A desktop model used to provide an initial estimate of the ecological instream flow requirements of rivers in South Africa

Hughes, Denis A.; Hannart, Pauline

doi:10.1016/s0022-1694(02)00290-1

Cited by 148 publications

(104 citation statements)

References 7 publications

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“…Nevertheless, the principle is believed to be sound and LIFE has the major advantage of utilising the data collected by existing bio-monitoring programmes so is compatible with the European Water Framework Directive. Hughes and Munster (2000) and Hughes and Hannart (2003) developed a desktop method to provide initial estimates of environmental flow needs for rivers in South Africa. The user calculates a hydrological index (i.e.…”

Section: Desk Top Analysismentioning

confidence: 99%

Defining environmental river flow requirements – a review

Acreman

Dunbar

2004

Hydrol. Earth Syst. Sci.

504

375

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Around the world, there is an increasing desire, supported by national and regional policies and legislation, to conserve or restore the ecological health and functioning of rivers and their associated wetlands for human use and biodiversity. To achieve this, many organisations have developed methods for defining environmental flows, i.e. the flow regime required in a river to achieve desired ecological objectives. This paper reviews the various methods available and suggests a simple categorisation of the methods into four types: look-up tables, desktop analysis; functional analysis and hydraulic habitat modelling. No method is necessarily better than another; each may be suitable for different applications. Whilst look-up methods are easy and cheap to apply, they can be expensive to develop, are less accurate and more suitable for scoping studies; in contrast, although hydraulic habitat modelling is more expensive to apply, it is suitable for impact assessment at specific sites. Each method would need to be used within a wider decision-support framework. These are generally either objective-based to define a target flow regime for a specific desired river status, or scenario-based to indicate the relative merits of various flow regime options for the river environment.

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Section: Desk Top Analysismentioning

confidence: 99%

Defining environmental river flow requirements – a review

Acreman

Dunbar

2004

Hydrol. Earth Syst. Sci.

504

375

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“…Iran's agricultural strategy identifies water productivity improvement as a top priority. Supplemental irrigation has been recommended as an important practice for increasing crop and water productivity in these rainfed areas of the upper KRB, which comprise important suitable rainfed zones of Iran (Keshavarz and Sadeghzadeh, 2000;Tavakoli et al, 2008Tavakoli et al, , 2010.…”

Section: Introductionmentioning

confidence: 99%

“…Methods for estimating environmental flow requirements (EFRs) include hydrological methods, hydraulic rating, habitat simulation, and holistic methods (Mazvimavi et al, 2007). More than 30 criteria for single-river EFRs have been developed and used worldwide (Tennant, 1976;Hughes and Hannart, 2003;Mazvimavi et al, 2007;Ramsar Convention Secretariat, 2007;Smakhtin, 2001;Smakhtin et al, 2006). However, a lack of hydroecological studies often limits the choice of an EFR method.…”

Section: Introductionmentioning

confidence: 99%

Supplemental irrigation potential and impact on downstream flow of Karkheh River basin in Iran

Hessari¹,

Bruggeman²,

Akhoond‐Ali³

et al. 2016

Hydrol. Earth Syst. Sci.

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Abstract. Supplemental irrigation of rainfed winter crops improves and stabilises crop yield and water productivity. Although yield increases by supplemental irrigation are well established at the field level, its potential extent and impact on water resources at the basin level are less researched. This work presents a Geographic Information Systems (GIS)-based methodology for identifying areas that are potentially suitable for supplemental irrigation and a computer routine for allocating streamflow for supplemental irrigation in different sub-basins. A case study is presented for the 42 908 km 2 upper Karkheh River basin (KRB) in Iran, which has 15 840 km 2 of rainfed crop areas. Rainfed crop areas within 1 km from the streams, with slope classes 0-5, 0-8, 0-12, and 0-20 %, were assumed to be suitable for supplemental irrigation. Four streamflow conditions (normal, normal with environmental flow requirements, drought and drought with environmental flow) were considered for the allocation of water resources. Thirty-seven percent (5801 km 2 ) of the rainfed croplands had slopes less than 5 %; 61 % (3559 km 2 ) of this land was suitable for supplemental irrigation, but only 22 % (1278 km 2 ) could be served with irrigation in both autumn (75 mm) and spring (100 mm), under normal flow conditions. If irrigation would be allocated to all suitable land with slopes up to 20 %, 2057 km 2 could be irrigated. This would reduce the average annual outflow of the upper KRB by 9 %. If environmental flow requirements are considered, a maximum (0-20 % slopes) of 1444 km 2 could receive supplemental irrigation. Under drought conditions a maximum of 1013 km 2 could be irrigated, while the outflow would again be reduced by 9 %. Thus, the withdrawal of streamflow for supplemental irrigation has relatively little effect on the outflow of the upper KRB. However, if the main policy goal would be to improve rainfed areas throughout the upper KRB, options for storing surface water need to be developed.

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“…In Brazil, the minimum flow to be maintained below a major dam should be at least 80% of the minimum average monthly flow (Benetti et al, 2002). Hughes & Hannart (2003) developed a desktop method to provide approximate estimates of environmental flow needs for rivers in South Africa. They defined a hydrological index (i.e.…”

Section: Comparison With Standards For Other Countriesmentioning

confidence: 99%

Developing environmental standards for abstractions from UK rivers to implement the EU Water Framework Directive / Développement de standards environnementaux sur les prélèvements d'eau en rivière au Royaume Uni pour la mise en œuvre de la directive cadre sur l'eau de l'Union Européenne

Acreman

Dunbar

Hannaford

et al. 2008

Hydrological Sciences Journal

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Under the European Union Water Framework Directive, Member States must put in place a river basin planning framework to determine what measures are necessary to maintain and improve the ecological status for all surface water bodies. The governmental organisations legally responsible for implementing the Directive in the UK have recognised that an appropriate river flow regime is fundamental to maintain a healthy river and, as a result, they need to regulate abstractions and effluent discharges and ensure sufficient water is released from impoundments. This paper reports on the process of producing environmental standards that define the maximum abstraction allowable from UK rivers, to leave sufficient flow to maintain a healthy river ecosystem. As there are currently insufficient data available to determine the relationships between river flow and ecological status empirically, expert knowledge was captured through a series of workshops at which leading UK freshwater scientists defined maximum levels of river flow regime alteration that would achieve ecological objectives for different river water body types. For the least ecologically sensitive rivers, maximum abstractions in the range 15-35% of the natural flow were proposed, depending on the flow magnitude and time of year. For the most sensitive rivers, the maximum abstraction proposed was in the range 7.5-25%. The knowledge was used by the responsible UK authorities to develop environmental standards. The authorities subsequently used the environmental standards to determine regulatory standards that could be implemented within practical constraints and current licensing policies.Key words Water Framework Directive; environmental standards; abstraction management; rivers; expert panel; environmental flows; ecohydrology; hydro-ecology Développement de standards environnementaux sur les prélèvements d'eau en rivière au Royaume Uni pour la mise en oeuvre de la directive cadre sur l'eau de l'Union Européenne Résumé La directive cadre sur l'eau de l'Union Européenne impose aux Etats membres de mettre en place un cadre de gestion des bassins versants afin de déterminer les mesures nécessaires au maintien et à l'amélioration de l'état écologique des eaux de surface. Les organismes gouvernementaux légalement responsables de la mise en oeuvre de la directive au Royaume Uni ont reconnu qu'un régime hydrologique approprié est fondamental pour la bonne santé d'une rivière et que, en conséquence, ils doivent réglementer les prélèvements et les rejets et assurer un débit suffisant en sortie des retenues. Cet article porte sur le processus de production de standards environnementaux définissant les prélèvements maximaux possibles dans les rivières britanniques en vue du maintien de la bonne santé des écosystèmes de cours d'eau. Etant donnée l'insuffisance des données disponibles pour déterminer empiriquement une relation entre débit de rivière et état écologique, la connaissance experte a été capturée à travers une série d'ateliers lors desquels les principaux s...

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A desktop model used to provide an initial estimate of the ecological instream flow requirements of rivers in South Africa

Cited by 148 publications

References 7 publications

Defining environmental river flow requirements – a review

Defining environmental river flow requirements – a review

Supplemental irrigation potential and impact on downstream flow of Karkheh River basin in Iran

Developing environmental standards for abstractions from UK rivers to implement the EU Water Framework Directive / Développement de standards environnementaux sur les prélèvements d'eau en rivière au Royaume Uni pour la mise en œuvre de la directive cadre sur l'eau de l'Union Européenne

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