The Effects of Trees on Stormwater Runoff
This report summarizes the results of a literature review done for Seattle Public Utilities in 2008 of research conducted to quantify the effect of trees on stormwater runoff.
Trees affect stormwater runoff through three primary processes: interception, transpiration, and infiltration. Interception is the collection of precipitation on the structure of the tree and the subsequent evaporation of moisture, which would otherwise become runoff. Transpiration is the transfer of water from the soil through the tree and its eventual release in a gaseous form through microscopic pores in the leaves and stems. Infiltration is the movement of surface water through the soil. Tree roots, combined with organic material that typically builds on the soil at the base of trees, promote the infiltration of runoff through shallow subsurface zones, helping to reduce both the rate and volume of stormwater runoff.
This literature review provides a representation of the range of research conducted and the common conclusions of the various studies. [From introduction]
Northeast, Pacific Northwest
Stormwater Management, xGI