Spring fed so it wont be stagnant and have the issues associated with that. It stays crystal clear, only muddy in the pic because I was just digging around in it. Its about 1 foot or so deep best I remember and 4-5 feet across. It was filling up while I took the pic. My plan is to take a mini excavator in this Winter and really give it some size. I think it was between 16-17 gallons per hour output that I calculated it at.