Channel erosion surveys along TAPS route, Alaska, 1974

Loeffler, Robert M.; Childers, Joseph M.

doi:10.3133/70047450

Cited by 5 publications

(3 citation statements)

References 3 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The peak instantaneous dis charge of record of 818 m3/s at the gaging station on the Sagavanirktok River was the result of a summer storm on August 19, 1974. That value compares with a maximum evident flood discharge of 1750 m3/s meas ured by Childers and Jones (1975, table 1) at a site on the Sagavanirktok River 7.2 km upstream from the Lupine River confluence and a short distance downstream from site S2. Childers, Sloan, and Meckel (1973, p. 4) noted that the major flooding observed on the Sagavanirktok River in July 1961 may have formed the high-water marks observed in 1972 at a level 2 to 3 feet above the tops of the main channel banks.…”

Section: Effects Of Major Floodssupporting

confidence: 54%

Effects of permafrost on stream channel behavior in Arctic Alaska

Scott¹

1978

Professional Paper

View full text Add to dashboard Cite

Sites with drainage areas ranging from 88 to 12,200 km2 were monitored on five streams in northern Alaska during the breakup in 1976 to determine (1) the effects of frozen bed and bank material on channel behavior, and (2) the importance of the annual breakup flood in forming the channels of arctic streams. The thawing and concomitant erosion of channels varied with changes in bed-material size, channel pattern, drainage area, and climate. The response of channels to breakup flooding ranged from total permafrost control of channel processes, including both bed scour and lateral erosion, to only brief restriction of channel behavior early in the rise of the flooding. The watershed characteristic that appears to explain much of this variation is size of drainage area. Similar variation of channel response with these factors is believed to be responsible for diametrically opposite results reported from recent studies of the two problems posed above. Permafrost has been cited both as the cause of extreme stability and as the cause of un usual instability in arctic streams as compared to those elsewhere. That permafrost simplifies the study of arctic stream channels through its domination of the effects of other variables has been a common assumption. As a consequence, however, the generalizations based on a single stream or on similar streams have led to a spectrum of inconsistent results. This spectrum of previous results now ap pears potentially consistent. Comparisons of absolute rates of lateral erosion are not feasible, but it is likely that the net effect of the permafrost environment is to create greater channel stability than is found in unregulated streams of similar size in nonpermafrost environments. Combina tions of factors, particularly those that encourage high rates of thermo-erosional niching, can nevertheless cause rates of erosion that dictate caution in engineering design.

show abstract

Section: Effects Of Major Floodssupporting

confidence: 54%

Effects of permafrost on stream channel behavior in Arctic Alaska

Scott¹

1978

Professional Paper

View full text Add to dashboard Cite

show abstract

“…There is a significant history pertaining to the use of remotely captured imagery to measure changes in stream morphology and geometry (e.g. Brice, 1971;Childers & Jones, 1975;Williams, 1978 andHooke, 1984). Since these initial studies, a diverse variety of methods have been developed to measure planform changes in streams in remotely captured imagery.…”

Section: Measuring Planform Change Using Remote Imagerymentioning

confidence: 99%

Use of remote imagery to verify modelled streambank retreat rates

2017

Syme, G., Hatton MacDonald, D., Fulton, B. And Piantadosi, J. (Eds) MODSIM2017, 22nd International Congress on Modelling and Si

View full text Add to dashboard Cite

The Source Catchments model attributes fractions of the sediment load carried by the rivers discharging into the Great Barrier Reef (GBR) lagoon, to specific sources-namely, hillslope, gully and streambank erosion. This study was conceived to determine whether it was possible to derive estimates of streambank retreat rates in a river discharging into the GBR lagoon, by using remote imagery. This remote imagery was to be in the form of readily available historical aerial photographs and more recent satellite imagery. Any usable estimates of streambank retreat rates that were obtained, were to be evaluated in regard to their suitability for the verification of the algorithms in the streambank erosion module in the Source Catchments model. The streambank mapping exercise was undertaken using sets of historical aerial photographs and more recent satellite imagery covering some 150-kilometres in the middle reaches of the Mary River. This river carries a disproportionately large sediment load relative to its volumetric discharge. The Source Catchments model attributes this differentiating characteristic to above-average rates of streambank erosion in the Mary River. The likely inundation extents associated with bankfull discharge were delineated in the various sets of historical imagery. This process yielded a time series of bankfull discharge polygons covering the subject reaches. Estimates of bankfull width were then obtained by laying transects at 500-metre intervals along and at right angles to the river centerline, in each set of images. This provided measurements of bankfull width at each transect location in each polygon in the time series. Digital elevation data obtained from airborne LiDAR surveys was used to aid verification of the bankfull width estimates derived from contemporaneous remote imagery. Streambank retreat rates were then determined on the basis of the change in bankfull width in the intervals between the sets of images in the time series. The statistical significance of the long-term rate of streambank retreat at each transect location was assessed by fitting the non-parametric Theil-Kendall Robust Line to the data. Changes in bankfull width varied substantially along the studied reaches, but did show a somewhat remarkable lack of temporal variability at the various transect locations. Spatial variability appeared more closely related to stream sinuosity than it did to presence of upper storey riparian vegetation. Notwithstanding the observed uniformity of the long-term trends, temporarily accelerated streambank retreat rates were associated with major floods. This study confirmed that the streambank retreat rates in the Mary River are relatively high when compared to other rivers discharging into the GBR lagoon. Furthermore, the broadscale retreat rate values presently adopted in Source Catchments model were found to be reasonably accurate. However, at a finer scale the modelled and measured estimates of retreat rates were somewhat disparate. The nature of this study precluded definitive identi...

show abstract

“…With the exception of the Sagavanirktok River, all were investigated during previous years. Previous investigations for this study and background information for this report are contained in reports by Brice (1971), Childers (1972Childers ( , 1974, Childers and Jones (1975), and Doyle andChilders (1975, 1976).…”

mentioning

confidence: 99%

Channel erosion surveys along the TAPS route, Alaska, 1977

Loeffler¹,

Childers²

1977

Open-File Report

View full text Add to dashboard Cite

Channel surveys were made along the TAPS route during at the same 28 sites that were studied in 1976. In addition, a new site at pipeline mile 22 near Deadhorse (alignment No. 134) along the Sagavanirktok River was put under surveillance. Except for changes wrought by the completion of construction, most of the sites showed very little change. Significant events include: virtual completion of all construction activities along the pipeline, the pipeline start-up, and the breakup flood along the Sagavanirktok River which breached many river-training structures. In general, 1977 saw heavy flooding on the streams draining the north and south slopes of the Brooks Range and moderate flooding on streams further south. Aerial photogrammetric surveys were used again in 1977 on the same seven sites as in 1976. Results document the applicability of the method for channel erosion studies, especially those on large braided rivers. However, it requires engineering judgement and personal knowledge of the particular site to avoid being occasionally led to inaccurate conclusions.

show abstract

Channel erosion surveys along TAPS route, Alaska, 1974

Cited by 5 publications

References 3 publications

Effects of permafrost on stream channel behavior in Arctic Alaska

Effects of permafrost on stream channel behavior in Arctic Alaska

Use of remote imagery to verify modelled streambank retreat rates

Channel erosion surveys along the TAPS route, Alaska, 1977

Contact Info

Product

Resources

About