Looks cool! Here's my suggestion (for 3.5).

Healing Oasis
A remote oasis in a vast and deadly desert. Palm trees and small shrubs encircle a pool of cool, clear water.

Knowledge (geography, local, or nature). The oasis and its healing powers have been used for the benefit of desert traders, raiders, and tribes alike for centuries.

(DC 10) The pool's waters are drinkable, and the various fruits (figs etc) provided by the surrounding flora are safe to eat.

(DC 20) Resting at the oasis allows a creature to heal even from wounds inflicted by life-draining undead.

(DC 25) It is said that the oasis will one day restore a creature to life, albeit at great cost.

None. Even simple animals have learned to benefit from the oasis.

Simply harvest and eat some of the plants, sleep in the oasis, or place a corpse in the pool.

The plants produce up to 2d4 berries, herbs, or fruits per day, and the pool's waters can heal up to 8 creatures per day. These powers function indefinitely (but see Destruction, below).

The harvested plants acts as goodberries (lasting 9 days before spoiling).

Resting at the oasis for at least 8 hours allows a character to heal as though they had received a full day of long-term care (regaining 4 hit points per level and healing 4 points of ability damage to each ability score). Ability drain may be healed as though it were ability damage for this purpose.

If a corpse is placed in the pool, it is revived as if by raise dead.

Moderate conjuration (healing)

Using the raise dead power causes all the plants to wither and dries up the pool, permanently destroying the oasis.

7,250 gp.