ES 546 Project Summary

Kansas Playa Lakes
James S. Aber

Table of Contents
Introduction Methodology
2009 project Questions
References ES 546 syllabus

Introduction

From the glaciated district in the northeast to the High Plains of southwestern Kansas, the state contains a rich variety of geomorphic features, which reflect variations in erosional and depositional processes, climate, elevation, vegetation, underlying bedrock, and tectonic influences.

Shaded-relief topographic map of Kansas. Elevation ranges from less than 750 feet along the northeastern and southeastern edges to more than 4000 feet at the west-central margin.

Based on conterminous USA 30-sec digital elevation dataset from the NGDC (NOAA). Image processing with Idrisi by J.S. Aber.

Among the distinctive geomorphic features are enclosed drainage basins that contain ephemeral lakes. These basins range from a few hectares in extent to 1000s of km². Known as playas, this term refers both to the lake and the basin that contains the lake. Playas may hold water on a seasonal basis; some may remain dry for several years and then fill from an exceptionally heavy storm, snow melt, or wet year. Many playas are dry more often than wet. Thousands of playas exist throughout the central and southern Great Plains of the United States.

Playa Lakes Joint Venture--see PLJV.

SFAP methodology

Ground photography has long been utilized for depicting and documenting the natural landscape in Kansas (Landes 1935; Charlton and Merriam 2003). The primary method of study employed for this project is small-format aerial photography (SFAP). This technique is based on 35- and 70-mm film cameras or compact digital cameras to acquire airphotos from manned or unmanned platforms (Warner, Graham and Read 1996). Manned platforms include small airplanes and helicopters, ultralight aircraft, gliders, and hot-air balloons. Unmanned platforms in common use are balloons and blimps, model aircraft, and kites. SFAP has become widely employed in recent years for documenting all manner of natural and human resources (Bauer et al. 1997), including geology and geomorphology (Hamblin 2004). The method is relatively low in cost, highly portable, and quick to operate in the field.

At ESU, we have developed SFAP based on kites (Aber et al. 1999) and a small helium blimp (Aber 2004) for lifting various types of cameras. Since 2005, we use high-resolution digital cameras exclusively for color-visible and color-infrared imagery. Photographs are taken from 100-500 feet (30-150 m) above the ground using radio-controlled camera rigs. The camera may be tilted (vertical to horizontal) and rotated (360°) in order to provide all possible viewing angles in relation to the ground target. These photographic views bridge the gap between the ground and conventional airphotos or satellite images. Manned airplanes and helicopters normally are restricted to heights above 500 feet in the countryside and 1000 feet in urban areas. SFAP taken below 500 feet has large scale and exceptionally high spatial resolution (<5 cm) that depicts ground features in surprising detail.

Dry Lake, Scott County, west-central Kansas
As an introductory example, consider these two views of Dry Lake, a relatively large playa at the terminal point of an enclosed basin. Left: lake full of water following heavy winter snow and runoff, May 2007. Right: basin is a wet, salty mudflat in May of 2008. Kite aerial photos by JSA & SWA.

Great Plains aerial photography.

Course project

In Kansas, most playas are located in the High Plains and Arkansas River Lowlands as well as other physiographic regions of central and western Kansas. According to Steiert and Meinzer (1995), at least 2000 playa basins are found in southwestern Kansas, but more probably exist.

Revised map of Kansas physiographic regions.
Taken from Aber and Aber (2009).

State Geologist Erasmus Haworth refered to these depressions as sinkholes, or swales, or lagoons, sometimes filled with water ... It has now been five years or more since any of them have held water for any continuous time. During July and August of 1895 they were nearly filled from the north side of the state to the south. But the water soon sank away, or was evaporated, so that they were entirely dry for perhaps eleven months out of the year (Haworth 1897, p. 19-20).

The area between Scott City and Garden City includes several enclosed drainages, such as White Woman Basin and the basin of Dry Lake (see above), which may contain streams and lakes during wet years. Other major enclosed drainage basins include Cheyenne Bottoms and Quivira National Wildlife Refuge in the central portion of the state.

Wind resource planner.

At this site, click on the option for percentage playas. Zoom in and click on playa lakes. Scott, Lane and Finney counties in west-central Kansas have a great abundance of playas. This is a key area for us to investigate. Below are a couple topographic maps created from a high-resolution elevation dataset for the United States.

Regional topography between the Smoky Hill River and Arkansas River valleys. Notice the wedge-shaped depression between Scott City and Garden City Elevations given in meters; UTM projection (zone 14). Image processed by J.S. Aber.
Detailed map of playas and related features in the study area. 1 - playa west of Scott City, 2 - White Woman Basin, 3 - Shallow Water, 4 - Sondreagger Lake, 5 - Corrigan Lake, 6 - Ackley and McCoy lakes, 7 - Pawnee Mound, 8 - Dry Lake, 9 - unnamed basin east of Dry Lake. Elevations given in meters; UTM projection (zone 14). Image processed by J.S. Aber.

Many opinions have been advanced concerning the origin of playa depressions, ranging from subsurface solution to wind erosion or buffalo wallows. Haworth (1897) preferred underground solution as the explanation. This may well be the case for some playas in central Kansas, where underground salt beds exist, but is probably not a viable explanation for the High Plains region, which is underlain by the Ogallala Formation (sand and gravel). On the other hand, most playa basins are much too large to explain as buffalo wallows. So the impact of wind erosion and deposition may be considered a leading cause for playas in many cases.

Topographic map of Dry Lake vicinity in Scott, Finney and Lane counties. Dry Lake basin is separated from another playa basin to the east by a tract of sand hills where the three counties meet. Elevations given in meters; contour interval = 5 m (~16 feet). Adapted from Scott City, Kansas 1:100,000 metric topographic map, U.S. Geological Survey (1985).
Topographic map of Sondreagger Lake and Corrigan Lake vicinity in Finney County. Sondreagger Lake is situated in an ideally shaped playa basin, approximately 4 miles (6½ km) long by 1 mile (1.6 km) wide. Elevations given in meters; contour interval = 5 m (~16 feet). Adapted from Scott City, Kansas 1:100,000 metric topographic map, U.S. Geological Survey (1985).

In the late 19th century, widespread ground water beneath the High Plains was indicated by numerous springs draining along the sides of valleys incised into the plains and along the eastern margin of the plains (Haworth 1897). Playa basins were an important source of recharge for the aquifer (Steiert and Meinzer 1995). However, the aquifer has been exploited increasingly since the 1950s, as manifested by the rapid spread of center-pivot irrigation. In many portions, the rate of ground-water extraction exceeds the rate of recharge from natural sources of infiltration, which amounts to ground-water mining. In other regions, particularly sand hills areas, recharge may be adequate to maintain ground-water reserves. Nonetheless, the overall result has been decline of surface water in playas, springs, and streams throughout the region.

Geomorphic questions

The fundamental geomorphic problem is to explain how enclosed drainage basins come into existence under the conditions that exist in central and western Kansas at present and in the recent geological past, in other words the geomorphic processes that operated during the Holocene and Pleistocene. Based on playa circumstances, several related questions may be considered.

  1. What current and past processes operated in playa basins?
  2. Were basins created primarily by erosion or deposition?
  3. What climatic influences may operate, now and in the past?
  4. What are connections between surface and subsurface processes?
  5. How have human activities modified playa geomorphology?

During the class field trip, we plan to visit the following specific locations. As time and weather allow, we also will tour or briefly visit other playa sites on the way and in between these main sites.

Topography of Cheyenne Bottoms and the Great Bend of the Arkansas River in central Kansas. The bottoms is surrounded by a rim of Cretaceous bedrock on the northern, western, and southern sides. However the eastern margin is comprised of alluvial and aeolian sediments. Elevations given in meters; UTM projection (zone 14). Image processed by J.S. Aber.
Topography of the Quivira National Wildlife Refuge vicinity including Little and Big Salt Marsh. Rattlesnake Creek, a saline stream, flows into Little Salt Marsh from the west, and a series of canals transports water from there into Big Salt Marsh. Elevations given in meters; UTM projection (zone 14). Image processed by J.S. Aber.

From the several playas we visit, each student will select one site for further research. Students should investigate the general geomorphic conditions and geologic setting for the chosen site along with drainage, climate, vegetation, and human land use. In addition to SFAP taken during field trips, each student should gather representative ground photos, various maps, satellite images, hydrologic data, and other means to illustrate his/her site.

Prepare a webpage report on the selected playa. The report should describe general characteristics of the playa with an emphasis on topographic expression and typical landforms. Utilize SFAP to illustrate these conditions along with other types of maps and imagery. The report should be referenced fully in standard scientific style, in a manner similar to this webpage--see instructions for preparing student webpages.

Note: Webpage reports--first drafts--are due by Nov. 20th.
Final versions are due by Dec. 11th.

References

Return to field geomorphology syllabus.
ES 546 © J.S. Aber (2009).