Delineating a road-salt plume in lakebed sediments using electrical resistivity, piezometers, and seepage meters at Mirror Lake, New Hampshire, U.S.A

Geophysics ◽  
2010 ◽  
Vol 75 (4) ◽  
pp. WA75-WA83 ◽  
Author(s):  
Laura Toran ◽  
Melanie Johnson ◽  
Jonathan Nyquist ◽  
Donald Rosenberry

Electrical-resistivity surveys, seepage meter measurements, and drive-point piezometers have been used to characterize chloride-enriched groundwater in lakebed sediments of Mirror Lake, New Hampshire, U.S.A. A combination of bottom-cable and floating-cable electrical-resistivity surveys identified a conductive zone [Formula: see text] overlying resistive bedrock [Formula: see text] beneath the lake. Shallow pore-water samples from piezometers in lakebed sediments have chloride concentrations of [Formula: see text], and lake water has a chloride concentration of [Formula: see text]. The extent of the plume was estimated and mapped using resistivity and water-sample data. The plume ([Formula: see text] wide and at least [Formula: see text] thick) extends nearly the full length and width of a small inlet, overlying the top of a basin formed by the bedrock. It would not have been possible to mapthe plume’s shape without the resistivity surveys because wells provided only limited coverage. Seepage meters were installed approximately [Formula: see text] from the mouth of a small stream discharging at the head of the inlet in an area where the resistivity data indicated lake sediments are thin. These meters recorded in-seepage of chloride-enriched groundwater at rates similar to those observed closer to shore, which was unexpected because seepage usually declines away from shore. Although the concentration of road salt in the northeast inlet stream is declining, the plume map and seepage data indicate the groundwater contribution of road salt to the lake is not declining. The findings demonstrate the benefit of combining geophysical and hydrologic data to characterize discharge of a plume beneath Mirror Lake. The extent of the plume in groundwater beneath the lake and stream indicate there will likely be a long-term source of chloride to the lake from groundwater.

1978 ◽  
Vol 13 (1) ◽  
pp. 121-134 ◽  
Author(s):  
David Robert Lee ◽  
H.B.N. Hynes

Abstract Several new techniques were used to identify zones of groundwater and contaminant inflow to the headwaters area of a small stream draining an agricultural watershed in southwestern Ontario. Along a 3 km length of stream, seepage meters were used to measure and collect seepage flux and mini-piezometers were used to measure piezometric head relative to the stream and to collect pore water 0.6 m below the streambed. Measurement of seepage flux at 43 locations along a 3 km segment of Hillman Creek showed that most of the study section was a groundwater discharge zone. Spatial differences in seepage flux ranged from less than 0.001 to nearly 9 cm m s 1. During the growing season there was a marked diurnal change in seepage rate at several locations and this was also reflected by a corresponding change in stream discharge. Paired samples, one from a piezometer 0.6 m below streambed and one from the adjacent seepage meter, were significantly correlated (P < 0.01) with respect to specific conductance, chloride and inorganic carbon concentration. This suggested that in many instances site-specific estimates of chemical inputs from groundwater to surface water can be estimated quickly without the necessity of allowing natural groundwater flow to flush out the water initially trapped within the seepage container. Seepage meters can be used to measure seepage flux and the small piezometers can be used to obtain samples. The concentrations of non-conservative solutes (organic carbon, nitrate + nitrite nitrogen, and phospate) in seepage meter samples were not significantly correlated with the concentrations in corresponding mini-piezometer samples.


1988 ◽  
Author(s):  
Alex M. Sturrock ◽  
D.C. Buso ◽  
J.L. Scarborough ◽  
T.C. Winter

2010 ◽  
Vol 45 (4) ◽  
pp. 451-461 ◽  
Author(s):  
Nandana Perera ◽  
Bahram Gharabaghi ◽  
Peter Noehammer ◽  
Bruce Kilgour

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.


1984 ◽  
Vol 22 (1) ◽  
pp. 567-572 ◽  
Author(s):  
Robert E. Moeller ◽  
Frank Oldfield ◽  
Peter G. Appleby

1978 ◽  
Vol 56 (12) ◽  
pp. 1425-1433 ◽  
Author(s):  
Robert E. Moeller

The evergreen characteristic of Lobelia dortmanna L. involves biomass and nutrient conservation. Although 60% of the maximum, midsummer biomass overwinters, little or no new tissue is produced between October and early May. Annual net production, estimated from the rate of leaf turnover, is less than the maximum biomass (P/B = 0.69 per year). Nitrogen and P concentrations are lowest in mid-August, when the amount of each analyzed element per square metre is near its maximum (N, P, Ca, Mg, Na, K). Autumnal uptake of N may contribute 25% of the next season's growth requirements, but P uptake is largely offset by losses during the winter. Fruiting and sterile plants have similar contents of N, P, and K in late July, but the fruiting plants are richer in Ca, Mg, Na, Fe, Mn, and Zn. At the maximum depth limit of the population in Mirror Lake, New Hampshire (2.3 m), flowering is absent and seedlings are sparse, suggesting reproductive failure as a controlling factor at the margin of the population.


1989 ◽  
Vol 26 (11) ◽  
pp. 2186-2193 ◽  
Author(s):  
Jacques Locat ◽  
Pierre Gélinas

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.


Author(s):  
Venkatesan B ◽  
Kannan V ◽  
Sophia M

This paper aims to assess the mechanical and long-term durability performance of Reactive Powder Concrete (RPC) containing Granite Powder (GrP) as cement replacement and waste Glass Powder (GP) as quartz sand replacement. The workability and mechanical behaviour of RPC containing various proportions of GrP and GP are assessed for different w/b ratios (0.3, 0.35, 0.4 and 0.45). The water resistance and tightness of RPC are measured by monitoring the electrical resistivity, water absorption, sorptivity and chloride migration over a one year period. Results reveal that substitution of GrP and GP at optimum levels of 15% and 30% respectively enhances the performance of RPC with the achievement of satisfiable workability at a 0.35 w/b ratio. A significant increase in the resistance towards chloride penetration and electrical resistivity was also observed with increasing ages. Thus, glass powder and granite powder can be considered as alternative construction materials providing economical and ecological efficiency.


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