Passive
A compacted earth mound set upslope of the house with its apex pointing uphill, so a surge of water, mud or debris is split and passes down either flank rather than striking the wall. It deflects rather than stops. Built in concrete or stone instead of earth, the same idea is called a deflection wall.
One of 3 ways to meet Flood mitigation. Build 2/3, Upkeep 2/3, Efficiency not rated. Cost, carbon and footprint below are rated against those 3, not in absolute terms.
Sloping ground with room upslope for the mound and a clear run for the deflected flow down both sides. Against a real debris or mudflow hazard this is a life-safety structure: its height, angle and siting are an engineer’s job, not a judgement from the catalogue, and a badly placed one moves the hazard onto someone else.
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Every option in this sub-function, with the value on each axis and a note on what drives it (this solution highlighted):
| Solution | Build skill | Upkeep burden | Efficiency |
|---|---|---|---|
| Elevated finished floor level | N/A | 0 | N/A |
| Diversion swale / intercept ditch | Basic | 3 | N/A |
| Deflection berm (splitter wedge) | Intermediate | 2 | N/A |
Build skill and upkeep burden are proxies (lower burden = simpler to maintain); the efficiency column is this sub-function’s ranking, 1 = best. “N/A” where an axis isn’t rated here.
No build tutorial recorded yet.
No sizing or quantities: how much a technique yields, and how much a household needs, both depend on the build and the people, so the catalogue compares options rather than dimensioning them. It carries no bill of materials and no build sequence, and it is written for an oceanic, clay-soil climate (Normandy, France). Regulatory notes are indicative and need confirming locally.