REMEDIAL ACTION WORK PLAN OPERABLE UNIT 2, LANDFILL ...

I Additional Information — Preservationof ExistingVegetation
The bst way to preventexcessiveerosion is to not disturb the land. On a construction site, where extensive land
d~turbance is n~esw.ry, a reasonable BMP would ~ to not disturb land in sensitive areas of the site which need not h
rdtered for the project to be viable (e.g., natural wahwcourses, steep S1OPS),and to design tbe site to incorporate particularly
unique or desirable existing vegetation into the site landscaping plan. Clearly marking and leaving a buffer area
around these unique areas will lmth help to preseme these areas as well as take advantage of naturat erosion prevention
and sediment trapping in nanmlly vegetated areas.
Existing vegetation to be prestmed on the site must b protected from mechanical and other injury while the land is
being develop.d. The purpo~ of protecd.rtgexisting vegetation is to insure the sumival of desirable vegetation for
shade, tiutifiation, and erosion protection. Mature vegetation has extensive rmt systems that help LOhold soil in
place, thus reducing erosion. Also, vegetation helps to keep soil from drying rapidly and becoming susceptible to
erosion. To effectively save existing vegetation, no disturbances of any kind should k allowed within a deftned am
around the vegetation. For tr=s, no construction ac~viw shwld ~ur wi~in he df’iPlime of tie tree.
The following criteria may lx used for decidhg which vegetation will remain on the site:
● Aesthetic va.lucs Consideration should k given to fotiage, flowering habits, bark and crown characteristics (for
trees).
● Freedom horn disease and rot.
● Life span of ties: Shon-lived trees need not lx presemed.
● Environmental values: Hablu sueening; and buffers.
● Suddenex~ure: Save vegetation which grows in duect sunlight and is able to withstand radiated heat from
pro~sed buildings and pavemetm
● Space needed Sufficient space must h! provided lxtween the vegetation and any structures, elmttic and telephone
lines, water and sewer lines, driveways and streets. Mark tr~s and shrubs with bright paint or ribbon so there is no
doubt as to which trees and shrubs are to k left and protected from dsmage during construction.
Saving existing vegetation and mature tr=s on-site, beauti.fks the area and may save money by reducing new landscaping
requirements. Mature trees also increase property values and satisfy consumer aesthetic needs.
preserving and protecting existing vegetation w often result in more stable soil conditions during construction. Careful
site planning and identification of plantings to prewne cart provide erosion and sednentation controls during construction,
and contribute to the aesthetics of the &velopmen~ For example, in Sacramento County a tree ordinance has been
adopttxl that protects the native California Oak tree. Provisions to protect the tm and its rwt system during construction
must k s~citied in the project plans, and an ma must lx provided where the soil stability may not be dkturhed. No
grading or construction storage within the tree dripline is allowed.
Building sites may lMplanned to integrate existing vegetation and wets. Construction impacts must& considered.
Trench width for pip ccmstruction projects and the lom.ion of pmanent structures, such as buildings, needs to lx
considered when preseming existing vegetation, including mature trees and their mt system. Native vegetation should
b preserved since it is able to adapt to the climate. The USDA Soil Consemation Semite should lx contacted about
existing vegetation for sites throughout Cahfmniz Mature trees are generally prefemble to newly planted trees kause
of the greater soil stalil.izadon provided by the extensive at system of a mature uee.
I ESC2
Construction Handbook 5-8 March, 1993