Sunday, 23 July 2017

PROPOSAL FOR ROUTE, LOCATION AND RIGHT-OF-WAY SURVEY

SURCON QUESTION: YOUR FIRM HAS BEEN CONTRACTED ABOUT CARRYING OUT A ROUTE, LOCATION AND RIGHT-OF-WAY SURVEY OF THE EXTENSION OF THE NIGERIA RAILWAY LINE FROM AJAOKUTA IN KOGI STATE TO DELTA STEEL COMPANY IN ALADJA IN DELTA STATE. PREPARE A DETAILED PROPOSAL FOR THE CLIENT, WHICH SHOULD INCLUDE FINANCIAL ASPECTS.

Introduction
The survey shall provide geospatial data needed for design, setting-out and construction of the railway line. The project shall be sub-divided into the following procedures.
1.      Reconnaissance survey
2.      Connection survey
3.      Establishment of control points
4.      Marking of centerline and cross-sections
5.      Detail survey and corridor mapping
6.      Right-of-way survey
7.      Processing and plotting

NOTE: Here, we shall only describe the works that shall be done. The financial aspect follows the direct cost for scale of fees described @ PROPOSAL FOR PERIMETER AND TOPOGRAPHICAL SURVEYS. The reader should attempt to do the calculation.

Reconnaissance Survey
Reconnaissance survey shall consist of two parts. Firstly, planning the project shall be carried out during which existing topographic maps covering the project length would be studied. Probable centerline of the proposed railway line would be identified. Government control points would also be identified. Other features that shall be identified in along the project corridor include towns, villages, rivers, hills, bridges, farmlands and swamps.

Secondly, field reconnaissance shall be carried out during which the survey control points shall be located on the ground. Also, suitable and inter-visible locations for more control points shall be identified and marked on the ground. Finally, the proposed centerline shall be identified and adjusted and obstructions along the centerline shall be noted.

Connection Survey
Global Positioning System (GPS) equipment shall be deployed to carry out connection survey in order to connect the project to national framework of government control points. This shall serve as geodetic backbone for the entire project.

Further control points shall be extended to the project area. The control points shall be cast in accordance with the specifications given by Surveyors Council of Nigeria. The cast beacons shall be allowed to settle for three days before survey can be carried out on them.

Marking of Centerline and Cross-Sections
The final adjusted centerline shall be pegged at 25m interval beginning from chainage 0+000 at the beginning of the project. At each chainage along the centerline, cross-sections shall be taken at 10m intervals up to 50m on both the left-hand-side and right-hand-side of the centerline.

Corridor Mapping and Detail Survey
The railway corridor shall be mapped 50m on either side of the centerline. Every feature along the corridor shall be identified and surveyed, such as road crossings, built-up areas, rivers, bridges, farmlands, pipelines, plantations and swampy areas.

During the corridor mapping, the right-of-way survey shall be carried out, during which features that fall within the right-of-way shall be identified and surveyed.

Data processing and presentation
During data processing, the following map products shall be generated:
·         Digital terrain model (DTM)
·         Contour map
·         Longitudinal profile
·         Cross-sections
·         Plan showing the centerline and all features along the corridor.

Accuracy
The project shall be of third-order accuracy; that is, not less than 1:3000.

Conclusion
The survey shall be concluded within a period of one month.


DISCLAIMER: This material is only an attempt to answer an examination question, though written from a background of solid knowledge and practical experience in Surveying and Geoinformatics. It has not gone through peer review. Therefore, all views and opinions expressed therein remain the responsibility of the author and do not necessarily represent that of any institution.  Feedback on corrections and constructive criticisms are welcome. Thank you.

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