Geology topics

J. B. Shanley

Publications and source records attributed to J. B. Shanley.

25 records · Page 2Linked to original sources

USGS1995

Effects of selective forest clearing fertilization, and liming on the hydrology and water quality of a small tributary to the Quabbin Reservoir, central Massachusetts

Effects of selective forest clearing on water yield and water quality were investigated in a 308-hectare basin that drains to Quabbin Reservoir Watershed in central Massachusetts. The experimental basin and a nearby 280-hectare control basin were studied together for comparison. Streamflow was measured continuously and water-quality samples were collected biweekly in both basins from February 1985 through September 1989. During the same period, measurements of precipitation quantity and ground- water levels were made and samples were collected for determination of precipitation and ground-water quality. After an initial monitoring period to establish baseline hydrology and water quality in both basins, an area of red pine and white pine forest in the experimental basin was cleared. From October 1986 until April 1987, 23.8 percent of the total basal area was removed by clearcutting and thinning. Part of the cleared area was converted to rye and other field grasses, and the remainder was allowed to regrow naturally. Fertilizer and lime were applied to part of the cleared area. An additional 8.3 percent of basal area was cleared in fall 1988. Despite differences in bedrock geology, topography, and amount of wetland area, pre- treatment hydrology and chemistry of the two basins were similar. Biogeochemical reactions of the dilute mixture of sulfuric and nitric acids in precipitation with soils and rocks in the basins resulted in moderately buffered calcium-magnesium bicarbonate-type streamwater. During high flows, sulfate concentrations increased and alkalinity decreased. Selective forest clearing resulted in a slight increase in water yield during the year in which the clearing took place, particularly during the spring high-flow period, but flows returned to normal thereafter. Concurrent increases in solute flux were primarily a function of the increased water flux. No major alterations to biogeochemical processes were induced by the forest clearing, nor were any effects from the fertilizer or liming activity observed. The minimal effect observed from the clearing was attributed primarily to the limited area that was cleared, and the location of the cleared area in the headwaters of the basin (away from the riparian zone).

Massachusetts↗

USGS1995

Chemical and isotopic evolution of a layered eastern U.S. snowpack and its relation to stream-water composition

The chemical, isotopic, and morphologic evolution of a layered snowpack was investigated during the winter of 1993-94 at Sleepers River Research Watershed in Danville, Vermont. The snowpack was monitored at two small basins: a forested basin at 525 m elevation, and an agricultural basin at 292 m elevation. At each site, the snowpack morphology was characterized and individual layers were sampled seven times during the season. Nitrate and 8d18O profiles in the snowpack remained relatively stable until peak accumulation in mid-March, except near the snow surface, where rain-on-snow events caused water and nitrate movement down to impeding ice layers. Subsequently, water and nitrate moved more readily through the ripening snowpack. As the snowpack evolved, combined processes of preferential ion elution, isotopic fractionation, and infiltration of isotopically heavy rainfall caused the pack to become depleted in solutes and isotopically enriched. The release of nitrate and isotopically depleted water was reflected in patterns of nitrate concentrations and ??18O of meltwater and stream water. Results supported data from the previous year which suggested that streamflow in the forested basin during snowmelt was dominated by groundwater discharge.

Biogeochemistry of seasonally snow-covered catchme↗

USGS1994

Effects of ion exchange on stream solute fluxes in a basin receiving highway deicing salts

At Fever Brook, a 1260-ha forested basin in central Massachusetts, highway deicing salt application increased the solute flux in streamflow by 120% above background flux (equivalent basis) during a 2-yr period. Attempts to isolate the nonsalt component of stream solute fluxes have commonly subtracted salt contributions based on the net Cl flux (Cl output in streamflow minus Cl input in precipitation). In these studies, any net Na flux in excess of the amount needed to balance the net Cl flux has been attributed to weathering. At Fever Brook, however, the net output of Na was less than the net output of Cl, suggesting a loss of Na within the basin. The Na sink was inferred to be cation exchange of Na for Ca and Mg in the soil. A method was developed to quantify the exchange based on a Na budget, which included an independent estimate of the Na flux from weathering. The amount of exchange was apportioned to Ca and Mg based on their relative concentrations in the stream. The background fluxes of Ca and Mg (i.e., those that would occur in the absence of deicing salts) were calculated by subtracting the amounts from ion exchange plus the much smaller direct contributions in deicing salts from the observed fluxes. Ion exchange and direct salt contributions increased the net output fluxes of Ca and Mg, each by 44% above background. In basins that receive deicing salts, failure to account for cation exchange thus may result in an underestimate of the flux of Na from weathering and overestimates of the fluxes of Ca and Mg from weathering.

Journal of Environmental Quality↗

USGS1994

Effects of storm paths on precipitation chemistry, and variations of within-storm chemistry during selected storms in central Massachusetts, 1986-87

Samples of precipitation from 31 storms were collected from October 1986 through December 1987 at a site near Quabbin Reservoir in central Massachusetts and were analyzed for pH, specific conductance, and concentrations of common chemical constituent. Twenty-four storms followed a conti- nental path west of the Appalachian Mountains. The remaining seven storms followed a coastal path east of the Appalachian Mountains along the Atlantic Coast. Precipitation from the continental storms was more acidic than precipitation from the coastal storms according to a nonparametric statistical com- parison. Because the continental storms had less volume, the loads of hydrogen ions and other common chemical constituents from both groups were not statistically different. The variability of within- storm precipitation chemistry was evaluated for 8 of the 31 storms. Seven of the storms showed evidence of suspended-particulate removal at levels between the cloud layer and the land surface during their early stages. The remaining storm, also the most acidic, showed evidence of suspended- particulate removal within the cloud layer as indicated by a relatively constant pH throughout the storm. Surface-air concentrations of sulfur dioxide and nitrogen dioxide before, during, and after each of the eight storms were compared to within-storm values of pH and precipitation. Seven of the storms were accompanied by decreased atmospheric concen- trations of both sulfur dioxide and nitrogen dioxide in the early stages of the storm. For three of the storms, atmospheric concentrations of sulfur dioxide and nitrogen dioxide were higher during the 24-hour period after the storm than the 24-hour period pre- ceding the storm. Particulates in precipitation samples were analyzed for three storms. Biotite was the predominant mineral in two of the storms. Other minerals detected were garnet, quartz, gypsum, hematite, epidote, ilmenite, eggonite, halite, rutile, and organic ash.

Water-Resources Investigations Report↗

USGS1993

Variations in aqueous sulfate concentrations at Panola Mountain, Georgia

Aqueous sulfate concentrations were measured in incident precipitation, canopy throughfall, stemflow, soil water, groundwater, and streamwater at three locations in a 41 ha forested watershed at Panola Mountain State Park in the Georgia Piedmont. To evaluate the variations in sulfate concentrations, sampling intensity was increased during storms by automated collection of surface water and by incremental subsampling of rainfall, throughfall, and soil solution. Canopy throughfall, stemflow, and runoff from a bedrock outcrop in the watershed headwaters were enriched in sulfate relative to incident precipitation due to washoff of dry deposition that accumulated between storms. Soil waters collected from zero-tension lysimeters at 15 cm and 50 cm below land surface also were enriched in sulfate relative to precipitation, groundwater and streamwater. Sulfate concentrations in groundwater and in streamwater at base flow varied in an annual sinusoidal pattern with winter maxima and summer minima. Stream discharge and groundwater levels varied in a similar annual pattern in phase with the sulfate concentrations. The temporal variability of sulfate concentrations at most groundwater sites was small relative to the spatial variability among groundwater sites. Streamwater sulfate concentrations during base flow were controlled by low-sulfate groundwater discharge. As flow increased, an increasing proportion of shallow, high-sulfate groundwater and soil water contributed to streamflow. The dominant control on stream sulfate concentration shifted from sulfate retention by adsorption in the mineral soil at base flow to mobilization of sulfate from the upper, organic-rich horizons of the soil at high flow.

Journal of Hydrology↗

USGS1989

Field measurements of dry deposition to spruce foliage and petri dishes in the Black Forest, F.R.G.

Dry deposition fluxes of Ca 2+ , Mg 2+ , K + , Mn 2+ , Pb 2+ and SO 2− 4 to spruce foliage and petri dishes were measured in two high-elevation sites ( > 900 m) in the southern Black Forest, F.R.G., during 12 periods (2–7 days, each) from mid-September to mid-November, 1983, In situ extraction of deposited material from small spruce branches allowed repeated use of the same foliar collecting surfaces for a direct comparison of deposition between periods. Fluxes were corrected for leaching of internally cycled constituents using factors determined from serial extraction experiments. The ratio of flux to petri dishes vs foliage ( P F "> PF ) was > 1.0 for Ca 2+ , Pb 2+ and SO 2− 4 , and somewhat < 1.0 but more constant for Mg 2+ . Temporal variations in dry deposition fluxes at an exposed site near the industrialized Rhine Valley correlated with variations in total air particulate concentrations at a nearby air quality station. Deposition rates were comparable in magnitude but different in temporal pattern at a remote site in the Black Forest interior. Fluxes at each site reached a minimum during the period of 4–9 November when a regional air inversion confined pollutants to the Rhine Valley below the study sites. High fluxes accompanied the inversion break-up.

Black Forest↗

USGS1988

Preliminary observations of streamflow generation during storms in a forested Piedmont watershed using temperature as a tracer

Variations in streamwater temperature at the outlet of a 41-ha forested watershed at Panola Mountain in the Georgia Piedmont indicate that the initial rapid hydrologic response is caused by a combination of groundwater discharge and channel interception of rainwater. A storm in May 1986 caused a rapid increase in discharge that was accompanied by a decrease in streamwater temperature and a rise in the water table level adjacent to the stream. The higher water table provided the hydraulic gradient necessary to increase the discharge of colder groundwater to the stream. Storms that occurred under very dry antecedent conditions in July 1986 and June 1987 caused a rapid hydrologic response but no change in water table level, indicating the response was caused by channel interception of rainwater. This conclusion was supported by increases in streamwater temperature in the June storm and by chemical changes in the July storm. When rainfall is sufficient, flow in the ephemeral part of the stream in the catchment headwaters generates a second and larger discharge peak that reflects the chemistry and temperature of runoff from a 3-ha granite outcrop in the headwaters; sulfate concentration and temperature increase and alkalinity decreases relative to prestorm conditions. The initial response, however, results from channel interception and groundwater discharge. Rapid rises in the water table level during some storms suggest that macropore flow may play a major role in the hydrologic response of the watershed to rainstorms.

Journal of Contaminant Hydrology↗