My town in MD does not have the traditional underground sewer system that I had growing up in NJ. Rather, it has drainage swales in front yards that slope downhill for rainwater. Underneath driveways there are metal culverts. I noticed that my culvert has rusted/rotted away on the bottom part of the high side of the driveway. I really don't want to pay to replace it, which would also entail a new driveway (or at least part of a new driveway). It seems to have its integrity and the driveway is not affected. Is there a way to repair the existing culvert? Perhaps add a plastic liner to it? Thanks.