Territory Stories

Development of a Groundwater Model for the Western Davenport Plains

Details:

Title

Development of a Groundwater Model for the Western Davenport Plains

Creator

Knapton, Anthony; CloudGMS Pty Ltd

Commissioned by

Northern Territory. Department of Environment, Parks and Water Security

Collection

E-Publications; E-Books; PublicationNT; WRD Technical Report 27/2017

Date

2018-03

Location

Western Davenport Water Control District

Abstract

CloudGMS has been commissioned by DENR to develop a numerical groundwater model of the aquifers within the central area of the WDWCD to improve confidence in the sustainability of the groundwater resources, as this is the area within the WCD with greatest potential for intensive development.

Notes

Made available by via Publications (Legal Deposit) Act 2004 (NT); Prepared for Dept Environment and Natural resources

Table of contents

Executive summary -- 1 Background -- 2 Physical -- 3 Available data -- 4 Conceptual model -- 5 Model design & construction -- 6 Parameter estimation -- 7 Water balances -- 8 Sensitivity analysis -- 9 Predictive scenarios -- 10 Conclusions -- 11 Reference -- 12 Document history and version control -- Appendix A - Groundwater level hydrographs - Appendix B - Alek range horticultural farm sub-regional modelling

Language

English

Subject

Groundwater; Northern Territory; Western Davenport Water Control District; Conceptual mode

Publisher name

Northern Territory Governmnet

Place of publication

Palmerston

Edition

version 2.0

Series

WRD Technical Report 27/2017

Format

ix, 127 pages : colour illustration and maps ; 30 cm

File type

application/pdf

ISBN

9781743502976

Use

Attribution International 4.0 (CC BY 4.0)

Copyright owner

Northern Territory Government

License

https://creativecommons.org/licenses/by/4.0/

Related links

https://hdl.handle.net/10070/842058 [LANT E-Publications: Development of a Groundwater Model for the Western Davenport Plains, version 1.1]

Parent handle

https://hdl.handle.net/10070/858845

Citation address

https://hdl.handle.net/10070/858846

Page content

Western Davenport WCD Groundwater Model (v2.0) Contents CloudGMS vii Figure 3-14 RN018118 groundwater level hydrograph showing response to groundwater abstraction with simulated groundwater response. ...................................................................................... 39 Figure 3-15 Monthly extraction within the Western Davenport WCD for the period mid 2006 2016 (source DENR). .......................................................................................................................... 40 Figure 3-16 Distribution of production bores within the Western Davenport WCD. ........................... 41 Figure 3-17 Major vegetation classes (NVIS based on southern NT land systems mapping) with mapped wetland features after Duguid (2009). .......................................................................... 43 Figure 3-18 Average annual leaf area index for 2006 and 2007. ....................................................... 44 Figure 3-19 Average annual leaf area index for 2008 and 2009. ....................................................... 44 Figure 3-20 Average annual leaf area index for 2010 and 2011. ....................................................... 45 Figure 3-21 Average annual leaf area index for 2012 and 2013. ....................................................... 45 Figure 3-22 Average annual leaf area index for 2014 and 2015. ....................................................... 46 Figure 3-23 Groundwater dependent vegetation monitoring sites identified by DENR. ...................... 47 Figure 4-1 Modelled hydrological components and their interactions in the Western Davenport WCD study area. ................................................................................................................................ 50 Figure 4-2 Simplified conceptualisation of the processes influencing recharge. ................................ 51 Figure 5-1 Schematic of the processes in MIKE SHE, including the available numeric engines for each process. The arrows show the available exchange pathways for water between modules (Graham and Butts, 2005). ...................................................................................................................... 56 Figure 5-2 SILO data drill daily climatic data a) rainfall and b) evaporation. ........................................ 58 Figure 5-3 Layer lower level elevations in metres AHD a) Layer 1 (base of Cenozoic sediments) and b) Layer 2 (base of the Dulcie Sandstone and Lake Surprise Sandstone). ...................................... 60 Figure 5-4 Layer lower level elevations in metres AHD a) Layer 3 (base of the Arrinthrunga Fm.) and b) Layer 4 (base of Chabalowe Fm.). ............................................................................................. 60 Figure 5-5 Model extent and external boundary conditions. Red cells are no-flow boundary conditions, yellow cells are active and green cells are external boundary conditions. ................. 62 Figure 5-6 Infiltration zones used to delineate recharge to the groundwater system. ........................ 64 Figure 5-7 Diagrammatic representation of the UZ process model with profiles comprising 2 soil types. ........................................................................................................................................ 70 Figure 5-8 Grid codes (zones) defining the spatial distribution of soil profiles used in the unsaturated flow process model. .................................................................................................................. 71 Figure 5-9 Geological unit distributions for each layer a) Layer 1 Cenozoic; b) Layer 2 Dulcie; c) Layer 3 Arrinthrunga; and d) Layer 4 Chabalowe. ................................................................. 74 Figure 6-1 Estimated steady state infiltration rate distribution [mm/d]. .............................................. 79 Figure 6-2 Calibrated root depth in metres below ground level ......................................................... 80 Figure 6-3 Scatter plot of calibrated steady state heads at available observation bores. aileron = aileron province to the southwest davenport = davenport ranges province to the northeast georgina = southeast central zone in the georgina basin wiso = northwest central zone in the wiso basin ......................................................................................................................................... 81 Figure 6-4 Western Davenport WCD calibrated steady state head contours. .................................... 82 Figure 6-5 Monthly groundwater extraction for the period 1970-2015 source DENR (2016). ............ 85 Figure 6-6 Comparison between observed and simulated groundwater levels at a) RN005409 b) RN0018114 c) RN018118 and d) RN018404. ........................................................................... 88 Figure 7-1 Distribution of zones used to determine sub-catchment water balances in the WDWCD. 92 Figure 8-1 Relative sensitivity of objective function to parameter changes to a) parameters related to soil properties, b) parameters relating to saturated aquifer properties and c) parameters relating to vegetation water use. ................................................................................................................ 99 Figure 9-1 Cross-section centred on the pumping used in scenario SC4. The black lines are the surfaces of each layer and the blue line is the groundwater phreatic surface. ........................... 101 Figure 9-2 Groundwater levels at the end of the 45-year simulation for a) scenario SC3 and b) scenario SC4. .......................................................................................................................... 102 Figure 9-3 Extent and magnitude of groundwater drawdown for a) SC3 and b) SC4. ..................... 103