![thumbnail](/imgsizer/_?f=PNG&u=https%3A%2F%2Fpubs.usgs.gov%2Fthumbnails%2Foutside_thumb.jpg&w=200&s=b'-UwlSoO6uTLlOIGHeaWA9bd7s68')
Use of borehole neutron logs to estimate moisture content in the unsaturated zone of an alluvial aquifer
Links
- The Publications Warehouse does not have links to digital versions of this publication at this time
- Download citation as: RIS | Dublin Core
Abstract
he neutron borehole logging tool was calibrated for the determination of moisture content in theunsaturated zone of an alluvial aquifer. A continuous core sample was collected to a depth of 15 ft from the unsaturated zone.Moisture content and other soil properties were determined by standard soil-laboratory techniques. The neutron logs profile was correlated to moisture content. The first correlation included all the data points within the unsaturated zone. A correlation coefficient of 0.72 was obtained. An inspection of the plotted data showed that points at the upper extreme of the fitted line departed significantly. A second correlation was tried eliminating data points 1, 3, and 5 which fell too low in the first trial. An almost perfect correlation coefficient of 0.99 was obtained for the data points that were included in the second trial. The criteria used to select the data points for the second correlation trial was that all these points also fell on the left most limit of the neutronprofile. The neutron logs profile, which is like a type of harmonic curve seems to be affected by an undefined factor. Analyzing the shape of the neutron profile it is inferred that hysteresis is the most probable phenomena that is affecting this moisture content profile. Although correlating neutron logs to moisture content is not a straight forward procedure, with an appropriate analysis, calibrated neutron logging tools can be used to determine the moisture content within the unsaturated zone of aquifers. Moisture content should be determined for calibration purposes at least at every foot of depth. Measurements of other elements or factors which may produce the harmonic curve effect might be included in further studies.
Publication type | Conference Paper |
---|---|
Publication Subtype | Conference Paper |
Title | Use of borehole neutron logs to estimate moisture content in the unsaturated zone of an alluvial aquifer |
Year Published | 1986 |
Language | English |
Publisher | Puerto Rico Water Resources Association |
Publisher location | San Juan, P.R |
Contributing office(s) | Caribbean Water Science Center |
Description | 4 p. |
Larger Work Type | Conference Paper |
Larger Work Subtype | Conference Paper |
Larger Work Title | Proceedings of the Third Caribbean Islands Water-Resources Congress |
First page | 57 |
Last page | 60 |
Conference Title | Third Caribbean Islands Water-Resources Congress |
Conference Location | U.S. Virgin Islands |
Conference Date | July 22-25, 1986 |
Online Only (Y/N) | N |
Additional Online Files (Y/N) | N |
Google Analytic Metrics | Metrics page |