West Lake

 artificial lake, boating

Until the 1880s this was a cienega, a natural swamp land.
It was dredged out to become a public park, complete with boathouse.
This new recreational reservoir was named West Lake because, at that time, it lay just within the western boundry (now known as Hoover Street) of the City of Los Angeles.
By the 1890s the Westlake Park area was among the most fashionable neighborhoods in Los Angeles, and Victorian mansions were being built on Parkview Street.
In 1934 a causeway was built across the middle of West Lake, for the westward extension of Wilshire Boulevard. This left the southern part the lake about half the original size. (The much smaller part north of Wilshire eventually became little more than a stagnant pond, and in the 1980s it was filled in.)
Technically speaking, this body of water is still West Lake, but it has become better know as the MacArthur Park Lake.