The pilot elected to land on the 2,100-foot long grass runway with a tailwind of about 10 knots. After the aircraft passed the middle of the runway, the pilot realized that the aircraft would not stop in the remaining distance. Knowing that there was a downhill overrun that ended in the water, as the aircraft neared the end of the runway, the pilot elected to turn off the runway onto up-sloping terrain covered by tall grass. While rolling through the tall grass, the aircraft encountered a drainage ditch, resulting in the collapse of the nose gear and one main gear.