Preserving large trees as runoff interceptors is an integral part of low impact development as well as incorporating trees and vegetation in filtration beds, rain gardens, and bioretention systems. These systems are extremely beneficial and provide essential functions of the natural landscape: infiltration, evaporation, transpiration, interception, and shading.
Depending on the type of tree or vegetation retained on-site or planted within the facility there is a different type of load released throughout the year….organic matter. Organic matter for a green field is extremely beneficial as the load can easily be assimilated, allows for decomposition, and provides essential nutrients for soil and nourishment for future vegetation. Organic matter for a stormwater facility can be beneficial, but also can increase excessive nutrient loads that cannot be assimilated, block inlets, blind surface beds, alter flow paths, and change percolation rates through the soil.