Manita is the director of an association dedicated to exploiting the full potential of inland water recreation. The association also lobbies and initiates to better use cultural and natural heritage in relation to the recreation.

She has held several political functions within the municipality of Delft and the province of Zuid-Holland. From 2007 to 2009 she was a regional minister for Zuid-Holland. She has started her career as a teacher.

Since 2010 Manita has been the managing director of Vereniging Regio Water and has guided several projects in the area of Zuid-Holland in the field of waterways and water recreation.

During the INTERREG IVC project European Waterways Forward she was the thematic leader. This project ran till 2012. As the lead partner of the Interreg Europe project SWARE (Sustainable heritage management of waterway regions) she is also responsible for the general knowledge sharing during the project’s lifetime and beyond. This project runs from 1 April 2016 until 30 September 2020.