Seasonal Accumulation and Depletion of Local Sediment Stores of Four Headwater Catchments

Abstract

Seasonal turbidity patterns and event-level hysteresis analysis of turbidity verses discharge in four 1 km 2 headwater catchments in California's Sierra Nevada indicate localized in-channel sediment sources and seasonal accumulation-depletion patterns of stream sediments. Turbidity signals were analyzed for three years in order to look at the relationships between seasonal turbidity trends, event turbidity patterns, and precipitation type to stream sediment production and transport. Seasonal patterns showed more turbidity events associated with fall and early to mid-winter events than with peak snow-melt. No significant turbidity patterns emerged for periods of snow melt vs. rain. Single event hysteresis loops showed clockwise patterns were dominant suggesting local sediment sources. In successive discharge events, the largest turbidity spike was often associated with the first but not necessarily the largest discharge event-indicating seasonal depletion of local sediment stores. In multi-peaked discharge events, hysteresis loops shifted from clockwise to linear or random patterns suggesting that localized sediment stores are being used up and sufficient flow energy must be reached to start entraining the more consolidated bank/bed sediment or that dominant sediment sources may be shifting to less localized areas such as hill slopes. A conceptual model with phases of accumulation and transport is proposed.

Spatiotemporal variations of suspended sediment transport in the upstream and midstream of the Yarlung Tsangpo River (the upper Brahmaputra), China

“…This pattern indicated high correlation between discharge and sediment concentration. A linear pattern was reported as a reflection of a lower entrainment threshold (Martin et al, 2014), which was supported by lower flow velocity and lower transport capacity at the station.…”

“…The exponent b was used as an index reflecting sediment transport capacity of water flow and a higher b-value could mean higher sediment transport capacity (Walling, 1974;Asselman, 2000). A linear pattern was reported as a reflection of a lower entrainment threshold (Martin et al, 2014), which was supported by lower flow velocity and lower transport capacity at the station. This partly explained the dominant sediment contribution from the two stretches, although precipitation and runoff depth in both stretches were not the largest.…”

Characterizing and explaining spatio-temporal variation of water quality in a highly disturbed river by multi-statistical techniques

“…Higher percentages of the urban land generally cause an increase in COD concentration in the dry winter, while higher forest lands with sporadic human activity disturbance causes an elevated COD level during the wet season. Unexpectedly, most rural areas report a high COD concentration in pre-flood months probably as the result of seasonal scale first flush phenomenon (Martin et al 2014 ). Soller et al ( 2005 ) suggested that the serious diffuse pollution is a function of storm intensity and long antecedent dry period.…”

Relationships between Sediment Transport and Various Hydrological and Hydraulic Characteristics of Flood Events on Trotuș River (Romania)

“…In such floods (e.g., 2004,2005,2010 and 2016, all type B), with large duration and several peaks, a shift was documented in hysteresis loops, depending on the source areas, thus generating a complex model. Martin et al (2014) [76] show that these hysteresis pattern changes can be attributed to one of two scenarios: (i) either a shift occurs from easily erodible channel material to more cohesive bed or bank material, or (ii) a transition from the channel and its proximal source area to the slopes. Type II hysteresis loops account for a significant share of the total number of D type floods (25% or 13 flood events), therefore confirming that this type is specific to moderate floods with limited flow discharge, low sediment yield and high SSC [73,75,77].…”