Natural Siltation of Brown Trout (Salmo trutta L.) Spawning Gravels During Low-Flow Conditions

  • P. A. Carling
  • C. P. McCahon


Deposits of gravel in upland streams are a valuable ecological resource used by salmonid fish for spawning. Most of these gravels exhibit two distinct modes in the grain-size distribution. Generally the coarse mode is dominant and forms the framework of the deposit whilst a secondary mode, referred to as the matrix, consists of finer sediments (Carling & Reader 1982) which fill or partially fill the interstitial spaces between the framework particles. These fine sediments, if present in sufficient quantity, will cause a reduction in porosity and hydrostatic permeability, so that the volume of water held within the deposit and the intragravel velocity will be reduced. Consequently, oxygen supply-rates to fish eggs and the rate of removal of metabolic waste products will fall; possibly to lethal levels. Although some of these latter aspects have been investigated (Milner et al. 1981) the mechanisms by which bimodal gravel deposits form are poorly understood. Gravels characterized by an absence of matrix are termed open-work gravels (Cary 1951). Deposition of coarse and fine sediments may occur contemporaneously but this is not common (Fraser 1935); usually such deposits are characterised by a dilated framework whereby the matrix forms at least 20 to 30% of the deposit and would require a sudden reduction in sediment transport energy to develop (Dyer 1972). More usually in fluvial systems subject to steady changes in transportation energy, coarse particles are deposited first whilst fine material is held in suspension. Consequently the matrix in bimodal deposits usually fills the void space within the coarse deposit by a process of secondary infiltration of the stable bed (Smith 1974).


Deposition Rate Suspended Sediment Brown Trout Fine Sediment Suspend Sediment Concentration 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Adams, J. N. & Beschta, R. L. 1980. Gravel bed composition in Oregon coastal streams. Can. J. Fish. Aquat. Sci. 37: 1514–1521.CrossRefGoogle Scholar
  2. Beschta, R. L. & Jackson, W. L. 1979. The intrusion of fine sediments into a stable gravel bed. J. Fish. Res. Board Can. 36: 204–210.CrossRefGoogle Scholar
  3. Carling, P. A. 1983. Particulate dynamics, dissolved and total load, in two small basins, northern Pennines, U.K. Hydrol. Sci. J. 28: 355–375.CrossRefGoogle Scholar
  4. Carling, P. A. 1984a. Deposition of fine and coarse sand in an open-work gravel bed. Can. J. Fish. Aquat. Sci. 41: 263–270.CrossRefGoogle Scholar
  5. Carling, P. A. 1984b. Comparison of suspended sediment rating curves obtained using two sampling methods. In: Channel Processes — Water, Sediment, Catchment Controls. (Ed by A.P. Schick). Catena Suppl. 5: 43–49.Google Scholar
  6. Carling, P. A. & Reader, N. A. 1982. Structure, composition and bulk properties of upland stream gravels. Earth Surf. Processes Landforms 7: 349–365.CrossRefGoogle Scholar
  7. Carling, P. A. & Hurley, M. A. in press. A time-varying stochastic model of the frequency and magnitude of bedload transport events in two small trout streams. In: Problems of Sediment Transport in Gravel-Bed Rivers (Ed by C. R. Thorne, J. C. Bathurst & R. D. Hey). Wiley, Chichester.Google Scholar
  8. Cary, A. S. 1951. Origin and significance of open-work gravel. Trans. Am. Soc. civ. Engrs. 116: 1296–1308.Google Scholar
  9. Culling, W. E. H. 1963. Soil creep and the development of hillside slopes. J. Geol. 71 127–161.CrossRefGoogle Scholar
  10. Dixon, W. J. & Massey, F. J. 1969. Introduction to statistical analysis. McGraw-Hill, New York. 488 pp.Google Scholar
  11. Dyer, K. R. 1972. Bed shear stresses and the sedimentation of sandy gravels. Mar. Geol. 13: M31–M36.CrossRefGoogle Scholar
  12. Egglishaw, H. J. 1964. The distributional relationship between the bottom fauna and plant detritus in streams. J. Anim. Ecol. 33: 463–476.CrossRefGoogle Scholar
  13. Einstein, H. A. 1968. Deposition of suspended particles in a gravel bed. J. Hydr. Div., Am. Soc. civ. Engr. 94: 1197–1205.Google Scholar
  14. Fraser, H. J. 1935. Experimental study of porosity and permeability of clastic sediments. J. Geol. Chicago 43: 910–1010.Google Scholar
  15. Fraser, J. C. 1972. Regulated stream discharge for fish and other aquatic resources — an annotated bibliography. F.A.O. Fish. Tech. Pap. 112: 103 pp.Google Scholar
  16. Frostick, L. E., Lucas, P. M. & Reid, I. 1984. The infiltration of fine matrices into coarse-gravel alluvial sediments and its implications for stratigraphical interpretation. J. Geol. Soc. 141: 955–965.CrossRefGoogle Scholar
  17. Ikeda, H. 1982. An experimental study of the formation of open-work gravel layers under alluvial flow conditions. Trans. Japan Geomorph. Un. 3: 57–65.Google Scholar
  18. Iwamoto, R. N., Salo, E. O., Madej, M. A., McComas, R. L. & Rulifson, R.L. 1978. Sediment and water quality: a review of the literature including a suggested approach for water quality criteria with summary of workshop and conclusions and recommendations. U.S. Environ. Prot. Agency 910/9-78-048, 151 pp.Google Scholar
  19. Luedthe, R. J. & Brusven, M. A. 1976. Effects of sand sedimentation on colonization of stream insects. J. Fish. Res. Board Can. 33: 1181–1886.Google Scholar
  20. Milner, N. J., Scullion, J., Carling, P. A. & Crisp, D. T. 1981. The effect of discharge on sediment dynamics and consequent effects on invertebrates and salmonids in upland rivers. Adv. Appl. Biol. 6: 153–220.Google Scholar
  21. Ottaway, E. M., Carling, P. A., Clarke, A., & Reader, N. A. 1981. Observations on the structure of brown trout, Salmo trutta Linnaeus, redds. J. Fish Biol. 19: 593–607.CrossRefGoogle Scholar
  22. Smith, N. D. 1974. Sedimentology and bar formation in the upper Kicking Horse river, a braided outwash stream. J. Geol. 82: 205–223.CrossRefGoogle Scholar
  23. Welch, D. M. 1973. Channel form and bank erosion, Red River, Manitoba, pp. 284–293. In: Fluvial Processes and Sedimentation, pp. 759. Proc. Hydrol. Symp. Univ. Alberta, Edmonton, Nat. Res. Council Canada.Google Scholar
  24. Welton, J. S. 1980. Dynamics of sediment and organic detritus in a small chalk stream. Arch. Hydrobiol. 90: 162–181.Google Scholar

Copyright information

© Plenum Press, New York 1987

Authors and Affiliations

  • P. A. Carling
    • 1
  • C. P. McCahon
    • 1
  1. 1.Freshwater Biological AssociationThe Ferry HouseAmbleside, CumbriaUK

Personalised recommendations