What is the legal definition of a "small well" (al-Bī'r al-Saghīrah) in Hanafi Fiqh?

Well Purification: Animal Falls and Complete Drainage Rules

• A well containing less than 100 buckets.
• A stagnant body of water whose surface area is less than ten cubits by ten cubits.
• A well deeper than 10 meters.
• A well connected directly to the Nile river.