State of Oregon Department of Environmental Quality

Transcription

1 State of Oregon Department of Environmental Quality Industrial Stormwater Advisory Committee Meeting 8- April 20, 200 Jenine Camilleri, Stormwater Coordinator and Doug Drake, Lower Willamette Basin Coordinator, Water Quality Division Subject: Discharges to Columbia Slough Watershed Background: At the 7 th advisory committee meeting in February, DEQ discussed with the committee the new requirements for discharges to impaired waterbodies with TMDLS. DEQ recommended that the agency will presume that compliance with the permit will meet the requirements of the majority of the Total Maximum Daily Load (TMDLs) in the state. The Columbia Slough TMDL specifically identifies that reductions are needed from industrial. DEQ further evaluated the TMDL to determine whether additional requirements for the industrial sources within the basin are necessary to ensure compliance with the TMDL. The table below summarizes DEQ s review of the Columbia Slough TMDL and includes the benchmark parameters in the 200-COLS permit and the impairment pollutants on the 303(d) list for the Columbia Slough Watershed. The only benchmark in the permit that has an explicit Waste Load Allocation (WLA) described in the TMDL is Biological Oxygen Demand (BOD). The other benchmarks addressed in the TMDL (lead, TSS, E.coli, and phosphorus) were given broad s often under the term, which makes it difficult to link a specific industrial benchmark to a WLA. The TMDL strategy for industrial is a general approach in which facilities will implement Best Management Practices (BMPs) and monitor the effectiveness of these controls via the benchmarks. DEQ believes that BMPs and benchmarks are still the best approach to meet the goals of the TMDL. Benchmark Addressed in TMDL Explicit WLA in TMDL for Industrial Stormwater? Basis for benchmark concentrations BOD Yes 33 mg/l based on reduction of industrial loading to meet TMDL WLA E.coli Lead 406 counts per 00 ml based on water quality standard 0.06 mg/l based on acute criteria mean 5% 8% 3% Percentages are based on Discharge Monitoring Report data from the past three monitoring years. These are only estimates since facilities will submit the mean evaluation in July 200.

2 Benchmark Addressed in TMDL Phosphorus TSS 3 Explicit WLA in TMDL for Industrial Stormwater? Basis for benchmark concentrations 0.6 mg/l based background levels in slough 50 mg/l based technology assessment mean 2 46% 36% Other Benchmark Zinc Basis for benchmark concentrations mean 0.24 mg/l based on acute water quality standard and 23% dilution of rate of 2 4 Copper mg/l based on acute water quality standard and dilution of rate of 2 6% ph S.U. based on natural conditions of rainwater Have not conducted this analysis Oil and Grease 0 mg/l based on technology assessment 6% Impairment Needing TMDLs Iron Toxics Criteria Quantitation Limit Note Fresh water chronic aquatic life criteria 000 ug/l 00 ug/l Manganese Human Health: water and org. 50 mg/l; fish consumption only 00 ug/l 2 ug/l DEQ is proposing to withdraw HH criteria for consumption of water and aquatic organisms. HH criteria for fish consumption will apply to marine waters. DEQ is proposing that facilities will not be required to monitor for this pollutant under new permits unless they discharge to marine waters. 2 Percentages are based on Discharge Monitoring Report data from the past three monitoring years. These are only estimates since facilities will submit the mean evaluation in July TSS is surrogate for organic pollutants (DDE/DDT, PCBs, Dieldrin and Dioxin). 4 Dilution rate of 2 is based on TMDL assessment of dilution in Columbia Slough Watershed. 2

3 Recommended approach for additional requirements for discharges to Columbia Slough Watershed: BOD: Because the TMDL identified a WLA for industrial for BOD, DEQ evaluated whether additional requirements are necessary to meet the goals and intent of the TMDL. DEQ considered the following options: Requiring facilities to obtain an individual permit. Requiring numeric effluent limits in the general permit. However, the TMDL specifically states that the WLA for BOD will not be incorporated into industrial general permit as a numeric effluent limit. Requiring facilities implement additional BMPs to address the pollutant(s) of concern in the general permit. To meet the WLA in the TMDL for BOD, DEQ believes that additional requirements are necessary to ensure that facilities are installing effective BMPs to further reduce BOD concentrations in discharges to the Columbia Slough Watershed. DEQ is recommending that facilities that have not met the BOD benchmark, based on the 4 th year geometric mean evaluation under the current permit, implement additional BMPs to reduce the BOD concentrations in their discharge to levels at or below the benchmark. 5 Based on existing data from the past three monitoring years, approximately 5% of the facilities are exceeding the BOD benchmark. TSS: TSS is of particular interest to DEQ. The TMDL identified TSS as a key surrogate for the organic toxics (DDT/DDE, dieldrin, PCBs, and dioxin) and lead. The TMDL requires that facilities ensure that the BMPs that they install are effectively controlling TSS. However, based on existing data from the past three monitoring years, approximately 36% of the facilities are exceeding the TSS benchmark. Given that the benchmark was based on a technology assessment, there are BMPs available that are economically and technologically feasible to address TSS. DEQ will continue to emphasize that facilities install effective BMPs to address TSS. To meet the intent and goals of the TMDL, DEQ believes that additional requirements are necessary to ensure that facilities are installing effective BMPs to address high concentrations of TSS in their discharge. DEQ is recommending that facilities that have not met the TSS benchmark, based on the mean evaluation under the current permit, implement additional BMPs to reduce the TSS concentration in their discharge to levels at or below the benchmark. 6 DEQ conducted a preliminary evaluation of the data related to TSS based on a simple graphical analysis (please see figures below). The goal of this analysis was to determine whether or not there is any relationship between TSS and the other TMDL benchmark parameters. Based on this analysis, DEQ found that reducing TSS in discharges via BMPs is an appropriate strategy for reducing the other TMDL benchmark parameters (e.g., lead and phosphorus). 5 There is not a water quality standard for BOD. DEQ will use the current benchmark concentration of 33 mg/l. 6 There is not a water quality standard for TSS. DEQ will use the current benchmark concentration of 50 mg/l. 3

4 TSS (mg/l) TSS (mg/l) TSS & Lead 0000 R² = Lead (mg/l) Figure Correlation between TSS and Lead is moderate (Pearson R 2 = 0.405). The red lines are the benchmarks for each (TSS = 50 mg/l and Lead = 0.06 mg/l). The graph illustrates that when a sample meets the TSS benchmark (lower left box) it also, more often than not, meets the Lead benchmark (lower right box). 0. TSS & TP 0000 R² = Total Phosphorus (mg/l) Figure 2 The correlation between TSS and Total Phosphorus is slightly better than Lead (Pearson R 2 = 0.49), but again shows that there is a relationship. The red lines are the benchmarks for each (TSS = 50 mg/l and TP = 0.6 mg/l). As with Lead the graph illustrates that when a sample meets the TSS benchmark (lower left box) it also, more often than not, meets the Phosphorus benchmark (lower right box). 4

5 Recommended BMP and Monitoring Requirements: Facilities that have not met the BOD and TSS benchmarks, based on the mean evaluation under the current permit, must meet the following requirements under the new permit: Conduct a comprehensive review of BMPs to address the pollutant of concern. Select the most effective BMPs proven to reduce the pollutant concentrations in the discharge to levels at or below the benchmark. Facilities may not consider economic constraints as a basis for selecting a less effective BMPs. In the Stormwater Pollution Control Plan submitted as part of the renewal application to obtain coverage under the new permit, identify the specific BMPs that will be implemented, the anticipated BMP effluent concentrations, and the implementation schedule that includes the date the BMPs will be initiated and completed. DEQ will review this information for completeness, but will not verify the efficacy of the BMPs. DEQ is considering requiring facilities to have this portion of the plan stamped by a licensed professional engineer, certified engineering geologist, hydrogeologist, or certified professional in quality. Conduct composite grab samples 4 times per year to ensure that the BMPs are working effectively. If monitoring results are above the benchmarks, within 4 days of receiving monitoring data, facilities must investigate the cause of the elevated pollutant levels, the reason the BMPs are not working effectively and determine the appropriate corrective actions. Facilities must document in their annual report the corrective actions taken. If after taking these corrective actions, subsequent monitoring results establish that the BMPs are not effective at reducing the pollutants concentrations in the discharge (i.e., spikes of high pollutant concentrations or a pattern of concentrations above the benchmark), DEQ can require facilities to obtain an individual permit. 5