Update state Dender after 1939, Oudegem, Denderbelle

Add old Dender stretch Denderbelle

Fix location of oude Dender based on current day imagery

Update state Dender until now, Gijzegem and Mespelare

Update state Dender until 1969, Gijzegem and Mespelare

Update state Dender until 1938, Gijzegem and Mespelare

Update state Dender until 1904, Gijzegem and Mespelare

Update end year of small old Dender piece to before the big bridge was constructed.

Update state Dender until 1873, Gijzegem and Mespelare

Update introduction date Dender boat turning point, Hofstade

Update state Dender after 1873, Hofstade

Update state Dender until 1873, Hofstade

Fix Dender state Aalst 1873 - 1904

Fix inconsistency

Update state dender from 1969

Fix end year water element

Correct street introduction date

Update Dender river state in Aalst before 1939

Update Dender river state in Aalst before 1904

Update Dender river state in Aalst before 1865