| Marjol Battery Site |
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Stormwater Management System
In order to control stormwater at the Site both during and after construction
activities and to keep sediment (small soil particles that are carried along in
water) on the Site and out of the Lackawanna River, a basin and other drainage
features such as check dams and swales were constructed as outlined in the USEPA/PADEP-approved
100% Design Plan for the Site (Click here for more information on the
Final 100% Remedial Design Plan). The stormwater management system consists
of several items
STORMWATER
SAMPLING AND DISCHARGE
The 100% Design Plan calls
for stormwater from the clean areas of the Site to be collected in the new
temporary sediment basin. Sediment that is carried along with the stormwater
settles out in the basin, and stormwater collected in the basin is released to
Sulphur Creek under a permit issued by the State of Pennsylvania. During
construction of the Final Remedy at the Site, the drainage system is designed so
stormwater falling on contaminated areas of the Site does not flow into the
basin, but is retained within the contaminated areas by berms. If there is not enough space
for all of the water to be held within the contaminated areas, however, the
design provides for the potentially contaminated water to also drain to the
sediment basin. Since lead sticks to the sediment, as long as the sediment is
kept on the site by allowing it to settle out of the water in the basin, the
water can be safely discharged to the river. This sediment can then be easily
excavated and placed into the Containment Area before the final cap is
installed. In this way, the water is managed so that the lead remains on the
site by controlling where the sediment goes. Sampling of the basin
discharge is included in the 100% Design Plan and became part of the state
permit. The design requires stormwater from the basin to be sampled as it is
being discharged into Sulphur Creek until the areas draining to the basin have
grass growing on them. The basin stormwater sampling plan consists of the
following: If the skimmer has been raised so that it does not
discharge water (for example, if there is a concern that contaminants
may have entered the basin), then the basin water is checked to see if
the turbidity is above the performance standard of 250 NTUs. If it is
above 250 NTUs, then a flocculant (i.e. Pond Clear) is added to the
water to get the soil particles to drop to the bottom leaving clear
water at the surface. Once the turbidity is below 250 NTUs, the skimmer
is lowered and the basin water discharges through the skimmer.
(Click here for a picture
of the skimmer in the discharge position.) CONTAINMENT (CAP) AREA OVERFLOWS As a result of heavy rains in July and August, 2009, water overflowed the Containment (cap) Area (CA) (which has contaminated material in it) into a drainage feature (the South Swale) outside of the CA and into the basin on July 31, August 10, and on August 12, 2009. While every effort has been made to keep this type of overflow from occurring, the possibility of it happening was considered in the design, and so the overflow water flowed into the sediment basin as it is supposed to do where the lead contaminated sediment could settle out before the water is discharged. Tests conducted after the overflows show that the discharges were well below the limits that were set by the State to protect the Lackawanna River. When each of the overflow incidents has occurred, the skimmer in the basin has been raised (if it wasn’t already) to prevent the flow of water from the basin through the discharge channel. Water in the basin was tested for turbidity and when it was below the performance standard, the skimmer was lowered to allow water to discharge. After the overflow in July, the basin water was also tested for total and dissolved lead. Any sediment and battery casings that have floated onto the CA berm and into the swale were removed and placed back into the CA. XRF analysis (an XRF is a portable instrument used for testing lead concentration in substances such as soil) for lead has been performed on the berm and in the swale to see if the overflow contaminated any previously clean areas. If the soil lead levels were above the cleanup level, then soils on the berm and swale were excavated and placed into the CA. The excavated areas were rechecked with the XRF to be sure lead levels were below the cleanup standard. After the
first overflow, a meeting was held to discuss how to better control an overflow
if it happened again. In order to get more room to hold the contaminated water
so that it would not go off-site, it was decided to pump the contaminated water
from the CA to a strip pit that was previously excavated – Area B – instead of
back into the CA as the practice had been. Area B will be tested near the end of
the project and will be re-excavated if necessary with any contaminated material
being placed in the CA and solidified. Subsequent efforts after the overflows
focused on making sure that the pumps were ready when rain occurred during the
night and that the pumps could handle all of the water. While the overflows are
not what we would like to see, the important point is that the lead is being
contained within the site as it is supposed to be while we are managing the
water as best we can with the unfavorable weather we have been having. Daily Stormwater and Sediment Data and Information – September 2009 Click on the shaded dates (the numbers) below to view turbidity data, stormwater discharge data and XRF sediment testing data available for those days. (Note: Turbidity data is only collected on days when the basin is discharging or following an overflow of the Containment Area. Collection of samples of stormwater discharge for laboratory analysis is required monthly and has also been performed when overflows have occurred. Sediment sampling has taken place when overflows have occurred.) No testing was performed and therefore no data are available for the dates that are not shaded. Incidents such as the Containment Area (CA) Overflow are noted on the calendar. Copies of the reports regarding the overflows are provided on the calendar pages for those dates. Note: In September 2009, water was only flowing in the discharge channel on one day, September 12, 2009, but there was not enough water to collect samples on that date.
Page Last Modified Tuesday October 13, 2009 01:33:46 PM
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