Abstract Fine‐grained sediment is a natural and essential component of river systems plays major role in the hydrological, geomorphological ecological functioning rivers. In many areas world, level anthropogenic activity such that fine‐grained fluxes have been, or are being, modified at magnitude rate cause profound, sometimes irreversible, changes way function. This paper examines how has caused significant quantity quality within systems, using examples of: land use change New Zealand;...

The performance is tested of 12 bed load sediment transport formulae developed for use in gravel channels. are applied the manner intended by original authors. To this end, test data restricted to ones obtained approximately steady flow when material motion was similar that present on bed; is, not size selective. This represents nearest approach “equilibrium transport” can be realized with available data. Four sets river and three flume were chosen test, covering a range eight orders...

Characteristics of the suspended sediment load in Waipaoa River, New Zealand, and two its tributaries (Mangatu Te Arai Rivers) are examined for evidence different dominant erosion processes basins upstream. Different shapes concentration‐water discharge relations lead to differences long‐term average yield, event‐yield magnitude‐frequency relations, relative importance large flows rare events. In Mangatu frequent runoff events relatively more important yield (11,540 t km −2 yr −1 ), half is...

Abstract Temporal variations in bedload transport rates that occur at a variety of timescales, even under steady flow conditions, are accepted as an inherent component the process. Rarely, however, has cause such been explained clearly. We consider three data sets, obtained from laboratory experiments, refer to measurements made with continuously recording traps. Each set is characterized by predominant low‐frequency oscillation, on which additional higher‐frequency oscillations generally...

Abstract Human‐induced modifications of the vegetation cover in river basins may cause strong geomorphic responses by disturbing sediment supply, transport and deposition regimes. The response is particularly noticeable upland regions, where sensitivity to change enhanced coupling between channels hillslopes, as exemplified studies undertaken East Coast region, North Island, New Zealand, Southern French Prealps. Both regions have been affected land‐use during past 150 years (deforestation...

The methodology and errors involved in determining the amount of sediment produced during two (19·5 33·2 year) periods by 11 (c. 0·01 − >0·20 km2) gullies within a 4 km2 area headwaters Waipaoa River basin, New Zealand, using sequential digital elevation models are described. Sediment production from all study was 0·99 ± 0·03 × 106 t a−1 (2480 80 ha−1 a−1) period 1939 to 1958. It declined 0·62 0·02 (1550 50 1958 1992, when many smaller were stabilized programme afforestation, which commenced...

The 1993 flood on the Upper Mississippi River was a rare, large‐magnitude hydrological event. Field and aerial survey analyses Landsat 5 Thematic Mapper data were used to appraise thickness of overbank deposits leveed unleveed reaches. Results indicate that minimal (<5 mm) sedimentation occurred, except in immediate vicinity levee break. Unleveed sections also lacked sedimentation. Little geomorphological or sedimentological evidence this extreme event is likely be preserved. This raises...

Downstream changes in particle size that occur the Waipaoa River, a 104‐km‐long gravel bed river which rapid aggradation historic (post‐1800) period was triggered by conversion of native forest to pasture, are summarized this paper. The textural data presented unique for field situation, not only because spatial resolution and extent sampling program but also they provide information about pattern fining at different points time. They supported equally comprehensive topographic survey from...

Steepland rivers draining small, coastal watersheds often have very high suspended sediment loads, but the event characteristics of concentration and yield in this class river is not well documented. Continuous monitoring at four sites Waipaoa River basin, New Zealand, demonstrates that during individual composite events, versus water discharge relations typically show clockwise hysteresis maximum poorly related to peak discharge. The signature different erosion processes also imprinted on...

We compute the particulate organic carbon (POC) yield of Waipaoa River, New Zealand, using sediment rating curves in conjunction with measurements content suspended sediment. To ascertain source and extent to which POC flux is tied different erosion processes, we determined stable isotopic composition (δ 13 C) nitrogen (C/N) ratio weathered bedrock, soil, regolith. Most derived from generated by gully (incision into bedrock), supplemented landsliding during extreme events. The specific...

Research Article| November 01, 1995 Sediment characteristics of an extreme flood: 1993 upper Mississippi River valley Basil Gomez; Gomez 1Department Geography and Geology, Indiana State University, Terre Haute, 47809 Search for other works by this author on: GSW Google Scholar L. A. K. Mertes; Mertes 2Department Geography, University California, Santa Barbara, California 93106 J. D. Phillips; Phillips 3Department East Carolina Greenville, North 27858 F. Magilligan; Magilligan 4Department...

We derive a sediment budget for Te Weraroa Stream, New Zealand, the principal drainage in small (29 km 2 ) steepland catchment where gully erosion, triggered by conversion to pasture early twentieth century, was ameliorated reforestation that commenced 1962. Estimates of production were made using change area observed sequential aerial photographs. Channel storage assessed from stream cross‐section surveys. At its peak, erosion affected ∼6% total area. The amount contributed gullies declined...

Abstract The quantitative bedload transport data that are presently available confirm the generalized rate‐stream power relationship is applicable to natural streams. However, rate not solely dependent upon hydraulic parameters, but also inter‐relationship between bed material characteristics and flow properties. Segregation of surficial material, as expressed through development an armour coat, limits availability transportable material. Under such circumstances observed rates less than...

HydroTrend, a hydrologic‐transport model, is used to simulate the water and suspended sediment discharge of Waipaoa River system over last 3 Kyr, time period in which well‐documented sequence natural events anthropogenic activities that profoundly impacted drainage basin processes occurred. Comparisons between observed simulated data show model output replicates frequency distribution flow concentration‐discharge relationship, long‐term trends are consistent with record preserved on middle...

Patterns of overbank sedimentation in the vicinity of, and far removed from, levee breaks that occurred response to >100 year, summer 1993 flood upper Mississippi River valley are elucidated. Two suites deposits were associated with failure artificial levees within a 70 km long study reach. Circumjacent sand component break complex develops immediate site. As epitomized by at Sny Island, these features consist an erosional, scoured and/or stripped zone, together horseshoe-shaped,...

Abstract Following clearance of the indigenous forest and conversion land to pasture early in 20th century, gully erosion became a pervasive feature headwaters Waipaoa River basin, was notably problematic 140‐km 2 area now covered by Mangatu Forest. In this area, before reforestation 1961, affected c . 4% terrain. After 24‐year exotic programme gullies reduced 1.5%, but eight larger than 10 ha 1960 none had stabilized 1988, although four at least halved size. Estimates that will stabilize or...

Research Article| August 01, 2004 El Niño–Southern Oscillation signal associated with middle Holocene climate change in intercorrelated terrestrial and marine sediment cores, North Island, New Zealand Basil Gomez; Gomez 1Geomorphology Laboratory, Indiana State University, Terre Haute, 47809, USA Search for other works by this author on: GSW Google Scholar Lionel Carter; Carter 2National Institute of Water Atmospheric Research, P.O. Box 14901, Wellington, Noel A. Trustrum; Trustrum 3Institute...

A new chronology of large magnitude rainfall events derived from the continuous high-resolution Lake Tutira storm sediment record covers last 6800 years and provides first insight into changes in El Niño-Southern Oscillation (ENSO) teleconnections to higher southern latitudes be obtained New Zealand. Synthesis with independent paleoclimate records tropical Pacific Antarctica also reveals a millennial-scale waxing waning that were not visible narrow historical window previously used view...

The rate of vertical accretion (typically 14–18 mm h−1) during eight floods in the Waipaoa River basin, with recurrence intervals 5 to 60 years, was determined by relating floodplain stratigraphy at McPhail's bend 1948–1995 flood history. Overbank deposits remaining after a that occurred March 1996 suggest 15 h−1. By contrast, because flow velocity across too high permit deposition from suspension, record 1988 only 6 sequence is highly discontinuous, and rapid response late 19th early 20th...