JDC Electronic SA SalinoMADD - Manual (Page 14)

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MADD Technologies sàrl
– Avenue des Sports 42 – CH-1400 Yverdon-les-Bains – Switzerland
Tel: +41 24 445 31 16 – Fax: +41 24 445 21 23 – Email: [email protected] – www.madd.ch
T T i i p p s s f f o o r r p p r r a a c c t t i i c c a a l l u u s s e e
• Prepare, whenever possible, gauging site programming in advance. It makes the actual data acquisition
work much easier.
• Upon arrival at the measurement site, place immediately the probe into the water. It will then reach fast
the water temperature.
• Try to position the probe in a place where the water course is not too turbulent. Always avoid the
phenomenon of cavitation around the probe. It can perturb the measurements and cause air bubbles
between the probe's electrodes.
• Do not connect the probe to the SalinoMADD when switched on. If this happens however, the SalinoMADD
may be blocked and can not be switched on again. It is then necessary to remove the alkaline batteries for
a moment and put them back in place again. In this case, recorded data, date and time are lost. The unit is
still in working condition but names of sites, localities and operators can always be introduced later at the
office.
• Don’t forget that the SalinoMADD must record at least 100 measurements prior to the arrival of the salt
cloud. The time needed for these measurements is proportional to the gauging intervals as shown below:
INTERVAL RECORDING BEFORE CLOUD ARRIVES
1 second 1 minute 40 seconds
2 seconds 3 minutes 20 seconds
4 seconds 6 minutes 40 seconds
8 seconds 13 minutes 20 seconds
16 seconds 26 minutes 40 seconds
32 seconds 53 minutes 20 seconds
• It is preferable to dilute the salt in water taken from the river to be gauged and then inject the total mixed
solution at once into the water course (max. 300 g of salt per litre). Avoid not yet dissolved salt to sink to
the bottom of the riverbed.
• The most important point for successful gauging is in fact the good dissolution and mixture of the salt in
the water course. Some turbulences caused by a few stones or tiny waterfalls favours the mixing process.
In a straight and flat riverbed or a canal placing some stones can help the mix.
• Small side streams of the water course and basins may slow down part of the current which does not
favour the mixing process.
• A higher speed of the current is a positive factor for the mixing process and a rapid passage of the salt
cloud favours the measuring since the threshold of natural salinity varies very little.
• Gauging in tunnels, straight canals with a current speed of 1 meter/second gives good results even at long
distances (e.g. more than 3000 m) from point of salt injection.