f. hydrologic/inundation analyses and preliminary...

F. Hydrologic/Inundation Analyses

and Preliminary Design for Model River Basins

The Study on the Nationwide Flood Risk Assessment and the Flood Mitigation Plan for the Selected Areas in the Republic of the Philippines

Supporting Report FTable of Contents

Table of Contents Page

1 GENERAL ............................................................................................................................................F- 1

2 HYDROLOGIC ANALYSIS ................................................................................................................F- 1

2.1 Project Scale...................................................................................................................................F- 1

2.2 Design Flood Discharge .................................................................................................................F- 1

2.2.1 Estimation Method of Design Flood Discharge ......................................................................F- 1

2.2.2 Design Flood Discharges and Distribution..............................................................................F- 2

3 FLOOD INUNDATION........................................................................................................................F- 8

3.1 Flow Capacity ................................................................................................................................F- 8

3.1.1 Calculation Method .................................................................................................................F- 8

3.1.2 River Cross Section Data ........................................................................................................F- 8

3.1.3 Flow Capacity .........................................................................................................................F- 10

3.2 Flood Inundation Analysis .............................................................................................................F- 13

3.2.1 Analysis Method......................................................................................................................F- 13

3.2.2 Hydrologic / Hydraulic Boundary ...........................................................................................F- 13

3.2.3 Analysis Conditions.................................................................................................................F- 14

3.2.4 Adjustment of SRTM/NASA Data ..........................................................................................F- 15

3.2.5 Flood Inundation Area.............................................................................................................F- 15

4 PRELIMINARY DESIGN OF STRUCTURAL MEASURES .............................................................F-24

4.1 Design Conditions ..........................................................................................................................F- 24

4.1.1 Channel Alignment..................................................................................................................F-24

4.1.2 Longitudinal Profile and Cross Sections .................................................................................F- 24

4.1.3 Freeboard.................................................................................................................................F- 24

4.1.4 Manning’s Roughness Coefficient for Improved Channel ......................................................F- 25

4.2 Preliminary Design.........................................................................................................................F- 25

4.2.1 Ilog-Hilabangan River.............................................................................................................F- 25

4.2.2 Dungcaan River.......................................................................................................................F- 27

4.2.3 Meycauayan River...................................................................................................................F- 28

4.2.4 Kinanliman River ....................................................................................................................F- 30

4.2.5 Tuganay River .........................................................................................................................F- 31

4.2.6 Dinanggasan River ..................................................................................................................F- 33

JICA CTI Engineering International Co., Ltd. F-i

Supporting Report F Table of Contents

List of Tables

Table Table F.2.1 Project Scale and Previous Related Studies.....................................................................F- 1

Table F.2.2 Constants for Regional Specific Discharge Curve ..........................................................F- 2

Table F.2.3 Methods of the Design Discharge Estimation .................................................................F- 2

Table F.2.4 Constant Applied for Tuganay River ...............................................................................F- 5

Table F.2.5 Sub-Basin Areas and Design Discharges of Tuganay River ..........................................F- 6

Table F.3.1 Minimum Required Freeboard for Dike ........................................................................F- 8

Table F.3.2 Cross Section Survey Points ..........................................................................................F- 9

Table F.3.3 Flow Capacity of Existing River Channel .....................................................................F- 10

Table F.3.4 Water Level at River Mouth ..........................................................................................F- 13

Table F.3.5 Adjustment of SRTM/NASA Data ................................................................................F- 15

Table F.3.6 Flood Inundation Area of the Ilog-Hilabangan River Basin ..........................................F- 15

Table F.3.7 Flood Inundation Area of the Dungcaan River Basin ....................................................F- 16

Table F.3.8 Flood Inundation Area of the Meycauayan River Basin ...............................................F- 16

Table F.3.9 Flood Inundation Area of the Kinanliman River Baisn .................................................F- 17

Table F.3.10 Flood Inundation Area of the Tuganay River Basin ......................................................F- 17

Table F.3.11 Flood Inundation Area of the Dinanggasan River Basin ...............................................F- 17

Table F.4.1 Manning’s Roughness Coefficient .................................................................................F- 25

Table F.4.2 River Channel Improvement of the Ilog-Hilabangan River Basin ..................................F- 25

Table F.4.3 River Channel Improvement of the Dungcaan River Basin ............................................F- 27

Table F.4.4 River Channel Improvement of the Meycauayan River Basin ........................................F- 28

Table F.4.5 River Channel Improvement of the Kinanliman River Basin..........................................F- 30

Table F.4.6 Salient Features of Sabo Dam of the Kinanliman River Basin........................................F- 30

Table F.4.7 River Channel Improvement of the Tuganay River Basin...............................................F- 31

Table F.4.8 Dimension of Retarding Basins in the Tuganay River Basin ..........................................F- 32

Table F.4.9 River Channel Improvement of the Dinanggasan River Basin........................................F-34

Table F.4.10 Salient Features of the Sabo Facilities of the Dinanggasan River Basin.........................F- 34

F-ii JICA CTI Engineering International Co., Ltd.

Supporting Report FTable of Contents

List of Figures

Figure Figure F.2.1 Design Flood Distribution of Ilog-Hilabangan River .........................................................F- 3

Figure F.2.2 Design Flood Distribution of Dungcaan River ...................................................................F- 3

Figure F.2.3 Design Flood Distribution of Meycauayan River...............................................................F- 4

Figure F.2.4 Design Flood Distribution of Kinanliman River ................................................................F- 4

Figure F.2.5 Relationship between Catchment Area and Constant ..........................................................F- 5

Figure F.2.6 Sub-basin Division of Tuganay River.................................................................................F- 6

Figure F.2.7 Design Flood Distribution of Tuganay River .....................................................................F- 7

Figure F.2.8 Design Flood Distribution of Dinanggasan River ..............................................................F- 7

Figure F.3.1 Design Flood Discharges and Flow Capacities ..................................................................F-11

Figure F.3.2 River Profile of Ilog River..................................................................................................F-14

Figure F.3.3 Flood Inundation Area of the Ilog-Hilabangan River Basin ...............................................F-18

Figure F.3.4 Flood Inundation Area of the Dungcaan River Basin.........................................................F-19

Figure F.3.5 Flood Inundation Area of the Meycauayan River Basin.....................................................F-20

Figure F.3.6 Flood Inundation Area of the Kinanliman River Basin ......................................................F-21

Figure F.3.7 Flood Inundation Area of the Tuganay River Basin ...........................................................F-22

Figure F.3.8 Flood Inundation Area of the Dinanggasan River Basin ....................................................F-23

Figure F.4.1 Proposed Works of Ilog-Hilabangan River Basin...............................................................F-26

Figure F.4.2 Proposed Works of the Dungcaan River Basin...................................................................F-27

Figure F.4.3 Proposed Works of the Meycauayan River Basin...............................................................F-29

Figure F.4.4 Proposed Works of the Kinanliman River Basin ................................................................F-31

Figure F.4.5 Proposed Works of the Tuganay River Basin .....................................................................F-33

Figure F.4.6 Proposed Works of the Dinanggasan River Basin ..............................................................F-35

List of Figs. Fig. Fig. F-4- 1 Longitudinal Profile and Typical Cross Sections of Ilog-Hilabangan River ................... F-F- 1

Fig. F-4- 2 Longitudinal Profile and Typical Cross Sections of Dungcaan River ............................. F-F- 2

Fig. F-4- 3 Longitudinal Profile and Typical Cross Sections of Meycauayan River ......................... F-F- 3

Fig. F-4- 4 Longitudinal Profile and Typical Cross Sections of Marilao River ................................. F-F- 4

Fig. F-4- 5 Longitudinal Profile and Typical Cross Sections of Kinanliman River........................... F-F- 5

Fig. F-4- 6 Longitudinal Profile and Typical Cross Sections of Tuganay River................................ F-F- 6

JICA CTI Engineering International Co., Ltd. F-iii

Fig. F-4- 7 Longitudinal Profile and Typical Cross Sections of Anibongan River ............................ F-F- 7

Supporting Report F Table of Contents

Fig. F-4- 8 Longitudinal Profile and Typical Cross Sections of Ising River...................................... F-F- 8

Fig. F-4- 9 Longitudinal Profile and Typical Cross Sections of Dinanggasan River......................... F-F- 9

F-iv JICA CTI Engineering International Co., Ltd.

Supporting Report F Chapter 2

F. HYDROLOGIC/INUNDATION ANALYSES AND PRELIMINARY DESIGN FOR MODEL RIVER BASINS

1 GENERAL

Hydrologic/inundation analyses and preliminary design for model river basins are conducted for six (6) model river basins as shown below. The preliminary design for each model river basin is conducted for the recommended plan.

• Ilog-Hilabangan River Basin • Dungcaan River Basin • Meycauayan River Basin • Kinanliman River Basin • Tuganay River Basin • Dinanggasan River Basin

2 HYDROLOGIC ANALYSIS

2.1 Project Scale

The project scale is basically proposed to mitigate the flood damages of less than 20-year return period. However, if there exists the project scale adopted in the previous related study, this project scale is applied. The project scales adopted for respective river basins are shown in Table F.2.1. In this table, the previous studies are also described.

Table F.2.1 Project Scale and Previous Related Studies Name of River

Basins Return Period Previous Studies

Ilog-Hilabangan 25-year Master Plan Report, Study on Ilog-Hilabangan River Basin Flood Control Project, 1991

Dungcaan 20-year None

Meycauayan 30-year Feasibility Study on Valenzuela-Obando-Meycauayan (VOM) Area Drainage System Improvement Project, 2001

Kinanliman 25-year Detailed Design Report for the Pilot Project for Kinanliman River, Real, Quezon, 2007

Tuganay 25-year Report on Preliminary Design of Liboganon River Dike Extension, 1998

Dinanggasan 20-year Basic Study on Disaster Prevention and Reconstruction Project for Camiguin Island, Mindanao, Philippines, 2003*

Note) * : This Basic Study did not refer to the project scale for flood control.

2.2 Design Flood Discharge

2.2.1 Estimation Method of Design Flood Discharge

JICA CTI Engineering International Co., Ltd. F-1

The design flood discharges are basically computed by the Specific Discharge Formula. Basically, this method is applied to a river basin with the basin area of 20 km2 or more (Manual on Flood Control Planning, DPWH). The Specific Discharge Formula is shown below:

q = c・A where, q = specific discharge (m3/s/km2) c = constant (refer to Table F.2.2) A = catchment area (km2)

Table F.2.2 Constants for Regional Specific Discharge Curve Return Period Region 2-year 5-year 10-year 25-year 50-year 100-year

Luzon 15.66 17.48 18.91 21.51 23.83 25.37 Visayas 6.12 7.77 9.36 11.81 14.52 17.47 Mindanao 8.02 9.15 10.06 11.60 12.80 14.00

However, if there exist the design discharges analyzed in the previous study, these design discharges are adopted. Table F.2.3 shows the methods of the design discharge estimation for respective model river basins.

Table F.2.3 Methods of the Design Discharge Estimation Name of River

Basins Previous Studies Remarks

Ilog-Hilabangan Storage Function Model Adopted method in the previous study Dungcaan Specific Discharge Formula Meycauayan Quasi-Linear Runoff Model Adopted method in the previous study Kinanliman Rational Formula Adopted method in the previous study Tuganay Specific Discharge Formula Specific Discharge Formula is modified based

on the previous study. Dinanggasan Specific Discharge Formula Calculation results are adjusted considering

sediment content.

The design discharges applied in this Study are shown in the following sections.

2.2.2 Design Flood Discharges and Distribution

(1) Ilog-Hilabangan River The design flood discharges are set with reference to the previous master plan. In the previous study, the Storage Function Model is applied as a runoff model. In the previous study, rainfall intensity - duration curve was prepared to develop a hyetograph model. Distribution of design flood discharge with 25-year return period is shown in Figure F.2.1.

F-2 JICA CTI Engineering International Co., Ltd.

(A-0.048-1)

Design Discharge：3,690m3/s2,920m3/s

1,930m3/s

Figure F.2.1 Design Flood Distribution of Ilog-Hilabangan River

(2) Dungcaan River The design flood discharges are calculated using the Specific Discharge Formula. Distribution of design flood discharge with 20-year return period is shown in Figure F.2.2.

Figure F.2.2 Design Flood Distribution of Dungcaan River

(3) Meycauayan River The design flood discharges are set with reference to the previous feasibility study. In the previous report, the design flood discharges were computed by the Quasi-Linear Runoff Model, which was developed to express runoff characteristics on variation of land uses. Distribution of design flood discharge for 30-year return period is shown in Figure F.2.3.

Hilabangan River

Ilog River

Hilabangan River

Diversion Channel

Safety Level: 25 Year Return Period

Ilog River

Baybay

Baybay Bridge

Design Discharge :655m3/s

Dungcaan River

Mangrove

River Mouth

Safty Level: 20 Year Return Period

(Residential Area)

(Built-up Area)

Figure F.2.3 Design Flood Distribution of Meycauayan River

(4) Kinanliman River The design flood discharges are set with reference to the previous detailed design. In this detailed design, the flood discharge was calculated with the Rational Formula using the rainfall intensity duration curve of Infanta, Quezon. Since this river is of a debris flow stream, the flood discharge calculated with the Rational Formula is multiplied by 1.5 considering 50% sediment content. The distribution of design flood discharge for 25-year return period is shown in Figure F.2.4.

Figure F.2.4 Design Flood Distribution of Kinanliman River

Manila Bay

Bulacan River

Meycauayan River

Marcos B. MacArhter B.

N.Luzon Highway

Marilao River

Pump drainage area(VOM area)

2,490m3/s

1,500m3/s

990m3/s 580m3/s 320m3/s

340m3/s

730m3/s

Kinanliman River Bridge

FCSEC Pilot in 2007

River Mouth

Design Discharge: 380m3/s

(5) Tuganay River Design discharges are calculated based on the Specific Discharge Formula. For this calculation, the constants are estimated based on the design discharges obtained in the previous preliminary design. The design discharges are estimated based on the following procedures:

① Constants are estimated by the Formula based on the design discharges of previous study and basin areas. In the previous study, flood discharges were calculated by the Unit Graph Method. The estimated constants are shown in Table F.2.4.

② The relationship between the basin areas and the constants is built based on the above data. The relationship is shown in Figure F.2.5.

③ From the relationship, the constant is estimated and specific discharge is calculated.

Table F.2.4 Constant Applied for Tuganay River

River Catchment Area(km2)

Discharge (m3/s) Constant

Tuganay and Anibongan 565.92 543 4.98 Ising 146.38 190 3.67

Figure F.2.5 Relationship between Catchment Area and Constant

In constructing a river system model, the Tuganay River Basin is firstly divided into several sub-basins. River channels connecting the sub-basins are set up together with computation points. Sub-basin areas are shown in Table F.2.5. The sub-basin divisions are shown in Figure F.2.6. Based on these data, the design flood discharges are calculated as shown in Table F.2.5.

1/25 Return Period

y = 0.0031x + 3.2176

0 100 200 300 400 500 600 700Catchment Area：A (km2)

Table F.2.5 Sub-Basin Areas and Design Discharges of Tuganay River Reference Point Total Aea (km2) Discharge (1/25)

TU-M1 572.29 548 TU-M2 565.92 543 TU-M3 416.29 420 TU-M4 317.32 339 TU-M5 232.36 267 TU-M6 105.07 150 TU-A1 145.39 189 TU-A2 116.62 162 TU-L1 80.54 124 TU-P1 82.05 126 TU-B1 88.77 133 IS-M1 172.11 214 IS-M2 146.38 190 IS-M3 143.98 188 IS-O1 16.90 40 IS-O2 13.45 33

Figure F.2.6 Sub-basin Divisions of Tuganay River

IS_O2IS_M3 TU_M2

TU_A2TU_M6

The distribution of design discharge for 25-year return period is shown in Figure F.2.7.

Tuganay BridgeAnibongan Bridge

Anibongan

TangrawBridge

Panaga River

Tuganay River

River Mouth

Lucutan River

Ising Bridge

Old Ising River(Marsh land)

New Bridge(Existing culverts)

Carmen New Ising River

Balagunan River

DujaliAnibongan River

190m3/s

150m3/s

140m3/s

130m3/s

270m3/s

340m3/s

420m3/s

540m3/s

550m3/s

220m3/s

190m3/s

40m3/s

Figure F.2.7 Design Flood Distribution of Tuganay River

(6) Dinanggasan River The design flood discharges are calculated based on the Specific Discharge Formula. Since this river is of a debris flow stream, calculated flood discharge is multiplied by 1.5 considering 50% sediment content. Distribution of design flood discharge for 20-year return period is shown in Figure F.2.8.

Figure F.2.8 Design Flood Distribution of Dinanggasan River

Bridge

Existing Dike

Compol River

Catarman

Compol

River Mouth

Bridge

Tagib River

26m 3/s

Tag-Ibo River

3 FLOOD INUNDATION

3.1 Flow Capacity

3.1.1 Calculation Method

The flow capacity analysis is conducted using HEC-RAS (US Army Corps of Engineers Hydrologic Engineering Center River Analysis System). HEC-RAS is a one-dimensional steady flow hydraulic model designed to aid channel flow analysis and floodplain determination. Flow capacity of the existing river channel is estimated to identify the reach where safety level is lacking and to consider possible alternative plans to accommodate the design discharge. In principle, flow capacity of the existing river channel is estimated by non-uniform flow method using newly obtained data on river cross sections. The calculation is conducted with reference to the manual of the DPWH, and the freeboard shown in the table below is taken into consideration.

Table F.3.1 Minimum Required Freeboard for Dike Design Flood Discharge (m3/s) Freeboard (m)

Less than 200 0.6 200 and up to 500 0.8

500 and up to 2,000 1.0 2,000 and up to 5,000 1.2

The discharge, whose corresponding water level equals to the height, which is current ground elevation or dike elevation minus freeboard, is set as the flow capacity of the existing river channel.

3.1.2 River Cross Section Data

Flow capacities of the rivers are calculated using the cross section data. In this Study, river cross section survey was conducted in order to collect the necessary data. The survey point of each cross section is shown in the tables below.

Table F.3.2 Cross Section Survey Points

Ilog-Hilabangan River Cross Section No. Ilog River Hilabangan River Old Ilog River

CR1 0.96KP --- 0.37KP CR2 5.68KP --- 6.05KP CR3 12.91KP --- --- CR4 18.00KP --- --- CR5 20.24KP --- --- CR6 --- 7.81KP ---

Dungcaan River

Cross Section No. Dungcaan River CR1 0.14KP CR2 0.88KP CR3 1.66KP CR4 2.69KP CR5 3.58KP

Meycauayan River

Cross Section No. Meycauayan River Marilao River CR1 5.06KP --- CR2 8.80KP --- CR3 9.89KP 0.42KP CR4 13.64KP --- CR5 12.94KP 1.06KP CR6 --- 3.58KP

Kinanliman River

Cross Section No. Kinanliman River CR1 0.00KP CR2 0.39KP CR3 0.68KP

Tuganay River

Cross Section No.

Tagum Libuganon

River Tuganay

River Anibongan

River Ising River

Old Ising River

CR1 0.62KP --- --- --- --- CR2 --- 7.69KP --- 11.61KP 3.27KP CR3 --- 10.02KP --- 15.30KP --- CR4 --- 16.23KP 5.31 KP --- --- CR5 --- 17.69KP 6.89 KP --- --- CR6 --- 20.23KP 10.74 KP --- ---

Dinanggasan River Cross Section No. Dinanggasan River

CR1 0.13KP CR2 0.52KP CR3 0.88KP CR4 1.16KP CR5 5.60KP

Note) KP means Kilometer Post, and figures attached to KP means the distance of cross section survey point from the river mouth.

3.1.3 Flow Capacity

Based on the method above mentioned, the flow capacities of the rivers are estimated as shown below.

Table F.3.3 Flow Capacity of Existing River Channel

Ilog-Hilabangan River

Location of Calculation Flow Capacity (m3/sec) Ilog River (upstream portion) 290 - 800

Ilog River (downstream portion) 250 - 2,650 Old Ilog River 250

Hilabangan River 100

Dungcaan River

Location of Calculation Flow Capacity (m3/sec) Downstream of Baybay Bridge 290

Meycauayan River

Location of Calculation Flow Capacity (m3/sec) Meycayayan River

(downstream of confluence point) 400 Meycauayan River

(upstream of confluence point) 140 Meycauayan River (31.4KP) 330

Marilao River (upstream of confluence point) 240

Kinanliman River

Location of Calculation Flow Capacity (m3/sec) Kinanliman River (bridge) 190

Tuganay River

Location of Calculation Flow Capacity (m3/sec) Tuganay River (upstream portion) 75 Tuganay River (Tuganay Bridge) 175

Anibongan River 20 Ising River 8

Dinanggasan River

Location of Calculation Flow Capacity (m3/sec) Dinanggasan River (upstream portion) 180

In order to understand the present condition of the rivers, the design flood discharges and the flow capacities are summarized in the following figures:

Ilog-Hilabangan River:

2,920m3/s (290～800m3/s)

3,690 m3/s (250～2,650m3/s)

Ilog River

Hilabangan River

Diversion Channel(250 m3/s)

Safety Level:

25 Year-Return

With “()”: Flow Capacity

Dungcaan River:

Meycauayan River:

Figure F.3.1 Design Flood Discharges and Flow Capacities (1/2)

Safety Level: 20 Year-Return With “()”: Flow Capacity Baybay

Baybay Bridge 655m3/s

(290m3/s)

Dungcaan River

Mangrove

N.Luzon Highway

（Manila Bay）

Bulacan River

Meycauayan River

Marcos B. MacArhter B.

Marilao River

Pump drainage area

(VOM area)

2,490m3/s

1,500m3/s

990m3/s (400 m3/s) 580m3/s

(135 m3/s)

320m3/s (25 m3/s)

340m3/s

730m3/s (450 m3/s)

Safety Level:

30 Year-Return With “()”:

Flow Capacity

Kinanliman River:

Kinanliman River

FCSEC Pilot Project in 2007

At the bridge (190 m3/s)

380m3/s

Safety Level:

River Mouth

25 Year-Return

Tuganay River:

150m3/s

Tugum-Libuganon River

Tuganay BridgeAnibongan Bridge

Tangraw Bridge

Panaga River

Tuganay River

River Mouth

Lucutan River

Ising Bridge

Old Ising River

New Bridge (Existing culverts)

Diversion channel

Existing Channel

New Ising River

Balagunan River

Dujali

Anibongan River 190m3/s (15 m3/s)

140m3/s

130m3/s

270m3/s

340m3/s

420m3/s (120m3/s)

540m3/s (175m3/s)

550m3/s

220m3/s (80m3/s)

190m3/s(15m3/s)

190m3/s

40m3/s

Carmen

Tugum Bridge

Safety Level:

25 Year-Return

Dinanggasan River:

River Mouth

Dinanggasan River

Bridge

Compol River

Catarman Compol

Bridge Tagib 26m3/s

270m3/s (180m3/s)

Safety Level:

Tag-Ibo River

20 Year-Return

Figure F.3.1 Design Flood Discharges and Flow Capacities (2/2)

3.2 Flood Inundation Analysis

3.2.1 Analysis Method

Software of HRC-RAS and HEC-GeoRAS is used for flood inundation analysis. HEC-RAS is used for one-dimensional steady flow analysis, and HEC-GeoRAS is used for creation of cross section cut lines, flood inundation mapping and others. HEC-GeoRAS is the extension software of ArcGIS. For the flood inundation analysis, the following data are needed:

• DEM (Digital Elevation Model) data of the river system in the TIN (Triangulated Irregular Network) format

• Cross sectional survey data • Design discharge data • Hydraulic boundary data (river mouth water level, etc.)

The salient features of the flood inundation analysis are described below. At first, DEM data are incorporated into HEC-GeoRAS and cross sectional data are created. Then, the water levels of the river are computed using HEC-RAS. Based on the water levels, water surface TIN is created, and flood inundation areas are mapped out using HEC-GeoRAS.

3.2.2 Hydrologic / Hydraulic Boundary

In principle, the water level at river mouth is set at MHWL (Mean Monthly Highest Water Level) of nearby tidal station with reference to the manual of the DPWH. However, if there is the water level adopted in the previous related study, this value is applied. The water level applied in this study is shown in the table below.

Table F.3.4 Water Level at River Mouth River W.L. Reference Data

Ilog-Hilabangan EL. +1.50 m Mean High Water Spring Level with reference to the previous related study

Dungcaan EL. +1.29 m Mean Monthly Highest Water Level of the tidal station “Ormoc Pier, Leyte” with reference to the manual of the DPWH

Meycauayan EL. +0.80 m Mean High Water Spring Level with reference to the previous related study (Water Level at the confluence point with Marilao River is EL. +1.37 m)

Kinanliman EL. +0.72 m Mean High Water Spring Level with reference to the previous related study

Tuganay EL. +0.78 m Mean Higher High Water Level with reference to the previous related study (Water level at the confluence point with Libuganon River is EL. +1.35 m)

Dinanggasan EL. +0.97 m Mean Monthly Highest Water Level of the tidal station “Macabalan Port, Cagayan de Oro” with reference to the manual of the DPWH

3.2.3 Analysis Conditions

(1) Ilog-Hilabangan River Basin Based on the calculation result of the flow capacities, the capabilities of the current river channel are insufficient for the design flood discharges. Therefore, inundation analysis is necessary in order to estimate the inundation area and relating data/information. On the other hand, the inundation analysis was conducted in the previous study using two-dimensional models. Compared the river width and profile prepared in the previous master plan with the new survey results (shown in Figure F.3.2), the river width and riverbed gradient of Ilog River are mostly alike. Based on this, there seems to occur no remarkable channel changes after the previous study. Therefore, it can be judged that there is no considerable differences in inundation area between the previous study and the present conditions. Hence, the results of the analysis done in the previous study are adopted in this Study considering the higher accuracy of the previous analysis.

Figure F.3.2 River Profile of Ilog River

：Averaged riverbed height based on the river cross section survey

：River width based on the river cross section survey

(2) Other Model River Basins Based on the calculation results of the flow capacities, the capabilities of current river channels are insufficient for the design flood discharges. Therefore, inundation analyses are necessary in order to estimate the inundation areas and relevant information. The ranges of the analyses are studied based on the results of the field survey.

3.2.4 Adjustment of SRTM/NASA Data

The geographical feature data for the inundation analysis are SRTM/NASA. Since the altitude data of SRTM/NASA include the error compared with the actual evaluation, height adjustment of SRTM/NASA data is required. For this adjustment, the comparison between SRTM/NASA data and cross section survey data is carried out in order to identify the adjustment values and locations. The results of this adjustment are shown below.

Table F.3.5 Adjustment of SRTM/NASA Data

River Adjusted Value Adjusted SRTM/NASA Data

Dungcaan –2.012 m Built-up Area of Baybay on CR2 Meycauayan –3.970 m CR1～CR6 Kinanliman –3.504 m CR1～CR2 Tuganay –2.150 m Built-up Area of Carmen on CR2

3.2.5 Flood Inundation Area

The flood inundation area of each river basin is described below.

(1) Ilog-Hilabangan River The flood inundation area is set with reference to the previous related study. The area is distributed over the whole low flat ground including the built-up areas of Kabankalan and Ilog, fish pond area and annual crop area. The total inundation area is estimated at 10,402 ha with a 25-year return period flood as shown below. The flood inundation area is shown in Figure F.3.3.

Table F.3.6 Flood Inundation Area of the Ilog-Hilabangan River Basin (Unit:ha)

Flood Scale (Return Period) Land Use 25-year Built-up Area 114.2

Fishpond 2,035.7 Annual Crop 6,710.7

Other 1,541.6 Total 10,402.1

(2) Dungcaan River The flood inundation area consists of mangrove forest at around the river mouth, built-up area of the Baybay City and annual crop area in the upstream of the Bay-bay Bridge. The total inundation area is estimated at 173 ha with a 20-year return period flood as shown in the following table. The flood inundation map is shown in Figure F.3.4.

Table F.3.7 Flood Inundation Area of the Dungcaan River Basin

(Unit:ha) Flood Scale (Return Period) Land Use 20-year

Built-up Area 13.0 Fishpond 0.0

Annual Crop 89.1 Other 70.5 Total 172.6

(3) Meycauayan River Valenzuela, Obando, Meycauayan and Malabon are generally located at very low elevations, therefore, these areas are always under the menace of flood inundation. There are two types of flood in these areas. The one is channel overflow and the other is influence of high tide. Particularly, the flood inundation is remarkable in the downstream portion from the North Luzon Highway. The total inundation area is estimated at 5,222 ha with a 30-year return period flood as shown below. Figure F.3.5 shows the flood inundation area.

Table F.3.8 Flood Inundation Area of the Meycauayan River Basin

(Unit:ha) Flood Scale (Return Period): 30yr

Land Use VOM ImprovementArea Other Total

Built-up Area 804.2 352.8 157.8 1,314.8 Fishpond 741.5 92.0 2,830.7 3,664.2

Annual Crop 56.9 25.2 24.0 106.1 Other 0.0 93.7 42.8 136.5 Total 1,602.6 563.7 3,055.3 5,221.6

Note) The vacant holes nearest to the river channels in inundated area are included in the inundation area considering flood conditions.

(4) Kinanliman River

The water, which flows from the upper stream portion, has afflux at the narrow segment of the Bridge, and the flood is exerted on the built-up area of Real. The total inundation area is estimated at 13 ha with 25-year return period flood as tabulated below. Figure F.3.6 shows the flood inundation area.

Table F.3.9 Flood Inundation Area of the Kinanliman River Baisn (Unit:ha)

Flood Scale (Return Period) Land Use 25-year Built-up Area 8.4

Fishpond 0.0 Annual Crop 0.0

Other 4.2 Total 12.6

(5) Tuganay River The flood inundation area spreads out in the low flat area, which includes the downstream of the Tuganay, Anibongan and Ising Rivers. The inundation area consists of the built-up areas of Carmen and Dujali, fishpond and annual crop areas. The total inundation area is estimated at 7,711 ha with 25-year return period flood as shown in Table F.3.10. Figure F.3.7 shows the flood inundation area.

Table F.3.10 Flood Inundation Area of the Tuganay River Basin

(Unit:ha) Flood Scale (Return Period) Land Use 25-year

Annual Crop 6,857.5 Other 307.4 Total 7,710.6

Note) The vacant holes nearest to the river channels in inundated area are included in the inundation area considering flood conditions.

(6) Dinanggasan River The upper stream from the Bridge is the debris flow section with the riverbed gradient of 1/30 or more. Based on these characteristics, it is considered that the flood damages are mainly caused by sands and rocks with flash flood. Therefore, the damage area is estimated based on the potential area for debris flows shown in the previous study with due consideration of the topography and river conditions. The flood inundation area is roughly estimated as shown in Figure F.3.8. The total inundation area is estimated at around 147 ha as shown below.

Table F.3.11 Flood Inundation Area of the Dinanggasan River Basin

(Unit:ha) Flood Scale (Return Period)Land Use 20-year

Annual Crop 91.5 Other 49.3 Total 146.8

Figure F.3.3 Flood Inundation Area of the Ilog-Hilabangan River Basin

Figure F.3.4 Flood Inundation Area of the Dungcaan River Basin

Estimated Flood Potential Area of the Dungcaan River Basin

Figure F.3.5 Flood Inundation Area of the Meycauayan River Basin

Figure F.3.6 Flood Inundation Area of the Kinanliman River Basin

Estimated Flood Potential Area of the Kinanliman River Basin

Figure F.3.7 Flood Inundation Area of the Tuganay River Basin

Figure F.3.8 Flood Inundation Area of the Dinanggasan River Basin

Estimated Flood Potential Area of the Dinanggasan River Basin

4 PRELIMINARY DESIGN OF MAIN STRUCTURAL MEASURES

4.1 Design Conditions

The design criteria are prepared mainly based on the “Manual on Design of Flood Control Structures, January 2005, DPWH”, “Manual for River Works in Japan, Ministry of Land, Infrastructure and Transport, Japan” and others. The major design concepts are described below.

4.1.1 Channel Alignment

In order to minimize land acquisition, the channel will follow as much as possible the existing river alignment. However, the design alignment of river course should be composed of straight lines or large radius curves in order to provide a smooth flood flow in principle.

4.1.2 Longitudinal Profile and Cross Sections

(1) Design High Water Level Design high water level is set, in principle, to correspond with the average ground elevation along the river course with due consideration of the maximum flood water level.

(2) Design Riverbed Design riverbed profile principally follows the existing average riverbed profile to avoid unbalanced scouring and sedimentation as well as to minimize relocation and modification of existing river structures. Change in riverbed gradients between two reaches is set such that the ratio of riverbed gradients between the upper and lower stretches is less than 1:2 to ensure the stability of the river channel. In addition, the design riverbed should be determined in relation with the average velocity and high water level of river channel, considering dike stability and the flood damage potential in the hinterland of the channel.

(3) Cross Section Cross section is designed conforming to the existing one in order to reduce land acquisition. In the narrow reaches, the river should be widened to confine the design discharge. In this river channel improvement design, the compound cross section type is applied to Ilog-Hilabangan River with large design discharges, and the single cross section type is applied to the other rivers. Regarding the slope of dike and revetment, 1:2.0 side slope is applied for excavation slope, and 1:3.0 side slope is applied for high banking of 4.0 m or more. On the other hand for Meycauayan and Dungcaan Rivers, 1:0.5 side slope revetment or vertical wall is applied according to the land use and housing conditions of the bank line.

4.1.3 Freeboard

Freeboard for embankment corresponding to design discharge is shown in Table F.3.1.

4.1.4 Manning’s Roughness Coefficient for Improved Channel

If there is available figure of roughness coefficient adopted in the previous related study, this coefficient is applied in principle. Otherwise, the coefficient is preliminarily determined according to the plan and O/M condition. The roughness coefficient of each river is shown below.

Table F.4.1 Manning’s Roughness Coefficient River River Channel

Ilog-Hilabangan 0.035 Dungcaan 0.045 Meycauayan 0.030* Kinanliman 0.040* Tuganay 0.040 Dinanggasan 0.040

Note) *: value adopted in the previous related study

4.2 Preliminary Design

4.2.1 Ilog-Hilabangan River

The river channel improvement works will be required for the following stretches of the river in order to attain the flood mitigation against the project scale of 25-year return period. The length and section for the improvement are tabulated in Table F.4.2. On the other hand, longitudinal profile and typical cross sections of the improvement are shown in Fig F-4-1.

Table F.4.2 River Channel Improvement of the Ilog-Hilabangan River Basin Ilog River

Station Number Stretch From To Design Discharge

(m3/s) Length Width (km) (m)

1 0 7.0 3,690 7.0 360 2 7.0 16.0 3,690 9.0 290 3 16.0 20.0 2,920 4.0 220

TOTAL 20.0

Hilabangan River Station Number Stretch From To

Design Discharge (m3/s)

Length Width (km) (m)

1 0 2.0 1,930 2.0 120 TOTAL 2.0

Based on the above design, the basic layout of the main structural measures is presented in Figure F.4.1.

Figure F.4.1 Proposed Works of the Ilog-Hilabangan River Basin

100 150 200 250 300 350 400 450 500

Station (m)

vation (

357.2mEL+6.4m

EL+5.2m

EL-2.9m

5.4km (0～7.0km)

210.0m

250 300 350 400 450 500 550 600 650 700

Station (m)

vation (

250 300 350 400 450 500 550 600 650

Station (m)

vation (

100.0m

17.0km (16.0～20.0km)

220.8mEL+11.0m

EL+9.8m

EL+0.8m

100 150 200 250 300 350 400 450Station (m)

vation (

1.0km (0～2.0km)

EL+13.6m

EL+3.6m

EL+12.6m

120.0m

290.0m

EL+9.4mEL+8.2m

EL-0.6m

12.2km (7.0～16.0km)

160.0m

Optimum Plan

4.2.2 Dungcaan River

The river channel improvement works will be required for the following stretches of the river in order to attain the flood mitigation against the project scale of 20-year return period. The length and section for the improvement are tabulated in Table F.4.3. On the other hand, longitudinal profile and typical cross sections of the improvement are shown in Fig.F-4-2.

Table F.4.3 River Channel Improvement of the Dungcaan River Basin Station Number

Stretch From Design Discharge Length Width

To (m3/s) (km) (m) 1 0 0.2 655 0.2 125 2 0.2 1.4 655 1.2 115 3 1.4 1.6 655 0.2 70 4 1.6 1.8 655 0.2 115

TOTAL 1.8

Figure F.4.2 Proposed Works of the Dungcaan River Basin

0 100 200 300 400 500 600 700 800 900 1000

Station (m)

120.0m

138m(0～200m)

EL+2.5m

EL+1.5m

EL-1.9m

123.9m

0 100 200 300 400 500 600 700 800 900 1000

Station (m)

vation

110.0m

886m(200～1400m)

EL+3.2m

EL+2.2m

EL-1.5m

116.1m

0 100 200 300 400 500 600

Station (m)

1663m(1400～1600m)

EL+4.0m

EL+3.0m

EL-1.2m

Sheet Pile

Optimum Plan

4.2.3 Meycauayan River

The river channel improvement works will be required the following stretches of the river in order to attain the flood mitigation against the project scale of 30-year return period. The length and section for the improvement are tabulated in Table F.4.4. On the other hand, longitudinal profile and typical cross sections of the improvement are shown in Fig.F-4-3 and Fig.F-4-4.

Table F.4.4 River Channel Improvement of the Meycauayan River Basin Meycauayan River

Station Number Stretch From

Design Length Width Remarks Discharge To (m3/s) (km) (m)

1 5.0 9.5 580 4.5 - Embankment Type 2 9.5 11.2 580 1.7 90 Embankment Type 3 11.2 12.2 580 1.0 40 Vertical Wall Type 4 12.2 13.6 320 1.4 50 Embankment Type 5 13.6 14.5 320 0.9 30 Vertical Wall Type

Total 9.5

Marilao River Station Number

Stretch From Design Length Width Remarks Discharge To (m3/s) (km) (m)

1 0.0 0.5 730 0.5 66 Embankment Type 2 0.5 1.0 730 0.5 30 Vertical Wall Type 3 1.0 2.0 730 1.0 50 Vertical Wall Type 4 2.0 3.5 730 1.5 45 Vertical Wall Type 5 3.5 4.5 730 1.0 30 Vertical Wall Type

Total 4.5

The same work items proposed in the pervious F/S are adopted in the structural measures of the Meycauayan River Basin. Based on the above design, the basic layout of the main structural measures is presented in Figure F.4.3.

Figure F.4.3 Proposed Works of the Meycauayan River Basin

Optimum Plan

CR1_Meycauayan

500 600 700 800 900 1000 1100

Station (m)

vation (

EL+2.0mEL+1.0m

5.1km(3.0～5.5km)

CR2_Meycauayan

500 600 700 800 900

Station (m)

EL+2.2mEL+1.2m

8.8km(8.0～9.5km) CR3_Meycauayan

200 300 400 500

Station (m)

9.9km(9.5～11.5km)

EL+2.7mEL+1.7m

EL-3.6m

88.6mCR4_Meycauayan

100 200 300 400

Station (m)

12.0km(11.5～12.5km)

EL-3.1m

EL+3.1EL+3.949.5m

CR5_Meycauanan

300 400 500 600

Station (m)

vation

12.8km(12.5～13.0km)EL+4.2m

EL+3.4m

EL-3.0m

CR1_Marilao

0 100 200 300

Station (m)

vation

0.5km(0～0.5km)

68.2m EL+2.6mEL+1.6m

EL-5.1m

CR2_Marilao

200 300 400 500

Station (m)Ele

vation

1.0km(0.5～1.5km)EL+2.9m

EL+1.9m

EL-4.7m

CR3_Marilao

-50 50 150 250

Station (m)

vation

3.5km(3.0～4.5km)

EL+3.8mEL+4.8m

EL-2.6m

CR5_Meycauayan

300 400 500 600

Station (m)

vation (

13.3km(13.0～14.5km)EL+4.2m

EL+3.4m

EL-3.0m

CR4_Meycauayan

100 200 300 400

Station (m)

vation (

12.8km(12.5～13.0km)

EL-3.1m

EL+3.1EL+3.949.5m

4.2.4 Kinanliman River

(1) River Channel Improvement The river channel improvement works will be required the following stretches of the river in order to attain the flood mitigation against the project scale of 25-year return period. The length and section for the improvement are tabulated in Table F.4.5. On the other hand, longitudinal profile and typical cross sections of the improvement are shown in Fig.F-4-5.

Table F.4.5 River Channel Improvement of the Kinanliman River Basin Station Number Stretch From To

1 0 0.39 380 0.39 55 2 0.39 0.54 380 0.15 155 3 0.54 0.74 380 0.20 115 4 0.74 1.05 380 0.31 45

TOTAL 1.05

(2) Sabo Dam Referring to the previous FCSEC study, the salient features of the sabo dam is summarized, as shown below:

Table F.4.6 Salient Features of Sabo Dam of the Kinanliman River Basin Dimension Design Value

Dam Type Permeable Type Dam Storage Capacity (Thousand m3) 16.2 Dam Height (m) 5.5 Dam Width (m) 85.0

Figure F.4.4 Proposed Works of the Kinanliman River Basin

4.2.5 Tuganay River

(1) River Channel Improvement The river channel improvement works will be required for the following stretches of the river in order to attain the flood mitigation against the project scale of 25-year return period. The length and section for the improvement are tabulated in Table F.4.7. On the other hand, longitudinal profile and typical cross sections of the improvement are shown in Figs. F-4-6 to F-4-8.

Table F.4.7 River Channel Improvement of the Tuganay River Basin Tuganay River

Station Number Stretch From To Design Discharge

(m3/s) Length Width (km) (m)

1 0 9.0 340 - 350 9.0 60 2 9.0 15.0 220 6.0 60 3 15.0 21.0 270 - 340 6.0 55

TOTAL 21.0

Anibongan River Station Number Stretch From To

1 0 6.5 190 6.5 65 2 6.5 10.0 190 3.5 60

TOTAL 10.0

JICA CTI Engineering International Co., Ltd.

430 450 470 490 510 530 550

Station (m)

vation

EL+0.8m

EL+3.9m

-179m (-385～-150m)

EL+4.7m

-60 -40 -20 0 20 40Station (m)

-20m (-150～0m)

EL+1.7m

EL+4.4mEL+5.2m

-50 -30 -10 10 30 50 70 90Station (m)

EL+3.0m

EL+7.7m

EL+8.5m

103m (0～150m)

125.0m

360 380 400 420 440 460 480 500

Station (m)

vation

EL+6.1m

EL+9.2mEL+10.0m

302m (150～350m)

160.0m

-50 -30 -10 10 30 50 70 90

Station (m)

vation

582m (350～660m)

EL+15.1mEL+14.3m

EL+10.7m

New Ising River Station Number Stretch From To

1 0 6.0 90 - 130 6.0 100 2 6.0 9.0 90 3.0 50

TOTAL 9.0

Old Ising River Station Number Stretch From To

1 0 3.0 40 3.0 25 TOTAL 3.0

(2) Retarding Basins The retarding basins are planned for the Tuganay and New Ising Rivers. With the design discharge of 25-year return period, the regulation functions are examined to estimate the required capacities of the retarding basins. As a result, the required volumes and dike heights are preliminarily designed as shown below.

Table F.4.8 Dimension of Retarding Basins in the Tuganay River Basin Dimensions Tuganay River New Ising River

Area of Retarding Basin (ha) 200 75 Storage Volume (MCM) 5.00 1.50 Required Capacity (MCM) 4.99 1.42 Surface Elevation (EL. m) 7.6 6.0 Dike Height (m) 3.1 2.3 Dike Length (m) 11,000 4,100

Figure F.4.5 Proposed Works of the Tuganay River Basin

4.2.6 Dinanggasan River

(1) River Channel Improvement The river channel improvement works will be required for the following stretches of the river in order to attain the flood mitigation against the project scale of 20-year return period. The length and section for the improvement are tabulated in Table F.4.9. On the other hand, longitudinal profile and typical cross sections of the improvement are shown in Fig.F-4-9.

CR1_Tuganay

200 250 300 350 400 450 500 550 600

Station (m)

vation (

EL+5.1m

EL-2.8m

6.4km(0～6.5km)

CR2_Tuganay

150 200 250 300 350 400 450 500

Station (m)

8.8km(6.5～9.0km)

EL+5.8m

EL-1.9m

EL+6.6m

CR3_Tuganay

150 200 250 300 350Station (m)

vation

14.6km(9.0～15.0km)

EL+7.6m

59.0m EL+8.4m

EL+1.9m

CR4_Tuganay

100 150 200 250Station (m)

vation (

16.2km(15.0～17.0km)

EL+3.7m

EL+9.1mEL+9.9m

CR5_Tuganay

50 100 150 200Station (m)

vation (

18.8km(17.0～21.0km)

EL+12.2m

EL+7.0m

EL+13.0m56.0m

CR1_Anibongan

200 250 300 350 400

Station (m)

vation

4.3km(0～4.5km)

EL+6.4m

66.2mEL+7.0m

EL-0.7m

CR2_Anibongan

300 350 400 450 500

Station (m)

vation (

6.1km(4.5～6.5km)

EL+6.6m

65.0m EL+7.2m

EL-0.3m

CR3_Anibongan

150 200 250 300 350

Station (m)

vation

9.8km(6.5～10.0km)

EL+7.0m

58.4m EL+7.6m

EL+1.2m

CR1_Ising

-50 0 50 100 150

Station (m)

vation (

EL+1.4m

99.0mEL+2.0m

EL-4.0m

(0～2.0km)

CR2_Ising

0 50 100 150

Station (m)

vation

6.0km(2.0～6.0km)

EL+4.0mEL+3.4m

EL-1.0m

100.0m

CR3_Ising

3,400 3,450 3,500 3,550

Station (m)

vation

(6.0～9.0km)

EL+4.2mEL+3.6m

EL-0.5m

CR_Old Ising

50 100 150

Station (m)

vation

3.0km(0～3.0km)

EL+3.5mEL+4.1m

EL-0.3m

Optimum Plan

Table F.4.9 River Channel Improvement for the Dinanggasan River Basin Station Number Stretch From To

1 0 0.12 296 0.12 215 2 0.12 0.53 296 0.41 260 3 0.53 0.88 296 0.35 215 4 0.88 1.40 296 0.52 80

TOTAL 1.40* *: In addition to the above, training dike of 0.2km is planned for the right bank.

(2) Sand Pocket and Sabo Dam One (1) sabo dam and one (1) sand pocket are preliminary proposed in this plan. The main purpose of these sabo facilities is to catch the front of debris flow, the most dangerous portion of debris flow, in order to weaken its destructive power. The salient features of the planned sabo facilities are shown below.

Table F.4.10 Salient Features of the Sabo Facilities of the Dinanggasan River Basin Dimension Sabo Dam Sand Pocket

Dam Type Impermeable Type Dam Storage Capacity (Thousand m3) 19.1 6.4 Dam Height (m) 8.0 5.5 Dam Width (m) 72.5 30.0

Figure F.4.6 Proposed Works of the Dinanggasan River Basin

100 200 300 400 500

Station (m)

vation (

120m (0～120m)

EL+4.3mEL+5.1m

EL+3.1m

190.0m

197.8m

200 300 400 500 600Station (m)

vation(m

530m (120～530m)

EL+12.8mEL+11.9m

EL+13.6m

100.0m

107.0m

50 150 250 350 450Station (m)

vation (

880m (530～880m)

EL+26.8mEL+27.6m

EL+25.7m

100.0m

107.6m

0 100 200 300 400Station (m)

1170m (880～1400m)

EL+38.4mEL+39.2m

EL+37.2m

Dinanggasan River Improvement

F - F - 1

Fig. F-4-1

Ilog River Profile

0 2,000 4,000 6,000 8,000 10,000 12,000 14,000 16,000 18,000 20,000 22,000

Station (m)

Elevation

Design W.L.

Design Bank Crest

Design River Bed

Average River Bed

Current Bank Crest (Left)

Current Bank Crest (Right)

Calculated W.L.

1/2,500

Design W.L.

Design Bank Level

1/5,000 1/3,000 1/2,500

Design R.B.Design Riverbed

250 300 350 400 450 500 550 600 650 700

Station (m)

vation (

160.0m

290.0m

EL+9.4mEL+8.2m

EL-0.6m

12.2km (7.0～16.0km)

THE STUDY ON THE NATIONWIDE FLOOD RISK ASSESSMENT AND THE FLOOD MITIGATION

PLAN FOR THE SELECTED AREAS IN THE REPUBLIC OF THE PHILIPPINES

JAPAN INTERNATIONAL COOPERATION AGENCY

Longitudinal Profile and Typical Cross Sections of Ilog-Hilabangan River

250 300 350 400 450 500 550 600 650

Station (m)

vation (

17.0km (16.0～20.0km)

100.0m

220.8mEL+11.0m

EL+9.8m

EL+0.8m

F - F - 2

Fig.F-4-2 THE STUDY ON THE NATIONWIDE FLOOD RISK ASSESSMENT AND THE FLOOD MITIGATION

Longitudinal Profile and Typical Cross Sections of Dungcaan River

Dungcaan River Profile

0 500 1,000 1,500 2,000 2,500 3,000 3,500 4,000 4,500 5,000

Station (m)

vation

Existing River Bed

Current Water Level

Calculated Water Level

1/1,000

1/2,000 1/800

Design W.L.

Design Bank Level

0 100 200 300 400 500 600 700 800 900 1000

Station (m)

vation

120.0m

138m(0～200m)

EL+2.5m

EL+1.5m

EL-1.9m

123.9m

0 100 200 300 400 500 600 700 800 900 1000

Station (m)

vation (

110.0m

886m(200～1400m)

EL+3.2m

EL+2.2m

EL-1.5m

116.1m

F - F - 3

Fig. F-4-3 THE STUDY ON THE NATIONWIDE FLOOD RISK ASSESSMENT AND THE FLOOD MITIGATION

Longitudinal Profile and Typical Cross Sections of Meycauayan River

Meycauayan River Profile

0 2,000 4,000 6,000 8,000 10,000 12,000 14,000 16,000

Station (m)

vation (

Design River Bed

Average River Bed

Calculated W.L.

Design W.L.

Design Bank Crest

Design W.L.Design Bank Level

1/5,200

CR1_Meycauayan

200 300 400 500

Station (m)

vation (

9.9km(9.5～11.5km)

EL+2.7mEL+1.7m

EL-3.6m

CR2_Meycauayan

300 400 500 600

Station (m)

vation

13.3km(13.0～14.5km)EL+4.2m

EL+3.4m

EL-3.0m

F - F - 4

Longitudinal Profile and Typical Cross Sections of Marilao River

Marilao River Profile

0 1,000 2,000 3,000 4,000 5,000

Station (m)

vation (

Design W.L.

Design Bank Crest

Design River Bed

Average River Bed

Calculated W.L.1/1,200

Design W.L.Design Bank Level

CR1_Marilao

200 300 400 500

Station (m)

1.0km(0.5～1.5km)EL+2.9m

EL+1.9m

EL-4.7m

CR2_Marilao

-50 50 150 250

Station (m)

vation (

3.5km(3.0～4.5km)

EL+3.8mEL+4.8m

EL-2.6m

F - F - 5

Longitudinal Profile and Typical Cross Sections of Kinanliman River

Kinanliman River Profile

-400 -200 0 200 400 600

Station (m)

vation (

Design W.L.

Design Bank Crest

Deepest River Bed

Design River Bed

Calculated W.L.

Spur Dike, H=2m, L=5m

Dredge Width B=30m

Design W.L.

Design R.B.

Design Bank Level

Design Riverbed

-60 -40 -20 0 20 40Station (m)

vation

-20m (-150～0m)

EL+1.7m

EL+4.4mEL+5.2m

-50 -30 -10 10 30 50 70 90Station (m)

vation (

EL+3.0m

EL+7.7m

EL+8.5m

103m (0～150m)

125.0m

F - F - 6

Fig. F-4-6

Tuganay River Profile

0 5,000 10,000 15,000 20,000 25,000

Station (m)

Design W.L.

Design Bank Crest

Design River Bed

Average River Bed

Current Bank Crest(Left)

Current Bank Crest(Right)

Calculated W.L.

Design W.L.

Design Bank Level

esign R.B.Design Riverbed

Longitudinal Profile and Typical Cross Sections of Tuganay River

CR1_Tuganay

200 250 300 350 400 450 500 550 600

Station (m)

vation

EL+5.1m

EL-2.8m

6.4km(0～6.5km)

CR2_Tuganay

150 200 250 300 350Station (m)

vation

14.6km(9.0～15.0km)

EL+7.6m

59.0m EL+8.4m

EL+1.9m

1/1,500 1/8001/5,000 1/2,500

F - F - 7

Longitudinal Profile and Typical Cross Section of Anibongan River

Anibongan River Profile

0 2,000 4,000 6,000 8,000 10,000 12,000

Station (m)

vation

Design W.L.

Design Bank CrestDesign River Bed

Average River Bed

Current Bank Crest (Right)Calculated W.L.

Design Bank Level

Design W.L.

1/5,000 1/2,500

CR_Anibongan

200 250 300 350 400

Station (m)

4.3km(0～4.5km)

EL+6.4m

66.2mEL+7.0m

EL-0.7m

F - F - 8

Fig. F-4-8

Ising River Profile

0 2,000 4,000 6,000 8,000 10,000

Station (m)

vation (

Design W.L.

Design Bank CrestDesign River Bed

Average River Bed

Current Bank Crest (Right)Calculated W.L.

1/2,000

Design Bank LevelDesign W.L.

CR_Ising

0 50 100 150

Station (m)

vation (

6.0km(2.0～6.0km)

EL+4.0mEL+3.4m

EL-1.0m

100.0m

Old Ising

0 1,000 2,000 3,000 4,000 5,000

Station (m)

vation (

Design W.L.

Longitudinal Profile and Typical Cross Sections of Ising River

CR_Old Ising

50 100 150

Station (m)

vation (

3.0km(0～3.0km)

EL+3.5mEL+4.1m

EL-0.3m

Design Bank Crest

Design River Bed

Average River Bed

Calculated W.L.

Design Bank Level

Design W.L.

1/2,000

F - F - 9

Fig. F-4-9

Dinanggasan River Profile

0 200 400 600 800 1000 1200 1400

Station (m)

vation

Design W.L.

Design Bank Crest

Design River Bed

Deepest River Bed

Current Bank Crest(Left)

Current Bank Crest(Right)

Calculated W.L.

Average River Bed

1/45 1/25

Design W.L.

Design Bank Level Design R.B.Design Riverbed

100 200 300 400 500

Station (m)

vation

120m(0～120m)

EL+4.3mEL+5.1m

EL+3.1m

190.0m

197.8m

Longitudinal Profile and Typical Cross Sections of Dinanggasan River

200 300 400 500 600Station (m)

530m(120～530m)

EL+12.8mEL+11.9m

EL+13.6m

100.0m

107.0m

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