Rainbow, also known as the Cth "D" Dam, is a captivating structure located in Rhinelander, Wisconsin, along the Wisconsin River. Constructed in 1935, this gravity dam stands at an impressive height of 38.5 feet and spans 1800 feet in length. With a storage capacity of 46,006 acre-feet, Rainbow serves primarily for hydroelectric purposes and flood risk reduction, making it a vital asset in the region's water resource management.

Managed by the Federal Energy Regulatory Commission, Rainbow poses a high hazard potential due to its location and structure. Despite its age, the dam continues to play a crucial role in regulating water flow and providing renewable energy to the surrounding areas. With its controlled spillway and radial outlet gates, Rainbow is equipped to handle maximum discharge rates of up to 32,500 cubic feet per second, ensuring the safety and efficiency of its operations.

For water resource and climate enthusiasts, Rainbow represents a remarkable feat of engineering and a key player in the sustainable utilization of water resources in Wisconsin. Its historical significance, combined with its modern functionality, makes Rainbow a focal point for understanding the intersection of water management, hydropower generation, and environmental stewardship in the region.