Road Salt Application in Highland Creek Watershed, Toronto, Ontario - Chloride Mass Balance

2010 ◽  
Vol 45 (4) ◽  
pp. 451-461 ◽  
Author(s):  
Nandana Perera ◽  
Bahram Gharabaghi ◽  
Peter Noehammer ◽  
Bruce Kilgour
Keyword(s):  
Mass Balance ◽  
Management Practices ◽  
Chloride Concentration ◽  
Aquatic Organisms ◽  
Terrestrial Ecosystems ◽  
Road Salt ◽  
Winter Period ◽  
Chloride Mass Balance ◽  
Creek Watershed ◽  
Chloride Concentrations

Abstract Occurrence of increasing chloride concentrations in urban streams of cold climates, mainly due to road salt application, has raised concerns on its adverse effects on aquatic and terrestrial ecosystems. Therefore, there is a need for a better understanding of processes associated with road salt application and subsequent discharge into the environment in order to develop management practices to minimize detrimental effects of chlorides. The chloride mass analysis for the Highland Creek watershed based on four years of hourly monitoring data indicates that approximately 60% of the chlorides applied on the watershed enter streams prior to subsequent salting period, 85% of which occurs during the period between November and March. Contribution of private de-icing operations on chloride mass input within Highland Creek watershed was estimated to be approximately 38%, indicating its significance in overall chloride mass balance. Salt application rates, as well as chloride output in the streams, vary spatially based on land use, influencing chloride concentrations in surface waters. The estimated groundwater chloride concentration of 275 mg/L indicates that some aquatic organisms in Highland Creek would potentially be at risk even outside the winter period under dry weather flow conditions.

scholarly journals Catchment conceptualisation for examining applicability of chloride mass balance method in an area with historical forest clearance

2010 ◽  
Vol 14 (7) ◽  
pp. 1233-1245 ◽  
Author(s):  
H. Guan ◽  
A. J. Love ◽  
C. T. Simmons ◽  
J. Hutson ◽  
Z. Ding
Keyword(s):  
Mass Balance ◽  
Groundwater Recharge ◽  
Chloride Concentration ◽  
Water Transfer ◽  
Annual Precipitation ◽  
Chloride Mass Balance ◽  
Balance Condition ◽  
Forest Clearance ◽  
Type V ◽  
Historical Forest

Abstract. Of the various approaches for estimating groundwater recharge, the chloride mass balance (CMB) method is one of the most frequently used, especially for arid and semiarid regions. Widespread native vegetation clearance, common in many areas globally, has changed the land surface boundary condition, posing the question as to whether the current system has reached new chloride equilibrium, required for a CMB application. Although a one-dimensional CMB can be applied at a point where the water and chloride fluxes are locally in steady state, the CMB method is usually applied at a catchment scale owing to significant lateral flows in mountains. The applicability of the CMB method to several conceptual catchment types of various chloride equilibrium conditions is examined. The conceptualisation, combined with some local climate conditions, is shown to be useful in assessing whether or not a catchment has reached new chloride equilibrium. The six conceptual catchment types are tested with eleven selected catchments in the Mount Lofty Ranges (MLR), a coastal hilly area in South Australia having experienced widespread historical forest clearance. The results show that six of the eleven catchments match a type VI chloride balance condition (chloride non-equilibrium with a gaining stream), with the ratios of stream chloride output (O) over atmospheric chloride input (I), or catchment chloride O/I ratios, ranging from 2 to 4. Two catchments match a type V chloride balance condition (chloride non-equilibrium with a losing stream), with catchment chloride O/I ratios about 0.5. For these type V and type VI catchments, the CMB method is not applicable. The results also suggest that neither a chloride O/I ratio less than one nor a low seasonal fluctuation of streamflow chloride concentration (a factor below 4) guarantees a chloride equilibrium condition in the study area. A large chloride O/I value (above one) and a large fluctuation of streamflow chloride concentration (a factor of 10 and above) generally indicates either a chloride disequilibrium, or cross-catchment water transfer, or both, for which the CMB method is not applicable. Based on regression between chloride O/I values and annual precipitation for type VI catchments, a catchment with annual precipitation of 900 mm in MLR has most likely reached new chloride equilibrium, and the CMB method can be applied if no cross-catchment water transfer occurs. CMB is applied to one catchment at chloride equilibrium, suggesting a net groundwater recharge of 27 mm/yr, about 3% of annual precipitation.

Anion exclusion effects on estimates of soil chloride and deep percolation

Soil Research ◽  
1993 ◽  
Vol 31 (4) ◽  
pp. 455 ◽  
Author(s):  
PG Slavich ◽  
GH Petterson
Keyword(s):  
Mass Balance ◽  
Soil Water ◽  
Electrolyte Concentration ◽  
Chloride Concentration ◽  
Deep Percolation ◽  
Chloride Mass Balance ◽  
Water Extracts ◽  
Mass Balance Models ◽  
Anion Exclusion ◽  
Soil Chloride

Anion exclusion affects estimates of deep percolation determined using chloride mass balance models. This paper evaluates potential errors arising from ignoring anion exclusion in both soil analysis methods and model assumptions. Soil chloride analysis from saturated paste and 1:5 soil/water extracts are compared with that of field soil water extracted using a filter paper technique. The influence of anion exclusion on estimates of soil water chloride concentration (Clsw mmol/L) and chloride content per unit mass of soil (CIT mmol/kg soil), both which are required by chloride mass balance models, is examined for these methods. The relative importance of total electrolyte concentration and sodium absorption ratio (SAR) on the anion exclusion volume of a clay was also determined using a simple laboratory leaching technique. The chloride concentration of soil water at field moisture contents was more closely related to estimates calculated from saturated paste extracts than from 1:5 soil/water extracts. Although the amount of excluded water estimated in the saturated paste was larger than that estimated at the field water content, the proportion of non-excluded water in each was similar. The ClT was overestimated when analysis from saturation extracts was used. Electrolyte concentration and SAR were shown to have similar (but opposite) relative effects on the exclusion volume. However, because these variables were positively correlated, their effects were not apparent in the field samples. For the clay soil under study, deep percolation could be overestimated by up to 1.64 times if anion exclusion effects were ignored when using 1:5 extracts to estimate Clsw. The errors were considerably less if saturation extracts were used to estimate Clsw and ClT.

scholarly journals Positive feedback of elevated CO<sub>2</sub> on soil respiration in late autumn and winter

2014 ◽  
Vol 11 (6) ◽  
pp. 8749-8787 ◽  
Author(s):  
L. Keidel ◽  
C. Kammann ◽  
L. Grünhage ◽  
G. Moser ◽  
C. Müller
Keyword(s):  
Soil Respiration ◽  
Elevated Co2 ◽  
Management Practices ◽  
Co2 Enrichment ◽  
Terrestrial Ecosystems ◽  
Winter Period ◽  
Elevated Atmospheric Co2 ◽  
Late Autumn ◽  
Below Ground ◽  
Autumn And Winter

Abstract. Soil respiration of terrestrial ecosystems, a major component in the global carbon cycle is affected by elevated atmospheric CO2 concentrations. However, seasonal differences of feedback effects of elevated CO2 have rarely been studied. At the Giessen Free-Air CO2 Enrichment (GiFACE) site, the effects of +20% above ambient CO2 concentration (corresponds to conditions reached 2035–2045) have been investigated since 1998 in a temperate grassland ecosystem. We defined five distinct annual periods, with respect to management practices and phenological cycles. For a period of three years (2008–2010), weekly measurements of soil respiration were carried out with a survey chamber on vegetation-free subplots. The results revealed a pronounced and repeated increase of soil respiration during late autumn and winter dormancy. Increased CO2 losses during the autumn period (September–October) were 15.7% higher and during the winter period (November–March) were 17.4% higher compared to respiration from control plots. However, during spring time and summer, which are characterized by strong above- and below-ground plant growth, no significant change in soil respiration was observed at the FACE site under elevated CO2. This suggests (i) that soil respiration measurements, carried out only during the vegetative growth period under elevated CO2 may underestimate the true soil-respiratory CO2 loss (i.e. overestimate the C sequestered) and (ii) that additional C assimilated by plants during the growing period and transferred below-ground will quickly be lost via enhanced heterotrophic respiration outside the main vegetation period.

scholarly journals Catchment conceptualisation for examining applicability of chloride mass balance method in an area of historical forest clearance

2009 ◽  
Vol 6 (6) ◽  
pp. 7025-7053 ◽  
Author(s):  
H. Guan ◽  
A. Love ◽  
C. T. Simmons ◽  
Z. Ding ◽  
J. Hutson
Keyword(s):  
Mass Balance ◽  
Groundwater Recharge ◽  
Chloride Concentration ◽  
Water Transfer ◽  
Annual Precipitation ◽  
Chloride Mass Balance ◽  
Balance Condition ◽  
Forest Clearance ◽  
Match Type ◽  
Non Equilibrium

Abstract. Among various approaches for estimating groundwater recharge, chloride mass balance (CMB) method is one of the most frequently used, in particular, for arid and semiarid regions. Widespread native vegetation clearance, common history in many areas globally, has changed land surface boundary condition, posing a question whether the current system has reached new chloride equilibrium for CMB application. To examine CMB applicability for catchments, conceptual catchment types of various chloride equilibrium conditions are defined. The conceptualization, combined with some local climate conditions, is demonstrated to be useful in examining whether a catchment has reached new chloride equilibrium. The six conceptual catchment types are tested with eleven selected catchments in the Mount Lofty Ranges (MLR), a coastal hilly area in South Australia having experienced historical widespread forest clearance. The results show that six of the eleven catchments match type VI chloride balance condition (chloride non-equilibrium with a gaining stream), with the ratio of stream chloride output over atmospheric chloride input (catchment chloride O/I) ranging from 2 to 4. Two catchments match type V chloride balance condition (chloride non-equilibrium with a losing stream), with catchment chloride O/I values about 0.5. For these catchments, the CMB method is not appropriate to apply. The results also suggest that neither a below-one chloride O/I value nor a low seasonal fluctuation of streamflow chloride concentration (a factor below 4) guarantees a chloride equilibrium condition in the study area. But a large chloride O/I value (above one) and a large fluctuation of streamflow chloride concentration (a factor of 10 and above) generally indicates either a chloride disequilibrium, or cross-catchment water transfer, or both, for which CMB is not applicable. Based on the regression between chloride O/I values and annual precipitation for type VI catchments, a catchment with annual precipitation of 900 mm in MLR has most likely reached new chloride equilibrium, for which CMB can be applied given that no cross-catchment water transfer occurs. CMB is applied for one catchment at chloride equilibrium, resulted in a net groundwater recharge estimate of 30 mm, about 4% of annual precipitation.

Field Measurements and Simulation of Nitrogen Fate under Citrus Production

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 498c-498
Author(s):  
A. Fares ◽  
A.K. Alva ◽  
S. Paramasivam
Keyword(s):  
Mass Balance ◽  
Best Management Practices ◽  
Rainy Season ◽  
Crop Production ◽  
Management Practices ◽  
Root Zone ◽  
Field Measurements ◽  
Irrigation Scheduling ◽  
N Leaching ◽  
Citrus Production

Water and nitrogen (N) are important inputs for most crop production. The main objectives of nitrogen best management practices (NBMP) are to improve N and water management to maximize the uptake efficiency and minimize the leaching losses. This require a complete understanding of fate of N and water mass balance within and below the root zone of the crop in question. The fate of nitrogen applied for citrus production in sandy soils (>95% sand) was simulated using a mathematical model LEACHM (Leaching Estimation And Chemistry Model). Nitrogen removal in harvested fruits and storage in the tree accounted the major portion of the applied N. Nitrogen volatilization mainly as ammonia and N leaching below the root zone were the next two major components of the N mass balance. A proper irrigation scheduling based on continuous monitoring of the soil water content in the rooting was used as a part of the NBMP. More than 50% of the total annual leached water below the root zone was predicted to occur in the the rainy season. Since this would contribute to nitrate leaching, it is recomended to avoid N application during the rainy season.

Pesticide Contamination of Groundwater in Virginia: BMP Impact Assessment

1993 ◽  
Vol 28 (3-5) ◽  
pp. 379-387 ◽  
Author(s):  
S. Mostaghimi ◽  
P. W. McClellan ◽  
R. A. Cooke
Keyword(s):  
Water Quality ◽  
Land Use ◽  
Best Management Practices ◽  
Water Samples ◽  
Management Practices ◽  
Water Quality Monitoring ◽  
Pesticide Contamination ◽  
Cropping Patterns ◽  
Creek Watershed ◽  
Surface And Groundwater

The Nomini Creek Watershed/Water Quality monitoring project was initiated in 1985, as part of the Chesapeake Bay Agreement of 1983, to quantify the impacts of agricultural best management practices (BMPs) on improving water quality. The watershed monitoring system was designed to provide a comprehensive assessment of the quality of surface and groundwater as influenced by changes in land use, agronomic, and cultural practices in the watershed over the duration of the project. The primary chemical characteristics monitored include both soluble and sediment-bound nutrients and pesticides in surface and groundwater. Water samples from 8 monitoring wells located in agricultural areas in the watershed were analyzed for 22 pesticides. A total of 20 pesticides have been detected in water samples collected. Atrazine is the most frequently detected pesticide. Detected concentrations of atrazine ranged from 0.03 - 25.56 ppb and occurred in about 26 percent of the samples. Other pesticides were detected at frequencies ranging from 1.6 to 14.2 percent of all samples collected and concentrations between 0.01 and 41.89 ppb. The observed concentrations and spatial distributions of pesticide contamination of groundwater are compared to land use and cropping patterns. Results indicate that BMPs are quite effective in reducing pesticide concentrations in groundwater.

A storm water retrofit plan for the mimico creek watershed

1999 ◽  
Vol 39 (12) ◽  
pp. 133-140
Author(s):  
J. Y. Li ◽  
D. Banting
Keyword(s):  
Water Quality ◽  
Quality Management ◽  
Great Lakes ◽  
Management Practices ◽  
Water Quality Management ◽  
Storm Water ◽  
Planning Tool ◽  
Creek Watershed ◽  
Urbanized Areas ◽  
Goals And Objectives

Storm water quality management in urbanized areas remains a challenge to Canadian municipalities as the funding and planning mechanisms are not well defined. In order to provide assistance to urbanized municipalities in the Great Lakes areas, the Great Lakes 2000 Cleanup Fund and the Ontario Ministry of the Environment commissioned the authors to develop a Geographic Information System planning tool for storm water quality management in urbanized areas. The planning tool comprises five steps: (1) definition of storm water retrofit goals and objectives; (2) identification of appropriate retrofit storm water management practices; (3) formulation of storm water retrofit strategies; (4) evaluation of strategies with respect to retrofit goals and objectives; and (5) selection of storm water retrofit strategies. A case study of the fully urbanized Mimico Creek wateshed in the City of Toronto is used to demonstrate the application of the planning tool.

Infiltration of de-icing road salts in aquifers: the Trois-Rivières-Ouest case, Quebec, Canada

1989 ◽  
Vol 26 (11) ◽  
pp. 2186-2193 ◽  
Author(s):  
Jacques Locat ◽  
Pierre Gélinas
Keyword(s):  
Unsaturated Zone ◽  
Chloride Concentration ◽  
Late Summer ◽  
Linear Source ◽  
Pumping Wells ◽  
Road Salts ◽  
Hydrogeological Investigation ◽  
Spring Snowmelt ◽  
Chloride Concentrations

The results of an extensive hydrogeological investigation of the effects of de-icing road salts on Highway 55 near Trois-Rivières-Ouest indicate that a salt lens with chloride concentrations exceeding 800 mg/L exists below the highway. Maximum chloride concentration at the nearby pumping wells, not exceeding 140 mg/L, is reached only in late summer, whereas the maximum chloride infiltration follows the spring snowmelt. About 1 year's worth of road salts is retained in the unsaturated zone. The salt lens, in the upper part of the aquifer beneath the highway, has developed to a thickness of 8 m and a width of 400 m and constitutes a linear source of salts for the aquifer. The shape of this lens is distorted by the action of the pumping wells, and the lens is partly depleted by the end of the summer. Because of the particular characteristics of the aquifer at the site studied and the exploitation methods, no long-term threat to the water quality is foreseen.

Column Study on the Effect of Nitrate and Chloride on TCE Removal by Granular Iron

2011 ◽  
Vol 356-360 ◽  
pp. 1642-1646
Author(s):  
Xue Qiang Zhu ◽  
Bao Ping Han ◽  
Guo Jun Wu ◽  
Xiao Qing Zhang
Keyword(s):  
Pitting Corrosion ◽  
Nitrate Concentration ◽  
Chloride Concentration ◽  
Inorganic Anions ◽  
Dual Effect ◽  
Column Study ◽  
Granular Iron ◽  
High Chloride ◽  
Chloride Concentrations

The effects of individual inorganic anions (nitrate and chloride) on the reactivity of granular iron were investigated using plexiglass columns packed with granular iron. The results show that TCE removal decreases apparently with increasing nitrate concentration due to competition for reactive sites. Chloride exhibits dual-effect on the TCE removal by Fe0. In the studied condition, the TCE dechlorination is enhanced at the low chloride concentration due to pitting corrosion and is dampened at the high chloride concentrations such as 59.98 and 110.45 mg/L as Cl-.

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