Gravity is the power source in Holt’s bucolic plumbing system, with water from an elevated reservoir flowing down through the structure of pipes into a pre-existing ditch. Dating back to the 18th century, this ditch is dubbed a “ha-ha” by Irish hunters because of the surprise they experienced when encountering it. Gravity is the power source in Holt’s bucolic plumbing system, with water from an elevated reservoir flowing down through the structure of pipes into a pre-existing ditch. Dating back to the 18th century, this ditch is dubbed a “ha-ha” by Irish hunters because of the surprise they experienced when encountering it.























