Update state of moats round Dendermonde before 1830.

state of moats round Dendermonde, 1815/1830 - 1873

Update state of moats round Dendermonde, 1987 - now

Update state of moats round Dendermonde, 1969 - 1987

Update state of moats round Dendermonde, 1904 - 1947

Add moat round Dendermonde, state 1873 - 1938

Update Dender river flow, Aalst to Schelde before 1939

Update Dender river flow, Aalst to Schelde, 1939 - 1964

Fix missing Dender river section, Aalst, 1964-1969

Fix Dender river flow, Aalst to Schelde, 1964 to now

Update state Dender before 1873, Dendermonde

Update state Dender after 1873, Dendermonde

Update state Dender after 1904, Dendermonde

Update state Schelde before 1978, Dendermonde

Update state Dender after 1987, Dendermonde

Fix end date should be start date

Update state Dender after 2012, Dendermonde

Update state Dender after 2015, Dendermonde

Fix start year of Lock near Denderbelle

Update state Dender 1771-1840, Oudegem and Denderbelle