When the question of construction a new road arises due to public demand or some strategic reason, a primary investigation is carried out to examine whether this road is necessary. The following points are to be kept in mind at the time of such investigation:
- Total population benefited by the project.
- Number of villages, towns industrial places, etc. to be connected.
- Agricultural products, industrial products, minerals, etc. are likely to be conveyed through the proposed road and thus help the development of trade in the country.
- Prospect of tourism, if any.
- Strategic importance for the defense of the country.
- Any other information related to the project should be noted
Marking the Tentative Alignment
After primary investigation regarding the justification of constructing a new road, the tentative alignment or alignments are marked on the general map and contour map of the area through which it is expected to pass. While marking the tentative alignment, the following points should be considered
- The proposed road should connect a sufficient number of villages, towns, industrial places, places of religious importance, etc.
- The alignment should be taken in such a way that unnecessary cutting and banking can be avoided.
- If the alignment crosses a river, it should do so perpendicularly through the shortest width of the river.
- The alignment should not pass through religious places like temples, churches, mosques, etc. or burial grounds, burning ghats and so on.
- The alignment should not be taken completely through valuable agricultural land.
- The alignment should not pass through the heart of villages, towns, etc, where the compensation payable is likely to be more.
- Any other obstacles or problems should be considered during reconnaissance survey
Reconnaissance Survey (Reconnoiter)
Before starting the actual survey work, a reconnaissance survey is conducted along the tentative alignments to select the most suitable alignment. The following points should be noted during reconnaissance:
- The magnetic bearings of the lines of alignment are measured by prismatic compass and noted in a field book.
- The distances along the alignment are measured approximately by pacing (one pace or walking step is taken as 80 cm or 2.5 ft).
- The objects and nature of the ground on both sides of alignment, up to 50 m, are noted in the field book.
- Obstacles like religious place or valuable structures, if any, should be suitably crossed over.
- If the tentative alignment crosses a river obliquely or passes through a wide cross-section of it, then the alignment is diverted suitably to cross the river perpendicularly and through is shortest width.
- All other important points like railway crossings, canal crossings, etc. should be noted.
- The highest flood level ever attained and the discharge records for the last 10 year should be collected from the appropriate authorities to design the culverts and bridges.
- Preliminary records should be prepared of properties eligible for Compensation.
Preliminary Location Survey
After reconnaissance survey, a suitable alignment or alignments are selected for preliminary location survey for detailed investigation to obtain the most economical alignment.
Final Location survey
The most economical alignment is selected by analyzing the merits, demerits, cost of construction, etc. for the proposed alignments after preliminary location survey. Before the approval of the project is obtained from the higher authorities, the final location survey is completed in all respects. The following steps are taken for final location survey.
After completion of all investigation work, survey work design of different structures, and total estimate for the project, a report should be prepared and submitted to the higher authorities for approval. The report prepared should include information related to the following:
- Introduction to the project
- Necessity and background of the project.
- Justification for selection of the final alignment and the procedure adopted for land acquisition
- Detailed estimate covering all items-earth work, road surface, culverts, bridges, compensation, etc.
- Detailed specification for the constructional works
- Overall benefit of the project
- Conclusion and recommendation
- Maps to be submitted along with project report: (a) General map of the country through which the proposed road will pass (b) Route survey map (to suitable scale) (c) Longitudinal section (to suitable scale) (d) Cross-section (to suitable scale) (e) Detailed drawing of culverts, bridges, flyovers, etc