1. Pipeline Design - Protecting the Environment:
Application of GIS to Pipeline Route Selection
Keith Winning
Uganda Investment Forum - Driving Growth in Africa
Kampala, Uganda 11th - 12th April 2013

3. Uganda Investment Forum – Driving Growth in Africa
th
th
Kampala, Uganda 11 – 12 April 2013
Pipeline Design – Protecting the Environment:
Application of GIS in Pipeline Route Selection
Presentation by: Keith Winning CB&I
Abstract The effects of soil erosion worldwide are a
major concern; it impacts on the environment, food
security and public health. It is estimated that 75
billion metric tons of soil worldwide are lost per
annum; with Africa, Asia and South America typically
experiencing average losses of 30 to 40 tons ha-1 year-1,
with the accepted sustainable rate of soil loss being less
than 10 tons ha-1 year-1.
Soil erosion is the process of soil loss due to
detachment, transportation and deposition of soil by
water or wind and is dependent on a number of factors,
including: rainfall energy, soil strength and cover,
slope length and angle, crop and land management.
The effect of soil erosion is two-fold; on-site impacts
include the loss of soil functions, structure and fertility,
while the off-site impacts include the increased
turbidity and eutrophication in water courses.
Figure 1 – Erosion types (Sheet, rills and gullies)
The severity of the erosion is rated by a simple scoring
system based on the identification of the visible erosion
features, with the accepted sustainable rate of soil loss
is less than 10 tons ha-1 year-1 (erosion risk 3) [1].
By using remote sensed data and spatial analysis within
the application of a Geographical Information System
(GIS), it is possible to predict the soil loss (erosion
risk) at the initial route selection phase of the project.
This enables the engineer to select a route which
minimises the environmental impact due to soil erosion
and provide better input to the capital expenditure
(CAPEX) costs and the operational (OPEX) costs for
the pipeline which are used to determine the optimum
configuration and route selection of the pipeline.
Erosion
Risk
Keywords Soil Erosion  Pipeline Routing  GIS 
USLE  Environment Impact
K. Winning ()
Principal Pipeline & Geomatics Engineer
CB&I, 40, Eastbourne Terrace, London. W2 6LG.
Tel:
+44 (0)20 7053 3778
e-mail: kwinning@cbi.com
1.
Introduction
Soil erosion is the process of soil loss due to
detachment, transportation and deposition of soil by
water or wind and is dependent on a number of factors,
including: rainfall energy, soil strength and cover,
slope length and angle, crop and land management.[1]
Erosion is broadly defined as being:
• Sheet or inter-rill: where the soil is removed in
uniformly thin layers and the flow is
unconfined (overland flow).
• Rill: Initiated at a critical distance down slope
when the overland flow becomes channelled.
This is temporary and can be ploughed out.
• Gully: Confined, channelled and permanent.
1
2
Erosion
Rate
(tonnes/ha)
<2
2–5
3
5 – 10
4
10 – 50
5
50 – 100
6
100 – 500
7
> 500
Visual Assessment
No wash marks or scours.
Shallow rills every 50 –
100m.
Discontinuous rills every
20 – 50m.
Continuous network of rills
every 5 – 10m or gullies
every 50 – 100m.
Continuous network of rills
every 2 – 5m or gullies
every 20m.
Continuous network of
channels with gullies every
5 - 10m.
Extensive network of large
gullies every 20m
Table 1 – Erosion Risk Classification [1]
The effective use of erosion control in agriculture has
long been established, with early work carried out in
America by Hugh Bennett in the 1920s. From this
work, mathematical models to predict soil loss have
been developed, the Universal Soil Loss Equation
(USLE) Equation (1), issued in 1965 [2] and the
Revised Universal Soil Loss Equation (RUSLE) in
1978 [3]; further models have since been developed,
including the Morgan-Morgan-Finney (MMF) [4].
Increasingly, it is being recognised that soil erosion due
to construction has significant environmental impacts
[1].
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4. Uganda Investment Forum – Driving Growth in Africa
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Kampala, Uganda 11 – 12 April 2013
A=R×K×L×S×C×P
Where:
A = Soil loss in tons ha-1 year-1
R = Rainfall factor
K = Soil erodibility factor
L = Slope length in metres
S = Slope factor
C = Crop factor
P = Support practice factor
to eutrophication caused by the run-off of fertiliser rich
soil into the Volga River.
Equation 1 – Universal Soil Loss Equation
2.
The Effects of Soil Erosion
Figure 3 – Caspian Sea showing eutrophication
(http://visibleearth.nasa.gov/view.php?id=66761)
3.
Figure 2 – Gully erosion in highly erodible soils
The effects of soil erosion worldwide are a major
concern; it impacts on the environment, food security
and public health. It is estimated that 75 billion metric
tons of soil worldwide are lost per annum [5]; with
Africa, Asia and South America typically experiencing
average losses of 30 to 40 tons ha-1 year-1[5].
Soil Erosion and Pipelines
In addition to the impact of soil erosion already
discussed, erosion control for buried pipelines is
important in order to reduce the environmental impact
and reduce the risk of exposing the buried pipe [1].
Exposure of buried pipelines can lead to free spanning
where a length of the pipeline is unsupported, which
can result in mechanical failure; in such cases the effect
on the environment can be significant.
On-site impacts include the loss of soil function from
the breakdown of the soil structure and the reduction in
organic matter. The outcome of this is reduced yields,
loss of arable land, reduced food security and risk to
existing infrastructure such as roads, railways and
pipelines.
Off-site effects, due to the transportation of sediment
include the increased turbidity in water courses leading
to public health issues and a risk to infrastructure
(hydroelectric generation and irrigation) [6]. With
increased turbidity comes eutrophication or
hypertrophication, which is the response of aquatic
systems to raised levels of nitrates or phosphates. This
leads to hypoxia, a reduction of oxygen in the water
and rapid growth in algae [7].
Figure 3, taken from the Moderate Resolution Imaging
Spectroradiometer (MODIS) on the Terra satellite on
June 11, 2003 shows the growth of the algae in the
northern part of the Caspian Sea (shown in green), due
4
Figure 4 – Pipeline spanning due to soil erosion
Once a pipeline has been installed, the right-of-way is
reinstated and if possible the original ground cover reestablished. Soil erosion due to rainfall energy can
cause the bio-restoration to fail due to soil detachment
and washout of young seeds due to runoff.

5. Uganda Investment Forum – Driving Growth in Africa
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Kampala, Uganda 11 – 12 April 2013
Erosion at this level will necessitate post installation
monitoring and remedial works, adding to the
operational (OPEX) cost of the pipeline.
Any
construction work involving the temporary removal,
storage and return of the topsoil and compaction of the
subsoil by machinery increases the potential for soil
erosion due to reduced porosity, as the infiltration rate
on the compacted soil is reduced, resulting in greater
runoff and poorer rates of bio-restoration and therefore
greater erosion [8].
4.
Application of GIS to Route Selection
Geographical Information Systems (GIS) integrate
hardware, software and data for capturing, managing,
analysing and displaying geospatial data. GIS can aid
in the route selection process in a number of ways; one
of these is by predicting the soil loss (erosion risk).
Using public domain data enables this to be carried out
during the initial route selection phase of the project.
Using Landsat imagery with bands 5, 4 and 3 (infrared,
near infrared and red), healthy vegetation is displayed
in bright green and bare soils in mauve. This is then
classified into 6 classes by the RGB colour value:
water/ice, vegetation, cloud cover, rock, soil and
soil/rock; from this an assessment of the soil erodibility
factor (K) can be predicted. The Shuttle Radar
Topography Mission (SRTM) provides a highresolution (90m) digital elevation model of 80% of the
world’s land mass. This is used to determine the slope
factor (SL). In order to determine the rainfall factor
(R), data from the World Meteorological Organization
(WMO), the annual rainfall data was plotted and a
choropleth map produced. The crop factor (C) and the
practice factor (P) are 1 as the pipeline right of way,
initially has no vegetation immediately after
reinstatement.
By using GIS and remote sensed data it is possible to
predict the soil loss (erosion risk) along a proposed
pipeline route, early in the route selection phase. From
this the post construction requirements to ensure that
soil loss is less than 10 tons ha-1 year-1 (erosion risk 3)
are determined, which include seeding, matting, berms
and outlets [9].
This aids the engineer in minimising the erosion risk of
the pipeline route at the initial route selection phase of
the project. In addition it forms the basis for
identifying those areas that are more susceptible
(erosion risk 4 to 7), to soil erosion for field
verification.
5.
Conclusions
As our demand for oil and gas increases, the diameter
and length of the pipelines required to transport these
commodities increases, with this comes the potential
for greater environmental impact.
By using remote sensed data and spatial analysis within
the application of a Geographical Information System
(GIS), it is possible to predict the soil loss (erosion
risk) at the initial route selection phase of the project.
This enables the engineer to select a route which
minimises the environmental impact due to soil erosion
and provide better input to the capital expenditure
(CAPEX) costs and the operational (OPEX) costs for
the pipeline which are used to determine the optimum
configuration and route selection of the pipeline. In
addition, it identifies those areas that require field
verification.
Acknowledgements
The author would like to thank Professor Hann of
Cranfield University for reviewing this paper.
References
[1] Morgan RPC. Soil erosion and conservation. Third
Edition: Wiley-Blackwell; 2009.
[2] Wischmeier WH, Smith DD. Predicting RainfallErosion Losses from Cropland East of the Rocky
Mountains. In: Agricultural Research Service USDoA,
editor. Washington D.C.1965.
[3] Wischmeier WH, Smith DD. Predicting Rainfall
Erosion Losses. In: Agricultural Research Service
USDoA, editor. Washington D.C.1978.
[4] Morgan RPC, Morgan DDV, Finney HJ. A
predictive model for the assessment of soil erosion risk.
Journal of Agricultural Engineering Research.
1984;30:245–53.
[5] Pimentel D, Harvey C, Resosudarmo P, Sinclair K,
Kurz D, McNair M, et al. Environmental and economic
costs of soil erosion and conservation benefits.
SCIENCE-NEW YORK THEN WASHINGTON-.
1995:1117-.
[6] Holmes TP. The offsite impact of soil erosion on
the water treatment industry. Land Economics.
1988:356-66.
[7] Vollenweider RA. Scientific fundamentals of the
eutrophication of lakes and flowing waters, with
particular reference to nitrogen and phosphorus as
factors in eutrophication. OECD REPORT,
SEPTEMBER 1970 159 P. 1970.
[8] Mohitpour M, Golshan H, Murray MA, Mohitpour
M. Pipeline design & construction: a practical
approach. Third Edition Edition: ASME press New
York; 2000.
[9] Morgan RPC, Mirtskhoulava TE, Nadirashvili V,
Hann MJ, Gasca AH. Spacing of Berms for Erosion
Control along Pipeline Rights-of-way. Biosystems
Engineering. 2003;85:249-59.
©CB&I 2013
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Appendix – Presentation Slides
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Kampala, Uganda 11 – 12 April 2013
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12. Keith Winning
Principal Pipeline & Geomatics Engineer
Project Engineering and Construction
Office: +44 (0)20 7053 3778
E-Mail: kwinning@CBI.com