Dry risk assessment for Northern Territory bores

Index:

Metadata
Citation
Description

Dataset Status
Data Quality
Contact Information
Data Dictionary
Supplementary Information

Metadata Details:

Name:AS/NZS ISO 19115 Geographic Information - Metadata, ANZLIC Metadata Profile

Version:1.0

Date Metadata Extracted:2025-07-04

Date Metadata Last Updated:2020-07-07

Current URL (HTML format) : http://www.ntlis.nt.gov.au/metadata/export_data?type=html&metadata_id=88BDA4371B57E694E050CD9B2144341B

Current URL (XML format) : http://www.ntlis.nt.gov.au/metadata/export_data?type=xml&metadata_id=88BDA4371B57E694E050CD9B2144341B

Citation

ANZLIC Identifier:88BDA4371B57E694E050CD9B2144341B

Title: Dry risk assessment for Northern Territory bores

Citation Date:2019-04-08

Date Type:creation

Custodian:Department of Environment, Parks and Water Security

Description

Abstract:

This point spatial dataset provides a predictive assessment for all registered bores in the Darwin Rural and Palmerston areas and the Katherine Tindall Limestone Aquifer (unconfined) as at 22nd April 2020 * to determine which bores might be at risk of going dry by 31st October 2020.
*All current registered bores that had been entered into NT Bores database by the 10 January 2020.

The 2019 / 2020 wet year produced below average rainfall in parts of the Top End following the second lowest Wet season in 2018/2019. This has produced inadequate recharge to groundwater levels in some areas.

Information for the dry risk assessment is described in the Help stop the drop web site denr.nt.gov.au/water/water-resources/help-stop-the-drop

Dry Risk Assessment Ratings:
- Green: Not at risk
- Orange: Potentially at risk
- Red: At risk
- Purple: Risk not determined
- Blue: Bore not assessed

KNOW YOUR BORE (mobile web mapping tool) denr.nt.gov.au/water/water-resources/help-stop-the-drop
This tool shows all NT registered bores displayed using the dry risk assessment ratings.
Step 1. Enter an address or registered bore number. (e.g. RNRN035972)
Step 2. Hover over a bore to view details.

NR MAPS (desktop web mapping tool) nrmaps.nt.gov.au
The data is displayed in NR Maps as layer name Bores with Dry Risk, located in folder Water, subfolder Bores.

How to find Dry Risk ratings for a bore using NR Maps:
- Select the layer, Bores with Dry Risk
- Right mouse click and Set Active
- Select a bore on the map screen
- View bore details in the data panel (below the map screen)

The Dry Risk Rating details have also been added to the NT Registered Bores dataset displayed in NR Maps.

ANZLIC Search Words:

environment

inlandWaters

Spatial Domain:

Bounding Coordinates:

North Bounding Coordinate:-12.14312

South Bounding Coordinate:-12.97764668

East Bounding Coordinate:131.39613052

West Bounding Coordinate:130.544598

Dataset Status

Dataset ID:

Language:English

Character Set: Latin 1

Progress:completed

Maintenance and Update Frequency:notPlanned

Data Currency Start Date:2019-04-08

Data Currency End Date:2020-06-06

Access Constraint:Download the Bores spatial data package (contains spatial data, maps and reports) via data.nt.gov.au/

You are licensed to use the DENR geospatial products on the terms and conditions set out in: Creative Commons Attribution 4.0 International Public License (CC BY 4.0) at: creativecommons.org/licenses/by/4.0/legalcode
If you do not agree to the terms and conditions you must not use the geospatial products.
You are free to copy, communicate and adapt the licensed material, provided that you abide by the licence terms (including Attribution) and attribute the licensed material using the statement:
Supplied by the Department of Environment and Natural Resources. Copyright Northern Territory Government.

Data Quality

Lineage:Version 1. Bores assessed as at 8th April 2019 in Darwin Rural Groundwater Resource Zones including Palmerston.
Version 2. Bores assessed as at 22nd April 2020 in Darwin Rural Groundwater Resource Zones including Palmerston and also the Katherine Tindall Limestone Aquifer (unconfined) within the Katherine Water Allocation Plan area.

Additional data used in the assessment included:
- SRTM 1s elevation data
- Modelled groundwater level data:
- Casing data from the former Hydstra database
- Groundwater monitoring data stored in the DENR Aquarius data base
- Darwin rural groundwater resource zones
- Darwin rural water control district boundary
- Katherine Tindall Water Allocation Plan
- Daly Basin Aquifers 1:250,000: Unconfined Katherine Tindall Limestone

ESRI ArcGIS 10.6 desktop was used to undertake the analysis.

Positional Accuracy:The Darwin area project extent is defined by the Darwin Rural Water Control Zones, bounded by the Darwin Rural Water Control District and includes Palmerston. The spatial datasets used to create the groundwater resource zones are varied in scale, ranging from 1:100 000 to 1:250 000.
The Katherine area project extent is defined by the unconfined Katherine Tindall Limestone Aquifer within the Katherine Water Allocation Plan area.

The location of bores is derived from the driller at the time of drilling.
Before 1995 - the positional accuracy of sites is will range between 300 - 10 000 metres.
After 1995 - with the use of GPS, the positional accuracy of sites improved to range between 3 - 10 metres.

If the bore location is incorrect, please contact Water Resources via email waterresources@nt.gov.au

Attribute Accuracy:Following the assessment, each bore point within the project areas has been assigned a class and a risk rating which are described in the Data Dictionary of this record.
The attribute vales are current as at 22nd April 2020.

Logical Consistency:Not applicable.

Completeness:The risk rating is current as at 22nd April 2020.

Contacts

Name Organisation Position Role Phone Fax Email

Data Requests Officer Department of Environment, Parks and Water Security Geospatial Services Branch (on behalf of department) distributor datarequests.depws@nt.gov.au

Name	Organisation	Position	Role	Phone	Fax	Email
Data Requests Officer	Department of Environment, Parks and Water Security	Geospatial Services Branch (on behalf of department)	distributor			datarequests.depws@nt.gov.au

Data Dictionary

Attribute Attribute Description Possible Code Code Description

01. BORE_NO Alias: Bore number
The registered bore number as per the NT Bores data set. This number must be in the following format 'RN035972'.

02. DRY_RISK Alias: Rating for risk of dry bore
The risk of the predicted groundwater level at 31 October 2020 being lower than the bore's assessment depth (cut off depth). At risk (red) Where the predicted groundwater level is below the 'cut-off' depth. This rating applies to areas where predicted groundwater levels were made with a PASTAs model.

Bore not assessed (blue) Bores outside of the project assessment areas OR bores entered into the NT Bores data base after the 22 April 2020. The Katherine Dry Risk Assessment relates only to bores located within the Katherine Tindall Water Allocation Plan area (KTWAP) AND which are drilled into the Katherine Tindall Limestone Aquifer. Other bores in the KTWAP area - which are not a Risk Class 4 *, access groundwater from other aquifers. These bores are described as Not Assessed. * All class 4 bores in the KTWAP area have been classed as Risk not determined.

Not at risk (green) Where the predicted groundwater level is below the 'cut-off' depth. This rating only applies to bores where a 'function' type prediction is used to estimate the end of Dry season groundwater level.

Potentially at risk (orange) Where the predicted groundwater level is below the 'cut-off' depth. This rating applies only to bores outside of Berry Springs and Howard groundwater systems because of low confidence in predicted groundwater levels.

Risk not determined (purple) Bores within the project assessment area with insufficient casing data to set a 'cut-off' depth.

03. OWNER_INFO Alias: Bore Owner Action (project information link)
Information for Darwin Rural residents is described here;
denr.nt.gov.au/land-resource-management/water/water-resources/help-stop-the-drop

04. RISK_CLASS Alias: Bore risk class
The criteria from the casing table of the former Hydstra data base used to determine the 'cut-off' depth for each bore.

DD - The drill depth is the total depth to which the bore was drilled.

CD - The construction depth is the depth to which a casing is installed. A casing is the pipe that is installed into the drill hole to hold water.
1 Summary: A class 1 bore contains casing data: drill depth, constructed depth, depth location of screens / slots Detail: A bore that contains at least one interval of screened casing. The 'cut-off' depth is set to 10m above top of screened interval (in metres AHD) for Darwin area bores. The 'cut-off' depth is set at 5m above screened interval (metres AHD) for Katherine area bores. If there is more than one screened interval, the top of the lowest screened interval is used.

2 Summary: A class 2 bore contains casing data for drill depth and construction depth only, where CD > 10m. No record of a screened interval. Detail: The 'cut-off' depth is set at CD+10 mAHD for Darwin bores and CD+5 mAHD for Katherine area bores.

3 Summary: No construction data, but DD>0. Detail: The 'cut-off' depth is set to DD+10metres in mAHD.

4 Summary: A class 4 bores is one where the construction depth and drill depth is not known. Detail: CD = 0 and DD = 0. A 'cut-off' depth cannot be determined.

05. ASSESSYEAR Alias: Date of Assessment
22nd April 2020

06. GWRESOURCE Alias: Darwin Rural Groundwater Resource
This is a combination of Groundwater System, Sub-Catchment and Sub group names.

This refers to the layer displayed in NR Maps called Darwin Rural Groundwater Systems. See folder Water, sub-folder Water Management.

Attribute	Attribute Description	Possible Code	Code Description
01. BORE_NO	Alias: Bore number The registered bore number as per the NT Bores data set. This number must be in the following format 'RN035972'.
02. DRY_RISK	Alias: Rating for risk of dry bore The risk of the predicted groundwater level at 31 October 2020 being lower than the bore's assessment depth (cut off depth).	At risk (red)	Where the predicted groundwater level is below the 'cut-off' depth. This rating applies to areas where predicted groundwater levels were made with a PASTAs model.
		Bore not assessed (blue)	Bores outside of the project assessment areas OR bores entered into the NT Bores data base after the 22 April 2020. The Katherine Dry Risk Assessment relates only to bores located within the Katherine Tindall Water Allocation Plan area (KTWAP) AND which are drilled into the Katherine Tindall Limestone Aquifer. Other bores in the KTWAP area - which are not a Risk Class 4 , access groundwater from other aquifers. These bores are described as Not Assessed. All class 4 bores in the KTWAP area have been classed as Risk not determined.
		Not at risk (green)	Where the predicted groundwater level is below the 'cut-off' depth. This rating only applies to bores where a 'function' type prediction is used to estimate the end of Dry season groundwater level.
		Potentially at risk (orange)	Where the predicted groundwater level is below the 'cut-off' depth. This rating applies only to bores outside of Berry Springs and Howard groundwater systems because of low confidence in predicted groundwater levels.
		Risk not determined (purple)	Bores within the project assessment area with insufficient casing data to set a 'cut-off' depth.
03. OWNER_INFO	Alias: Bore Owner Action (project information link) Information for Darwin Rural residents is described here; denr.nt.gov.au/land-resource-management/water/water-resources/help-stop-the-drop
04. RISK_CLASS	Alias: Bore risk class The criteria from the casing table of the former Hydstra data base used to determine the 'cut-off' depth for each bore. DD - The drill depth is the total depth to which the bore was drilled. CD - The construction depth is the depth to which a casing is installed. A casing is the pipe that is installed into the drill hole to hold water.	1	Summary: A class 1 bore contains casing data: drill depth, constructed depth, depth location of screens / slots Detail: A bore that contains at least one interval of screened casing. The 'cut-off' depth is set to 10m above top of screened interval (in metres AHD) for Darwin area bores. The 'cut-off' depth is set at 5m above screened interval (metres AHD) for Katherine area bores. If there is more than one screened interval, the top of the lowest screened interval is used.
		2	Summary: A class 2 bore contains casing data for drill depth and construction depth only, where CD > 10m. No record of a screened interval. Detail: The 'cut-off' depth is set at CD+10 mAHD for Darwin bores and CD+5 mAHD for Katherine area bores.
		3	Summary: No construction data, but DD>0. Detail: The 'cut-off' depth is set to DD+10metres in mAHD.
		4	Summary: A class 4 bores is one where the construction depth and drill depth is not known. Detail: CD = 0 and DD = 0. A 'cut-off' depth cannot be determined.
05. ASSESSYEAR	Alias: Date of Assessment 22nd April 2020
06. GWRESOURCE	Alias: Darwin Rural Groundwater Resource This is a combination of Groundwater System, Sub-Catchment and Sub group names. This refers to the layer displayed in NR Maps called Darwin Rural Groundwater Systems. See folder Water, sub-folder Water Management.

Supplementary Information

Information about the dry risk assessment is described in the Help stop the drop web site - denr.nt.gov.au/water/water-resources/help-stop-the-drop

Darwin Rural Groundwater Resource Zones. Refer to metadata record:
www.ntlis.nt.gov.au/metadata/export_data?type=html&metadata_id=61E80FB43D523BE6E050CD9B21445ED2

NT Registered Bores. Refer to metadata record:
www.ntlis.nt.gov.au/metadata/export_data?type=html&metadata_id=2DBCB7711FC106B6E040CD9B0F274EFE

Short, M.A. (2020).
Northern Territory Top End Groundwater Projections 2020: Darwin Rural Area.
Department of Environment and Natural Resources, Northern Territory Government, Palmerston.

Short, M.A. (2020).
Northern Territory Top End Groundwater Projections 2020: Tindall Limestone Aquifer.
Department of Environment and Natural Resources, Northern Territory Government, Palmerston.

This record maintained using the NTLIS Metadata Tool

Metadata : Dry risk assessment for Northern Territory bores