The experience gained during the operation and maintenance stages of the Camisea pipeline transportation system (STD) in Peru, crossing from the Tropical jungle in the Cusco region to the coast, in Lima city, has enabled us to develop and apply techniques in construction and maintenance works focused on controlling of the vertical undermining of riverbeds and the erosion of margins at river crossings and creeks crossed by the pipeline carrying NG and NGL. According to the above, a technical assessment study was conducted of the crosses rivers and creeks that have high priority of the Camisea pipeline path, comprising — among other disciplines — hydraulic and undermining analysis, as well as an hydrologic and geo-morphological evaluation and other issues regarding general geology and geo-techniques at each crossing site.
A work program was developed using the information obtained in the three sectors travelled by the (STD) in order to develop and complement works at the crossings of rivers and valleys aiming to protect the integrity of the pipeline from erosion produced by major and extraordinary floods in riverbeds and alluvial slides in narrow valleys, by means of confinement and sedimentation works.
The jobs performed in rainforest, mountain and coastal terrain crossed by the pipeline considered different river morphology types — being the most common the straight, gravel braided and curved river travels — and regimes in both flow speed and width of the riverbed.
From the topographic follow-up and monitoring stage on — before and after the rain season — at crossings beneath the riverbeds, it was determined that the deterioration process affecting the crossing stripe corresponds to erosion consisting in the alteration of the watercourse banks that affects the piping foundations.
The works are completed considering the type of resources available at the site of the river crossing — i. e., the engineering is particular to each sector, and designing is performed upon available materials in the area.
The most utilized works at river and creeks crossings on the Camisea piping system are as follows: i) protection of riverbeds and creeks slopes using gabion mesh and pads; ii) sedimentation systems on gabion mesh; iii) Energy dissipation devices at creeks crossings; iv) rip-rap–type armoring of riverbeds; v) confinement check dams; vi) marginal protection dikes; vii) marginal protection rock fill dams; viii) protection and sedimentation breakwaters, among others.