I have not personally had to manage this, but was at a conference some time ago where a workshop focused on TMDLs and the subject watershed had a fecal coliform impairment:
I've got a project right now that's at an industrial facility, where a pollutant containment pond (which also catches stormwater) had a FC impairment. We're working on a design to turn it into 100%(ish) retention and on-site treatment. Not sure that helps your question though.
Hydrology, Drainage Analysis, Flood Studies, and Complex Stormwater Litigation for Atlanta and the South East -
I would contact your Local USDA/NCRS office. They specialize in agricultural waste management. I used to work for them many moons ago. We never used channels for management. We did use waste retention ponds where you stored the waste and used a grinder pump to pump the sludge into a tank on a tractor where it was applied to agricultural fields. if the solid have been removed, you can spray irrigate the effluent. Google Living Filter. Hope this helps.