Variability of Volume Computation of Dredged

Material in Association with Single Beam Line Survey

Directions and Dredger’s Type

(NEW SUEZ CANAL PROJECT)

Prepared By:

Eng\ Essam Ali Gouda Prf.Dr. Saad Mesbah Dr. Mohamed Mohasseb

Presentation Outline

Introduction

Theoretical Framework

Data Collection

Data Processing & Analysis

Conclusion

INTRODUCTION

INTRODUCTION

The Suez Canal is an artificial sea-level

waterway in Egypt, connecting the

Mediterranean Sea to the Red Sea

through the Isthmus of Suez, and

separates the African continent from

Asia. It extends 193.30 km from the

northern terminus of Port Said to the

southern terminus of Port Tewfik at the

city of Suez. The canal width (theoretical

-11 m level) is in a range between 205 to

255 m (as shows in Figure 1). The canal

depth is 23-24 m which allows passage of

ships up to 20 m (66 feet) draft and

240,000 deadweight tons.

INTRODUCTION

Suez Canal Authority (S.C.A) intended to develop it's canal by doubling

the bypass from Km 50 To Km 122 to enable ships with a draft of 66 feet

to transit freely in two directions at the same time.

The Project comprises of:

• Excavating a new canal between Km 58.200 and Km 92.600.

• Widening and deepening the west branches of Balah ,Devresoir

,Bitter lake and kabrit.

INTRODUCTION

The dredging works require dredging with different Cutter Suction

Dredgers (CSD) and different Trailing Suction Hopper Dredgers (TSHD).

Those dredging vessels pumped onshore and/or dumped in the different

allocated dumping areas located in the Great Bitter Lake.

Cutter Suction Dredger “AMAZONE" Trailing Suction Hopper Dredger “BREYDEL”

INTRODUCTION

Either Single beam technique “cross lines & longitudinal lines” and Multi

beam techniques were used during the follow-up implementation of the

NEW SUEZ CANAL PROJECT to reach the design depth by operation of

Trailing Suction Hopper Dredger (TSHD) and Cutter Suction Dredger

(CSD).

Single beam technique with its coverage Multibeam technique with its coverage

Theoretical Framework

Theoretical Framework

Dredger Type

Site & Operation Dredging Operation for the Area

CSD TSHD

Bathymetric

SurveyMulti-Beam Multi-BeamSingle-Beam Single-Beam

Vol.

Calculation

Based on

Long.

Lines Data

Cross

Lines Data

Long.

Lines DataReference Reference

Compute

the

Difference

Is It

Significant?????

Is It

Significant?????

Cross

Lines Data

Data Collection

Data Collection

1. Single-beam:

A single beam echo sounder typeOdom Echotrac MKIII highfrequency 210 kHz was used withdata acquisition systemHYPACK software package. Twotypes of planned lines weresurveyed, cross-line every 500 mand longitudinal line every 50m.For both Dredged Areas CSDdredged area and TSHD dredgedarea.

Overview for Single-beam Survey

Data Collection

2. Multi-beam:

To achieve whole area coverage, the

multi beam lines sailed with

sufficient overlap and at a speed that

allows proper data collection by

using RESON 8125 multi-beam echo

Souder with data acquisition system

QINSY software package For both

Dredged Areas CSD dredged area

and TSHD dredged area.

Overview for Multi-beam Survey

Data Processing &

AnALYSIS

Data Processing & Analysis

All collected data either single-beam data ormulti-beam data were processed includingapply the tide correction by using HYPACKfor single-beam data and QINSY for multi-beam data.

In purpose of volume computation the TINmodels were created based on Single-beamcross lines data, single-beam longitudinal linesdata and multi-beam data, in order to comparethe data, two data sets were selected to eachtype of dredgers. A borders created to be usedby HYPACK as a sample.

The volumes computed inside the bordersbased on the TIN models data with referenceto Zero level for each dredger type.

Also for single-beam data sets Cross-Checksub-program was run into HYPACK tocompute the difference between the Single-beam Data at intersection points for both typedredger working areas.

Data Processing & Analysis

1. Cutter Suction Dredger (CSD)

The two data sets were collected in lastthird of March 2015 and last third ofApril 2015. a border was created as asample of the CSD dredged areas forboth data sets.

Volume calculated inside the borders inCSD dredged areas related to (0.00)level using the cross line survey data,longitudinal line survey data andmultibeam survey data as a reference.

A comparison was held between thecomputed volumes based on the multi-beam data set as a reference and the twosingle-beam data sets ( cross lines-longitudinal lines) for each data setsseparately.

The Figure shows the result of thecomparison, Mar.2015 and Apr.2015

527

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521

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523

273

250

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400

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500

550

15-مارس 15-أبريل

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SURVEY DATE

VOLUME COMPUTATION FOR

CSD

(m3)Multibeam Single-Beam Single-Beam

Border Created for CSD calculation

Data Processing & Analysis

Multibeam

(m) Cross LinesLongitudinal

LinesCross Lines

Longitudinal

Lines

(m) (m) (m) (m)

Mar-15 21.86 21.59 21.69 0.27 0.17 0.10

Apr-15 22.64 22.84 22.49 0.20 0.15 0.35

Absolut Difference

between single-Beam and

multibeamSingle-Beam

Absolut

Difference

in single-

Beam

(m)

Mean Depth

(m)

Date

Data Processing & Analysis

A statistical analysis was carried

out between the single-beam cross

lines and single-beam longitudinal

lines by Cross-Check sub-program

in HYPACK. Figure shown the

Standard deviation and mean of

absolute values for both data sets

Mar. 2015 and Apr. 2015.

The Figure shows the result of

both mean of absolute values for

difference between single-beam

cross lines and single-beam

longitudinal lines at intersection

points, it is clear that the values for

both data sets is less than 10 cm.

0.14

0.07

0.05

0.04

0 0.05 0.1 0.15 0.2

Standard deviation (m)

mean of absolute values (m)

STATISTICAL ANALYSIS FOR

CSD

Apr-15 Mar-15

Data Processing & Analysis

2.Trilling Suction Hopper Dredger(TSHD)

The two data sets were collected in lastthird of March 2015 and last third ofApril 2015. a border was created as asample of the TSHD dredged areas forboth data sets.

Volume calculated inside the borders inTSHD dredged areas related to (0.00)level using the cross line survey data,longitudinal line survey data andmultibeam survey data as a reference.

A comparison was held between thecomputed volumes based on the multi-beam data set as a reference and the twosingle-beam data sets ( cross lines-longitudinal lines) for each data setsseparately.

The Figure shows the result of thecomparison, Mar.2015 and Apr.2015

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SURVEY DATE

VOLUME COMPUTATION FOR

TSHD

(m3)Multibeam Single-Beam Single-Beam

Border Created for TSHD calculation

Data Processing & Analysis

Multibeam

(m) Cross LinesLongitudinal

LinesCross Lines

Longitudinal

Lines

(m) (m) (m) (m)

Mar-15 22.98 22.32 20.97 0.67 2.01 1.35

Apr-15 22.19 20.45 19.08 1.74 3.11 1.37

Absolut Difference

between single-Beam and

multibeam

Absolut

Difference

in single-

Beam

(m)

Single-Beam

Mean Depth

(m)

Date

Data Processing & Analysis

A statistical analysis was carried

out between the single-beam cross

lines and single-beam longitudinal

lines by Cross-Check sub-program

in HYPACK. Figure shown the

Standard deviation and mean of

absolute values for both data sets

Mar. 2015 and Apr. 2015.

The Figure shows the result of

both mean of absolute values for

difference between single-beam

cross lines and single-beam

longitudinal lines at intersection

points, it is clear that the values for

both data sets about 25 cm.

0.31

0.25

0.30

0.23

0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4

Standard deviation (m)

mean of absolute values (m)

STATISTICAL ANALYSIS FOR

TSHD

Apr-15 Mar-15

Conclusion

Conclusion

When single beam survey is used to follow up

the CSD, the survey direction either cross lines

or longitudinal lines will give a good

representation for the dredging area, and will not

affect a tangible impact in the results and the

volume calculation.

The usage of single beam survey to follow up

the TSHD as a cross lines is preferable to have a

good representation for the dredging area and

also for volume calculate even the spacing

between these cross line is so far.

It is not preferable to use longitudinal lines when

single beam survey is carried out for following

up the TSHD because it give inaccurate

representation for the dredging area and

therefore the volume calculation even the

spacing between these longitudinal line is

slightly close.