Lagoon From the drawings

Base Length m

Base Width m

Depth, Base to Crest m

Side Slope (Horizontal per 1 Vertical) H:1

Two means two metres across for every metre down.

Sheet From the cover and liner design

Run-Out into the Anchor Trench, Each Side m

Sheet carried over the crest and into the trench that holds it.

Cover Slack %

Extra cover so it can rise and fall with the level and gather gas.

Floating Cover Area

— m²

Top area plus the run-out round the perimeter, plus slack

Geometry

Top Length: — m
Top Width: — m
Area at the Crest: — m²
Slope Length, Base to Crest: — m
Liner Area incl. Run-Out: — m²
Anchor Trench Length: — m
Volume to the Crest: — m³

The lagoon is a rectangular base with four sides at the same slope, so the top is the base plus twice the horizontal run of a side. Cover and liner both run over the crest into an anchor trench round the top; the run-out, slack and the trench detail are the design's. Liner area is the base plus four trapezoidal sides measured along the slope. Volume is to the crest, by the prismoidal formula, which is exact for this shape; working volume is less by the freeboard. Welding overlaps and the trench itself are not counted. **This is a geometry take-off; cover ballast, gas handling and liner leak detection are design matters.**

Lagoon & Pond Geometry: Floating Cover Area, Liner Area, Volume & Anchor Trench Length — free, with the formula and a worked example, at Textile School.