Pipeline river crossing surveys

By: Aquacoustic  09-12-2011
Keywords: inspections, Pipeline, Sonar Data

Pipeline crossings and other river bottom features can present hazards in waterway systems. Over the course of time, or because of floods, poor installation, tide action, river traffic, or unusual conditions, these features can change location with respect to the bottom – with potentially disastrous results. AquaCoustic has found situations where, for example, high pressure gas pipelines have become suspended above the river bottom presenting a major hazard to shipping and the surrounding area.

The US Government mandates that pipelines crossing inland navigable waterways in excess of 100 ft in width maintain a cover of 48 inches, and are to be inspected once every five years. Visual inspections are not adequate for this purpose.

Real-time assessment of pipeline river crossing conditions with a rotating head sonar:

A rotating head sonar survey is a fast and economical way of alleviating potential hazards. The sonar head can be deployed from a small vessel or a dock and provides extreme accuracy. The recorded data is viewed in real-time in order to assess data quality and to identify unusual bottom or sub-bottom features that may require further investigation. This provides us with the ability to perform rapid, investigate inspections after a suspected incident. AquaCoustic is able to draw on a wide range of additional technologies (see the technology section of this web site) depending on survey conditions, and the acquired sonar data can be geo-referenced to marine charts, provided as 3D drawings, or in a variety of other forms.

River crossing sub-bottom profiling:

Sub-bottom profiling systems can be useful for calculating pipeline cover, areas of concern, or in preparation for laying new pipes or cables. The penetration depth depends on the hardness of the overlying layers and the presence of gas deposits. In some cases, the type of bottom cover can be determined.

Rotating head sonar offers specific advantages for river crossing surveys:

  • Ideal for areas such as shorelines, shallow areas and dredged channels.
  • Obtain detailed XYZ data from under log booms, overhangs or vessels.
  • Provides earthquake values for slopes.
  • Economical enough for regular inspections.
  • Measure scouring and undermining accurately.
  • Pitch and roll system is accurate to 0.1°
  • The system is small and can be mobilized and set up easily, keeping costs down.

Locate bottom and sub-bottom hazards or conditions such as:

  • Pipes and pipelines
  • Catenaries
  • Depth of cover
  • Scouring around submerged structures
  • Cables
  • Debris
  • Boulders
  • Buried scarps
  • Collapsed features
  • Bedrock pinnacles
  • Potentially sensitive layers
  • Unstable slopes

Keywords: inspections, Pipeline, Sonar Data

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