Dredging Volume Analysis using Multi Beam Echo Sounder Data

Khomsin

, Eko Yuli Handoko

, Danar Guruh Pratomo

and Irfan Maulana Yusuf

Geomatics Engineering Department, Institut Teknologi Sepuluh Nopember, Surabaya, Indonesia

Keywords: SWAC, MBES, cross section, volume, dredging

Abstract: The Tanjung Perak port passed through by Surabaya West Access Channel (SWAC) has an important role

as driving of economic growth in the field of sea transport. The rivers that flow to SWAC has bringing large

of sediments that caused of shallow on that area, so that influence the effectiveness of SWAC. Hence

maintenance dredging port water is needed to maintain the ideal depth. This research will conduct the

calculation of dredging volume with data derived from Multi Beam Echo Sounder (MBES) survey in

SWAC using Hypack and AutoCAD Civil 3D software. The results of each software will be analysed to see

which software will be used in doing dredging in the sea correctly. The volume calculation method used is

cross section method (average end area). The MBES data processing produces bathymetry map that

indicates the study location with depth less than -13 meter with along channel 17.6 km. Total value volume

obtained from calculation AutoCAD Civil 3D is 5,921,745 m³ and Hypack is 5,952,881.83 m³. These values

compared to the composite method, the volume difference of Autodesk Civil 3D is only 0.67% and Hypack

is 1.2%. Because of the small difference (0.5%), it means that the Autodesk Civil 3D and Hypack software

have the same volume dredging at SWAC.

1 INTRODUCTION

Referring to United Nations Convention on the Law

of the Sea (UNCLOS) 1983, Indonesia is one of the

biggest archipelagic country in the world (Windari,

2009). This is because Indonesia has 17,504 islands

and 15,056 islands that have been registered in the

United Nations and the ratio between its land and

ocean in Indonesia is 1:2 (UN, 2017). Therefore sea

plays an important role in Indonesian economic

activities. The sea has a role as communication lane

means that the use of the sea for the traffic interest

of inter-island, inter-country and inter-continental

shipping traffic, both for passengers and goods

transportation.

Surabaya is the second largest city after Jakarta

in Indonesia. Therefore, the economic activities in

East Java and Eastern Indonesia through the

Surabaya port, namely Tanjung Perak Port. Tanjung

Perak Port is the second largest port after Tanjung

Priok in Jakarta. Tanjung Perak Port has a strategic

role to support the traffic activities of sea

transportation and as a driver of economic growth in

East Java and the Eastern Indonesia.

Determination of shipping channels in terms of

navigational security aspects is intended to prevent

channel from sinking during low elevation tides,

growing shallows or corals, and unsafe depth of

seabed to draft ships. Other than that the straits are

too narrow, waters that have currents or waves that

make it difficult for boat movements and other

navigation barriers (Parwata, 2011). Because of the

large port, many large ships with drafts of more than

10 m enter the Tanjung Perak port. For example, the

North Jamrud port is one of the busiest of quay in

the Tanjung Perak port. Recorded in 2011 there were

14,117 ships anchored in North Jamrud, while in

2012 it increased to 14,773 ships (Buana, 2014). It

had to go through the Surabaya West Access

Channel (SWAC) before entering to port.

Rivers that lead to the SWAC carry a large

amount of sediment which results in siltation, which

can affect the effectiveness of the SWAC (Wahyuni,

et al., 2013). To solve the sedimentation problem

and maintain service quality, it is necessary to pay

attention to the condition of the shipping channel as

the ship's entrance to the port area and the direction

of the ship entering the port waters.

The depth of the shipping path that is not in

accordance with the draft of the ship can cause the

ship to run aground and endanger the safety of

shipping. Therefore, it is necessary to carry out port

Khomsin, ., Handoko, E., Pratomo, D. and Yusuf, I.

Dredging Volume Analysis using Multi Beam Echo Sounder Data.

DOI: 10.5220/0008550500270031

In Proceedings of the 3rd International Conference on Marine Technology (SENTA 2018), pages 27-31

ISBN: 978-989-758-436-7

dredging maintenance to maintain the ideal depth

according to the dimensions and size of the vessel.

This study will calculate the volume of dredging

with data from the multibeam echosounder survey in

the SWAC using Hypack and AutoCAD Civil 3D

software. Then their volume compared each other

and where is suitable for use in the dredging work at

sea.

2 METHOD

2.1 Data and Research Area

The research location area is in the Surabaya West

Access Channel – Tanjung Perak Port, Surabaya,

which is geographically located between 6˚50'00 " S

- 7˚00'00" S and 112˚40'00 " E - 112˚45'00" E. This

location can be seen in the Figure 1 below.

Figure 1: Research location (Disnav, 2016).

The data used in this research is the ASCII Multi

Beam Echo Sounder (MBES) (Figure 2) data in

Surabaya West Access Channel (SWAC) in June

2017 obtained from the Dinas Navigation Surabaya,

East Java, Indonesia.

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Figure 2: Spot depth of MBES data.

2.2 Method

The first step is to determine the boundary area to be

calculated by dredging volume provided the depth is

less than -13 meters. After that volume calculation

manually used the cross section and composite

method which will be used as a reference volume

(true volume) as a comparison of the volume

calculation results from the AutoCAD Civil 3D and

Hypack software. Then the ASCII Multi Beam Echo

Sounder data are plotted to the layout drawing. The

next step is to form 3-Dimensional model using the

principle of Triangular Irregular Network (TIN) to

obtain a Digital Terrain Model (DTM) surface

(Figure 3 and Figure 4).

Figure 3: Triangular Irregular Network in SWAC

(Autodesk, 21014).

SENTA 2018 - The 3rd International Conference on Marine Technology

Figure 4: An example of 3-D Model at one cross station.

This surface will be used as a reference in

calculating the dredging volume. The design of

dredging is formed in each software with the same

design specifications which has a slope of 1:5

(Figure 5).

Figure 5: Template section as depth referenced (design

surface of dredging) (Hypack, 2016).

Then, a cross section should be formed in each

50 m and calculate volume between one section and

another section using Average End Area. Finally,

analysed the volume obtained from AutoCad Civil

3D and Hypack software.

3 RESULT AND DISCUSSION

3.1 SWAC Bathymetric Map

The SWAC bathymetric map formed from MBES

data shows that the shallowest depth is -4 m and the

deepest depth is -13 m. This map (Figure 6) shows

that the waters around this SWAC are quite shallow.

Therefore, to avoid ships entering the Tanjung Perak

port through SWAC, routine maintenance of the

SWAC is required by dredging the sedimentation

that occurs.

Figure 6: Disnav SWAC Bathymetric Map modification.

3.2 Volume Calculation as Referenced

by Composite and Cross Section

Manually Method

In this case, the volumes are used as references to

compare the volume between the Autodesk Civil 3D

and Hypack software are composite method and

cross section method manually. Composite method

is based on surface 3D models which derived from

Triangulated Irregular Network (TIN) with two

surfaces namely base surface (design surface) and

existing surface (Labant, et al., 2013). The

composite method can be seen in Fugure 7 and the

formula can be seen in equation 1.

Figure 7. Illustration of Triangular Irregular Network

(Labant, 2013).





PV (1)

where V is volume, Hi is elevation and P is area of

triangle prism.

While cross section method manually it means

that calculate volume between a station and another

station consequentially (Figure 7). Figure 8

illustrates the concept of computing volumes by the

average-end area method (cross section method). In

the figure, A1 and A2 are end areas at two stations

Dredging Volume Analysis using Multi Beam Echo Sounder Data

separated by a horizontal distance L. The volume

between the two stations is equal to the average of

the end areas multiplied by the horizontal distance L

between them (see Equation 2) (Ghilani & Wolf,

2012).

Figure 8: Cross section of volume illustrating (Ghilani,

2012).

)(





 (2)

where V

is volume, A

and A

are end area, L is

distance between A

and A

The result of the volume calculation with the

composite method is 5,881,819.17 m

and the cross

section is 5,370,694.656 m

. The dredging volume

difference between cross section manually and

composite method is -511,124.514 m

(-8.7%).

3.3 Volume Calculation by Cross

Section Method using Autodesk

Civil 3D Software

In calculating the dredging volume in the AutoCAD

Civil 3D software, two surfaces are needed, namely

existing and design surface. The first surface is an

existing surface containing the x, y, z coordinates of

the dredging bathymetry at the SWAC. Based on the

Indonesian Minister of Transportation regulation

No. 455 year 2016, the minimum depth of SWAC is

-13 m and the wide of SWAC is 150 m.

Figure 9: Cross section STA 0+100 in AutoCad Civil 3D.

The method used to calculate volume using

AutoCad Civil 3D is a cross section with interval 50

m. There are 353 cross sections in this case. Figure 9

is one example of cross section at the station STA 0

+ 100.00. The smallest volume value is 35.1 m³

which located in section between STA 17 + 550.00

and STA 17 + 626.77. This is because the depth in

this section approach -13 meters. Conversely the

largest volume is 34,802.02 m

which located in

section between STA 12 + 100 and STA 12 + 150.

This section is quite shallow, so that the existing

surface above the dredge design should be cut quite

a lot. The total volume from 353 cross section in this

case is 5,921,745 m

The volume difference between the Autodesk

Civil 3D cross section method and the composite

method is 39,925.83 m

(0.67%), whereas the

volume difference between the Autodesk Civil 3D

cross section method and the cross section manually

method is 551,050.344 m

(10.26%).

3.4 Volume Calculation by Cross

Section Method using Hypack

Software

The existing surface modelled by TIN will be

overlaid with a dredge template (Figure 10) to

calculate its volume. The size of the dredge template

refers to Minister Transportation regulation No. 455

in 2016.

Figure 10: Template section as depth referenced.

The following Figure 11 is a side view of one

section. Information on the value of the volume of

each section displayed is divided into three, namely

VL (Volume Left), V1 (Channel), and VR (Volume

Right). Volume Left is the volume that is in the left

slope area, as well as Volume Right is the volume

that is in the right slope area, while V1 is the volume

a channel besides the slope area in the first layer.

SENTA 2018 - The 3rd International Conference on Marine Technology

Figure 11: Cross section STA 0 + 100 in HyPack

Software.

From the calculation of volume using Hypack

sofware, the smallest volume value of 127.23 m³ is

located in section between STA 17 + 550 + STA 17

+ 626.77. The small value is due to the depth of the

section approaching -13 meters, the existing surface

above the dredge design is small. Conversely the

largest volume value is 32.002,69 m³ which located

in section between STA 12 + 100 and STA 12 +

150. This is because the shallow depth in the section,

the existing surface above the dredge design is quite

a lot to be cut.

Table 1: Volume of SWAC using Hypack.

Design Volume (m

)

VL (Volume Left) 839,934.84

V1 (Channel) 4,525,591.71

VR (Volume Right) 46,184.21

Total 5,952,881.83

In calculating the volume of cross section with

Hypack software the results of the calculation

information displayed are divided into three parts,

namely the volume value in VL, V1, and VR. The

total volume of SWAC with the cross section

method using Hypack is 5,952,881.83 m

The volume difference between the Hypack cross

section method and the composite method is

71,062.66 m

(1.2%), whereas the volume difference

between the Hypack cross section method and the

manual cross section method is 582,187.174m

(9.77%).

4. CONCLUSION

Conclusions that can be drawn from this study are as

follows :

1. The volume difference between the

composite method and the manual cross

section method used as a reference to

the comparison calculation is very

significant at 8.7% (511,124.514 m

)

2. Difference between volume calculation

using Autodesk Civil 3D and Hypack

software is equal to 31,136.83 (0.52%)

The volume of Autodesk Civil 3D and Hypack

results have almost the same value as the composite

method with the difference 0.67% and 1.2%

consecutively and compared with manual cross

section are 10.26% for Autodesk Civil 3D and

9.77% for Hypack software.

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Dredging Volume Analysis using Multi Beam Echo Sounder Data