**7. Resource management implications**

A more appropriate and adequate dataset is essential for the planning and management of aquifers. Monitoring is, therefore, closely linked to the aquifer management, since the results of monitoring may require changes or modifications in the management practice. For example, the higher than average rainfall in the 2010/2011 season across Victoria (all reflected in the hydrograph analysis) may have influence on water use decisions and water restrictions. However, sustainable groundwater management decisions would require long-term monitoring and projections. Such long-term data covering all key elements of the hydrological cycle including groundwater fluctuations and water-level trends are essential as a basis for management and for evaluating the implications of changes in use.

Long-term monitoring using a number of observation bores has demonstrated that water levels have both declined and recovered over time and in the aquifer investigated. There has been full recovery of the aquifer over the past wet months (2010-2011), and this has been much more than what the recovery would have been over a normal wet year in Victoria. However, this is no cover against management measures except such higher than average rainfall becomes consistent over a longer period of time. Such monitoring data will be 'handy' information to support decision-making and demonstrate the impacts of climate on level changes in relation to resource management. Water level and quality data has been used a number of times in Victoria and (at least three occasions within the last 7 years) in Cape Town to change the extent of groundwater abstraction in order to support sustainable management.

Changes in Groundwater Level Dynamics in Aquifer Systems –

be used for stock and domestic purposes.

water strategies.

its feedback.

Implications for Resource Management in a Semi-Arid Climate 91

In 1998, new groundwater management arrangements were put in place to maximise development opportunities in the Werribee Irrigation District, yet ensure that groundwater resources are managed in a sustainable way. Management arrangements include Groundwater Management Areas (GMAs); Groundwater Supply Protection Areas (GSPAs); and Groundwater Management Plans (SRWA, 2006). Water restrictions have since been in place and at different stages of restriction, they are periodically reviewed. For example, in March 2011, Southern Rural Water announced a substantial boost in groundwater allocation for landowners in the Deutgam Water Supply Protection Area based around Werribee. A full ban on groundwater use in Werribee was introduced in 2006 because of the threat of seawater intrusion into the groundwater through aquifer from Port Phillip Bay (SRWA, 2006). SRWA announced a partial lifting to 25% allocation in early January 2011, and recommended to the Minister a lifting to 75% after careful monitoring showed the aquifer is continuing to improve (SRWA, 2011). More than average mean rainfall over the last 12 months has seen groundwater levels rising and salinity levels improving. All bores can now

Currently the Department of Water Affairs (Cape Town regional office) is capacityconstrained, which limits its ability to continue groundwater monitoring and the processing of licence applications (Colvin & Saayman, 2007). In such a situation, very little additional management of groundwater resources is possible. However, by the year 2012, DWA aims to complete institutional transformation with the establishment of Water User Associations (WUAs) and Catchment Management Agencies; and the licensing of all water use within another 5 years. Also, the City of Cape Town adopted an integrated approach to water management, which seeks a balance between water conservation and water demand management initiatives and conventional supply augmentation. But based on observations (Colvin & Saayman, 2007), formal government tend to focus on bulk water supply while household level bore use and development planning has not been fully integrated into

Private (household) use of groundwater from the Cape Flats aquifer is widespread and increasing since the early 2000s when potable water tariffs increased. The immediate impact of such unregulated use was not feasible in this study due to prolonged missing gaps (mid-1990s to early 2000s) in water level data. The current gradual downward trend if projected would reflect in future bore responses as monitoring continues. To support this, the survey conducted by Colvin and Saayman (2007) revealed society's impacts on groundwater currently result from indirect drivers such as Water Demand Measure (WDM) introduced in the mid-1990s. This obviously occurs within the broader context of society supported by natural resources and a model which includes the resource base and

Although the Department is aware of the increased private groundwater abstraction at a household level in Cape Town, this water use is covered under Schedule 1 of the National Water Act and therefore does not need to be registered with the Department. The cumulative impact of these small-scale abstractions generates concerns. Colvin and Saayman (2007) suggested that where the cumulative effect of these small-scale abstractions under Schedule 1 is too large and negative, by-laws or regulations can be promulgated even by a municipality. Such a by-law or regulation would override the entitlements under

Fig. 6. Areal distribution map of electrical conductivity (in μS/cm) in the Cape Flats (Adelana et al., 2010)

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Fig. 6. Areal distribution map of electrical conductivity (in μS/cm) in the Cape Flats

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In 1998, new groundwater management arrangements were put in place to maximise development opportunities in the Werribee Irrigation District, yet ensure that groundwater resources are managed in a sustainable way. Management arrangements include Groundwater Management Areas (GMAs); Groundwater Supply Protection Areas (GSPAs); and Groundwater Management Plans (SRWA, 2006). Water restrictions have since been in place and at different stages of restriction, they are periodically reviewed. For example, in March 2011, Southern Rural Water announced a substantial boost in groundwater allocation for landowners in the Deutgam Water Supply Protection Area based around Werribee. A full ban on groundwater use in Werribee was introduced in 2006 because of the threat of seawater intrusion into the groundwater through aquifer from Port Phillip Bay (SRWA, 2006). SRWA announced a partial lifting to 25% allocation in early January 2011, and recommended to the Minister a lifting to 75% after careful monitoring showed the aquifer is continuing to improve (SRWA, 2011). More than average mean rainfall over the last 12 months has seen groundwater levels rising and salinity levels improving. All bores can now be used for stock and domestic purposes.

Currently the Department of Water Affairs (Cape Town regional office) is capacityconstrained, which limits its ability to continue groundwater monitoring and the processing of licence applications (Colvin & Saayman, 2007). In such a situation, very little additional management of groundwater resources is possible. However, by the year 2012, DWA aims to complete institutional transformation with the establishment of Water User Associations (WUAs) and Catchment Management Agencies; and the licensing of all water use within another 5 years. Also, the City of Cape Town adopted an integrated approach to water management, which seeks a balance between water conservation and water demand management initiatives and conventional supply augmentation. But based on observations (Colvin & Saayman, 2007), formal government tend to focus on bulk water supply while household level bore use and development planning has not been fully integrated into water strategies.

Private (household) use of groundwater from the Cape Flats aquifer is widespread and increasing since the early 2000s when potable water tariffs increased. The immediate impact of such unregulated use was not feasible in this study due to prolonged missing gaps (mid-1990s to early 2000s) in water level data. The current gradual downward trend if projected would reflect in future bore responses as monitoring continues. To support this, the survey conducted by Colvin and Saayman (2007) revealed society's impacts on groundwater currently result from indirect drivers such as Water Demand Measure (WDM) introduced in the mid-1990s. This obviously occurs within the broader context of society supported by natural resources and a model which includes the resource base and its feedback.

Although the Department is aware of the increased private groundwater abstraction at a household level in Cape Town, this water use is covered under Schedule 1 of the National Water Act and therefore does not need to be registered with the Department. The cumulative impact of these small-scale abstractions generates concerns. Colvin and Saayman (2007) suggested that where the cumulative effect of these small-scale abstractions under Schedule 1 is too large and negative, by-laws or regulations can be promulgated even by a municipality. Such a by-law or regulation would override the entitlements under

Changes in Groundwater Level Dynamics in Aquifer Systems –

seawater intrusion (studies to confirm this are on-going).

areas.

frameworks for semi-arid regions.

in comparison to the Werribee Delta aquifer bores (-3 to 4 cm/yr).

Implications for Resource Management in a Semi-Arid Climate 93

number hydrograph of bores in the area. The bore hydrographs of the Cape Flats aquifer showed marked seasonal fluctuations and a more slightly downward trend (-8 to 14 cm/yr)

The resulting groundwater declines invariably affect groundwater resource sustainability and by implication water security. For example, the Werribee Delta aquifer groundwater level drawdown shows that during the early 1990s seasonal drawdown was less than 0.5 m but increased up to 2 m in 1996. The decline and general downward trend indicates increased reliance on groundwater. The fall in groundwater levels coincides with salinity increases from 2,500 EC to over 6,000 EC and, consequently yielding information that the source of salinity in the Werribee Delta could be more than saline adjacent aquifers or

Groundwater level responses and behaviour in observation bores, in response to climate and pumping in productive aquifers, is an indication of homogeneity and lateral hydraulic connection within the shallow coastal aquifers investigated in this study. However, the cases involving deeper aquifers and their responses were not considered. This is because the shallow aquifers are mostly used in both study area and the hydrogeological parameters have shown higher yield of these aquifers relative to the deeper ones. It is expected that vertical hydraulic conductivity will vary with the various underlying geological materials and only if aquifer connectivity exist that pumping from one productive aquifer can induce water level change in observation bores installed in other aquifers. Therefore, a more comprehensive study investigating the impacts of level changes in shallow aquifers on underlying deeper aquifer(s) would be necessary for effective resource management in these

The groundwater trends and salinity increases are discussed in the context of groundwater resource sustainability and its implications on water security and resource management plans, including consideration of water conservation measures or conjunctive water use. However, aspects relating changes in groundwater level and zones of declining groundwater head to aquifer connectivity may be necessary to improve understanding of the system and, by implication, critical to the development of sustainable management

In the face of the prolonged dry period (1995-2007) and a come-back of wet years (2010/2011), current irrigation and agricultural practices need to be reviewed in the catchments to ensure groundwater sustainability and secure future agricultural viability. Groundwater level responses in bores (consistent level records in WID, coupled with the data gaps in the Cape Flats farming districts), illustrate the importance of monitoring in relation to natural/environmental responsiveness and resilience. State-wide groundwater monitoring in Victoria (Australia) and the quarterly meter reading has continued to assist management decisions. There are realities surrounding groundwater use and inherent risks associated with development, the level of uncertainty and the range of social pressures. The social views of groundwater lag behind the formal policy of a public resource. Therefore, continued support for basic data collection and groundwater evaluation is justified on both scientific and social process grounds. The water authorities in the two case studies must adequately manage and maintain interactions with key stakeholders ensuring open and

transparent relationships that are based on trust to promote good governance.

Schedule 1. As far as information available to date, no such by-laws or regulations have been promulgated either by DWA or the City of Cape Town.

Colvin and Saayman's (2007) survey further reveal there are concerns within government Departments (Department of Water Affairs and the Department of Agriculture) that the national land reform programme may be contributing to unsustainable resource exploitation in places. For example, some of the Cape Flats bores in Atlantis area (shown in the appendix) represent a marked response to pumping influences with a decline of 4-6 m within 1-2 years in mid-1990s and then continuous decline into the early 2000s. Such high declines may influence spring flows and base flows, and hence, have implications on groundwater resource management. Some of these monitoring bores are responding to pumping influences from the Atlantis wellfields. Bulk water supply wellelds at Atlantis have been in operation for over 20 years, supplying the satellite industrial town with water (Tredoux, 1982; Tredoux & Cave, 2002). This led to the establishment of a management scheme, known as the Atlantis Water Resource Management Scheme (AWRMS) to manage water resources in the area and to follow on the introduction of WDM in the South African Water Act 1997. The City of Cape Town also commissioned the Council for Scientific and Industrial Research (CSIR) to conduct intensive monitoring and numerical modelling of the Atlantis wellelds (Colvin & Saayman, 2007). Such information would help management of the groundwater resource.

Generally groundwater acts as the primary buffer against the impact of climate variability and spatial variability in drought. The buffering capacity of groundwater increases social resilience to drought in both urban and rural communities. However, as human development has become more susceptible to such variability, three major gaps in groundwater management were identified (FAO, 2003b): accelerated degradation of groundwater systems by over-abstraction, and effective resource depletion through quality changes (pollution, salinity), and the inability to resolve competition for groundwater between sectoral and environmental uses. Each of these has implications for sustainable development as demonstrated in this study.

Given the sensitivity of both aquifers to climate variability and pumping and the observed water quality changes noted above, it is considered necessary to uphold formal regulatory measures to avert further water level and quality decline. Effective institutional approaches need to be aware of the realities surrounding groundwater use and the inherent risks associated with development, the level of uncertainty (plus limitations in data quality) and the range of social pressures. The general lack of professional and public awareness about the sustainable use of groundwater resources will need to be continuously addressed. A more coherent planning framework should guide all scales of groundwater development and appropriate policy responses needed to prevent further degradation of the groundwater systems.
