REV3 APPROVED-STREET TREES-DUCT BANK-TRA MEMOI. A N I) M C A E` r A K A §I I I F C I li R i I I I EI' I. A ^J N J N 6 i1 I, B A N :7 E S I k; N
22 October 2020
Mr. Lucas Branham
Studio Meng Strazzara
2001 Western Avenue
Suite 200
Seattle, WA 98121-2114
Lucas,
Thomas Rengstorf and Associates (TR&A) have reviewed the Dry Utilities Plans with a revision date 10.21.20
from Navix Civil Engineers. We have determined that the minimum four (4) foot burial depth of the telecom duct
banks indicated in the above referenced plans and section should not impact the installation of the proposed
street trees indicated on the Planting Plans and associated details. The planting documents illustrate the depth
of the tree planting pit shall be 24-inches in depth to accommodate the rootball from the nursery. Additionally,
studies indicate that most trees develop shallow spreading root systems with the majority of the roots found
within two (2) feet of the surface. Roots occur where favorable conditions exist (loose soil, water, oxygen and
nutrients) and these conditions are found near the soil surface. TR&A does not anticipate that the tree root
system will have any detrimental impacts on the duct banks indicated on the Dry Utility Plans.
Scott Evans
042000M
Thomas Rengstorf & Associates