| |||||
|
STORMWATER DISCHARGE ABOVE THE PERFORMANCE STANDARD - MARCH 14, 2010 As required when significant rain events occur, on March 14, 2010, AGC personnel conducted an Erosion and Sedimentation Control Inspection at the Marjol Site. The water in the basin and the discharge from the basin was turbid. A turbidity reading was taken for the water being discharged. (Click here for Stormwater Sampling and Discharge information). The water was found to have a sediment load well above the performance standard: 1275 NTUs when it is supposed to be below 250 NTUs. AGC pulled the skimmer to stop discharge from the basin. SCE was called to the Site and applied Pond Clear in the basin and the discharge channel (to cause the sediments to drop out of the water). A leak was found in the outlet structure so water was still able to discharge but at a much slower rate and at a much decreased volume. After the Pond Clear was added, the discharge turbidity dropped to 205 NTUs. The high flows of water in the discharge channel had blown out the silt fence and silt socks at the fence line, so SCE also placed additional silt socks outside the fence in a U-shape. When AGC left the Site on March 14, 2010, the turbidity levels in the discharge channel had dropped to 195 NTUs. Water samples (one for total lead and one for dissolved lead) were collected from the discharge point and were sent to the laboratory for analysis. Dissolved lead was not detected at a detection limit of 1 ug/L. The NPDES permit standard for maximum dissolved lead for the Site is 650 ug/L. The total lead result is 18.2 ug/L. There is not an NPDES standard for total lead. The very low total and dissolved lead results provide reassurance that even though the turbidity levels were above the performance standard, there was NOT a release of lead from the site that would affect the creek or the river. SCE worked on March 15 and 16, 2010 to repair the leak in the outlet structure. Once the outlet structure was repaired, the discharge channel was allowed to drain and then repairs were made to the silt fence and silt socks. Hay bales were also placed on March 15, 2010. A turbidity reading was collected at the discharge point on March 15, 2010; the result was 223 NTUs. USEPA, PADEP, and Throop Borough were notified of the situation on March 15, 2010. Lackawanna County Conservation District was also notified. As is required, a non-compliance report was submitted to PADEP on March 19, 2010. (Click here to review the March 14, 2010 Non-Compliance Report.) The skimmer was lowered back down on March 16, 2010 to allow water from the basin to drain as it is designed to do. Turbidity readings after the skimmer was lowered were as follows: 11:30 am - 124 NTUs 11:40 am - 71.8 NTUs |
|