It is hereby declared, as a matter of legislative determination:

(1) That the lands of the state of Washington are among the basic assets of the state and that the preservation of these lands is necessary to protect and promote the health, safety, and general welfare of its people; that improper land-use practices have caused and have contributed to, and are now causing and contributing to, a progressively more serious erosion of the lands of this state by wind and water; that the breaking of natural grass, plant, and forest cover have interfered with the natural factors of soil stabilization, causing loosening of soil and exhaustion of humus, and developing a soil condition that favors erosion; that the topsoil is being blown and washed off of lands; that there has been an accelerated washing of sloping lands; that these processes of erosion by wind and water speed up with removal of absorptive topsoil, causing exposure of less absorptive and less protective but more erosive subsoil; that failure by any land occupier to conserve the soil and control erosion upon his or her lands may cause a washing and blowing of soil from his or her lands onto other lands and makes the conservation of soil and control of erosion on such other lands difficult or impossible, and that extensive denuding of land for development creates critical erosion areas that are difficult to effectively regenerate and the resulting sediment causes extensive pollution of streams, ponds, lakes, and other waters.

(2) That the consequences of such soil erosion in the form of soil blowing and soil washing are the silting and sedimentation of stream channels, reservoirs, dams, ditches, and harbors, and loading the air with soil particles; the loss of fertile soil material in dust storms; the piling up of soil on lower slopes and its deposit over alluvial plains; the reduction in productivity or outright ruin of rich bottom lands by overwash of poor subsoil material, sand, and gravel swept out of the hills; deterioration of soil and its fertility, deterioration of crops grown thereon, and declining acre yields despite development of scientific processes for increasing such yields; loss of soil and water which causes destruction of food and cover for wildlife; a blowing and washing of soil into streams which silts over spawning beds, and destroys water plants, diminishing the food supply of fish; a diminishing of the underground water reserve, which causes water shortages, intensifies periods of drought, and causes crop failures; an increase in the speed and volume of rainfall runoff, causing severe and increasing floods, which bring suffering, disease, and death; impoverishment of families attempting to farm eroding and eroded lands; damage to roads, highways, railways, buildings, and other property from floods and from dust storms; and losses in navigation, hydroelectric power, municipal water supply, irrigation developments, farming, and grazing.

(3) That to conserve soil resources and control and prevent soil erosion and prevent flood water and sediment damages, and further agricultural and nonagricultural phases of the conservation, development, utilization, and disposal of water, it is necessary that land-use practices contributing to soil wastage and soil erosion be discouraged and discontinued, and appropriate soil-conserving land-use practices, and works of improvement for flood prevention of agricultural and nonagricultural phases of the conservation, development, utilization, and disposal of water be adopted and carried out; that among the procedures necessary for widespread adoption, are the carrying on of engineering operations such as the construction of terraces, terrace outlets, check-dams, desilting basins, flood water retarding structures, channel floodways, dikes, ponds, ditches, and the like; the utilization of strip cropping, contour cultivating, and contour furrowing; land irrigation; seeding and planting of waste, sloping, abandoned, or eroded lands to water-conserving and erosion-preventing plants, trees, and grasses; forestation and reforestation; rotation of crops; soil stabilizations with trees, grasses, legumes, and other thick-growing, soil-holding crops, retardation of runoff by increasing absorption of rainfall; and retirement from cultivation of steep, highly erosive areas and areas now badly gullied or otherwise eroded.

(4) Whereas, there is a pressing need for the conservation of renewable resources in all areas of the state, whether urban, suburban, or rural, and that the benefits of resource practices, programs, and projects, as carried out by the state conservation commission and by the conservation districts, should be available to all such areas; therefore, it is hereby declared to be the policy of the legislature to provide for the conservation of the renewable resources of this state, and for the control and prevention of soil erosion, and for the prevention of flood water and sediment damages, and for furthering agricultural and nonagricultural phases of conservation, development, utilization, and disposal of water, and thereby to preserve natural resources, control floods, prevent impairment of dams and reservoirs, assist in maintaining the navigability of rivers and harbors, preserve wildlife, protect the tax base, protect public lands, and protect and promote the health, safety, and general welfare of the people of this state. To this end all incorporated cities and towns heretofore excluded from the boundaries of a conservation district established pursuant to the provisions of the state conservation district law, as amended, may be approved by the conservation commission as being included in and deemed a part of the district upon receiving a petition for annexation signed by the governing authority of the city or town and the conservation district within the exterior boundaries of which it lies in whole or in part or to which it lies closest.