Evaluation of the impacts of deep open drains on groundwater levels in the wheatbelt of Western Australia
Riasat Ali A C , Tom Hatton A , Richard George B , John Byrne A and Geoff Hodgson AA CSIRO Land and Water, Private Bag 5, PO Wembley, WA 6913, Australia.
B Department of Agriculture, PO Box 1231, Bunbury, WA 6231, Australia.
C Corresponding author. Email: riasat.ali@csiro.au
Australian Journal of Agricultural Research 55(11) 1159-1171 https://doi.org/10.1071/AR04068
Submitted: 23 March 2004 Accepted: 11 October 2004 Published: 26 November 2004
Abstract
Abstract. Over one million hectares of the wheatbelt of Western Australia (WA) are affected by secondary salinisation and this area is expected to increase to between 3 and 5 million hectares if current trends continue. Deep open drains, as an engineering solution to dryland salinity, have been promoted over the past few decades; however, the results of initial experiments were variable and no thorough analysis has been done. This research quantifies the effects of deep open drains on shallow and deep groundwater at farm and subcatchment level.
Analysis of rainfall data showed that the only dry year (below average rainfall) after the construction of drainage in the Narembeen area of WA (in 1998 and 1999) was 2002. The dry year caused some decline in groundwater levels in the undrained areas but had no significant impact in the drained areas. The study found that the effect of drains on the groundwater levels was particularly significant if the initial water levels were well above the drain bed level, permeable materials were encountered, and drain depth was adequate (2.0–3.0 m). Visual observations and evidence derived from this study area suggested that if the drain depth cut through more permeable, macropore-dominated siliceous and ferruginous hardpans, which exist 1.5–3 m from the soil surface, its efficiency exceeded that predicted by simple drainage theory based on bulk soil texture. The effect of drains often extended to distances away (>200 m) from the drain. Immediately following construction, drains had a high discharge rate until a new hydrologic equilibrium was reached. After equilibrium, flow largely comprised regional groundwater discharge and was supplemented by quick responses driven by rainfall recharge. Comparison between the hydrology of the drained and undrained areas in the Wakeman subcatchment showed that, in the valley floors of the drained areas, the water levels fluctuated mainly between 1.5 and 2.5 m of the soil surface during most of the year. In the valley floors of the undrained areas, they fluctuated between 0 and 1 m of the soil surface. The impact of an extreme rainfall event (or unusual wet season) on drain performance was predicted to vary with distance from the drain. Within 100 m from the drain, water levels declined relatively quickly, whereas it took a year before the water levels at 200–300 m away from the drain responded. The main guidelines that can be recommended based on the results from this study are the drain depth and importance of ferricrete layer. In order to be effective, a drain should be more than 2 m deep and it should cut through the ferricrete layer that exists in many landscapes in the wheatbelt.
Additional keywords: shallow watertables, dryland salinity, engineering intervention, drainage impacts, waterlogging.
Acknowledgments
This work was supported by a grant from the Grains Research and Development Corporation, in partnership between Agriculture Western Australia and the Commonwealth Scientific Industrial Research Organisation. The authors thank the Hall, Latham, Deluise, Pini, and Bailey families for hosting this work on their properties and for logistical support. The authors also thank Mr Shahzad Ghauri of the department of Agriculture Western Australia for supplying water level data of south-eastern Hyden bores.
Ali R, Coles NA
(2001) Drainage options and their use in wheatbelt landscapes in Western Australia. ‘Proceedings of the Wheatbelt Valleys Conference’. (Water and Rivers Commission: Perth, W. Aust.)
Berhane D
(1999) Progress report on the performance of agricultural drainage in the Belka Valley. Agriculture Western Australia, Technical Report.
Bettenay E
(1978) Deep drainage as a method for treating saltland. Journal of Agriculture, Western Australia 19, 110–111.
Bettenay E,
Blackmore AV, Hingston FJ
(1964) Aspects of the hydrologic cycle and related salinity in the Belka Valley, Western Australia. Australian Journal of Soil Research 2, 187–210.
Bettenay E, Hingston FJ
(1961) The soils and land use of the Merredin area, Western Australia. CSIRO Division of Soils and Land Use Series No. 41.
Chin RJ
(1999) 1 : 250000 Geological series—Explanatory Notes, Kellerberrin, Western Australia. Geological Survey of Western Australia, Vol. Sheet SH 50-15, pp. 1–21.
Coles NA, George RJ, Bathgate AD
(1999) An assessment of the efficacy of deep drains construction in the wheatbelt of Western Australia. Miscellaneous Bulletin 4391, Agriculture Western Australia.
Cox JW, McFarlane DJ
(1995) The causes of waterlogging in shallow soils and their drainage in south-western Australia. Journal of Hydrology 167, 175–194.
| Crossref | GoogleScholarGoogle Scholar |
De Zeeuw JW, Hellinga F
(1958) Neerslag en afvoer. Landbouwkundig Tijdschrift [in Dutch with English summary]. 70, 405–422.
Ferdowsian R, George R, Lewis F, McFarlane D, Short R, Speed R
(1996) The extent of dryland salinity in Western Australia. ‘Proceedings 4th National Conference and Workshop on the Productive Use and Rehabilitation of Saline Lands’. (Promaco Conventions Pty Ltd: Perth, W. Aust.)
Ferdowsian R, Ryder A, Kelley J
(1997) Evaluation of deep drains in the North Stirling area. Agriculture Western Australia Technical Report No. 161.
George PR
(1991) Review of subsurface drainage for saltland reclamation. Department of Agriculture, Western Australia, Division of Resource Management Technical Report.
George RJ,
Clarke CJ, Hatton TJ
(2001) Computer modelled groundwater response to recharge management for dryland salinity control in Western Australia. Environmental Monitoring and Modelling
, 3–35.
George RJ, Frantom PWC
(1990) Using pumps and siphons to control salinity at a saline seep in the Wallatin Creek Catchment. Western Australian Department of Agriculture Division of Resource Management Technical Report No. 91, Perth.
George RJ,
Nulsen RA,
Ferdowsian R, Raper GP
(1999) Interactions between trees and groundwaters in recharge and discharge areas—a survey of Western Australian sites. Agricultural Water Management 39, 91–113.
| Crossref | GoogleScholarGoogle Scholar |
Hatton TJ, Nulsen RA
(1999) Towards achieving functional ecosystem mimicry with respect to water cycling in southern Australian agriculture. Agroforestry Systems 45, 203–214.
| Crossref | GoogleScholarGoogle Scholar |
Hatton TJ, Salama RB
(1999) Is it feasible to restore the rivers of the Western Australian wheatbelt? ‘Proceedings 2nd Australian Stream Management Conference, Adelaide’. (CRC for Catchment Hydrology: Clayton, Vic.)
Hatton TJ, Wu H
(1995) A scaling theory to extrapolate individual tree use to stand water use. Hydrological Processes 9, 527–540.
Luke JP
(2000) Review of drainage and surface water management in farming areas. Unpublished Draft Report, Water and Rivers Commission, Western Australia.
McFarlane DJ, Engel R, Ryder AT
(1989) The location of recharge areas responsible for valley salinity in the lake Toolibin catchment, Western Australia. ‘Groundwater recharge’. (Ed. ML Sharma)
pp. 255–267. (A.A. Balkema: Rotterdam)
McFarlane DJ, Wheaton GA, Negus TR, Wallace JF
(1992) Effects of waterlogging on crop growth and pasture production in the upper great Southern, Western Australia. Technical Bulletin No. 86, Agriculture Western Australia.
Nott R
(2001) Groundwater study of the Narembeen townsite. Resource Management Technical Report No. 216, Department of Agriculture Western Australia.
Nulsen RA
(1983) Review of current drainage investigations in Western Australia. Natural Resources Management Technical Report No. 8, Department of Agriculture, Western Australia.
Otto C, Salama RB
(1994) Linked enhanced discharge—evaporative disposal systems. ‘Groundwater—drought, pollution and management’. (Eds R Reeve, J Watts)
pp. 35–44. (A.A. Balkema: Rotterdam)
Ritzema HP
(1994) Subsurface flow to drains. ‘Drainage principles and applications’. pp. 263–304. (International Institute for Land Reclamation and Improvement: Wageningen, The Netherlands)
Salama RB,
Bartle GA,
Farrington P, Wilson V
(1994) Basin geomorphological controls on mechanism of recharge and discharge and its effect on salt storage and mobilisation—comparative study using geophysical surveys. Journal of Hydrology 155, 1–26.
| Crossref | GoogleScholarGoogle Scholar |
Speed RJ, Simons JA
(1992) Deep drains—a case study and discussion. Technical Report No. 133, Department of Agriculture, Western Australia.
Wood WE
(1924) Increase of salt in soil and streams following the destruction of the native vegetation. Journal of the Royal Society of Western Australia 10, 35–47.
