Vegetative maintenance on tax ditches is performed to allow access to channels for the removal of accumulated sediments, commonly referred to as "dip outs." Dipping out a channel is done using a hydraulic excavator that removes approximately one to two feet of material from the channel bottom. This allows the channel to remain fully functional and provide the level of drainage intended by its original design. Dip outs generally occur once every 15 to 20 years.
Vegetative maintenance traditionally involves the use of rotary mowing machines to control trees and large shrubs. Failure to perform this maintenance will result in the growth of large trees and prohibit access to the channel for dip-out purposes. Unfortunately, mowing machines are not selective and cut all vegetation including shrubs and grasses that provide desirable food and habitat for wildlife. Recent attempts have focused on the development of viable alternative methods for controlling vegetation. One successful method is the “weed wiper bar." This machine applies herbicides to woody vegetation by using a wiping bar that does not harm more desirable species.
An experimental maintenance practice to promote increased wildlife habitat involves the establishment of tree clusters along the edge of the ditch. This practice yields numerous environmental benefits as it increases tree canopy, reduces forest fragmentation, provides shade thereby lowering water temperature, and increases the dissolved oxygen in the water.