I would still use the natural area. But, guide the water toward it by excavating a more subtle grade toward the natural area. Disturb the least amount of soil as possible. If this idea doesn't intrigue you, shoot the elevations and see where it makes the most sense to re-direct water. The answer may be obvious. Gentle slopes minimize erosion, but be sure to vegetate the slope, or use something such as riprap to slow water flow as it makes its exodus.

Teach a man to grow fish...
He can teach to catch fish...