Relation of Forestry to the Control of Floods in the Mississippi Valley: Message from the President of the United States, Transmitting Communications from the Secretary of Agriculture Submitting Reports with Reference to the Relation of Forestry to the Control of Floods in the Mississippi Valley |
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Page 5
... silt content . Dependable data on silt content were woefully lacking . Determinations made many years ago could not be checked against similar data of more recent date because recent measurements had not been made . A com- plete record ...
... silt content . Dependable data on silt content were woefully lacking . Determinations made many years ago could not be checked against similar data of more recent date because recent measurements had not been made . A com- plete record ...
Page 11
... silt content . Figures giving averages over long periods and for varying conditions of flow are obviously no index to actual silt content at flood crest , which is the critical point . Available data seem to indicate that the waters of ...
... silt content . Figures giving averages over long periods and for varying conditions of flow are obviously no index to actual silt content at flood crest , which is the critical point . Available data seem to indicate that the waters of ...
Page 24
... silt and freshet run - off contributed to the Mississippi River comes not from forest land , but from farm lands which are being unwisely used . The reports on the 6 major basins and the individual reports on the 73 drainage units ...
... silt and freshet run - off contributed to the Mississippi River comes not from forest land , but from farm lands which are being unwisely used . The reports on the 6 major basins and the individual reports on the 73 drainage units ...
Page 34
... silt from these lands fills the drainage canals on the lowlands ; not only is it important for the protection of the lowlands from silt and floods , but the protection of these lands is also vital to the future usefulness of the region ...
... silt from these lands fills the drainage canals on the lowlands ; not only is it important for the protection of the lowlands from silt and floods , but the protection of these lands is also vital to the future usefulness of the region ...
Page 38
... silt burden from our streams each year as a result of this 1926 expenditure , or slightly more than 9 tons of silt for each dollar originally expended . This would make the cost to the Federal Government of a single year's service less ...
... silt burden from our streams each year as a result of this 1926 expenditure , or slightly more than 9 tons of silt for each dollar originally expended . This would make the cost to the Federal Government of a single year's service less ...
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Common terms and phrases
acres agricultural alluvial amount annual precipitation Appalachian Plateau Appalachian Valley Arkansas River average Bad Lands belt bluffs bottom lands cent chert clay County critical areas crops cultivated Cumberland Plateau drainage area drainage basin drained eastern eroded erosion especially extensive farm feet fire flood plain flow forest area forest cover forest land formations glacial grass grazing gullying hardwood hardwood type headwaters heavy Highland Rim hills hilly humus inches Kentucky limestone litter loess lumbering mean annual Mississippi River Missouri Missouri River Mountains national forests occur Ohio Ohio River Oklahoma Ouachita Ouachita Mountains Ozark pasture planting plateau portion prairie present protective value province rainfall region result ridges River Basin River drainage rolling run-off sand sandstone sandy shale silt loam slopes soil southern square miles steep streams surface Tennessee timber tion topography trees tributaries upland hardwood upper valley washing watershed western wood lots woodland
Popular passages
Page 15 - No public forest reservation shall be established, except to improve and protect the forest within the reservation, or for the purpose of securing favorable conditions of water flows, and to furnish a continuous supply of timber for the use and necessities of citizens of the United States...
Page 89 - Mexico, to be completed within twenty years; of the Mississippi River between the mouth of the Missouri and the mouth of the Ohio River...
Page 39 - States, or, in his discretion, with other suitable agencies, to assist the owners of farms in establishing, improving, and renewing wood lots, shelter belts, windbreaks and other valuable forest growth, and in growing and renewing useful timber crops...
Page 4 - Then God. our Lord, hindered the work with a mighty flood of the great river, which, at this time, began to come down with an enormous increase of water, which in the beginning overflowed the wide level ground between the river and the cliffs; then little by little it rose to the top of the cliffs.
Page 4 - The flood was 40 days In reaching its greatest height, which was the 20th of April, and it was a beautiful thing to look upon the sea where there had been fields, for! on each side of the river the water extended over 20 leagues of land, and all of this area was navigated by canoes, and nothing was seen but the tops of the tallest trees.
Page 51 - Forest rehabilitation is not urged as an alternative to engineering works for flood control. It is supplementary to the engineering program, but it is a supplement of such importance that no complete plan of flood control can omit it. ACKNOWLEDGMENT Space does not permit the inclusion of the names of the various individuals and agencies who have contributed to this report. Such a list would be a directory of people interested in the conservation of forests, streams, and water resources generally...
Page 63 - C.) humus per 2| acres was determined. Allowing 15 per cent for excess moisture content of air-dried over ovendried humus, the air-dried spruce and beech humus were found to have a retentive capacity of approximately 46.44 and 22.2 tons of water per acre, respectively. This amounts in volume to 1,510 cubic feet per acre for spruce and 712 cubic feet for beech humus, equivalent to a rainfall of 0.41 inch and 0.2 inch, respectively. The depth. of soil has a bearing upon the amount of water which it...
Page 8 - ... torrent of twenty miles an hour will carry boulders weighing one hundred tons. It is a self-evident fact that water falling on steep lands tends to rapid runoff. The laws just cited show that erosion is tremendously increased by rapidity of runoff. It follows that for any given type of soil the steepest lands are most subject to erosion. Therefore it is upon steep rough lands that forests as an erosion-preventive factor are most important. Coincident with retarding erosion and runoff, forests...
Page 404 - The rains run off, therefore, into the streams very quickly producing very sudden rises and floods. In dry weather as there is little or no ground water stored, the flow of the stream becomes very small and in some places dries up entirely. The banks of the river are low and in times of floods large areas are covered with water, delaying the planting of crops and at times destroying growing crops.