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7 The most obvious and direct method of prevention of damage by floods is to move the dwellings and works at' man to higher ground out ot' the reach of high water. Another, and perhaps JIIOre economical, method of reducing the extent of floods and their resulting damage is through a land conserva- tion progr8l1l. Small erosion dams, reforestation, contour plowing, cover crops - all the ~ devices of the soil conservationist most effective~ reduce tha volUllle and height of floods. Adequate river channels and levees, where proper~ applied, are a simple and direct protection against floods and constitute a de- vice which has been wide~ and successf'ully used. The Mississippi is controlled entire~ by levee and channel improvements. Another practical way to reduce flood peaks is to increase- the alIIount of channel storage by the construction of retarding basins at suitable locations upstrealll from the area to be protected. These dallls, like the natural channel storage, hold back a portion of the water temporari~. This method has been used with great success on drainage areas of relatively limited extent. True retarding basins are formed by simple dams or barriers at suitable sites. Each dam is equipped with an outlet or slot, with- out gates or any other artificial means of controlling the flow. The outlet of the retarding basin is of such size that no more water can pass than the river channel below can carry. The basin acts just like a bath tub without the plug. Water will flow out of the tub or basin as fast as it comes in up to the capacity of the outlet. But if water enters at a faster rate, the drain will not carry all of it off, and the remainder backs up in the tub or reservoir, to be carried oft' gradually as the inflow is reduced or cut off. Except during the few days when water is backed up behind the dams, the basins are dry and their rich lands are farmed. Most floods occur before the growing season; there is no scour or erosion