General Plan - Moreno Valley

CHAPTER 7 - CONSERVATION7.4 SOILS7.4.1 BackgroundThe United States Soils ConservationService (SCS) mapped soils within WesternRiverside County. A general classificationused in soil mapping is called a soilassociation. An association is a landscapethat has a distinctive pattern of soil types.Identification of soil associations is helpful to1) get a general idea of the soils in an area,2) identify large areas of land suitable for aparticular purpose, and 3) to identify generalareas with potential constraints.Five soil associations are found within theMoreno Valley study area. The Monserate -Arlington - Exeter Association is found onterraces and on old alluvial fans adjacent toand within the eastern half of March AirReserve Base. It consists of well-drainedsoils that developed in alluvium frompredominantly granitic materials. Thisassociation is found on nearly level tomoderately steep slopes from 0 to 25percent with a surface layer of sandy loamand a shallow to deep sandy clay loamhardpan.The Hanford - Tujunga - GreenfieldAssociation occurs on alluvial fans and floodplains. It is common in the central portion ofMoreno Valley, generally extendingnortheast to southeast of March Air ReserveBase. This association consists of welldrainedto somewhat excessively drainedsoils, developed in granitic alluvium. Thesesoils are found on nearly level to moderatelysteep slopes of 5 to 15 percent. They havea good topsoil layer of coarse sandy loamtexture with underlying layers that arecoarse sandy loam and loamy sand.Cieneba - Rock Land - FallbrookAssociation is found on uplands located inthe Box Springs Mountains area, extendingeast to Reche Canyon as well as the MountRussell area. These soils are formed incoarse-grained igneous rock. ThisMORENO VALLEY GENERAL PLANassociation consists of somewhatexcessively drained soils on undulating tosteep slopes ranging from 5 to 50 percent.They generally have a poor topsoil layer ofsandy loam above a layer of gravelly coarsesand and a third layer of weatheredgranodiorite. Rock outcrop areas arepresent along with weathered rock close tothe surface.The San Emigdio - Grangeville - MetzAssociation is found on alluvial fans andfloodplains. The soils along the westernside of Gilman Springs Road comprise thisassociation. These soils are well-drainedand found on nearly level to very steepslopes ranging from 0 to 50 percent. Theyhave good topsoil and an underlying layerconsisting of fine sandy loam.The Badlands - San Timoteo Associationsoils occupy the area along the northernside of Gilman Springs Road into theBadlands region. This association consistsof well-drained soils found on steep to verysteep slopes ranging from 30 to 70 percent.The soils are variable, consisting of softsandstone, siltstone, and beds of gravel.These soils also range in texture from sandyloam to clay loam, having poor topsoilcharacteristics. The very shallow depth tobedrock severely limits the use of septictank sewage disposal systems in this area.Soil stability is considered poor to fair withsignificant potential for erosion.In general, prime agricultural soils are foundon the alluvial deposits of the valley floor,while the soils subject to the greatestlimitations for agriculture and developmentare located in the Box Springs Mountains,Reche Canyon area, the Badlands and theMount Russell area.7.4.2 Issues and OpportunitiesWith exception of the Cieneba - Rock Land -Fallbrook Association and the Badlands -San Timoteo Association, soils within thestudy area present few limitations forPage 7-6 July 11, 2006