The Sulphur Creek watershed was once part of the territory of the semi-nomadic Acjachemen Native Americans, who were colonized by the Spanish in the 17th and 18th centuries and called the Juaneño after nearby Mission San Juan Capistrano.

[5] U.S. Geological Survey (USGS) topographic maps show the historic channel of the creek beginning slightly further north, under what is now the SR 73/Greenfield Drive interchange.

[6] The upper section of the creek is a narrow corridor of restored wetland, with the exception of concrete culverts under Moulton Parkway, Nueva Vista Drive and La Paz Road.

[8] The creek makes a sharp turn to the north at Crown Valley Park, where it receives two tributaries from the left, the Niguel Storm Drain[3][9] and a smaller unnamed stream.

[3][10][11] The creek exits the dam via a concrete spillway on the east side and flows through the middle of Laguna Niguel Regional Park.

[19] The San Joaquin Hills around the Sulphur Creek watershed are composed primarily of marine sedimentary rocks dating from the Miocene (23–5 million years ago).

At some point in time, it was captured into the Aliso Creek watershed, creating its sharp northward turn at Crown Valley Park.

[25][26] The Acjachemen were named the Juaneño by Spanish priests in the 18th century, who established a mission at the present-day location of San Juan Capistrano.

[27] In the 1960s, the City of Laguna Niguel bought a large portion of the ranch from the Moulton family; it was later donated to the county for recreational use.

In 1970 the Orange County Flood Control District purchased the dam and reservoir, and the 236-acre (0.96 km2) Laguna Niguel Regional Park was established around it in 1973.

[30] Most of this native habitat was cleared for housing beginning in the 1960s, although a few undeveloped areas remain along hillsides, especially around Laguna Niguel Regional Park.

A number of exotic plant species have been introduced to the Sulphur Creek watershed including Arundo donax (giant reed), castor bean and tobacco tree.

[31] It can grow extremely fast with a high rate of water consumption, and during flood events, arundo segments can be washed downstream, establishing new colonies.

"[34] Increasing concentrations of nutrients from fertilizer and other pollutants in urban runoff have caused algae blooms and eutrophication in the creek above Laguna Niguel Lake.