Hydrogeology of the Australian Capital Territory and environs  

Authors / CoAuthors

Evans, W.R.

Abstract

The report and map synthesise groundwater studies made since 1954. Analysis of hydrogeological data defines the distribution of bore yield and groundwater chemistry for the regional aquifers of the ACT and environs. The aquifers are composed of fractured sedimentary, volcanic, and igneous rocks, and limited unconsolidated sediments in several different physiographic settings. Analysis of data, based on a three-way geological, 'broad-physiographic', and 'local-landform' subdivision scheme, shows that for bore yield, only the 'local-landform' parameter shows consistent relationships: in a given geomorphic unit, hill-crest bores always have lower yields than valley-floor or hill-slope bores. The highest mean yields are obtained from valley-floor bores tapping fractured aquifers in Ordovician to Early Silurian sedimentary rocks on the Cullarin Tableland. Groundwater yield is mostly obtained from the top 40 m of bores, and boreholes deeper than 100 m failed to improve yields. Groundwaters are generally dilute - less than 1200 mglL total dissolved salts. The variation in solute concentration is attributable to the geochemistry of the aquifer, the dissolution of soluble salts in the unsaturated zone of recharge areas, and the residence time of water in the aquifer. The better-quality water is found in aquifers that are geochemically stable, under high hydraulic gradients, close to recharge zones.

Product Type

document

eCat Id

15184

Contact for the resource

Keywords

• GA PublicationReport

( Theme )

• hydrogeology

• AU-ACT

Australian and New Zealand Standard Research Classification (ANZSRC)

• Earth Sciences

• Published_External

Publication Date

1987-01-01T00:00:00

Creation Date

Security Constraints

Australian Government Security ClassificationSystem    

Classification - unclassified

Legal Constraints

Creative Commons Attribution 4.0 International Licence    

Access - license

Use - license

Status

Purpose

Maintenance Information

unknown

Topic Category

geoscientificInformation

Series Information

Report 263

Lineage

Unknown

Parent Information

Extents

[-36.0, -35.0, 148.5, 149.5]

Reference System

Spatial Resolution

Service Information

Associations

Downloads and Links

File download  

Report (pdf)  

Source Information

Source data not available.