《汉书·志·地理志上》
俞元县，池水在南面，桥水发源地，向东到毋单县流入温水，行程一千九百里。
俞元，池在南，桥水所出，东至毋单入温，行千九百里。
Yuan County has a pond in the south and a bridge in the water source. It flows east to Wushanduan County and enters Wen Shui, covering a distance of 1,900 miles.