Hydrogeomorphic Effects of Reservoirs, Dams, and Diversions

Petts, Geoffrey E.; Gurnell, Angela M.

doi:10.1016/b978-0-12-818234-5.00034-1

Cited by 9 publications

(5 citation statements)

References 182 publications

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“…Over recent centuries, human impacts on European river landscapes have greatly intensified. Engineering interventions such as channel realignment and deepening (Brookes, 1988), floodplain ‘reclamation’ or drainage, and dam construction (Petts & Gurnell, 2021) have resulted in widespread and severe degradation of river ecosystems (Petts et al, 1989). Historical analysis has shown how New Forest wetlands and streams have been affected by engineering activities, especially channel realignment and deepening, and the installation of drain systems to improve grazing and support forestry.…”

Section: Discussionmentioning

confidence: 99%

River channel changes through time and across space: Using three commonly available information sources to support river understanding and management in a national park

Gurnell

Hill

2021

Earth Surf Processes Landf

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In river landscapes subject to prolonged and high population pressure, the impact of human actions is usually so pervasive that re-establishment of 'natural' river conditions is not possible. However, understanding the impacts of humans on river ecosystems is essential to identify how degradation of condition may be slowed or reversed and may also lead to the recognition that some human activities may be crucial for maintaining highly valued and sensitive river ecosystems. To achieve the necessary understanding for such judgements, it is essential to assemble, synthesize and analyse information on human actions, river environments and their interactions. In this paper, we focus on three commonly available information sources (historical records/ archives, topographic and geomorphological maps, river habitat surveys) that can deliver relevant information over three timescales (centuries, decades, years). We illustrate the potential of these three data sources to assemble thematic and quantitative knowledge about how river systems function under a history of different human pressures and interventions, by exploring an example river landscape: the New Forest, southern England. We use this illustrative example for three reasons.First, for more than 1000 years, the New Forest has been affected by a complex range of land use and management practices which have heavily influenced the contemporary river landscape. Second, many of these human actions have degraded the landscape but others sustain highly valued landscape characteristics and ecosystems.Understanding the relative negative and positive impacts of different human actions is essential to understanding any river landscape with a long history of human use, and thus to designing balanced and appropriate management approaches. Third, in this special issue in memory of Professor Ken Gregory, we focus on an example landscape where he conducted research, allowing us to incorporate insights and data from his observations.geomorphological mapping, historical sources, human impacts, river habitat survey, river monitoring design, river processes, time and space scales | INTRODUCTIONRiver landscapes within Europe, as in many other areas of the world, have long been modified by both direct and indirect human actions. The resultant impacts are most deep-seated in areas of prolonged, high population density. In such areas it is not possible to restore rivers to a pre-impact, 'natural' condition, but it may be possible to slow or reverse degradation and to improve river functioning and condition (Brierley & Fryirs, 2008;Dufour & Piégay, 2009). The term 'restoration' can still be applied in its widest sense to refer to all activities that assist the recovery of river ecosystems that have been degraded, damaged or destroyed

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Section: Discussionmentioning

confidence: 99%

River channel changes through time and across space: Using three commonly available information sources to support river understanding and management in a national park

Gurnell

Hill

2021

Earth Surf Processes Landf

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“…Environmental flow shortages can be partially addressed by measures to enhance riverine geomorphic processes (Petts & Gurnell 2013; Yarnell et al 2015; Palmer & Ruhi 2019), perhaps utilizing flow‐deflecting objects such as large woody debris (Bond & Lake 2005; Howson et al 2009; Howson et al 2012; Dunkerley 2014) or other revetment structures (Kinzli & Myrick 2009) that can enhance habitat complexity at smaller spatial scales. Such geomorphic processes can create scour pools that alter surface water/groundwater connections and river base flows, which often represent a large component of total river discharge (Miller et al 2016; Rumsey et al 2020).…”

Section: Discussionmentioning

confidence: 99%

Mitigation of recurrent perturbation mortality is an important goal for river restoration and conservation of freshwater fish species

Hatch

Abadi

Porter

et al. 2022

Restoration Ecology

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Human perturbations affect many aquatic ecosystems globally. We use age-structured matrix population models to explore how population growth rates in short-lived freshwater fish are affected by recurrent environmental perturbations to river ecosystems. Simulations are summarized to reveal how species-specific fitness characteristics contribute to population sustainability in habitats subject to recurrent perturbation. Deterministic calculations are used to estimate time to population recovery with successive years of intermittence disturbance, followed by post-perturbation equilibrium conditions. Perturbation that reduces only juvenile survival has a shorter recovery time to initial population size and greater resilience of population growth than when adult survival is reduced. Consecutive occurrences of perturbation lengthen recovery time nonlinearly, more notably when adults experience perturbation mortality. We illustrate with an example how managers could identify multiple options to mitigate recurrent ecosystem perturbations by reducing perturbation frequency and/or mitigating perturbation mortality. Our simulations suggest parameter approximations for a hypothetical species provide a useful frame of reference for river restoration and conservation when life history data are lacking for a specific species of concern.

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“…Modification of river courses, particularly by construction of dams, reduce connectivity between erosion areas in basins and channels (Nilsson et al, 2005;Magilligan et al, 2013;Petts and Gurnell, 2013;Liu et al, 2017;Beylich and Laute, 2021) and, consequently, solid load transported by rivers to the oceans may diminish (Vörösmarty et al, 2003;Syvitski et al, 2005a;Walling, 2006;Syvitski and Kettner, 2011;Walling, 2012;Scorpio and Piégay, 2021). For instance, Vörösmarty et al (2003) found that 53% of sediment load in regulated rivers in different parts of the world was trapped in dams, and Yang et al (2015) concluded that the reduction of sediment load observed in the Yangtze River in the periods 1950-1968 and 2003-2012 was due to reservoirs (approx.…”

Section: Sediment Fluxesmentioning

confidence: 99%