Ramsis Salama

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Catchment Hydrogeological Characterisation and Evaluation: An Hierarchical Approach

A methodology has been developed directly from an understanding of geomorphology, hydrogeology an... more A methodology has been developed directly from an understanding of geomorphology, hydrogeology and the understanding of the effects of these systems on groundwater and solute movement in the landscape. The methodology takes into account the role of geology in controlling weathering patterns, and the influence of topography in forming geomorphic and hydrogeomorphic units. It also combines geology and geomorphology in controlling surface runoff, infiltration, recharge and discharge. The parameterisation and characterisation techniques are classified into three levels; broadscale, analytical and accurate. Comparing the three methods for hydrogeological characterisation and evaluation of a catchment showed that there are small differences when estimating areas of recharge and discharge and predicting water levels. There is a difference of 10-30% between the methods when estimating discharge. The results show that the broadscale method offers a very quick way of examining and evaluating ...

Impacts of Vegetation Change on the Water Balance of Superficial, Coastal Aquifers: a Comparative Study of Pre-clearing and Post-clearing Recharge Under Native Vegetation, and Pine Plantations

ABSTRACT Replacing native vegetation with pasture across the northern Perth Basin in Western Aust... more ABSTRACT Replacing native vegetation with pasture across the northern Perth Basin in Western Australia has profoundly altered the water balance and led to dramatic increases in recharge and groundwater levels from about the mid-1960&#39;s, whereas replacing native vegetation with pine plantations and market gardens further south in the Gnangara groundwater Mound together with declining rainfall has caused continuous declines in recharge and water levels. Long-term monitoring of water levels in the Parmelia Formation, a superficial, semi-confined aquifer of predominantly weathered sand in the northern Perth Basin, indicates maximum rates of water level rise on the order of 40 to 55 cm/yr within the past decade. In the Gnangara Mound, water levels are falling by 10 to 20 cm/yr in the unconfined aquifer. Quantifying groundwater capture due to the removal of native vegetation is crucial for predicting the extent of groundwater development in the northern Perth Basin, whereas in the Gnangara Mound, it is necessary to limit the total water use to the declining resource to arrest the trend in falling water levels. Estimates of groundwater recharge before the removal of native vegetation in the northern Perth Basin determined from chloride tracer measurements in the soil water beneath native bushland and from groundwater samples ranged from 12 to 16 mm/yr, while estimates from soil water flux at the water table are approximately 5 mm/yr. In contrast, recharge estimates under cleared conditions since 1970 are between 24 and 50 mm/yr, based on hydrograph analyses of different bores. CFC and chloride analyses of water sampled from piezometers screened at the water table gave recharge estimates of 20 to 30 mm/yr and less than 10 mm/yr, respectively. In the Gnangara Mound recharge varies between 70 to 200 mm/year; the lowest recharge values were under the pines and the highest in the urban areas. Due to increasing demand on the groundwater resources and the declining water levels, additional resources can be provided only by removing the pine plantations, proper management of the Banksia woodland areas and capture of fresh groundwater discharging to the sea.

Will Greening the Brown Land Reverse Salinity Trends and Save Country Towns from Drowning

The management of excess recharge has been accepted as a key factor in restoration of the long-te... more The management of excess recharge has been accepted as a key factor in restoration of the long-term hydrological balance in salinised agricultural catchments. The link is examined between hydrogeomorphological characteristics and the biological and engineering components available to manage recharge and discharge. Specific interest is in the use of the characteristics to determine sites for tree plantations of adequate size to transpire the required volume of excess recharge. Application of the methodology is shown in 3 catchment case studies. An engineering plan to save the town of Brockton may need to be accepted because of socio-economic factors.

Linked Enhanced Discharge - Evaporation Disposal Systems for the Control of Dryland Salinity

The performance of a linked - evaporative disposal system was monitored for one year in the wheat... more The performance of a linked - evaporative disposal system was monitored for one year in the wheatbelt of Western Australia. Saline groundwater was pumped (115 m3d{-1}) from the overpressured basement aquifer which is hydraulically connected to the unconfined system. Leakage rates exceed evaporation rates by orders of magnitude. Aquifer leakage from the basin is mainly captured and recycled by the pumping well. The salinity of the water in the basin increased significantly during the summer months, but an increase groundwater salinity was not observed. The design and site selection of a linked disposal system can be optimised (i.e. minimising leakage, maximising evaporation) by applying the linear relationship between hydraulic head difference and aquifer leakage. On-farm evaporation basins which are hydraulically linked to an enhanced discharge scheme are a practical solution to the disposal problem of saline effluent (TDS >5000 mgl{-1}) generated by pumping to control land and s...

Can Pumping Reduce Water Levels and Reverse Salinity Trends in Palaeochannels

Broad valleys in Western Australia are mainly associated with the relict drainage, or the palaeoc... more Broad valleys in Western Australia are mainly associated with the relict drainage, or the palaeochannel system. These palaeochannels are characterised by the presence of coarse sediments varying in thickness from 10 m at the flanks to 50 m in the central parts of the channel. The alluvial sandy sediments form a series of horizontally permeable layers which are interconnected through vertically permeable layers. In most cases these layers are separated by clay layers which increase in thickness towards the banks. The sediments are saturated with brines which vary in concentration from 40,000 mg/L to 100,000 mg/L. Aquifer transmissivity ranges from 10 m(2)d(-1) near the banks to 50 m(2)d(-1) in the deepest part of the channel with an average hydraulic conductivity of 5 m(2)d(-1). Long term water level monitoring showed that palaeochannel aquifers are in direct hydraulic connection with the surface runoff receiving annual recharge from through the stream beds. Long term pumping for 12 ...

Can Pumping Reduce Water Levels and Reverse Salinity Trends in Palaeochannels?

Linked Enhanced Discharge - Evaporation Disposal Systems for the Control of Dryland Salinity

Evolution study of a regional groundwater system using hydrochemistry and stable isotopes in Songnen Plain, northeast China

Hydrological Processes, 2007

Groundwater is often a critical source of water for municipal, industrial and agricultural uses, ... more Groundwater is often a critical source of water for municipal, industrial and agricultural uses, especially in arid and semi-arid environments. Songnen Plain, located in the central part of northeast China, is such a region, it being an important productive base of commodity grain in this country. In the past two decades, groundwater quality in the region, especially salinization, has deteriorated under natural changes and human activities, and has become a crucial factor restricting sustainable ecoenvironmental and socio-economic development. In this paper, The Taoer River catchment, situated in the middle of the region, was selected as the study area for the groundwater quality evolution study using hydrochemistry and stable isotopes to obtain a better understanding of the system. Fifty-two groundwater samples were collected with systematic design during the low-water and high-water periods in 2003. A series of comprehensive quality data interpretations, e.g. statistics, ratios of ions and Piper diagrams, together with stable isotope data, have been used to gain an insight into the spatial and temporal variations and evolution laws of groundwater hydrochemistry. The following main hydrochemical processes were identified as controlling the water quality of the groundwater system: weathering-dissolution, evaporation-condensation, ion-exchange reactions and groundwater salinization. This latter process, salinization, is the most important process and is caused by the leaching of superficial or near-surface salts from the saline-alkaline soil into shallow groundwater.

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Catchment Hydrogeological Characterisation and Evaluation: An Hierarchical Approach

The Renaissance Dam in Ethiopia

The evolution of the River Nile. The buried saline rift lakes in Sudan—I. Bahr El Arab Rift, the Sudd buried saline lake

Journal of African Earth Sciences (1983), 1987

... LAKES The evolution of the chemical composition of saline lake waters consists of two steps: ... more

The Evolution of Saline Lakes in the Relict Drainage of the Yilgarn River, Western Australia

Sedimentology and Geochemistry of Modern and Ancient Saline Lakes, 1994

Page 1. THE EVOLUTION OF SALINE LAKES IN THE RELICT DRAINAGE OF THE YILGARN RIVER WESTERN AUSTRAL... more

Remote Sensing of Soils and Plants Imagery

Encyclopedia of Earth Sciences Series, 2011

Applications of reflective remote sensing for land degradation studies in a mediterranean environment

Geomorphology, 1995

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Controls on the Salinisation of the Collie Catchment, Southwestern Australia

The Collie River drainage basin is an important water resource catchment in southwestern Australi... more The Collie River drainage basin is an important water resource catchment in southwestern Australia. Salinisation of the major water supply, the Wellington Dam, has arisen due to changes in the water and salt balance in response to land clearing. Results from a recent study in several paired catchments provides further insight into the scale of processes influencing water and salt

Review of “Groundwater modeling in semiarid Central Sudan: adequacy and long-term abstraction” (Abdalla 2009a)

Arabian Journal of Geosciences, 2009

ABSTRACT

Impacts of Vegetation Change on the Water Balance of Superficial, Coastal Aquifers: a Comparative Study of Pre-clearing and Post-clearing Recharge Under Native Vegetation, and Pine Plantations

by E. Bekele and Ramsis Salama

Agu Fall Meeting Abstracts, Dec 1, 2003

Replacing native vegetation with pasture across the northern Perth Basin in Western Australia has... more Replacing native vegetation with pasture across the northern Perth Basin in Western Australia has profoundly altered the water balance and led to dramatic increases in recharge and groundwater levels from about the mid-1960's, whereas replacing native vegetation with pine plantations and market gardens further south in the Gnangara groundwater Mound together with declining rainfall has caused continuous declines in recharge and water levels. Long-term monitoring of water levels in the Parmelia Formation, a superficial, semi-confined aquifer of predominantly weathered sand in the northern Perth Basin, indicates maximum rates of water level rise on the order of 40 to 55 cm/yr within the past decade. In the Gnangara Mound, water levels are falling by 10 to 20 cm/yr in the unconfined aquifer. Quantifying groundwater capture due to the removal of native vegetation is crucial for predicting the extent of groundwater development in the northern Perth Basin, whereas in the Gnangara Mound, it is necessary to limit the total water use to the declining resource to arrest the trend in falling water levels. Estimates of groundwater recharge before the removal of native vegetation in the northern Perth Basin determined from chloride tracer measurements in the soil water beneath native bushland and from groundwater samples ranged from 12 to 16 mm/yr, while estimates from soil water flux at the water table are approximately 5 mm/yr. In contrast, recharge estimates under cleared conditions since 1970 are between 24 and 50 mm/yr, based on hydrograph analyses of different bores. CFC and chloride analyses of water sampled from piezometers screened at the water table gave recharge estimates of 20 to 30 mm/yr and less than 10 mm/yr, respectively. In the Gnangara Mound recharge varies between 70 to 200 mm/year; the lowest recharge values were under the pines and the highest in the urban areas. Due to increasing demand on the groundwater resources and the declining water levels, additional resources can be provided only by removing the pine plantations, proper management of the Banksia woodland areas and capture of fresh groundwater discharging to the sea.

Groundwater quality in the Ord irrigation area, its suitability for irrigation and prediction of salinity and sodicity hazards

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C S I R O L A N D a nd W AT E R Geochemical Interactions between Groundwater and Soil, Groundwater Recycling and Evaporation in the ORIA

To the extent permitted by law, CSIRO Land and Water (including its employees and consultants) ex... more To the extent permitted by law, CSIRO Land and Water (including its employees and consultants) excludes all liability to any person for any consequences, including but not limited to all losses, damages, costs, expenses and any other compensation, arising directly or indirectly from using this publication (in part or in whole) and any information or material contained in it.

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Mapping zones of higher groundwater and solute movement using airborne geophysics in a heterogeneous aquifer ? A case study in weathered crystalline basement rocks, southwestern Australia

ASEG Extended Abstracts, 2003

... weathered crystalline basement rocks, southwestern Australia Jasmine Rutherford* Ramsis Salam... more

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