Electronic Data Collection and Analysis System
Yin Foo, Des; Foley, Margaret
E-Publications; PublicationNT; E-Books; Report ; 39/1992
1992-08-01
Made available via the Publications (Legal Deposit) Act 2004 (NT).
Date:1992-08
English
Power and Water Authority
Darwin
Report ; 39/1992
application/pdf.
Check within Publication or with content Publisher.
https://hdl.handle.net/10070/229024
https://hdl.handle.net/10070/673447
Technical Report WRD92039 Viewed at 15:07:17 on 29/07/2010 Page 169 of 192. Dl. CO}TVERTING LOGGED HEAD TO DRAWDOWN ~later level data which was logged in terms of "head" (Le. the depth of water above the transducer) may need to be converted to d:awdown (i.e. change in water level compared to that at some pe;rticular time). If the head at the time TO is HO I then the drawdown at any time compared to HO is : DD = HO - H (1 ) i.e. the drawdown at any time is found by subtracting the head at that time fr-om the head at time TO. A fall in water level is therefore calculated as a positive drawdown. "DATMAN" provides a facility to subtract a constant from a complete data set I which can be used if (1) above is revlritten as : DD - -(H - HO) = (H-HO) * -1 l'herefore the procedure to perform the conversion is to subtract HO from the entire data set, and to then multiply the set by -1. See example 4. 2 belO\~.