Implications of climate change on flow regime affecting Atlantic salmon

Abstract. The UKCIP02 climate change scenarios (2070–2100) suggest that the UK climate will become warmer (an overall increase of 2.5–3°C), with temperature increases being greater in the summer and autumn than in the spring and winter seasons. In terms of precipitation, winters are expected to become wetter and summers drier throughout the UK. The effect of changes in the future climate on flow regimes are investigated for the Atlantic salmon, Salmo salar, in a case study in an upland UK river. Using a hydraulic modelling approach, flows simulated across the catchment are assessed in terms of hydraulic characteristics (discharge per metre width, flow depths, flow velocities and Froude number). These, compared with suitable characteristics published in the literature for various life stages of Atlantic salmon, enable assessment of habitat suitability. Climate change factors have been applied to meteorological observations in the Eden catchment (north-west England) and effects on the flow regime have been investigated using the SHETRAN hydrological modelling system. High flows are predicted to increase by up to 1.5%; yet, a greater impact is predicted from decreasing low flows (e.g. a Q95 at the outlet of the study catchment may decrease to a Q85 flow). Reliability, Resilience and Vulnerability (RRV) analysis provides a statistical indication of the extent and effect of such changes on flows. Results show that future climate will decrease the percentage time the ideal minimum physical habitat requirements will be met. In the case of suitable flow depth for spawning activity at the outlet of the catchment, the percentage time may decrease from 100% under current conditions to 94% in the future. Such changes will have implications for the species under the Habitats Directive and for catchment ecological flow management strategies.

[1]  R. J. White,et al.  Daytime Responses of Brown Trout (Salmo trutta) to Cover Stimuli in Stream Channels , 1978 .

[2]  J. Stedinger,et al.  Robustness of water resources systems , 1982 .

[3]  K. Beland,et al.  Water Depth and Velocity Preferences of Spawning Atlantic Salmon in Maine Rivers , 1982 .

[4]  M. Field,et al.  The meteorological office rainfall and evaporation calculation system -- MORECS , 1983 .

[5]  A. D. Pickering,et al.  A comparison of the effects of overhead cover on the growth, survival and haematology of juvenile Atlantic salmon, Salmo salar L., brown trout, Salmo trutta L., and rainbow trout, Salmo gairdneri Richardson , 1987 .

[6]  D. T. Crisp,et al.  Observations on siting, dimensions and structure of salmonid redds , 1989 .

[7]  J. Heggenes,et al.  Habitat utilization and preferences in juvenile atlantic salmon (salmo salar) in streams , 1990 .

[8]  T. G. Heggberget.  Some Environmental Requirements of Atlantic Salmon , 1991 .

[9]  G. Mathias Kondolf,et al.  The sizes of salmonid spawning gravels , 1993 .

[10]  R. Adams,et al.  Assessing the Performance of the NELUP Hydrological Models for River Basin Planning , 1995 .

[11]  John Ewen,et al.  Validation of catchment models for predicting land-use and climate change impacts. 1. Method , 1996 .

[12]  Charles C. Coutant,et al.  A GENERAL PROTOCOL FOR RESTORATION OF REGULATED RIVERS , 1996 .

[13]  David P. Braun,et al.  A Method for Assessing Hydrologic Alteration within Ecosystems , 1996 .

[14]  J. Bathurst,et al.  SHESED: a physically based, distributed erosion and sediment yield component for the SHE hydrological modelling system , 1996 .

[15]  Rebecca J. Lunn,et al.  DEVELOPMENT AND APPLICATION OF A NITROGEN MODELLING SYSTEM FOR LARGE CATCHMENTS , 1996 .

[16]  N. Poff,et al.  A hydrogeography of unregulated streams in the United States and an examination of scale‐dependence in some hydrological descriptors , 1996 .

[17]  D. Houlihan,et al.  Global Warming: The effect of temperature on protein metabolism in fish: the possible consequences for wild Atlantic salmon ( Salmo salar L.) stocks in Europe as a result of global warming , 1997 .

[18]  David P. Braun,et al.  How much water does a river need , 1997 .

[19]  C. Soulsby,et al.  Hydraulic and sedimentary characteristics of habitat utilized by Atlantic salmon for spawning in the Girnock Burn, Scotland , 1998 .

[20]  J. M. Elliott,et al.  Predicting fluctuations in the size of newly emerged sea‐trout fry in a Lake District stream , 1998 .

[21]  Richard N. Palmer,et al.  Water Resources Implications of Global Warming: A U.S. Regional Perspective , 1999 .

[22]  V. Braithwaite,et al.  How juvenile Atlantic salmon, Salmo salar L., respond to falling water levels: experiments in an artificial stream , 1999 .

[23]  George F. McMahon.  Sustainability Criteria for Water Resource Systems , 1999 .

[24]  E. Hertwich,et al.  Technical Summary , 2022, The Ocean and Cryosphere in a Changing Climate.

[25]  A. Bardonnet,et al.  Freshwater habitat of Atlantic salmon (Salmo salar) , 2000 .

[26]  John Ewen,et al.  SHETRAN: Distributed River Basin Flow and Transport Modeling System , 2000 .

[27]  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 .

[28]  John Ewen,et al.  Modelling nitrate transport in the Slapton Wood catchment using SHETRAN , 2000 .

[29]  C. Soulsby,et al.  Hydraulic and sedimentary controls on the availability and use of Atlantic salmon (Salmo salar) spawning habitat in the River Dee system, north-east Scotland , 2002 .

[30]  D. Gilvear,et al.  Hydrology and the ecological quality of Scottish river ecosystems. , 2002, The Science of the total environment.

[31]  Dennis P. Lettenmaier,et al.  Long range experimental hydrologic forecasting for the eastern U.S. , 2002 .

[32]  Paul S. Kemp,et al.  Habitat requirements of Atlantic salmon and brown trout in rivers and streams , 2003 .

[33]  J. Olden,et al.  Redundancy and the choice of hydrologic indices for characterizing streamflow regimes , 2003 .

[34]  H. Fowler,et al.  Modeling the impacts of climatic change and variability on the reliability, resilience, and vulnerability of a water resource system , 2003 .

[35]  A. Jensen.  Atlantic salmon (Salmo salar) in the regulated River Alta: effects of altered water temperature on parr growth , 2003 .

[36]  D. T. Crisp,et al.  Environmental requirements of common riverine European salmonid fish species in fresh water with particular reference to physical and chemical aspects , 1996, Hydrobiologia.

[37]  H. Fowler,et al.  Using regional climate model data to simulate historical and future river flows in northwest England , 2007 .

[38]  N. L. Binbol,et al.  Hydrology and Water Resources , 2007 .

[39]  Hayley J. Fowler,et al.  Regional climate model data used within the SWURVE project – 1: projected changes in seasonal patterns and estimation of PET , 2007 .