After registering for the Symposium, we will contact you directly about choosing a field trip.

Field Trip Option 1 – The Geology Field Trip Is Full

Geology of the Buffalo National River by Canoe: Tyler Bend to Gilbert

Download the Geology Float Guide here.

The trip begins with a two-hour vehicle ride from Eureka Springs to Tyler Bend Campground on the Buffalo River. We will stop in Harrison, Arkansas to pick up our lunches.

At Tyler Bend, we will have a short stop at the Visitor Center, a safety talk, and discussion of the significance of Buffalo National River. The trip to Gilbert is 5.4 miles in length with a gentle 3 foot per mile gradient. There are several stops along the way to view the geology and karst features. The geology includes Ordovician, Silurian, and Mississippian units, primarily limestone, though a limited amount of sandstone and shale is present. The gravel bars along the way are comprised of Mississippian chert and Pennsylvanian sandstone eroded from the overlying formations. The float is expected to take 3 to 4 hours.

We will take out at Gilbert, population 33. The town of Gilbert is served by septic systems. Gilbert Spring which was formerly the town’s drinking water source and provided water for the steam locomotives on the M&NA line has received pollutants from some of these septic systems. In 2002 Ozark Underground Lab, with assistance from NPS conducted dye traces from 24 of these septic systems. Two were found to contribute large amounts of dye to the spring. Grant funding was made available to repair these faulty systems. This improved the water quality of the spring for over a decade. In the past few years the spring has begun showing bacterial pollution again. It is time to take a fresh look at the systems and look for solutions to fix this problem. After a visit to the Gilbert General Store, we will load up and head back to Eureka Springs.

Field Trip Option 2 The OUL Field Trip Is Full

Field Trip to the Ozark Underground Laboratory, Protem, MO

The Ozark Underground Laboratory conducts water and land use investigations with special emphasis on karst and fractured rock landscapes. The Ozark Underground Laboratory consists of 2,900 acres of Ozark hill land overlying the 10,000 feet of known passage in Tumbling Creek Cave. The cave is a designated National Natural Landmark primarily because the fauna is the most diverse known for any U.S. cave west of the Mississippi River. The purposes of the Ozark Underground Laboratory are to encourage education, prudent resource use, and research in the cave regions of the United States. To do this, the Laboratory conducts educational field trips, is available for extended field studies, provides research facilities and assistance, and does consulting work and contract investigations on water and land use problems in cave regions. The term “laboratory” may create an image of a sterile room with test tubes and people in white lab coats. That is not at all what the Ozark Underground Laboratory is about. A laboratory is a place where scientists and technicians do their work. Our work deals with the land, and our laboratory is a piece of the land which includes caves, springs, sinkholes, and other features. Our goal is to improve the way people live with, and relate to, the natural resources of cave regions. Better public understanding of how the surface and subsurface interact is crucial to such improvements; this is the primary purpose of the educational field programs at the Laboratory. At Tumbling Creek Cave our management is simple; it is based on the conviction that any action, which tends to maintain physical and biological integrity, stability, diversity and beauty is proper. Proper management must, to the extent of our knowledge and ability, take proper actions.

Field trips to the Laboratory consist of two segments: a surface tour and an underground tour.

The two-mile long surface tour is usually conducted first. Relationships between the surface and the cave are stressed since the surface and the subsurface in cave regions are integrally tied together; differences or changes in the surface are reflected in the cave. For example, differences between the temperature and moisture conditions on north and south slopes are reflected in the surface vegetation as well as in the underlying cave system. The surface at the Ozark Underground Laboratory includes typical north and south slope forest plant communities of oak and hickory. There are also some post oak flats (where most of the trees are post oaks, and are stunted due to shallow fragipan layers in the soil). There are some excellent “glades”, characterized by eastern red cedar, a few hardwoods, and 100 acres of restored native grasses including big and little bluestem and Indian grass plus forbs. An important way of relating surface conditions to the underlying cave is to consider how water enters the cave system. There are two types of groundwater recharge: discrete recharge and diffuse recharge. Discrete recharge occurs in very localized areas where substantial quantities of water enter the groundwater system. In contrast, diffuse recharge is small quantities of water entering the groundwater system from almost every point on the landscape. A number of sinkholes and losing stream segments are visited on the surface tour. One sinkhole along the surface tour can channel at least 50 gallons of water per minute from the surface into the cave system. A losing stream segment in Bear Cave Hollow (the surface valley) has transported up to 500 gallons of water per minute from the surface into the cave. The surface tour passes a pond where we consider similarities and differences between the energy levels of ponds and caves. One major difference is the lack of sunlight to furnish energy to the cave system. The primary source of energy for our cave system is bat guano from a summer colony of about 40,000 Grey Bats (Myotis grisescens). These bats eat about 300 pounds of bugs a night; this yields several hundred pounds of guano to the cave system each day the bats use the cave. One study at the Laboratory found guano to contain about 3.5 Calories per gram; this is approximately the caloric value of hamburger. People living in cave regions often lack a workable understanding of how underground conditions affect surface activities and vice versa. For example, if you think that sinkholes and hydrologically similar features are adequate sites for waste disposal because you view the subsurface as an infinite filter, you or a neighbor may end up drinking sewage or trash from your spring or well. If, on the other hand, you more accurately understand the relationship of the surface and the subsurface, you can avoid many waste disposal blunders. The surface tour endeavors to demonstrate the common characteristics of cave regions uncommonly well, and to identify the unique characteristics of the landscape.

The trail through Tumbling Creek Cave is 2,100 feet long. The purpose of the trail is to keep travel in the cave on a narrow, restricted route so that areas off the trail are kept in near-natural condition. There is no permanent lighting in the cave. The cave has approximately two miles of mapped passages; field trips visit about 20% of the known cave. Travel into the remaining 80% of the cave is stringently restricted to protect the cave and cave fauna. Passages in the cave display great diversity. Some chambers are huge; the Big Room is sixty feet high, 120 feet long, and 100 feet wide. Other passages are narrow and winding. In one place a 20- foot high waterfall cascades from the side of a chamber. Several hundred feet of the trail is adjacent to Tumbling Creek, the underground stream. The cave stream drains an area of nine square miles as delineate d by over 60 groundwater traces. The flow of the stream ranges from 0.1 cubic feet per second (cfs) to 100 cfs; flow is typically between 0.5 to 2.0 cfs. Low flows occur in late summer and early fall; high flows occur within a few hours of major surface storms. Secondary mineral deposits, particularly calcite, aragonite, hausmannite, and moon milk are found in much of the cave. Stalactites, stalagmites, draperies, columns, soda straws, rimstone dams, and other dripstone deposits of calcite and/or aragonite are abundant. Hausmannite is a manganese oxide mineral found coating rocks in the cave stream, on waterfalls, and at other points where surface waters rapidly enter the cave. In some portions of the cave stalactites, stalagmites, and other cave formations are no longer depositing, but instead are being dissolved. Factors causing changes from deposition to solution are considered on field trips. These changes are commonly associated with surface events. This demonstrates that the cave is not a separate world, but instead is integrally tied to the surface and to conditions occurring on the surface. Our cave fauna is very large and diverse. There are at least 116 species known from the cave, and more will undoubtedly be discovered as more detailed work is conducted. Many are true cave dwellers (troglobites). The cave provides habitat for four federally threatened or endangered species. These are the Endangered Gray Bat (Myotis grisescens), Endangered Indiana bat (Myotis sodalis); Threatened Northern Long-Eared Bat (Myotis septentrionalis); and the Endangered Tumbling Creek Cavesnail (Antrobia culveri). Despite extensive searches, the Tumbling Creek Cavesnail is limited to this cave and its associated downgradient groundwater system. Substantial efforts have been underway since 1999 to improve conditions for the Cavesnail. These have included major trapping and removing of the invasive Ringed Crayfish. These efforts are a major focus of field trips. On trips through the cave, time is spent observing and discussing the cave fauna. Some animals have very limited habitats within the cave; we typically discuss the impact of man’s use of caves and the overlying land on cave fauna.

Each person visiting the Ozark Underground Laboratory should bring field clothes, comfortable boots or shoes with tread, a flashlight with new batteries, insect repellent from April through October, a raincoat, and food. In order to minimize the spread of White Nose Syndrome, Tyvek suits (or coveralls and Tyvek booties) will be provided for the in-cave portion of the field trip.  Wet wipes (Isopropyl Alcohol and/or Clorox ) will be provided to wipe down flashlights and cameras.

Field Trip Option 3

Walking Tour of Karst Features in Eureka Springs

By Jim Helwig, Field Trip Leader (479-981-9669)

The field trip will cover the topography, geology and hydrology of karst and springs of the City of Eureka Springs. Environmental management issues to be covered are water quality monitoring, stormwater, slope stability, and the general history of development of public water and wastewater infrastructure in the “City that Springs built.”

NOTE: Most of the walking is on sidewalks with little climbing, but wear sturdy footgear. Total distance including return to start point is 2.6 miles. A Field Trip Guidebook will be distributed.

ITINERARY, Wednesday October 18, 2017. (May be subject to minor changes.)

STOP 1. 8:30 AM sharp: Meet at the fountain in Basin Spring Park, next to the hotel. Introduce Ozarks geology and karst systems, and the guidebook. Observe Basin Spring and the stratigraphy of the Ordovician, Devonian and Mississippian strata. Depart at 8:50 AM and walk 0.2 miles to next stop.

STOP 2. 9:00 AM. Sweet Spring. Discuss history and management of the springs reservations. Present the results of dye tracing and smoke testing to establish recharge pathways and contamination by sewage pipes. Depart at 9:20 AM and walk 0.1 miles to next stop.

STOP 3. 9:25 AM. Harding Spring. Examine fractured Mississippian limestone and the spring. What are the factors that control movement of ground water? Further discuss water quality and hydrology in karst, storm events, contamination of the springs, and protective activities of the City and Eureka Springs Springs Committee. Show water quality monitoring results. Depart at 9:45 AM and walk 0.2 miles to next stop.

STOP 4. 9:55 AM. Crescent Spring. A brief stop and photo opportunity. Discuss Eureka trails system. Depart at 10:05 AM and walk 0.5 miles to next stop. (May be a few show and tell spots along the way.)

STOP 5. 10:35 AM. Grotto Spring. Look at cave, karst features, and landslide. Discuss karst and slope stability management practices. Depart at 11 AM and walk 0.2 miles to Harmon Park.

STOP 6. 11:10 AM. Harmon Recreational Park and Eureka Springs Parks Department office. (Bathroom is available.) Examine dissolution features in St. Joe limestone, see Devonian sandstone and Dairy Spring box.

STOP 7. 11:15 AM. Cardinal Spring and Fuller Hollow. View check dams, rain garden. Discuss cave fauna, stormwater and geohazards. Wrap up discussion on water and karst in Eureka Springs.

11:40 AM. End of Field Trip. The walk back to Basin Park by the same route is about 1.2 miles and should take you about a half hour. An alternate hiking route via the Harmon Loop trail and Crescent Hotel involves some steep walking but takes about the same amount of time.