Listed as a historical engineering site in the state of Missouri, Tunnel Dam is a seventy year old works of wonder.
Completed in late 1930 and in operation by November of that year, it is still providing electricity to the area during peak power usage. Depending on usable
water flow, peak compacity of the dam is 2400 kW with anual production of 7500000 kWh to over 120000000 kWh. The gravity type dam, designed to provide a forty
foot head, includes a rock anchored concrete spillway section twenty four feet in height and three hundred feet in lengh as well as a rock and dirt filled embankment
with a steel sheet pile supported concrete core wall extending five hundred feet to the west bank.
Driving on the top of a ridge on the road most known by locals as "The Narrows", you can see lake Niangua, Tunnel Dam, and the
river valley below.
Lake Niangua extends two and a quarter miles upstream and approximently one quarter of a mile wide and varies in depth throughout the year.