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The statistical structure and filter characteristics of tritium fluctuations in fractured basalt
Author(s) -
Duffy Christopher J.,
Harrison Jack
Publication year - 1987
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1029/wr023i005p00894
Subject(s) - attenuation , basalt , filter (signal processing) , aquifer , tritium , diffusion , spectral line , porosity , soil science , covariance , porous medium , environmental science , geology , groundwater , physics , geotechnical engineering , nuclear physics , mathematics , statistics , thermodynamics , optics , engineering , electrical engineering , geochemistry , astronomy
The statistical structure and spectral‐covariance characteristics of tritium fluctuations are examined from injection of low‐level radioactive waste in a fractured basalt aquifer. The tritium fluctuations are the result of a time‐varying injection well concentration. The integral scale of the fluctuations increases with distance from the source and the observation well spectra are characteristic of a dispersive‐type filter. On the basis of these qualitative attenuation characteristics, a theoretical filter is constructed and transport parameters are estimated. The analysis indicates that environmental tracers may provide a useful extension to controlled tests over large length scales (> 100 m). Although current research has concentrated on the importance of intrinsic variability such as porous media heterogeneities, the present study addresses the control exerted by extrinsic variability as exhibited by source strength fluctuations.