BEND — The Sunriver Nature Center & Observatory continues to welcome more visitors than its facilities can reasonably handle.

About 50,000 people visit the center each year, which is well above the 10,000 visitors the center was designed to handle when it was built in 1984.

To address the growth, the nature center and observatory launched a $5 million fundraising campaign last year to build major expansions on the center’s 8-acre campus, which features pine trees, wetlands, meadow habitats and an observatory. Nearby Lake Aspen is home to the center’s beloved trumpeter swan population.

Marvin Henberg, volunteer and chair of the fundraising campaign, said the expansion is badly needed.

“We just don’t have the space to do what we need to do,” he said.

So far, about $1.7 million has been raised. And about $1.5 million of it has been raised from the individual private donations.

The community support gives the campaign credibility with organizations that may be interested in making large donations, Henberg said.

“You get more credibility with foundations and corporations if you can show a big support from private individuals,” Henberg said.

The nature center plans to update its facilities in two stages. The first stage focuses on expanding its Oregon Observatory to double its capacity and build an 1,800-square-foot pavilion on the back of Lake Aspen.

Both projects are expected to be complete by the end of 2020.

The pavilion will provide an outdoor learning space to better serve the nearly 5,000 students that visit for camps and programs each year. Today, all the students have to share one classroom inside the nature center.

“Having the additional classroom out on Lake Aspen will allow us to run all-day camps and programs,” said Abby Rowland, director of philanthropy at the nature center.

The observatory draws up to 400 visitors on busy nights, which often means people have to wait to use telescopes and do not get as much one-on-one time with the observatory astronomers.

Doubling the capacity of the observatory will give visitors more opportunities to use the NASA-affiliated facility.

“To have the space to provide that type of science education is pretty incredible,” Rowland said.

The second stage of the expansion plan is a longer term project the nature center hopes to complete by June 2021: a 7,700-square-foot Discovery Center that will include a planetarium theater with a full projection system and seating for up to 94 visitors.

The Discovery Center and planetarium theater is expected to cost more than $3 million to complete.

Part of the fundraising campaign is offering naming opportunities for the new features. For example, a person or company can have their name on the Discovery Center for a $2 million donation. A name in the Discovery Center foyer is going for $150,000.

The initial fundraising support and interest from the community has shown the nature center that Sunriver is ready for larger facilities, Henberg said.

Sunriver has experienced a rise in visitor growth in recent years, which has led to building the Village at Sunriver and the Sunriver Homeowners Aquatic & Recreation Center.

“We feel like it’s time for the nature center to catch up,” Henberg said.