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Hydrological Processes (2008)
  • Eric Wade Peterson
  • Timothy Sickbert
  • Suzanna L Moore
Abstract
Little Kickapoo Creek (LKC), a low-gradient stream, mobilizes its streambed–fundamentally altering its near-surface hyporheic zone–more frequently than do higher-gradient mountain and karst streams. LKC streambed mobility was assessed through streambed surveys, sediment sampling, and theoretical calculations comparing basal shear stress (τb) with critical shear stress (τc). Baseflow τb is capable of entraining a d50 particle; bankfull flow could entrain a 51·2 mm particle. No particle that large occurs in the top 30 cm of the substrate, suggesting that the top 30 cm of the substrate is mobilized and redistributed during bankfull events. Bankfull events occur on average every 7·6 months; flows capable of entraining d50 and d85 particles occur on average every 0·85 and 2·1 months, respectively. Streambed surveys verify streambed mobility at conditions below bankfull. While higher gradient streams have higher potential energy than LKC, they achieve streambed-mobilization thresholds less frequently. Heterogeneous sediment redistribution creates an environment where substrate hydraulic conductivity (K) varies over four orders of magnitude. The frequency and magnitude of the substrate entrainment has implications on hyporheic zone function in fluid, solute and thermal transport models, interpretations of hyporheic zone stability, and understanding of LKC's aquatic ecosystem
Keywords
  • sediment transport,
  • • low-gradient stream,
  • hyporheic zone,
  • groundwater/surface-water relations
Disciplines
Publication Date
October, 2008
DOI
10.1002/hyp.7031
Citation Information
Peterson, E. W., Sickbert, T. B. and Moore, S. L. (2008), High frequency stream bed mobility of a low-gradient agricultural stream with implications on the hyporheic zone. Hydrol. Process., 22: 4239–4248. doi: 10.1002/hyp.7031