Application of H218O/H216O Abundances to the Problem of Lateral Mixing in the Liard–Mackenzie River System

1971 ◽  
Vol 8 (9) ◽  
pp. 1107-1109 ◽  
Author(s):  
H. R. Krouse ◽  
J. Ross Mackay
Keyword(s):  
River System ◽  
Cross Sectional ◽  
Lateral Mixing ◽  
Mackenzie River

Relative H218O/H216O abundances were determined in 10 cross-sectional profiles of the Liard–Mackenzie River system sampled during June, 1970 at various intervals over 300 miles (480 km) distance downstream from their confluence. At their confluence, the Liard and the Mackenzie Rivers had average δH218O values of −21.3‰ and −17.4‰ SMOW respectively. Thus, lateral mixing of the two waters could be monitored isotopically. The data show that a distance of the order of 200 miles (320 km) was required for thorough lateral mixing.

Application of Water Temperatures to the Problem of Lateral Mixing in the Great Bear–Mackenzie River System

1972 ◽  
Vol 9 (7) ◽  
pp. 913-917 ◽  
Author(s):  
J. Ross Mackay
Keyword(s):  
River System ◽  
Temperature Profiles ◽  
Mackenzie Delta ◽  
River Temperature ◽  
Cross River ◽  
Lateral Mixing ◽  
Bear River ◽  
Better Than ◽  
Good Agreement ◽  
Mackenzie River

Cross-river temperature profiles were run in mid-June 1971 at approximately 20 km intervals from the confluence of the Great Bear and Mackenzie Rivers, at Fort Norman, N.W.T., to the Mackenzie Delta, a distance of 650 km. As the Great Bear River was cold, the Mackenzie River warm, and as temperatures were read to better than ±.01 °C in the field, the cross-profiles have provided a record of the lateral mixing of the two rivers. A flow distance of 500 km was required for nearly complete mixing. The 1971 cross-river temperature profiles and aerial infrared imagery taken in 1969 show a good agreement in the mixing pattern. It is suggested that where water temperature contrasts exist, temperatures, which can be read easily with a resolution of better than ±.01 °C, may serve as one of the easiest and most economical of the tracers suitable for mixing studies.

New Complexities in Zoogeography and Taxonomy of the Pygmy Whitefish (Prosopium coulteri)

1972 ◽  
Vol 29 (12) ◽  
pp. 1772-1775 ◽  
Author(s):  
C. C. Lindsey ◽  
W. G. Franzin
Keyword(s):  
River System ◽  
Yukon Territory ◽  
Hudson Bay ◽  
The South ◽  
Bristol Bay ◽  
River Drainage ◽  
Bay Area ◽  
First Time ◽  
Mackenzie River

Pygmy whitefish (Prosopium coulteri) are recorded for the first time from the Peel–Mackenzie river drainage (Elliott Lake, Yukon Territory) and from the Hudson Bay drainage (Waterton Lakes, Alberta, in the South Saskatchewan–Nelson river system). The morphology of specimens from both localities contradicts the previously known pattern of a southeastern "low-rakered" and a northwestern "high-rakered" form (with the two forms occurring sympatrically in some lakes of the Bristol Bay area). Specimens from Elliott Lake, the most northerly known locality, resemble the southeastern form and those from Waterton Lakes the northwestern form. Both Waterton and Elliott lakes lie close to unglaciated refugia, suggesting that the species may have survived Wisconsin glaciation and diverged in several different watersheds.

Increasing discharge from the Mackenzie River system to the Arctic Ocean

2016 ◽  
Vol 31 (1) ◽  
pp. 150-160 ◽  
Author(s):  
Stewart B. Rood ◽  
Sobadini Kaluthota ◽  
Laurens J. Philipsen ◽  
Neil J. Rood ◽  
Karen P. Zanewich
Keyword(s):  
Arctic Ocean ◽  
River System ◽  
The Arctic ◽  
The Arctic Ocean ◽  
Mackenzie River

The hydrologic regime of Mackenzie River and connection of "no-closure" lakes to distributary channels in the Mackenzie Delta, Northwest Territories

1995 ◽  
Vol 32 (7) ◽  
pp. 926-937 ◽  
Author(s):  
C. R. Burn
Keyword(s):  
Water Level ◽  
Drainage Basin ◽  
Late Summer ◽  
River System ◽  
Water Levels ◽  
Ice Thickness ◽  
Mackenzie Delta ◽  
Lake Ice ◽  
Discharge System ◽  
Mackenzie River

Mackenzie Delta lakes have been classified by the seasonal duration of their connection to Mackenzie River. "No-closure" lakes are determined on the basis of minimum summer water level. Such lakes may become disconnected from the Mackenzie in autumn or winter, as water level falls or if the sills between lakes and distributary channels are frozen through and so sealed. Water level in the central delta rises continuously after late November–early December, at first because discharge into the delta increases once the Mackenzie drainage basin has frozen over, and then as sea and channel ice thickens in the outer delta, impounding discharge. Since 1973 this seasonal increase in stage from its minimum in early December to the level on 1 April has been between 29 and 95 cm. Between 1987 and 1994, the rise in stage near Inuvik has been slightly greater than increases in lake-ice thickness (30–68 cm). Channels and lakes that are connected to the Mackenzie discharge system in December may remain connected throughout winter. A critical sill elevation for connection of such lakes to the river system is the minimum stage minus mid-December ice thickness. Recently, these elevations have been from 1.0 to 1.6 m lower than late summer water levels. Lakes with sill elevations still lower may remain connected to the Mackenzie throughout the year. In 1993-1994, only 3 of 16 "no-closure" lakes surveyed near Inuvik remained open to the Mackenzie discharge throughout winter, representing 2% of the lakes in this portion of the delta.

River discharge, sedimentation, and benthic environmental variations in Miramichi Inner Bay, New Brunswick

1983 ◽  
Vol 20 (3) ◽  
pp. 388-398 ◽  
Author(s):  
C. T. Schafer ◽  
J. N. Smith
Keyword(s):  
New Brunswick ◽  
River Discharge ◽  
River System ◽  
Circulation Pattern ◽  
Foraminiferal Assemblage ◽  
Cross Sectional ◽  
Tidal Circulation ◽  
The Past ◽  
Environmental Variations ◽  
Sequential Studies

Sequential studies of benthonic foraminifera in the Miramichi estuary, New Brunswick over a 12 year period indicate that a "transitional" foraminiferal assemblage, which defines a zone of interaction of river and open bay environmental factors, has developed in Miramichi Inner Bay since 1964. Abundance variations of the transitional foraminiferal indicator species Ammotium cassis relative to Miliammina fusca (upper estuarine indicator) and Elphidium excavatum forma clavata (marginal marine indicator) in short cores suggest that the regional extent of this transitional thanatotope in the western part of Miramichi Inner Bay has varied considerably during the past 80–100 years. These changes appear to be related to total annual river discharge variations, competence of the Miramichi River system, and. possibly, changes in the tidal circulation pattern of bay water. Tidal circulation may have been altered by the location and cross-sectional area of several channels that occur between the barrier islands on the seaward side of the bay.

Planform deviations in river channel alignment due to active landsliding in the High Himalaya of Bhutan

2020 ◽  
Author(s):  
Larissa de Palézieux ◽  
Kerry Leith ◽  
Simon Loew
Keyword(s):  
Large Scale ◽  
Rock Slope ◽  
River System ◽  
River Channel ◽  
Point Sources ◽  
River Channels ◽  
Stream Network ◽  
Cross Sectional ◽  
Slope Instabilities

<p>Large rock slope instabilities affect river channels both due to catastrophic failures and long-term creep. The relationship between rock slop instabilities and processes in the adjacent river system are typically assessed in terms of channel profile perturbations and cross-sectional morphology, e.g. excess topography. However, such relationships can also be evident in planform changes of the channel alignment, e.g. in landslide dams and long-term channel migration. Large scale creeping rock slope instabilities can be considered point sources which introduce sediment laterally to a river channel. In cases in which sediment production from one side of the channel exceeds that of the opposing side, the course of the river can be shifted towards the less active hillslope. The deviation of the channel from its original course may therefore be used as a proxy for relative sediment input of the two opposing hillslopes.</p><p>In order to characterize the planform morphology of the river channels, we treat them as signals fluctuating around a smoothed channel and use a fast Fourier transform to extract characteristic wavelengths and amplitudes of the stream network. We observe a consistent increase in amplitude of planform deviation with increasing wavelength with a variability of two orders of magnitude at the shortest wavelength (10<sup>1</sup> m) and less than one order of magnitude at longer wavelengths (10<sup>3</sup> m).</p><p>When comparing characteristic channel morphologies based on these analyses to the deviation of channels adjacent to mapped landslides, the amplitude of the deviation appears higher than those naturally occurring in the river system at wavelengths similar to twice the landslide width.</p>

The Mackenzie River system

1986 ◽  
pp. 425-540 ◽  
Author(s):  
D. M. Rosenberg ◽  
D. R. Barton ◽  
G. J. Brunskill ◽  
P. J. McCart
Keyword(s):  
River System ◽  
Mackenzie River

Genetic population structure of broad whitefish, Coregonus nasus, from the Mackenzie River, Northwest Territories: implications for subsistence fishery management

2010 ◽  
Vol 67 (6) ◽  
pp. 905-918 ◽  
Author(s):  
Les N. Harris ◽  
Eric B. Taylor
Keyword(s):  
Northwest Territories ◽  
Fishery Management ◽  
Management Strategies ◽  
River System ◽  
Population Subdivision ◽  
Genetic Population ◽  
Dna Variation ◽  
Scale Population ◽  
Population Structuring ◽  
Mackenzie River

We assayed microsatellite DNA variation among 1013 broad whitefish, Coregonus nasus , from 36 localities within the lower Mackenzie River (Northwest Territories, Canada) to provide the first assessment of fine-scale population structuring of broad whitefish in this large system. Among sampling locations, averaged across all loci, the number of alleles ranged from 3.00 to 6.71 and heterozygosity averaged 0.54. Population subdivision was generally low, but significant (θ = 0.026, P < 0.05), although pairwise comparisons indicated that overall significance was heavily influenced by comparisons between anadromous and lacustrine groups. Bayesian-based STRUCTURE analysis suggested that there are two main genetic groups within our study area: anadromous and lacustrine broad whitefish. A mixture analysis indicated that all populations contribute to the lower Mackenzie River subsistence fishery, yet catches were dominated by Peel River fish, highlighting the importance of this tributary. Our data also supported the idea that there are several units of conservation among Mackenzie River system broad whitefish populations and that management strategies should be implemented accordingly.

scholarly journals Artisanal Fisheries in the Ndumo Area of the Lower Phongolo River Floodplain, South Africa

Koedoe ◽  
2015 ◽  
Vol 57 (1) ◽  
Author(s):  
Hendri C. Coetzee ◽  
Werner Nell ◽  
Elize S. Van Eeden ◽  
Engela P. De Crom
Keyword(s):  
South Africa ◽  
Survey Design ◽  
Clarias Gariepinus ◽  
River System ◽  
Fish Populations ◽  
Artisanal Fisheries ◽  
Cross Sectional ◽  
River Floodplain ◽  
Conservation Implications ◽  
The Impact

The aim of this study was to investigate the status of artisanal fisheries in the lower Phongolo River floodplain in northern KwaZulu-Natal, South Africa. A cross-sectional quantitative survey design was used that included the development of a questionnaire and a systematic survey among the five villages bordering the Ndumo Game Reserve. Data were collected over a 5-day period by a group of 16 fieldworkers and analysed using the Statistical Package for the Social Sciences, version 21. The results revealed that fish was the third most consumed protein in the area, that people consumed fish on average twice a week, that at least six fish species (and one recently introduced crayfish species) were consumed regularly, and that most fish were obtained from local vendors, who in turn bought it from local fishermen and -women. Fishing activities also appeared to occur predominantly along the river system and targeted mainly red-breasted tilapia (Tilapia rendalli) and Mozambique tilapia (Oreochromis mossambicus) and, to a slightly lesser extent, African sharptooth catfish (Clarias gariepinus) and brown squeaker (Synodontis zambezensis).Conservation implications: Given that Ndumo residents predominantly catch fish by means of non-commercial methods, that they do so for reasons of personal consumption and subsistence, and that they mostly target rivers and dams rather than the ecologically sensitive pans in the region, it would seem likely that fishing in the region might be sustainable for the moment. However, it is recommended that studies on the local fish populations and their reproductive rates be conducted so that the actual impact on local fish populations can be determined more accurately. This study serves to provide the necessary baseline data on fish utilisation in the region, which would enable the impact of artisanal fishing on fish reserves in the Ndumo region to be determined once population studies have been completed.

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