 Naples Creek rises in the foothills of the Santa Cruz Mountains at an approximate headwaters elevation of over 400 feet and runs southwest through agricultural land and urban developed areas in the lower reach to the Pacific Ocean.Regionally, both the surface water and the groundwater flow with the slope of the terrain, that is, from the northeast to the southwest.Groundwater in the lower reach has been found at 20 to 80 feet below the surface in unconsolidated Quaternary marine terrace deposits and in unconsolidated Quaternary alluvium.