This beach is shallow, so even kids can swim safely here.
I don't want to become a person with shallow thoughts.
Whenever I get drunk, I only get light sleep and wake up early in the morning.
This is a single kanji with an い on the end, meaning you know it's probably an adjective. What's the adjective form of shallow? It's shallow.
The reading is the one you learned with the kanji, making this あさい