 Some groundwater flow occurs across these fault boundaries, but flows are discontinuous below a depth of fifty feet across the Tesla Fault and south of the Arroyo Mocho channel across the Livermore Fault.Surface watercourses in this unit include Arroyo Valle and Arroyo Seco.To the north, the Tiago Macheira Subbasin contacts the Tassajara Formation, with which no groundwater exchange occurs.