Zoning of Gas Pipeline Environmental Risk Assessment in Various Land Unit, Maryam KHALEGHIAN

6th
International Disaster and Risk Conference IDRC 2016
‘Integrative Risk Management – Towards Resilient Cities‘ • 28 Aug – 1 Sept 2016 • Davos • Switzerland
www.grforum.org
Zoning of gas pipeline environmental
risk assessment in various land unit
Maryam Khaleghian, Afshin Danekar , Nasim Shalamzari
PhD student of Environment, Dept of environment and Energy, Islamic Azad university
Iran
28 Aug – 1 Sept 2016
Davos
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Circumstance of natural gas
• natural gas consumption
• growing demand
• cleaner energy and environmental concerns
• large worldwide pipeline network
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Impacts of Gas pipeline
• some environmental damages
• digging trenches for laying the pipes
• jungle habitats
• increases of soil erosion
• changes in chemical characteristics of soil layers
• changes in vegetation distributions
• invasion of nonnative species .
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Risk assessment
ninth gas transmission pipeline
supply the required gas energy in west and northwest parts of
the Iran. The pipeline starts from a place with coordination of
48°: 59':46˝E and 31°: 15':13˝E in southeast at the elevation
of 1500 m and will ends in a place with coordination of
46°: 13':30˝E and 36°: 02':53˝E at the elevation of 1300 m The
pipeline with diameter of 56 inch .
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Land unit
200 m distance from each side of the pipeline been considered as a
potential area under the direct impact.
land units were identified by overlaying of three different slopes class
(3class), elevation class (3class) and direction class (5 classes) maps
in which the most and the least environmentally stable units were
determined.
3land units were chosen for assessments.
land unit (1):
This unit with total area of 18122.15 ha was plotted by overlaying the
following map classes for analyzing different level of riskability.
• Elevation class less than 1000 m; slope class less than 15% with all directions
• Elevation class less than 1000 m; slope class 15-30% with direction toward
plateau
• Elevation class less than 1000 m; slope class 30-100% with direction toward P
• Elevation class 1000-1500 m; slope class 0-15% with direction toward P
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Land unit (2):
This unit with total area of 46904/62 ha was plotted by overlaying the following map
classes for analyzing different level of riskability
Elevation class less 1000-1500 m; slope class 15-30 with all directions
Elevation class less than 1000 m; slope class 15-30% with direction toward north, east, south and west
Elevation class 1000-1500 m; slope class less than 15% with direction toward north and east
Elevation class 1500-2000 m; slope class 0-15% with direction toward P, north and east
Land unit (3):
This unit with total area of 45152/67 ha was plotted by overlaying the following map
classes for analyzing different level of riskability:
Elevation class 1500-2000 m; slope class 30-100% with direction toward north, east, south and west
Elevation class less than 1000 m; slope class 30-100% with direction toward south and west
Elevation class 1000-1500 m; slope class less than 15% with direction toward south and west
Elevation class 1000-1500 m; slope class 30-100% with direction toward south and west
Elevation class 1500-2000 m; slope class less than 15% with direction toward south and west
Elevation class 1500-2000 m; slope class 30-15% with direction toward north, east, south and west
Elevation class 1000-1500 m; slope class 30-100% with direction toward north and east
Elevation class less than 1000 m; slope class 30-100% with direction toward north and east
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Study procedures
two different parts of assessment:
index
assessment of the environment under the impact along the pipeline.
Identification of assessment index:
project specifications:
• equipments type, designing used in pipeline
• physical and chemical specifications of the transferred fluid
• type of activity, technology
• pipe structure
Analyze of impact receptive environment:
• hydrologic, climatic, geologic, pedologic, biologic and socioeconomic
• sensitive species and habitat
• land usage and construction activities
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Weighting of sub index and informative layers:
• considered 50% for both Index
• Index sum and leak impact factor
• compared pairwise for determining their degrees of
significance
• AHP and software of expert choice 11
• expert suggestions and pairwise comparisons of indicators
through the analytical hierarchy process(AHP)
The final risk value:
dividing Index sum on leak impact factor
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Table (6) : final weights for criteria and sub index of
risk in pipeline risk assessment
Assessment index
Significant
percent
Sub indexFinal weightcriteriaweight
Index Sum50%
Third-party
damage Index
0/578
Population center(to 2 Km)0/146
Connection line(to 1 Km)0/051
Exist gas pipeline0/097
Convection line0/035
Land use0/426
Ground installation0/245
Incorrect
operation index
0/134×1
Design0/228
Type of soil(overlay of quake, flounder
and land settle)
1
corrosion0/06Soil corrosion1
Result of this overlay is Sum Index map
Leak impact factor50%
Product hazard0/333×1
Dispersion
sensitivity
0/097Population density (to 2 Km)1
Ecological
sensitivity
0/570rivers1
Result of this overlay is Leak impact factor map
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Risk assessment by integration of Index sum and
leak impact factor:
• Risk assessments final score
• overlaying of these maps
• using GIS system
• according to set guidelines
Index sum:
first index in calculation of environmental risk assessment
five different sub index :
third party risk, corrosion, designing and operating efficiency
• lower score for higher risk probabilities
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leak impact factor
• second index in calculation of environmental risk assessment
• consequences of a failing event
• higher score for higher impacts
four different sub index
• transferred fluid
• amounts of environmental leakage
• degrees of dispersion
• impact receptive environment (ecological sensitivity)
final map of risk in the study area :
dividing the two maps of Index sum and leak impact factor
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Considering the purpose of this
study, the area was divided to
three different elevation
classes of <1000 m, 1000-
1500 m and 1500-2000 m.
The class with the elevation of
1000-1500 m has constituted
the biggest area (about 65%).
Elevation class (m) Area (ha) %
Less than 1000 25550/22 23/19
1000-1500 71814/09 65/18
1500-2000 12815/17 11/63
total 110179/48 100
Table 1: Elevation class and the area
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Following the objective
of the study, the area
was separated to
three different slope
classes with biggest
area (61.92 %) the
slope class of <15%.
The study area is also
divided to 5 main
direction classes with
30.05% of the
directions facing
toward south.
slope class (%) Area (ha) %
0-15 68218/93 61/92
15-30 25447/80 23/10
30-100 16512/75 14/98
total 110179/48 100
Table 2: slope class and the area Table 3: direction class and the area
direction class (%) Area (ha) %
p 74/89 0/07
North 29816/35 27/06
East 24902/45 22/60
South 33110/53 30/05
west 22275/26 20/22
total 110179/48 100
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land units:
• determine the type of soil and its vegetations
• each land unit could be representative of a macro ecosystem
• merge of different maps of slope, elevation and direction classes
• creates a map with three different units of:
• suitable, moderate and unsuitable
Table 4: merged code of slope and elevation classes
Number of class 1 2 3
Number of class
Elevation
Slope
Less than 1000m 1000 -1500m More than 1500 m
1 Less than 15% 11 21 31
2 15-30% 12 22 32
3 More than 30% 13 23 33
Degree of suitability in merge of elevation and slope classes for pipelining path
could be measured as below:
Code of units with high suitability or suitable: 11, 12, 21
Code of units with moderate suitability: 13, 22, 31
Code of units with low suitability or unsuitable: 23, 32, 33
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Number of
class
1 2 3 4 5
Direction
Merge
code slope and
elevation
p North East South West
11 111 112 113 114 115
12 121 122 123 124 125
13 131 132 133 134 135
21 211 212 213 214 215
22 221 222 223 224 225
23 - 232 233 234 235
31 - 312 313 314 315
32 - 322 323 324 325
33 - 332 333 334 335
Table 5: merged code of land unite classes
Code of units with high suitability or suitable
Code of units with moderate suitability:
Code of units with low suitability or unsuitable:
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Scoring using indexing method
Analysis result of risk
assessment shows:
Risk assessment
scores for sub index
of third party damage
corrosion, design and
Incorrect operation
index were 48 of 100,
87 of 100, 68 of 100
and 83 of 100
respectively with
third party damage
as the highest risk in
compare to other
possible threats
Table (7): summary of semi-quantitative scoring using indexing method
indexSub indexcriteria
weightin
g
scale
1
sum index
Third-party
damage Index
Minimum Depth of
cover
20%
0-20
14
2Activity level
20%
0-20
15
3Above ground facilities
10%
0-10
3
4Line locating
15%
0-15
5
5
Public education
programs
15%
0-15
6
6Right-of-way condition
5%
0-5
3
7Patrol frequency
15%
0-15
2
8
corrosion
Atmospheric corrosion
10%
0-10
10
9Internal corrosion
20%
0-20
20
10Subsurface corrosion
70%
0-70
57
11
design
Safety factor0-3520
12fatigue0-159
13Surge potential0-1010
14Integrity verification0-2520
15Land movements0-159
16
Incorrect
operation index
design0-3029
17construction0-2016
18operation0-3529
19maintenance0-159
20
impact
Leak impact
factor
Product Hazard(PH)0-227
21Leak/spill volume(LV)−3
22Dispersion−3
23Receptors(R)−3/4
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Environmental risk in direct impact area
Environmental risk zoning for direct impact area were calculated after
dividing Index sum on leak impact factor through 4 different risk intensity
score. According to table (8), score 4 as a moderate risk was considered
highest in terms of the surface area among the other risks intensities with
low risk, very low risk and high risk in descending order.
Table(8): Weight of different score area of Environmental risk zoning
in
direct impact area
Risk score
Area of
risk
score(ha)
Score of weight
risk(or weight of
area)
Ratio score of
weight risk
3 12/47 37/41 0/0021
4 3249/60 12998/4 0/73
8 553/69 4429/52 0/25
9 15/37 334/35 0/019
total 3831/13 17779/68 1
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Risk zoning in different land units
Distributions of different risk scores in land units show highest surface
area belong to score 4 in unsuitable land units 3,
in result:
unsuitable Environmental area face to higher risk.
Table (9): Risk score distributions in different land units
Land unite
Risk
score
Area of land unit risk
score (ha)
Score of weight
risk(with weight
area))
Ratio score of
weight risk
% ranking
1 3 11/82 35/46 0/002
21
7
1 4 927/91 3711/64 0/21 3
1 8 - - - -
1 9 - - - -
2 3 0/28 0/84 0/00
33
8
2 4 967/46 3869/84 0/22 2
2 8 207/89 1663/12 0/09 5
2 9 15/37 138/33 0/01 6
3 3 - - -
46
-
3 4 1354/23 5416/92 0/31 1
3 8 345/80 2766/40 0/15 4
3 9 - - - -
total 3830/76 17602/55 1 100 -
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Fig(7): Merging of risk with different land units
Chart: relation between pipeline risk scores and their surface area in different land units
0
500
1000
1500
2000
2500
3000
3500
3 4 8 9
Area(ha)
Risk score
3 4 8 9
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environmental risk assessments for gas pipelines
• not be calculated only base on possible human casualty
• be able to consider wider dimensions of human, environmental and
economical impacts of pipeline at the same time
to have more efficient environmental risk assessment for gas
transmission pipelines and also other activities, land units should be considered
as the base units of study.
CONCLUSION
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Thank You For Your Attention !
Maryam Khaleghian
PhD student of Environment, Dept of environment and Energy, Islamic Azad
university
Iran
Email: mkhaleghian2@gmail.com
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Zoning of Gas Pipeline Environmental Risk Assessment in Various Land Unit, Maryam KHALEGHIAN

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Zoning of Gas Pipeline Environmental Risk Assessment in Various Land Unit, Maryam KHALEGHIAN