Downstream natural areas as refuges for fish in drainage-development watersheds

Agricultural drainage development in southwestern Minnesota involves installation of tiles to drain subsurface waters, creation of tributary ditches, and channelization of existing streambeds. The presence, abundance, and diversity of fishes collected in downstream unmodified areas of drainage-developed and undeveloped streams indicate that any downstream impacts are much less severe than impacts demonstrated by others within developed areas. These natural areas appear to serve as reservoirs for stream biotas and should be preserved as refuges for fish species inhabiting those streams.