Sources of Chlorophenolic Compounds to the Fraser River Estuary

1988 ◽  
Vol 23 (1) ◽  
pp. 55-68 ◽  
Author(s):  
J. H. Carey ◽  
J. H. Hart
Keyword(s):  
River Flow ◽  
River Estuary ◽  
Low Flow ◽  
Fraser River ◽  
Pulp Mills ◽  
Flow Conditions ◽  
Downstream Site ◽  
Upstream Site ◽  
The North ◽  
Main River

Abstract The identity and concentrations of chlorophenolic compounds in the Fraser River estuary were determined under conditions of high and low river flow at three sites: a site upstream from the trifurcation and at downstream sites for each main river arm. Major chlorophenolics present under both flow regimes were 2,4,6-trichlorophenol (2,4,6-TCP), 2,3,4,6-tetrachlorophenol (2,3,4,6-TeCP), pentachlorophenol (PCP), tetrachloroguaiacol (TeCG) and a compound tentatively identified as 3,4,5-trichloroguaiacol (3,4,5-TCG). Under high flow conditions, concentrations of the guaiacols were higher than any of the Chlorophenols and concentrations of all five chlorophenolics appeared to correlate. Under low flow conditions, concentrations of chloroguaiacols were higher than Chlorophenols at the upstream site and at the downstream site on the Main Arm, whereas at the downstream site on the North Arm, concentrations of 2,3,4,6-TeCP and PCP were higher than the chloroguaiacols in some samples. Overall, the results indicate that pulp mills upstream from the estuary are important sources of chlorophenolics to the estuary under all flow conditions. Additional episodic inputs of 2,3,4,6-TeCP and PCP from lumber mills occur along the North Arm. When these inputs occur, they can cause the concentrations of Chlorophenols in the North Arm to exceed provisional objectives. If chloroguaiacols are included as part of the objective, concentrations of total chlorophenolics in water entering the estuary can approach and exceed these objectives, especially under low flow conditions.

scholarly journals Calibration of hydrological models for ecologically relevant streamflow predictions: a trade-off between fitting well to data and estimating consistent parameter sets?

2020 ◽  
Vol 24 (3) ◽  
pp. 1031-1054 ◽  
Author(s):  
Thibault Hallouin ◽  
Michael Bruen ◽  
Fiachra E. O'Loughlin
Keyword(s):  
Flow Regime ◽  
River Flow ◽  
Freshwater Ecosystems ◽  
Living Environment ◽  
Rate Of Change ◽  
Low Flow ◽  
Hydrological Models ◽  
Flow Conditions ◽  
Local Flow ◽  
Trade Off

Abstract. The ecological integrity of freshwater ecosystems is intimately linked to natural fluctuations in the river flow regime. In catchments with little human-induced alterations of the flow regime (e.g. abstractions and regulations), existing hydrological models can be used to predict changes in the local flow regime to assess any changes in its rivers' living environment for endemic species. However, hydrological models are traditionally calibrated to give a good general fit to observed hydrographs, e.g. using criteria such as the Nash–Sutcliffe efficiency (NSE) or the Kling–Gupta efficiency (KGE). Much ecological research has shown that aquatic species respond to a range of specific characteristics of the hydrograph, including magnitude, frequency, duration, timing, and the rate of change of flow events. This study investigates the performance of specially developed and tailored criteria formed from combinations of those specific streamflow characteristics (SFCs) found to be ecologically relevant in previous ecohydrological studies. These are compared with the more traditional Kling–Gupta criterion for 33 Irish catchments. A split-sample test with a rolling window is applied to reduce the influence on the conclusions of differences between the calibration and evaluation periods. These tailored criteria are shown to be marginally better suited to predicting the targeted streamflow characteristics; however, traditional criteria are more robust and produce more consistent behavioural parameter sets, suggesting a trade-off between model performance and model parameter consistency when predicting specific streamflow characteristics. Analysis of the fitting to each of 165 streamflow characteristics revealed a general lack of versatility for criteria with a strong focus on low-flow conditions, especially in predicting high-flow conditions. On the other hand, the Kling–Gupta efficiency applied to the square root of flow values performs as well as two sets of tailored criteria across the 165 streamflow characteristics. These findings suggest that traditional composite criteria such as the Kling–Gupta efficiency may still be preferable over tailored criteria for the prediction of streamflow characteristics, when robustness and consistency are important.

River flow abstraction due to hydraulic storage at freezeup

2009 ◽  
Vol 36 (3) ◽  
pp. 519-523 ◽  
Author(s):  
Spyros Beltaos
Keyword(s):  
Water Quality ◽  
River Flow ◽  
Ice Cover ◽  
Low Flow ◽  
Flow Data ◽  
Flow Conditions ◽  
Ice Concentration ◽  
Cover Thickness ◽  
Water Quality And Quantity

A hydrologic extreme that can be partly generated by ice effects is low winter flow, which is known for potential impacts on water quality and quantity of rivers receiving effluent discharges or industrial withdrawals. Flow abstraction caused by hydraulic storage during the upstream propagation of an ice cover is quantified using the equations of continuity for ice and water. The flow abstraction is shown to increase with increasing ice concentration, but to decrease with increasing ice cover thickness. Numerical values are consistent with winter abstractions indicated by flow data from Canadian hydrometric stations. The present results further suggest that low-flow conditions in winter should generally improve, or at least not deteriorate, under a warmer climate.

Pollution in the Strait of Georgia: a Review

1983 ◽  
Vol 40 (7) ◽  
pp. 1142-1167 ◽  
Author(s):  
Michael Waldichuk
Keyword(s):  
Urban Communities ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
River Estuary ◽  
Oxygen Depletion ◽  
Fraser River ◽  
Pulp Mills ◽  
Strait Of Georgia ◽  
Spring Freshet

The Strait of Georgia, when considered as a whole, is still comparatively free of major pollution problems. Local environmental degradation has taken place, however, in waters on the periphery of the Strait, adjacent to urban communities and industries, such as pulp mills. The Fraser River, which is the major source of freshwater to the Strait, introduces natural and man-made materials that can adversely affect its estuary and the marine environment. The Strait of Georgia is flushed regularly, with deep waters being replaced about annually and waters in the upper layer having a considerably shorter residence time. Buildup of pollutants or their effects, e.g. oxygen depletion, are prevented in this way. However, there is refluxing of surface waters into the deep zone from the mixing region at the southern entrance to the Strait, and this means that surface pollutants such as oil could pollute the deep water and be retained there for up to a year. Problems affecting fisheries have been identified at the Fraser River Estuary arising from discharge of sewage treatment plant effluent. The major problem of pollution affecting fisheries in the Strait of Georgia has been bacteriological contamination from sewage, which has necessitated the closure of shellfish beds. The quality of oysters, as represented by condition factor and flavor, has deteriorated in the vicinity of some pulp mills. Evidence so far indicates that the "critical pollutants," e.g. petroleum hydrocarbons, organochlorines, and metals, which are persistent, toxic, and can be bioaccumulated by marine organisms, are present in low concentrations in the water, sediments, and biota away from the Fraser River Estuary. Wood wastes in the Strait of Georgia create a menace to navigation, especially during the spring freshet of the Fraser River.

Identifying resuspended sediment in an estuary using the 228Th/232Th activity ratio: the fate of lagoon sediment in the Bega River estuary, Australia

2000 ◽  
Vol 51 (7) ◽  
pp. 659 ◽  
Author(s):  
Gary J. Hancock
Keyword(s):  
Suspended Sediment ◽  
River Flow ◽  
Activity Ratio ◽  
Sediment Resuspension ◽  
River Estuary ◽  
Low Flow ◽  
Eastern Australia ◽  
Lagoon Sediment ◽  
Thorium Series ◽  
High River Flow

Thorium-series nuclides (228Th and 232Th) have been used to identify resuspended sediment in the Bega River estuary, south-eastern Australia. A non-conservative increase in concentration of suspended sediment of water in the vicinity of mid-estuary back-flow lagoons was associated with a decrease in the 228Th/232Th activity ratio (AR) of the suspended sediment. The lagoon sediment is characterized by a low estuarine 228Th/232Th signature, distinguishing it from freshwater suspended sediment recently delivered to the estuary, and identifying it as the likely source of the additional suspended sediment. Sediment-core 210Pb profiles show that the lagoons are accumulating sediment, presumably during high river-flow events. However this study indicates that during intervening periods of low flow, 40% of sediment deposited in the lagoons is subsequently resuspended and exported to the lower estuary, and possibly to the ocean. The utility of the 228Th/232Th AR to quantify sediment resuspension in estuaries is likely to be estuary-dependent, and is controlled by the extent of scavenging of dissolved 228Th by suspended particles.

Identity and Distribution of Chlorophenols in the North Arm of the Fraser River Estuary

1988 ◽  
Vol 23 (1) ◽  
pp. 31-44 ◽  
Author(s):  
J. H. Carey ◽  
M. E. Fox ◽  
J. H. Hart
Keyword(s):  
River Estuary ◽  
Fraser River ◽  
Regression Analyses ◽  
The North

Abstract Chlorophenol concentrations in fish and water from the North Arm of the Fraser River were determined. Geographical distributions and regression analyses indicated that 2,4-dichlorophenol, 2,3,5- and 2,4,6-trichlorophenol were correlated and likely entered the estuary from upstream sources whereas the source of 2,3,4,6-tetrachlorophenol and pentachlorophenol was likely lumber mills within the estuary. Concentrations of the latter two Chlorophenols in fish were from 100 to 14 00 times greater than in the water indicating the these compounds were bioconcentrating. Sculpins accumulated proportionately higher levels than other species and may be a good candidate biomonitor organism.

Uptake of Selected Organochlorine Contaminants in Fishes Resident in the Fraser River Estuary, Vancouver, British Columbia

1992 ◽  
Vol 27 (4) ◽  
pp. 733-750 ◽  
Author(s):  
I.H. Rogers ◽  
J.S. Macdonald ◽  
M. Sadar
Keyword(s):  
British Columbia ◽  
Food Chain ◽  
River Estuary ◽  
Control Fish ◽  
Fraser River ◽  
The North ◽  
Organochlorine Contaminants

Abstract Starry flounders, prickly sculpins and other resident fishes were captured in the Lower Fraser River in the summers of 1987, 1988 and 1989. Control fish were taken from the estuary of the uncontaminated Homathko River on the B.C. coast in 1987 and 1988. The fish were analysed for chlorophenols, chloroguaiacols and PCBs. The residues most commonly detected were PCBs, tetra-and pentachlorophenol. Fish from the Main Arm contained PCBs that resembled Arochlor 1248 whereas those from the North Arm contained PCBs that resembled a mixture of Arochlors 1254 and 1260. Chloroguaiacol uptake was greater in flounders than in other species. Although PCBs appear to have declined markedly in the Lower Fraser from values published in the early 1970s, there is a need to measure the coplanar fraction to understand their toxic significance to the food chain. Tetra- and pentachlorophenol have declined following a change by industry to the use of alternative sapstain prevention treatments.

Non-stationarity of low flows and their relevance to river modelling during drought periods

2017 ◽  
Vol 68 (12) ◽  
pp. 2306 ◽  
Author(s):  
David W. Rassam ◽  
Daniel Pagendam ◽  
Mat Gilfedder ◽  
Lu Zhang
Keyword(s):  
Regression Analysis ◽  
River Flow ◽  
Low Flow ◽  
Flow Conditions ◽  
Low Flows ◽  
River Modelling ◽  
Quantile Regression Analysis ◽  
River Models ◽  
Groundwater Contribution ◽  
Ltb Metric

Changes in groundwater storage lead to a reduction in groundwater contribution to river flow and present as non-stationarity, especially during low-flow conditions. Conventional river models typically ignore this non-stationarity, and, hence, their predictions of declines in low flows during drought periods are likely to be compromised. The present study assesses non-stationarity and highlights its implications for river modelling. A quantile regression analysis showed non-stationarity of low flows in the Namoi catchment (Australia), with statistically significant downward trends in the 10th percentile of log-transformed baseflow (10-LTB). This highlighted the usefulness of the 10-LTB metric to identify non-stationarity and, hence, alert modellers to the importance of adopting models that explicitly account for groundwater processes when modelling such river systems.

Characteristics of sediments in a newly constructed reservoir in Japan

2006 ◽  
Vol 53 (2) ◽  
pp. 73-78 ◽  
Author(s):  
Y. Sakurai ◽  
S. Haruta
Keyword(s):  
High Flow ◽  
Low Flow ◽  
Particulate Phosphorus ◽  
Formation Mechanisms ◽  
Flow Conditions ◽  
Discharge Rates ◽  
Main River ◽  
Sediment Formation ◽  
Specific Discharge ◽  
Land Surfaces

The sediment formation mechanisms of a newly constructed reservoir in Ehime, Japan were evaluated by characterizing the soil particles (SP) and particulate phosphorus (PP) in the runoff and reservoir sediments. The SP and PP loads from the runoffs of the main river in the watershed considerably increased, when the specific discharge rates were over 300 l/s/km2 (high flow conditions). When the specific discharge rates exceeded over 300 l/s/km2, 19% of the watershed generated over 80% of the SP and PP loads. When the specific discharge rates were under 300 l/s/km2 (low flow conditions), the contributions of the previously mentioned 19% area to the SP and PP loads were smaller. Significant amounts of smectite were found in the sediments in the reservoir and in the soil samples obtained at the forest exposed area in this 19% area while it was negligible in citrus orchards and paddy fields that constituted the remaining land surfaces. The forest area exposed by recent landslides was significant for the SP and PP in the reservoir. Judging from the outcomes, land use information alone may not be sufficient to detect critical sources of SP and PP in the runoffs and reservoirs. To identify and confirm crucial areas for the SP and PP in the runoffs, the investigations should be conducted under high flow conditions and the composition of clay minerals in the sediments should be checked against the clay mineral distributions of soils in the watershed.

scholarly journals Hydrodynamic Condition Modeling along the North-Central Coast of Vietnam

2020 ◽  
Vol 10 (3) ◽  
pp. 5648-5654
Author(s):  
D. D. Cham ◽  
N. T. Son ◽  
N. Q. Minh ◽  
N. T. Hung ◽  
N. Tien Thanh
Keyword(s):  
Sediment Transport ◽  
River Flow ◽  
Morphological Changes ◽  
Main Channel ◽  
Low Flow ◽  
Hydrodynamic Condition ◽  
Central Coast ◽  
North Central ◽  
The North ◽  
Coast Of Vietnam

An extremely dynamic morphology of the estuary is observed in the coastal regions of Vietnam under the governing processes of tides, waves, and river system flows. The primary target of this paper is to provide insight into the governing processes and morphological behavior of the NhatLe estuary, located in the north-central coast of Vietnam. Based on measured data from field surveys and satellite images combined with numerical model simulations of MIKE and Delft3D, the influences of seasonal river flow, tides, and wave dynamics on the sediment transport and morphological changes are fully examined. The study showed that freshwater flow in the flood season plays a central role in cutting off the southern sandspit, maintain and shaping the main channel. The prevailing waves in winter and summer induce longshore drift and sediment transport in the southeast to northwest direction. In the low flow season, this longshore sediment transport is dominant, causing sediment to deposit on the southern side of the ebb tidal delta and elongating the southern sandspit which narrows the estuary entrance and reorients the main channel.

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