L. MECHANICS AND ENGINEERING. 477 



At an early stage in the deliberations it was decided that, 

 although the judicious use of artificial reservoirs in moder- 

 ating the destructive effects of rivers had its advantages, yet 

 first, this method of protection against overflow was inap- 

 plicable to the lowlands of the Mississippi ; second, that no 

 reduction in the height of the floods of the Mississippi can 

 be obtained by diverting any of its tributaries from their 

 present channels ; third, that the local benefit above their 

 sites which results from cut-offs is more than counterbalanced 

 by the injury sure to result below in an increased flood-level 

 and caving of the banks ; fourth, that outlets of limited ca- 

 pacity, merely sufficient to reduce the flood-level a few feet, 

 would be advantageous, provided a free channel to the Gulf 

 could be found for water so abstracted from the river; fifth, 

 that the expedient of withdrawing water from one part of 

 the river to be subsequently returned below is sufficiently 

 dangerous to be adopted unwillingly, and only as a choice 

 of evils; sixth, that as all cultivation of the Mississippi bot- 

 tom-lands owes its success to the construction of levees, the 

 committee has confidence that the system properly applied 

 is adequate to the protection of the country against floods. 

 Whether it should be exclusively trusted, or be combined 

 with outlets, is a matter to be decided by economical consid- 

 erations. 



The committee also decided that all openings for over- 

 flows previously existing should be maintained, and that 

 one of these outlets (the Bayou Plaquemine) having been 

 closed, it should be reopened, provided it can be done with- 

 out danger of a disastrous enlargement. 



A general levee system extending from the head of the 

 alluvial basin to the Gulf, which shall likewise include val- 

 leys of the tributary streams, should also be established. 

 They estimate the total area of the bottom-lands to be about 

 32,000 square miles, of which but a trifling strip has hereto- 

 fore been available for agricultural purposes. Should the 

 recommendations of the commission be carried into practice, 

 it is estimated that it would reclaim and make available not 

 less than 2,500,000 acres of sugar land, 7,000,000 acres of 

 unsurpassable cotton land, and 1,000,000 acres of corn land 

 of the best quality. The estimates of cost, etc., which are 

 given as simply approximations, speak of 115,000,000 cubic 



