Kansas is preeminently an agricultural state. According to the United States census of 1910, the area in farms was 43,384,799 acres, or 67,789 square miles, 83 per cent of the total area of the state —82,158 square miles.

The products of these farms rank high in value among those of farms in other states, as shown by comparative statistics compiled by the United States Department of Agriculture, Bureau of Crop Estimates. For the period from 1913 to 1917 Kansas ranked ninth of the states of the United States in the value of all crops raised, exclusive of livestock; in 1919 Kansas ranked fifth. In livestock Kansas ranked sixth in 1918 and eighth in 1919.

Climatic conditions have largely dominated agricultural development in Kansas. Early ventures in dry farming in western Kansas, encouraged by a succession of rainy seasons, resulted in disheartening disasters, due to the dry seasons that followed. Throughout that region the farmers have gradually utilized the surface and underground waters for irrigation to provide against this deficiency of rainfall.

The floods that have occurred in the valleys of eastern" Kansas at frequent intervals during the past twenty years have been the subject of much investigation by state and Federal organizations. In 1844 and 1903 exceptionally disastrous floods occurred in the Kansas (Kaw) valley. Floods that were of lesser magnitude, but that caused widespread loss and injury to property, have occurred in other years, the most recent being the flood of 1915. Much of the cultivated land in these valleys lies along fertile river bottoms that are annually liable to overflow, and the control of the flood waters on these rivers and their tributaries is therefore one of the problems arising from unfavorable climate that demand early solution.

In view of the increasing demand for water for domestic service and fire protection, the need of determining whether the supply is adequate for rapidly growing centers of population throughout the state has recently been impressed very strongly upon a great many communities. The dependability of available sources of water supply during seasons of drought is fully as important as investigations of flood problems.

Practical solutions of the many local and statewide water problems, such as flood protection, flood prevention, domestic water supply, drainage, irrigation, and water power, depend largely on a thorough knowledge of certain physical data relating to water resources.

Hydrologic conditions differ widely in the different drainage basins, so that long-time investigations of stream-flow phenomena in each basin, as well as long-time investigations of meteorologic conditions over the state, are essential in the formulation of comprehensive plans to meet specific water problems.

The collection of long-time records of stream-flow in Kansas which is published in this volume has been prepared for the use of those who are concerned with the different phases of the utilization of water in the state.