Upper Interbed

1.00E-06 m Lower Interbed

1.00E-05 +

1.00E-04 4

1.00E-03

Saturated Hydraulic Conductivity (cm/sec)

8.0 10.0 12,0 14.0 16.0 18.0
% Clay

Figure 6. Clay content versus saturated hydraulic conductivity for the upper
and lower interbeds from borehole ICPP-SCI-V-215 near the Vadose Zone
Research Park (VZRP) at the Idaho National Engineering and Environmental

Laboratory (INEEL).
REPACKING EXPERIMENT Controlled volume water retention
measurements (Winfield and Nimmo, 2002) were
In addition to the measurements reported performed on the two undisturbed cores from the
above, two undisturbed cores from the highly upper baked zone. These were subsequently
aggregated baked zone sediments of the upper disaggregated and repacked; then the retention
interbed were used to examine the effects of measurements were repeated. Results show the

effect of the disruption of the macroporous
structure on water retention (fig. 8). The retention
curves are shifted to a more negative matric
potential for a given water content in the wet
range, indicating an overall decrease in average
pore size. Pore size distributions were calculated
based on capillary theory which relates the water
retention function to the pore size distribution of
the media; pores of different sizes drain at

structure on water retention characteristics. In
general, the upper interbed contains more fine
mnaterial than the lower interbed, the effects of
which are reflected in the hydraulic properties.
The upper interbed baked zone is macroporous,
containing highly cemented aggregates, while the
baked zone of the lower interbed is highly
oxidized and mainly unconsolidated. Scanning

Electron Microscope (SEM) analysis shows different pressures (Danielson and Sutherland
distinct differences in the sediments from the two 1986). The calculated distributions indicate a
baked zones (fig. 7) and suggests that the decrease in the mean pore size and a narrower
cemented nature of the upper interbed may be due range of sizes in the repacked samples (fig. 8). The
to clay coatings on grains that hardened during creation of a more uniform pore size distribution
basalt deposition. as a result of the destruction of the largest and

15


Table 2. Hydraulic conductivity and water retention data for interbed core samples recovered from
borehole ICPP-SCI-V-215 near the Vadose Zone Research Park at the Idaho National
Engineering and Environmental Laboratory. ND means not determined and -0.01 cm
matric potential is assumed at saturation--Continued

Depth (m), Matric potential Volumetric water Hydraulic
o and n parameters (cm water) content (percent) conductivity (cm/s)

-96.97 0.4318 1.228 x 10-06
-292.92 0.4134 4.093 x 10-07
-587.97 0.4009 8.187 x 10-08
871.32 0.3879 4.093 x 10-08
-2,451.24 0.3737 5.240 x 10-09

-17,067.67 0.2958 ND
47.12 -0.01 0.4786 2.217 x 10-07
a= 0.0050 ND 0.4172 1,048 x 10-07
n=1.0849 ND 0.4157 5.240 x 10-08
-945.91 0.4081 2.620 x 10-08
-1,088.55 0.4007 5.240 x 10-09

-1,654.32 0.3874 ND

-8,962.61 0.3836 ND
47.42 -0.01 0.4964 1.660 x 10-07
a = 0.0062 ND 0.4505 1.067 x 10-07
n= 1.059 ND 0.4415 5.335 x 10-08
-805.01 0.4417 2.668 x 10-08
-1,707.63 0.4381 5.335 x 10-9

-1,916.38 0.4267 ND

-11,107.86 0.4235 ND
58.36 -0.01 0.5542 3.356 x 10-04
a=0.4077 -69.50 0.2828 1.637 x 10-5
n= 1.2260 -99.92 0.2407 7.277 x 10-6
-110.54 0.2301 3.275 x 10-06
-139.81 0.2137 1.228 x 10-6
-174.63 0.2020 4.093 x 10-07
-215.83 0.1921 8.187 x 10-08
-364.60 0.1741 3,095 x 10-08
-605.98 0.1582 5.240 x 10-09

-21,565.00 0.0888 ND
58.55 -0.01 0.5681 1.421 x 10-3
= 0.2830 -105.72 0.3047 1.667 x 10-05
n= 12154 -128.21 0.2717 7.410 x 10-06


methods: in A. Klute, ed., Methods of Soil
Analysis, Part 1, American Society of
Agronomy, Soil Science Society of America,
Madison, Wisc., p.687—734.

Mann, L.J., 1986, Hydraulic properties of rock
units and chemical quality of water for INEL-
1— a 10,365-foot deep test hole drilled at the
Idaho National Engineering Laboratory,
Idaho: U.S. Geological Survey Water-
Resources Investigations Report 86-4020
(IDO-22070), 23 p.

Nimmo, J.R., Perkins, K.S., and Lewis, A.M.,
2002a, Steady-state centrifuge: in Dane, J.H.,
and Topp, G.C., eds., Methods of soil
analysis, Part 4: Physical methods, American
Society of Agronomy, Soil Science Society of
America, Madison, Wisc., p. 903-916.

Nimmo, J.R., Perkins, K.S., Rose, P.A., Rousseau,
JP., Orr, B.R., Twining, B.V., and Anderson,
S.R., 2002b, Rapid transport of naphthalene
sulfonate tracer in the unsaturated and
saturated zones near the Big Lost River flood-
control areas at the Idaho National
Engineering and Environmental Laboratory:
Vadose Zone Journal, v. 1, p. 89-101.

Nimmo, J.R., and Mello, K.A., 1991, Centrifugal
techniques for measuring saturated hydraulic

conductivity: Water Resources Research, v.
27, p. 1263-1269.

Nimmo, J.R., Rubin, J., and Hammermeister, D.P.,
1987, Unsaturated flow in a centrifugal field:
measurement of hydraulic conductivity and
testing of Darcy's law: Water Resources
Research, v. 23, p. 124-134.

U.S. Department of Agriculture, 1951, Soil survey
manual, p. 208.

van Genuchten, M.Th., 1980, A closed-form
equation for predicting the hydraulic
conductivity of unsaturated soils: Soil
Science Society of America Journal, v. 44, p.
892-898.

van Genuchten, M.Th., Leij, F.J., and Yates, S.R
1991, The RETC Code for quantifying the
hydraulic functions of unsaturated soils: U.S.
Environmental Protection Agency, EPA/600/
2- 91/065, 85 p.

Winfield, K.A., and Nimmo, J.R., 2002,
Controlled liquid-volume, in Dane, J.H. and
Topp, G.C. eds., Methods of soil analysis,
Part 4: Physical methods, American Society
of Agronomy, Soil Science Society of
America, Madison, Wisc., p. 698-703.


CONVERSION FACTORS

Multiply By To obtain
Centimeter (cm) 0.3937 Inch
Meter (m) 3.281 Foot
Square kilometer (km?) 0.3861 Square mile
Cubic centimeter (cm?) 0.06102 Cubic inch

iv


Upper interbed baked zone

Figure 7. Core photographs and scanning electron microscope images for samples
from the upper and lower interbed baked zones from borehole ICPP-SCI-V-215
near the Vadose Zone Research Park (VZRP) at the Idaho National Engineering
and Environmental Laboratory (INEEL).

16


smallest pores would be expected to result in a
steepening of the drainage retention curve (i.e.
many pores of comparable size draining at about
the same time), which is indeed the case.

CONCLUSIONS

The two interbeds at the location of ICPP-
SCI-V-215, approximately 3 km southwest of the
INTEC, have saturated hydraulic conductivity
values that range over four orders of magnitude
from 1.42 x 10-3 cm/s for loamy sand to 1.66 x
10-°7 cm/s for silt loam. During high infiltration
that occurs episodically from the Big Lost River
and due to the disposal of wastewater to
infiltration ponds, these interbeds, especially the
upper interbed, may cause perching that leads to
lateral flow through more permeable layers and
overlying basalts. The baked zones in these
interbeds are probably not the main influence on
perching at this location.

The results presented here are consistent with
those of past studies in showing a high degree of
heterogeneity in the interbeds and, therefore, the
need for analysis of a large number of samples
from various locations and interbeds. Once further
measurements are completed and the interbeds are
better characterized, correlations between
hydraulic properties and particle size distributions
may permit the subsurface hydrology of other
areas of the INEEL to be more easily assessed.

REFERENCES

Anderson, S.R., 1991, Stratigraphy of the
unsaturated zone and uppermost part of the
Snake River Plain aquifer at the Idaho
Chemical Processing Plant and Test Reactors
Area, Idaho National Engineering Laboratory,
Idaho: U. S. Geological Survey Water-
Resources Investigations Report 91-4010,

TI p.

Bartholomay, R.C., Tucker, B.J., Ackerman, D.J.,
and Liszewski, M.J., 1997, Hydrologic
conditions and distribution of selected
radiochemical and chemical constituents in
water, Snake River Plain Aquifer, Idaho
National Engineering Laboratory, Idaho,
1992 through 1995: U. S. Geological Survey

18

Water-Resources Investigations Report 97—
4086, 57 p.

Bartholomay, R.C., 1998, Distribution of selected
radiochemical and chemical constituents in
perched groundwater, Idaho National
Engineering Laboratory, Idaho, 1992 through
1995: U. S. Geological Survey Water-
Resources Investigations Report 98-4026,

59 p.

Blake, G.R., and Hartge, K.H., 1986, Particle
Density: in A. Klute, ed., Methods of Soil
Analysis, Part 1, American Society of
Agronomy, Soil Science Society of America,
Madison, Wisc., p. 377-382.

Campbell, G.S., and Gee, G W., 1986, Water
Potential: Miscellaneous Methods: in A.
Klute, ed., Methods of Soil Analysis, Part 1,
American Society of Agronomy, Soil Science
Society of America, Madison, Wisc., p. 628—
630.

Cecil, L.D., Orr, B.R., Norton, T., and
Anderson,S.R., 1991, Formation of perched
ground-water zones and concentrations of
selected chemical constituents in water, Idaho
National Engineering Laboratory, Idaho,
1986-88: U. S. Geological Survey Water-
Resources Investigations Report 91-4166,

53 p.

Conca, J.L., and Wright, J.V., 1998, The UFA
method for rapid, direct measurement of
unsaturated transport properties in soil,
sediment, and rock: Australian Journal of Soil
Research, v. 36, p. 291-315.

Danielson, R.E., and Sutherland P.L., 1986,
Porosity: in A. Klute, ed., Methods of Soil
Analysis, Part 1, American Society of
Agronomy, Soil Science Society of America,
Madison, Wisc., p. 444-445.

Gee, G.W., and Or, D., 2002, Particle-size
analysis, in Dane, J.H., and Topp, G.C., eds.,
Methods of soil analysis, Part 4: Physical
methods, American Society of Agronomy,
Soil Science Society of America, Madison,
Wisc., p. 255-293.

Klute, A., and Dirkson, C, 1986, Hydraulic
conductivity and diffusivity: laboratory


0.10 015 0.20 0.25 030 035 040 045 0.50 0.55 0.60

1.0E-02 T T T T T T
Upper Interbed

1.0E-03 + Ppe

3 ¢ 45.85 m, Sandy Loam .
R

'E 1.0E-04 4 ® 46.10 m, Sandy Loam
&
> 4 46.37 m, Silt Loam a
= eRe
= 1.0E-05 + 46.45 m, Loam te
3 ® 47.12 m, Silt Loam ae ay
& 1.06-06 | ~ 47.42 m, Silt Loam oan
8 5 om,
Ss e
3 -
® 1.0E-07 eat -
= oa e ]
= e

1.0E-08

en e -
1.0E-09

Water Content (vol/vol)

0.10 015 020 0.25 030 O35 0.40 045 050 055 0.60
1.0E-02 r T r T

1.0E-03 + .
- x x e
8 -
'E 1.0E-04 +
2
2 oxen x °. a
3 1.0E-05 + xo” « .
2 xe om x as
& 1.0E-06 + xe mx a . Lower Interbed
2 xene “ . + 58.36 m, Sand
8 1.0E-07 xen n . = 58.55 m, Loamy Sand
= xe om x a ° 4 59.20 m, Sandy Loam
1.0E-08 + x 59.48 m, Loamy Sand
. xeon os a . ¢ 59.70 m, Sandy Loam
* 59,92 m, Loamy Sand
1.0E-09
Water Content (vol/vol)

Figure 4. Unsaturated hydraulic conductivity data for the upper and lower interbeds
from borehole ICPP-SCI-V-215 near the Vadose Zone Research Park (VZRP) at the
Idaho National Engineering and Environmental Laboratory (INEEL).

13


lava flows and tuffs crop out locally at the surface
and occur at depth below the basalt-sediment
sequence (Mann, 1986). The INEEL occupies
about 2,300 km? of semi-arid, sagebrush-covered
terrain on the northwestern side of the plain. The
INTEC is in the southern part of the INEEL
covering approximately 0.4 km2. The surficial
sediments near the INTEC consist of gravelly
material ranging from 0.6 to 22.2-m deep, being
deepest to the west. In the vicinity of the INTEC,
wells drilled to a depth of 213 m penetrate a
sequence of 23 basalt flow groups and 15 to 20
sedimentary interbeds (Anderson, 1991, fig. 2).

METHODS

During the drilling of borehole ICPP-SCI-V-
215, interbed sediment was cored into
polycarbonate liners (roughly 8.6 cm inner
diameter), capped off at the ends, and transported
to the U.S. Geological Survey (USGS) Menlo Park
Unsaturated Zone Flow Laboratory for analysis.
The samples were cut into smaller recorable
sections using a drill-type tool with a circular
blade. Each section, unless there was obvious
disturbance, was then recored using a mechanical
recoring device. Liners were secured by clamps as
the material was slowly extruded upward into a
5.2-cm long, 3.3-cm diameter retainer with a
sharp-edged custom made stainless steel coring
attachment. The retainers are designed specifically
to fit into the buckets of the UFA!centrifugal
rotor, which was used in the unsaturated hydraulic
conductivity measurements described below
(Nimmo and others, 2002a; Conca and Wright,
1998).

A Coulter LS-230 Particle Size Analyzer!
was used to characterize particle-size distributions
by optical diffraction (Gee and Or, 2002). The
range of measurement for this particular device is
0.04-2,000 xm, which is divided into 116-size
bins. Any particles above 2,000 jum were sieved
out and later integrated into the size-distribution
results. The fraction below 2,000 um was carefully
disaggregated using a mortar and rubber-tipped
pestle, then split with a 16-compartment spinning

1. Use of brand names does not constitute endorsement by
the U.S. Geological Survey

riffler to obtain appropriate random samples for
analysis. The material was sonicated for 60
seconds prior to each run and an average of 2 runs
was calculated for each sample.

The standard falling head method for
obtaining saturated hydraulic conductivity (Kat)
was used for most samples (Klute and Dirkson,
1986). For samples with low saturated
conductivity, a modification of the standard
method (Nimmo and Mello, 1991; Nimmo and
others, 2002a) was performed in a centrifuge with
saturated hydraulic conductivity calculated using
the following equation:

K= (24a) (Apareylin((gzp+ oh Ase; + 075)

where

1 = sample length (4.9 cm in this case),

a = the cross sectional area of the inflow reservoir
(cm),

A= the cross sectional area of the sample (34.8
cm? in this case),

p = the density of the fluid used (1.0 g/cm/ in this
case),

t = time (seconds),

g = gravitational acceleration (9.8 cm/s?),

z= the height of water in the reservoir (cm, initial-
i, and final-f),

r= the radius of rotation at the sample bottom (13
cm in this case), and

@ = angular speed (rad/s).

The lab-saturated moisture content (table 1)
was determined by weight at the end of the
saturated conductivity measurement.

The SCC method used for obtaining
unsaturated hydraulic conductivity is the UFA
version (Conca and Wright, 1998; Nimmo and
others, 2002a) of the method originally developed
by Nimmo and others (1987). Steady-state,
unsaturated flow through a core sample is
achieved relatively quickly using centrifugal force
to drive the liquid flow, with flux through the
sample maintained precisely by a metering pump.
A rotating seal assembly conducts the water from
the pump to the spinning sample. The SSC method
requires that steady-state conditions be established
within a sample under centrifugal force. Steady-
state conditions require a constant flow rate and a


measurements in order to identify any structural
effects.

INTRODUCTION

From 1952-84 low-level radioactive,
chemical, and sanitary wastewater was disposed of
from the Idaho Chemical Processing Plant (ICPP),
now known as the Idaho Nuclear Technology and
Engineering Center (INTEC) (fig. 1), directly to
the Snake River Plain aquifer through a 183-m-
deep disposal well. A wastewater infiltration pond
was completed in February 1984 and used through
1985. A second pond was constructed in October
1985 and used through 1995. An average of 430
million gallons of wastewater per year (1963-93)
was discharged to the deep disposal well and the
unlined infiltration ponds, with an average annual
discharge of 570 million gallons between 1992 and
1995 (Bartholomay and others, 1997). Chloride,
fluoride, nitrate, sodium, and sulfate were the
predominant chemicals discharged to the ponds
between 1992 and 1995 and tritium accounted for
more than 90 percent of the radioactivity in
wastewater discharged at the ICPP since 1970.
Other chemicals found in water samples include
strontium-90, cesium-137, plutonium-239,
plutonium-240, chromium, 1,1,1-trichloroethane,
and various trace elements, such as aluminum,
copper, iron, and manganese (Bartholomay, 1998).
Perched ground-water zones have formed
presumably as a result of the use of the unlined
infiltration ponds to dispose of wastewater. Cecil
and others (1991) identified perched water bodies
at depths of 9.2 m where surficial sediments
contact the uppermost basalt-flow group, at a
25.0 m contact of two basalt flows, at 54.3 m,
possibly due to sedimentary fracture infilling, and
at a 101.2 m-contact between two basalt flow
units. Because of the complex nature of the
subsurface near the INTEC, perching depths likely
vary laterally.

A large-scale tracer experiment conducted in
1999 in the Big Lost River spreading areas (fig. 1)
near the Radioactive Waste Management Complex
(RWMC), approximately 13 km from the INTEC,
showed that rapid lateral flow of perched water
occurs in the unsaturated zone and may therefore
be an important factor in contaminant transport

(Nimmo and others, 2002b). In September 2001, a
new field-scale research facility called the Vadose
Zone Research Park (VZRP) was established in
the vicinity of the INTEC (fig. 2). The park is a
2.6 km* facility for the study of the movement of
water and solutes through unsaturated zone, which
is about 150 m thick at this location. Two new
percolation ponds were constructed to receive
about a million gallons of equipment-cooling
water each day.

Purpose and Scope

This report investigates the hydraulic
characteristics of interbed material at one location
near the INTEC and the possible effect of these
characteristics on flow through the INEEL
unsaturated zone. Saturated and unsaturated
hydraulic properties were measured on minimally
disturbed core samples recovered in the drilling of
borehole ICPP-SCI-V-215 in June 2000 (fig. 2).
These samples, except for the two additional
samples that were repacked to examine structural
effects on water retention, were carefully recored
in the laboratory into the appropriate retainers for
measurement of hydraulic conductivity (K) as a
function of water content (8) using the steady-state
centrifuge (SSC) method (Nimmo and Mello,
1991; Conca and Wright, 1998). Hydraulic
conductivity (K(6)) and matric potential (w)
measurements were carried out on 12 samples
from various depths in two interbeds located at
depth intervals of 45.4 to 47.8 m and 58.2 to
60.4 m. An additional pair of cores from the upper
interbed baked zone was used to examine
structural effects on water retention.

Geohydrologic Setting

The eastern Snake River Plain is a structural
basin about 325-km long and 80 to 110-km wide,
bounded by mountain ranges and high plateaus.
Streams within alluvial valleys separating the
mountain ranges to the north and northwest flow
onto the plain and the INEEL in response to
rainfall and snowmelt. The eastern Snake River
Plain is underlain by a sequence of basaltic lava
flows interbedded with sedimentary deposits. The
sediments consist of fluvial, lacustrine, and eolian
deposits of clay, silt, sand, and gravel. Rhyolitic


Measurement of Sedimentary Interbed Hydraulic Properties
and Their Hydrologic Influence Near the Idaho Nuclear
Technology and Engineering Center at the Idaho National
Engineering and Environmental Laboratory

by Kim S. Perkins

Abstract

Disposal of wastewater to unlined infiltration
ponds near the Idaho Nuclear Technology and
Engineering Center (INTEC), formerly known as
the Idaho Chemical Processing Plant, at the Idaho
National Engineering and Environmental Labora-
tory (INEEL) has resulted in the formation of
perched water bodies in the unsaturated zone
(Cecil and others, 1991). The unsaturated zone at
the INEEL comprises numerous basalt flows inter-
bedded with thinner layers of coarse- to fine-
grained sediments and perched ground-water
zones exist at various depths associated with mas-
sive basalts, basalt-flow contacts, sedimentary
interbeds, and sediment-basalt contacts. Perched
ground water is believed to result from large infil-
tration events such as seasonal flow in the Big
Lost River and wastewater discharge to infiltra-
tion ponds. Evidence from a large-scale tracer
experiment conducted in 1999 near the Radioac-
tive Waste Management Complex (RWMC),
approximately 13 km from the INTEC, indicates
that rapid lateral flow of perched water in the
unsaturated zone may be an important factor in
contaminant transport at the INEEL (Nimmo and
others, 2002b). Because sedimentary interbeds,
and possibly baked-zone alterations at sediment-
basalt contacts (Cecil and others, 1991) play an
important role in the generation of perched water it
is important to assess the hydraulic properties of
these units,

In September 2001, the Vadose Zone
Research Park (VZRP) was established near the
INTEC for study of the movement of water and
solutes through the unsaturated zone. Two new
percolation ponds at the VZRP receive about a
million gallons of equipment-cooling water each
day. The subsurface at this location is much more

complex than that near the RWMC and little is
known about the hydraulic properties of the
sedimentary interbeds. As part of an ongoing
sedimentary interbed characterization project,
hydraulic properties, including saturated and
unsaturated hydraulic conductivity and water
tetention, were measured on 12 cores recovered
from 2 interbeds from borehole ICPP-SCI-V-215
in the vicinity of the INTEC, which was drilled by
the U.S. Geological Survey as a part of the
development of the VZRP.

In general, the upper interbed examined in
this study exhibits hydraulic properties consistent
with higher clay contents than those of the lower
interbed and also contains low permeability layers
that could enhance perching. These interbeds,
which are separated by a relatively thin basalt
flow, also exhibit distinctly different baked-zone
features that are apparent from visual and scanning
electron microscope examination. Heat exposure
from overlying lava flows produces baked zones at
the tops of interbeds due to the dehydration and
oxidation of iron-rich minerals. The baked zone of
the upper interbed is macroporous, containing
highly cemented aggregates, while the baked zone
of the lower interbed contains highly oxidized,
mainly unconsolidated sand. Baked-zone sedi-
ments from both interbeds, although texturally and
structurally different, have comparable, relatively
high saturated hydraulic conductivities.

In order to quantify the effect of the macro-
porous structure of the baked material in the upper
interbed, water retention was measured on 2
undisturbed cores in addition to the 12 cores used
for hydraulic property measurements. Water
retention measurements were performed on the
two undisturbed cores, then the cores were air
dried, disaggregated, and repacked for additional


100

90 Upper Interbed

80} ——=45.85 m, Sandy Loam
=~o- 46.10 m, Sandy Loam

§ 70
= + = +46.37 m, Silt Loam
60] = = -46.45 m,Loam
ae 47.12 m, Silt Loam
2 47.42 m, Silt Loam
& 40
2
2 30
20
10
o
0.01 1000 10000
Particle Diameter (um)
100
90 Lower Interbed

80 — =58.36 m, Sand

= + +58.55m, Loamy Sand
70 === 59,20 m, Sandy Loam
60 59.48 m, Loamy Sand
——59.70 m, Sandy Loam

59.92 m, Loamy Sand

40

Percentage Finer Than
8

30

20

10

0.01 o4 1 10 100 1000 10000
Particle Diameter (um)

Figure 5. Cumulative particle size distributions for the upper and lower interbeds from
borehole ICPP-SCI-V-215 near the Vadose Zone Research Park (VZRP) at the Idaho
National Engineering and Environmental Laboratory (INEEL).

14


EXPLANATION Location of Section

[8] pasatr :

CLAY, SILT, SAND AND GRAVEL

i
—~—" GEOLOGIC CONTACT — Queried where uncertain : ye:
8 oer ow . .
WELL — Entry, 38, is local well identifier. 2° |

crkeg

*
"
s,
ot
a

VZRP
a

22 19 77 Beds

. 2 —

reer ICPP-SCI-V-215 c
5107 C T

5,000

4,900-4

4,700

4900-4

4500

40

4,300:

Figure 2. Subsurface cross section (C-C>) in the vicinity of the Idaho Nuclear
Technology and Engineering Center (INTEC) (modified from Anderson, 1991).
Locations of the Vadose Zone Research Park (VZRP) and borehole ICPP-SCI-V-215
are noted above.




DOE/ID-22183

MEASUREMENT OF SEDIMENTARY INTERBED
HYDRAULIC PROPERTIES AND THEIR
HYDROLOGIC INFLUENCE NEAR THE IDAHO
NUCLEAR TECHNOLOGY AND ENGINEERING
CENTER AT THE IDAHO NATIONAL ENGINEERING
AND ENVIRONMENTAL LABORATORY

U.S. Geological Survey
Water-Resources Investigations Report 03-4048

Upper interbed baked zone Lower interbed baked zone

Prepared in cooperation with the
U.S. DEPARTMENT OF ENERGY



Particle density measurements were
performed with the pycnometer method (Blake
and Hartge, 1986) on all samples. Porosity was
calculated using the measured bulk- and particle-
density values as described by Danielson and
Sutherland (1986).

Because the upper and lower interbed baked
zones were visually quite different, they were
examined using a scanning electron microscope
(LEO 982-Gemini column model, Schottky Field
Emission-SEM!). Baked zone sediments from the
upper interbed were highly aggregated, therefore
water retention was also measured on two
additional cores to examine structural effects using
the controlled volume method (Winfield and
Nimmo, 2002). With this method, water is
incrementally extracted through a porous ceramic
plate and pressure is measured with a tensiometer.
Measurements were performed on the undisturbed
samples which were then air dried, disaggregated
with a mortar and rubber-tipped pestle, rewetted,
and repacked to the original bulk density for
additional measurements. The repacking technique
consisted of adding sample to the retainer, wetting,
tamping, and repeating until the desired bulk
density was reached.

RESULTS AND DISCUSSION

The properties measured in this study include:
bulk density, particle density, particle size
distributions, soil moisture retention, saturated
hydraulic conductivity, and hydraulic conductivity
as a function of water content. Table 1 summarizes
properties including calculated porosity, lab-
saturated water content, saturated hydraulic
conductivity, and U.S. Department of Agriculture
texture classification (U.S. Department of
Agriculture, 1951) for the 12 interbed core
samples. In some cases, the lab-saturated water
content is slightly higher than the calculated
porosity value which may be due to the presence
of excess water on top of the sample during
weighing after the saturated hydraulic conductivity

measurement. Unsaturated hydraulic conductivity
and moisture retention data are presented in
tabular form in table 2 and in graphical form in
figures 3 and 4 respectively. The commonly used
fitted parameters o and n were determined using
the RETC program (van Genuchten and others,
1991) and are included in table 2. This program
performs a non-linear least squares fit to the
measured water retention and hydraulic
conductivity data. The shape factors, a, an
empirical parameter whose inverse is often
referred to as the air entry value (van Genuchten,
1980), and n are required input for many models
describing variably saturated flow.

Summarized particle-size distribution data are
presented in tabular format in table 3 and graphical
format in figure 5. In general, the upper interbed
properties are consistent with a higher clay content
than the lower interbed. Figure 6 shows the
relationship between clay content and saturated
hydraulic conductivity. In general, saturated
hydraulic conductivity decreases as clay content
increases. The water retention results from the two
baked zone cores are discussed separately below.

This study provides vertical profiling of
sedimentary interbed hydraulic properties at one
location and two depth intervals. As earlier
investigations also indicate, the sedimentary
interbeds at the INEEL are highly complex with
variable thickness, texture, and hydraulic
properties. The variability of hydraulic properties
in these samples, especially in the upper interbed,
may be a major influence on perching at this
location. Although the baked zones in these two
interbeds are distinctly different with clay content
having the greatest effect on unsaturated hydraulic
properties, they are not likely to be a major
influence on perching phenomena at this particular
location. The layers below the baked zones where
saturated hydraulic conductivity is low, for
example at depths of 47.12 and 47.42 m, are more
likely to influence perching.


Table 1. Selected interbed properties for core samples from well ICPP—SCI-V—215 near the Vadose Zone
Research Park at the Idaho National Engineering and Environmental Laboratory

Depth (m)

U= upper interbed Calculated Lab saturated water Saturated hydraulic Texture

L=lower interbed porosity (percent) content (cm3/cm3) conductivity (cm/s) (USDA)
45.85 U 0.5730 0.5773 2.17 x 10-04 sandy loam
46.10U 0.5530 0.4914 1.81 x 10-4 sandy loam
46.37 U 0.4829 0.4733 4.68 x 10-05 silt loam
46.45 U 0.4458 0.4516 1.68 x 10-05 silt loam
47.12U 0.4628 0.4786 2.22 x 10-97 silt loam
4742U 0.4673 0.4961 1.66 x 10-07 silt loam
58.36L 0.5587 0.5542 3.36 x 10-04 sand
58.55L 0.5509 0.5681 1.42 x 10-03 loamy sand
59.20L 0.5075 0.5309 1.63 x 10-4 sandy loam
59.48 L 0.4736 0.5182 4.34 x 10-4 loamy sand
59.70 L 0.5403 0.5220 1.25 x 10-04 sandy loam
59.92 L 0.4560 0.4856 3.95 x 10-04 loamy sand

constant centrifugal force for sufficient time that
both the water conditions and the water flux within
the sample are constant. When these conditions are
satisfied, Darcy's law relates K to 6 and y for the
established conditions. With centrifugal instead of
gravitational force, Darcy's law takes the form

q=-K (dy/dr - par)

where

q= the applied flow rate (cm/s),

r= the radius of centrifugal rotation (cm),

p = the density of the applied fluid (g/cm), and
@ = angular speed of rotation (rad/s).

If the driving force is applied with the
centrifuge rotation speed large enough to ensure
that dw/dr << p@?r (i.e. any matric pressure
gradients that develop in the sample during
centrifugation are insignificant) the flow is
essentially driven by centrifugal force alone. The
flow equation then simplifies to

q=-K(y) porr.

The @ threshold for which the dy/dr gradient
can become negligible depends on the soil
hydraulic properties. Nimmo and others (1987)

discussed this gradient and presented model
calculations showing that it becomes negligible at
relatively low speeds for a sandy medium and at
higher speeds for a fine-textured medium. This
technique normally results in a fairly uniform
water content throughout the sample, permitting
the association of the sample average @ values
with the measured y and K. After achieving steady
flow within the centrifuge at a given q, the sample
is removed, 6 is determined by weight, and y is
determined by a non-intrusive tensiometer or with
the filter paper method (Campbell and Gee, 1986)
in cases where suctions exceeded 800 cm. This
method yields a triplet of data: K, 6, and y for the
average moisture conditions within the sample.
Repeat measurements with different g values (and
perhaps different rotational speed) give the
additional points needed to define the K(y), K(6),
and (8) characteristic curves.

The SSC method as described above was
used in this analysis with K, 0, and y measured in
each run. There was no observable compaction of
these samples due to centrifugal force, therefore
the effect of such compaction on the hydraulic
Properties was assumed to be negligible.


Lost River Range

‘To Idaho Faits

ESRP Eastem Snake River Plain
CFA Central Facilities Area
TRA Test Reactor Area

wk TAN Test Area North
By tot = INTEC Idaho Nuclear Technology
River ‘a and Engineering Center
Spreading WMC Radioactive Waste Management
Complex

Figure 1. Map of the Idaho National Engineering and Environmental Laboratory
(INEEL) including the Idaho Nuclear Technology and Engineering Center (INTEC),
Radioactive Waste Management Complex (RWMC) and Big Lost River Spreading
Areas.


Frequency (%)

45.42 m, Undisturbed

—vG Fit

« 45.58 m, Undisturbed -—~vG Fit

06

05

2
FS

© 2
iy e
Water Content (vol/vol)

= 45.42 m Repacked —vG Fit 01
2 45.58 m, Repacked ~-—VG Fit
C)
1.0E+06 = -1.0E+051.0E+04. © 1.0E+03 = 1.06402 1.0E+01—1.0E +00 1.0E-01
Matric Potential (-cm water)
8
7 msn
——45.52 m, Undisturbed ray
64 sone 45.58 m, Undisturbed ff
= = 45.52 m, Repacked Pd 2 v
5 » = 45.58m, Repacked ‘
4
3
24
14 =
err
0 r
1.0E-09 1.0E-07 1.0E-05 1.0E-03 1.0E-01 1.0E+01

Pore Diameter (mm)

Figure 8. Water retention data (above) fit with the van Genuchten function
(van Genuchten, 1980) and pore size distributions (below) calculated from the

water retention data.

17


CONTENTS

ADStract ....cccccecsessessessssesseesscseeseesesecscseesesscssssessessesassasscssessessesueneenesueneeseneescsnensauesesnesssssessissseseesneneennensnneene 1
Introduction

Purpose and scope

Geohydrologic settin;
Methods
Results and discussion
Repacking experiment
Conclusion:
References.

FIGURES

Figure 1. Map showing location of the Idaho National Engineering and Environmental
Laboratory including the Idaho Nuclear Technology and Engineering Center,
Radioactive Waste Management Complex, and Big Lost River Spreading areas...

2. Subsurface cross section (Vin in the vicinity of the Idaho Nuclear Technology and
Engineering Center ..
3. Water retention curves 23 for the upper stand ‘ower interbeds from borehole ICPP-SCI-V-
215 near the Vadose Zone Research Park at the Idaho National Engineering and
Environmental Laboratory....
4. Unsaturated hydraulic conductivity data for the upper and lower interbeds from
borehole ICPP-SCI-V-215 near the Vadose Zone Research Park at the Idaho National
Engineering and Environmental Laboratory.
5. Cumulative particle size distributions for the upper and lower interbeds from borehole
ICPP-SCI-V-215 near the Vadose Zone Research Park at the Idaho National
Engineering and Environmental Laboratory.
6. Clay content versus saturated hydraulic conductivity for the upper and lower interbeds
from borehole ICPP-SCI-V-215 near the Vadose Zone Research Park at the Idaho
National Engineering and Environmental Laboratory...
7. Core photographs and scanning electron microscope images for samples from the upper
and lower interbed baked zones from borehole ICPP-SCI-V-215 near the Vadose Zone

Research Park at the Idaho National Engineering and Environmental Laboratory.............. 16
8. Water retention data fit with the van Genuchten function and pore size distributions
calculated from water retention data........sscessssssessssseeseeseeneecssecsnssteseeesensensessesaessessessnses 17
TABLES

Table 1. Selected interbed properties for core samples from well ICPP-SCI-V-215 near the
Vadose Zone Research Park at the Idaho National Engineering and Environmental
Laboratory

2. Hydraulic conductivity and water retention data for interbed core samples recovered
from borehole ICPP-SCI-V-215 near the Vadose Zone Research Park at the Idaho
National Engineering and Environmental Laboratory

3. Particle size distribution data summary for interbed core samples from borehole
ICPP-SCI-V-215 near the Vadose Zone Research Park at the Idaho National
Engineering and Environmental Laboratory.........ssscsssssseessseeeseesneeneeesneenneessieesneessatesseessey 11

iii


Table 2. Hydraulic conductivity and water retention data for interbed core samples recovered from
borehole ICPP-SCI-V-215 near the Vadose Zone Research Park at the Idaho National
Engineering and Environmental Laboratory. ND means not determined and -0.01 cm
matric potential is assumed at saturation--Continued

Depth (m), Matric potential Volumetric water Hydraulic
o and n parameters (cm water) content (percent) conductivity (cm/s)

7145.34 0.2560 3.335 x 10-06
-162.37 0.2433 1.250 x 10-0
-214.60 0.2238 4.168 x 10-07
-235.04 0.2152 8.336 x 10-08
-303.02 0.2006 3.152 x 10-08
491.30 0.1816 5.335 x 10-09

69,800.00 0.0954 ND
59.20 0.01 0.5309 1.633 x 10-04
= 0.0065 -131.57 0.4453 1.637 x 10-05
n= 14514 -237.42 0.3881 7.277 x 10%
311.34 0.3498 3.275 x 10-06
-334.10 0.3377 1.228 x 10-06
420.60 0.3132 4.093 x 10-07
-513.92 0.2913 8.187 x 10-08
649.29 0.2703 3.095 x 10-08
-764.63 0.2544 5.240 x 10-09

-530.00 0.2520 ND

-1,313.00 0.2485 ND
59.48 -0.01 0.5182 4.341 x 10-04
= 0.0204 -114.95 0.2917 1.637 x 10-05
n=1.6574 -136.47 0.2459 7.277 x 10-%
-153.22 0.2226 3.275 x 10°
-175.39 0.2010 1.228 x 10-06
-212.15 0.1830 4.093 x 10-07
-245.34 0.1707 8.187 x 10-08
-301.78 0.1611 3.095 x 10-08
-390.80 0.1438 5.240 x 10-9

-374.00 0.1407 ND

-585.00 0.1373 ND
59.70 -0.01 0.5220 1.245 x 10-4
= 0.0124 -35.21 0.4060 1.637 x 10-05
n= 1.3000 -62.60 0.3898 7.277 x 10-6
-T1.95 0.3830 3.275 x 10-06


0.70
[ 0.60
050 >
Q
3
Losao =
s
e
to30 §
45.85m ——vG fit 5
* 46.10m ~—~vG fit z
x 46.37m ——VvG fit f 0.20
+ 46.45m ——vG fit
- 4712m —vG Fit | 0.10
= 47.42m —VG Fit
T r r r r r 0.00
1.0E+06 1.0E+05 1.0E+04 1.0E+03 1.0E+02 1.0E+01 1.0E+00 1.0E-01
Matric Potential (-cm water)
0.60
Interbed
0.50
¢ 58.36m —VvG fit
4 58.55m —vG fit ~
« 59.20m —vGfit +040 &
© 59.48m —vG fit $
- 59.70m —vG Fit =
59.92m -~-vG Fit 030 2
8
s
&
fo20 8
+ 0.10
+ : 0.00

1.0E+06 = 1.0E+05 = 1.0E+04 1.0E+03 1.0E+02 1.0E+01 1.0E+00 1.0E-01
Matric Potential (-cm water)

Figure 3. Water retention curves for the upper and lower interbeds from borehole
ICPP-SCI-V-215 near the Vadose Zone Research Park (VZRP) at the Idaho
National Engineering and Environmental Laboratory (INEEL). Data points were
fit with the van Genuchten function (van Genuchten, 1980).

12


U.S. DEPARTMENT OF THE INTERIOR
GALE NORTON, Secretary

U.S. GEOLOGICAL SURVEY
Charles G. Groat, Director

Any use of trade, product, or firm names in this publication is for descriptive
purposes only and does not constitute endorsement by the U.S. Government.

For additional information write to: Copies of this report can be purchased from:
USS. Geological Survey USS. Geological Survey

INEEL, MS 1160 Information Services

P.O. Box 2230 Box 25286, Federal Center

Idaho Falls, ID 83403 Denver, CO 80225


MEASUREMENT OF SEDIMENTARY INTERBED
HYDRAULIC PROPERTIES AND THEIR HYDROLOGIC
INFLUENCE NEAR THE IDAHO NUCLEAR
TECHNOLOGY AND ENGINEERING CENTER AT THE
IDAHO NATIONAL ENGINEERING AND
ENVIRONMENTAL LABORATORY

By Kim S. Perkins

U.S. GEOLOGICAL SURVEY
Water-Resources Investigations Report 03-4048

Prepared in cooperation with the
U.S. DEPARTMENT OF ENERGY

Idaho Falls, Idaho
February 2003


Table 2. Hydraulic conductivity and water retention data for interbed core samples recovered from
borehole ICPP-SCI-V-215 near the Vadose Zone Research Park at the Idaho National
Engineering and Environmental Laboratory. ND means not determined and -0.01 cm
matric potential is assumed at saturation

Depth (m), Matric potential Volumetric water Hydraulic
o. and n parameters (cm water) content (percent) conductivity (cm/s)
45.85 0.01 0.5773 2.173 x 10-04
a= 1.1007 -54.78 0.4623 1.637 x 10-05
n= 1,1296 -73.40 0.4399 7.271 x 10-%
-102.57 0.4207 3.275 x 10-0
“118.11 0.4125 1.228 x 10-06
-135.78 0.4052 4.093 x 10-97
-201.19 0.3882 8.187 x 10-08
-311.83 0.3698 3.095 x 10-08
409.10 0.3595 5.240 x 10-09
46.10 -0.01 0.4914 1.810 x 10-4
@=0.3291 -20.95 0.4346 1,637 x 10-05
n= 1.0602 -37.16 0.4226 7.277 x 10%
-50.72 0.4128 3.275 x 10-0
-59.04 0.4080 1.228 x 10-06
-149.81 0.3898 4.093 x 10-07
-157.59 0.3872 8.187 x 10-08
-224.20 0.3780 3.095 x 10-08
424.49 0.3654 5.240 x 10-09
46.37 -0.01 0.4733 4.675 x 10°05
= 0.0354 -22.26 0.4542 1.637 x 10-05
n= 1.0067 -38.36 0.4439 7.277 x 10%
-64.83 0.4323 3.275 x 10-6
-86.83 0.4266 1.228 x 10-06
-159.31 0.4179 4.093 x 10-07
-361.26 0.4040 8.187 x 10-8
-594.66 0.3924 3.095 x 10-08
-1,620.17 0.3751 5.240 x 10-0
-9,642.34 0.3063 ND
46.45 -0.01 0.4516 1,678 x 10-05
a= 0.0052 42.38 0.4453 1.637 x 10-95
n= 1.0886 46.02 0.4446 7.277 x 10-6
62.69 0.4390 3.275 x 10-06


Table 2. Hydraulic conductivity and water retention data for interbed core samples recovered from
borehole ICPP-SCI-V-215 near the Vadose Zone Research Park at the Idaho National
Engineering and Environmental Laboratory. ND means not determined and -0.01 cm
matric potential is assumed at saturation--Continued

Depth (m), Matric potential Volumetric water Hydraulic

@ and n parameters (cm water) content (percent) conductivity (cm/s)

-131.11 0.3748 1.228 x 10-0

-148.76 0.3731 4.093 x 10-07

-149.88 0.3715 8.187 x 10-08

-242.60 0.3632 3.095 x 10-08

492.44 0.3520 5.240 x 10-09

59.92 -0.01 0.4856 3.946 x 10-04

a = 0.0347 -71.21 0.3616 1.637 x 10-05

n= 1.3102 -90.58 0.3231 7.277 x 10°

-138.10 0.2801 3.275 x 10-06

-171.45 0.2631 1.228 x 10-06

-215.74 0.2501 4.093 x 10-07

-254.62 0.2399 8.187 x 10-08

-357.27 0.2251 3.095 x 10-08

-512.17 0.2100 5.240 x 10-09

Table 3. Particle size distribution data summary (USDA Classification) for interbed core samples
from borehole ICPP-SCI-V-215 near the Vadose Zone Research Park at the Idaho National
Engineering and Environmental Laboratory

Very fine Fine sand Very coarse
Depth Clay Silt sand (400-250 = Mediumsand —_Coarse sand sand
(m) («2ym) = (2-50pnm) (50-100 pm) um) (250-500 pm) (500-1000 um) (1000-2000 pm)
45.85 46 25.0 V7 16.3 22.1 21.0 3.3
46.10 45 20.8 5.0 11.9 16.1 278 14.0
46.37 13.5 64.5 10.9 14.7 0.1 0.0 0.0
46.45 91 50.4 87 19.4 76 3.3 1.5
47.12 15.2 73.0 9.6 23 0.0 0.0 0.0
4742 15.0 66.1 10.3 8.6 0.1 0.0 0.0
58.36 14 17 9.4 32.2 35.8 12.9 0.6
58.55 2.0 16.8 174 43.0 16.9 3.8 0.1
59.20 41 43.4 22.8 20.7 3.8 43 0.9
59.48 19 13.4 28.6 55.0 12 0.0 0.0
59.70 6.5 20.5 48 13.9 19.0 19.7 15.6
59.92 43 19.0 15.9 35.8 20.6 44 0.0

11