Dartford Fresh Marshes is a relatively small (28 ha) relict area of coastal grazing marsh that forms a southern extremity to a larger 195 ha area of Thamesside marshland called Dartford Marshes. Both grazing marshes are bounded to the west by the tidal River Darent, but are physically separated from each other by the A206 (University Way) which was constructed around ten years ago.
Dartford Fresh Marsh is a floodplain grazing marsh. Floodplain grazing marshes are periodically inundated pasture or meadow with ditches, which maintain the water levels, and contain standing brackish or fresh water. Most are grazed, and some are cut for hay or silage. They contain seasonal or permanent water filled hollows or ponds and emergent swamp communities but not extensive areas of tall fen. They often occur as part of a wider wetland matrix which includes open water, reedbed, and occasionally wet woodland.
Grazing marsh is important for waders and wintering wildfowl, in some cases supporting such large populations that they are internationally important. Grazing marsh may contain both species poor improved grassland and floristically rich semi-improved grassland, depending on how the land is managed. The ditches support a diverse and interesting mixture of invertebrates including many nationally scarce and threatened species.