456 GEOLOGY OF OHIO. 
level of the canal without any advantage to the canal. It is equally true 
that a much greater proportion of it could be utilized than actually finds | 
its way into the canal—enough, certainly, to remove the question of the 
supply of water out of the discussion concerning the abandonment of the 
canal. | 
THE LORAMIE RESERVOIR. 
This body of water, covering at present but little over 2000 acres 
of land, lies wholly in Shelby county, and although not one of the 
largest of the State reservoirs, nor the most important, still it is ex- 
ceedingly valuable to successful navigation in the summer and early 
fall. The bottom of the reservoir is about eight feet above the sum- 
mit level of the canal. It is supplied by the drainage of about sixty- 
five or seventy square miles. Being near the water-shed, the surface 
from which water can be collected into the reservoir is limited, and less 
water comes from springs than would be the case in many other localities 
not so high. While the main reliance is on drainage from a limited sur- 
face, still such is the nature of the surface-soil, that a much larger pro- 
portion of the water which falls upon the surtace runs off at once than 
would run from soil of a more porous character, or one underlaid by 
large beds of clean gravel, or sand, or porous rock. The construction of 
roads, drains and ditches, as well as the clearing away of the timber and 
the cultivation of the soil, cause a more rapid flowing away of the water 
which falls upon the surface. Formerly the reservoir received more water 
from the gradual draining of the surface; this maintained it at a good 
stage for a longer time, and enabled it to furnish a greater supply during 
those months of the dry season when water is usually low in the canal. 
If the capacity of the reservoir could be increased so as to hold more of 
the water which falls in the winter months, its usefulness might be 
greatly increased, for instead of being maintained in good stage until 
late in the summer by the gradual running out of the water from the 
extensive swamps of an early day, it is now filled up by the rapid surface 
drainage, and to furnish as much water when most wanted must have a 
capacity to hold at once all that comes into it in the winter and spring. 
In 2000 acres of land there are 87,120,000 square feet. If it is filled, 
during the year, with eight feet in depth of water, there would be 
696,960,000 cubic feet; allowing that one-half is lost by evaporation, 
soakage and waste from imperfect bulkheads, there would remain 348,- 
480,000 cubic feet for the uses of the canal—enough to lock down, with 
the present size of locks, eighty boats from the summit level every day 
of the year. With sixty-five square miles of drainage, from which the 
reservoir must receive its supply, how much of the forty inches annual 
rain-fall would be necessary to furnish this amount? Less than five 
wt 
