Field Trip

James S. Aber
EB/ES/GE 351

Table of Contents
Introduction Dunlap
Lake Kahola References


Dunlap and Kahola are located at the eastern edge of the
Flint Hills physiographic region. The eastern margin of the Flint Hills is marked by a major escarpment, maximum elevations exceed 500 m, relief is locally up to 100 m, and stream valleys are deeply entrenched. From their eastern crest, the Flint Hills slope gently westward, following the regional bedrock dip.

Locality map for Dunlap, Kahola and surrounding features in Lyon, Chase, and Morris counties. The eastern margin of the Flint Hills is marked by the heavy line (* Neva Limestone). RNHR = Ross Natural History Reservation, KDR = Kansa Diminished Reserve. Adapted from Aber (1990).

The Flint Hills are underlain by lower Permian limestone, shale and evaporites. This bedrock generally dips gently toward the west or northwest. Local variations in bedrock dip are found over the crest of the buried Nemaha uplift and Humboldt fault zone. Erosion of interbedded shale and limestone strata has resulted in landscapes with steep east-facing escarpments separated by gentle west-sloping cuestas. Thick cherty limestone units weather to produce residual chert (flint) lag deposits that are highly resistant to chemical breakdown. Such residual chert is responsible for maintaining high topographic relief. Unconsolidated sediments are common, especially within river valleys and on some upland areas.

Ourcrops of the Wreford Limestone along US highway 56 east of Council Grove. Thick cherty limestone (left) and residual chert (flint) just below the surface (right). Photos © JSA.

The Flint Hills region receives ample rainfall, about 32 inches (80 cm) average annual precipitation. The Flint Hills are, in general, a region of water surplus; water leaves the region via many surface streams and by subsurface migration. Ground water is readily available throughout the Flint Hills region, as witnessed by artesian wells and numerous large and small springs. Ground water of the Flint Hills region generally has high total dissolved solids and high total hardness concentrations.

Flint Hills water resources. Left: watercress growing in a spring, central Chase County. Right: artesian well produces sulfur water in Marion County. Photos © JSA.

The Flint Hills include the largest tract of tallgrass prairie that still exists in the United States. Owing to rocky soils and steep slopes, crop agriculture has been limited to alluvial soil in valleys, particularly in the eastern portion. Cattle grazing is the primary land use, and ranchers employ controlled burning to maintain the prairie grasses (Hoy 1993). The Flint Hills embody the archetype of the American prairie, and as such the region has become a destination for ecotourism and scientific research.

Typical spring views of the tallgrass prairie in Chase County. Kite aerial photograph of Flint Hills upland (left) and ground shot of cattle grazing on open range (right). Photos © JSA.


The small town of Dunlap is located along the eastern edge of the Neosho River valley in southeastern Morris County. This vicinity witnessed two important chapters in the history of Kansas (Hickey 1990).

More about the Dunlap vicinity.

Lake Kahola

Lake Kahola is a relatively small, man-made reservoir located in the Flint Hills of east-central Kansas. Drought conditions in the early 1930s and severe water shortages for the city of Emporia were the reasons the city decided to build a reservoir on Kahola Creek. The dam was completed in 1937 at a cost of $290,000 (Aber 1990). The dam is 1900 feet long and up to 70 feet high. The spillway has an elevation of 1269 feet, and the lake covers approximately 400 acres (~160 ha) when full. In the past, the lake served as a reserve water supply for the city of Emporia.

The lake was developed early for summer cabins and recreation. Sixty cabin sites were established by 1944, and the lake became well known in the 1950s for sailing, water-skiing, swimming, and fishing. During the 1960s and 1970s, the recreational significance of the lake began to dwindle, however, with construction of large reservoirs in eastern Kansas by the U.S. Army Corps of Engineers. Lake Kahola now has approximately 200 cabin sites plus a year-round caretaker in residence.

Lake Kahola straddles the Chase-Morris county line, and an old Indian treaty boundary runs across the southern edge of the lake. Portion of the Lake Kahola, Kansas 7.5-minute topographic map (1972). Map obtained from USGS Store.

The name Kahola is derived from an Indian word meaning spring water. In fact, many springs feed the lake from its southern bluff due to local dip of bedrock toward the northwest. Because of this ground-water recharge, the lake is relatively drought resistant, in spite of having a relatively small drainage basin about 16 square miles (~40 sq. km). The drainage basin consists almost entirely of tallgrass prairie utilized mainly for cattle grazing, which results in excellent water quality in the lake. The upstream (western) end of the lake has developed into a wetland nature preserve, and strict regulations have kept out zebra mussels (Dreissena polymorpha) so far.

Through the twentieth century, building lots were leased from the city under a long-term arrangement with the Kahola Park Cabin Owners Association. Early in this century, however, the city began the complex legal process of selling the land to the cabin owners association. This sale was completed in 2007, when the renamed Kahola Homeowners Association (KHA) took private ownership of the lake and surrounding property.

Winter overviews of Lake Kahola
Left: toward the northeast showing the dam, spillway (sw), and outlet tower (ot).
Right: looking westward with partial ice cover. Kite airphotos © JSA (2014).

Over the years, development of cabin sites at Lake Kahola had proceeded in a somewhat piecemeal manner, which was aggravated by the lack of original survey markers. The existing plat of lease lots was a schematic blueprint chart of unknown age, which was not a legally valid survey. This problem had become exacerbated in recent years by the construction of increasingly large recreational homes and numerous garages, boathouses, docks, and other structures. Two issues were of primary concern: 1) wise management for future development, and 2) arbitration of disputes between adjacent lot owners.

Recognizing these issues, the cabin owners association began an effort in 2000 to place permanent survey markers at the corners of all building lots in the park. To supplement the ground-based survey markers and lot measurements, large-scale airphotos were selected as the tool for documenting lake-shore development and lot boundaries. Vertical kite aerial photography was conducted during the winter, leaf-off period in order to obtain views with minimal obstruction from trees (Aber and Aber 2003). Conducting vertical photography around an irregular shoreline proved challenging, especially in regard to numerous power lines, roads, fences and trees in vicinity of the buildings. Lot boundary markers were identified with additional ground survey.

Left: portion of the original plat of Lake Kahola cabin lots; a highly schematic diagram that lacks any georeferencing (date unknown). Right: actual lot boundaries marked by red dots annotated on a vertical kite aerial photograph. Adapted from Aber et al. (2010).

Recently a detailed bathymetric and sediment survey of Lake Kahola was conducted by the Kansas Biological Survey—see
Kahola survey. For elevation purposes a benchmark was established, as shown (Fig. 3), and sonar sounding was conducted from a small boat to determine water depth (Figs. 4 and 5). Maximum depth is 30-35 feet near the outlet tower at the southern end of the dam.

More about the Lake Kahola.


Return to course syllabus.
EB/ES/GE 351 © J.S. Aber (2014).