**2.2 Geotechnical results investigated on quaternary deposits**

A geotechnical investigation into quaternary deposits that have represented construction materials and dam foundation of Memve'ele dam is described in this topic. Many boreholes were drilled by drilling rig to assess the geotechnical of the quaternary deposits from borrow areas and in the dam foundation site. The investigation of three borrows areas and dam sites comprised mainly laboratory tests of soil deposits. The results of mechanical tests are presented in **Table 1**. The specific gravity values vary from 2.60 to 2.76; wet and dry densities are ranged from 1.51 to 1.61 g/cm3 and 1.23 to 1.55 g/cm3 respectively; porosity values vary between 0.700 and 1.190%; liquid limit values vary between 58.4 and 76.2 wt. %; plasticity limit values are ranged between 28.3 and 40.1 wt. %. The deformation modulus values vary between 1.9 and 9.9 MPa; the coefficient of permeability varies between 8.62E−04 and 3.35E−05 cm/s. As per the exploration well, the reserve estimations is 182.39 × 104 m3 . However, slope occurs with erosion marks (**Figure 5**) after raining seasons.
