The Tributary Supplementation Program began during the 2015 drought and uses the KRD canal to augment flows to upper Kittitas County tributaries that are intersected by the main and south branch canals. Water conservation is the key component of this program. The ability to supplement flow to thee creeks is dependent upon increasing canal capacity to deliver both the irrigation and tributary water. During the 2018-19 winter season KRD lined 4300' of the south branch canal and 2185' of the north branch resulting in an estimated total savings of 920 acre-feet of conserved water.
Tributaries currently receiving augmented flow include: Tucker, Big, Little, Tillman, Taneum and Manastash creeks. Nelson and Swauk creeks are being evaluated for potential future flow supplementation.