Orman Dam still providing farmers with water after 100 years

RAPID CITY, S.D. (KOTA TV) - When Orman Dam was built, it wasn't expected to last long. Some people say it was rumored to last only 50 years, but the dam has doubled it’s expectancy.

Orman Dam and the Belle Fourche Reservoir have been providing farmers in the Northern Hills with irrigation capabilities since 1912, and today serves at maximum capacity.

“We have 57,143 acres I believe,” said Bill Anderson, Project Manager of the Belle Fourche Reservoir, “That is the state limitation, we cannot exceed that.”

When construction started on Orman Dam in 1906, engineers didn't use modern construction practices. It's made mostly of native clay soils, but Anderson has a theory as to why it works so well.

"I think it got good compactions because of the mules and horses,” said Anderson, “Those hooves have good compaction."

The original idea was to use using gravity to push water to farmers in the area, but now different practices are used. Anderson says nearly 20 percent of the acres in the project are using pivot irrigation systems.

Some parts of the project have been updated from the original clay pipes and open canals. Nearly 41 miles of pipe have been laid underground, but other areas are still functioning as they did 100 years ago.

“We still have 400-some miles of dirt ditches which are not terribly efficient,” said Anderson, “There is a lot of losses on those dirt ditches.”

Anderson says the tow drain on Orman Dam runs 8-10 gallons year round, while the neighboring Angastora Reservoir runs nearly 200 gallons.

Although the dam is directly impacting farmers in the project, the wealth does not stop there.

"It’s not just the immediate farmers, it is the entire tri-state area,” said Anderson “There is a lot of economy that depends on this project."