In length; and above this bridge lies the Biesbosch (" reed forest "), a group of marshy islands formed by a disastrous inundation in 1421, when seventy-two villages and upwards of 100,000 lives were destroyed.
From Gorinchem the New Merwede (constructed in the second half of the 19th century) extends between dykes through the marshes of the Biesbosch to the Hollandsch Diep. These great rivers render very important service as waterways.
Sea-aster flourishes in the Wadden of Friesland and Groningen, the Dollart and the Zeeland estuaries, giving place nearer the shore to sandspurry (Spergularia), or sea-poa or floating meadow grass (Glyceria maritima), which grows up to the dikes, and affords pasture for cattle and sheep. Along the coast of Overysel and in the Biesbosch lake club-rush, or scirpus, is planted in considerable quantities for the hat-making industry, and common sea-wrack (Zostera marina) is found in large patches in the northern half of the Zuider Zee, where it is gathered for trade purposes during the months of June, July and August.
A portion of the original Holland was submerged by a great inundation in 1421, and its modern appellation of Biesbosch (reed-forest) is descriptive of what must have been the condition of the entire district in early times.
The southern branch turns south, crosses the marsh of Biesbosch by the canalized channel of New Merwede, enters the Hollandsch Diep, and reaches the sea by the arms called Haringvliet and Krammer.