Northern Subbasin Overview
The Northern Subbasin includes the watershed area immediately north of the SLR River from Rice Canyon, approximately one mile east of Interstate 15 (RM 20), to just upstream of the Escondido Canal Diversion (RM 40) (Figure 2). This subbasin does not include the SLR River, rather all the tributaries north of the river within this geographical area. Differing from the lower elevations and alluvial streams in the Southern Subbasin, most of the Northern Subbasin tributaries flow out of the steeper, higher Agua Tibia Range and Palomar Mountain as a part of the southern Peninsular Ranges of southern California. These mountain ranges, particularly the area around Mount Palomar, typically receive over 30 inches of annual precipitation, considerably more moisture than the rest of the basin. Stream elevations range from 300 feet in the southwestern portion of the subbasin to approximately 5,200 feet in the headwaters of Doane and French creeks, near Palomar Mountain State Park. The Northern Subbasin occupies less than one fifth of the total basin at 92 square miles and is the second smallest subbasin behind the Middle Subbasin.
This assessment area is predominantly rural, containing only portions of the small communities of Pala and Pauma Valley. Almost a third of the basin is held in Indian tribal lands, primarily between the three tribes: Pala Band of Luiseño Indians, La Jolla Band of Luiseño Indians, and the Pauma Band of Mission Indians. A portion of the Rincon Band of Mission Indians Reservation is also located within the Northern Subbasin. The remaining land area is held in larger private parcels managed for agricultural crop production and federal and state lands. The Northern Subbasin provides suitable habitat for steelhead trout in several tributaries to the SLR River, but most of these streams have fish passage barriers, hindering steelhead’s access to potential spawning and rearing habitat. Historical evidence documents steelhead in Gomez Creek, Pala Creek, Agua Tibia Creek, Frey Creek, and Pauma Creek. Pauma Creek and a few of its tributaries currently support a healthy population of native, self-reproducing rainbow trout. Genetic sampling performed on these fish concluded that “it seems more than likely that these fish are part of a native coastal O. mykiss lineage” (NOAA 1999). This report went on to state, “these populations may be reasonable choices to consider in efforts to re-establish anadromous runs in their respective streams.” Pauma Creek’s resident trout population is currently blocked from accessing the SLR River due to the impassible culvert that runs below Highway 76. This culvert also prevents passage upstream into the Pauma Creek watershed. Prior to the 2007/2008 CDFG stream surveys, very few surveys have been conducted in any of the tributaries in the Northern Subbasin.
View of Pauma Valley and Pala. Photo taken in 2007.