HYDROGEOLOGIC REPORT SHELLER-GLOBE CORPORATION LANDFILL KEOKUK, IOWA EPA Site ID# IAD980630750 EPA Contract No.: 68-W9-0006 Work Assignment No.: C07009 EPA Work Assignment Manager: Anne Olberding Controller Project Manager: John H. Parks prc 30324997 Superfund PRC Environmental Management, Inc.
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HYDROGEOLOGIC REPORT
SHELLER-GLOBE CORPORATION LANDFILL KEOKUK, IOWA
EPA Site ID# IAD980630750
EPA Contract No.: 68-W9-0006 Work Assignment No.: C07009
EPA Work Assignment Manager: Anne Olberding Controller Project Manager: John H. Parks
3.1.1 Study Area...................................................................................................... 23.1.2 Site Location.................................................................................................... 23.1.3 Site Description.............................. 2
3.2 SITE HISTORY.......................................................................................................... 4
4.0 INFORMATION RESOURCES .................. 4
4.1 GENERAL REFERENCE .......................... 44.2 PUBLISHED BULLETINS AND ARTICLES......................................................... 54.3 TECHNICAL REPORTS .......................................................................................... 5
(straight contour lines), or sink hole alignments. In order to determine if large scale fracturing is
present in the study area, a detailed fracture trace analysis using aerial stereo pair photographs is
needed. The topographic maps of the study area do reveal many fracture traces that connect the
ground water regimes. Figure 5-4 is a fracture trace concept diagram showing the hypothetical
appearance of fractured bedrock in the subsurface (Lattman and Parizek, 1964).
Figure 5-5 is a topographical map of the study area with some interpreted fracture traces.
The map shows that there are numerous linear features in the study area.
5.1.3 Fluvial Deposits
The Mississippi River valley is a partially-filled trough, incised into the surrounding
bedrock. The grain size of the sediments typically becomes finer upward through the sequence.
The thickness of the alluvium is controlled by irregularities in the bedrock surface. Regionally,
the maximum thickness of the alluvium is up to 200 feet (Keys, 1895).
The exploration of the Gordon Paleo channel has been limited. Based on available
information, the lower portion of this trough has traces of sand and gravel that are remnants of a
pre-glacial river deposits. These inter-bedded sands and gravels are an important water supply
locally. This channel usually has one or two sand layers that will yield enough water for domestic
needs (Coble, 1971). Obviously, there is sufficient water percolating through the glacial clay till
to recharge these sand layers. Similarly, the bedrock in contact with these deposits will be
recharged through this process.
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FIGURE 5-4: FRACTURE TRACE CQNCEPT
12 PROEM!
FIGURE 5-5: KEOKUK AREA FRACTURE TRACE MAPPRC-EMI
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5.1.4 Soil
The soils within the study area consist of glacial, eolian, and colluvial and alluvial soils of
Pleistocene to Holocene age, and residual soils formed by the in situ weathering of the bedrock.
The site area soils consist of four major types in descending order: the Clinton silt loam,
the Weller silt loam series, the Lindley loam, and the Keswick series. The soils are distributed
similar to Figure 5-6.
The Clinton silt loam is formed on upper side slopes and high benches along major
streams and rivers. It is found in leached loess, 6-to 10-feet thick.
The Weller silt loam series consists of moderately well drained soils on convex summits
and side slopes of upland ridges. These soils formed in leached loess, 4-to 8-feet thick.
The Lindley loam consists of well drained soils on the rounded ends of narrow ridge tops
and irregular, complex, side slopes on uplands.
The Keswick series consist of moderately well drained soils on narrow ridge tops and
convey short side slopes. These soils developed in previously weathered glacial till (USDA, 1979).
All of these soil types are considered well drained because of the water’s ability to
migrate through the material (USDA, 1979). The till in the area has been studied in detail, and
the Iowa Geologic Survey Publication on Illinoisan and pre-Illinoisan stratigraphy of southeast
Iowa and adjacent Illinois has mapped the tills of the area. The till has been identified as the
Hickory Hills till, member of the Wolf Creek Formation tills and is in the pre-Illinoisan;
Yarmouth stage. The Hickory Hills till member is relatively sandy and has sand fractions of 45-
to 50-percent through the study area (Hallberg, 1980).
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REFERENCE: USDA.1979
5-6 TYPICAL SOILS DIAGRAM
PRC-EMI
i s
6.0 HYDROLOGY
6.1 PRECIPITATION
The normal average precipitation for Keokuk, Iowa, is approximately 34.6 inches per year
and the evaporation rate is 23 inches per year; therefore, the net .precipitation is 11.6 inches per
year. Seventy-five percent of the annual precipitation occurs during the 6 month period from
April to September. June is usually the wettest month, and dry periods are most likely in July
(USDA, 1979). The I-year, 24-hour, precipitation event is approximately 2.75 inches (USEPA,
1982). Ten to 20 percent of the precipitation infiltrates into the groundwater system and is the
primary source of recharging for the aquifers in the region (Karsten and Burkart, 1985).
6.2 SURFACE WATER
The study area lies in the Mississippi River drainage area. The surface water within the
study area flows either east to the Mississippi or south to the Des Moines River. The ground
elevation of the site is approximately 640 feet above sea level, while the elevation of the
Mississippi River, approximately 1-1/2 miles east, is 518 feet above sea level (USGS, 1975).
6.3 AQUIFER CHARACTERISTICS
The depth to the water table is approximately 8 feet below ground level in the valley
(E&E/FIT, 1988). The water table elevation will fluctuate in response to precipitation and
climatic conditions.
Ground water within the study area is produced from a variety of sources. The alluvial
sands and gravels along the Mississippi River produce large amounts of drinking water. Stratified
sands and gravels in the Gordon Paleo channel produce water along with bedrock wells drilled
into the St. Louis, Keokuk, and Burlington Formations.
The deposits possibly impacted by the study area can be divided into seven general
hydrogeologic units: the glacial deposits aquifer; the alluvial aquifers; the St. Louis Formation; the
Warsaw Formation; the Burlington-Keokuk Formation; the Prospect Formation; and the
McCraney Formation (see Figure 5-3).
The glacial deposits consist of sand, gravel, silt and clay, and have a variety water
bearing capacities. Yields range from a few gallons-per-minute to large yields of 50-to 100-
gallons- per-minute (Gordon, 1980).
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The alluvial aquifers consist of sand, gravel, silt, and clay, with yields from 25-to 100-
gallons-per-minute. This aquifer is present along the Mississippi River and is recharged rapidly
by the infiltration of surface waters. This alluvium has many high production wells in the region
(Gordon, 1980).
In the Mississippian bedrock, specific capacity of most wells in the area is much less than
1 gallon per minute per foot of drawdown (9 pm/ft). Yields are generally 3-to 10-gallons-per-
minute (gpm) in the St. Louis Formation. Yields in the Burlington-Keokuk and McCraney
Formations are reported at 10-to 30-gpm. Variations in production are directly related to the
degree of interconnection between the well location and the surrounding aquifers (Horick and
• Steinhilber, 1973).
These aquifers are separated by bedrock units of lower hydraulic conductivity; the
Warsaw Formation and the Prospect Formation are considered aquitards. Because of extensive
fracturing and erosion, these beds are not continuous over the study area. The percolation of
groundwater through portions of these beds may be slowed, but it is not prevented from
migrating. The migration of water through these low conductivity beds would therefore
eliminate them from being considered aquicludes.
Ordinarily, a clay or shale formation is nearly impermeable and is called an aquiclude,
i.e., a formation through which virtually no water moves. Formations that do yield some water,
but usually not enough to meet even modest demands, are called aquitards. In reality, almost all
formations will yield some water, and therefore are classified as either aquifers or aquitards. In
water-poor areas, a formation producing small quantities of water may be called an aquifer,
whereas the same formation in a water-rich area would be an aquitard (Driscoll, 1986).
6.4 GROUNDWATER FLOW
Regional groundwater flow in the upper elevations is generally toward the Mississippi
River. The deeper aquifers (Devonian-and Ordovician-aged) generally flow toward the west
following the regional dip of the bedrock.
The migration of water through the subsurface is not controlled by the specific matrix
permeability, but with a two-domain flow concept for soil water flow. Water flow utilizing a
two-domain system could allow rapid vertical and horizontal transport of fluids.
The two-domain soil water flow system is composed of a rapid flux, flowing through
fractures or channels; and a slow flow, flowing through very small pores created by soil particle
contacts. This phenomenon is the same as that of the Burlington-Keokuk limestone below the
site. The rapid water flow and the slow flow both occur in the macropores.
Recent research has shown that the predictive models of contaminant migration have not
correlated between predicted and observed containment migration. The presence of macropores
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has allowed the migration of material deep into the subsurface. The transport of particles
through macropores also allows for the "tunneling out" of pores to increase size and velocities.
The typical permeability test conducted on soils measures only the micropore flow and
does not address the possibility of a macropore adjacent to the sample point. This factor can lead
to the conclusion that materials will not migrate through a soil when in actuality the flow is many
orders of magnitude greater. Likewise the migration of water within the bed rock is primarily
controlled by joints and fractures. The water is available in irregularly spaced and unpredictable
crevices and passages dissolved along bedding planes and vertical fractures by percolating
groundwater.
The groundwater flow system in the study area is very complex with multiple flow
pattern possibilities. The limestone and shale bedrock formations are recharged from
precipitation that infiltrates through the glacial till and loess deposits. The water then begins to
percolate vertically through the bedrock via secondary hydraulic conductivity features such as
joints, faults, fractures, or solution channels (macropores). To a minor extent, water can flow
vertically via existing primary hydraulic conductivity. Vertical movement of groundwater is
complicated by the presence of less permeable shale units. Typically, groundwater may flow
horizontally along bedding planes forming solution channels and continue vertically at the next
open permeable fracture zone. A portion of the bedrock groundwater may discharge to the
surface via springs and seep east of the site in the lower elevation areas. The remainder of the
bedrock groundwater may ultimately discharge into the Mississippi River alluvium, the Gordon
Paleo channel deposits or into the Mississippi River itself. The remaining portion will be stored
in aquifers. Pumping wells may influence the flow patterns by withdrawing water thus altering
normal flow gradients and possibly even reversing them.
6.5 CONTAMINANT TRANSPORT
A potential pollution hazard to the Mississippian aquifer exists in the outcrop area, which
includes the study area. The aquifer in the outcrop area is recharged through the glacial drift;
therefore, any deleterious materials introduced into the surficial flow system eventually will reach
the Mississippian aquifer. Deleterious materials may be in the form of farm chemicals that are
over-applied and infiltrate the ground or may be downward percolating leachate produced from
waste-disposal sites (Horick and Steinhilber. 1973).
The analytical results of several sampling sequences are important to the establishment of
the interconnection between the upper and lower aquifers. The surface soils have been sampled
and analyzed, and found to contain a wide variety of contaminants most notable of which are
lead and zinc. These metals are common constituents of paint wastes deposited at the site
(E&E/FIT, 1988).
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Shallow monitoring wells installed at the site have detected significant levels of arsenic,
chromium, nickel, lead, and zinc (E&E/FIT, 1988).
The Grimes’ well has been sampled three times (E&E/FIT, 1988). The initial sampling
was in October, 1980, by Sheller-Globe. At that time the well was newly drilled . No
contaminants were detected in that sampling (EPA, 1983). The well was sampled again in March
of 1986, when 3700 ug/I of zinc and 55 ug/1 of lead were detected (E&E/FIT, 1988). The final
sampling was conducted in December 1987. The samples showed 6600 ug/1 zinc and 35 ug/1 lead.
Background wells completed upgradient and in the same formation have not contained detectable
amounts of these metals (E&E/FIT, 1988).
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7.0 CONCLUSIONS
Based on the information presented in this report, the separation of the aquifers in the
three-mile radius within the site has not been clearly defined. The area consists of a complex
aquifer-aquitard system of heterogeneous and anisotropic formations and is much more difficult
to define.
The 34 inches of precipitation falling onto the land surface in and around the site is the
source of recharging for the surface aquifers, the St. Louis and Burlington-Keokuk Formations
below the site. Ten-to 20-percent of that precipitation is the primary source of recharging for all
the aquifers in Iowa. This water infiltrates through primary hydraulic conductivity and through
secondary hydraulic conductivity into the aquifers of the region. The secondary hydraulic
conductivity can be responsible for a majority of the transport of groundwater. The fracturing
of the bedrock gives preferential flow paths for rapid transport of both water and contaminants
into aquifers. The aquitards of the region are affected by the fracturing along with erosional
processes to limit the true nature of an aquitard. The aquitards of the area do not function as
aquicludes and therefore allow migration of water into the aquifers below them.
The migration of surface water into the subsurface allows for the transport of
contaminants into the aquifers along with the flow of water. The contaminant transport process
places the entire Mississippian aquifer at risk of being contaminated. With the rapid flow of
water, the contaminants can be carried deep into the aquifer and spread over large areas.
Analytical results from wells on-site have documented that heavy metals have been
released into the groundwater system. The water from the Grimes’ well completed in the lower
Mississippian aquifer has been analyzed and has shown an increase in heavy metal content. This
report documents the presence of interconnections between the upper water table and lower
Mississippian aquifers below the site.
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8.0 BIBLIOGRAPHY
Driscol, Fletcher G., 1986, Groundwater and Wells, Johnson Division, St. Paul, Minnesota.
Ecology & Environment/FIT, 1986, Site Inspection of the Grimes Property Site.
Freeze, Allen R., and John A. Cherry, 1979, Ground Water, Prentice-Hall, Inc., Englewood Cliffs, N.J.
Hallberg, George R., 1980, Pre-Wisconsinan Stratigraphy in Southwest Iowa, Iowa Geologic Survey Technical Information, Series No. 11.
Hansen, Robert E., 1973, Bedrock Topography of Southeast Iowa, U.S. Geological Survey, Washington, D.C.
Horick, P.J., and W.L. Steinhilber, 1973, Mississippian Aquifer of Iowa, Iowa Geological Survey, Miscellaneous Map Series 3.
Iowa Geologic Survey, 1971, Water Resources of Southeast Iowa, Water Atlas No. 4.
Karsten, Richard, and Michael Burkart, 1984, National Water Summary-Iowa, U.S. Geological Survey, Reston, Virginia.
Keyes, Charles R., 1895, Geology of Lee County, Iowa Geological Survey, Vol. Ill,Second Annual Report.
Lattman, L.H., and R.R. Parizek, 1964, Relationship Between Fracture Traces and theOccurrence of Groundwater in Carbonate Rocks, Journal of Hydrology, Volume 2.
Norton, W.H., 1912, Underground Waters of the Southeastern District: Lee County, Iowa Geologic Survey, Annual Reports, Volume XXI.
U.S. Department of Agriculture, 1979, Lee County Soil Survey, Soil Conservation Service.
U.S. Environmental Protection Agency, 1982, HRS User’s Manual.
U.S. Environmental Protection Agency, 1983, Potential Hazardous Waste Site.