Modelling of environmental flow options for optimal Atlantic salmon, Salmo salar, embryo survival during hydropeaking

Recent findings on the causes of Atlantic salmon embryo mortality during winter in a hydropeaking river suggest that long duration drawdowns during very cold periods are the most likely cause of mortality in the ramping zone. This paper presents a framework in which thresholds for optimal embryo survival at the microscale are linked to physical habitat requirements at the mesoscale and integrated into alternative hydropower operations at the catchment scale. The connections within this framework are derived from a one-dimensional hydraulic model at the mesoscale and a hydropower simulation programme at the catchment scale. The economic costs and feasibility of several alternative options for hydropeaking operation that would comply with ecological requirements for optimal survival of embryos were evaluated. A method to assess a wide range of alternative hydropower options that considers key factors to mitigate the conflicting requirements of ecological targets, technical feasibility and economics is presented. Targeted alternative environmental flow releases to meet specific ecological objectives are often more effective than general operational rules to comply with legislation. The development of well-informed and targeted mitigation strategies is important for future environmental hydropower management.

[1]  Lake District Stream.  NUMERICAL CHANGES AND POPULATION REGULATION IN YOUNG MIGRATORY TROUT SALMO TRUTTA IN A , 2016 .

[2]  K. Alfredsen,et al.  The Survival of Atlantic Salmon (Salmo salar) Eggs During Dewatering in a River Subjected to Hydropeaking , 2015 .

[3]  K. Alfredsen,et al.  Performance of a One‐Dimensional Hydraulic Model for the Calculation of Stranding Areas in Hydropeaking Rivers , 2015 .

[4]  K. Alfredsen,et al.  Optimising Atlantic salmon smolt survival by use of hydropower simulation modelling in a regulated river , 2014 .

[5]  S. Saltveit,et al.  Incubation, hatching and survival of eggs of Atlantic salmon (Salmo salar) in spawning redds influenced by groundwater ☆ , 2013 .

[6]  C. Gibbins,et al.  The influence of hydrology and hydraulics on salmonids between spawning and emergence: implications for the management of flows in regulated rivers , 2012 .

[7]  S. Schmidt,et al.  What is groundwater and what does this mean to fauna? – An opinion , 2012 .

[8]  Maria Catrinu,et al.  Perspectives on hydropower’s role to balance non-regulated renewable power production in Northern EuropeReport on the CEDREN workshop, Düsseldorf, 15-16 December 2010 , 2011 .

[9]  C. Gibbins,et al.  Hydrological Influences on Adult Salmonid Migration, Spawning, and Embryo Survival , 2008 .

[10]  G. Pasternack,et al.  Relationships between mesoscale morphological units, stream hydraulics and Chinook salmon (Oncorhynchus tshawytscha) spawning habitat on the Lower Yuba River, California , 2008 .

[11]  Piotr Parasiewicz,et al.  The MesoHABSIM model revisited , 2007 .

[12]  Jon P. Sadler,et al.  Linking hydrology and biology to assess the water needs of river ecosystems , 2006 .

[13]  C. Rakowski,et al.  Estimated Fall Chinook Salmon Survival to Emergence in Dewatered Redds in a Shallow Side Channel of the Columbia River , 2005 .

[14]  P. Borsányi.  A classification method for scaling river biotopes for assessing hydropower regulation impacts , 2005 .

[15]  E. Beall,et al.  Nest Placement and Egg Distribution in Atlantic Salmon Redds , 2004, Environmental Biology of Fishes.

[16]  C. Soulsby,et al.  Survival of salmonid eggs in a degraded gravel‐bed stream: effects of groundwater–surface water interactions , 2003 .

[17]  Jan Juretzka,et al.  Decision Support System , 2001 .

[18]  M. Newson,et al.  Geomorphology, ecology and river channel habitat: mesoscale approaches to basin-scale challenges , 2000 .

[19]  C. Gibbins,et al.  Salmonid habitat modelling studies and their contribution to the development of an ecologically acceptable release policy for kielder reservoir, North-East England. , 2000 .

[20]  Ian Maddock,et al.  The Importance of Physical Habitat Assessment for Evaluating River Health , 1999 .

[21]  David M. Harper,et al.  Use of ‘functional habitats’ to link ecology with morphology and hydrology in river rehabilitation , 1999 .

[22]  R. Cunjak,et al.  Inter‐stage survival of wild juvenile Atlantic salmon, Salmo salar L. , 1998 .

[23]  Alpha Microprocessor,et al.  Performance of an , 1998 .

[24]  C. L. Padmore.  The role of physical biotopes in determining the conservation status and flow requirements of British rivers , 1998 .

[25]  Terry D. Prowse,et al.  Atlantic salmon (Salmo salar) in winter: "the season of parr discontent"? , 1998 .

[26]  R. Saunders.  Ecology and Management of Atlantic Salmon , 1991 .