I want to project for river change detection so may I know from where can I get these temporal data daily and weekly from the past 30 years and which data will be best suited.
If you need channel planform location I think you can use one dataset of each year as rivers do not change there course on a daily basis. The best source is glovis.usgs.gov where you can get satellite data of most areas of the world from 1972 onwards which will cover your 30 years period.
I think the most appropriate sensor for that period is TM in Landsat sateliltes. The resolution (30m) can be not very good but is the best for 30 years ago
Every country have its own river flow monitoring stations physically one the daily basis for every river, i don't now u belong to which nation, if u r from India, contact hydrology dept. of govt. of India.