Internal Navigation. 147 



and the 14 year floods, have been 22 feet perpendicular 

 above low water. I am well satisfied by experience, 

 that it' all the rocks and ob tructions were cleared out of 

 the natural channel of the Delaware, that three feet perpen- 

 dicular above low water, would be sufficient for raft na- 

 vigation. 



The mode of regulating the quantity of water is as 

 follows. — On the heads of those rivers, and on all the 

 streams above the Blue Mountain that feeds them, are 

 very large ponds or lakes, one above another. All of 

 such lakes that I have examined, appear to empty out 

 through deep narrow channels ; and I have been of 

 opinion, that they were formerly more deep and large 

 than at present, and that the channels have worn with 

 time. My plan is, to make dams on the outlets of all 

 the ponds, 10 or 12 feet, and in some places, more feet 

 in height ; and retain the water in high freshes, to draw 

 off and supply the rivers in any such proportions as oc- 

 casion may require to continue them navigable all 

 summer. In the winter, when the nav gation is ob- 

 structed by ice, let them all be shut, and the water reser- 

 ved until spring. 



I have long considered the subject, and sought for 

 certain data in vain ; that it is rather an estimation. I 

 have considered that the quantity of water, that runs 

 down either of these rivers, is in due proportion to the 

 extent or surface of country on which the rains and 

 snows that fall, drain into them ; then on what propor- 

 tion of the surface of ground that supplies these rivers 

 would the waters descend or drain into ^ch ponds or 

 lakes. I should think 2 thirds the water ; and I believe 



