Daly
17.12 Entitled diversion of allocated surface water to urban water system

Supporting information

The volume recognised in the water accounting statements (2,355 ML) represents the volume of water diverted for urban water supply in the Daly region during the 2011–12 year.

Total surface water diverted from each surface water resource for urban water supply in the Daly region during the 2011–12 year is given in the following table.


Volume of water diverted from each surface water resource for urban water supply during the 2011–12 year

Surface water resource

Water diverted (ML)

Katherine River—Katherine town supply1

2,355

Copperfield Creek—Pine Creek town supply

0

Total

2,355

1. Volume based on metered and estimated data (see 'Quantification approach')

Quantification approach

Data source

Water Resource Licensing database and meter readings from licensees.

Provided by

Department of Land Resource Management.

Method

The volume presented for this line item is a combination of metered data and estimates.

There are two separate licences for water supply to Katherine. The allocated diversion for one licence was based on metered data (approximately 98% of the volume) and the other was based on estimated data.

Where metered data are available, the abstraction is calculated as the actual abstraction during the 2011–12 year. Metered data are supplied to the Department of Land Resource Management on a monthly basis. Where metered data are not available, the volume of diversion is estimated to be the full annual allocation.

Assumptions, limitations, caveats and approximations

Less than 2% of the total volume of surface water diverted for Katherine supply was based on estimated data. The estimated abstraction is assumed to equal the full annual allocation, and that the rate of abstraction is uniform throughout the year. It is unlikely on both counts that this will be the case for this licence.

Uncertainty information

Expected error for water meters is +/– 2%.

The Department of Land Resource Management requires that all water meters, when tested under in situ conditions, must be within 2% accuracy across the full flow rate range. See the Department's Water meters fact sheet for more information.

For estimated data the uncertainty is unquantified.