environmental and social impact assessment of the...

ENVIRONMENTAL AND SOCIAL IMPACT ASSESSMENT OF THE UPPER MARIKINA DAM GREATER METRO MANILA AREA FLOOD MANAGEMENT PROJECT REQUEST FOT PUBLIC SCOPING 14 July 2017

for the

DEPARTMENT OF PUBLIC WORKS AND HIGHWAYS Bonifacio Drive Port Area 652 Zone 068, Manila, 1018 Metro Manila and THE WORLD BANK

Prepared by DOHWA ENGINEERING CO., LTD. Project Consultant for the Feasibility Study and Preparation of Detailed Engineering Design of the Proposed Upper Marikina Dam and CHACHI CIVIL ENGINEERING SERVICES ESIA Subcontractor

REQUEST FOR PUBLIC SCOPING Environmental and Social Impact Assessment

Upper Marikina Dam Greater Metro Manila Area Flood Management Project

TABLE OF CONTENTS |xi

Table of Contents

ABBREVIATIONS AND ACRONYMS ......................................................................................................... xiii REPORT TITLE, AUTHORS AND DISCLAIMER .......................................................................................... xiv PROJECT SUMMARY ...............................................................................................................................xv CHECKLIST OF DOCUMENTS ................................................................................................................. xvii PROOF OF CONDUCT OF IEC ............................................................................................................... xviii RESULT OF THE PERCEPTION SURVEY ................................................................................................... xix PROJECT DESCRIPTION FOR SCOPING .................................................................................................. xxii 1. INTRODUCTION .................................................................................................................................. 1

1.1 Project Background and Rationale ............................................................................................. 1

1.2 ESIA Objectives ........................................................................................................................... 2

2. BASIC PROJECT INFORMATION ........................................................................................................... 3 1.3 Project Information .................................................................................................................... 3

1.4 Proponent Profile ....................................................................................................................... 3

3. PROJECT DESCRIPTION ....................................................................................................................... 5 1.5 Project Location and Area .......................................................................................................... 5

1.5.1 Project Location ............................................................................................................... 5

1.5.2 Area of Influence (AoI)..................................................................................................... 6

1.6 Impact Areas .............................................................................................................................. 7

1.6.1 Direct Impact Area (DIA) .................................................................................................. 7

1.6.2 Indirect Impact Area (IIA) .............................................................................................. 10

1.7 Regional Impact Zone (RIZ) ....................................................................................................... 11

1.8 Project Components List .......................................................................................................... 13

LIST OF FIGURES

Figure 0-1 Artist’s rendering of the Upper Marikina Dam ....................................................................... 1 Figure 0-1 Project Location, Proposed Upper Marikina Dam .................................................................. 6 Figure 0-2 General Layout of Flood Controls dowsnstream of UMD ....................................................... 8 Figure 0-3. UMD Catchment Area ........................................................................................................... 9 Figure 0-4 UMD Location Alternatives.................................................................................................. 10 Figure 0-5 River Basins, Lake Basin, and Drainage Basins in the Greater Metro Manila Area ............... 12 Figure 0-6. The Yokohama Dam - a similar structure to UMD ............................................................... 13 Figure 0-7 Typical Dam Sections ............................................................................................................ 14

LIST OF TABLES

Table 0.1 List of barangays in the catchment area of UMD ................................................................... 10 Table 0.2 Features of River Basins, Drainage Basins and the Laguna Lake Basin ................................... 11



TABLE OF CONTENTS |xii

LIST OF PHOTOS

Photo 0.1 Montalban Gorge .................................................................................................................... 7 Photo 0.2 Visualization of UMD through the Montalban Gorge ............................................................. 7

PROJECT DESCRIPTION FOR SCOPING Environmental and Social Impact Assessment


ABBREVIATIONS AND ACRONYMS |xiii

ABBREVIATIONS AND ACRONYMS

DAO DENR Administrative Order

DED Detailed Engineering Design

DENR Department of Environment and Natural Resources

DFAT Department of Foreign Affairs and Trade

DIA Direct Impact Area

DPWH The Department of Public Works and Highways

ECC Environmental Compliance Certificate

EGF Environmental Guarantee Fund

EIA Environmental Impact Assessment

EIARC Environmental Impact Assessment Review Committee

EIS Environmental Impact Statement

EMB Environmental Management Bureau

EMP Environmental Management Plan

ESIA Environmental and Social Impact Assessment

ESMP Environmental and Social Management Plan

FS Feasibility Study

GDP Gross Domestic Product

GPS Global Positioning System

IEC Information Education Campaign

IIA Indirect Impact Area

IP Indigenous People

IPDP Indigenous People Development Plan

IRR Implementing Rules and Regulations

ISF Informal Settler Families

IUCN International Union for Conservation of Nature

JICA Japan International Cooperation Agency

LGU Local Government Unit

MCM Million Cubic Meter

MGB Mines and Geoscience Bureau

MOA Memorandum of Agreement

NGO Non-Government Organization

NTP Notice to Proceed

NWRB National Water Resources Board

PAGASA Philippine Atmospheric Geophysical and Astronomical Services Administration

PAPs Project Affected Persons/People

PAWB Protected Area and Wildlife Bureau

PD Presidential Decree

PDS Project Description for Scoping

PEISS Philippine Environmental Impact Statement System

PHIVOLCS Philippine Institute of Volcanology and Seismology

PH-PTF Philippines Programmatic Trust Fund

RAP Resettlement Action Plan

RIZ Regional Impact Zone

RPM Revised Procedural Manual

SDF Social Development Framework

SDP Social Development Plan

SVAP Stream Visual Assessment Protocol

TSP Total Suspended Particle

UMD Upper Marikina Dam

UMRBPL Upper Marikina River Basin Protected Landscape

WB World Bank



TITLE | AUTHORS | DISCLAMER |xiv

REPORT TITLE, AUTHORS AND DISCLAIMER

Title REQUEST FOR PUBLIC SCOPING

Environmental and Social Impact Assessment of the Upper Marikina Dam Greater Metro Manila Area Flood Management Project

Beneficiary:

Department of Public Works and Highways Government of the Philippines

Consultants: DOHWA Engineering Co., Ltd.

ESIA Subcontractor: CHACHI Civil Engineering Services

Source of Project Funding: The World Bank

Study Team Members

Louernie F. de Sales, Ph.D. Welesito M. Rombaua, MA Julius F.B. Giron, RCE Joseph P. Lalo, MA Milben A. Bragais, MS Engr. Charlon Gonzales, MS Lorenzo Antonio Lim, RChE Maria Connie Alvior, RChE Chijun Kim, CE

Environmental Specialist and Team Leader Socio-Economic Analyst / Economist Water Quality Specialist/Water Resources Engineer Anthropologist Terrestrial Ecologist (Flora and Fauna) Air Quality Specialist/Climate Change Specialist Pollution Management Officer, EIA Specialist Environmental Specialist Waste Management Specialist

Document Revision Table

Version Number

Date of Issue Author(s) Brief Description of Change(s)

1 11 July 2017 Louernie F. de Sales, PhD and Team

2 20 July 2017 Louernie F. de Sales, PhD and Team

Changing the Document Title from Project Description for Scoping to Request for Public Scoping based o Section 7of the DENR Administrative Order 2017-015.

Disclaimer

The content of this report constitutes technical assistance provided solely for the project purpose and its terms of reference and is the sole responsibility of CHACHI Civil Engineering Services. The views expressed herein cannot be taken to be the opinion of the Department of Public Works and Highways (DPWH) or the World Bank (WB).

The authors welcome further discussion of issues raised in this report.

This report, and other project reports, should not be distributed without the written authorization of DPWH.



PROJECT SUMMARY |xv

PROJECT SUMMARY

Project Title: Environmental and Social Impact Assessment of the Upper Marikina Dam Greater Metro Manila Area Flood Management Project

Overall Project Goal:

Recurrent flooding has the greatest negative impact on the poorest populations who generally live in higher-risk flood prone areas. It restricts people’s ability to exit from poverty and inhibits growth. It causes damage to houses and property and impedes movement and traffic out of the flooded area thereby affecting productive capacities. Designing and investing in structural and non-structural flood management activities would reduce the vulnerability of the population to future flood events.

The Flood Management Master Plan for the Greater Metro Manila Area was prepared by the Government of the Philippines through the Department of Public Works and Highways (DPWH), with technical and financial assistance of the World Bank. Among the main large-scale priority interventions that were identified in the said master plan is the construction of a high dam in the upper Marikina river catchment area to reduce the peak flows entering the city during typhoon and other extreme rainfall events. At the end of rainy season, the dam will store water which will be released during dry season for supplementing raw water for water supply to Metro Manila and vicinity areas.

Overview and Scope: The Philippine Programmatic Trust Fund (PH-PTF) Grant and associated government funds finance the preparation of feasibility and design studies for a high dam in the upper Marikina River catchment area. For the World Bank, OP 4.01, Environmental Assessment, is triggered since the studies are expected to lead to investments expected to have positive but also potentially adverse environmental and social impacts if not managed adequately. On the side of the Philippine Government, the project proponent or DPWH must secure an Environmental Compliance Certificate (ECC) from EMB-DENR prior to implementing the dam construction. The Project Impact Areas includes the Greater Metro Manila Area and the barangays along the Marikina River in the municipalities of San Mateo, Tanay, Antipolo, and Rodrigues in Rizal Province.

The Environmental and Social Consultant is to undertake the Environmental and Social Impact Assessment (ESIA) in line with WB’s environmental and social safeguards and their policy objectives and following the Philippine Environmental Impact Statement System or Presidential Decree (PD) 1586, the DENR Department Administrative Order DAO No. 2003-30 or the Implementing Rules and Regulations of PD 1586, and all applicable laws, guidelines and regulations.

Other safeguard policies of the WB that triggered by the project are the following:

1) Natural Habitats OP/BP 4.04 2) Forests OP/BP 4.36 3) Physical Cultural Resources OP/BP 4.11 4) Indigenous Peoples OP/BP 4.10 5) Involuntary Resettlement OP/BP 4.12 6) Safety of Dams OP/BP 4.37 It is expected that the ESIA shall address the above policy concerns in an ESIA level of details. A Resettlement Policy Framework Plan and Indigenous People Framework Plan will be integrated into the ESIA Report.

The environment and social impact assessments for the Upper Marikina Dam will carefully assess the environment and social impacts including impacts from ancillary facilities as well as cumulative impacts, and lay out detailed plans for mitigation in the Environmental and Social Management Plan (ESMP), and develop a monitoring and reporting program. The ESMP will be properly costed to ensure that the costs get adequately incorporated into the overall investment proposals. The various options in terms of sites, alignments, and



PROJECT SUMMARY |xvi

resettlement/re-housing will also be analyzed as part of the ESIAs. A Grievance Redress Mechanism will be developed and will be detailed in the ESMP and be presented to the communities during public consultations.

The ESIA will identify natural habitats and other ecologically sensitive areas that may be affected by the investments when implemented. The project will not design activities that would significantly convert or degrade critical natural habitats. If the ESIA indicates that a project would significantly convert or degrade non-critical natural habitats, or affect physical cultural resources, the project would include acceptable mitigation measures to be implemented when the investments are financed. Such mitigation measures could include, as appropriate, minimizing habitat loss (e.g. strategic habitat retention and post-development restoration) and establishing and maintaining an ecologically similar protected area, as well as avoidance or preservation of physical cultural resources. The ESIA will confirm the project impacts on forests and forest-dependent communities, particularly in and around the proposed dam site. As needed, the ESMP will include measures to address impacts on forests, forest health, and forest-dependent communities.

Since the project will entail the design of a high dam as one of its investments, the OP on Safety of Dams is triggered. The policy requires that experienced and competent professionals design and supervise construction, and that the borrower adopts and implements dam safety measures throughout the project cycle.



PROJECT SUMMARY |xxii

PROJECT DESCRIPTION FOR SCOPING



INTRODUCTION | 1

1. INTRODUCTION

1.1 Project Background and Rationale

Typhoons and related flooding are regular events in the Philippines, with an average of 20 typhoons affecting the country per year. There seems to be a trend towards more numerous and more devastating floods in recent years, especially caused by human activities such as deforestation and rapid urbanization, and possibly by climate change. Metro Manila and the adjacent areas of Laguna de Bay and part of Bulacan Province, hereafter called the Greater Metro Manila Area, have not been spared during the past years. Considering that the Greater Metro Manila Area contributes about 35 percent to the economy of the Philippines and is home to around 17 million people, recurrent flooding has a negative impact on millions of people’s lives and the economy. This is worsening over time with rapid urbanization and land availability issues, requiring especially informal settler families (ISF) to live in danger zones. On September 26, 2009, one of the most severe tropical storms in history, Ondoy (internationally named Ketsana), affected the Greater Metro Manila Area. It caused substantial damage and losses, equivalent to 2.7 percent of Gross Domestic Product (GDP).

The adverse impacts on the productive sectors were largely due to damaged or lost inventories, raw materials, and crops. In addition, business operations were interrupted by access problems, power and water shortages, damaged machinery, and absent employees, which contributed to an overall reduction in production capacity. The Master Plan identified that a dam in the upper Marikina River catchment area would be the best structure to reduce the river flows to Metro Manila during major typhoon activity. Grants from the Philippines Programmatic Trust Fund (PH-PTF), which is being administered by the World Bank on behalf of Australia’s Department of Foreign Affairs and Trade (DFAT), and Japan Policy and Human Resources Development (PHRD) shall finance the development of feasibility study and the detailed engineering design of priority infrastructure.

Figure 1-1 Artist’s rendering of the Upper Marikina Dam



INTRODUCTION | 2

The proposed UMD project objective is to improve flood management and urban resilience in the Greater Metro Manila Area. Based on mathematical models linked to flood hazard maps and a detailed assessment of a long list of options, the Master Plan proposes a program of priority infrastructure to safely manage major flood events in the Greater Metro Manila Area. Among the key priority interventions that have been identified are: (i) a high dam in the upper Marikina River catchment area to reduce the peak flows entering the city during typhoon events; (ii) flood protection works in the Marikina River; (iii) land raising of certain sections of the flood plain of Laguna de Bay to protect the population against high water levels in the lake; and (iv) further development of a comprehensive flood forecasting system and monitoring and early warning system for the Greater Metro Manila Area, with maximum participation of local communities. The Upper Marikina Dam construction shall be the subject of this ESIA.

The feasibility study and preparation of detailed engineering design of the Proposed Upper Marikina Dam Greater Metro Manila Area Flood Management Project are being undertaken by a group of consultants led by DOHWA Engineering Co., Ltd. (DOHWA). CHACHI Civil Engineering Services is commissioned as a subcontractor to provide consultancy services to undertake the Environmental and Social Impact Assessment (ESIA) of Upper Marikina Dam Project.

1.2 ESIA Objectives

In general, the objective of the consultancy services for this ESIA is to prepare the environmental impact assessment documents and gather all endorsements from various stakeholders required in securing the ECC for the Upper Marikina Dam project. The specific objectives are as follows:

1) Present the legal, administrative and policy framework for the ESIA so that it is consistent with

WB environmental and social safeguard policies and operating procedures and compliant with

all applicable government rules and regulations;

2) Prepare the Environmental Impact Statement (EIS) in accordance with the governing legal,

administrative and policy framework particularly the Philippine Environmental Impact

Statement System or Republic Act No. 9275, DENR Department Administrative Order DAO No.

2003-30 or the Implementing Rules and Regulations of Presidential Decree No. 1586,

Establishing the Philippine Environmental Impact Statement System) and its Revised

Procedural Manual of 2007 or MC 2007-002, the newly issued DAO No. 2017-015 or the

Guidelines on Public Participation under the Philippine Environmental Impact Statement

System (PEISS), WB’s applicable social and safeguard policies, and all applicable laws, rules,

policies, guidelines and/or regulations;

3) Carry out the ESIA in close coordination with the feasibility and detailed design consultants of

the Proposed Upper Marikina Dam Greater Metro Manila Area Flood Management Project led

by DOHWA;

4) Prepare the ESIA document in coordination and consultation with WB project representatives

and the ESSD of DPWH; and

5) Participate in public hearings and EIA review meetings required by EMB.



BASIC PROJECT INFORMATION |3

2. BASIC PROJECT INFORMATION

1.3 Project Information

Project Name: UPPER MARIKINA DAM GREATER METRO MANILA AREA FLOOD MANAGEMENT PROJECT

Project Location: The Upper Marikina Dam shall be located at Brgy. San Rafael, Municipality of Rodriguez, in the Province of Rizal located directly east of Metro Manila. The dam was proposed to be constructed at about four (4) km upstream from the existing Wawa Dam in Montalban Gorge.

Project Classification & Type:

Classification: Infrastructure Type: Dams

Project Size: 1) Dam Height: 70 meters 2) Catchment Area: 971.4 square kilometers (for confirmation) 3) Crest of Dam: EL.110m 4) Length of Dam: 263m 5) Storage for flood control: 67MCM 6) Sediment: 7.5MCM 7) Storage for water supply: 8.9MCM 8) Water Storage Capacity: 83.8 million cubic meters 9) River Catchment Area: 259 square kilometers 10) Spillway: Spillway with Gate + Spillway with Non-gate

Project Benefits: 1) To reduce flooding occurrences and therefore avoidance of social and economic losses due to flood damages on personal properties, commerce and businesses, and productive capacities

2) To reduce flood damages to infrastructure and social support services 3) Provide water supply to Metro Manila 4) Labor and employment benefits during project construction and operation and

maintenance. 5) Improve living conditions of Project Affected Persons (PAPs) through

resettlement program with livelihood assistance.

Project Cost: Construction Cost = PHP 8,632, 961,990

1.4 Proponent Profile

Proponent: Main Office:

DEPARTMENT OF PUBLIC WORKS AND HIGHWAYS Bonifacio Drive Port Area 652 Zone 068, Manila, 1018 Metro Manila Contact Person: PATRICK B. GATAN, CESO III Project Director, DPWH, FCMC-UPMO

Project Consultant: Feasibility Study Detailed Design Bidding Document

DOHWA ENGINEERING CO., LTD. UPPER MARIKINA DAM - PMO DPWH 2nd Rizal District Engineering Office Westbank Road, Manggahan Floodway Rosario, Pasig City Contact Person: Kim, Myong-Nim



BASIC PROJECT INFORMATION |4

Team Leader

Subcontractor: ESIA and ECC acquisition

CHACHI CIVIL ENGINEERING SERVICES Project Office: Lot 7 West Los Angeles Street, California Village Novaliches, Quezon City 1116 Metro Manila Philippines Telefax. No. (632) 282 4242 Email: [email protected] Contact Person: Louernie F. de Sales, Ph.D. Team Leader and Environmental Specialist Telefax. No. (632) 417 8888 Email: [email protected]



PROJECT DESCRIPTION|5

3. PROJECT DESCRIPTION

1.5 Project Location and Area

1.5.1 Project Location

The proposed Upper Marikina Dam shall be in San Rafael, Rodriguez, Rizal in the northern section of the Pasig-Marikina River Basin. The eastern side is mountainous and forms part of the Southern Sierra Madre Mountain Range in Luzon Island. The Marikina River forms a gorge in the most upstream reach and a valley with hilly to gentle topography in the upstream to midstream reaches. The topography becomes rather gentle to flat land to the westward direction along the lower reach of the Marikina River as well as along the Pasig River.

The catchment area of the Pasig-Marikina River Basin is 641 sq.km., broken down into 103, 89 and 538 square kilometers of drainage areas for Pasig River, San Juan River, and Marikina River, respectively. Marikina River used to be an important transport route during the Spanish colonial era until the Philippines' national highway system became more established. The resulting lack of river boat traffic and the deforestation of the upland areas in what is now the Upper Marikina River Basin Protected Landscape contributed to the river's siltation reducing further its transportation importance.

In Brgy. Wawa in Rodriguez, the Marikina River is dammed by Wawa Dam, a structure built during the early 1900s to provide water for Manila. From Rodriguez, the river flows through San Mateo then to its namesake city of Marikina. In Pasig City, the river meets the gates of the Manggahan Floodway, a controlled waterway used to prevent flooding in Manila during heavy rains by diverting most of the water from Marikina towards Laguna de bay instead of Pasig River. Located 6.75 km downstream is the confluence of Marikina and Pasig Rivers.

The river's depth ranges from 3–21 m and spans from 70–120 m. It has a total area of nearly 75.2 hectares and is 27 kilometers long. The riverbank has an elevation of eight (8) m above sea level at the boundary of San Mateo and Marikina. This slowly goes down at an elevation of four (4) m nearly before the Malanday and Santo Niño boundary. There is an unconfirmed claim that its lowest elevation is along Calumpang which is two (2) m above sea level.

The Marikina River has a number of tributaries in the form of creeks and rivers, and at least one former river-section in Marikina's Barangay Tumana from which its flow has been diverted. These tributaries drain four municipalities (Baras, Rodriguez, San Mateo, and Tanay) and one city (Antipolo) in the Province of Rizal, and three cities in the Philippines' National Capital Region (Pasig, Marikina, San Juan). The biggest of these tributaries are upstream in the more mountainous areas of Rodriguez. This includes the Tayabasan and Montalban Rivers, the Boso Boso River, and the Wawa River, which meets the Marikina River just upstream of Wawa Dam. Further downstream from the dam, but still in the town of Rodriguez are the Puray River (which flows near Avilon Zoo), and the Manga River.

Up till this point the river follows an East-West direction until San Jose, Rodriguez, where it takes a sharp North-South turn towards the Municipality of San Mateo, where the Ampid River forms the boundary between Barangays Maly and Ampid. At this point across the River in Quezon City, Calamiong Creek drains Barangay Bagong Silang. Further downstream the Nangka River and its own tributary in the Sapang Labo Creek mark the Boundary between San Mateo and Marikina (Figure 3-1).

Attachment 1 shows the project location in a larger scale in a NAMRIA procured topographic map.




Figure 3-1 Project Location, Proposed Upper Marikina Dam

1.5.2 Area of Influence (AoI)

The project’s area of influence, which is the area likely to be affected by the project, including all its ancillary aspects includes:

1) The entire catchment area of the Upper Marikina River Basin which is the upper area of the drainage basin of the Marikina River. The area is 26,125.64 hectares covering the upper reaches of the Marikina watershed in the Province of Rizal, flowing through the Antipolo, Baras, Rodriguez, San Mateo, and Tanay. In Rodriguez, the river is dammed by Wawa Dam, a structure built during the early 1900s to provide water for Manila. It is also surrounded by significant bodies of water such as the Boso-Boso River, Sapa Bute-Bute, Tayabasan River, Montalban River and the Wawa Dam.

2) the UMD site and immediate surroundings, i.e. the site of the dam and ancillary infrastructure: construction site, workers' settlements, access roads, areas required for construction material borrow, etc.;

3) in terms of flood control benefits, the project’s area of influence includes the Greater Metro Manila Area.




Photo 3.1 Montalban Gorge

Photo 3.2 Visualization of UMD through the Montalban Gorge

Figure 3-2 shows the general layout of the entire flood control program downstream of the proposed dam. The coverage area for the Upper Marikina Dam is shown in Figure 3-3, UMD catchment area. The positions of the three alternatives sites are shown in Figure 3-4.

1.6 Impact Areas

1.6.1 Direct Impact Area (DIA)

Based on Annex 2-2 of MC 2007-002 or the Revised Procedural Manual (RPM) for DAO 03-30, the Direct

Impact Area (DIA) is initially delimited during the Pre-EIA Study Stage as the area where all project

facilities are proposed to be constructed/situated and where all operations are proposed to be

undertaken. For most projects, the DIA is equivalent to the total area applied for an ECC. The Revised

Procedural Manual includes buffer zones into the limits of the DIA where a particular environmental

equality is also affected.

For the UMD, these areas are the locations of the dam, reservoir, access roads, and facilities including

storage and disposal sites of borrow materials and wastes, also referred to as ancillary facilities. DIA is

initially delimited in terms of impact on natural habitats as affected by the inundation of the area; and

on the need for involuntary resettlement resulting from the acquisition of the project site and right-of-

way (ROW). If the zone of impact on natural habitats is considered, the DIA may also include the

downstream area of the Upper Marikina River where the freshwater ecology may also be directly

affected by the change in water flow due to the dam.




Figure 3-2 General Layout of Flood Controls dowsnstream of UMD




Figure 3-3. UMD Catchment Area

This UMD catchment area spans eleven (11) barangays in three (3) municipalities and one city in the province of Rizal (Table 3.1). The province is located east of Manila and accessible via Ortigas Avenue, Marcos or Smiling Highways.




Table 3.1 List of barangays in the catchment area of UMD

Municipality/City Barangays in Catchment Area

Rodriguez Puray, San Rafael1, Burgoz, Geronimo

San Mateo Pintong Bukawe

Antipolo City San Juan, Calawis, Bagong Nayon, Inarawan, San Jose

Tanay Cayumbay

Within the DIA are the locations of the dam, reservoir, access roads, and facilities including storage and

disposal sites of borrow materials and wastes, also referred to as ancillary facilities. Figure 3-4 shows

the alternative locations of the dam in a topographic map from NAMRIA.

Figure 3-4 UMD Location Alternatives

1.6.2 Indirect Impact Area (IIA)

Annex 2 of the RPM states that IIA during the pre-EIA Study can only be assumed or qualitatively estimated but may be guided by secondary data and information from key interviews of reliable local authorities. IIA is clearly delineated only after the EIA Study is done, and is more accurately established during post-ECC monitoring. The socio-cultural IIA shall be based on the area of influence of the biophysical IIA. For the biophysical environment, the IIA may be the area from the outer boundary of the mixing or buffer zone to the point or area where the baseline environmental quality is calculated or monitored to be met.

1 San Rafael is the location of the dam site.




For the UMD, the areas outside the reservoir where the biophysical environment is affected is IIA. IIA will be initially delineated according to impacts on the natural habitat including the affected terrestrial and freshwater ecosystem; where displacement of people, including IP concerns may be triggered.

In terms of the environmental impact to the natural ecosystem, except those areas tagged above as DIA the entire catchment area of the Upper Marikina River is set as the IIA. The indirect impact areas as a result of the need for involuntary resettlement due to the dam project and downstream flood control structures will potentially be the barangays along the Marikina River in the municipalities of San Mateo and Rodriguez in Rizal Province.

1.7 Regional Impact Zone (RIZ)

Areas that may be positively benefited by the project due to reduction in flood damages are considered within the RIZ. RIZ pertains more to the general area where the impact of the project would be felt, such as the entire municipality, province or region. This project is an important component of the flood control master plan covering the Greater Metro Manila Area and adjoining municipalities of surrounding provinces. The RIZ can be visualized using Figure 3-5 which shows all river, drainage and lake basins in the zone. The area covers the Laguna Lake Basin, four river basins and three drainage basins, such as:

1) Pasig-Marikina River Basin 2) Manila Core Area Drainage Basin 3) Malabon-Tullahan River Basin 4) Malabon-Navotas Drainage Basin 5) Meycauayan River Basin 6) Laguna Lake (including the inflow rivers to Laguna Lake) 7) South Parañaque-Las Piñas River Basin 8) Parañaque-Las Piñas Drainage Basin

The catchment area, river length, and pertinent features of these basins relative to their contributions to flooding in the RIZ are summarized in Table 3.2.

Table 3.2 Features of River Basins, Drainage Basins and the Laguna Lake Basin

River Basin Catchment Area (km2)

River Length (km) Remarks

1) Pasig-Marikina RB 641 52.2 (Pasig River: 17.1, Marikina River up to

Wawa: 35.1)

Pasig River: 103km2 including San Juan River (89km2)

Marikina River: 538km2.

2) Manila Core Area DB 73 Drainage area with/without direct pumps to Manila Bay.

3) Malabon-Tullahan RB 70 26

4) Malabon-Navotas DB 20 Drainage area with/without pumps to Manila Bay except that in Malabon-Tullahan River Basin.

5) Meycauayan RB 171 52 (Including Marilao River)

6) Laguna Lake (including the inflow rivers into Laguna Lake)

3,281 40 (Maximum length of the lake of south-

north stretch)

Lake area: about 900km2

Shore line: about 285 km Inflow rivers: about 100

7) South Parañaque-Las Piñas River Basin

101 13 Including Zapote River Basin (47km2).

8) Parañaque-Las Piñas DB 15 Pump drainage area and/or direct drainage area to Manila Bay.




River Basin Catchment Area (km2)

River Length (km) Remarks

Total Area 4,373

Discussions on project benefits will be included in the ESIA to highlight the importance of the project to the RIZ and how these benefits will outweigh the negative environmental and social impacts and the residual impacts that are unavoidable despite instituting mitigating measures. Inputs from the project economist working under the feasibility study into the ESIA will be required for this task. The RIZ will cover the Greater Metro Manila Area and its surrounding areas.

Figure 3-5 River Basins, Lake Basin, and Drainage Basins in the Greater Metro Manila Area




1.8 Project Components List

The Master Plan proposes a 70-m high gravity concrete dam with large orifice openings as one of the large programs of priority infrastructures to safely control and manage major flood events in Metro Manila. The gross storage capacity of the proposed dam is around 80 million m3/s which would be sufficient to reduce the peak river flow during a 100-year event from about 3,600 to 900 m3/s. The master plan cites the Yokohama Dam in Japan as a closely similar structure (Figure 3-6). Although the primary purpose of the proposed dam would be flood management, the Master Plan identified that there are opportunities to utilize some of the reservoir water for much needed water supply purposes for Metro Manila as well.

Figure 3-6. The Yokohama Dam - a similar structure to UMD

Typical cross sections of the dam are shown in (Figure 3-7). The dam components are still in the planning stage and their locations are still being determined. The components will likely include the following:

a. Reservoir, intake and dam b. Magazine area c. Contractor's and engineers’ office d. Fuel dump area e. Quarry areas f. Contractor's laydown area g. Contractor's camp h. Batching plant i. Access Road

The flood management master plan has an estimated cost of PhP352 billion (USD7.86 billion) for its implementation within 23 years. Aside from investments in large program of priority infrastructures, the master plan also presents proposals for non-structural measures as flood forecasting, early warning systems, and community-based flood risks management. It also has recommendations to improve the institutional structure to deal with flood with flood management in an integrated manner. The other main large-scale priority interventions that have been identified in the said master plan are as follows:




(a) provision of flood protection works in the Marikina River, upstream of the proposed Phase IV and V of the Pasig-Marikina River Channel Improvement Project (PMRCIP).

(b) land raising or another similar development along the western shore of Laguna de Bay to protect the population against high water levels in the lake (as the designed solution will most likely involve, land raising, as also proposed in the master plan, this is referred to in the rest of the text, although there is still a possibility that a more preferred option is selected at the feasibility stage); and

(c) participation of local communities.

Figure 3-7 Typical Dam Sections



PROJECT DESCRIPTION |14

2.6 Project Phases, Key Environmental Aspects, Wastes, Issues, Built-in Measures

The PH-PTF Grant and associated government funds currently finances the preparation of feasibility and design studies for a high dam (or other flood management structure) in the upper Marikina River catchment area. The government finances the social and environmental impact assessments including the social surveys that will target the communities that are affected by the potential projects that may need to be resettled, related to this intervention as well as intervention for which the technical studies will be funded from the PHRD Grant.

Upon completion of the feasibility study and prior to the preparation of the detailed design of the preferred option, the results will be submitted first to NEDA for deliberation/evaluation and subsequent approval that will become the basis of the project design stage.

The project is still under the Feasibility Study stage and project phasing is yet to be established while the project components are yet to be identified. These components will become available in time for the three-level scoping process.

Key environmental aspects likely to be affected are shown below together with the potential impacts of the project during construction and operations phases

PROJECT PHASE / ENVIRONMENTAL

ASPECT

ENVIRONMENTAL COMPONENT LIKELY

TO BE AFFECTED POTENTIAL IMPACT

CONSTRUCTION STAGE A. Land Land Use 1) Inconsistency with land use

2) Encroachment in ECAsGeology / Geomorphology

- Change in surface landform/ topography/terrain/slope

KEY ENVIRONMENTAL COMPONENTS LIKELY TO BE AFFECTEDkk





ASPECT



Pedology 1) Inducement of subsidence, liquefaction, landslides,

mud / debris flow2) Soil erosion / Loss of topsoil/overburden3) Change in soil quality/fertility

Terrestrial Ecology 1) Removal of vegetation (including reforestation treesplanted under the NGP)

2) Loss of important local species3) Loss of habitat for wildlife species4) Hindrance to wildlife access

B. Water Hydrology 1) Change in drainage morphology2) Change in stream/ water depth due accrued sediments

on the riverbed3) Occurrence or aggravation of flooding in nearby areas4) Depletion/ Competition in water resource use

Freshwater Ecology 1) Alteration of natural flow and threat to existence ofspecies

Water Quality Water quality degradation through:

a) Sediments from open areas reaching the waterwaysb) Solid and liquid wastes from construction area and

workers’ campsc) Run-off from excavated materials reaching the

waterwaysd) Waste from equipment and vehicles repairs

C. Air Ambient Air Quality 1) Ambient air quality impacts due to fugitive dust fromground clearing operations, structure erection andfrom vehicles plying access roads

2) Effects of Vibrations:a) Dust from blasting activities, access road

construction, and hauling waste rock to wasterock disposal areas

b) Emission of standard pollutants from vehiclesand heavy equipment operation

Ambient Noise Quality Increase in ambient noise level during construction D. People 1) Displacement of settlers

2) Displacement of Property/ Conflict in Land Ownership3) Right of Way Conflict4) Increased in-migration that may result in:5) Proliferation of informal settlers6) Competition in the delivery of basic services7) Lifestyle change:8) For IPs who have their own cultural norms and practices9) For rural residents in terms of

a) increased traffic; increased videoke, drinking places; possibly increasedprostitution; urbanization

b) More tourists are expected to come in the sacred stone (Istampang Bato)that possibly increased solid waste, which can be harmful to the aestheticsof the place

10) Threats to Public Health/Safety:a) Increased accidents (traffic and construction related)





ASPECT



b) Increased incidences of petty crime and disorderly conductc) Proliferation of alcohol, drugs, prostitution, gambling

11) Increased employment opportunities12) Increased small-business, retail, trading, service and transportation business

opportunities

DURING OPERATIONS A. Land Geology /

Geomorphology Scouring of downstream of spillway

Pedology Soil erosion / Loss of topsoil/overburden Terrestrial Ecology 1) The loss of terrestrial wildlife to drowning during

reservoir filling2) Reduced river flow can impede essential biophysical

functions and modify flow patterns and floodingcharacteristics along river stretch. This will lower thewater levels along this stretch and there will be slightchanges in species composition towards moredroughts tolerating plant species along the River.

E. Water Hydrology 1) Sedimentation behind the dam2) Change in drainage morphology3) Reduction in volumetric flow4) Change in stream/water depth5) Depletion of water6) resources/competition in water use7) Occurrence or aggravation of flooding in nearby areas

Freshwater Ecology 1) Disruption of fisheries due to changes in flow, blockingof fish migration, and

2) changes in water qualityWater Quality 1) Decrease in dissolved oxygen levels in water due to

thermal stratification2) Degradation of water quality in the reservoir

C. Air Air Noise

1) Contribution to climate change due to greenhouse gasemissions

2) Noise GenerationD. People 1) Displacement of settlers during flood events at lower reservoir/ Dam Break

2) Right of Way Conflict3) Threat to Public Health/Safety4) Flood control5) Increased LGU revenue from

a) ER 1-94b) Payment of annual taxes and permits

6) Complaints of effects and impacts of the project on various aspects of people’slives

7) Constraints on health facilities, school facilities and employment opportunitiesin the area

2.7 Project Cost and Duration

Construction Cost = PhP 8,632, 961,990

PROCESS TECHNOLOGY AND ALTERNATIVES

To determine the optimal scale of dams and other appurtenances, a hydraulic, hydrological

analysis will be performed using rainfall data, and streamflow data from the station which is

located around the project areas.

Table 3. Hydrological Analysis Process

Item Major issues Application

Rainfall

analysis

&

Estimation

of

Flood

Basin-wide

mean

&

areal rainfall

• Estimate basin-wide mean rainfall

using the Thiessen network • Estimate areal rainfall using ARF

(Areal Reduction Factor)

• Used to determine the

optimal scale of structures

• Used to assess a hydrological

stability

• Used to assess flood control

capacity

• Used to determine reservoir

operation level

• Used to identify impacts on

the upper/lower river

Probable

Rainfall

• Derive annual maximum series of

duration rainfall data • Estimate probable rainfall by

frequency (i.e. return period)

Flood

• Estimate flood using the SUH

(synthetic unit hydrograph)

method • Test & correct estimated flood

using historical large-flood data

The consultant will develop a detailed historical climate and water resources database for

the Upper Marikina Catchment Area. Organize the data in electronic form in order to allow

future data entry/updating, and a fast way of retrieving it for various purposes using easy

data retrieval methods;

The consultant will review the mathematical model prepared under the Metro Flood

Management Master Plan and the one prepared by JICA for the review of proposals under

the Pasig-Marikina river Channel Improvement Project if available. The model should have

a capacity to stimulate the design flood event in the Marikina River and be able to propose

different interventions, techniques, and operation rules to minimize the flood discharges in

the Pasig-Marikina River system by optimizing the retention or diversion of flood waters in

the Upper Marikina Catchment Area;

(4) Selection of the preferred flood management structure in the upper Pasig-Marikina

watershed.

The consultant will review other possible flood management infrastructure options and select

the most efficient and structurally stable flood management structure as the preferred option

for development.

The Consultant will analyze & evaluate structure stability, constructability, economic

feasibility and layout plans for major structures at the alternative sites to determine optimal

dam type and location The main processes of dam design are as follows.

Figure 8. Process of Dam design

Table 4. Comparison among different dam types

Item Concrete Dam Zone & Core Dam Concrete Face Rockfill

Dam

Schematic

diagram

Dam height

• No specific limitation

in dam height


in dam height

• In general, 100m or

lower recommended

(to prevent problems

with the settlement of

body)

Availability of

construction

materials

• Applicable to cases

where it’s easy to

procure aggregates.


where all kinds of

materials are

available


where it’s difficult to

procure soil materials

Meteorologica

l conditions


in meteorological

conditions

• Limited in core

constructability


in meteorological

conditions

Topographical

constraints


in topographical

conditions


in topographical

conditions

• Not recommendable

in cases where both

banks are sharply

sloped, which may

accompany

differential settlement

Geological

conditions

• Mainly applicable to

rock mass foundation


sand & gravel

foundation or rock

mass foundation


rock mass foundation

Earthquake • Relatively safe for

earthquakes

• Relatively vulnerable

to earthquakes

• Relatively safe for

earthquakes

(5) Preparation of feasibility study that determines possible options and settles on preferred

option through economic evaluation including social and environmental impact assessment

The consultant will prepare the preliminary engineering designs for possible structures and

facilities. If selected, special attention should be paid in optimizing the height of the dam

and the reservoir volume to have maximum benefits to the design of the spillway gates to

allow several discharge operation patterns that may change over time due to climate change

or other factors, and to the fact that the proposed dam site is near an active fault.

Figure 9. Preliminary Design of Marikina Dam.

The Consultant will determine the optimal capacity of a spillway which is hydraulically safe

enough to resist against design flood discharge, and optimal energy dissipator type.

Table 5. Comparison among different spillway types

Item Description

Open

channel

types

Overflow

• Allow overflow by lowering the

elevation of dam crest

• Shape the longitudinal profile of a

spillway into the lower part of nappe

where the sharp-edged weir is fully

overflowed

Ogee

• Overflow → Chute way → Lower

river

• Mainly applicable to an open-

channel-type chute spillway

•

Side

channel

• Parallel between the centerlines of

overflow weir and side channel

• Applicable to cases where it’s

difficult to sufficiently secure

spillway length

•

Tunnel

channel

types Tunnel

• Install a tunnel to drain out flood

discharge

• Lower the sectional area of stream

flow to smaller than 75% of that of

pipes to keep the inside of an

outflow pipe in open-channel state

Siphon

• Applicable to cases where flood

scale is small and installation space

is limited

• Design reservoir level so that it may

automatically lie within a specific

range

•

Shaft

• Morning-glory-shaped shaft

spillway into which water is

overflowed

• Inlet section: Morning-glory-shaped

• Applied in line with an auxiliary or

emergency spillway

•

Free overfall

spillway

•

• Induce the free overfall of stream

flow from a weir

• Construct a saddle dam in a lower

river to make an artificial reservoir

and thereby provide against erosion

where stream flow falls down

The Consultant will determine the optimal method of river diversion works in terms of

constructability, stability and economic feasibility considering the following issues:

Table 6. Optimization of river diversion

Item Full-scale coffering Partial coffering Step-by-step coffering

Schemati

c

Drawing

• • •

Features

• The diversion tunnel

can be used as water

inlet and discharge

facility

• Increase of construction

period and cost

• Not able to use the

cofferdam crests as

construction roads

• Reduction of

construction period and

cost

• The cofferdam crests

can be used as

construction roads

• Reduction of

construction period

and cost,

environmental and social impact assessment of the...

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