8 kilometers. Woniu Lake, also known as fengyangshan Reservoir, is named after a hill in the lake that looks like a lying cow. Official website shows that the highway around the lake of fengyangshan Reservoir is 8 kilometers long. Zhu Lin, secretary of Fengyang County Party Committee, accompanied by the heads of Water Affairs Bureau, Ecological Environment Branch, Capital Planning Bureau and Yin Jian Town, went to fengyangshan Reservoir to investigate the river length system and sewage treatment.