can require specialized methods of collection (e.g., dissolved gases require
gas-tight sampling methods; unstable analytes may require pre-preservation with
acids or chemicals).
Although there have been many advances in cave instrumentation over the past
several decades, there are few detailed descriptions of the instrumentation and data
collection, processing, and management, leaving each new researcher to “reinvent
the wheel.” The objective of this chapter is to describe instrumentation for continuous measurement of hydrologic and geochemical parameters of cave dripwater,
other hydrologic inputs such as precipitation and soil water, and outfalls such as a
cave stream or spring. The instrumentation described herein was designed and
deployed in James Cave, located in the doline-dominated karst systems of the
Appalachian Great Valley in southwestern Virginia (USA). The overall goal of
the James Cave research program is to evaluate the quantity and quality of recharge
in karst systems. More details about the James Cave program are included in
graduate theses by S. Eagle [21] and J. Gerst [22].
2 Study Site
The case study site, James Cave, is located in Pulaski County, Virginia (USA)
(Fig. 1). James Cave is an ideal study site for three primary reasons: it is representative of caves in the Appalachian Great Valley; it is a short drive from the Virginia
Tech campus; and it is accessible for installation and maintenance of instruments.
These are important factors in selection of a site where frequent visits and equipment maintenance may be required. The study area is in a temperate climate zone,
with an average annual temperature of 11.3
C and an average annual precipitation
of 92.4 cm (period of record: 1969–2009) [23].
James Cave is developed in limestones and dolostones of the CambroOrdovician Conococheague Formation (Fig. 2) in the Valley and Ridge physiographic province. Bedrock fracturing/jointing developed primarily as a result of the
Pulaski fault system, a complex series of ENE-trending low-angle thrust faults [24,
25]. Soils overlying the cave are composed of Lowell silt loam and the Wurno–
Newbern–Faywood silt loam [26], derived from residuum from weathered limestone and shale. Soils range in thickness from 0.25 to 2 m and rest directly on
relatively unweathered bedrock with little saprolite development.
James Cave consists of approximately 2.3 km of cave passage, with a smaller
section instrumented for this project (Fig. 3). There are two entrances to the cave,
both located within sinkholes (Fig. 4). The source of the stream within James Cave
is not well known. Based on the lateral extent of limestone around the field site and
the lack of perennial sinking surface streams on the sinkhole plain, it appears that
the cave stream is derived entirely from autogenic sources (i.e., dripwaters). During
large storm events, it has been observed that overland flow enters the two entrances
as well as other sinkholes within the likely watershed of the cave stream.
208
M.E. Schreiber et al.
gas-tight sampling methods; unstable analytes may require pre-preservation with
acids or chemicals).
Although there have been many advances in cave instrumentation over the past
several decades, there are few detailed descriptions of the instrumentation and data
collection, processing, and management, leaving each new researcher to “reinvent
the wheel.” The objective of this chapter is to describe instrumentation for continuous measurement of hydrologic and geochemical parameters of cave dripwater,
other hydrologic inputs such as precipitation and soil water, and outfalls such as a
cave stream or spring. The instrumentation described herein was designed and
deployed in James Cave, located in the doline-dominated karst systems of the
Appalachian Great Valley in southwestern Virginia (USA). The overall goal of
the James Cave research program is to evaluate the quantity and quality of recharge
in karst systems. More details about the James Cave program are included in
graduate theses by S. Eagle [21] and J. Gerst [22].
2 Study Site
The case study site, James Cave, is located in Pulaski County, Virginia (USA)
(Fig. 1). James Cave is an ideal study site for three primary reasons: it is representative of caves in the Appalachian Great Valley; it is a short drive from the Virginia
Tech campus; and it is accessible for installation and maintenance of instruments.
These are important factors in selection of a site where frequent visits and equipment maintenance may be required. The study area is in a temperate climate zone,
with an average annual temperature of 11.3
C and an average annual precipitation
of 92.4 cm (period of record: 1969–2009) [23].
James Cave is developed in limestones and dolostones of the CambroOrdovician Conococheague Formation (Fig. 2) in the Valley and Ridge physiographic province. Bedrock fracturing/jointing developed primarily as a result of the
Pulaski fault system, a complex series of ENE-trending low-angle thrust faults [24,
25]. Soils overlying the cave are composed of Lowell silt loam and the Wurno–
Newbern–Faywood silt loam [26], derived from residuum from weathered limestone and shale. Soils range in thickness from 0.25 to 2 m and rest directly on
relatively unweathered bedrock with little saprolite development.
James Cave consists of approximately 2.3 km of cave passage, with a smaller
section instrumented for this project (Fig. 3). There are two entrances to the cave,
both located within sinkholes (Fig. 4). The source of the stream within James Cave
is not well known. Based on the lateral extent of limestone around the field site and
the lack of perennial sinking surface streams on the sinkhole plain, it appears that
the cave stream is derived entirely from autogenic sources (i.e., dripwaters). During
large storm events, it has been observed that overland flow enters the two entrances
as well as other sinkholes within the likely watershed of the cave stream.
208
M.E. Schreiber et al.