Reed Canarygrass is known to take over entire fields and choke out creeks and ditches. It can increase flooding and strand juvenile salmon. While it can look similar to other grasses, look for 3-6 ft tall plants with papery ligules where leaves split off (see image below). 

Once the ID is confirmed, removal using a shovel is your best bet. Make sure to dig up as much of the dense roots as possible! 

(Image credit: Noxious Weed Control Board)