Many native animals live underground as a way to adapt to the harsh arid climate. The eastern boundary of the High Plains is often cited as the 100th meridian or the 600-m contour or elevation line. But prairie vegetation boundaries are flexible, advancing or retreating in response to the weather. Located in the rain shadow of the Rocky Mountains, the High Plains is semi-arid, with precipitation averaging less than 50 cm per year. Because of its location, the High Plains is subject to climatic extremes.
Rivers are few, and the waters they contain are high in demand.
Additional water can be found in several underground aquifers. The Ogallala Aquifer, North America's largest underground water source, lies beneath the western parts of Nebraska, Kansas, and Oklahoma, extending north into South Dakota, west into Wyoming and Colorado, and south into New Mexico and Texas. These aquifers are like huge underground sponges made of porous sediments of sand and gravel eroded from the Rocky Mountains. Less permeable sediments underneath the aquifers hold the water in place. Let us know of wheel chair accessible areas in our Natural Environs for enjoyment by persons using wheel chairs, as it is has been very difficult for me to get my Dad to many of the interesting places that most of us walk into.