Philippines - Water Districts Development Project : environmental assessment summary (Vol. 2 of 5)

oL. 2 Republic of the Philippines Local Water Utilities Administration SEWERAGE AND SANITATION PROJECT WATER DISTRICT DEVELOPMENT PROJECT WORLD BANk ENVIRONMENTAL ASSESSMENT lLoN REPORT DAVAO CITW Yp SA AS _f 9 2_ ~DAVAO CITY 9wJINDAM ANXIOM ,9 March, 1997  . p I  DAVAO ENVIRONMENTAL ASSESSMENT REPORT ERRATA: page 38, first paragraph: "Several potential sites... Planning Department (see Figure 3." page 38, first paragraph of B. Toril: "Two sites have been identified (see Figure 3.2 by the City...." page 58, first paragraph: "To evaluate the overall... district in Table 4.5 CDM (1994).... page 59, first paragraph somewhere past midway: Table 4.5 shows that a conservative.... page 61, second paragraph, 2nd sentence: The coliform counts reported in Table 2.6...  rt  * * 'iO..eA wB- SCAIINNED Republic of the Philippines Local Water Utilities Administration SEWERAGE AND SANITATION PROJECT WATER DISTRICT DEVELOPMENT PROJECT WORLD BANK ENVIRONMENTAL ASSESSMENT UfON REPORT b g DAVAO CITY DAVAO March, 1997  f 4f  TABLE OF CONTENTS P_ge EXECUTIVE SUMMARY I Chapter I INTRODUCTION 12 Chapter 2 BASELINE ENVIRONMENT - DAVAO CITY 16 Section I Existing Environment 16 Section II Environmental Pollution 21 Chapter 3 PROJECT DESCRIPTMON AND ANALYSIS OF ALTERNATIVES 30 Section I Project Rationale and Objectives 30 Section II Sanitation 30 Section m Overall Sewerage Scheme 32 Section IV Recommended Project Design for Davao City 49 Section V No Project Scenario 53 Chapter 4 ENVRONMENTAL IMPACTS 54 Section I Beneficial Impacts of the Project 54 Section II Project Iinplementation Impacts 63 Section m Summary 66 Chapter 5 ENVIRONMENTAL MANAGEMENT PLAN 67 Section I Mitigation Plan 67 Section II Monitoring Plan 69 Section III Implementation Arrangements 69 Appendices I. Bibliography 2. Climatological Normals (1961-1995) 3. Typical Noise Emissions of Construction Equipment 4. Expected Noise Levels at Various Distances from Construction Equipment 5. Environmental Quality Standards For Noise Maximum Allowable Noise Levels 6. The Advanced Integrated Pond System (AIPS) of Wastewater Treatment Environmental Assessment Report: Davao Citv  i I I? I  EXECUTIVE SUMMARY Introduction In the Philippines, the typical urban area/built-up area is characterized by a heavy concentration of activiies, both commecial and industrial. It is also the area where the density of population is at its peak. These areas are also the sites where the production and consunption of raw and processed materials could be found. Consequetly the, pressure on the life support systems in these areas are far higher than the suburban and nual areas. Advese environental conditons such as the generation and similarly the discharge of wastes into the environment is common in urban and built-up areas Unfortunately, the an, type and concenrion of waste gencrated exceed the capability of the local environent to absorb and assinilaethem. The cariymg capacity ofthe life support systems are stretched to the limits. The urgn of estabhlishing collection and tment methods which will preven adverse impacts to thc health and well-being of the residents, and to the ecological systems which sustain them cannot be ignored and overstated. Most urban centers in the Philippines rely on individual septic tank systems for the treatment and disposal of wastewater from domestic and commercial buildings. However, the designs for such systems is often inadequate. Facilities for land disposal of effluents from the septic tanks are generally absent. Hence the partialy treated septic tank effluents flow directly into storm drainage systems and other receiving bodies of water, thereby exacerbating an already grave poilution situation. There are several possible options for addressing this problem, including improving the design of the septic tank system with the installation of soil absorption systems. But an environmentally sound alternative that is cost-effective and captures economies of scale is to connect individual properties directly to a sewerage system for the collection, treatment and disposal of the urban wastes. The provision of a cost-effective centralized wastewater collection, treatment, and disposal is the pnmary objective of the proposed Water DisicU Dewiopmnent Poject. The proposed project will assist the local governments of Dagupan, Calamba, Laguna, Cagayan de Oro, Davao City and Cotabato City, in finding solutions to the problern of sanitaLon. Better sanitary conditions will thus be experienced in the areas served by the sewerage, drainage and sanitation systems. This will reduce water-borne pollution and water-logging within the cities and in the surrounding water bodies, thereby bringing health benefits to local populations. In Davao, Cagayan de Oro and Calamba cities, pollution from human wastes have affected recreational areas, such as beaches and lake front areas. Project Environmental Assessment Report: Davao CitY I  investments in wastewater collection and treatment will also have positive benefits in terms of improving prospects of saving the remaining beaches for the city residents. The construction of the systems will protect shallow groundwater aquifers from contarnination, particularly in Toril area of Davao city, which forms the source of the city's water supply system. Environmental Assessment Requirements This Environment Impact Assesmen Report for Davao City has been prepared in accordance with the P*eldental Decree No 1586 otherwise known as the Environmentl Impact Assessment Law and Department of Environment and Natural Resources Revised AMsinimaiw Order Nos 36, the Rvised Water Usage and Clsszficataon/Water Quality Cnteria and RevisedEffluent Regulmions of 1990 rqsevely, and WorldBank 's OperationalDirectie 4.01 on EnviromnentalAuesment. The revised Administrative Order 36 for Environmental Impact Statement System issued in 1996 is comprehensive and is compatible with the World Bank's Operational Directive 4.01. It outlines the procedure to be followed by environmental critical proiects (ECP) and project to be located in environmental critical areas (ECA) in preparing enviromnental impacts statement (EIS) . ECP and ECA are defined in the AO It should also be noted that that local ordnances and regulations goveng projects of such nature have been taken into consideration in preparing tis report. Similar EIA reports are beng prepared for the other 4 cities. This report has been prepared by a team of local conslants under the aegis ofthe Local Water Utilities Adnwstration (LWUA) and the Davao City Governent Much of the work relaing to the envionmental impact analys was undertaken as part of the feasibility study done by C. Lotti and Associati. Consultation with the community is an on-going process. The sanitation component of the project will be exeated in a participatory manmer, and detailed guidelines have been speled out. Selection of Priority Cities The choice of the first batch of Philippine cities for sewerage investments was made after an initial screening at the national level of urban areas facing the most serious problem of pollution by untreated wastes. Of the five cities, Davao and Cagayan de Oro represent the largest class of provincial cities with current population estimates in the range of a million and half a million respectively. There are several major population concentrations in the city; each being a source of sewage contamination for nearby surface and ground water. However, the largest volume of sewage is generated by the largest consumers of piped water supply; in the Central Business District or Poblacion area. Untreated wastewater from this area has polluted low-lying coastal areas, and basically converted the principal rivers into open sewers.. The scale of the pollution problem can be appreciated by the fact that about 90 per cent of the daily water supply of 140,000 cubic meters in Davao city and Tius is the term used by DENR and refers to the standard Environmcntal Assessment Report required by the World bank as per OD 4.01 Environmental Assessment Report: Davao Citv 2  76,000 cubic meters in Cagayan de Oro is being discharged as untreated wastewater. Outside the Poblacion areas, there are pockets of population concentrations polluting nearby streams, creeks and channels. In the other three cities of medium size (Cotabato city, Calamba and Dagupan), current population estimates are close to 200,000. While the scale of urban pollution problems are not comparable with Davao and Cagayan de Oro, these cities are located close to environmentally sensitive wetlands and water bodies. In Cotabato city, the urban area is actually below the mean sea level, exposing inhabitants to frequent waterlogging during the monsoon months. Calamba is located on the shores of Laguna Lake, which has experienced a rapid deterioration in water quality over the last two decades. Dagupan city is close to a large estuarine zone with ecologically sensitive wetlands and fishponds. In each of these cities, Mayors and city officials have recognized for some time that unless their complex environmental problems are tackled through a strategic plan of handling waste disposal, sustainabiity of urban growth could be seriously affected. Overall Project Approach The proposed project follows a demand-based approach, in the sense that facilities will be constructed only if they conform with the preferences of local stakeholders, and services conform to their respective willingness to pay. The stakeholders represent the different tiers of organizations from the City Council and Barangay (part of the formal LGU system), to the more informal purok, neighborhood and household levels. During project preparation, the idea of involving communities in the planning process was field-tested in three barangays of Davao city, and found to be quite successfil. The basic decision- making process is as follows: For the capital-intensive trunk system, consisting of the main transportation sewers, primary drains and wastewater treatment facilities, the project design and implemnentation plan has to be approved by the City Council, because the latter is responsible to repay the loan [see Annex 3 on Fmancial Aspects, Staff Appraisal Report (SAR)]. For the feeder system, consisting uf collector sewers, secondary drains and on-site sanitation facilities, barangays and local neighborhoods will be associated with the planning and implementation program. The design criteria have been simplified, so that the feeder system can respond to local preferences and willingness to pay, rather than be bound by any conventional sewer design criteria used in industrialized countries. Detailed design will be conducted through a participatory process described in Annex 13, SAR_ Given the capital-intensive nature of the investments, the proposed project is only the initial phase of a program to improve the sanitation infrastructure through a strategic planning approach that involves a mix of on-site and off-site wastewater collection, treatment and disposal. Choice of initial service areas for sewerage has been confined to the Central Business Districts or Poblacion areas because these are the major contributors Environmental Assessment Report: Davao Citv 3  to municipal wastewater pollution. The only exception made is in the case of Davao City, where a second area of high growth prospects (TorI) has also been included on the request of the LGU. The project will construct a sewer network that will discharge sewage to a vertically integrated pond system designed to treat both sewage and septage. In each of the cities, with the exception of Davao, the treatment site was selected in areas free from encumbrances. For the sanitation and drainage components, the entire city has been included in the project area, with final selections being made on the basis of demand. On-site treatment systems through the construction of VIP latrines, pit latrines, pour flush toilets and septic tanks will also be constructed if there is demand from property owners. For those properties with uncertain land tenure (as in squatter settlernents), the project will finance the construction of communal toilets, to be managed by NGOs and/or the private sector. The specific location of these facilities will be driven by the willingness to pay for the services by beneficiaries at the barangay leveL provided of course that these are technically feasible. Analysis of Alternatives The recommended solutions for wastewater treatment were arrived at after an intensive process of evaluating alternatives during the project preparation in order to achieve cost effectiveness and acceptability. The alternatives considered were anaerobic/facultative Ponds, modified lagoon systems and mechanical treatment. The evaluation of alternatives indicated that the modified lagoon systems, despite having a higher O&M costs compared to anaerobic/facultative ponds (as it requires mechanical aerators and recirculation pumps) was appropriate. The selected option met the foliowing criteria the effectively: irnimize overall pond area required Minimize odor production Meet DENR effluent quality criteria, including fecal coliform reduction Minimize sludge production rate Maximize potential to use surrounding land for recreational purposes Environmerral Assessment Report: Davao Cirv 4  Summary Information on Project Cities Davao Cagaan de Or o Cal D Poqulation(1990) 849.947 339,598 127.065 173.453 12S.ooo Housnng 163329 47.724 21.5S1 32109 21.219 Sizeof'CIaa 1000 l eOOOh 400hbecaa 120bc 95bets 50bedae B _S~Diarc (CBD) Morbiditv rae per 95 for 733 for diarrhta 3050 for diith 3l 2 for puastim 523 for pgi- 10.000 f diseam diuXagturd (tird re*) (rtun ran) (second ra*) enteritis (thd Ta-k ar" rank) diseases) Wer bodies at risk DSaW nu ad Csapr nvrad About 50% of cty Laguna Lake About 50% of cIty becane of _cul a8 bead. claw adjondug beace a us- of am am wdilmds. poihg to city no it for on Mpajlsw Bay wdand fib ma l usd for fish rea_ahal udit for pondse ad midity sidid farusug P,_mpo bmmo(feesI _ _ ~~~~~~~~~~~~~~~~onnm tof n The urban area/built-up area in the project cities is characterized by a heavy concentration of commercial and industial activities. It is the area where population density is highest. These areas are also represent the bulk of economic activity in the informal sector - such as, the production and consumption of raw and processed food, light manufacturing activities and retail distribution. A large proportion of piped water supply from the local Water District is also consumed in the Central Business District. Consequently, the pressure from both solid and liquid wastes in these areas greatly exceed the capability of the land and water resources to absorb, assimiate and recycle them. Davao City Impact Dunng Construction Phase The implementation of the project and-its components is projected to produce only minimal adverse environmental impacts. The socio-economic impacts will be beneficiaL and will result in a better standard of living for the municipalities and cities concerned. In the short-term the project will provide emnployment and livelihood opportunities to the population of the surrounding communities through the jobs generated during the construction phase. In the long-term, better sanitary conditions will reduce sicknesses caused by water-related problems. Thus an improvement of the existing environmental conditions is expected. The project will undertake mitigating measures to minimize, or if at all possible, eliminate adverse impacts. Air Quality. The implementation of the project will result in an increase in the ambient concentration of suspended particulates in the vicinity of the project site. This would be Environmental/Assessment Report: Davao Cirv 5  attributed to dust from land clearing and excavation activities, which expose soil to wind and vehicular traffic over unpaved road. Water Quality. Excavation activities in the project sites could also loosen soils and transport of these materials to any surface waters, thereby increasing siltation and turbidity. During the rainy season, surface runoff may increase total suspended solids, and cause temporary stress at the discharge points. However, the impact will be locaiized, and when the vegetative cover returns, impact on the receiving body of water caused by surface run- off will be eliminated. Noise. The noise irnpact during the construction stage is expected to be generally minimal and will not require any special noise abatement measure. The treatment plant sites shall have a setback away from residential clusters, which will definitely provide the necessary' buffer to reduce noise impact during construction of the modified lagoon systems. During the pipe-laying, some noise will be generated due to the construction activities and the temporary operation of heavy equipment. Noise from breaking concrete pavement and sidewalks may also pose a temporary problem. However, the noise level at the streets is expected to be within the ambient noise quality standards. Socio-economic. The only potentially adverse impact is likely to be in the Davao sewage treatment site, where approximately 15 squatter structures are located in the vicinity of the treatment plant site. The treatment plant, can, however, be constructed without affecting these structures, and hence no resettlement action plan will be required. The City Governments will be requested at appraisal to indicate how they plan monitoring potentially adverse impacts in the project cities. Ecological Effects. As there are no rare, endernic species of flora and fauna in any of the project area, project implementation has minimal impact on the terrestrial ecc!ogy. Vegetative cover shall be unavoidably cleared during civi works. Impacts During Operation Phase Air Quality. The operation of the wastewater treatment facility will have minimal impact on the air quality of the area. Aside from the occasional odor nuisance, it is not projected to have adverse effect at all. Water Quality. The implementation of the project will be beneficial to the general envi- ronment of participating cities and their environs. Discharging of untreated domestic waste water from the high volume consumers in each city's Central Business Districts into nearby bodies of water would thus be minimized or eliminated. However, operations and maintenance failures may result in occasional discharges. Environmental .4ssessment Report: Davao City 5  Socio-economic. The provision of sanitation facilities in the project cities would undoubtedly benefit the general populace of these areas. The occurrence of epidemic- scale diseases caused by current unsanitary conditions will be reduced. This will result in a more healthy and productive population. Sludge Disposal. The modified lagoon system or Advanced Improved Ponds System (AIPS) will require sludge disposal at very infrequent intervals. The sludge in the anaerobic pond/s remains for an extended period continuously undergoing organic decomposition. This may take place over a 20-30 year period. One system in operation in the U.S. has not been desludged in thirty years. Recent testing of this system has indicated that the sludge is well-digested and very stable. If desludging does become due, arrangemnents can easily be made with the city environment office for disposal at the sanitary landfill. Mitigating measures to mininize, or if possible, eliminate adverse impact will be implemented. Measures to enhance the existing environmental conditions in the project site shall be implemented to maintain the enviromnental sustainability of the area. The implementation of the project wilL inevitably produce impact, both adverse and beneficial. Table I shows the potential impact, risks and the proposed mitigating action. Implementation and Monitoring of Management Plan The PMO, with the assistance of LWUA-CPSO and consultants, would monitor compliance with the ECC and carry out the requisite data collection. Monitoring reports would be submitted to DENRIEMB and the World Bank periodically. While responsibility for the various mitigation activities have been identified, the PMO will ensure that the requirements are complied within addition, feedback from comnunities, city officials, NGOs, etc. wiU be pro-actively sought through the city public affairs programs, regular monthly meetings of barangay captains and other methods. Funally, DENR, through its planned PPA system, would also periodically monitor and audit compliance with the ECC, assisted by independent contractors. Table 2 summarizs the responsibilities and timetable for the Mitigation Plan. Environmental Assessment Report: Davao City 7  Table 1: Mitigation Actions Construction Phase Potential Impma & Risks Mitigation Action * Poor qualty of consuon * Design and supevision contra will be separated from supply and installation contract as a means of assuring quality of construcion. Works engineers, with a relatively indepe t source of information on construction progress, will be hired. Air Polluion * Careful consructon planning and work phasiLg, specifications and constrion methods to reduce the length of time that the * Constuction equipment and soil is cxposed to the enviroment vehicles may cause higher * Provision of adequately and propely tainmtad storge for suspended particult, odors and construction materials and equipmn fumes emissions - COt. CO, NO, * Expeditious and prompt removal of cvatd materials or dedged spoils from construction sites. * Exposure of fine-grain particles to * Replar d andequate sprinkling of water on dust-generating wind and vehicular traflic will mnds/piles resulting from eardhnoving activities and civil likely rsult in a decrease in air wrks. quality. * Good housekeepgi for all constructiwo affected as and workpla. * Control of motor vehidcle and equipment ions * Use of protective gear by all workers. Water Polution and Soil Erosion * Provide tempowy dainage and stoage failities for excavtion soils, for fuel and oils needed for equipment * Siltation * Carehfl and rational plnning of construction and post- construction phases of the prcect * Maintesnce of adeae drnagp system. * Noise from operation of construc- * Eect temporay sound barrie around the work sites; avoid tino equipnt woud be about 70- simultaneous use of heavy equipment; limit Jaytime work, 80 dBA at 10 m; 50-70 dBA at 30 vebicle speed at 20 kph; egular maintenac of quipmet m. * Use of apppruiate mufflers and sound proofing of construction machineies, quipment, and engies Use of apprpriate shock- absorbing mountings for mwainy. . Establshment of buffer zones and noie zones * Temporary Dlisruption of Traffic * To the extent possible, feeder and coUecon sewer lins will be Flow located along secondary sbeets * Scheduling and increasing input resources so that period of tmffic disruption in primay roads are reduced. * Coordinate with city tmtEc management office and the PNP Trafic Management Command * Clear diretional signs and barriers in case traffic rerouting is needed. * Public Information campaign. Environmental A.ssessment Report: Davao Citv 8  ________________________ Operation Phase Potntial Impact & Risks MltigaZion Action * Envuroncntal hazards due to * Carefully designed post-construction mantenance, contingencv accidnts and man-made or natural and momtonng programs. disasters. * Well designed plan for detection of accident or natwal events * Breakdown or malfunction of the including precautionary and remedial measures to be sewer lift station will increase level taken/obsavedn of pollution at the mouth of Davao * Adequate plans for environmental rehabilitation, clean-up, River as raw sewage will have to be restoraton, and disposition of temponary strcures and facilities dumped directv. nstIled dng the construition phase. Water Pollution * Upgrade laboratory facilities of the Davao City Water Distnc to be able to undrtake waster analysis. * The effluent dischage point of the * Following the bubble concept, wastewater discharged into Davao treaument plant is affected by tidal River shaL in the lng-tem, conform to the water quality conditions (estuary). sadards established by the Department of Envionment and Natual Resources as set foath in DAO No. 34 and 35, Revised Wate Usage nd Clasification/Water Quality Standards and Revised Effluent Regaltions of 1990, respectivly. * A dispersion/dilution modelig study will be conducted to prior to cating the outall. Treted effluet discharge to Davao River shall be timed based on tidal conditions. The adopton of the AUPS pmcess for the treat plants should result into atainment of effluent stands. * Investiating the possibility of rchbaging the acquifer with urated wastewate fmn Toril teament plant * Noise would be at about 65495 * Establshment of buffer zones and noise zones. dBA, pnncipally coming frotm sptage trucks unloading at the ponds- * Odors (organic and sulfit com- . Maintenance of greenbeit zones and vegetation. poumds mainly from the trucks * Pvison of ladscaped open sscs which wiU impWrove the unloading seWe) aesthtch of the ae by plantiung the gen stnps with approprate plant or tre speci Manasement and O&M of the System Institutional: * Management Conttact with DCWD which has proven utility * Poor maintenance of pumps management and operations capacity. * User consltation at detailed engining d...agn stage to isure * Low connections COODeCtiOn. * Sewerage stcharge should be sufficient to provide inctives for DCWD to maintan system. * Requie M&E repoing to the DENR and LWUA. * Explore feasibility of BOO/BOT contrats for recretional actvities in unused lands at treatmet sites. * Provide adequate training of DCWD and city staff. Retulatory: * Require compulsory connection for all commecial, indusial and high domestic water users. * Utilize Public Perfornance Auditing system being set up by DENR to monitor advere impacts. Technical: * Provision of adequate maintenance eqwupment and spares with DCWD. Environmental Assessment Report: DavaooCity 9  Monitoring and Implementation Arrangements Construction Phase Ambient air quality measurements will be undertaken near construction sites. This will be mostly near locations where sewer network is being laid and treatment plant sites. When selecting sites due consideration will be given to sensitive receptors like schools, hospitals, houses etc. Total suspended particulates (TSP) will be measured once a fortnight, for 8 or 24 hours, over the construction period. Noise wiU measured at the same locations as TSP. Leq and L9o values will be measured and recorded. Overation Phase Receiving water quality will be monitored by the Environmental Management and Protected Areas Service of DENR. The local Regional Technical Directorate agency is currently monitonng the status of Davao river and estuarne water quality on a monthly basis. PMO will collect information on present conditions, observed changes in pollution loads etc. It should be noted that all the pollution load will not be removed and the proposed sewerage infiastucture will greatly reduce the problemn. Once the plan becomes operational, the operator would be required to set-up a laboratory and measure the efflluent quality. Treatment Plant Operator will institute a monitoring program to measure the effluent discharge. Daily representative values of PHK 5-day BOD, COD, Total Nitorgen and Total Phosphorus will be measured during the start-up period. Once the plant operations stabilize, weekly measurements (24-hourly basis) will be taken. Quaterly reports showing the trends of effluent discharge and receiving water quality will be reported to the PMO and DENR Regional Office. Environmental Assessment Report: Davao City 10  Table 2 Summary of Responsibilities and Timetable for the Mitigation Plan Actiw* P-R_PM t Sbu Camp' Sewoe ECC clec fSom DENR. CPSO-LW%'A De.itre 196 mUrdh 1997 CoUsei refe ce amb.a ai poamasi City PMU. wih DENR ional Mwdh 1997 May 1997 dthe Propose nm pit aim at office Pmj cti Enae that the bid doamui imcue PMO Mwrb 1997 Mav 1997 p-v for mnuution ndr the reap-d- lity ofthe comacor re,w coeuataoe work pait to amin co.qgiwAnc with -k virunatal inupon- Pisa -_ _ _ _ _ _ _ Tram opwann on O&M paciem & hw_h% PMO and CPSO-LWUA Deember 1997 April 1998 the Dano City Wer Dwit Dina_ Conduct mi. coemutwicsod udennatn Pn je City PMU. with ance May 197 Deaiher caNVIFg ofNGO. 1997 Monitor and repwt on co_pliance. PMO Bi-anl basis Bial bai LWUAI,vr C:.tIWDDP%SOIC M.W* 19. 19974:224 PM Environmental Assessment Report: Davao Citv 1  I I  1. INTRODUCTION In the Plilippines, the typical urban aea/built-up arm is characteized by a heavy concentration of actives, both conmiercal and industrial. It is also the area where the dnsity of population is at it's peak- These areas are also the sites where the production and consumption of raw and processed materials could be found. Consequently the, pressr on the life support systems in these areas are far hgh than the suburban and nual areas. Adverse eirmnmental conditions such as the generation and similarly the diLharge of wastes into the envirornent is common in urban and built-up areas. Unfortuatey, the amount, type and concention of waste genemed exceed the capabiity ofthe local evronm to absorb and assimilate then. The cariying capacity ofthe life support systems are streched to the limits. The urgency of estabishing colection and treatment methods which will prevent adverse impacts to the health and well-being ofthe residets, and to the ecological systens which sustain them cannot be ignored and ovated. The provision of a cost-efective calized watewater coDection, treament, and disposal is the primary objective of the proposed WacrDi0is DewlopmaU Project. The proposed project will assist the local goverets of Dagupan, Calamba, Laguna, C4gayan de Oro, Davao City and Cotabato City, in finding solutions to the problem of sanitation. Most urban centers in the Philippines rely on individual septic tank systems for the treatment and disposal of wastewater from domestic and commercial buildings. However, the designs for such systems is often inadequate. Facilities for land disposal of effluents from the septic tanks are generally absent. Hence the partially treated septic tank effluents flow directly into stormn drainage systems and other receiving bodies of water, thereby exacerbating an already grave pollution siuation. There are several possible options for addressing this problem, including imnproving the design of the septic tank system with the installation of soil absorption systems. But an environmentally sound alternative that is cost-effective and captures econonies of scale is to connect individual properties directly to a sewerage system for the collection, treatment and disposal of the urban wastes. Better sanitary conditions will thus be experienced in the areas served by the sewerage, drainage and sanitation systems. This will reduce water-bome pollution and water-logging within the cities and in the surrounding water bodies, thereby bringing health benefits to local populations. In Davao, Cagayan de Oro and Calamba cities, pollution from human wastes have affected recreational areas, such as beaches and lake front areas. Project investments in wastewater collection and treatment wi1l also have positive benefits in termns of improving prospects of saving the remaining beaches for the city residents. The Environmental Assessment Report: Davao City 12  construction of the systems will protect shallow groundwater aquifers from contamination, particularly in Toril area of Davao city, which forms the source of the city's water supply system. Overad Approach of the Proposed Project The proposed project follows a demand-based approach, in the sense that facilities will be constructed only if they conform with the preferences of local stakeholders, and services conform to their respective willingness to pay. The stakeholders represent the different tiers of organizations from the City Council and Barangay (part of the formal LGU system), to the more informal purok, neighborhood and household levels. During project preparation, the idea of involving communities in the planning process was field-tested in three barangays of Davao city, and found to be quite successfil. The basic decision- making process is as follows: (a) For the capital-intensive trunk system, consisting of the main transportation sewers, primary drains and wastewater treatment facilities, the project design and implementation plan has to be approved by the City Council, because the latter is responsible to repay the loan (see Annex 3 on Financial Aspects). (b) For the feeder system, consisting of collector sewers, secondary drains and on-site sanitation facilities, barangays and local neighborhoods will be associated with the planning and implementation program. The design critena have been simplified, so that the feeder systenm can respond to local preferences and willingness to pay, rather than be bound by any conventional sewer design critena used in industrialized counties. Detailed design will be conducted through a participatory process. Given the capital-intensive nature of the investments, the proposed project is only the initial phase of a program to improve the sanitation infrastructure through a strategic planning approach that involves a mix of on-site and off-site wastewater collection, treatment and disposal. Choice of initial service areas for sewerage has been confined to the Central Business Districts or Poblacion areas because these are the major contributors to municipal wastewater poliution. The only exception made is in the case of Davao City, where a second area of high growth prospects (Torii) has also been included on the request of the LGU. The project will construct a sewer network that will discharge sewage to a vertically integrated pond system designed to treat both sewage and septage. In each of the cities, with the exception of Davao, the treatment site was selected in areas free from encumbrances. For the sanitation and drainage components, the entire city has been included in the project area, with final selections being made on the basis of demand. On-site treatment Environmental Assessment Report: Davao City 13  systems through the construction of VIP latrines, pit latrines, pour flush toilets and septic tanks will also be constructed if there is demand from property owners. For those properties with uncertain land tenure (as in squatter settlements), the project will finance the construction of communal toilets, to be managed by NGOs and/or the private sector. The specific location of these facilites will be driven by the willingness to pay for the services by beneficiaries at the barangay level, provided of course that these are technically feasible. The reconmnended solutions for wastewater treatment were arrived at after an intensive process of evaluating alternatives during the project preparation in order to achieve cost effectiveness and acceptability. The altemnatives considered were anaerobic/facultative Ponds, modified lagoon systems and mechanical treatment. In all the five cities evaluation of alternatives indicated that the modified lagoon systems, despite having a higher O&M costs compared to anaerobic/facultative ponds (as it requires mechanical aerators and recirculation pumps) was appropriate. Details are available in project files. The selected option met the following criteria the effectively: (a) Minimize overall pond area required (b) Minimize odor production (c) Meet DENR effluent quality criteria, including fecal coliform reduction (d) Minimize sludge production rate (e) Maxize potential to use surrounding land for recreational purposes Environmental Impact Assessment This Environmental Inpact Asmnent Report for Davao City has been prepared in accordance with the PresidentialDecre No. 1586 othewise known as the Env Snenat Impact Assesment Law and Deprtent f bironment and Natol Resoucs Revised Admirnew Order Nos 36, the Revired Water Usage and Clamfication/Water Quabty Criteria and Rev sed Effluent Regulations of 1990 respectivd, and World Bank's Operatonal Directve 4.01 onEfvirnraentAsessmeni. The revised Administrative Order 36 for Environmental Impact Statement System issued in 1996 is comprehensive and is compatible with the World Bank's Operational Directive 4.01. It outlines the procedure to be followed by environmental critical proiects (ECP) and projects to be located in envirornental critical areas (ECA). in preparing environmental impacts statement (EIS)'. ECP and ECA are defined in the AO It should also be noted that that local ordinances and regulations governing projects of such nature have been taken into consideration in preparing this report. Similar EIA reports are being prepared for the other 4 cities. This is the tenn used bv DENR and refers to the standard Environmental Assessment Report required by the World bank as per OD 4.01 Environmental Assessment Report: Davao Citv 14  Ths report has been prepared by a team of local conltants under the aegis of the Local Water Utilities Adminisration (LWUA) and the Davao City Govenunent. Much of the work relaing to the environmental impact analysis was undertaken as part of the feasibility study done by C. Lotti and Associati. Consultation with the community is an on-going process. The sanitation component of the project will be executed in a participatory manner, and detailed guidelines have been spelled outL LWTUAJJa C. IWDDPiCK PJDOC Ac 19, 197 4.26M Environmental Assessment Report: Davao Cty i5  2. BASELINE ENVRIONMENT - DAVAO CITY Introduction This chapter is in two sections. Section I profiles the existing environmental situation in Davao and Section 2 analyses the water pollution impacts (historical) of uncontrolled sewage discharge. Section I - Existing Environment 2.1 Land Reources and Use Davao City, the major development center in Mindanao, is among the highly urbanized cities in Mindanao. The city is situated in the west central portion of Region x) in Southern Mindanao, bounded in the north by the Municipality of Kapalong, Davao Pro- vince; in the northeast by the municipality of Panabo, Davao Province; in the south by the municipality of Sta Cruz, Davao del Sur; in the east by the Davao Gulf, in the west by Mt. Apo and North Cotabato; and in the northwest by the province of Bukidnon. Davao City is approximately 950 kdloneters southeast of Manila It is the largest city in the Philippines in terms of land area (244,000 has.). The city is divided into three congressional districts which is further sub-divided into eleven (11) administrative districts: Poblacion, Talomo, Agdao, Buhangin, Bunawan, Paquibato, Toril Tugbok, Calinan, Baguio, and Marilog for efficient and expedient delivery of basic services. It has a total of 180 barangays. (See Figure 2.1) Table 2.1 shows the Land-Use in Davao City based on aerial photos taken in 1994 and as plotted by the City Planning and Development Office, Davao City. Table 2.2 presents the Urban Land-Use in the city. 2.2 PhvsioMraohv and GeoloRy The topography of the area is relatively flat and rolling. The soil is very rich and fertile as evidenced by the agricultural activities in the area. The area has undergone physiographic changes in recent times with the southern portion expanding due to deposition and the northem portion being eroded. These natural processes were direct results of the action of the Davao River. Environmental Assessment Report: Davao Citv 16  T Canowo C. * /X" ngan~~~~~jnmnI,- TogokpcA a~~~~~ mips .. . -/~No ,uuIgngo ~ ~ ~ ~~ ~~~~~~~~~~~~~~~~~~ancoGlugn SinfOl 7;019 -do" %,~~~~~~~' ~gbnc~ *\'..lManmwbbuIon s VacuA ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ % a vane ~~~~~~~~~~* AIO \:-N~~~~~~~~~~~~~~.~~~4~~~ , Miasma ~~~~~~~ ~ i/ hre\