Predicting stream salinity changes in South-Western Australia

Loh, Ian; Stokes, R.A.

doi:10.1016/0378-3774(81)90052-4

Cited by 19 publications

(5 citation statements)

References 4 publications

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“…These methods have been more comprehensively documented elsewhere (Freeze and Cherry, 1979) and used in other groundwater salinity studies (Jenkin and Dyson, 1983). The specific yield technique (Johansson, 1987) was used as comparison to the groundwater balance technique, as other studies (Loh and Stokes, 1981;McFarlane et al, 1989) had found agreement between this method, and others used to estimate recharge. The vertical discharge technique (Domenico, 1971) was also employed to estimate groundwater discharge rates, using the hydraulic gradient and conductivity data assessed from the piezometers installed at the site.…”

Section: Groundwater Balance Estimatesmentioning

confidence: 99%

Interactions between perched and saprolite aquifers on a small, salt‐affected and deeply weathered hillslope

George¹,

Conacher

1993

Earth Surf Processes Landf

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A small hillslope was chosen to investigate the role of throughflow as a mechanism responsible for the movement of soil water and solutes towards a saline seep and as a source of recharge to a permanent, regional aquifer at depth. The hydraulic properties, chemical characteristics and physical responses of both systems were studied on a deeply weathered, salt-affected hillslope. Additional data were also obtained from other sites in south-western Australia.Regional groundwater flow occurred in a variably textured, deeply weathered material in which the hydraulic conductivity varied from < 0.001 to 0.14m day-'. Perched groundwater flow (throughflow) occurred in the higher permeability (-1.15 m day-' ), near-surface soil materials. Throughflow occurred throughout winter, contributing approximately 530 m3 of fresh (-160 mgl-' C1) water to a saline seep. By contrast, the deep aquifer discharged approximately 1100 m3 of waters with salt concentrations of 20006000 mgl-' C1. Recharge and discharge rates to and from the deep aquifer, were estimated to be of the order of 5-20 mm a -' and 5&300 mm a-' respectively.Saturated conditions existed throughout winter within the seep and the immediately adjacent non-saline area, with up to 60 per cent of the hillslope soils becoming saturated after major rainfall events ( > 20 mm day-'). In the mid-slopes, in particular along a central depression, saturation of the shallow soils caused macropore channel recharge to take place through the clay-textured subsoils. Water-level responses suggest that approximately 25-30 per cent of annual recharge occurred from one storm studied in September 1984. Recharge through macropore channels is a significant mechanism in the concave slope areas on the hillslope. Throughflow was found to be a major source of water, but not salt, contributing to the saline seep. In general, the contribution of throughflow was found to decrease further inland at other sites studied. However, at inland sites where perennial, perched aquifers have developed in deep sands, saline areas have been caused by throughflow and not by deep aquifer discharge.

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Section: Groundwater Balance Estimatesmentioning

confidence: 99%

Interactions between perched and saprolite aquifers on a small, salt‐affected and deeply weathered hillslope

George¹,

Conacher

1993

Earth Surf Processes Landf

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“…The early models were mostly empirical and statistical, and were aimed at estimating the changes in water yield and salinity on an annual basis. Examples include the models developed by Peck (1976), Loh and Stokes (1981) and Schofield (1988). Macpherson and Peck (1987) developed a statistical model to predict the daily flows and stream salinities on a cleared catchment by correlating recorded data in this catchment with that from an adjacent control catchment that was left uncleared.…”

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confidence: 98%

Water and salt balance modelling to predict the effects of land‐use changes in forested catchments. 1. Small catchment water balance model

Sivapalan

Ruprecht

Viney

1996

Hydrological Processes

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A long-term water balance model has been developed to predict the hydrological effects of land-use change (especially forest clearing) in small experimental catchments in the south-west of Western Australia. This small catchment model has been used as the building block for the development of a large catchment-scale model, and has also formed the basis for a coupled water and salt balance model, developed to predict the changes in stream salinity resulting from land-use and climate change. The application of the coupled salt and water balance model to predict stream salinities in two small experimental catchments, and the application of the large catchment-scale model to predict changes in water yield in a medium-sized catchment that is being mined for bauxite, are presented in Parts 2 and 3, respectively, of this series of papers.The small catchment model has been designed as a simple, robust, conceptually based model of the basic daily water balance fluxes in forested catchments. The responses of the catchment to rainfall and pan evaporation are conceptualized in terms of three interdependent subsurface stores A, B and F. Store A depicts a near-stream perched aquifer system; B represents a deeper, permanent groundwater system; and F is an intermediate, unsaturated infiltration store. The responses of these stores are characterized by a set of constitutive relations which involves a number of conceptual parameters. These parameters are estimated by calibration by comparing observed and predicted runoff. The model has performed very well in simulations carried out on Salmon and Wights, two small experimental catchments in the Collie River basin in south-west Western Australia. The results from the application of the model to these small catchments are presented in this paper.

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“…During the low-flow period of the year, when mainly the baseflow component was active, the modelled and observed daily salinity was not well matched, particularly during the period when surface salt was flushed out by storm events. The salt accumulation and flushing from the stream zone are attributed to: (a) the magnitude and location of clearing, (b) groundwater table during the previous summer and capillary rise, and (c) summer streamflow and magnitude of early winter flows (Loh and Stokes, 1981). That means the accumulation of salts on the surface due to soil evaporation, and its dilution and flushing by the surface runoff, is not well simulated by the model.…”

Section: Discussionmentioning

confidence: 96%

A daily salt balance model for stream salinity generation processes following partial clearing from forest to pasture

Bari

Smettem

2006

Hydrol. Earth Syst. Sci.

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Abstract. We developed a coupled salt and water balance model to represent the stream salinity generation process following land use changes. The conceptual model consists of three main components with five stores: (i) Dry, Wet and Subsurface Stores, (ii) a saturated Groundwater Store and (iii) a transient Stream zone Store. The Dry and Wet Stores represent the salt and water movement in the unsaturated zone and also the near-stream dynamic saturated areas, responsible for the generation of salt flux associated with surface runoff and interflow. The unsaturated Subsurface Store represents the salt bulge and the salt fluxes. The Groundwater Store comes into play when the groundwater level is at or above the stream invert and quantifies the salt fluxes to the Stream zone Store. In the stream zone module, we consider a "free mixing" between the salt brought about by surface runoff, interflow and groundwater flow. Salt accumulation on the surface due to evaporation and its flushing by initial winter flow is also incorporated in the Stream zone Store. The salt balance model was calibrated sequentially following successful application of the water balance model. Initial salt stores were estimated from measured salt profile data. We incorporated two lumped parameters to represent the complex chemical processes like diffusion-dilutiondispersion and salt fluxes due to preferential flow. The model has performed very well in simulating stream salinity generation processes observed at Ernies and Lemon experimental catchments in south west of Western Australia. The simulated and observed stream salinity and salt loads compare Correspondence to: M. A. Bari (mohammed.bari@environment.wa.gov.au) very well throughout the study period with NSE of 0.7 and 0.4 for Ernies and Lemon catchment respectively. The model slightly over predicted annual stream salt load by 6.2% and 6.8%.

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Predicting stream salinity changes in South-Western Australia

Cited by 19 publications

References 4 publications

Interactions between perched and saprolite aquifers on a small, salt‐affected and deeply weathered hillslope

Interactions between perched and saprolite aquifers on a small, salt‐affected and deeply weathered hillslope

Water and salt balance modelling to predict the effects of land‐use changes in forested catchments. 1. Small catchment water balance model

A daily salt balance model for stream salinity generation processes following partial clearing from forest to pasture

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