The bay’s dramatic tidal amplitude (up to ~14–15 m during equinox springs) transforms access and ecology daily.

1. Tide Mechanics Simplified

Term	Meaning	Visitor Relevance
Spring Tide	Higher amplitude (moon + sun aligned)	Island isolation peak photography
Neap Tide	Lower amplitude	Extended mudflat exposure
Bore / Rapid Inrush	Fast moving front during certain springs	Bay crossing timing caution

Check official tide tables; misjudging speed risks entrapment in rising channels.

2. Sedimentation & Hydraulic Management

Historic diking & parking embankments promoted sand accretion → threatened insular character.
Dam on Couesnon releases controlled pulses flushing sediments seaward, slowing marsh encroachment.

Component	Ecological Role	Cultural Note
Halophyte plants (samphire)	Brine filtration, niche for invertebrates	Foraged seasoning & local cuisine
Grazing sheep	Vegetation maintenance, nutrient cycling	PDO lamb famed for saline herb diet
Mudflat invertebrates	Food web base (worms, crustaceans)	Supports migratory birds

Always use certified guide: quicksand pockets & tidal channels shift.
Leave no trace: avoid trampling sensitive plant patches; follow existing footprints when instructed.

Challenge	Impact	Response
Climate change sea-level variance	Alters tidal window precision	Continuous hydro-monitoring
Visitor foot erosion near dunes	Vegetation loss	Boardwalk routing & signage
Plastic micro-debris	Invertebrate ingestion	Shoreline cleanup initiatives

For “mirror” shot: incoming mid-tide on calm day, low wind (<10 km/h) for reflective wet sand.
Use telephoto to compress island & marsh sheep for pastoral narrative.

Respecting tidal cadence and marsh fragility elevates your experience from spectacle consumption to ecological stewardship.