Remember the golden rule on spreading manure: do not let it reach surface waters. This can be achieved by the best decisions you can make based on weather, rates, application methods and field conditions.
The basics for surface applied unincorporated manure are, the applicator should observe a minimum of 150 foot setback from surface waters, including ditches and areas subject to flooding. If conservation measures, such as, vegetative buffers are in place they may be sufficient to protect surface waters from runoff.
Following these recommendations will help achieve conformance with right to farm guidelines and provide nuisance protection. But they do not over ride common sense.