The Kansas River Valley between Lawrence and Topeka is on the boundary between the Dissected Till Plains and Osage Plains sections of the Central Lowlands physiographic province as defined by Fenneman (1931). More recently Schoewe (1949) has placed the area entirely within the Dissected Till Plains section. Locally the most striking topographic feature is the broad flat east-west trending Kansas River Valley.
Kansas River Valley can be divided topographically into a low flat terrace and a channel-scarred flood plain. A natural levee at the margin of the terrace hinders drainage on a large part of the terrace surface. Drainage ditches have largely eliminated the marshes which once occupied the area between the natural levee and the river bluffs. On the flood plain many small ponds and marshes fill old meander scars and have not been drained extensively.
The Kansas River Valley is asymmetrical due to the river cutting almost exclusively on the south side. This southward cutting increases the gradients and hence the erosional power of small tributaries on the south, which in turn produces rugged topography adjacent to the river. North of the river lessened stream gradients combined with the presence of terrace remnants and glacial till produce a much more subdued topography.
Bedrock topography typical of eastern Kansas is well developed south of the river. Prominent east-facing escarpments and rock benches are produced by the resistant westward-dipping limestone strata.
The total relief of the area is slightly more than 330 feet, and the local relief is commonly between 100 and 200 feet. The hills south of Topeka are the. highest points in the area and have elevations in excess of 1,150 feet. The lowest point is along Kansas River in the eastern extremity of the mapped area.
The Kansas River Valley is included within the area having a humid continental type of climate. Warmest months are July and August which have monthly mean temperatures above 75° F. with daily maximums often in excess of 100° F. but rarely in excess of 105° F. Winters are generally mild with occasional cold waves during which the temperature drops, to between 10° F. and -5° F. for one to four days. The coldest month is January which has a mean monthly temperature of 29.9° F. in Lawrence and 29.4° F. in Topeka (Table 1). The mean annual temperature in the area is slightly more than 55° F. and the average length of growing season is about 195 days.
Table 1--Normal monthly precipitation and temperature at Lawrence and Topeka
|Temperature, degree F||Precipitation, inches|
Most of the precipitation is during the spring and summer months. The normal annual precipitation is 35.40 inches at Lawrence, 34.9 inches at Lecompton, and 32.58 inches at Topeka. The lowest known annual precipitation in the area is below 25 inches and the highest known annual precipitation is more than 50 inches. Figure 2 gives the normal monthly precipitation at Lecompton.
Figure 2--Graph showing normal monthly precipitation at Lecompton. (Data from U.S. Weather Bureau.)
The population within the mapped area is estimated from the 1948 census of the Kansas State Board of Agriculture to be about 130,000. The population of the larger cities and towns according to the 1950 census are: Topeka, 87,626; Lawrence, 18,638; Perry, 413; and Lecompton, 267. Towns which have stores and post offices but for which no population figures are available are Williamstown, Tecumseh, and Grantville. Other smaller communities are Kiro, Menoken, Midland, Big Springs, Newman, Thompsonville, and Lakeview.
The area is crossed in an east-west direction by main lines of the Union Pacific Railroad, Chicago , Rock Island, and Pacific Railroad, and the Atchison, Topeka, and Santa Fe Railway. Branch lines of the Union Pacific Railroad, Atchison, Topeka, and Santa Fe Railway, and the Missouri Pacific Railroad also cross the area in a general north-south direction. Several bus lines serve Lawrence and Topeka as well as intermediate points and air lines also serve Topeka.
The hard-surface highways passing in an east-west direction through the area are U.S. 40, U.S. 24, and K-10. The hard-surfaced highways through the area in a north-south direction are U.S. 59 which passes through Lawrence, and U.S. 75 which passes through Topeka. K-4 merges with U.S. 75 north of Topeka and is parallel to K-10 west of Topeka.
Corn is the principal crop raised in the area. Other important crops include wheat, oats, alfalfa hay, Irish potatoes, sorghum, soybeans, apples, and nursery stock. Much of the upland is used for grazing cattle, particularly land which is too stony or steeply sloping to be of other use.
Strawberries, garden vegetables, and nursery stock are the only crops which receive irrigation during years of normal precipitation. Generally, irrigation is most needed during the first two months of the growing season. Drought conditions could make irrigation desirable for other crops; however, few people maintain irrigation wells as insurance against dry years.
Food processing is the leading industry in the area with flour, meat, poultry, dairy products, and canned vegetables being the principal items produced. Other important industrial products are tires, locomotives, freight cars, bearings, farm machinery, dog food, sand and gravel, serum, crushed limestone, sheetmetal and foundry products, cardboard boxes, and silos.
Kansas Geological Survey, Geology
Placed on web April 10, 2012; originally published June 1, 1952.
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