が豊富だ

is abundant in

→ が
phrase Uncommon #12,081
is abundant in Used after a noun to say that something contains a lot of it or has plenty of it.
JA: この地域は水が豊富だ。
EN: This region is abundant in water.

果物が豊富だ

There is an abundance of fruit.

— コーカサスの虜 (1996)

彼はフランス語の知識が豊富だ。

He has extensive knowledge of French.

アメリカは石油が豊富だ。

The United States is rich in oil.

あの国は石油が豊富だ。

That country is rich in oil.

中国は天然資源が豊富だ。

China is rich in natural resources.