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Title: Multiple-Year Water Balance of Soil Covers in a Semiarid Setting

Abstract

Surface covers are used to close hazardous and low-level radioactive sites for time frames ranging from hundreds of years to millennia or more. In the absence of data for such durations, the long-term performance of such barriers can only be represented with short-term tests or inferred from analogs and modeling. This paper provides evidence of field performance of soil covers for periods up to 17 years. The results of lysimeter studies from a semi-arid site in Washington State show that a soil cover of 1.5 m of silt loam above a sand/gravel capillary break can eliminate drainage. The results were similar if plants were present or not, demonstrating the robustness of the design. Furthermore, reducing the silt loam thickness to 1.0 m (as might occur via erosion), with or without plants, did not lead to drainage. When irrigated to mimic 3x precipitation conditions, the vegetated Hanford Barrier continued to prevent drainage. Overall, the results showed no diminution in performance during the 17 years of testing. Only when plants were eliminated completely from the 3x precipitation test did drainage occur (rates ranged from 6 to 16 mm/yr). In a separate test, replacing the top 0.2 m of silt loam with dunemore » sand and reducing the plant cover did not lead immediately to the onset of drainage, but soil matric heads within the silt loam noticeably increased. This observation suggests that dune sand migration onto a surface cover has the potential to reduce a cover’s ability to minimize deep drainage.« less

Authors:
;
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
881086
Report Number(s):
PNNL-SA-43141
Journal ID: ISSN 0047-2425; JEVQAA; 830403000; TRN: US200612%%753
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Environmental Quality, 35(2):366-377; Journal Volume: 35; Journal Issue: 2
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; DESIGN; DRAINAGE; LOAM; LYSIMETERS; PERFORMANCE; PRECIPITATION; SAND; SILT; SIMULATION; SOILS; TESTING; THICKNESS; WATER

Citation Formats

Fayer, Michael J., and Gee, Glendon W. Multiple-Year Water Balance of Soil Covers in a Semiarid Setting. United States: N. p., 2006. Web. doi:10.2134/jeq2004.0391.
Fayer, Michael J., & Gee, Glendon W. Multiple-Year Water Balance of Soil Covers in a Semiarid Setting. United States. doi:10.2134/jeq2004.0391.
Fayer, Michael J., and Gee, Glendon W. Wed . "Multiple-Year Water Balance of Soil Covers in a Semiarid Setting". United States. doi:10.2134/jeq2004.0391.
@article{osti_881086,
title = {Multiple-Year Water Balance of Soil Covers in a Semiarid Setting},
author = {Fayer, Michael J. and Gee, Glendon W.},
abstractNote = {Surface covers are used to close hazardous and low-level radioactive sites for time frames ranging from hundreds of years to millennia or more. In the absence of data for such durations, the long-term performance of such barriers can only be represented with short-term tests or inferred from analogs and modeling. This paper provides evidence of field performance of soil covers for periods up to 17 years. The results of lysimeter studies from a semi-arid site in Washington State show that a soil cover of 1.5 m of silt loam above a sand/gravel capillary break can eliminate drainage. The results were similar if plants were present or not, demonstrating the robustness of the design. Furthermore, reducing the silt loam thickness to 1.0 m (as might occur via erosion), with or without plants, did not lead to drainage. When irrigated to mimic 3x precipitation conditions, the vegetated Hanford Barrier continued to prevent drainage. Overall, the results showed no diminution in performance during the 17 years of testing. Only when plants were eliminated completely from the 3x precipitation test did drainage occur (rates ranged from 6 to 16 mm/yr). In a separate test, replacing the top 0.2 m of silt loam with dune sand and reducing the plant cover did not lead immediately to the onset of drainage, but soil matric heads within the silt loam noticeably increased. This observation suggests that dune sand migration onto a surface cover has the potential to reduce a cover’s ability to minimize deep drainage.},
doi = {10.2134/jeq2004.0391},
journal = {Journal of Environmental Quality, 35(2):366-377},
number = 2,
volume = 35,
place = {United States},
year = {Wed Mar 01 00:00:00 EST 2006},
month = {Wed Mar 01 00:00:00 EST 2006}
}