ta'elefaga Power Station
Currently, there are two turbines Installation of the third turbine at the operating at the Ta'elefaga Power Station' Ta'elefaga Power Station has implications However, there is already basement and for the environment. Noise pollution tailrace outlet for a third turbine. Having levels may increase from the current three rurbines allows, any one of the levels if all three turbines are in use. turbines to be taken offline for Additional volume of fresh water would maintenance, and for other reasons' be discharged at the tailrace and this without disrupting the scheme operation' would affect the stream flow, water At the same time, the option of having quality conditions in the stream, and all three turbines operating is always Fagaloa Bay. available and whenever the need arises. It is most likely that all three turbines will be run full time. 2.3 Diversion of surface water into the Afulilo Reseruoir
Diversion of water from narural because of concerns wirh the geology and waterways into reservoirs for the purpose topography of the other potenrial sites. of generating hydropover is a common The East Canal, shoqrn in Figure 3, will phenomena. However, the effects of divert run-off from rhe norrhern slopes divening warer eway from existing uses of range exrending east .from Mt Savai'i. and users must be clearli' identified and The proposed canal would intercept assessed. several prominent surface streams, at the foot of the ranges, and could produce an A number of diversion canal options estimated 35 percent in yield for the were identified but, rhe oprions were Afulilo storage. nanowed down to the East Cand only
2.4 Installation of new 4Mw diesel generator at the Tanugamanono Power station
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3 EXISTING ENVIRONMENT
In this chapter the current environmental temperature, dissolved oxygen, clarity, situation of the Afulilo hydropower salinity and pH.'Water samples were scheme is reviewed, four years after it was collected from these locations, taken m commissioned in 1993. The review the laboratory at USP Alafua Campus in includes water qualiry studies, noise level Apia to stabilise them before airfreighting measurements, fauna and flora studies, the samples out that wening to the USP, and social effects of the project. in Fiji for laboratory chemical analysis. Parameters analysed for in the laboratory Particular emphasis was given to the included: total and dissolved iron and current water quality situation which was manganese; and nutrients, nitrates and assessed in the reservoir, in the creek phosphates. Some assessment results are above the tailrace, in the creek just below tabled below but full records are attached the tailrace and in Fagaloa Bay. as Annex 2. Parameters assessed included water
3.1 The Afulilo Reservoir
The Afulilo Hydro Power Development smell could be detected during the two began in 1991. The dam was closed off in site visits. March 1993 and by July 1993, the first 3.1.1 Water quality in the reseruoir test run of the whole scheme was carried out. The reservoir continued to fill and The quality of the water in the Afulilo in mid-October 1993, the reservoir began reservoir was assessed on two occasions at to spill when the level exceeded the two stations. The first site visit and water maximum supply level of SL 317.50 quality study was conducted on 20 May metres. Daily records of the reservoir 1997, and the second on 28 May 1997. levels indicated that the reservoir One station was near the dam wall and continued to spill from mid-October to the other station was located further to late November 1993, and again the north of the wall. Figure 1 shows the intermittently from late December 1994 location of the two s/ater qualiry study until early March 1995, 1996, and 7997. stations in the reservoir.
The reservoir level during the field work At each site, measurements were taken of on 20 May t997,was SL 316.4 metres. temperature, pH, water clarity and One week later on 28 May 199l, the level dissolved oxygen. The water depth near had dropped to SL 316.0 metres. During the dam wall was five metres and clarity the two weeks from 77-29 May, when the measured using a secchi disc was one field work was being conducted, very metre. Near the dam wall, the profile of little rain fell in Apia. The water in the temperature and dissolved oxygen was reservoir was a diny brown, but no foul measured using the YSI Model 5/ Augmentation Project of the Afnlilo Hydro Pawn Scheme T2
Oxygen Meter. \fhile the water were preserved for transportation to the temperature was relatively constant with laboratory at USP for analysis. The depth, the concentration of dissolved elements of inrcrest in this situation are oxygen (DO) quickly decreased. At three iron and manganese, and both total and metres below the surface, the DO levels dissolved iron and manganese were had dropped below 5 mg/l,the minimum analysed for. The results showed no required for aquatic life. Near the bottom significant difference between the surface the DO was a low 2.6 mglI. Such and bomom concentrations of these depleted DO levels indicated that a high elements. There was also no significant percentage of organic matter are at difference between the two stations at the various stages of decomposition. Table 1 reservoir. lists the water quality measurements at Afulilo reservoir extracted from the full 'Water samples were collected during the table of water quality assessment results second visit on 28 May for nutrient tabled at Annex 2. analysis. Results showed that both nitrates and phosphates'q/ere very low, in Vater samples were also collected from fact below the detection limit of 34 ug/l near the surface and bottom close to the for nitrates and below 20 ug/l Ior dam wall, and from the surface in the phosphates. Full results of the analysis second station. The samples collected are attached as Annex 2
Thble 1: Afulilo Reservoir'Sl'ater Quality Measurements
Date GPS Profile Time T.*p DO pH Clarity Location Depth ftr) (0c) tue/l\ (metres) 13 58.100 S 20/05/97 t7133.665U| Surface0m 1328 26.5 7.4 6.00 I 11m 26.4 7.2 22m 26.0 6.4 3lm 25.5 4.8 44m 25.5 4.7 55m 25.5 2.6 5.79
20/0s/e7 13 58.013 S 100m west of 1410 27.5 7.8 7.40 NA dam in 30cm 171 33.684 V water depth
3.2 Ta'elefaga Power Station
From November 1993, both machines at all occasions, the plant v/as neat and tidy the Ta'elefaga power station have been in and both machines were fully operation continuously with minimal operational. The plant was well guarded problems. It is noted that since the and the attendant was always helpful commissioning of the Afulilo hydro when questioned. pov/er scheme, which took up 3.2.1 Noise emrssion approximately 70 percent of generation shares, diesel fuel consumption by EPC Noise levels were recorded inside the has dropped dramaticdly by about the plant, and outside in one of the nearest fale local house, same Percentage. or during the day and also at night. Noise levels ranged from 48 The power station was visited four times dBA (fale at night), to 92 dBA (inside during the two week field study, and on plant, during the day with two turbines IJ
operating). The current continuous noise averages 80 dBA. Vearing of ear Ievel inside the plant is a high 92 dBA protection should be enforced now, and therefo re, ear protection gear must be before installation of the third turbine. worn at all times by the attendant(s). Noise levels outside the plant were Samoa does not have specific reduced significantly when the sliding Occupational Health and Safery door was closed. Noise levels recorded at Guidelines but as indicated in Section Ta'elefaga power station and village are 3.5.5, it is common practise to wear ear shown in Table 2 below. protection at work places where the noise
Thble 2: Average Noise Measurements at Ta'elefaga Power Station
Date Time Iocation Noise Level (dBA) 23/5/e7 L4t5 Inside Ta'elefaga Power Station (door open) 92
23/5/e7 r4t7 Outside power station at the fence, 15 metres from open door 66
23/s/97 141 8 15 metres outside power station at the fence, with door closed 58
23/5/97 2204 Inside power station, door closed 87
23/s/97 2207 At fence 15m with door closed OU
24/5/97 0200 lnside fale (house), 25 metres away 48
3.3 Ta'elefaga creek
The Ta'elefaga creek which now receives The quality of the water in the creek water from the tailrace has changed above and below the tailrace was dramatically from what ir was prior to examined during the site visits. The same the Afulilo scheme. Water flow in the parameters were also assessed in Fagaloa creek from the tailrace to the bay was Bay just in front of the village. Water quite rapid and the resultant current at samples were also collected from these the culverts was srrong enough to c^rry sites and transferred to USP for analysis. off a toddler into the bay. This is one risk The samples 'were analysed for iron and that must be addressed immediately manganese, and the nutrients nitrates and before implementation of the phosphates. The water quality resr results augmentation project. At the moment, are attached as Annex 2. Comparison of there is no adequate fencing ar rhe bridge resulm for iron and manganese showed to prevent accidental falls into the creek, that water discharged at the tailrace particularly for children. contained significantly higher concentrations of both total and No fauna could survive the fast flow and dissolved iron and manganese than rhe the water was distinctly brown. Although natural creek water above the tailrace. Of not obvious during the study, the interest is the fact that levels in rhe water villagers had indicated thar rhe creek had from the power plant are almost identical often had a foul smell at times. This to that in the reservoir. The Afulilo would be consistent with rhe situation reservoir is definitely a source of iron and when organic matter decomposition took manganese in the creek and ultimately in place under anoxic condition. Fagaloa Bay. Levels of nutrients were all I4 Augmentation Pmject of the Afulilo Hydro Power Scheme
low except in the creek above the tailrace. farming in the households further up the The high nitrate in the creek Y/ater may road. be attributed to the intensive vegetable
3.4 Fagaloa Bay Fagaloa Bay is a semi-enclosed bay colour with much lower pH than the bordered by a number of villages receiving water. The salinity remains low including Ta'elefaga at the head of the for some dismnce out into the bay. bay. The bay is relatively well-flushed by However, the concentration of iron and the tides and a number of freshwater manganese, and nutrients are lovr and no streams and creeks drain into the bay. different from the other study sites. 3.4.1 Water quality 3.4.2 Social conditions Observation of the current situation The near-shore area was walked during indicate that a large amount of fine, low tide to assess the range of organisms suspended parriculate matter is being in the intenidal zone. The local villagers added to the bay everyday The water were interviewed on types of fish leaving the tailrace is definitely brown in gathered and changes that may have colour and this forms a plume for some occurred since the commissioning of the distance into the bay. The origin of this Afulilo scheme. The villagers noted that coloured water is the flooded swamP the "atule" fish, a seasonal fish, is no which now serves as the Afulilo longer available in the bay. Table 3 shows reservoir. Although not encountered the type of fish species that are now during the field study, an associated effect absent from the bay. of the swamp water is the smell of rotting organic matter under anoxic conditions. The disappearance of these species could This problem was highlighted by the be due to over-fishing particularly the villagers to the study rcam during the shellfish, but it is evident from the large village meedng held at Ta'elefaga village number of dead juvenile shellfish that the (see Annex 1). new flow regime at Ta'elefaga stream and sedimentation, have affected the fishery Fagaloa Bay was sampled on two resources at Fagaloa Bay. occasions by measuring a number of water quality parameters on site and The 1991 EIA report recorded the collecting water samples for chemical number of people at Ta'elefaga to be 500 analysis at the USP laboratory. Full people. The 1997 population figure given details of water quality measurements are by the Statistics Department in Apia is attached as Annex 2. The freshwater now 132. The probable cause of the from the power station is a dirty brown decrease in population at Ta'elefaga could
Table 3: List of fishes now absent from Fagaloa Bay
Samoan Name English Name Scientific Name
Atule Purse eye scad Se lar cr urn en ohh th al m us Alili Turban shell Thrbo chrnsostomus Tugane Venus shell Gafrarium st, Fole Pen shell Pinna sD. Gau Green sea hare Dolabella auiculaia Fatuaua Thorny oyster Spondylus sp. Iultut Boring urchin Echinometra rnatthaei 1t
be migration overseas (normd for the marine resources at Fagaloa Bay. This Samoans) and into urban Apia. The will determine the rrue cause of the village popularion level should be changes observed at Ta'elefaga. monitored togerher wirh monitoring of
3.5 Diesel Generation at Tanugamanono power Station
Although not strictly an Afulilo be viable as a major generaring facility. augmentation oprion, the installation of That report recommended a new diesel an additional diesel plant at power station at Vairele industrial area. Tanugamanono station is an essential Relocation of diesel generarion should be component of the development of the the subject of a later study and will not EPC generation sysr€m. The current be discussed here. environmental situation of diesel Fuel storage generation is discussed in this section. 3.5.2 and fire risk Fuel is stored at the power station using 3.5.1 The diesel power station rwo tanks with capacity for 20,000 and A number of processes are required m 40,000 gallons. These tanks are elevated operate and maintain the power station. on stands outside, at the back of the In general terms rhese include: generating complex which is approximately less than 20 merres from . the actual process generating of the the nearest household. There are a electricity through the rurning of rhe number of hazardous materials being alternarors by diesel- or fuel oil- used and stored on the power station and powered motors; therefore, there will always be a fire risk. Diesel and oil spill fires at diesel plants . a fuel storage area site on to provide are uncommon (the fuels used have a regular fuel to run the motors; high flash point and rherefore are . relatively safe, being difficuh to ser alighr auxiliary systems such as cooling and not prone ro explosions) but the systems, exhaust systems and potential for fire is rhere and also '$flaste may be lubricating sysrems. oil system caused through elecrric failures, of collection, srorage and off-site transformer explosion and other normal processing should also be in industrial risks. operarion. Electric control systems monitor and operate the motors; and The proximiry of the power starion to the Tanugamanono village poses a . fire systems are provided in rhe form serious threat to human lives and of fire hydrants in various locations property in the event of a fire at the within the building. station. The fire hydrants installed around the station is not sufficient. A The Tanugamanono power station in its comprehensive fire sysrem should be present location is not totally free of installed to include also a fire ring around problems. The Hydro Electric the site with hydrants, as well as sprinkler Comrnission Enrerprises Corporation systems and fire extinguishers in various (HECEC), Ig97 report identified that the locations within the buildings. Tanugamanono site will eventudly not Atgmenation Project of the Afulilo Hydro Power Scheme 16
3.5.3 Coolingsystem through the upstairs bedroom window of The present, cooling system is heavily the nearest house. dependent on water supply piped down from one of the run of river hydro power Aloise schemes. The water supply is often 3.5.5 ernrbsion insufficient particularly during the dry Noise levels and other observations were season and more often than not, the EPC recorded during the site visit of the has to tap into the municipal reticulated Tanugamanono power station on 21 May water system for its requirements. Each 1997.Table 4 shows the high level of water cooled generator consumes noise within the plant itself and outside. approximately 4,000 litres of water per It was noted that most employees hour and even with only one of the five working in the contrcl room, which had generators running there is continuous a sound recording of 8+ decibels, were problem of insufficient water supply. not wearing ear protection. It is standard Currently, additional water required is practice to use ear protection devices normally purchased and brought into the while working around running plants. As station by water trucks from thel0ilater shown in Table 4, most work areas Authority. exceeded the 80 dBA level, often regarded as the minimum acceptable noise level in 3.5.4 Waste oil and Exhaust Fumes work places, and therefore employees There is approximately 50 barrels of should be encouraged to wear ear waste oil produced every six months. protection devices at all times. This equates to about 700 litres of oil per month. The power station aPPears to Noise emission from the generators has have no proper disposal system for waste been and continues to be the main cause oil. It is believed that most of the waste of social discontent for some villagers at oil is drained down the hillside into the the Tanugamanono area. The main valley and river below. Complaints have complaint has come from the owner of been received by DEC from villagers the nearest household, who has officially below that the river is often lodged his complaint against noise contaminated with oil from the power pollution with the Department of plant-an indication that waste oil is Environment and Conservation in July actually allowed todrain down the 1997.The noise level taken at 2245 on hillside. the 21 May 1997 inside a bedroom of the complainant's house was 70 dBA. This Exhaust fumes were not measured during level is much higher than the the study, but apart from the standby recommended New Zeilandstandard of generator, all exhaust fumes are expelled 45dBA at the boundary for noise through the 20 metre tall exhaust stack produced continuously at night. which just clears the top of the double storey building next door. Current noise emission is at an unacceptable level and EPC should The Tanugamanono station is located maked changes immediately. The within a village, the houses surrounding immediate short term option would be to the power plant are quite close and there reduce the noise emission by replacing have been major complaints about the the current inefficient silencer with a noise and fumes emanating from the new one capable of reducing the noise power plant. Table 4 records that at level to about 40dBA at the boundary certain wind directions, exhaust fumes fence. from the power station are blown directly 17
Thble 4: Average Noise Measurements at Tanugamanono Diesel Power Plant
Date Time Location Noise Lerrl Remarks (dBA) 21/5/97 3.00pm Outside Mmin. Building 75.0
21/5/97 3.10pm Jtst outside of powerplant 86.0
21/5/97 3.15pm Transforrrn rs station (seded 77.0 off from generaton)
21/5/e7 3.20pm C-orridor, ovedooking 84.0 'Wo*en w[hout genenrtorsr sealed off ear protecdon.
21/5/97 3.25pm Inside main genenting area r 01.0
2r/5/97 3.3Opm Cutside plant, eastem end 93.0
21/5/97 3.35pm ]utside, near cooling tower 88.s
2t/ 5/97 3.40pm ]utside, near radiator fans 98.0 Added fan noise
2r/5/97 3.45pm Eastem side of plant, 78.0 15 netres from towands the fence- mechanic's house
,_t/5/97 10.40pm Berween power plant and 66.0 nrchanic's house 'tr/5/97 10.45pm tfustain, inside bedroom 70-0 Vibratiors felt adjacern to power plant rhrough house.
2t/5/97 10.5Opm Llstairs, in funhest room 62.0 Exhaust srnclie fiom power station got irao uptairs rooms
2r/s/97 1 l.00pm Outside at backprd of 65.0 nrchanic's house 21/5/97 I l.15pm On road side near house at 55.0 Approx. 20 hack of Admin. Office metres wesc of plant.
In the absence of noise guidelines, Figure 4 below is provided to give some examples of sound intensities for comparative pulposes with the sound measurements talcen at Ta'elefaga and Tanungarnanono.
Figure 4: Sound Intensities
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4 ENVIRONMENTAL EFFECTS OF THE AUGMENTATION PROJECT
4.1 Increasing Afulilo reservoir volume
The proposed increase in height for the 4.1.1 Land tenure dam wall is 1.7 metres. This increase The land that will be flooded by the would result in raising the maximum proposed raising of the dam is within the supply level from SL 317.5 metres to SL boundary of land taken over by the EPC 319.2 metres. The Afulilo dam will now for the Afulilo Hydro power scheme. impound up to 15 million cubic mgtres The government of Samoa acquired this of water at the maximum normal land by Proclamation of 27 July 1988, operating level of SL 3I9.2 metres. and landowners have been compensated Afulilo lake surface area at this new level for the compulsory acquisition of their will be approximately 270.a hectares (see lands. The area is fenced off and, except Figure 2) an increase of 19.4 hectares. To for grazngcaftle, there is no other determine the effect of this increased activities in the area. Land tenure storage at the reservoir, it was necessary therefore is not an issue with the to mark out the new SL 319.2 metres expected surface area increase. Before the contour around the existing reservoir work begins however, the grazing of boundary which currently stands at SL caftle on the grasry flat banks close to the 317.5 metres, the maximum attainable road must be stopped. with the present dam specifications. 4.1.2 Flora and Fauna The new water level (SL 319.2 metres) of Due to the uneven height increases all the reservoir was calculated from the 325 around the boundary of the existing metre contour and the current water level Afulilo reservoir, the surface area to be (SL 317.5 metres) using the 1:10,000 flooded will be much greater on the topographic engineering plan No. 83417 banks adjacent to Richardson road, than from the Electric Power Corporation, in at the foot hills to the north of the Apia. The position of the new level was reservoir. Nevertheless, much of the flat plotted on the same topographic plan and area that will be flooded is covered with then digitised for mapping purposes and grass and gnz.ed by some cattle, with data analysis. The surface areas of the occasional bushes of "fau' Hibiscus two water levels were calculated using the tiliaceus, on slightly higher ground. On ArcView 3 software programme. The the other hand, the srceper northern new water level was also checked by banks of the reservoir have more differentid levelling using an automatic vegetation, including a diverse level instrument. This is to get a clear community of tree species such as the indication on the ground of the proposed "laufatu" Macaranga stipulosa and palm level. 5L319.2 metre water trees "niu vao" of the Clinostigrtd sp. T9
Other trees found include the "olioli" Construction debris should not be C-yathea spp., atnd the "filimoto" or dumped over the steep slopes adjacent to Flacourtia rukam. the dam wdl. Spoil debris should be placed in a designated spoils area. Ideally, The aquatic fauna in the reservoir the previous spoils sites used during the included a number of insect species. The dam construction should be opened up undergrowth contained a diverse for the augmentation project, but closed community of arthropods including ants and revegetated after completion of and gecko (Iepidodactylus lugubris). The constnrction work. grass skink Cryptoblepharus boutonii, was 4.1.4 ForestClearance noted amongst the thick undergrowth. The only bird seen during the field srudy Funher forest clearance of the almost was the Pacific blue duck,4nas complercly inundated Punataemo'o superciliosa but there may be others swamp forest is ineviuble. An area of which v/ere not detecrcd. Most of the approximately 19.2 hectares should be flora and fauna though, identified in the cleared of all vegetation. If clearing is not Vaugh 1991 report, have disappeared done, then as the reservoir fills to its from the fringes of the Afulilo basin. maximum capacity, the vegetation left in the basin will die. As vegetation rots the From a biological perspective, raising the action of bacteria will rapidly use up the dam will not have a significant effect on oxygen in the water. Anaerobic the collection of flora and fauna. The decomposition which is very slow, will area is already disturbed, the vegetation is take over in the absence of orygen and mainly secondary regrowth consisting of Benerate the gases methane and hydrogen common shrubs and herbaceous plants sulphide. The water qualiry results taken and the common tree species identified during this study, four years after Afulilo above. basin was filled up, indicate anaerobic activity is still strong. Before the new 4.1.3 Construction phase maximum capacity level is filled up with The recommended construction option water, all vegetation should be removed is to raise the spillway weir by and placed in an appropriate waste area constructing a 1.7 metres high reinforced above the SL 3L9.2 metres contour level. concrete crest over the existing weir. The This will ensure less anaerobic main advantage of installing a fixed raised decomposition takes place once Afulilo is crest is that there are no significant filled up to maximum capacity. It will operating and maintenance costs also help quickly improve the water involved. quality in the Afulilo basin.
4.2 Effect of the East Diversion Canal
The East Canal would divert run-off 4.2.1 Construction from the northern slopes of range The proposed canal is m be 7,374 metres extending east from Mt Savai'i. The long with a base width of one metre. An proposed canal as seen in Figure 3, will access road will be cut to help lay the intercept several prominent surface sub-base material for the channel. The strearns and from Mt Tiatda Mt canal will be unlined with side slope of 1 Olomaunga ridge and could produce an in 2, for steep areas the channel will be estimated 35 percent increase in yield for lined with the side slope of 1 in 1. Canal Afulilo storag,e. Augmmtation Project of the Afalilo Hydro Pawer Scbeme and road protection will be provided at and children, have to walk some distance creek crossings. to carry water in buckets from the main creek or do laundry washing. During the The routes of the proposed diversion dry season only one stream receives canals are covered in dense re-growth running water from a spring close to the vegetation and the construction of the road. If the diversion canal taps into the diversion cands should only cause source of this spring, then the only temporary disturbance to this dense flowing stream during the dry season may upland forest cover. Good construction dry tp. Women and chil&en will be practices should be utilised to minimise forced ta c rry bucket loads of warcr from soil erosion and sedimentation. Clearing as far a'way as Tiavea proper, one of vegetation should be to the minimum kilometre down the road. required for laying the channel and access road. All disturbed areas which will not be Most farm lands are at the back of the required must be revegetated. village towards the foot of the hills. Some crops may be affected by the 4.2.2 Social effects seasonal changed water volume flovr. Farmers may The proposed canal will run dong the be forced to move their crops close to the foot of the eastern hills and ridge at the hillsides or on the hillsides, but the effect back of Tiavea (Alafou) village' The area is on farmers would be that they now have on customary land that belong m Tiavea to walk long dismnces to service and villagen. The EPC should begin harvest their plantations. Farming up the proceedings to obtain consent from the hillsides will not be beneficial to the villagers for the proposed landuse. EPC Afulilo project. Any disrurbance to the should explain the likely effecm the hillsides will cause soil erosion and landuse proposal will have on the village sedimentation downstream and when to solicit a compromise that would be of diverted to the reservoir will in rurn mutual benefit. reduce the qudiry of water in the Afulilo The proposal will in effect drain off most dam and at the Ta'elefaga taibace. from the surface drainage and streams 4.2.3 Flora and Fauna eastern hills, away from Tiavea (Alafou) village below, to the Afulilo catchment The actual cadastral survey for the been marked out and basin in the west. Most village farms diversion canal has not therefore, a biological survey on are at the back of the village tovrards the yet and foot of the hills. Once the canals are in the actual route the canal would take was However, a general place most of surface drainage during the not undenaken. area the canal route rains (apprcximately 35 percent) will be survey of the of diverted away from the farmlands. showed much of the land is covered with floral cover Altering the surface flow regime will not secondary regrowth of similar the perimeter of only affect plantations, forests, swamPs, as generally found along streams and pools, terrestrid and fresh the Afulilo basin. water animals, but it will also affect the village communities of Tiavea especially, The is an abundance of fresh water fauna the new expanded settlement at Alafou. in the streams and pools found in the area. Eels, shrimps and prawns are found in The community of Alafou expanded out most strearns but are more abundant in of Tiavea once the Richardson road was the one stream that is also fed by a spring. opened. There is no reticularcd water Changes in the warcr flow regime either sysrcm in the village so there is complete through sedimentation from the hillsides dependence of surface water flow from or through reduced water flo.nr could streams and creeks for domestic use. Most adversely affect fresh water fauna in this households rely on three creeks for water area, causing a loss of resources to the supply. Most villagers, especially women Alafou community. ZI
4.3 Increased freshwater outflow into Fagaloa Bay
4.3.1 Tailrace outfall to stream bridge to prevent children falling inro the The natural catchment of Fagaloa Bay is stream, about 14 square kilometres and the Afulilo scheme diverted an additional 12 4.3,2 Discharge fo sea square kilometres into the ban The effect of discharging a relatively approximately doubling rhe freshwater constant flow of lp b 2.6 cubic merres inflow. The proposed augmenration per second of doubtful quality freshwarer project will increase the yield of the into the head of Fagaloa Bay is difficult Afulilo reservoir by about 50 percent to assess. However, it is noted that most, (from 10 million cubic metres to 15 if not all, elements tested previously for million cubic merres srorage capaciry). water quality measurements would sdll This will result in an increase of be present in the new flow regime and approximately 20 percenr of the are considered below. freshwater flowing into Fagaloa Bay. Hydrogen sulphide originating from The Afulilo hydro poq/er scheme is rotting vegetation in rhe reservoir may be currently discharging through rwo released by aeration of the flow in the tailrace pipes, a relatively constant flow discharge creek, and should break down of up to 1.7 cubic merres per second of before the dischaqge reaches the sea. The freshwater into the Ta'elefaga stream and smell factor together with turbidity Fagaloa Bay. The augmentarion project clouding the warer have made the will put in place a third tailrace pipe discharge undesirable since the which when in operarion, rhe combined commissioning of the scheme and will outfall flow would increase up to 2.6 continue to do so for a few more years cubic metres per second. The average after the augmentation project. The annual flood for this stream is 15 cubic tailrace discharge is more acidic (lower metres per second. Therefore, it is pH) than normal srream warcr but this is considered that an increase in the tailrace not a concern as the buffering capacity of outflow will not cause significant saltwater will neutralise any acidity environmental impacts since the immediately on mixing. Concenrrarions increased flow would be within the of dissolved iron and manganese, natural variabiliry of the current inflows although currently very low, may into Ta'elefaga. increase over time with more surface area of Afulilo basin under water, but these Vith the current flow rare, the stream will precipitate our as floc when the level is more than three-quaners the tailrace discharge is re-orygenated during height of the bridge. Villages have the flow downsrream ro the bay. The floc indicated that during the rainy season the will fill spaces in and around srones, but bridge is often over flowed, rhe warer otherwise are reladvely harmless. flowing over the bridge at times make crossing the bridge dangerous. The likely The only possible issues are therefore, the effect of an increase in constant flow to effects of lowered salinity due to the 2.6 cubic merres per second would make addition of freshwater, and sediment crossing the bridge dangerous and limit suspended in the discharge. These two access to either side of the village. A new issues warrant further study to determine bridge should be built before the accuracy of the claim by Ta'elefaga commissioning of augmenration project. villagers, thar the discharge into the bay The bridge should be raised higher than not only affects the water qualiry but it the current one and should have safetv affects as well, the communal use of the screen rails alongside both sides of the bay and che fisheries resources therein. 22 Augmmtation Projeu of the Afulilo Hydro Power Scheme
4.4 Additional noise at Taelefaga Power Station
Hydro-power stations are not normally area. The following formula was used to noisy. The current noise levels with two arrive at the new noise level: use range from 48 dBA at the turbines in Soundl : xdecibels fale at night to 92 dBA inside the plant. SoundZ - ydecibels Each of the rurbines produce an average Total sound : Sr noise output of 85 dBA measurement inside the plant. Vith the proposed 107'o bels installation of the third machine at ST log,o(10/'o+, ),in Ta'elefaga, one of the concerns that need or S, lo log,o(10/'o 1 19/ro) decibels to be addressed is noise level in the Control in Industry surrounding village, particularly the Source: Adapted from Noise Sound Research Laboratories addition of a school across the road. The E. and F.N. Spon, London. third rurbine machine would onlY increase the total noise level to The additional noise level expected from approximately 95 dBA at the machine the augmentation project is considered negligible. Nevertheless, the practice of keeping all doors closed during night time operations should be strictly maintained.
4.5 lnstallation of additional Diesel Generator at Tanugamanono Power Station
The project involves the installation of a should have a more efficient noise new 4M\( diesel generator to helP emission level than the old diesel maintain diesel generating capaciry that machines currently in use. The new together with hydropower, will enhance machine would have a lower noise level capability to cater for the energy supply than the current noise output and demand of Upolu electricity users. The therefore, based on the logarithms benefit from this new installation will be calculations used in Section 4.4, it is the improved security for generating unlikely that the new machine in power system stabiliry and for use during combination with older machines will the periods of maximum system demand' produce noise pollution at levels higher than the current high of 103 dBA at the The main environmental (including generating area. social) effects of diesel generation at Tanugamanono have been highlighted in the earlier chapter. It is considered that Figure 5 (opposite) shows acceptable the addition of a new diesel generetor to noise reduction levels at various sites or the power station will not add further acdviry areas. The concern therefore, is significant impacts to the already that the current high noise levels from unacceptable situation of diesel Tanugamanono should be reduced generation at Tanugamanono. The immediately to achieve, as near as additional4M\f engine, being new, 2J possible, the above reduction level shown generation capacity where there will be in Figure 5. very little night time diesel generation and the use of only one diesel generator It is assumed that the new generator will during daytime operations. Thus, the raise the consumption of diesel fuel and introduction of another generator at this oil, additional water for cooling, bur also stage is not an environmental concern. would contribute to an increase in \$(rhat is important is that urgent exhaust fumes and waste oil and warer. measures should now be taken to However, once the Afulilo augmentation improve the exhaust and noise pollution, project is completed, there will be more reactivate and improve the waste oil and hydropower capacity available and less water disposal system and improve the diesel generation may be used. EPC may cooling water supply system at soon achieve an efficient power Tanugamanono power station.
Figure 5: Noise reduction outside power station building
Encmr '96 Aagmentation Pmject of the Afalilo Hydm Poater Scheme 24 5 CONCLUSIONS AND RECOMMENDATIONS
This report examines the likely (1) The raising of the Afulilo dam will environmental impacts the augmentation increase the ponding area from 250 phase of the Afulilo hydro power scheme hectares to 770.4 hechres. The extra will have on the natural and social 19.4 hectares that will be flooded environments of the project area. The with water should be cleared of all study makes extensive use of material standing vegetation. Such clearing is reported in the environmental impact necessary, both to protect the quality of water in the reservoir, and for rhe assessment @IA) report prepared by \7augh et al. in 1997.lt reviews that work operation of the dam. The felled trees and advances further conclusions based should be removed away from the on new information acquired through new pondingarea and cattle farming this current study. should be relocated.
(2) The 1991 EIA report has highlighted the During dry years, the Afulilo lake vdue of comprehensive environmental level will fall and there will be larye impact assessment of major projects and areas of rocting vegetetion on exposed its effectiveness in enhancing areas. This may cause bad smells and environmentally sound decision-making. foul the water. The report recommended against a diversion canal option from Vaipu basin (3) The Department of Agriculrure, because the country would lose "the only Forestry and Fisheries (DAF$ is significant montane wetland of its type in looking into using the reservoir for Samoao. The 1991 EIA report provided Tilapia farming. The currenr warer additional information of the project to quality measurements indicate the successfully influence the decision- possibility of the reservoir supporring makers to abandon the proposed drainage marine life. canal from Vaipu basin. \7here the 1991 report has provided insufficient coverage It is recommended that exotic fish is of issues, this report has broadened its not introduced inm the Afulilo or andysis to all tractable issues and Vaipu basins. DAFF and DEC must combined the treatment of these first undertake an environmental throughout the Afulilo Augmentation impact assessment of Tilapia farming Project Report. in Afulilo basin to derermine the need for this activiry and rhe likely effects This section sets out the principal the introduction of the exotic findings and recommendations of the species will have on the aqru tic/ report. The recommendations are marine life in both Afulilo and Vaipu addressed to the Government of Samoa basins. which requested this report well in (4) advance, and during the planning stage of Raising of the dam cresr will require the Aftrlilo augmentation project. smdl construction work, but it will lead to exposed areas of soil and spoil, 2t
and rubbish. EPC should reopen rhe avoid overflowing during flood old spoils area to be used for this periods and should have safery rails work. EPC should require from alongside both sides to prevent contracrors that spoils and rubbish accidental falls by children. are not dumped over rhe dam wdl, and that all exposed soil and spoil (7) It is obvious to Ta'elefaga villagers areas are revegetated at the that the current flow regime into completion of the job. Fagaloa Bay has caused the disappearance of some marine species (5) The two generarors for the power which provide an important parr of scheme at Ta'elefaga village have been subsistence living for the villagers. producing acceptable noise levels. The new flow regime will have The introduction of a rhird generator significant long-term effects and it is will not raise the noise level any therefore recommended that a general higher. In fact the combined noise mapping of the marine communities level of the two machines will drown at Fagaloa Bay be undertaken before the noise from the third machine. It the augmentation project is is expected that the new noise level at commissioned. This baseline srudy evenings, will be around 48 dBA at should also design a monitoring the boundary of the nearesr house in progrunme to observe and record the village. This is within the New changes. It is also recommended that Zealand noise standard for EPC conduct public consultadon continuous noise emission at nighr meetings with the villagen explaining the augmentation project, the likely Ic is recommended that EPC enforce effects and the actions/studies rhat its operation procedure at Ta'elefaga will be undertaken to mitigate the station to keep the sliding door closed likely impacts. during night time operations. In the absence of its own regulation, Samoa (8) The construction of the easrern should adopt the noise standard of diversion cand will drain surface around 48 dBA at the boundary of a water from the mountain and ridge at home for continuous noise emission the back of Tiavea village away from at night. the village and into Afulilo basin. Tiavea's main water supply is from (5) The tailrace water from rhe three streamsr f,wo of them dry ,rp powerhouse will be discharged into during dry periods. the stream which flows through the village and into Fagaloa Bay. The new It is recommended rhar a warer flow level of 2.6 cubic metres per reticulation system for Tiavea second will be substantially more villagers be consrructed first before than the current flow of 1.7 cubic the canal construction. metres per second. The water will continue m be discoloured and have (9) Canal constnrction will involve an unpleasant smell for two to three movement of trucks and construction years after the commissioning of the personnel to lay the canal and build augmentation project. access road. Construction work will lead to exposed areas of soil and spoil It is recommended that a new bridge which should be revegetated after is built prior to the commencement compledon of the job. Land clearance of the augmenration project. The should be to the minimum required bridge should be built high enough to for the canal lrying and the access Augmenution fuoject of the Afulilo Hydro Pnt)er Scheme 26
road. All constnrction rubbish should to an environmental impact be placed in a designated spoils area, assessment. In the meantime, the closed and revegetated after use. current situation of the power station should be improved. EPC will need to discuss the project with Tiavea villages to obtain It is recommended that the permission to build the canal on unacceptable noise level be reduced Tiavea land. EPC should monitor the by EPC purchasing a new noise work of the contractors on the canal reduction devise, a silencer with an to ensure the drainage canals do not efficiency to reduce the noise level to drain all surface water flows away around 45 dBA at the nearest house. from the streams supplying the The exhaust fumes stack should be village. extended higher to ensure exhaust fumes do not flow directly into the (10)It has been determined in the Afulilo upstairs rooms of the nearby houses augmentation and inception rePort but are dispersed at a much higher that the Tanugamanono diesel Power level. The waste oil and water station is becoming a non-viable collection and disposal system should operation and has recommended be reactivated. This system is in place relocation. Relocation may be a long but has not been operated efficiently. term plan but it must be subject first
REFERENCES
Bell, L.A.J. and Matsunaga. Y. 1996- HECEC. 7997 . Institational Strengthming Potential of Afulilo Reserttoir for Fish & Puper Deoeloprnent of tbe Electric Power Stoching. Ministry of Agriculture, Forestry Corporation, W'estern Samoa. Corporate tVestern and Fisheries, Apia, Samoa. Srrengrbening. Droft Final Report'Volurrte 3. Hydrrr Electric Commission Enterprises Carpenter, R.A. and Maragos, 1989. J.E. Corporation, Australia. Haw to Assess Enttirontnental Impacts on '\tr(/augh, Tropical Islands and Coastal Areas. J., Lawless, P. and Chadderton, L. Environment and Policy Institute, East- 1991. Afulilo Hydroelectric Pmoer Project 'West Center, Honolulu, Hawaii, USA. Enaironmental Impact A ssessment. South Pacific Regional Environment Programme HECEC. 199 6. Draft Afulilo Augmenation (SPREP), Apia,'$0estern Samoa' and Project Inception Report T4 No' 2267' SAM. Hydro Electric Commission Vhistler,lilf.A. 1995. V(ayside Plants of the Enterprises Corporation, Australia. klands, A Gui"de to the lnttland Flora of the Pacific Islands. Isle Botanica, Flonolulu, 1997 . Institutional Strengthening HECEC. Hawaii 96826. and Power Deaeloprnent of the Electric Pswer Corporation, W'estern Samoa, Corporate Zann, L.P. lg92 Review of Introductions of Strengthening. Drdft Final REort'Volume Aquatic Species into W'estem Samoa and an 2. Hydro Electric Commission Enterprises Assessment of their Environmental lrnpacts. Corporation, Australia. Food and Agriculture Organization of the United Nations, Rome, Italy. Annexes 28 Ausmmtation Proiect of the Afulilo Hydro Pauer Scheme
Augmentdtion Projea of the Afnlilo Hydro puwer Scheme 32
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The source is dead. The Afulilo project has drastically affecrcd rhe Ta'elefaga stream and catchment. (vii) Fisheries Resources
Fagaloa Bay : any observed changes since 1993?
type of fish - atule (iatali). Theres no more atule but there was a lot before rhe Power house was built. According to the villagers the following shellfish are nor found anymore: alili, tugane, fole, gau, fatuaua, tuitui
any reef? Yes.
Brr-hi"g fn rh9 Bayl Not a popular place for bathing as rhe water is very dirty and smelly. (skin infection) Not clear.
(viii) How reliable is the tap water supply for drinking/bathing/ washing?
Not very good in sunny season.
(ix) A pond was supposed to be excavated above the tailrace for the villagers' use. Has this been done and how usefut is it? This hasn't been done.
(x) Any other observations/comments to add? Vhen the river flooded, there's a lot of sedimentation and mud in the bav and this spreads out on the beaches on both sides of rhe river. They said thaithe depth of the mud is about one foot when the river is flooded. it also gives a very bad smell and it can go for two months. One said that smell is worsr ihan the smell of rhe septic tank.
One Matai said that the EPC was supposed to build six feet concrete banks on both sides of the river as a p^fi. of the conrracr but this hasn'r been done.
The following Matais were present on behalf of the villagers of Taeleafaga.
Gago Masani Fuiava (village mayor) kuta Sialafau Sua Ofisa Fuivailili Saitu Sua Airupe Sinamaitai Apete Sanerivi.
The village meeting was conducted by Mr Petelo Ioane on behalf of the assessors. Augnentation Project af the Afulilo Hydro Pawer Scheme 30
ANNEX 2
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