Hydraulic conductivity is one of the most variable and yet an essential parameter in environmental engineering, in estimation of contaminant travel time in soils and groundwater. Also, it is one of the most difficult parameters to determine, and directly affects the quantity of water that will flow. Hydraulic methods for estimation the hydraulic conductivity can be either laboratory methods or in-situ methods. This study presents five laboratory methods which can be used to estimate the hydraulic conductivity of soils: variable-head permeameter - Kamenski; simplified permeameter; constant-head Cromer permeameter, in two working configurations; constant-head permeameter connected to piezometric tubes and a variable-head permeameter. Although these methods require more labour than other available methods, e.g. the correlation methods, they are relatively fast and not expensive. For the porous material used in the experiments, the most accurate values of the hydraulic conductivities were obtained with the constant-head permeameter connected to piezometric tubes.

Large hydropower developments are not considered to be environmentally friendly due to large landscape flooded by their reservoirs. There is a certain carbon footprint related to this, in the phase of construction and of the operation of the reservoirs. This paper presents GHG emissions related to an iconic reservoir from Romania, Vidraru, and demonstrate that values are close to those determined around the world and that comparing with other conventional power plants producing electricity is the best environmental option. Furthermore, must be considered the other water uses related to reservoirs as flood mitigation, water supply for population, irrigation, and industry, where reservoirs cannot be replaced by anything else.