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  • 1
    Electronic Resource
    Electronic Resource
    STREAM CHEMISTRY IN THE SOUTHERN BLUE RIDGE: FEASIBILITY OF A REGIONAL SYNOPTIC SAMPLING APPROACH (1988)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of the American Water Resources Association 24 (1988), S. 0 
    Details
    ISSN: 1752-1688
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Geography
    Notes: : A pilot study, which was conducted in the Southern Blue Ridge geographical province of the Southeastern U.S., demonstrated the feasibility of a probability-based regional synoptic design for the National Stream Survey, which is a project aimed at estimating the number and percentage of streams in various regions of the U.S. that are acidic or at risk from acid deposition. Estimated population distributions for key chemical variables were not appreciably affected by week-to-week variability in stream chemistry during the spring index period chosen for the study. Differences were observed in estimated acid neutralizing capacity (ANC), nitrate, and pH frequency distributions between spring and summer. Observations made at the downstream node did not represent the chemistry of the entire reach for some variables (ANC and nitrate) as indicated by differences in chemical concentrations between upstream and downstream sampling locations. Coefficients of variation in chemical species were low enough to provide a reasonably stable classification of streams based on ANC. Although median ANC, sulfate, and nitrate concentrations were quite low in the region, the probability of finding streams with ph 〈 6.3 is less than 1.3 percent at the α= 0.05 confidence level.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1752-1688.1988.tb00933.x
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  • 2
    Electronic Resource
    Electronic Resource
    Assessing the regional effects of sulfur deposition on surface water chemistry: the Southern Blue Ridge (1988)
    s.l. : American Chemical Society
    Environmental science & technology 22 (1988), S. 685-690 
    Details
    ISSN: 1520-5851
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/es00171a011
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  • 3
    Electronic Resource
    Electronic Resource
    The influence of substrate quality and stream size on wood decomposition dynamics (1983)
    Springer
    Oecologia 58 (1983), S. 281-285 
    Details
    ISSN: 1432-1939
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Woody materials decayed more rapidly in a first order stream than in larger streams in eastern Quebec, Canada. The rate of annual mass loss (k) was highest (k=1.20) for alder wood chips in a first order stream and lowest (k=0.04) for black spruce wood chips in a ninth order stream. Decay rates for woody materials in a first order stream were inversely related to their initial lignin to nitrogen ratios. In larger streams, decay rates of woody materials were inversely related to their initial lignin concentrations. A number of quantifiable relationships were found to exist between the initial lignin and nitrogen contents of woody materials and the nitrogen dynamics of decaying wood.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00385224
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  • 4
    Electronic Resource
    Electronic Resource
    Episodic acidification of freshwater systems in Canada — Physical and geochemical processes (1994)
    Springer
    Water, air & soil pollution 72 (1994), S. 19-39 
    Details
    ISSN: 1573-2932
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract The occurrence of episodic acidification in Canadian streams, lake waters and shallow groundwaters has been reviewed, and the contolling mechanisms identified. ‘Episodes’, which are periods of depressed alkalinity during hydrological events, have been studied mainly in southeastern Canada, and occur at all sites where there is sufficient time resolution of the observations, viz. Ontario, Quebec and Nova Scotia. An ‘alkaline episode’, where acidity decreases during an event, has been reported from one lake in the Canadian Artic. There is a bias towards the examination of episodes stimulated by snowmelt or rain-on-snow, since rainfall-stimulated episodes are poorly documented. Pre-event, rather than event, water dominates runoff during episodes. For this reason, biogeochemical reactions and the hydrological flowpaths in operation through the vadose and saturated zones are the principal controls on the chemical characteristics of episodes. Most episodes are dominated by base cation ‘dilution’ in circumneutral systems, and ‘increase in strong acid anions’ (particularly sulphate) in acidic systems. Episodes dominated by nitrification or organic acids or stimulated by sea salt input are rare or have not been decumented. Direct input of event water may dominate only during particular circumstances at snowmelt. Then, direct chemical inputs from lake ice and lake snow cover may be of importance in some systems.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01257115
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  • 5
    Electronic Resource
    Electronic Resource
    Potential future effects of current levels of sulfur deposition on stream chemistry in the southern blue ridge mountains, U.S. (1990)
    Springer
    Water, air & soil pollution 50 (1990), S. 39-48 
    Details
    ISSN: 1573-2932
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Using newly available regional data sets we examine the potential for future changes in stream acid neutralizing capacity (ANC) for the Southern Blue Ridge Province (SBRP) of the U.S. as related to (1) levels of S deposition, (2) retention of S within watersheds, (3) current surface water SO4, and (4) potential historical changes in surface water chemistry. We conclude that, although (1) little change in surface water chemistry (as affected by acidic deposition) likely has occurred in the region to date, and (2) soils are currently retaining a majority of atmospherically deposited S, it is likely that marked increases in surface water SO4 will occur. Such increases could be accompanied by significant surface water acidification (loss of ANC).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00284782
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  • 6
    Electronic Resource
    Electronic Resource
    Episodic acidification of a coastal plain stream in Virginia (1996)
    Springer
    Water, air & soil pollution 89 (1996), S. 291-316 
    Details
    ISSN: 1573-2932
    Keywords: episodic acidification
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract This study investigates the episodic acidification of Reedy Creek, a wetland-influenced coastal plain stream near Richmond, Virginia. Primary objectives of the study were to quantify the episodic variability of acid-base chemistry in Reedy Creek, to examine the seasonal variability in episodic response and to explain the hydrological and geochemical factors that contribute to episodic acidification. Chemical response was similar in each of the seven storms examined, however, the ranges in concentrations observed were commonly greater in summer/fall storms than in winter/spring storms. An increase in SO inf4 sup2− concentration with discharge was observed during all storms and peak concentration occurred at or near peak flow. Small increases in Mg2+, Ca2+, K+ concentrations and dissolved organic carbon (DOC) were observed during most storms. At the same time, ANC, Na+ and Cl− concentrations usually decreased with increasing discharge. In summer/fall storms, the absolute increase in SO inf4 sup2− concentration was one-third to 15 times the increase observed in winter/spring storms; the decrease in ANC during summer/fall storms was usually within the range of the decrease observed in winter/spring storms. In contrast, the decrease in Na+ and Cl− concentrations during winter/spring storms was much greater than that observed during summer/fall storms. Data show that while base flow anion deficit was higher in summer/fall than in winter/spring, anion deficit decreased during most summer/fall storms. In contrast, base flow anion deficit was lower in spring and winter, but increased during winter/spring storms. Increased SO inf4 sup2− concentration was the main cause of episodic acidification during storms at Reedy Creek, but increased anion deficit indicates organic acids may contribute to episodic acidification during winter/spring storms. Changes in SO inf4 sup2− concentration coincident with the hydrograph rise indicate quick routing of water through the watershed. Saturation overland flow appears to be the likely mechanism by which solutes are transported to the stream during storm flow.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00171638
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  • 7
    Electronic Resource
    Electronic Resource
    Effects of Disturbance on Nitrogen Export from Forested Lands of the Chesapeake Bay Watershed (2000)
    Springer
    Environmental monitoring and assessment 63 (2000), S. 187-197 
    Details
    ISSN: 1573-2959
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract The objective of this research project is to develop, test, validate, and demonstrate an analytical framework for assessing regional-scale forest disturbance in the mid-Atlantic region by linking forest disturbance and forest nitrogen export to surface waters at multiple spatial scales. It is hypothesized that excessive nitrogen (N) leakage (export) from forested watersheds is a potentially useful, integrative "indicator" of a negative change in forest function which occurs in synchrony with changes in forest structure and species composition. Our research focuses mainly on forest disturbance associated with recent defoliations by the gypsy moth larva (Lymantria dispar) at spatial scales ranging from small watersheds to the entire Chesapeake Bay watershed. An approach for assessing the magnitude of forest disturbance and its impact on surface water quality will be based on an empirical model relating forest N leakage and gypsy moth defoliation that will be calibrated using data from 25 intensively-monitored forested watersheds in the region and tested using data from more than 60 other forested watersheds in Virginia. Ultimately, the model will be extended to the region using spatially-extensive data describing: 1) the spatial distribution of dominant forest types in the mid-Atlantic region based on both remote sensing imagery and plot-scale vegetation data; 2) the spatial pattern of gypsy moth defoliation of forested areas from aerial mapping; and 3) measurements of dissolved N concentrations in streams from synoptic water quality surveys.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006427401665
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  • 8
    Electronic Resource
    Electronic Resource
    Reply (1989)
    Springer
    Water, air & soil pollution 47 (1989), S. 179-182 
    Details
    ISSN: 1573-2932
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00469006
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  • 9
    Electronic Resource
    Electronic Resource
    Watershed vs in-lake alkalinity generation: A comparison of rates using input-output studies (1988)
    Springer
    Water, air & soil pollution 39 (1988), S. 263-273 
    Details
    ISSN: 1573-2932
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract As a means of assessing the relative contributions of watershed (terrestrial) and in-lake processes to overall lake/watershed alkalinity budgets, alkalinity production rates for watersheds and low alkalinity lakes were compiled from the literature and compared. Based on net alkalinity production data, derived using wet or bulk deposition data, mean and median alkalinity production for 20 watersheds in North America and Europe were 89 and 69 meq m−2 yr−1 (range 20 to 235 meq m−2 yr−1). For a subset of 10 watersheds with dry deposition data, terrestrial alkalinity production neutralized an additional 35 meq m−2 yr−1 of acidic deposition. For 11 lakes, mean and median in-lake alkalinity generation were 99 and 88 meq m−2 yr−1 (range 22 to 240 meq m−2 yr−1). Analysis of data indicates that for the low alkalinity systems described here, areal alkalinity production rates for watersheds and lakes are approximately equal. This relationship suggests that watershed area to lake area ratio can be used as a convenient estimator of the relative importance of watershed and in-lake sources of alkalinity for drainage lake systems. For precipitation-dominated seepage lakes and other systems where hydrology limits soil-water contact, hydrologic flow paths and residence times can be of overriding importance in determining alkalinity sources. For regions dominated by drainage lakes with high watershed area to lake area ratios (such as the Northeastern U.S.), however, alkalinity budgets are dominated by watershed processes. Omission of in-lake alkalinity consideration for most lakes in such regions would have little impact on computed alkalinity budgets or on predicted response to changes in acidic deposition loadings.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00279473
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