Electronic Data Collection and Analysis System
Yin Foo, Des; Foley, Margaret
E-Publications; PublicationNT; E-Books; Report ; 39/1992
Made available via the Publications (Legal Deposit) Act 2004 (NT).
Power and Water Authority
Report ; 39/1992
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Technical Report WRD92039 Viewed at 15:07:17 on 29/07/2010 Page 162 of 192. C3 STANDARD IIRAWDOWN TEST C3.1 AIMS There may be some concern that the standard accuracy test results may Eot be replicated in a situation where the transducer iS3t a fixed depth and the water level is moving much more slowly than the probe movement speeds used in the standard accuracy test. The system may be tested in a set-up as described above (i.e. in a well whose standing Ivater level (SWL) is clearly visible), but with the water level varied by pumping. The pump should be outside the well if possible, and could cause as little vibration in the well as possible. C3.2 PROCEDURE lI..n accurate independent water level measurement lS essential - a freely moving and responsive "Float and tape" system, or other highly specified and proven device can be used. Another manual SWL measuring is desirable as a check, or a proven electronic system may be placed downhole and its' readings used ::or comparison. 'I'he system to be tested is set logging at a small logging period, and manual SWL readings taken at regular intervals. The system er;~or is calculated from the differences between logged and manual (or check system's) readings. C3.3 ANALYSIS ~'he analysis can be carried out as per C2. 3 above - i. e. , find the mean and standard of the errors calculated as the differences between logged data and manually collected data. Note that any recalibration required (as per C2. 3 from a standard accuracy test) or any necessary barometric correction