Directorate:  Geohydrology

DATA AVAILABILITY AND QUALITY INDEX

AIM :

• Data Availability Index

The aim of the Data Availability Index of the Open-NGDB is to set up a comprehensive index of the data that is available on the system.

• Data Quality Index

The aim of the Data Quality Index of the Open-NGDB is to set up a comprehensive index of the quality of the data stored in the system.

This comprehensive metadata will be kept for each borehole. The Data Availability and Quality Indeces will also be a tool to facilitate querying in SQL, GIS, Open-NGDB and NGA environment.

BUSINESS RULES :

• The Data Availability Index will be set up for each borehole/Site Id. and will contain 10 alphanumeric characters signifying various metadata.
• The Data Quality Index will be set up for each borehole/Site Id. and will contain 10 digits representing various meta data.

DATA AVAILABILITY AND QUALITY INDEX MATRIX

• Positions of codes are fixed.
• Note : "O" is an alpha character as opposed to a zero "0" in the Data Quality Index columns.
• The Data Quality Index will only indicate whether the Data Quality Audit has been complete for the relevant fields. (A ‘1’ will indicate that the Data Quality Audit has been complete and a ‘0’ will indicate that the Data Quality Audit has not been complete for the relevant fields.)

Explanation of the codes

COORDINATE METHOD

S – Surveyed (T in NGDB)

G – GPS

I – Interpolated from sketch (M in NGDB)

F – Farm name only (an accuracy of 4 in NGDB)

DEPTH OF BOREHOLE

O – No Depth of borehole available

D – Depth of borehole available

WATER LEVEL MEASUREMENT ( < than 50)

O – No water level measurement available

W – Water level measurement available (1-49)

SERIES OF WATER LEVEL MEASUREMENTS ( > or = 50)

O – No multiple (time series) water level measurements available

S – Multiple water level measurements available

GEOLOGY RECORD AVAILABLE

O – No Geology record available

L – Geology record available

YIELD

O – No yield available

Y – Yield available

PRIMARY DOCUMENTATION (site related)

O – No primary documentation for audit available

P – Primary documentation for audit available

CHEMICAL ANALYSIS

O – No Chemical analysis available

C – Chemical analysis available

CONSTRUCTION DETAILS

O – Any of BOREHOLE DIAMETER or CASING LENGTH is unavailable

N – Both BOREHOLE DIAMETER and CASING LENGTH are available

The following will be true if construction details are available :

• Depth of the borehole is available
• Diameter of borehole is available
• Borehole casing length is available 

WATER USE

O – Water use information is unavailable

U – Water use information is available.