The geotechnical report is of utmost importance to the division in its review of the design. In the geotechnical report, the design engineer should demonstrate that the proposed dam site is adequate for the structure. The geotechnical report should contain the following information (NAC 535.210(4))
- Surface conditions of both the foundation area and of the borrow area
- Strength parameters of foundation and embankment material.
- Permeability of foundation and embankment material.
- Grain size distribution and classification of all materials used.
- Identify potential geological hazards, i.e. faults or voids.
- Boring and test pit results. The locations of the borings and test pit locations should be located on the drawings. The total depth of the borings and the lithology should be detailed in the report.
- Depth to water in the foundation and reservoir area.
- Availability of material.
- Soil properties of core, drain, filter and shell material including optimum moisture content.
- Expected settlement of the embankment and foundation.