Whenever one or more municipalities may be situated upon or near a stream which is bordered by lands subject to overflow from natural causes, or which is obstructed by dams or artificial obstructions so that the natural flow of waters is impeded so that drainage or the improvement of the channel of the stream will conduce to the preservation of public health, such municipalities and the surrounding lands deleteriously affected by the conditions of the stream, may be incorporated as a sanitary drainage district under sections 31-501 to 31-523 in the manner following: Any one hundred legal voters, residents within the limits of such proposed sanitary drainage district, may petition the county board of the county wherein they reside to cause the question to be submitted to the legal voters within the limits of such proposed sanitary drainage district whether they will organize as a sanitary drainage district under such sections. In the case of municipalities of less than one thousand inhabitants, as determined by the most recent federal decennial census or the most recent revised certified count by the United States Bureau of the Census, two-thirds of the legal voters, residents within the limits of such proposed sanitary drainage district, may petition the county board of the county wherein they reside to cause the question to be submitted to the legal voters within the limits of such proposed sanitary drainage district whether they will organize as a sanitary drainage district under such sections, and if a majority of those voting on the question are in favor of the proposition the district shall be organized.