hi,

diploma passed candidates are eligible to apply for btech or b.e course throgh lateral entry admission test by clearing lateral entry exam on direct second year of btech course. So you are eligible to do btech after completing your diploma. I have mentioned some institute name which provides btech in water resources engineering,

Jawaharlal Nehru Technological University

anna university

ignou

Hindustan Institute of Technology and Science

Sam Higginbottom Institute of Agriculture, Technology and Sciences (SHIATS)

there is no age bar to admission in ignou, you need to submit the application with all your documents , admission is done on 2 times a year, january and july session.