Theory 01/Coastal Engineering
Nourishment Lifespan Is a Grain Ratio
The claim
Beach nourishment longevity is set by the ratio of fill grain size to native sediment size rather than by fill volume, so a larger volume of fine sand can disappear faster than a smaller volume of coarse sand.
01Mechanism
Fill that is finer than the native beach is transported offshore by the same waves that leave coarser material in place; the ratio determines whether the fill stays in the active profile.
02Predictions
- P1Lifespan should track the grain-size ratio.
- P2Volume alone should mispredict across sediment types.
03Refutation
Lifespan tracking volume at controlled grain size would remove the ratio.