Haohe River, known as the emerald necklace of Nantong, surrounds the old city with a total length of 15km, covering an area of 80 hectares. Used to be a city moat, Haohe River is the only ancient moat in China which remains intact and lies in the center of the city. With a sound, beautiful, comfortable, and harmonious ecologic environment, Haohe River scenic spot was awarded the prize of the Best Living Environment in Jiangsu.
Cities 
I think this is the city of Nantong:
A map: http://www.cityofnanaimo.com/asia/China/ShanghaiRegion.pdf
And a description from http://www.tex-nt.com/charm/charm04.asp:
Haohe River, known as the emerald necklace of Nantong, surrounds the old city with a total length of 15km, covering an area of 80 hectares. Used to be a city moat, Haohe River is the only ancient moat in China which remains intact and lies in the center of the city. With a sound, beautiful, comfortable, and harmonious ecologic environment, Haohe River scenic spot was awarded the prize of the Best Living Environment in Jiangsu.