Developed by CARPI

Waterproofing Specialists and Contractors with Geomembranes


The CARPI system is a patented system for waterproofing and draining the upstream face of all types of dams and providing protection from the deterioration phenomena caused by seepage of reservoir water into the structure.

The upstream face of Cignana dam, deteriorated by freezing and thawing cycles, before rehabilitation.

Primary Benefits of the CARPI System

  • Stop water seepage and deterioration
  • Restore impermeability of the deteriorated dam face
  • Reduce uplift in the dam body
  • Restore safety factors to original values
  • Dehydrate the dam body from infiltrating water
Cinaga 2
Cignana dam rehabilitated with CARPI system in 1988. The geomembrane system is still in full service.

The above benefits are achieved by installing a continuous impermeable barrier from the crest to the heel of the dam. The barrier can be connected with the foundations and the grout curtain. A continuous face drainage system installed between the barrier and the dam face collects and discharges the water from seepage and dehydration.

The CARPI system impermeable water barrier consists of an exposed flexible synthetic geocomposite (impervious geomembrane + anti-puncture geotextile). Linear anchorage of the geocomposite to the upstream face of the dam is made by mating pair of stainless steel vertical patented profiles.

Watertight perimeter anchorage avoids by-passing of the barrier by the reservoir water.

Since the entire surface of the geocomposite is not glued to the dam face, the system allows drainage of the seepage water and dehydration of the dam body from water that has already infiltrated. A perimeter collection system at the heel of the dam allows discharge of the drained water.

In the two figures below we present uplift diagrams for the traditional gravity dam with drains and with exposed CARPI drained geomembrane system.

Comparing Uplift

Illustr A Pag Concept
Uplift force diagram at section of dam without geomembrane
Illustr B Pag Concept
Uplift force diagram at section of dam with CARPI exposed drained geomembrane system

CARPI Drained System

Illustr C Pag Concept
Without new grouting beam
Illustr D Pag Concept
With new grouting beam

Typical cross sections

  • a) Dam body
  • b) CARPI waterproofing geocomposite
  • c) Vertical anchorage and face drainage for geocomposite
  • d) Perimeter drainage collection system
  • e) Perimeter seals
  • f) New grouting beam (if required)
  • g) Ventilation pipe
110902 RCCdams 3
110902 RCCdams 4

Detail at heel

  • h) Drainage discharge
  • i) Grouting curtain
  • j) Contact grouting
  • k) Inspection gallery
  • l) Dam drains