sentences:  The creek flows through residential Rancho Mission Viejo, crosses under Interstate 5, and enters a concrete flood control channel, turning south and receiving El Horno Creek on the right.It receives its largest tributary, Arroyo Trabuco, from the right, then flows south toward the Pacific Ocean.The creek forms a fresh water lagoon at the northern end of Doheny State Beach, which overflows into Capistrano Bay during periods of high flow.