 The town began to develop after the completion of the Okanogan Irrigation Project , which was designed to facilitate farming . At this time , many farmers came to Omak looking for homes . Fruits including apples , berries , peaches , plums and watermelons were cultivated after 1910 . Omak served as a census @-@ designated place ( CDP ) in 1910 , and incorporated as a city on February 11 , 1911 . Omak and Okanogan have shared a rivalry in high school sports . During the Great Depression of 1933 , several residents of Omak were forced to work in nearby communities . As a result , the United States Bureau of Reclamation promoted work which was available as part of an improvement project at Grand Coulee Dam in nearby Coulee Dam , which employed approximately 5 @,@ 000 people between 1933 and 1951 when the megaproject ended . By 1950 , the city was home to various buildings and structures including the St. Mary Mission church , which satisfied residential needs . 
