The 7'6" Trench and the Storm Drain

Stop, clear, secure - in that order, before any conversation about schedule.

1. Order the crew out of the trench and stop the loader. Do it yourself, verbally and loudly, then document it. A worker in a 7'6" vertical Type C cut with an unshored crossing water main is a fatality scenario, not a compliance finding. Nothing on the site is worth ten more minutes in that hole.
2. Suspend the excavation work by written stop-work notice to the subcontractor, delivered the same morning, stating the specific conditions and the standard. A verbal stop will be argued about later; a written one will not.
3. Fence or barricade the excavation so nobody - including your own crew or the public if the property line abuts a walk - can fall in. Move the loader well back.
4. Notify up the chain: your project manager, the owner, the general contractor's safety officer, and the subcontractor's principal - not just the foreman.
5. Get the water main located and protected. Call the utility owner and the locating service. An unshored 12-inch main crossing the trench bottom is a supply interruption and a flooding/inundation hazard; the utility may require shoring or a protective bridge.
6. Designate a competent person - trained, experienced, with authority to stop work - and have them inspect and log before anyone re-enters.

The judgment point: "we'll be done by noon" is the single most common sentence preceding a trench fatality. Duration is irrelevant; the exposure exists at the first minute and the hazard is not reduced by the crew being fast.

Deficiencies observed:

• No protective system at 7'6". A protective system is required for excavations 5 feet or deeper (and for shallower excavations where the competent person identifies a hazard).
• Vertical cut in Type C soil. Type C soil will not stand vertically; the maximum allowable slope is 1½:1 (horizontal:vertical, about 34 degrees). A vertical face is a slope failure waiting for the first rain or vibration.
• Spoil 18 inches from the lip. Spoil and equipment must be kept at least 2 feet back from the edge - and further where the soil is Type C or the surcharge is heavy.
• Loader operating 8 feet from the lip. Equipment vibration and surcharge load the crest and are a recognized cause of collapse. Push it back well beyond the influence zone or provide a shored/engineered system designed for the surcharge.
• No competent person. Required, with daily inspections before each shift and after rain or any event that could affect stability.
• Means of egress. For a trench 4 feet or deeper, a ladder or ramp is required within 25 feet of lateral travel for every worker.
• Utilities not protected. The crossing main must be supported and the excavation around it hand-dug and shored.
• Water. Groundwater and surface water must be controlled; the pump indicates water in the cut, which further destabilizes Type C material.

Compliant options: slope the sides to 1½:1 (requires right-of-way room you may not have along a property line), or install a trench shield/box, or shoring designed for Type C with the actual depth and surcharge. Given the property line, a shield or shoring is the realistic answer - and it needs to be sized by a competent person or engineer, not by what's on the truck.

The practice is almost certainly a violation, and it is the kind that generates penalties and public complaints.

Why: discharging sediment-laden groundwater to a municipal separate storm sewer system is a point-source discharge to waters of the United States unless covered by a permit. The construction general permit covers stormwater from the site, not pumped groundwater from an excavation, which typically requires a separate dewatering authorization. Local pretreatment rules may also prohibit it outright.

What goes wrong: turbidity and sediment plumes, a fish kill or visible discharge complaint, an NOV, and a citizen suit. Fines are per-day. On a steel project, the dewatering flow can be substantial and continuous, which makes it the most visible violation on the site.

Compliant path, in sequence:

1. Stop the discharge today and report it internally and, if your permit requires it, to the authority. Voluntary disclosure on day two is handled far better than discovery on day twenty.
2. Characterize the water: flow rate, pH, turbidity, and whether it is contaminated (dewatering near a former gas station or a fuel oil tank is a different problem entirely - that can make it a hazardous waste issue).
3. Treat before discharge: a sediment basin or tank, filter bags, or a weir; adjust pH if it is outside the permitted range. Sample and keep logs.
4. Get the authorization: check the site's SWPPP and whether a separate dewatering permit is required; route to sanitary sewer under a local industrial discharge permit if that is the allowed path, with metering and sampling.
5. Amend the SWPPP and train the crew. The pump operator needs to know where the hose is allowed to go; the default of "nearest drain" is what creates these events.

Judgment: the cost of a filter bag and a settling tank is trivial against a single enforcement action, and it takes an afternoon to set up. Treat it as a now-problem, not a paperwork problem.