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Title: Quantifying sediment provenance using multiple composite fingerprints in a small watershed in Oklahoma

Author
item Zhang, Xunchang
item LIU, BENLI - Beijing Normal University
item LIU, BING - Oklahoma State University
item ZHANG, GUANGHUI - Beijing Normal University

Submitted to: Journal of Environmental Quality
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/28/2016
Publication Date: 7/7/2016
Citation: Zhang, X.J., Liu, B., Liu, B., Zhang, G. 2016. Quantifying sediment provenance using multiple composite fingerprints in a small watershed in Oklahoma. Journal of Environmental Quality. 45:1296-1305.

Interpretive Summary: Sediment source information is badly needed for calibration and validation of process-based soil erosion models. However, sediment source data are rather limited due to difficulties in direct measurement of various source contributions at a watershed scale. The objectives are to estimate sediment source contributions in a 15 km2 watershed using multiple composite fingerprints and to compare the results with those estimated with a single radionuclide 137Cs. Three sediment sources (21 surface soil samples from croplands, 19 from rangelands, and 26 from gully bank) were studied. Thirty one elements were analyzed. All tracers were screened using statistic tests and range checks. The mean concentrations of all the non-conflict tracer pairs were used to calculate source contributions for the three sources. Results showed that though source contributions were strongly influenced by topography and land use, gully or subsoil erosion was found to be the main source of the fine sediment in most sub-watersheds. This work demonstrated that estimated source contributions varied substantially among different composite fingerprints and that the use of multiple composite fingerprints greatly improved accuracy while reduced uncertainty. The source contributions estimated using the multiple composite fingerprint approach agreed well with those estimated with the 137Cs radionuclide, with a correlation coefficient of 0.69 for gully contributions. The good agreement bolstered our confidence in the multiple composite fingerprint method. This work will be useful to erosion scientists and soil conservationists for estimating sediment source contributions so that soil conservation measures can be precisely placed where the most erosion is.

Technical Abstract: Quantitative information on sediment provenance is badly needed for calibration and validation of process-based soil erosion models. However, sediment source data are rather limited due to difficulties in direct measurement of various source contributions at a watershed scale. The objectives are to estimate sediment source contributions in a 15 km2 watershed using analytical solutions to a three end-member mixing model using multiple composite fingerprints and to compare the results with those estimated with a single radionuclide 137Cs. Twenty three surface soil samples from croplands, 19 from rangelands, and 26 from gully bank were collected. Thirty one elements were analyzed. All tracers were screened using statistic tests and range checks. The mean concentrations of all the non-conflict tracer pairs were used in the mixing model to calculate source contributions for the three sources. Results showed that though source contributions were strongly influenced by topography and land use, gully or subsoil erosion was found to be the main source of the fine sediment in most sub-watersheds. This work demonstrated that estimated source contributions varied substantially among different composite fingerprints and that the use of multiple composite fingerprints greatly improved accuracy while reduced uncertainty. The source contributions estimated using the multiple composite fingerprint approach agreed well with those estimated with the 137Cs radionuclide, with a correlation coefficient of 0.69 for gully contributions. The good agreement bolstered our confidence in the multiple composite fingerprint method.