|
-
Groundwater, Surface Water, Flow and Water Level Monitoring
Second Quarter 2002
Bennett's Dump, Monroe County, Indiana
September 24, 2002
1.0 BACKGROUND
This report summarizes the results of groundwater, surface water, flow and water level
monitoring work completed by Viacom Inc. during the second quarter of 2002 at the Bennett's
Dump site.
Groundwater and surface water monitoring was performed at a total of nine locations (springs,
streams and monitor wells) in accordance with the April 2002 Long Term Groundwater
Monitoring Plan (LTGWMP) and the March 2002 Groundwater Investigation Plan (GIP) for this
site. Continuous monitoring of flow and water levels was also performed at six locations
selected by Viacom to promote the understanding of relationships between flows under storm
and non-storm conditions, and the resulting PCB concentrations in groundwater and surface
water at this site.
2.0 GROUNDWATER AND SURFACE WATER MONITORING
The monitoring work described in this report was performed on April 30, May 22 and June 14,
2002. This three month time period constitutes the second reporting quarter for Bennett's Dump
for 2002.
Scope of Work
The scope of groundwater sampling for this monitoring period comprised a combination of
monthly and quarterly sampling stipulated in the LTGWMP and GIP, as summarized in Table 1.
Groundwater and surface water sampling was performed at the following locations:
-
Stout's Creek Upstream
-
Stout's Creek Downstream
-
Mound Spring
-
Middle Spring
- Mid-North Spring
-
North Spring
The approximate locations of these stations are shown on Figure 1, Groundwater and Surface
Water Sampling Locations. Exceptions to the routine scope of sampling outlined in Table 1 for
this reporting quarter were as follows:
-
No samples were collected at Mid-North Spring on April 30, or at North Spring on
May 22 or June 14, since there was no flow at these locations on these sampling dates.
-
Beginning with the April 30 sampling event (the initial event under the LTGWMP), the
Stout's Creek Downstream station was changed from its previous location at the Hunter
Road culvert to a position just upstream of the confluence of Stout's Creek and the West
Branch of Stout's Creek.
-
Sampling was not performed at monitor wells MW-6I and MW-6D since semi-annual
sampling is specified at these locations.
Sample Collection and Handling
Samples at the spring and stream locations were collected by carefully filling a new disposable
beaker. The water was transferred from the beaker into pre-cleaned amber glass 1-liter bottles
supplied by the analytical laboratory. Routine sampling parameters including temperature and
conductivity were measured and recorded.
Samples were analyzed by Heritage Lab of Indianapolis, Indiana. The samples were analyzed to
a detection limit of 0.1 parts per billion (ppb) for all PCB parameters (except Aroclor 1221;
detection limit 0.5 ppb) by EPA SW-846 method 8082. Samples were also analyzed for total
suspended solids (TSS) by EPA method 160.2.
Oualitv Assurance
For quality assurance purposes a duplicate sample and a field blank were collected during each
sampling event. All environmental and blank samples were labeled and logged onto a chain-of-
custody form. The samples were stored and transported on ice in insulated coolers. Custody of
the water samples was maintained by Viacom until shipment to the analytical laboratory.
Analytical Results for Groundwater Samples
Per the sampling requirements outlined in Table 1, no groundwater (monitor well) samples were
collected during this reporting period. Historical data for the two groundwater sampling stations
specified in the LTGWMP, MW-6I and MW-6D, are reported in Table 2, and Table 3 (Part I)(Part II) & 3-2, respectively
(attached). In addition, historical data for monitor well MW-03 is attached as Table 4, although
this well is not included in the LTGWMP and no further sampling is planned.
Analvtical Results for Surface Water Samples
Field parameter measurements, PCB analytical results, and QA/QC results for surface water
samples collected during this reporting period are reported in Table 5, Table 6, Table 7, Table 8(Part I)/(Part II), Table 9, Table 10, Table 1(Part I)/(Part II)
Each table summarizes historical groundwater monitoring data collected since the completion of
the remedy in November 2000. Table 7 reports historical data for the Stout's Creek West Branch
monitoring station, although this station is not included in the LTGWMP and no further
sampling is planned. Copies of the chain-of-custody forms are provided in Appendix A. Copies
of the certificates of analysis are provided in Appendix B. A validation summary for these
samples appears in Appendix C. Copies of the field sampling data sheets are on file at PSARA's
Bloomington Branch Office.
3.0 CONTINUOUS Flow AND WATER LEVEL MONITORING
The purpose of flow and water level monitoring is to evaluate site-specific data characterizing
site hydrologic response under storm and non-storm conditions, and to evaluate correlations
between PCB concentrations, spring flow and Groundwater elevations.
Scope of Work
The scope of Groundwater level and flow monitoring during this reporting period involved the
use of dedicated instrumentation to record water level and other parameters as summarized in
Table 12.
Water lever transducers, water level data logging equipment, and piezometer crest gauges were
operated during all or part of the period from April 2002 through June 2002 at the following
locations:
Monitoring Location Equipment
Middle SpringIn-Situ mini-Troll transducer/datalogger
Mound SpringIn-Situ mini-Troll transducer/datalogger (4/13-6/30)
MOO-1In-Situ mini-Troll transducer/datalogger (411-4/26)
In-Situ Troll 4000 transducer/datalogger (4/26-6/30)
Icebox QuarryIn-Situ Troll 4000 transducer/datalogger
Wedge QuarryIn-Situ Troll 4000 transducer/datalogger
Stout's CreekIn-Situ mini-Troll transducer/datalogger
Pi ezometer HIn-Situ mini -Troll transducer/datalogger
Middle Spring Crest gauge
Mound Spring Crest gauge
Mid-North Spring Crest gauge
The approximate locations ofthe stations listed in Table 12 are shown on Figure 2, Flow and
Water Level Monitoring Locations.
Flow and Water Level Plots
The following plots for the monitored stations for this reporting period are attached:
-
water level elevation at Stout's Creek Downstream and Piezometer H;
-
water level elevation at Stout's Creek Downstream and Piezometer H;
water elevation and temperature at Icebox Quarry, Wedge Quarry, and MW-01
(elevation only at MW-01 in April);
-
water level elevation at Stout's Creek Downstream and Piezometer H;
flow data for the weirs at Middle Spring and Mound Spring.
Quality Assurance
As a quality assurance check in documenting rain events and changes in flow, rainfall records for
this time period were obtained from the Purdue University State Climatologist's web site
(shadow.agru.purdue.edu/sc.index.htTnl) for the rain gauge station at the Monroe County Airport. This
record was obtained for comparison to the downloaded transducer data at the various monitoring
locations. Raw rainfall data from the web site appears in Appendix D. Rain events of
approximately 0.25- in. or more are indicated on the flow and water level plots. In addition, the
plots for Stout's Creek Downstream also show cumulative rainfall data at the PSARA office rain
gauge, which is the nearest location to the Bennett's Dump site where a continuous rainfall
record is maintained.
As a further data quality check, manual water level measurements were made and crest gauges at
Middle Spring, Mound Spring and Mid-North Sprig were monitored during and after significant
storm events. The purpose of the manual checks and crest gauge monitoring was to verify
instrument readings, in particular those for installations susceptible to the accumulation of silt
and/or algae growth. Manual field check data collected this reporting quarter are shown on the
data plots. Crest gauge measurements appear in Table 13.
A complete instrument maintenance log for all of the Bennett's Dump installations is attached.
This log details the installation, re-indexing, and maintenance histories of each transducer and
data logger present at Bennett's Dump during the 2nd Quarter.
Discussion
Data for this period are complete except as follows:
-
the mini-Troll at Mound Spring was installed on April 13; no data are available prior to
this date;
-
the Troll 4000 at Wedge Quarry malfunctioned from April 1 to April 18, resulting in no
data collected during that time period;
-
the mini-Troll at Stout's Creek Downstream was relocated to a Lemon Lane station for
short-term investigation activities from April 4 to April 13;
-
the mini-Troll installation at Stout's Creek Downstream was damaged during a strong
storm on June S that resulted in the loss of data through June 30.
The malfunction of the mini-Troll at Wedge Quarry during the first half of April was due to an
incorrect initialization time for measurements by the instrument, which was either set incorrectly
or not recognized by the instrument. It cannot be determined whether this was the result of
operator error or a programming fault. However, the instrument began recording data properly
again on April 18 after re-initialization, and continued to do so for the remainder of the reporting
period.
The Stout's Creek Downstream station was damaged during a brief but strong storm on June 5.
A routine post-storm inspection on June 7 revealed that the instrument had been dislodged from
its anchorage and was in the creek tethered to its anchor point by the instrument cable. This
instrument was subsequently reinstalled at the precise same location (index datum) on June 13.
The data collected from that date through the end of the month suggested minor diurnal
fluctuations in creek stage. A second inspection of the instrument cable revealed possible
damage attributable to the June 5 storm event. The cable was returned to the manufacturer for
evaluation and was determined to be beyond repair. The cable was replaced in July and the
instrument appears to have operated reliably since that time.
The foregoing technical problems represent interruptions in the continuous monitoring operation
at these locations. The problems are briefly noted on the flow and water level plots presented
hereafter. In addition however, the plots for Middle Spring and Mound Spring appear to contain
some questionable data. Both instruments record unusually rapid increases and decreases in flow
during the May 7 rain event. The Middle Spring instrument often recorded water level values
that, when converted to flow, were negative or zero during this relatively wet period. No
particular explanation is apparent, although these same fluctuations do not appear in the
subsequent data for June.
Crest Gauges
The crest gauge at Middle Spring was installed on May 2, and the gauge at Mid-North Spring on
June 14. The purpose of the crest gauge at Middle Spring was to provide an additional indication
of maximum flow to help evaluate the extreme fluctuations in flow recorded by the mini-Troll
instrument at this location. The purpose of the crest gauge at Mid-North Spring was to provide
an indication of maximum flow only, since there was no other instrument installed at this
location. As stated previously, monitoring data for these crest gages are presented in Table 13.
Crest gauge readings during the second quarter of 2002 ranged from 0.08-in. to 0.1 8-in. above
the bottom of the V-notch weir at these two locations. These values represent flows ranging from
5.6 to 15.4 gallons per minute (gpm), as shown in Table 13. In general, the crest gauge data for
Middle Spring compare favorably (within 17%, on average) with the maximum transducer value
recorded at this location for the same time periods. In several cases, however, the transducer at
Middle Spring recorded extreme high and low (below zero) values that were viewed as
unreasonable. These relatively extreme conditions occurred on May 2, May 7, May 18 through
25, and June 13. For these dates the mini-troll data were compared to the crest gauge data in an
attempt to validate or discount the data extremes recorded by the mini-Troll. In all cases, the
crest gauge data, which is an upper limit value, was substantially less than the data from the
mini-Troll. For this reason, the mini-Troll data for these dates was regarded as suspect and was
removed from the attached flow plots for Middle Spring. The reason for the periodic erratic
behavior of the mini-Troll at Middle Spring has not been established at this time.
Potentiometric Data
On April 29, 2002, water levels were measured by hand at 5 monitor wells, 2 quarries and 4
springs at the site. The specific measurement locations are listed in the table insert on Figure 3,
which also depicts the resulting potentiometric surface across the site on this date.
|
