Territory Stories

Development of a Groundwater Flow Model - Berry Springs

Details:

Title

Development of a Groundwater Flow Model - Berry Springs

Creator

Knapton, Anthony

Collection

E-Publications; E-Books; PublicationNT; 17/2016

Date

2016

Location

Berry Springs

Description

Made available via the Publications (Legal Deposit) Act 2004 (NT).

Table of contents

Table of Contents -- List of Figures -- List of Tables -- Acknowledgements -- Glossary of Terms -- Executive Summary -- 1 Introduction -- 1.1 Background -- 1.1 Aim of the study -- 2 Site Description -- 2.1 Study area location -- 2.2 Climate -- 2.2.1 Rainfall data -- 2.2.2 Evaporation data -- 2.3 Hydrology -- 2.4 Land use -- 2.5 Groundwater extraction -- 2.6 Water quality -- 3 Hydrogeology -- 3.1 Geological formations -- 3.1.1 Mount Bonnie Formation (Pso) -- 3.1.2 Unnamed Dolostone Unit (Psd): Berry Springs Dolostone -- 3.1.3 Burrell Creek Formation (Pfb) -- 3.1.4 Depot Creek Formation (Ptd) -- 3.1.5 Petrel Formation (JKp) -- 3.1.6 Darwin Member (Kld) -- 3.2 Geological structure -- 3.3 Aquifer characteristics -- 3.3.1 Hydraulic conductivity -- 3.3.2 Storage coefficient -- 4 Groundwater hydrology -- 4.1 Groundwater flow -- 4.2 Recharge -- 4.2.1 Water balance method -- 4.2.2 Water table fluctuation method -- 4.2.3 Spring discharge -- 4.2.4 Evapotranspiration -- 4.3 Rainfall-runoff modelling -- 4.4 Predicted natural conditions compared to recent observed flows -- 4.5 Groundwater chemistry -- 5 Available data -- 5.1 Climate data -- 5.2 SRTM digital terrain model -- 5.3 Geological data -- 5.4 Groundwater level data -- 5.4.1 Steady state groundwater levels -- Berry Springs Groundwater Flow Model -- 5.4.2 Time series groundwater levels -- 5.5 River discharge data -- 5.5.1 Manual gauging data -- 5.5.2 Continuous recorder data -- 5.6 Pumping data -- 5.7 Data gaps -- 6 Groundwater flow model development -- 6.1 What is a groundwater flow model? -- 6.2 Conceptual model -- 6.3 Modelling approach -- 6.4 Model package -- 6.5 Model mesh geometry -- 6.5.1 Mesh design -- 6.5.2 Mesh generation -- 6.6 Material properties -- 6.7 Fracture flow -- 6.8 Boundary conditions -- 6.8.1 Recharge and Areal ET Flux -- 6.8.2 Constant head BC values -- 6.9 Pumping data -- 6.10 FEFLOW settings -- 6.10.1 Problem class -- 6.10.2 Temporal and control data -- 7 Calibration -- 7.1 Steady state finite element model -- 7.1.1 Steady state model results -- 7.2 Transient finite element model -- 8 Scenarios -- 8.1 Water balance assessment -- 8.2 Scenario A – Historic climate without pumping -- 8.2.1 Water balance under historic climate -- 8.3 Scenario B – Historic climate with current pumping estimates -- 8.3.1 Pumping estimate methodology -- 8.3.2 Water balance under historic climate and current pumping -- 8.3.3 Impacts of pumping on groundwater discharge at Berry Springs -- 8.3.4 Flow duration -- 9 Results and discussion -- 9.1 Measurable impacts -- 9.1.1 Reduced dry season flows -- 9.1.2 Recession slope of dry season flows -- 9.1.3 Groundwater levels -- 9.2 Rainfall, recharge & minimum flows analysis -- 9.3 Impacts of pumping based on zones -- 10 Conclusions -- 10.1 Key performance indicators -- 11 References -- Appendix A - Groundwater level hydrographs -- Appendix B - Calibrated transient model results

Language

English

Subject

Berry Springs Dolostone; Berry Springs aquifer System; Groundwater Flow Model

Publisher name

Department of Land Resource Management

Place of publication

Darwin

Series

17/2016

Format

72 pages : colour illustration and maps ; 30 cm.

File type

application/pdf.

ISBN

9781743501092

Copyright owner

Check within Publication or with content Publisher.

Parent handle

https://hdl.handle.net/10070/272355

Citation address

https://hdl.handle.net/10070/428025

Page content

Berry Springs Groundwater Flow Model Page 6 of 72 Figure 25 Impact of pumping expressed as the percentage decrease from the modelled historic flows. ....................... 47 Figure 26 Flow duration curve demonstrating effects of pumping on the discharge to the Berry Springs spring complex. 48 Figure 27 Predicted heads for a) dry season - 8/12/2000 (36868d) and b) wet season - 27/04/2001 (37008d) .............. 50 Figure 28 Conceptualisation of Mike SHE modelling components. In this case the groundwater flow was modelled using FEFLOW. ...................................................................................................................................................................... 64 Figure 29 Input rainfall data to the MIKE SHE recharge model. ...................................................................................... 65 Figure 30 Input evaporation data (proxy for actual ET) to the MIKE SHE recharge model. ............................................. 65 Figure 31 Time series leaf area index (green line) determined from typical wet and dry season values of LAI (Hutley et al., 2001) and the soil moisture deficit model. Included is the root depth (red line). ................................................... 66 Figure 32 Comparison of cumulative recharge for 01/01/1900 to 1/01/2006 as determined by the SMD model (black line) and the Mike SHE model incorporating macro pore bypass (blue line). ............................................................... 67 Figure 33 Comparison between observed and simulated heads of the calibrated Berry Springs groundwater model. The simulated heads are evenly distribution either side of the 1:1 fit suggesting that errors are relatively random, although there appears to be an overestimation of heads greater than 15 mAHD. ..................................................... 70 Figure 34 Comparison between log transformed observed and simulated discharge for G8150027. ............................. 70 List of Tables Table 1 Areas of classified land uses in the Berry Springs area 15 Table 2 Average annual water balance components determined using NAM rainfall-runoff modelling. 25 Table 3 September 1994 groundwater levels used in the calibration of the steady state model 30 Table 4 Number of gaugings separated into each month with maximum and minimum flows recorded. 30 Table 5 Summary of pumping bore extraction data. 32 Table 6 Hydrogeological units relevant to the groundwater modelling study. 33 Table 7 Groundwater levels used for steady state calibration 41 Table 8 Calibrated aquifer parameters 42 Table 9 Water balance for 109.75 years of historic climate data for the Berry Springs groundwater model. 44 Table 10 Berry Springs groundwater model water balance for 109.75 years of historic climate data and current pumping estimates. 45 Table 11 Soil parameters used in the recharge model. 66 Table 12 Estimated parameter values determined from PEST process 69 Table 13 Parameter values used in the sensitivity analysis of the Berry Springs groundwater model 70 Acknowledgements This report was updated with support and technical assistance from CloudGMS Pty Ltd.


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