On March 7, 2012, Washington Governor Christine Gregoire signed Engrossed Second Substitute Senate Bill 5292, which expressly excludes irrigation and drainage ditches “that lie within the boundaries of and are maintained by a port district or an irrigation district or company” from the definition of fish and wildlife habitat conservation areas under the Growth Management Act’s critical areas regulations. Interestingly, when this bill was first introduced in the Washington Legislature in 2011, it was much broader; the exclusion was not limited to drainage ditches within the boundaries of port and drainage districts. In fact, the original bill stated “Critical areas do not include irrigation and drainage ditches, grass-lined swales, canals, detention facilities, wastewater treatment facilities, or farm ponds.”

During the 2011 legislative session, the original bill was revised to limit the exemption to drainage or irrigation ditches constructed by or within the boundaries of an irrigation district. In 2012, the legislature reexamined this bill and further amended it to expressly exclude “artificial drainage ditches” that lie within the boundaries of and are maintained by a port district. While slightly broader than the revised bill from 2011, the 2012 bill that ultimately passed does not exclude all man-made ditches from critical area regulations. Such ditches that lie outside port and irrigation district boundaries and are not maintained by these quasi-governmental agencies still remain subject to regulation as fish and wildlife habitat conservation areas.

The critical area regulations had previously excluded artificial drainage and irrigation ditches from the definition of wetlands, if those ditches were “intentionally created from non-wetland sites.” When analyzed closely, this exclusion does not apply to all drainage ditches. In addition, federal and state wetland statutes and regulations do not have the same exclusion, and often roadside or agricultural drainage ditches effectively meet wetland delineation criteria and therefore are subject to federal and state wetland permitting requirements. Accordingly, if your project could potentially impact a drainage ditch, carefully review these exclusions to determine which regulations do and do not apply to your project.