THE RIVER FISHERIES OF MAINE. 675 
river beds in the western part have a slightly steeper incline, and some in the eastern a more 
moderate one. The declivity is in general well distributed through the course of the river, but is 
in nearly all cases greatereat a distance from the sea, and its uniformity ig much broken by the 
occurrence of abrupt falls and lakes. The falls are not often precipitous or sufficient to prevent 
the ascent of fish, though this sometimes occurs, as at Hiram on the Saco, East Rumford on the 
Androscoggin, and on several tributaries of the Kennebec. 
' LAKES.—The great number of lakes that dot the surface of the State forms a striking feature 
in its topography. On the published maps there are represented 1,620, varying in size from 100 
acres to 120 square miles, and it is probable that several hundred more above the minimum in 
size are unrepresented. Their depths are in no known case very great, but few of them exceed 
100 feet, and many with an area of several square miles have in no place a greater depth than 
50 feet. One of the deepest is Lake Sebago, which has in one spot 410 feet of water. The 
lakes exert a favorable influence on the rivers as homes of migratory fishes in various ways. They 
serve as regulators of volume, preserving from extreme low stages, and as clarifying basins in 
which the sediment borne by the tributary streams is deposited. They afford breeding grounds 
for alewives and possibly retreats for salmon during the summer preceding and the winter follow- 
ing their spawning season. 
RIVER BEDS.—The stony character of most of the soil of Maine and the rapid flow of the 
rivers combine to give the latter in general a clear hard bed of rock in situ, or of bowlders and 
gravel, with, however, occasional stretches of muddy bottoms and banks. 
In the western part of the State the lowland adjoining the rivers is often composed of sand, 
which in that case forms the banks and sometimes part of the river bed. As a whole these rivers 
abound in the gravelly rapids to which salmon resort for spawning purposes. 
* PURITY OF WATER.—There is in the soil of the State comparatively little material that is 
readily taken up and held long in suspension by the streams and rivers. The occasional turbidity 
following a sudden and excessive fall of rain in the disforested districts soon disappears through 
the precipitation of the earth in suspension. The lakes also are immense clarifying basins, and 
discharge waters of great purity. The waters are, in most cases, strongly tinged with brown from 
peaty or earthen solutions, and the general color of the water, both of rivers and lakes, when seen 
in great depth, is an inky blackness, though when examined in a small receptacle, as in a goblet 
or pail, they appear of crystal purity. 
VoLumME.—Of the total rainfall it may bé assumed that 65 per cent. is evaporated and the re- 
maining 35 per cent. is discharged by the rivers into the ocean. This calls for a mean delivery of 
67.44 cubic feet of water per minute (35,452,000 cubic feet per annum) for each square mile of area 
drained. Applied to the Penobscot, this ratio indicates a mean discharge of 498,000 cubic feet per 
minute. « 
The fluctuations in the volume of a river are governed by several circumstances, of which we 
may mention, first, the irregularities of precipitation; second, the variation of the evaporation with 
the changes of weather and the season; third, the area of storage basins in the shape of lakes, and 
the extent to which they are brought into use. Many rivers of the second class have such exten- 
sive storage basins that the volume is very constant, the variations of level rarely exceeding 2 or3 
feet. But on the Kennebec and Penobscot a variation of 8 feet within four months is not very 
rare, and a difference of 6 or 7 feet between flood and drought is the rule. For instance,* on the 
*These data are furnished me by Mr. W. W. Fellows, engineer in charge of the water works, from personal 
observations. : 
