456 GEOLO&Y 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 disiassioQ concarning the abandonment of the 

 canal. 



THE LO RAMIE RESEEVOIE. 



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, nof 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 che 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 maay 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, th^t a much larger pro- 

 portion of the water which falls upon the siirlace runs ofi" 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 up^n 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 tl.e 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 



