Aquatic Sciences

, Volume 69, Issue 2, pp 240–256

Effects of alpine hydropower operations on primary production in a downstream lake

  • David Finger
  • Peter Bossard
  • Martin Schmid
  • Lorenz Jaun
  • Beat Müller
  • Daniel Steiner
  • Erwin Schäffer
  • Markus Zeh
  • Alfred Wüest
Research Article

DOI: 10.1007/s00027-007-0873-6

Cite this article as:
Finger, D., Bossard, P., Schmid, M. et al. Aquat. Sci. (2007) 69: 240. doi:10.1007/s00027-007-0873-6

Abstract.

During the past century, the construction of hydropower dams in the watershed of Lake Brienz has significantly altered the dynamics of turbidity, which has important implications for lake productivity. To assess these effects, we measured in situ carbon assimilation rates and ambient light intensities over 18 months. Based on experimental data, a numerical model was developed to assess gross primary production under present light conditions and those under a hypothetical case without upstream dams. Light conditions for the hypothetical ‘no-dam’ situation were estimated from pre-dam Secchi depths and simulated ‘no-dam’ particle concentrations. Current gross primary production is low (~66 gC m−2 yr−1), and could increase ~44% if the lake was less turbid. Disregarding nutrient retention in reservoirs, we estimate gross primary production would be ~35% lower in summer and ~23% higher in winter in the absence of reservoirs. The annual primary production (~58 gC m−2 yr−1) would decrease ~12% compared to the current primary production with dams. According to model calculations, hydropower operations have significantly altered the seasonal dynamics, but have little effect on annual primary production in Lake Brienz.

Keywords.

Dams and reservoirs downstream effects turbid lakes light regime oligotrophic lakes 

Copyright information

© Eawag, Dübendorf 2007

Authors and Affiliations

  • David Finger
    • 1
    • 2
  • Peter Bossard
    • 3
  • Martin Schmid
    • 1
  • Lorenz Jaun
    • 1
  • Beat Müller
    • 1
  • Daniel Steiner
    • 3
  • Erwin Schäffer
    • 4
  • Markus Zeh
    • 5
  • Alfred Wüest
    • 1
    • 2
  1. 1.Surface Waters – Research and ManagementSwiss Federal Institute of Aquatic Science and Technology, EawagKastanienbaumSwitzerland
  2. 2.Institute of Biogeochemistry and Pollutant DynamicsETH ZürichZürichSwitzerland
  3. 3.Aquatic EcologySwiss Federal Institute of Aquatic Science and Technology, EawagKastanienbaumSwitzerland
  4. 4.Fish Ecology and EvolutionSwiss Federal Institute of Aquatic Science and Technology, EawagKastanienbaumSwitzerland
  5. 5.Laboratory for Water and Soil Protection of the Canton of Bern (GBL)BernSwitzerland

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