Biological Survey — Oswego Watershed 85 



Toward the north however, the country becomes more flat, and is 

 drained largely by less rapid streams. Although a high plateau 

 is to be found north of Oneida lake, even here the descent is gener- 

 ally more gradual than it is in the region of the Finger lakes. 



There are many lakes and ponds throughout the Oswego water- 

 shed. These tend to prevent floods in the streams which they sup- 

 ply by acting as temporary storage basins. Because of this fact the 

 Oswego river is much less subject to excessive high water, as is 

 emphasized by G. W. Rafter in his work on the Hydrology of New 

 York State (p. 110). 



This author gives much important data about the Oswego water- 

 shed which may be summarized, in part, as follows: Total catch- 

 ment area 5,002 square miles; total area of water surface approxi- 

 mately 310 square miles; total area of water surface, flats and 

 marsh, 530 square miles (10.6 per cent of total catchment area) ; 

 mean annual rainfall 30 to 40 inches; evaporation approximately 

 28 inches; annual runoff, calculated from a mean annual rainfall 

 of 36 to 37 inches, not more than approximately 9 or 10 inches; 

 highest waters (Fish creek region) about 1,800 feet above tide 

 level; lowest waters (at Oswego) about 400 feet above tide level. 



Distribution of Fish in the Watershed. — The problem of the 

 distribution of the various species of fishes throughout this large 

 area is not capable of being entirely solved. There are too many 

 factors to be taken into consideration. Not only would we need 

 to understand perfectly the geologic history of the area but also 

 must we consider the many changes brought about by mankind in 

 clearing the forests, polluting the streams, building canals and 

 otherwise disturbing the natural fish fauna. However it may be 

 of interest to note a few facts that are apparent in regard to the 

 question of distribution. 



(1) There are generally more species of fish in the lowland 

 where there are more gradual watercourses, than in the highland 

 where there are more precipitous ones. The tributaries of the 

 Finger lakes are poorer in number of species than are their outlets 

 and conversely, the northern area of the watershed is, as a whole, 

 richer in this respect than is the southern. 



(2) The headwaters of some streams of the Oswego drainage 

 have their sources very near others of either the Susquehanna, 

 Mohawk, Lake Ontario or Genesee watersheds and in certain cases 

 have acquired species of fish from the neighboring drainages. 

 This has occurred either by means of a former, natural, direct 

 connection or by a recent artificial one. 



The first case is illustrated by upper Buttermilk creek (Cayuga 

 lake drainage), which has its headwaters in close proximity to 

 those of Danby creek (Susquehanna drainage) and, judging by the 

 similarity of the fish fauna of the two streams, was once connected 

 with this creek. 



An example of the second case is shown in Catherine, creek 

 (Seneca lake drainage), which was joined with the Susquehanna 

 stream system by an artificial canal, which allowed certain fishes 



