'Lower' in the Bible

And ye saw the breaches of the city of David, that they were many; and ye gathered together the waters of the lower pool;

Sing, O ye heavens, for Jehovah hath done it; shout, ye lower parts of the earth; break forth into singing, ye mountains, O forest, and every tree therein: for Jehovah hath redeemed Jacob, and will glorify himself in Israel.