The Iowa DNR has announced it’s closing the beach at Backbone State Park in Delaware County because of a high bacteria reading in the water.Monitoring turned up e-coli levels almost seven times higher than EPA recommendations. The DNR’s decided to close the beach at Backbone, suspecting “human sources” may be part of the reason for the high bacteria count. The DNR also says it’s investigating the wastewater treatment plant at Strawberry Point to see if it’s violating its permit by inadequately treating sewage before it dumps it into a stream that flows into the Maquoketa River. Backbone Lake, a manmade “impoundment,” is four miles downstream from where the plant dumps its treated wastewater into the river.