DENSITY CONTOUR OF THE WATER.

The density contour of the water plays an essential role in the choice of the optimal process for discharging gas-filled water and the estimation of the risk of a gas explosion. We have therefore concentrated on this area, on the one hand by taking measurements in the lake and on the other by suggesting a model of this phenomenon. The model introduces progressively the parameters which appear to be essential: temperature, content in dissolved ions, content in dissolved gas and hydrostatic pressure. The correspondent calculated contours are assembled in the following figure.

As well as this, we have made a series of measurements of water density obtained either by pumping or by auto-siphon at different depths, from the lake surface down to a depth of 400 m. Density is measured using an Anton Paar densitometer with a resolution of 10-4. Comparable accuracy can be obtained by crossing water samples with measurements of distilled water at a given temperature. Note that the temperature measurements have been obtained with a high quality thermometer with an accuracy of one-thousandth of a degree. The values obtained experimentally are in violet on the figure below.