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Phosphorus Characterization and Contribution from Eroding Streambank Soils of Vermont's Lake Champlain Basin
Author(s) -
Ishee Eulaila R.,
Ross Donald S.,
Garvey Kerrie M.,
Bourgault Rebecca R.,
Ford Charlotte R.
Publication year - 2015
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq2015.02.0108
Subject(s) - soil water , phosphorus , structural basin , environmental science , hydrology (agriculture) , geology , geomorphology , geotechnical engineering , soil science , chemistry , organic chemistry
Streambank erosion is an important contributor to sediment and nutrient export. This study determined total P (TP), soil‐test P (Modified Morgan's, MM‐P), and the degree of P saturation (DPS) in eroding riparian soils along four Lake Champlain Basin stream corridors. We investigated the relationship between these data and soil texture and with a series of GIS‐derived landscape metrics. We also quantified the potential P load from eroding streambanks using remote sensing. Soil samples were taken from 76 erosion features to a depth of 90 cm on four streams in Chittenden County, Vermont. Mean concentrations of TP and MM‐P were similar among the watersheds and through depth. Neither TP, MM‐P, nor DPS were well related to texture. Metrics from available spatial databases for parent material, soil series, and landscape position were somewhat useful in predicting TP and MM‐P. Eroding streambank soil from 2004 through 2007 in the four streams was estimated to contain from 0.5 to 3.9 Mg of TP and 1.4 to 10.9 kg MM‐P. The mean DPS in each watershed was <18% and, along with low MM‐P concentrations, suggests that eroded streambanks may act as sinks rather than sources of P. The portion of total nonpoint P export potentially contributed by streambank erosion ranged from 6% in the stream with the lowest erosion rate to 30% in the stream with the highest erosion rate. Based on TP values, the P contribution of these streambanks could be considerable, and more information is needed on their actual contribution to bioavailable P in receiving waters. Core Ideas Streambank erosion along four rural and suburban streams was quantified using remote sensing. Total P showed little variation and soil‐test P was low. The degree of P saturation was also quite low, suggesting that these soils may be P sinks. Potential total P from streambank erosion was estimated to be 6–30% of total P stream export.