Method

1. Grade

Grade is rise over run, as a percent: grade % = (rise ÷ run) × 100. One percent means the ground falls 1 foot across 100 feet. A 4-foot level reads level when a 1% grade drops its downhill end by 0.48 inches — the thickness of a half-inch shim. We write grade as percent everywhere, never as ratio (20:1), because percent is what codes and inspectors use.

2. Percolation rate

Perk rate is inches of water level that drop per hour, from a single presoaked hole — the method in the perk test job. We report it as one number from one representative hole, and we say which hole. A yard is not a rate; one test hole is not a yard. That is a limitation the desk repeats on purpose.

3. Catchment

Catchment is square footage of impervious surface (roof planes, driveways, walks) plus the uphill yard area that visibly drains toward the wet spot — the counting rules in the catchment object. We use the plan-view footprint, not the pitched roof area, and we say so, because vendors often use the larger number.

4. Codes

Code figures (minimum grade, setback distances, drawdown limits) are always labeled as coming from a named code or stormwater manual, with a link. Codes differ between cities; a national number on a drainage page is a red flag. When we state a common range, we give the range, not a fake single value.

5. The stamp

Each page carries a checked date. Object and job pages are re-checked against their sources on that date. Note pages carry their writing date and a "rots" warning when the topic can decay. A stale stamp means the page has not been revisited, and the page says so.