The Overflowing Washout and the As-Built Orifice
You're reviewing a site that is about 85 percent complete. The concrete washout is a lined pit, but it is full to within 6 inches of the top and the liner is torn at one corner. A ready-mix driver is rinsing his chute into it, and the overflow runs across bare ground toward a drop inlet 30 feet away. Nearby, four rolls of geotextile sit on bare ground and a 275-gallon fuel cube has no secondary containment and a sheen beneath it. The inspection log shows the last three inspections at 12, 15, and 19 days apart with no rain in between; the SWPPP requires weekly. The permanent detention basin as built is 0.6 foot shallower than the plan and the low-flow orifice is 4 inches instead of the designed 3.
1. What are your immediate priorities on arrival, and what do you do about the driver?
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In order:
- Stop the active discharge. Ask the driver to stop rinsing - immediately, not after he finishes the load. He is not the decision-maker, but he is the person with his hand on the chute.
- Break the path to the inlet. Straw bales, a berm, or a temporary diversion across the 30-foot run before the next rinse. A drop inlet 30 feet away is a direct route to the storm system.
- Get the pit pumped out and the liner repaired or replaced. A washout at 6 inches from overflow has no capacity. Schedule pump-out so it happens before the next pour, not after the next overflow.
- The fuel cube. Absorbents on the sheen, contain the area, and get secondary containment under it the same day. A sheen under a 275-gallon cube near bare ground and a drop inlet is the higher-consequence item on the site.
- Material storage. Geotextile on bare ground is a lesser finding - it degrades and collects mud - but it's cheap to fix with pallets.
Document: the rinse occurring, the overflow path, the distance to the inlet, and the sheen, with photos and a written notification to the operator the same day.
2. The inspections were 12, 15, and 19 days apart with no rain in between. How do you weigh this - is it a violation, and how significant?
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It is a noncompliance; the judgment is about how you report and escalate it, not about whether it counts.
The inspection interval is a requirement independent of weather. The purpose is to catch a problem - a torn liner, a plugged riser, a failed fence - before the storm that turns it into a discharge. Missed intervals mean the site ran unobserved, and the fact that no rain fell reduces the impact but doesn't restore the lost inspection.
Weighing it:
- The pattern is worsening (12 → 15 → 19), which reads as drift rather than a one-off.
- No rain in the gaps limits the environmental consequence but not the record deficiency.
- The site's other findings - overflowing washout, torn liner, uncontained fuel - are exactly the kind of conditions those missed inspections should have caught. That connection is what makes it significant rather than clerical.
Action: record the three intervals with dates, cite the SWPPP requirement, notify the operator in writing, and require a return to the stated frequency with documentation. Do not soften it to "administrative" - the condition of the washout is the evidence of what unobserved weeks produce.
3. How do you handle the as-built basin deviation - 0.6 foot shallower and a 4-inch orifice instead of 3-inch - as the project moves toward closeout?
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Neither number is yours to accept or waive.
Why it matters functionally:
- A larger orifice drains the basin faster, shortening detention time and reducing settling of the particles the basin was designed to remove - the basin passes sediment downstream that it was sized to capture.
- A shallower basin reduces storage volume, so the design storm fills it sooner and the extra water goes out the emergency spillway or bypasses treatment.
- The two deviations compound: less storage, faster release.
What you do:
- Document both dimensions with measurements, photos, and a comparison to the approved plan sheet.
- Flag it to the permittee and require review by the design engineer, with either a corrected as-built or a sealed justification showing the basin still meets the design criteria.
- Record it as open before final stabilization and before any notice-of-termination step. Closeout is the last point at which this is fixable cheaply.
- Keep the distinction clear in the report: your finding is the measurement and the discrepancy; the acceptability determination belongs to the engineer and the reviewing authority. Say that explicitly so the record shows who decided what.