Unit for demonstrating the hydrological principles of groundwater flow and the applications of these to different engineering constructions. It allows the investigation of ground water flows, the drainage processes and the effect of the permeability. It is possible to study the use of wells, de-watering and drainage of lakes, and demonstration of ground drainage works, among others. Wells have a spillway in their upper part to avoid floods. xercises and Practical Possibilities”section) This unit allows a quick configuration of any easy situation of tridimensional flow and to measurement the piezometric levels at different and appropriate places within the model, making possible to obtain realistic experimental results. In addition to the demonstrations and exercises proposed (see “E , instructors and students may construct further model situations for study. The Ground Water Flow Unit (EFAS) is composed of a test tank that will be filled with fine grave or sand to construct to develop different models. The entry of water into the tank is done through two inlets, each of them located at each end. The flow of each water inlet is controlled by a membrane valve, which is easily accessible for the user. Inlets end inside the tank in a diffuser shape to affect the least possible the created model. In the base of the test tank there are two wells simmetrically located. The wells outlets, located at the bottom part of the tank, have a membrane valve, that allows the regulation of the outlet flows. The unit includes 19 tappings in the base of the test tank, configured in cross shape . Pressure of the 19 tappings can be seen in 2 manometers panels. The tappings have a sediments picking system to avoid them to reach the measuring elements. Under each tapping there is a plug which has to be removed regularly to extract the sand accumulated in it.
EFAS unit is supplied with three accessories that make it easy the construction of the different models object of study:
1.- Model for a lake construction.
2.- Model for an excavation construction.
3.- Model for a confined aquifer construction.
In addition to the demonstrations and exercises proposed (see “E , instructors and students may construct further model situations for study