Rainbow Lake is , with a maximum depth of and an average depth of . It is a part of the Walnut Creek drainage, which fills three lakes in the area, including Woodland Park Lake (owned by the Town of Pinetop-Lakeside), Rainbow Lake, and the privately owned Lake of the Woods. Rainbow Lake is mostly surrounded by homes, including the private HOA Shores at Rainbow Lake on the southeast side. It is a prominent recreational feature of the Pinetop-Lakeside area, known for its fishing, boating, and wildlife habitats. Currently, Arizona Game and Fish stocks the lake with catchable-sized
rainbow trout in the spring and early summer. Naturally propagating warm water species include
largemouth bass,
channel catfish,
black bullhead,
bluegill and
green sunfish. The lake also contains illegally introduced
northern pike. Because it is shallow and weedy, Rainbow Lake is subject to significant water quality problems. In past years, Rainbow Lake has also had a significant problem with invasive aquatic weeds, particularly the
Eurasian watermilfoil,
Myriophyllum spicatum. Efforts by the local volunteer group
Show Low Creek Watershed Enhancement Partnership (SLCWEP), in conjunction with the Little Colorado River Plateau Resource Conservation and Development Area, Inc., resulted in a systemic
herbicide treatment of the lake in the summer and fall of 2011. The results were not as good as hoped, with the equally problematic
coontail weed rapidly replacing the watermilfoil in the lake. Long-term efforts by the Rainbow Lake Coalition (a subcommittee of the SLCWEP) are now focused on the introduction of sterile white Amur
carp, which have been proven to control excessive growth of watermilfoil for up to 10 years. Arizona Game and Fish requires mediation to ensure that the carp, a non-native fish, are prevented from escaping Rainbow Lake and potentially invading other water bodies. The Rainbow Lake Coalition is now working to design and construct a fish barrier on Walnut Creek below Lake of the Woods, which has used the carp for weed control for many years. ==Fish species==