Some of the more deeply cut stream channels are as low as 200 m above sea level. Most of the outer part of the Basin is deeply dissected and consists of steep slopes between narrow rolling ridgetops and narrow valleys. The inner part of the Basin is predominantly undulating and rolling. In many places the land surface is deeply pitted by limestone sinks, and outcrops of limestone rock are almost everywhere. Average annual precipitation -About 1,275 mm.
Maximum precipitation is in midwinter and early in spring, and the minimum is in autumn.
The temperature varies little throughout the Basin. The moderately high precipitation generally provides adequate moisture for crops and pasture, but in some years, short periods of drought in summer reduce pasture and crop yields. Permanent streams and lakes are an important source of water. The Cumberland River has dams for flood control, power production, navigation, and recreation. Ground water from wells and springs is an important source of water for domestic use and for livestock.