USE OF GIS FOR DESIGNING A PIPELINE (GAS) ROUTE FROM THE DALLAS NAVAL AIRSTATION TO THE DALLAS LOVEFIELD

AIRPORT

By: Nilanjana Bhattacharjee

For: GEOG 5520-Intermediate GIS Dr. Minhe Ji May 5, 2004

INTRODUCTION: Texas ranks number one in the United States in production of oil and natural gas. Pipeline is a major transporter of oil and natural gas. Clean burning natural gas has become the fuel of choice for homeowners, businesses and electric power generators searching for ways to reduce the air pollution. Natural gas is the cleanest burning fossil fuel. Pipelines are the most efficient, cost effective and environmentally friendly means of fluid transport. Transmission or trunk pipelines are examples of engineering marvel requiring high project cost and long gestation periods and operating life. Careful planning of their route can save on cost, time and operating expenses, ensure longer operational life and help prevent environmental fallouts.

Throughout the world, a large network of pipes transports oil, gas, water and different products. Pipeline transport is most prevalent in USA where nearly two-thirds of the ton-miles of oil get transported annually through a network of more than two million kilometers of pipelines, in some of the toughest terrains. Pipelines are by far the most economical, practical and safe option of fluid transport. They save enormously due to their tenfold efficiency over trucking / railroad operations and accrue important environmental and safety benefits by reducing the highway congestion, pollution and spill. This inexpensive, reliable and high capacity transport is critical to national economy and security.

The pipelines are used for transmission, distribution and gathering. The most sophisticated and large pipelines fall in the transmission category. These are often large diameter (>100 cm dia.) pipelines incorporating automated monitoring and control of flow, pressure and fluctuations. These pipelines are highly capital-intensive installations with long lead and long life. Typical installation costs range from $120,000 / km for water pipeline to $400,000/km for gas pipelines with oil pipelines at intermediate range of $200,000. Material and laying components account for 70-90 per cent of cost. The construction of pipeline is facilitated by proper analysis of route location for access to right of way, terrain for obstructions and weather for movement of equipment.

The study area is confined to Dallas County, in north –central Texas, is bordered by Kaufman and Rockwall counties to the east, Tarrant County to the west, Denton and Collin counties to the north, and Ellis County to the south. Dallas is the county seat and largest city. The county's center point is at 32°30' north latitude and 94°30' west longitude. Dallas County comprises 902 square miles of the primarily flat, heavy Blackland Prairie. Elevations in the county range from 382 to 584 feet above sea level. The Elm Fork and West Fork of the Trinity River meet near downtown Dallas. The Trinity River and its tributaries, including White Rock, Mountain, Fivemile, Tenmile, Muddy, Duck, Turtle, and Mesquite creeks, drain the county. These streams feed reservoirs for municipal water and recreational use, including Lake Ray

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Hubbard, Lake North, Joe Pool, Mountain Creek and White Rock Lakes. The terrain is generally undulating. The eastern two-thirds of the county and the land along the western border is surfaced by slightly acidic clayey soils with loamy topsoil. The rest of the county's soil is alkaline and loamy. The county has tall grasses with pecan and oak trees along streams and mesquite on the prairies. Though the rich soil is the main mineral resource of Dallas County, gravel and sand have been mined from the Trinity floodplain, cement has been made from the local soft limestone, and bricks have been manufactured from the county's clay. Temperatures range from an average high of 95° F in July to an average low of 36° in January. The average rainfall is thirty-six inches a year. The growing season lasts 235 days. Objectives:

This hypothetical project is an important application of GIS—corridor studies, which may be used to examine the impact of an existing linear facility (such as a road), or to evaluate alternative routes for a proposed new facility. The goal of this project is to select a possible route for a pipeline from the Dallas Naval Air Station to the Dallas Love Field Airport. Criteria for selecting the route is two folded:

a) Minimizing number of main roads, freeways, railroads and streams crossing b) Finding a cost-weighted path between the two airports.

Along with this two major objectives there is also a minor objective c) To avoid the proximity to multiple schools (for an emergency leak).

LITERATURE REVIEW:

The study of literature helps to clarify the thinking to write a statement describing and evaluating the available literature pertaining to the study. (Haring and Lounsbury). Pipeline operation entails a comprehensive strategy for routine operations and maintenance, damage prevention, safety, security, environmental protection and emergency response. Many of these factors fall within the regulatory framework and require compliance. Routes passing through unusually sensitive areas like water supply reservoirs, populated areas and ecologically sensitive areas need extra precautions against accidental spillage. Mapping of pipelines for administering a sound operations program is now considered essential (R PDubey).

Scientific planning of pipeline route can reduce cost and time of project execution and hence the operating expenses. Pipeline alignment is basically an optimization between costs of the material and the construction. Natural and man-made terrain obstructions cause spatial variation in construction cost due to changing thematic features like types of soils, intervals of slope, etc. Manual pipeline route planning uses available maps, surveys and experience and is seriously constrained due to lack of updated data and quantitative approach. This is accentuated for complex terrains and long routes. Remote sensing (RS) and GIS method on the contrary uses updated maps from latest RS data, integrates thematic cost layers in GIS environment and computes all possible routes with associated costs. Apart from saving 5-15 % route length, the method has potential benefits like cadastral overlays on route for gadget notification, precise location data on installations and organization of O&M (Operations and Maintenance data).

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METHODOLOGY:

Methodologically the flow of this research remains stringently scientific and objective. The research design followed a simple yet the most effective route possible (see FIG. 2 Flow chart). The main source of data for this research is the ‘North Central Texas Council of Governments’ (NCTCOG). The base study area for the project is within the confines of Dallas County, Texas. Fundamentally, the initial challenge was amassing the proper data and placing it into usable coordinate format. All the data layers are in North American Datum 1983 which are the following:

i) All the airports of Dallas county ii) The streams iii) The freeways iv) The railroads v) The main roads vi) The water bodies and vii) The landmarks.

FIG.2 Research design Flowchart

The next step was to create an empty shape file in Arc catalog to put the new Pipeline (which would be created) into that shape file and then to import that empty shape file to the study area map. STUDY AREA:

Data Source: NCTCOG

Extraction of necessary Data layers

Analysis of Data Layers

Results and conclusion

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FIG.1 Study Area

After that the locations of all the schools in Dallas County were extracted from the

landmarks so that density of schools can be extracted. Then from all the air stations in Dallas county region only two air stations, which serves as the source and destination for this research project, has been put into the data layers. (The two airports have been selected arbitrarily; any object could be chosen as source and destination but between these two airports density of streams, Main roads, Railroads and Freeways all are comparatively higher which is a challenge for analysis).

To design a pipeline route from the Dallas Naval Air Station to the Dallas Love Field Air Station two different types of methods had been adopted:

a) First the density of streams, main roads, freeways, railroads and the density of schools were calculated in spatial analysis. As there were no water bodies in between the two air stations so the density of water bodies has not been calculated. Then according to the density of all the four category one combined density was calculated where equal weight was given to the density of Railroads, Main roads, Freeways and streams (22% each) and a lesser percentage

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(12%) of weight to density of schools because the aim is to get an least cost route between the two Air stations and the presence of these above mentioned features (except schools) can increase the cost. It is better to avoid any sharp turns to decrease the construction cost.

b) From the combined density raster data one least cost possible route for the pipeline was created and finally a possible pipeline route was constructed.

The densities were calculated in spatial analysis and the five different raster layers of density of Streams, main roads, freeways, railroads and the schools were the consequent intermediate results. To calculate the density of all the different data layers kernel calculation was chosen because in kernel calculation the points or lines lying near the center of a raster cell search area are weighted more heavily than those lying near the edge. So the result is a smoother distribution of values.

FIG.2: Density of freeways

FIG.3: Density of Rivers

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FIG.4: Density of Main Roads

FIG.5: Density of Railroads

FIG.6: Density of Schools

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It is difficult to work with densities of all different features and to get combined effect of all the five factors one combined density had been calculated in raster calculator. The combined density effect was done with assigning a percentage value according to their importance for the construction. An equal importance of 22% was given to the density of streams, density of Railroads, density of Freeways and the density of Main Roads whereas a little lesser percentage (12%) of importance was given to the density of schools. (See FIG. 7)

FIG.7 Combined density map showing desired areas for the Pipeline

Taking the combined density as an input raster then a cost weighted path was calculated which would be helpful to demonstrate the suitable path for the construction of the pipeline. (See FIG.8)

A possible route for the pipeline was then constructed following the cost weighted path. Cost weighted distance mapping finds the least accumulative cost from each cell to the nearest, cheapest source. Here cost weighted distance has been used to minimize construction costs for routing the pipeline. The main criteria for the selection of the possible route were to avoid any sharp bending and minimizing the total length of the pipeline. The total length was also calculated which was about 11 miles (Table 1) from source to destination.

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FIG.8 showing a cost weighted path for the pipeline.

Table 1. Showing the length of the pipeline.

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To find a cost weighted path it is not necessary to take the raster layer of density of schools situated in that area, but one of the criteria to a suitable route for the pipeline was to avoid schools so that in any emergency case (leak) those schools can be notified or less number of schools can be affected in any case of accidents.

The proposed pipeline intersected only two rivers—West fork Trinity River and Elm Fork Trinity River. The two Freeways intersected by the pipeline were I-35 and I-30. Carpenter Road was the only main road intersected by the Pipeline and the three railroads, which had been passed by the pipeline, were Chicago Rock Island and Pacific, Texas and pacific railway and the Missouri-Kansas-Texas railroad. (See FIG.9)

FIG.9 Possible route for the pipeline. CONCLUSION:

Competitive pressure and regulatory constraints are placing increasing demands on pipeline operators to operate in an efficient and responsible manner. Responding to these demands requires accessibility to information regarding geographically distributed assets and operations. GIS provides the pipeline operator with improved capability to manage pipeline integrity, improved efficiencies in pipeline operations, and improved response to business development opportunities. This research might help and guide the pipeline operators and planners for a selection of a suitable route for a gas pipeline construction.

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REFERENCES: 1. GIS application - www.gisdevelopment.net 2. The handbook on Texas- www.tsha.utexas.edu/handbook/online

3. Barbara Pando--Bolivian gasPipelineConstruction. www.american.edu/projects 4. Goldfields Gas Pipeline Coverage Revocation: KPMG’s comments on report by

Frontier Economics-- www.ncc.gov.au 5. Introduction to Scientific Geographic Research –Haring and Lounsbury (1971).

6. Dr.Ronald Briggs -- Professor at University of Texas at Dallas. 7. ArcView Exercise Book—Hohl and mayo. (Chapter 9). 8. Using ArcGis Spatial Analyst. 9. Remote Sensing and Image processing—R.P. Dubey (Value added services cell).

FLOW CHART

Dallas County

Streams Rail Roads

Main roads

Freeways

Water Bodies

Landmarks

Airports

Schools

Source and Destination

Density of Streams

Density of Rail Roads

Density ofMain roads

Density ofFreeways

Density of Schools

Combined Density (Using Raster Calculator)

Cost Weighted Path