OCR Text |
Show to a complete water resources development on the Columbia. The Situation Land development is proceeding at an accelerat- ing pace in the Columbia Basin. Almost 16 mil- lion acres of land are now in crops. New lands are constantly being brought into production, both dry farmed and irrigated. Of the total agricultural area, some 5 million acres are of such character and quality as to need relatively little more than good management to con- tinue in cultivation indefinitely. The balance, over 10 million acres, are of such character that they can be continued in cultivation only with care and attention. Most of them are subject to damage and should receive special attention. Evidence obtained from some of the currently irrigated lands shows that the retrogression found in other irrigated lands is already developing in some parts of the basin, although this is relatively a new area. Soil fertility is declining under use. The removal of the fines and other soil material by ditch irrigation also presages a future declining natural productivity. In addition, in some areas alkali conditions prevail. Substantial shifts, therefore, will be necessary to adjust present use to land capabilities. It is esti- mated that nearly 2 million acres of present crop- lands should go out of cultivation, and of these about 1.5 million should go into grass. About 75 percent of the presently irrigated lands must be improved to maintain fertility and reduce erosion. Of the 135,000 farms in the basin, conservation plans have been prepared for only 14,000. As an indication of the need for land conservation work, only 35 percent of the lands now irrigated are suitably leveled; only 25 percent of the lands need- ing drainage are drained; only 3 percent of the ter- races needed have been constructed. The Columbia Basin range today is overstocked. The effect of this is only recently coming to light as erosion is accelerating on the open range, of which 34 million acres is non-Federal, and about 55 million Federal land. Deterioration of this land has become serious. Although these lands are drier and perhaps less sub- ject to erosion, overgrazing is extensive, and in some areas has been the primary cause of serious erosion. It is estimated that about half of the pri- vate range land and perhaps two-thirds of the public lands (State, Indian, and Federal) are de- teriorating. The basin contains 59 million acres of forest land, about 42 percent of the total area of the United States part of the basin. Large areas of forest, particularly in Idaho and Montana, have been converted to worthless brush by fires in the past 50 years. Logging followed by fire has also been destructive in parts of the basin. Grazing in forest areas has been destructive of young growth and is adversely affecting future timber growth potenti- alities, besides increasing the erosion started by logging. Fortunately, the character of the soil and the climate in this basin are such as not to result in widespread erosion and extensive gullying such as have characterized depletion in other forest re- gions. However, in some sections following fire a large amount of material has been carried into the channels. Also, methods of logging and road con- struction in rough terrain are creating additional sedimentation problems. The use of streams for log transportation also has made them less habitable for fish. The effect of forest denudation has had the gen- eral effect of speeding up the melting of snow at the higher elevations. This has resulted in releas- ing snow water earlier in the melting season, and in greater volume in the first part of the melting period than otherwise would prevail. Conclusions In view of the retrogression on the irrigated, dry- farm, range and forest lands, and in view of the expanding land use economy of the basin, a water- shed program, integrated with other phases of water resources planning, is needed. A develop- ment plan is needed that will not only prevent the further deterioration of the water and soil resources, but will maintain their full productivity. Al- though steps are being taken in this direction, in view of the great activity in major construction projects, land treatment programs are not keeping pace with other plans of development or with the need. The watershed management program currently in operation in the basin is inadequate to cope with the expanding problem and appears to be losing ground in view of the rapidly expanding economy and changing land conditions. A land program is needed to insure continued productivity on Federal 59 |