large, south-flowing tributary on the right bank; this tributary is now diverted into culverts and called the Arroyo Salada Storm Channel. It is speculated that Sulphur Creek, a tributary of Aliso Creek to the north, originally flowed into this creek, and as a result was a tributary of Salt Creek. Flowing through a golf course in a small canyon near the Pacific, several canyons join the Salt Creek Canyon on the left bank, then Salt Creek is diverted into a massive concrete culvert that takes it underground through the original course of a canyon that is now filled in. The culvert discharges onto a concrete apron at Salt Creek Beach, where Salt Creek is treated before it enters the sea. Watershed At in size, the watershed of Salt Creek is the smallest major watershed in the county. Shaped roughly like a "Y", the two arms of the mostly residential watershed represent the drainage basins of Salt Creek and its major tributary, the Arroyo Salada Storm Channel. Bounded almost entirely by the San Joaquin Hills, the watershed consists of a hilly region east of the Aliso Creek watershed, south of the Sulphur Creek drainage basin, and west of the valley of San Juan Creek and Trabuco Creek. The easternmost part of the watershed lies within San Juan Capistrano, and the southernmost part between Dana Point and Laguna Beach. Two-thirds of the watershed lies within the city of Laguna Niguel. If not for the uplift of the San Joaquin Hills approximately 1.2 million years ago, the Salt Creek watershed may have a different geography altogether. The unnamed tributary that now is diverted into the Arroyo Salada Storm Channel was once part of the course of Sulphur Creek, a tributary of Aliso Creek to the north. The historic creek had a length of around , far longer than the present-day mainstem of Salt Creek. At that time, the Sulphur Creek-Arroyo Salada combination would have represented the mainstem of the Salt Creek watershed, draining southward towards the Pacific, and would have added over to the Salt Creek watershed. A low saddle now divides the two drainage basins. Effects of Channelization Due to channelization during urban development, the source of Salt Creek, which was a small marshy wetland but has been replaced by a community pool, is no longer where it was before the area was developed in the 1990s. At that point, The flow