The challenge of water conservation and water demand management for irrigated agriculture in South Africa

Pott, Andrew; Hallowes, Jason; Backeberg, Gerhard R.; Döckel, Max

doi:10.1080/02508060903114657

Cited by 8 publications

(3 citation statements)

References 1 publication

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“…This correspondingly leads to an increase in the water resource demand. Unfortunately, approximately 98% of the predicted total surface water resources are already used up such that the demand already exceeds the surface water supply in half of the nine WMAs (Pott et al 2009; Le Maitre et al 2019). To circumvent the prevailing water stress situation, the South African National Water Resource Strategy considers groundwater resources as an important consideration for the future planning and management of freshwater resources (Hedden and Cilliers 2014).…”

Section: Introductionmentioning

confidence: 99%

Catchment‐Wide Groundwater Budget for the Inkomati‐Usuthu Water Management Area in South Africa

Shakhane,

Mojabake

2024

Groundwater

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In South Africa, approximately 98% of the predicted total surface water resources are already being used up. Consequently, the National Water Resource Strategy considers groundwater to be important for the future planning and management of water resources. In this case, quantifying groundwater budgets is a prerequisite because they provide a means for evaluating the availability and sustainability of a water supply. This study estimated the regional groundwater budgets for the Inkomati‐Usuthu Water Management Area (Usuthu, Komati, Sabie‐Sand, and Crocodile) using the classical hydrological continuity equation. The equation was used to describe prevailing feedback loops between groundwater draft, recharge, baseflow, and storage change. The results were coarser scale estimates which, beforehand, were derived from the 2006 study. In the years to follow, groundwater reliance intensified and there was also the historic 2015/2016 drought. This inevitably led to an increased draft while the rest of the components of the groundwater budgets experienced decreases. Both Crocodile and Sabie‐Sand experienced groundwater storage depletion which led to reduced baseflow and groundwater availability, while groundwater recharge contrarily increased due to capture. Conversely, the other two catchments experienced relatively lower drafts with correspondingly higher groundwater availability and recharge while storage change was positive. The results highlighted the need for adaptive water management whose effectiveness relies on predictive studies. Consequently, future models should be developed to capture the spatial and temporal dynamism of the natural groundwater budget due to climate change, water demands, and population growth predictions.

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Section: Introductionmentioning

confidence: 99%

Catchment‐Wide Groundwater Budget for the Inkomati‐Usuthu Water Management Area in South Africa

Shakhane,

Mojabake

2024

Groundwater

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“…The days when the sole purpose of irrigation was to increase crop production are now in the distant past. Farmers are under increasing pressure, specifically to prevent the degradation of water resources, and also to produce higher yields with less water (Hillel and Vlek, 2005;Pott et al, 2009;Kijne, 2011). Advocates for a more sustainable irrigation sector attempt to empower farmers and encourage them to continually evaluate and improve on-farm water and salt management (Kijne, 2006).…”

Section: Introductionmentioning

confidence: 99%

Water and salt balances of two shallow groundwater cropping systems using subjective and objective irrigation scheduling

Barnard

Rensburg

Bennie

et al. 2017

WSA

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Evidence suggests that, in general, subjective rather than objective irrigation scheduling decisions are adopted by farmers. Irrigators have 'calibrated' themselves with years of experience to irrigate subjectively according to perceived crop water requirements. This study aimed to determine the associated benefits of objective versus subjective scheduling of two shallow groundwater cropping systems. Weekly measurements included rainfall and irrigation amounts, soil water content, groundwater table depth, artificial drainage volumes, and electrical conductivity of irrigation water, groundwater and drainage water. Simulations of evaporation and transpiration were done with the SWAMP model. Based on soil water and salinity status, matric and osmotic stress during the four cropping seasons is considered unlikely. When rainfall-plusirrigation was compared to evapotranspiration, objective scheduling resulted in an under-supply of 15%, and rainfall and shallow groundwater served as supplementary water sources. Subjective scheduling did not use rainfall efficiently as a source of water and resulted in an over-supply of 10%. Approximately 50% less salt was leached with objective compared to subjective irrigation scheduling. Under shallow groundwater conditions, irrigating subjectively according to crop water requirement results in excessive irrigation, salt addition and leaching compared to objective scheduling. Farmers can address some of the environmental problems associated with irrigation by adopting objective scheduling and reducing the leaching fraction (< 0.15) of shallow groundwater cropping systems.

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“…As a result, demand for water far exceeds the capacity of several catchments to provide. Over 50% of South Africa's catchments are considered to be over-allocated (Pott et al, 2009) as surface water resources become fully developed. In the context of rural development, rural communities use water for a wide range of productive and domestic uses, all of which are important to their livelihoods.…”

Section: Introductionmentioning

confidence: 99%

Sand water storage: Unconventional methods to freshwater augmentation in isolated rural communities of South Africa

Otieno¹,

Olufayo

Ochieng³

2011

Sci. Res. Essays

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South Africa water resources are scarce in global terms with mean annual rainfall of about half world average of 860 mm a year. On the other hand, current economy development with resulting contamination of available water resources will further reduce water availability, if present patterns of water use continue unchanged. The conventional water resources (largely surface water) in the country have been fully exploited with little opportunity for further expansion. So therefore, new approaches are necessary by accessing alluvial aquifers of non-perennial rivers in forming additional water resources in this part of semi-arid region. High evaporative losses from surface storage, increasing costs of large dams and aridity conditions have hindered development of conventional water resources with increasing interest in using groundwater for rural water supply. Many South Africa rivers are nonperennial, therefore, development of unconventional sand water storage is appealing for freshwater augmentation in isolated rural communities. This paper presents overviews of South Africa water resources highlighting sand water storage options for potential application in rural water supply for isolated communities where groundwater potential is low.

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The challenge of water conservation and water demand management for irrigated agriculture in South Africa

Cited by 8 publications

References 1 publication

Catchment‐Wide Groundwater Budget for the Inkomati‐Usuthu Water Management Area in South Africa

Catchment‐Wide Groundwater Budget for the Inkomati‐Usuthu Water Management Area in South Africa

Water and salt balances of two shallow groundwater cropping systems using subjective and objective irrigation scheduling

Sand water storage: Unconventional methods to freshwater augmentation in isolated rural communities of South Africa

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