There's a wakeboarding club across the river from Shinsegae... I think

After watching a horde of wakeboarders in the Suyeong river yesterday, my girlfriend and I decided to head over to the little floating shack on the other side of the river to see if it's open to the public. And we think it is. It had a bunch of wakeboards and wetsuits on the wall, lots of people having fun and a big sign that said wake and skii club. 

So I walked over to the information desk and no one was there,  I walked around looking for staff, but you couldn't tell who was what and absolutely everyone was determined to ignore me. After making eye contact with several people( who quickly looked away)  and asking loudly in Korean if there was any information at the information desk, and saying hello to several people, I was no closer to having anyone acknowledge my existence. I can only assume they weren't a fan of my white skin.

Anyways, does anyone know anything about that place? It'd be awesome to go wakeboarding    (haven't done it in years).