1000 resultados para Streamflow regulation


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Streamflow is considered a driver of inter and intra‐specific life‐history differences among freshwater fish. Therefore, dams and related flow regulation, can have deleterious impacts on their life‐cycles. The main objective of this study is to assess the effects of flow regulation on the growth and reproduction of a non‐migratory fish species. During one year, samples were collected from two populations of Iberian chub, inhabiting rivers with non‐regulated and regulated flow regimes. Flow regulation for water derivation promoted changes in chub’s condition, duration of gonad maturation and spawning, fecundity and oocyte size. However, this non‐migratory species was less responsive to streamflow regulation than a migratory species analysed. Findings from this study are important to understand changes imposed by regulated rivers on fish and can be used as guidelines for flow requirements implementations; RESUMO: O caudal é um dos fatores responsáveis pelo funcionamento dos ciclos de vida das espécies piscícolas dulciaquícolas. As barragens, e a regularização de caudal associada, podem ter impactes nos ciclos de vida destas espécies. O objetivo deste estudo prende‐se com a avaliação dos efeitos da regularização de caudal no crescimento e reprodução de uma espécie piscícola não‐migradora. A análise de amostras recolhidas em populações de escalo do Norte provenientes de dois rios de caudal regularizado e não regularizado, identificaram impactes significativos a nível da condição corporal, da maturação das gónadas e desova, da fecundidade e da dimensão dos oócitos. Esta espécie não‐migradora parece ser menos responsiva à artificialização do caudal que uma espécie migradora previamente analisada. Estes resultados permitem compreender as alterações impostas pela regularização do caudal e podem ser usados em programas de reabilitação fluvial.

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The hydrological response of a catchment to rainfall on different timescales is result of a complex system involving a range of physical processes which may operate simultaneously and have different spatial and temporal influences. This paper presents the analysis of streamflow response of a small humid-temperate catchment (Aixola, 4.8 km(2)) in the Basque Country on different timescales and discusses the role of the controlling factors. Firstly, daily time series analysis was used to establish a hypothesis on the general functioning of the catchment through the relationship between precipitation and discharge on an annual and multiannual scale (2003-2008). Second, rainfall-runoff relationships and relationships among several hydrological variables, including catchment antecedent conditions, were explored at the event scale (222 events) to check and improve the hypothesis. Finally, the evolution of electrical conductivity (EC) during some of the monitored storm events (28 events) was examined to identify the time origin of waters. Quick response of the catchment to almost all the rainfall events as well as a considerable regulation capacity was deduced from the correlation and spectral analyses. These results agree with runoff event scale data analysis; however, the event analysis revealed the non-linearity of the system, as antecedent conditions play a significant role in this catchment. Further, analysis at the event scale made possible to clarify factors controlling (precipitation, precipitation intensity and initial discharge) the different aspects of the runoff response (runoff coefficient and discharge increase) for this catchment. Finally, the evolution of EC of the waters enabled the time origin (event or pre-event waters) of the quickflow to be established; specifically, the conductivity showed that pre-event waters usually represent a high percentage of the total discharge during runoff peaks. The importance of soil waters in the catchment is being studied more deeply.

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A novel approach is proposed to estimate the natural streamflow regime of a river and to assess the extent of the alterations induced by dam operation related to anthropogenic (e.g., agricultural, hydropower) water uses in engineered river basins. The method consists in the comparison between the seasonal probability density function (pdf) of observed streamflows and the purportedly natural streamflow pdf obtained by a recently proposed and validated probabilistic model. The model employs a minimum of landscape and climate parameters and unequivocally separates the effects of anthropogenic regulations from those produced by hydroclimatic fluctuations. The approach is applied to evaluate the extent of the alterations of intra-annual streamflow variability in a highly engineered alpine catchment of north-eastern Italy, the Piave river. Streamflows observed downstream of the regulation devices in the Piave catchment are found to exhibit smaller means/modes, larger coefficients of variation, and more pronounced peaks than the flows that would be observed in the absence of anthropogenic regulation, suggesting that the anthropogenic disturbance leads to remarkable reductions of river flows, with an increase of the streamflow variability and of the frequency of preferential states far from the mean. Some structural limitations of management approaches based on minimum streamflow requirements (widely used to guide water policies) as opposed to criteria based on whole distributions are also discussed. Copyright © 2010 by the American Geophysical Union.

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This issue of the Griffith Law Review focuses on consumer law, and the pervasive nature of this area of law. We are all consumers, but do not necessarily identify as such, nor are we a homogeneous group. The boundaries of

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Australia is currently well placed to contribute to the global growth of human stem cell research. However, as the science has progressed, authorities have had to deal with the ongoing challenges of regulating such a fast moving field of scientific endeavour. Australia’s past and current approach to regulating the use of embryos in human embryonic stem cell research provides an insight into how Australia may continue to adapt to future regulatory challenges presented by human stem cell research. In the broader context, a number of issues have been identified that may impact upon the success of future human stem cell research in Australia.

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Human embryonic stem cell research promises to deliver in the future a whole range of therapeutic treatments, but currently governments in different jurisdictions must try to regulate this burgeoning area. Part of the problem has been, and continues to be, polarised community opinion on the use of human embryonic stem cells for research. This article compares the approaches of the Australian, United Kingdom and United States governments in regulating human embryonic stem cell research. To date, these governments have approached the issue through implementing legislation or policy to control research. Similarly, the three jurisdictions have viewed the patentability of human embryonic stem cell technologies in their own ways with different policies being adopted by the three patent offices. This article examines these different approaches and discusses the inevitable concerns that have been raised due to the lack of a universal approach in relation to the regulation of research; the patenting of stem cell technologies; and the effects patents granted are having on further human embryonic stem cell research.

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The commercialisation of therapeutic products containing regenerative human tissue is regulated by the common law, statute and ethical guidelines in Australia and England, Wales and Northern Ireland. This article examines the regulatory regimes in these jurisdictions and considers whether reform is required to both support scientific research and ensure conformity with modern social views on medical research and the use of human tissue. The authors consider the crucial role of informed consent in striking the balance between the interests of researchers and the interests of the public.

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The need to “reduce red tape” and regulatory inconsistencies is a desirable outcome (OECD 1997) for developed countries. The costs normally associated with regulatory regimes are compliance costs and direct charges. Geiger and Hoffman (1998) have noted that the extent of regulation in an industry tends to be negatively associated with firm performance. Typically, approaches to estimation of the cost of regulations examine direct costs, such as fees and charges, together with indirect costs, such as compliance costs. However, in a fragmented system, such as Australia, costs can also be incurred due to procedural delays, either by government, or by industry having to adapt documentation for different spheres of government; lack of predictable outcomes, with variations occurring between spheres of government and sometimes within the same government agency; and lost business opportunities, with delays and red tape preventing realisation of business opportunities (OECD 1997). In this submission these costs are termed adaptation costs. The adaptation costs of complying with variations in regulations between the states has been estimated by the Building Product Innovation Council (2003) as being up to $600 million per annum for building product manufacturers alone. Productivity gains from increased harmonisation of the regulatory system have been estimated in the hundreds of millions of dollars (ABCB 2003). This argument is supported by international research which found that increasing the harmonisation of legislation in a federal system of government reduces what we have termed adaptation costs (OECD 2001). Research reports into the construction industry in Australia have likewise argued that improved consistency in the regulatory environment could lead to improvements in innovation (PriceWaterhouseCoopers 2002), and that research into this area should be given high priority (Hampson & Brandon 2004). The opinion of industry in Australia has consistently held that the current regulatory environment inhibits innovation (Manley 2004). As a first step in advancing improvements to the current situation, a summary of the current costs experienced by industry needs to be articulated. This executive summary seeks to outline these costs in the hope that the Productivity Commission would be able to identify the best tools to quantify the actual costs to industry.