It is not the mission of this book to prescribe plans for meeting the situation. That must be the work of a corps of trained engineers who shall study the whole problem comprehensively and in detail. Rather it is our purpose here to bring home the overwhelming need for prompt action. We may be permitted, however, to point in a general way, and on high authority, the general lines that the necessary remedies must take.
The river problems in the great central valleys present certain difficulties which engineers have been unable to overcome. If levees are constructed, it is found that the bed of the stream rises also, so that the situation is not materially changed. If channels are deepened, the fury of the floods is increased. If the construction of reservoirs is proposed, there are very important questions of location and danger.
UTILIZING NATURAL RESERVOIRS
In many places the Mississippi River, closely diked, flows high above the lands adjacent. Even at New Orleans, 107 miles from the Gulf, it is during high water ten to fifteen feet above the level of the city. Obviously the levee system, while useful everywhere and in some localities adequate, is not a universal remedy. Reservoirs properly constructed should be of service in storing the waters of many such rivers as those that have caused the havoc in Ohio and Indiana, but to meet the requirements they would have to be of enormous size, very numerous and costly, as Professor Willis S. Moore, chief of the Weather Bureau, points out.
Nature itself has provided in lowlands throughout all of these valleys receptacles which, before men came, took up the surplus waters. We have reclaimed millions of acres of these lands on the theory that we could confine the rivers which once overflowed them, but thus far we have failed to establish the theory.
It is probable that any successful national work for the control of rivers will have to start with the idea of utilizing some of these natural reservoirs. The lands would not be habitable of course, but for agriculture they would be enriched instead of, as now, devastated. To depopulate some such tracts would not be as costly or as terrible as to leave them to the sweep of irresistible torrents, repeated year after year.
PROMOTION OF FORESTRY
Despite Professor Moore's very positive denial of the value of reforestation as a preventive of floods, it is claimed by many authorities that much of the destruction is due to the fact that the states of Ohio, Indiana and Illinois have been almost denuded of such forests as originally stood there. No impediment is offered to the flow of water and disastrous results follow. But in any event there would have been great floods because of the location of the rainstorms as noted.
CONSTRUCTION OF DAMS
The topography of the country must be taken into account. Both valleys, the Miami particularly, are veined with streams tributary to the rivers, and in times of flood the water rises with amazing rapidity and spreads far and wide over the valley floor. The level character of the region in which Dayton itself lies and the fact that there is not enough pitch to the land below to carry off the water accounts for the depth and extent of the floods. Dayton has had many of them. What Congress can do to prevent or minimize them in future by putting the army engineers at work to construct dams for the collection and restraint of waters in the valleys north of the threatened cities must be done, whatever the cost.