GAR050000
General Storm Water Permit
for Industrial Activity
Status of the
Construction Aggregates Industry
General Permit No.GAR050000
• Authorization to Discharge Under the
National Pollutant Discharge Elimination System
• Storm Water Discharges Associated with Industrial
Activity
• Replaces General Permit No. GAR000000
• Approximately 100 quarries/mines, 220 concrete plants,
and 60 asphalt plants have applied for coverage
General Permit No.GAR050000
• So what has changed?
-The Permit’s format has been revised to be organized
similar to EPA’s 2008 Multi-Sector General Permit
(MSGP).
-There are new sector specific requirements,
benchmarks, and best management practices (BMPs)
-Smoke/Dye Testing are required at least once during
the permit period. All drains including floor drains and
sinks in industrial areas must be tested and
documented in the Annual Report.
General Permit No.GAR050000
• So what has changed?
-There are new SWPPP requirements and a
corresponding checklist that must be submitted with the
Annual Report.
-There are new requirements for the SWPPP site map.
- SWPPPs are required to specifically address vehicle
and equipment washing as any discharge associated
with these operations are not authorized and may
require a separate permit.
General Permit No.GAR050000
• So what has changed?
-All employees working within areas where industrial
materials or activities are exposed to storm water must
be trained. EPD’s recommendation is training at time of
hire and retrained at least annually.
-Rosters and training dates are required to be
maintained within the SWPPP or be readily available
onsite.
General Permit No.GAR050000
• In effect since June 1, 2012
• Monitoring requirements started during the first full
quarter following the effective date
– July 1 until September 30
• The next quarter ran from October 1 until December 31,
2012
• Two quarters have passed, and we’re in the third. . .
where are we as an industry?
General Permit No.GAR050000
• Statistics of GCAA Member Sites (Crushed Stone):
– No. of Sites Covered Under IGP – 58
– No. of SW Outfalls – 146
• Average of about 2.5 per site
– No. of SW Outfalls with No Discharge – 84
• About 58% have not discharged
– No. of Benchmark Samples Collected – 107
– No. of Samples Over Benchmark – 21
• About 20%
– No. of Dye/Smoke Tests Completed - 0
General Permit No.GAR050000
Review of Monitoring
Requirements
General Permit No.GAR050000
• Quarterly Visual Assessments
– Same as under previous permit
• Benchmark
– Annual
– Discharges from material storage piles
• Impaired Streams
General Permit No.GAR050000
• Measurable storm event:
– Greater than 0.1” of rain that results in an actual discharge
from the facility
– Follows the preceding measurable storm event by at least
72 hours
• Sample Type
– Samples are to be collected within first 30 minutes of
discharge (or as soon as practical with documentation
maintained in SWPPP of why it was not possible to collect
during initial 30 minutes.)
– During normal operating hours
General Permit No.GAR050000
• Quarterly Visual Assessment
– Once per quarter for entire term of permit
– Visually inspect for: color, odor, turbidity, floating solids,
settled solids, suspended solids, foam, oil sheen, and
other indicators of storm water pollution.
– Document results, perform and document corrective
actions as indicated by results according to the schedule in
the IGP.
General Permit No.GAR050000
• Benchmark Monitoring
– Requires laboratory analysis of the sample.
– Benchmarks serve as “levels of concern” for storm water
sampling.
– Benchmarks are not permit limits, therefore an
exceedance is not a permit violation.
– Primarily for permittee’s use to determine the overall
effectiveness of the control measures and to determine if
corrective actions are needed.
General Permit No.GAR050000
• However, when a benchmark is exceeded, the permittee
must:
- Review the control measures, make necessary
modifications, and document according to schedule in
IGP.
- Continue to sample each quarter until the benchmark is
met or it is determined that no further pollutant reduction
is feasible . . .
- Notify EPD of your determination in the annual report
General Permit No.GAR050000
• Impaired Streams Monitoring
– Definition: A stream with chronic or recurring monitored
violations of the applicable numeric and/or narrative water
quality criteria.
– Applicable to discharge into or within one linear mile
upstream of, and in the same watershed as, any portion of
an impaired stream segment
– Twice per quarter for first year of permit.
• If 75% or the average pass the benchmark value, then annual
monitoring.
• If not, select and implement additional BMPs (up to one year)
• Re evaluate by twice per quarter sampling for additional year
General Permit No.GAR050000
• Benchmark Monitoring
– Case study #1: Details
• Storm water outfall from overburden area, roadway,
and stockpile area
• Overburden area mostly stabilized with vegetation
• Sediment pond mostly reclaimed
• Pipe under road carries runoff from small depression
beside road and stockpile area into sediment pond
• 191 mg/L TSS
Case Study #1
overburden
road
stockpiles
road
sediment
pond
pipe
SW outfall
creek
General Permit No.GAR050000
• Benchmark Monitoring
– Case study #1: Corrective Actions
• Pipe under road was fitted with elbow to turn
depression into a basin
• Discharge pipe was wrapped with filter cloth and
surrounded with W57s to filter sediment before
discharge
Case Study #1
overburden
road
stockpiles
road
Elbow
on pipe
sediment
pond
SW outfall
creek
Case Study #1
Case Study #1
General Permit No.GAR050000
• Benchmark Monitoring
– Case study #1:
• 7 mg/L TSS after corrective actions
General Permit No.GAR050000
• Benchmark Monitoring
– Case study #2: Details
• Storm water from roadway to on-site customers
• Catch basins / filter berms along ditch line
• Runoff entered ditch at lowest point – just before
discharge through pipe
• 438 mg/L TSS
Case Study #2
creek
road
catch
basins /
filter
berms
customer sites
creek
General Permit No.GAR050000
• Benchmark Monitoring
– Case study #2: Corrective Actions
• Catch basins / filter berms were cleaned out
• Runoff was diverted into ditch in selected locations
• Fresh filter stone was placed around pipe
• Riprap plunge pool / sediment basin was installed at
end of pipe – sample collected before creek
Case Study #2
Case Study #2
Case Study #2
General Permit No.GAR050000
• Benchmark Monitoring
– Case study #2:
• 24 mg/L TSS after corrective actions
General Permit No.GAR050000
• Benchmark Monitoring
– Case study #3: Details
• Storm water from overburden and stockpile area
adjacent to on-site customer
• Slopes were vegetated until new materials was stocked
• Discharge pipe installed with large holes in it
• 592 mg/L TSS
Case Study #3
storm water pond
creek
road
overburden and
stockpile storage
catch
customer site
basins /
filter
berms
creek
General Permit No.GAR050000
• Benchmark Monitoring
– Case study #3: Corrective Actions
• Filter berms were installed in pond on either side of
discharge pipe
• Fresh filter stone was placed around pipe
Case Study #3
filter berms
storm water pond
General Permit No.GAR050000
• Benchmark Monitoring
– Case study #3:
• 9 mg/L TSS after corrective actions
General Permit No.GAR050000
• Benchmark Monitoring
– Case study #4: Details
• Storm water from roadway and stockpile area next to a
scale house
• Adjacent to a creek buffer
• 418 mg/L TSS
Case Study #4
roadway
creek
road
scale house
catch
basins /
filter
berms
creek
stockpiles
creek
General Permit No.GAR050000
• Benchmark Monitoring
– Case study #4: Corrective Actions
• Installed filter berm around discharge
Case Study #4
filter berms
storm water pond
General Permit No.GAR050000
• Benchmark Monitoring
– Case study #4:
• No discharge from outfall since corrective actions
were taken.
General Permit No.GAR050000
• “No Discharge”
– 1) No rainfall events that met definition of “measurable”
– 2) At least 72 hours since last measurable rain event
– 3) During normal working hours
– 4) That results in an actual discharge from the site.
General Permit No.GAR050000
• Monitoring Exemptions
– “Substantially identical outfall” (if not discharging to
imparted stream) may monitor just one outfall and report
that results apply to the others as long as:
• Identified in storm water pollution prevention plan (SWPPP)
with rationale for determination
• Similar industrial activities and control measures, exposed
materials, and runoff coefficients of drainage basins.
– Inactive and Unstaffed Sites
• Maintain a statement onsite with SWPPP stating the site is
inactive and unstaffed
• Begin benchmark monitoring as in first year if facility
becomes active and/or staffed
General Permit No.GAR050000
• Monitoring Documentation
– For each monitoring event:
• Date and duration of the rainfall event
• Rainfall total (in inches)
• Time (in days) since previous measurable storm event or the
absence of measurable precipitation in the 72 hours
preceding the monitoring event
• Estimated volume (in gallons) of the discharge sampled
• Recordkeeping
– SWPPP, monitoring results, corrective actions, reports and other
support info must be maintained for at least 3 years after
expiration of permit.
General Permit No.GAR050000
Questions?