Rains and storage capacity

Plenty of water in rainy season flows down stream in Yamuna .
Why this water cannot be stored baffles me.
Delhi is water starved city and we depend on generosity of neighboring states.
Expended on storage and water harvesting. Is worth while and as important as common wealth games.
WATER LEVEL is foxing down every year.
Why not to charge our earth in parks and other goby buildings inclu,ding schools and. Colleges.
Kk ghei