Sequim (pronounced "skwim") is a city in Washington State with a population of just under seven thousands residents. After European settlement began in the 1850s, the area adjacent to the Dungeness River proved to be fertile farmland, but the vast prairie surrounding it – known as "the desert" – lay barren. A massive effort to build irrigation canals commenced in the 1890s, with an annual Irrigation Festival held every May since 1895. It holds the record for the longest continuously-running festival in Washington State, and in 2016 offered a pictorial postmark for the festival's 121st year.
For this cover, I masked the outline of Washington State against a photograph from Sequim with a migratory heron, enjoying the wetlands, in the lower-right. In the background is a faded picture of the nearby New Dungeness Lighthouse, a functioning navigation aid on the Strait of Juan de Fuca. I used stamps commemorating Washington's Semicentennial and Centennial of statehood (Scott #858 and #2404, respectively), and a single of the Soil and Water Conservation issue of 1984 (Scott #2074) and sent for the postmark by mail.
More on Sequim: https://en.wikipedia.org/wiki/Sequim,_Washington
Irrigation Festival official homepage: http://www.irrigationfestival.com/
Sequim Irrigation Festival Facebook page: https://www.facebook.com/SequimIrrigationFestival/
You can order the postmark for yourself through June 6th: http://collectpostmarks.com/postmarks/121st-irrigation-festival-station-sequim-wa-2016-05-07/