Regionalization of soil base cation weathering for evaluating stream water acidification in the Appalachian Mountains, USA

• Published in: Environmental pollution (1987) Vol. 162; pp. 338 - 344
• Main Authors: McDonnell, T.C., Cosby, B.J., Sullivan, T.J.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.03.2012; Elsevier
• Subjects: Acidic deposition; Acidification; Acids - analysis; Appalachian Region; Applied sciences; Base cation; Calibration; Cations; Cations - analysis; Continental surface waters; Critical load; Earth sciences; Earth, ocean, space; ecoregions; ecosystems; Empirical analysis; Engineering and environment geology. Geothermics; Environmental Monitoring - methods; Estimates; Estimating; Exact sciences and technology; landscapes; national parks; Natural water pollution; Pollution; Pollution, environment geology; Rivers - chemistry; soil; Soil - chemistry; Streams; United States; Water treatment and pollution; Watersheds; Weathering; wilderness; Appalachian region; United States; Appalachian Mountains; Weathering; Acidification; Critical load; Base cation; Acidic deposition; Atmospheric fallout; Geochemistry; Environmental management; Acid precipitation; Hydrochemistry; Watershed; Surface water; Stream; Water pollution
• DOI: 10.1016/j.envpol.2011.11.025
• ISSN: 0269-7491

Estimation of base cation supply from mineral weathering (BC w ) is useful for watershed research and management. Existing regional approaches for estimating BC w require generalized assumptions and availability of stream chemistry data. We developed an approach for estimating BC w using regionally specific empirical relationships. The dynamic model MAGIC was used to calibrate BC w in 92 watersheds distributed across three ecoregions. Empirical relationships between MAGIC-simulated BC w and watershed characteristics were developed to provide the basis for regionalization of BC w throughout the entire study region. BC w estimates extracted from MAGIC calibrations compared reasonably well with BC w estimated by regression based on landscape characteristics. Approximately one-third of the study region was predicted to exhibit BC w rates less than 100 meq/m 2/yr. Estimates were especially low for some locations within national park and wilderness areas. The regional BC w results are discussed in the context of critical loads (CLs) of acidic deposition for aquatic ecosystem protection. ► Base cation weathering (BC w ) estimates are needed to model critical load of acidity. ► Estimating BC w formerly required generalized assumptions and stream chemistry data. ► We describe a high-resolution approach for estimating BC w for regional application. A new approach is described for deriving regional estimates of effective base cation weathering using empirical relationships with landscape characteristics.