July 10, 1914] 



SCIENCE 



45 



confined to efforts to protect the banks of the 

 river from overflow. In this the levees have 

 failed. For although the government appro- 

 priates millions of dollars for such work, we 

 nevertheless continue to have floods, causing 

 the loss of many lives and the destruction of 

 property valued at more than 100 millions of 

 dollars a year averaged over a ten-year period. 

 This levee system has also been tried on the 

 Hoang Ho in China for thousands of years, 

 and has failed there. 



In this country the damage done by floods 

 has been appalling. You remember well what 

 happened at Dayton, Ohio, this year. You 

 remember the photographs showing the terrible 

 conditions in that city. The same conditions 

 have caused heavy damage in other years, at 

 other places. Pittsburgh, Cincinnati, Mem- 

 phis, New Orleans, have all suffered. These 

 cities are all in the Ohio and Mississippi 

 Eiver basin. Other rivers have overflowed 

 and caused great damage without attracting 

 so much attention. 



The government by allowing flood waters to 

 accumulate and rush towards the sea during 

 the season of freshets and melting snow per- 

 mits the food-producing power of the country 

 to be reduced. This reduction results from 

 three different processes. 



First : The upland is robbed of moisture 

 that is greatly needed by maturing crops. 



Second: An. enormous amount of valuable 

 top-soil is lost by erosion. 



Third: The lowlands are drowned. While 

 the lowlands are much less in area than the 

 uplands, their possible producing power is far 

 greater per acre. In fact, they are the richest 

 lands in the world. The loss from erosion 

 is beyond computation. 



Under the present policy of building levees 

 only it is admitted that the banks of the 

 Mississippi between Cairo and Donaldsonville 

 cave in each year to the extent of 9J acres a 

 mile for a distance of nearly 1,000 miles. Each 

 year, therefore, nearly 10,000 acres of the best 

 land in the world is deliberately surrendered to 

 the floods. Engineers when building the 

 levees place them back as far from the edge 

 of the river as they think will be necessary to 

 last 15 or 20 years. Is that a business-like 



proposition ? It is estimated that 1,250,000,000 

 tons of silt are deposited annually in the 

 Mississippi River. Of this amoimt 600 million 

 tons flow out through the mouth of the river 

 and 650 million tons remain to fill up the 

 channel. This 650 million tons is 2^ times the 

 amount excavated in digging the Panama 

 Canal. 



It should be borne in mind that this enor- 

 mous damage by soil erosion applies not only 

 to the farms that lie adjacent to our great 

 rivers, but that a very larger percentage of 

 the six million farms in the United States 

 suffer great losses from soil erosion, and a 

 consequent decrease in production. It should 

 also be noted that under the present methods 

 the navigation of the rivers in the upper 

 reaches is almost impossible during the sea- 

 sons of drouth. In fact, there are times when 

 there is scarcely enough water for sanitary 

 drainage. The storage reservoir system would 

 assure navigation throughout the dry season. 



The facts and figures above quoted show 

 how important it is to conserve all precipita- 

 tion. That this can be done has been conclu- 

 sively demonstrated in diilerent sections of the 

 country. Col. Freeman Thorpe, of the Min- 

 nesota Horticulture Society, who owns a large 

 experimental farm near the headwaters of the 

 Mississippi River, has allowed no water to run 

 off his farm for 17 years. His farm consists 

 of cultivated land, pasture and forest. His 

 methods are extremely simple and inexpensive, 

 consisting chiefly of contouring and embank- 

 ment work, the effect of which has been to 

 double the annual growth of trees in his 

 forest, more than double the capacity of the 

 grazing land, and add largely to the produc- 

 tivity of the cultivated land. 



Col. Thorpe declares that there are over 

 SOO million acres of land now idle on the 

 great central plateau of the United States for 

 the want of sufficient rainfall. This, he says, 

 would be the best soil for scientific farming, 

 if we compelled the filtration into the soil of 

 all the limited precipitation. In other words, 

 if the actual precipitation were conserved all 

 this land would be available. Professor Waite, 

 of the Department of Agriculture, owns a 

 farm between Washington and Baltimore, 



