Journal ArticleDOI
Environmental effects of flow regulation on the lower river Murray, Australia
Keith F. Walker,Martin Thoms +1 more
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In the lower Murray basin, the regime changed with the construction of 10 low-level weirs in 1922-35, supplemented by the effects of dams in upstream areas as mentioned in this paper.Abstract:
Before regulation flows in the lower Murray were highly variable, as for most rivers in semi-arid regions. Major floods promoted large-scale recruitment of flora and fauna in riverine and floodplain communities, and seasonal floods maintained lower levels of recruitment. The regime changed with the construction of 10 low-level weirs in 1922-35, supplemented by the effects of dams in upstream areas. Flows remain variable but are much reduced in volume (about 44%). Low flows (100-300 GI per month) have decreased five-fold and moderate flows (500-1500 GI per month) have increased two-fold. Although the magnitude of peak seasonal flows has been diminished, the timing of flows is unaffected. The effects differ in the Valley and Gorge sections of the river, depending on local development of the floodplain and associated wetlands. The weirs have flooded once-temporary wetlands and contributed to problems of salinization. Weir operations cause daily stage fluctuations that diminish downstream, and the channel is developing a stepped gradient as a consequence of active deposition and erosion. Regulation has limited exchanges between the river and its floodplain, changed the nature of the littoral zone and generally created an environment inimical to many native species, notably fish. The key to rehabilitation may be to restore a more natural balance of low and medium flows, but this may be unrealistic. given the needs of irrigators and other water users. Despite its evolutionary history of wide spatial and temporal variation, the Murray river-floodplain ecosystem evidently cannot accommodate these forms of disturbance.read more
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How much water does a river need
TL;DR: In this paper, the authors proposed a new approach for setting streamflow-based river ecosystem management targets and this method is called the "Range of Variability Approach" (RVA), which derives from aquatic ecology theory concerning the critical role of hydrological variability, and associated characteristics of timing, frequency, duration and rates of change, in sustaining aquatic ecosystems.
Journal ArticleDOI
Low flow hydrology: a review
TL;DR: Low-flow hydrology is a discipline which deals with minimum flow in a river during the dry periods of the year as mentioned in this paper, and it has been extensively studied in the literature.
Journal ArticleDOI
Ecological impacts of dams, water diversions and river management on floodplain wetlands in Australia
TL;DR: In Australia, the Murray-Darling Basin is most affected with dams which can store 103% of annual runoff and 87% of divertible water extracted (1983-84 data) as discussed by the authors.
Journal ArticleDOI
A global perspective on wetland salinization: ecological consequences of a growing threat to freshwater wetlands
Ellen R. Herbert,Paul I. Boon,Amy J. Burgin,Scott C. Neubauer,Rima B. Franklin,Marcelo Ardón,Kristine N. Hopfensperger,Leon P. M. Lamers,Peter Gell +8 more
TL;DR: Salinization, a widespread threat to the structure and ecological functioning of inland and coastal wetlands, is currently occurring at an unprecedented rate and geographic scale as discussed by the authors, and the causes of salinization are diverse and include alterations to freshwater flows, land-clearance, irrigation, disposal of wastewater effluent, sea level rise, storm surges, and applications of de-icing salts.
Journal ArticleDOI
A perspective on dryland river ecosystems
TL;DR: In this paper, the authors re-appraised the ecosystem concept for dryland rivers, with regard for flow as an organizing variable, and modelled river processes by combining the river continuum and flood pulse concepts, with refinements to accommodate a complex flood pulse.
References
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