Ag lime can be placed in the watershed (creek or spring) and wash in. It is better to have the spreader truck disperse it from the dam if that is the only location. I would use the liquid lime as a last resort. You can use pelletted lime in bags (not hydrated lime) which can be poured out of a boat or spread in shallow water at the edge. Take a look at this for why lime (alkalinity) is important. It has many benefits to water quality.

http://srac.tamu.edu/tmppdfs/144249-464f...80414f978c6b159