how do you calculate the depth?

QUESTION:

A water trough has a uniform cross section in the shape of half an ellipse. The width of the trough is 80 cm and the areas of its cross section is 1890cm².

1) The trough is 300cm long. Calculate the number of litres of water the trough will hold when it is full.

2) Calculate the depth of the trough. Give your answer to the nearest centimetre.

Please help