Some of the big national retail chains are opening “super stores” in Iowa. ISU economist Ken Stone says the “big box” stores are adding services and products to offer one-stop shopping.Those superstores include Target and Wal-Mart, which add restaurants and grocery departments to extra-large retail stores. But they don’t add on to the old store when they grow, they abandon it and build a new one.He says it’d be hard to expand an 8-thousand-square foot Hy-Vee to a 20-thousand-foot store. One old Hy-Vee in Ames was made into another business. But Stone says the “big box” store buildings often have few useful purposes once the retailer moves out. He says there’s not much use for a 90-thousand-square-foot building in a small town, and Wal-Mart has hundreds standing empty around the country. Stone adds there have been a few efforts to use the “big box” store buildings for other things like movie theatres or antique malls, and one is in use in Oskaloosa. Other attempts to start up super-discount outlets failed, and were closed. Stone says some of the “big box” store buildings just have to be torn down because once abandoned, they have no use. With the chain that owns Albertson’s foodstores and Osco drugstores closing many outlets around the nation, there’s still no word on whether Iowa towns will find some of their retail stores standing empty.