The term 'safe yield', or its buzzword adaptation 'sustainable yield', is lately being used by many groundwater specialists when they are discussing Sustainable Groundwater Management issues. Some specialists use these terms
of 9
All materials on our website are shared by users. If you have any questions about copyright issues, please report us to resolve them. We are always happy to assist you.
Related Documents
   1 BEYOND THE BUZZWORDS – WHAT DOES “SUSTAINABLE GROUNDWATER MANAGEMENT” REALLY MEAN? Bosman, Carin Carin Bosman Sustainable Solutions P O Box 26442 GEZINA, 0031 Tel 082 803 2384 Fax 086 693 5189 E-mail : cbosman@global.co.za  ABSTRACT The term ‘safe yield’, or its buzzword adaptation ‘sustainable yield’, is lately being used by many groundwater specialists when they are discussing Sustainable Groundwater Management issues. Some specialists use these terms interchangeably, while others (Alley and Leake, 2004) state that the concept of ‘safe yield’ is closely aligned with the concept of ‘sustainability’. However, instances where ‘safe yield’ were advocated for more than 20 years as being the fundamental objective to achieve Sustainable Groundwater Management, such as in Arizona, are currently being re-evaluated, as it seems that it is a more elusive goal than once predicted. When discussing “Sustainable Groundwater Management”, it is of utmost importance to properly distinguish between the concepts ‘safe yield’, ‘sustainable yield’ and ‘sustainability’. This is necessary to avoid situations where decisions regarding groundwater management are made based on concepts such as ‘safe yield’, but due to a misunderstanding to the meaning of ‘safe yield’ in the context of ‘sustainable environmental management’ the decision does not lead to ‘sustainability’, but to degradation , over exploitation and even mining of aquifers. Where ‘safe yield’ is in essence a scientific term, ‘sustainability’ is a socio-political concept, and these concepts are most certainly not related, and neither ‘safe yield’ nor ‘sustainable yield’ is the forerunner for ‘sustainability’. Confusing these terms with each other can hence lead to serious problems when trying to establish what ‘Sustainable Groundwater Management’ entails, especially in efforts to ensure ‘Sustainable Groundwater Management’ in a developing world context. This paper briefly differentiates between the concepts of ‘safe yield’, ‘sustainability’, and ‘sustainable yield’, and discusses these terms in the context of some of the principles of ‘sustainable environmental management’ (as outlined in section 2 of the National Environmental Management Act, 107 of 1998). In particular, the relationship between the concept of ‘safe yield’ and ‘assimilative’ or ‘carrying capacity’ as principle for Sustainable Environmental Management is discussed. In conclusion, some guidance to determine what “Sustainable Groundwater Management” would entail for specific situations, in the context of these principles, as well as the guidelines of the World Water Forum for ‘Integrated Water Resource Management’, is provided. KEYWORDS sustainability, sustainable yield, safe yield, assimilative capacity, carrying capacity, sustainable groundwater management, environmental management.   2   INTRODUCTION In 1987, in the Report of the World Commission on Environment and Development (WCED), which is now referred to as the Brundtland Report, sustainable development was defined as: “ development that meets the needs of the present without compromising the ability of future generations to meet their own needs ” (Gardner, 1989 and others). Sustainability is hence in essence a socio-political concept.  Natural scientists are trained to study and measure aspects of the natural environment. Therefore, when groundwater specialists were faced with the concept of ‘sustainability’ or ‘sustainable development’, attempts were made to adapt this concept to the science of groundwater resources. Some (Alley et al 1999, Alley 2004, and others) stated that the application of sustainability to groundwater resources require that the effects of many different human activities on water resources should be understood and quantified  to the best extent possible. Groundwater scientists naturally attempted to relate the concept of sustainability to something known to them, and Alley (2004) stated that sustainability is closely aligned with the known concept of safe yield. In the field of groundwater management, ‘safe yield’ is the term used to express the amount of water an aquifer or well can yield for consumption over time, beyond which the groundwater resource risks the state of over-exploitation or even depletion, and has been in use since 1915. Due to this alignment, some specialists (Shrivastava, 2003 and Zhang and Kennedy, 2006) even started using the term ‘sustainable yield’ to describe ‘the ecological yield that can be used without reducing the base of resource itself.’ As a result of this scientific ‘adaptation’ of the socio-political concept of sustainability, a risk of miscommunication and misunderstanding arises that could potentially lead to great confusion when attempting to develop options for Sustainable Groundwater Management. This paper attempts to clarify some of these misconceptions by firstly examining the concepts of yield and sustainability. On the basis of this, some deductions are drawn with regard to the applicability of the use of terms such as ‘safe yield’ and even ‘sustainable yield’ when discussing Sustainable Groundwater Management. Lastly, some guiding principles for sustainable groundwater management are discussed in the context of the principles of sustainable environmental management and integrated water resources management, and conclusions and recommendations regarding these aspects are made. YIELD When discussing “Sustainable Groundwater Management”, it is of utmost importance to properly distinguish between the concepts ‘safe yield’, ‘sustainable yield’ and ‘sustainability’. This is necessary to avoid situations where decisions regarding groundwater management are made based on concepts such as ‘safe yield’, but the decision does not lead to ‘sustainability’, but to over-exploitation and degradation of aquifers. ‘Safe Yield’ In the field of groundwater management, ‘safe yield’ is the term used to express the amount of water an aquifer or well can yield for consumption, beyond which the groundwater resource risks the state of over-exploitation or even depletion. Safe yield of water extraction is measurable and quantified in volume extracted per unit time. Todd (1959, in Alley, 2004) defined safe yield of a groundwater basin as: “the amount of water that can be annually drawn from it without producing an undesired result”. A common misconception (Alley, 2004) is that the development of a groundwater basin is ‘safe’ if the annual average rate of withdrawal does not exceed the average   3 annual rate of recharge. This leads to problems, as temporal withdrawal rates are not taken into account. The definition of safe yield was initially developed based on a simplistic view of how a ground water basin might be developed to maximise the quantity of water that can be withdrawn, and although the concept expanded over time to include legal, economic and water quality considerations, some problems are still being experienced. These problems are perhaps being experienced because of including these non-scientific factors into a scientific calculation, as illustrated by the following example: In many parts of Africa, the only factor taken into consideration when managing aquifers as a water resource is the ‘safe yield’ of well-fields or boreholes. In Ethiopia (Lulu and Hiwot, 2004) ‘safe yield’ is determined by a relatively simple linear equation where capacity at stabilised drawdown is multiplied by available head and a safety factor. There is no standard set for this safety factor, and it is left to the  judgement of the designer of the well-field or the borehole. Sometimes, aspects such as climatic conditions, water quality and perhaps even geology, would be considered, but more often than not, the safety factor used is quite high, usually in the order of 80%, even in cases where incrustation is expected, due to the fact that ‘economic need’ is given a high rating. Lulu et al (2004) quite emphatically show that although the safe yield equation is linear, which assumes that drawdown is  proportional to discharge, this is most definitely not the case in especially fractured aquifers.  Nevertheless, the use of non-scientific ‘judgements’ disguises the srcinal intention of the determination of safe yield, namely to quantify the desirable development of a ground water basin. In another example, the scientific concept of ‘safe yield’, has been used to achieve political objectives. The fundamental objective of Arizona’s 1980 Groundwater Management Act was stated ‘to achieve safe yield’ as their Sustainable Groundwater Management solution. The Act  prescribed that this was to be achieved by all means possible, including in some instances using urban waste water for artificial recharge. The feature article in the October 1998 edition of the Arizona Water Resource (AWA, 1998) states that some of the assumptions and projections used to set this goal have not held up after 20 years, which result that ‘safe yield’ may be a difficult target to achieve using the current mechanisms. ‘Sustainable Yield’ The term ‘sustainable yield’, especially when used in relation to renewable natural resources, is the ecological yield that can be used without reducing the base of resource itself, i.e. the levels required to maintain nature's services at the same or increasing level over time. This yield usually varies over time with the needs of the ecosystem to maintain itself, e.g. a surface water resource that has recently suffered a drought or a severe pollution incident will require more of its own ecological capacity to sustain and re-establish itself to its equilibrium. While doing so, the sustainable yield may be much less than before the drought or pollution incident. It may be very difficult to quantify sustainable yield, because every dynamic ecological conditions and other factors not related to harvesting induce changes and fluctuations in both, the natural capital and its productivity. According to Fuggle and Rabie (1994:51), one of the great environmental and economic tasks facing South African policy-makers is to identify levels of maximum sustainable yield for renewable resources. The reason for this is perhaps that there are various conceptual problems with the term ‘sustainable yield’ in itself, as the concept of sustainability goes beyond yield, but includes quality, and other aspects, as outlined below. ‘SUSTAINABILITY’ The 1987 WCED Report stated that the concept of “sustainability” should not be confused with that of “sustainable development”. To distinguish between these terms, one should consider the concept of equity, which is both temporal and intergenerational. Temporal equity is the present   4 fairness of policies and actions, and refers to the equity between, for example, race and gender. Intergenerational equity,  or equality between generations, is the ultimate moral principle behind the notion of sustainability , since its goal is the maintenance of natural resources for future generations (Geisler, 1981 in Rickson & Rickson, 1990). Sustainability  is the long term and difficult aim of reaching a sustainable ecological state of equilibrium, whereas the variable and as yet poorly-defined process  by which this goal is to be achieved is called sustainable development  (Dovers and Handmer, 1993). The terms “sustainable development” and “sustainable use” are used interchangeably, although “development” more often refers to a new action or the expansion of an existing activity, whereas “use” refers to all actions, existing or proposed, that have or may have an impact on resources. When a natural resource is utilised in such a manner that the functioning of its systems is not compromised, but rather maintained in such a manner that future generations can share the same quality of life as the present generation, this is referred to as “ sustainable use ”. (Bosman, 1999) The 1987 WCED Report furthermore stated that sustainable development is in essence "  a process  of change in which the exploitation of resources, the direction of investment, the re-orientation of technology development, and institutional change are all in harmony and enhance both  current  and future potential to meet human needs and aspirations ".  The needs of the present generation is relatively clear, and can be summarised as economic needs (eg adequate livelihood, financial security, etc) social, cultural and health needs (eg shelter, water, food, education, etc) and political needs (eg freedom in decisions about the future, quality of life, etc). The needs of the future generation cannot as easily be described, and more importantly, the present generation cannot  be the judge on whether or not an action or activity is actually sustainable– only the next generation can make that judgement. This implies that ‘sustainability’ cannot be quantified, at least not by the  present generation. Since ‘sustainability’ is a long term and difficult aim of reaching a sustainable ecological state of equilibrium that cannot be quantified, a set of principles for Sustainable Environmental Management was developed and adopted worldwide in an attempt to address the needs of the future generation and to guide decision-making towards achieving this goal. PRINCIPLES OF SUSTAINABLE ENVIRONMENTAL MANAGEMENT In this context, the term environment  is used in its broadest form, and includes biophysical, social, economic, historical, cultural and political aspects. Environmental management should not be confused with the management (manipulation) of the natural environment (e.g. nature conservation, the management or even manipulation of plants and animals, etc). Gilpin (1996:170) states that: “  Environmental management is a  concept of care  applied to individual premises, corporate enterprises, localities, regions, catchments, natural resources, areas of high conservation value, lifetime cycles, waste handling and disposal, cleaner processing and recycling systems, with the  purpose of protecting the environment in the broadest sense. It involves the identification of objectives, the adoption of appropriate mitigation measures, the protection of ecosystems and natural resources, the enhancement of quality of life for those affected, and the minimisation of environmental costs”.  Guiding this management approach is a set of key principles, which srcinated from several initiatives, such as Caring for the Earth , the Rio Declaration and Agenda 21. In South Africa, these environmental management principles are incorporated into section 2 of the National Environmental Management Act 107 of 1998, to serve as the general framework within which environmental management and implementation plans must be formulated and as r  eference to which any organ of state must exercise any function when taking any decision in terms of both  NEMA or any other Act or statutory provision concerning the protection of the environment. Some of these principles are summarised in Table 1 below:   5   Table 1: Some Principles of Sustainable Environmental Management Principle Description The Precautionary  approach This is a pro-active principle aimed at avoiding environmental impact  before it occurs, and has the purpose of preventing pollution. The Rio Declaration states that environmental protection is an integral part of the development process, and cannot be considered in isolation. The Polluter Pays   principle This principle maintains that the polluter should bear the full cost of any damage caused to the environment, and entails the internalisation of external costs. This implies that resource economics should be employed to ensure that the market price of a commodity should reflect environmental costs, threats, risks and liabilities. The Cradle to Grave   principle This principle implies that there is “No away”, and that the impacts of actions should be managed throughout project, product and/or service life cycles, from reconnaissance and conception to rehabilitation and aftercare. The principle of an I ntegrated and Holistic approach The extended definition of “environment” is supported by this  principle and entails an integration of traditional scientific realms and a holistic approach to the management of potential impacts on the environment. The principle that due consideration must be given to all alternative options . The most sustainable option, known as the Best Practical Environmental Option (BPEO) should be implemented. The BPEO is defined by the British Royal Commission on Environmental Pollution as “the outcome of a systematic consultative and decision-making procedure that emphasises the protection of the environment across land, air and water. It establishes, for a given set of objectives, the option that provides the most benefit or least damage to the environment as a whole at a cost acceptable to society in the short as well as long term” (Hawkins, 1996). The BPEO is the option that will  balance long term economic, environmental and social concerns. The Carrying Capacity   principle This principle is aimed at ensuring the responsible use of natural resources, so that development does not exceed the natural carrying capacity of environmental systems, and forms the basis of the selection of the BPEO. It is discussed in more detail below. Continual Improvement  The continual improvement principle implies that as our knowledge of environmental systems improves, we should improve the mechanisms  by means of which we manage. This means that decision-making should be based on the best available scientific knowledge. Accountability and Liability  This principle implies firstly that line function managers are criminally liable for actions causing pollution or damage to the environment. It implies secondly that there must be accountability for information  provided and for decisions that may have an effect on the environment, and, thirdly that a clear cut-off point must be set to define pollution or degradation. Transparency and Democracy  This principle suggests that the people whose environment will be affected by a decision or action should be given the opportunity to be involved in such a decision, and that the manner in which decisions are taken should be transparent and reasonable. Environmental management is based on these principles, is aimed at achieving the goal of sustainability. Due to the potentially conflicting nature of different needs and aspirations, the Deming approach of Total Quality Management (TQM) is used for Environmental Management. This implies a “Plan, Do, Check, Act” approach aimed at continual improvement and customer satisfaction, where the natural environment is regarded as the key customer.
Related Search
We Need Your Support
Thank you for visiting our website and your interest in our free products and services. We are nonprofit website to share and download documents. To the running of this website, we need your help to support us.

Thanks to everyone for your continued support.

No, Thanks

We need your sign to support Project to invent "SMART AND CONTROLLABLE REFLECTIVE BALLOONS" to cover the Sun and Save Our Earth.

More details...

Sign Now!

We are very appreciated for your Prompt Action!