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Sinkholes and a Disappearing Lake: Victory Lake Case Study
Abstract
Human-induced sinkhole collapse can result in drastic changes to landscape aesthetics and present challenges to land managers seeking to determine the plausibility of restoration, the amount of financial investment needed, and the long-term sustainability of tampering with karstic environments. Alteration of groundwater flow in a karstic environment expedited the formation of large sinkholes in the southern end of man-made Victory Lake, causing it to drain immediately. Soon after the lake emptied in 1986, two unsuccessful attempts were made to restore the 13 ha (32 ac) lake. The sinkholes formed in the southern basin were completely in-filled, eliminating 3 ha (8 ac) of lake basin and significantly altering the original lake morphology. Some twenty-seven years later, Victory Lake is holding some water in the shallow basin at the northern end and would primarily be classified as a marshy wetland. This study was initiated to investigate the current relationship between the groundwater and surface water at the lake’s altered basin to determine the potential for it to be restored fully or partially as a recreational focal point of the Berry College campus. Over the course of one year we measured the inputs (stream flow and precipitation) and outputs (evaporation and surface water outflow) of the lake system. We were able to conclude that groundwater is not likely contributing to the lake, based on inorganic and stable isotope (18O and 2H) water chemistry analysis and the deep position of the groundwater table relative to the lake bottom. From the results of dye-tracer tests conducted in the lake, we concluded that basin water may not be escaping downward at measurable rates because of its clay bottom. Our overall water-budget analysis confirms an adequate water volume entering by rainfall and ephemeral stream inflow; nearly 90% of the water leaves Victory Lake through surface-water outflow. Water loss through evapotranspiration during spring and summer months overcomes the gain accomplished during wetter and cooler months, particularly February. Through an investigation of water level records kept for campus monitoring wells from 1998 through 2012 we confirm that the groundwater table has stabilized and the immediate threat of new sinkhole formation is minimal. Restoration of Victory Lake to its original picturesque meeting spot may be possible through creative engineering strategies and project financing. However, we question the longevity of managing a karstic environment and consider the potential risks to infrastructure, groundwater, and human health should lake bottom failure occur again on campus. © 2014, National Speleological Society Inc. All right reserved.
... There are also numerous documented examples of anthropogenic impacts triggering rapid development of cover-collapse sinkholes. A notable example is that presented by the draining of Victory Lake in Georgia (Jovanelly, 2014). This man-made recreational lake was entirely drained by the lowering of the groundwater table by limestone quarrying: as a result cover-collapse sinkholes formed beneath the lake bed and linked the water in the lake to an existing subsurface karst aquifer, which itself was connected to the quarry, causing the lake to drain overnight (Jovanelly, 2014). ...
... A notable example is that presented by the draining of Victory Lake in Georgia (Jovanelly, 2014). This man-made recreational lake was entirely drained by the lowering of the groundwater table by limestone quarrying: as a result cover-collapse sinkholes formed beneath the lake bed and linked the water in the lake to an existing subsurface karst aquifer, which itself was connected to the quarry, causing the lake to drain overnight (Jovanelly, 2014). Similar aquifer drawdown impacts resulting from quarry and mine operations and aquifer over-exploitation have been described in Italy (Parise and Pascali, 2003;Dell'Aringa et al., 2014), China (Jia et al., 2018;Pan et al., 2018), Iran (Heidari et al., 2011;Khanlari et al., 2012) and Belgium (Kaufmann and Quinif, 2002), amongst numerous other examples of this phenomenon in the USA and elsewhere, as reviewed by Langer (2001, p. 15-30). ...
... The cover-collapse sinkholes documented during this study are similar to sinkholes developed in other karst areas buried by thick Quaternary overburden deposits that have been impacted as a result of regional water table lowering. As mentioned in the Introduction, there are numerous examples of quarrying or withdrawal of water from aquifers lowering water tables and causing sinkholes to form in surrounding land, due to the removal of buoyant support for sediments or soils above the sediment/limestone contact (Kaufmann and Quinif, 2002;Parise and Pascali, 2003;Heidari et al., 2011;Khanlari et al., 2012;Jovanelly, 2014;Dell'Aringa et al., 2014;Jia et al., 2018;Pan et al., 2018). The process is well-illustrated in the review by Langer (2001, fig. ...
Recent catastrophic sinkhole collapse caused by regional water table lowering induced by quarrying has led to the partial exhumation and reactivation of a buried karst cave system in the floor of the Railton Valley in the lowlands of northern Tasmania, Australia, and widespread sinkhole development. Extensive silty sediments exposed in sinkholes, OSL dated to approximately 237 ka, are interpreted to be lacustrine deposits derived from rapidly deposited glacial outwash. The silty sediments have mineralogy consistent with derivation from a source in the upper Mersey catchment rather than locally and are interpreted to be the product of rapid melting of the Mersey Valley glacier during the MIS 8/7e transition. Thick Last Glacial alluvial fan and Holocene flood-plain deposits mantle the lacustrine sediments. Exposures of glacial erratics and weathered till in streambeds provide further evidence that the valley was impacted by earlier Pleistocene glaciations.
... There are also numerous documented examples of anthropogenic impacts triggering rapid development of cover-collapse sinkholes. A notable example is that presented by the draining of Victory Lake in Georgia (Jovanelly, 2014). This man-made recreational lake was entirely drained by the lowering of the groundwater table by limestone quarrying: as a result cover-collapse sinkholes formed beneath the lake bed and linked the water in the lake to an existing subsurface karst aquifer, which itself was connected to the quarry, causing the lake to drain overnight (Jovanelly, 2014). ...
... A notable example is that presented by the draining of Victory Lake in Georgia (Jovanelly, 2014). This man-made recreational lake was entirely drained by the lowering of the groundwater table by limestone quarrying: as a result cover-collapse sinkholes formed beneath the lake bed and linked the water in the lake to an existing subsurface karst aquifer, which itself was connected to the quarry, causing the lake to drain overnight (Jovanelly, 2014). Similar aquifer drawdown impacts resulting from quarry and mine operations and aquifer over-exploitation have been described in Italy (Parise and Pascali, 2003;Dell'Aringa et al., 2014), China (Jia et al., 2018;Pan et al., 2018), Iran (Heidari et al., 2011;Khanlari et al., 2012) and Belgium (Kaufmann and Quinif, 2002), amongst numerous other examples of this phenomenon in the USA and elsewhere, as reviewed by Langer (2001, p. 15-30). ...
... The cover-collapse sinkholes documented during this study are similar to sinkholes developed in other karst areas buried by thick Quaternary overburden deposits that have been impacted as a result of regional water table lowering. As mentioned in the Introduction, there are numerous examples of quarrying or withdrawal of water from aquifers lowering water tables and causing sinkholes to form in surrounding land, due to the removal of buoyant support for sediments or soils above the sediment/limestone contact (Kaufmann and Quinif, 2002;Parise and Pascali, 2003;Heidari et al., 2011;Khanlari et al., 2012;Jovanelly, 2014;Dell'Aringa et al., 2014;Jia et al., 2018;Pan et al., 2018). The process is well-illustrated in the review by Langer (2001, fig. ...
A reactivated cave system induces rapidly developing cover-collapse sinkholes in Tasmania, Australia. Abstract The reasons of rapid development of cover-collapse sinkholes near Railton, Tasmania were investigated after sinkholes first appeared in a mature pine plantation in 2011. Sinkhole monitoring, dye tracing, chemical analyses of stream water and field observations indicated that large sinkholes in Quaternary alluvium overlying Ordovician limestone resulted from deepening of a limestone quarry south of the plantation. Intersection of a cave system during quarrying lowered the local water table, initiated streamsinks, and caused streams that previously flowed north towards the Mersey River to flow south to the quarry, via streamsinks and reactivated subsurface channels. Concurrently, the thickness of the vadose zone in thick Quaternary sediments overlying the limestone increased, hydraulic support for the sediments decreased, and numerous cover-collapse sinkholes formed. Chemical data including isotope analyses confirmed that the local aquifer is mainly recharged after high winter rainfall during high stream flow, when a proportion of the water in surface streams also flows directly northwards to the Mersey River. During low (summer) flow most water in surface streams flows into streamsinks and south into the quarry via the cave system. It is then pumped to a surface stream running north through the area in question, returns into the cave system via streamsinks and sinkholes, and finally returns to the quarry. The study demonstrates that water-table lowering by quarrying in limestone is not confined to cones of depression but may extend for kilometres if relict subsurface stream channels are intersected. In this area, the rapid development of cover-collapse sinkholes presents risks to infrastructure (a railway line, an electricity transmission line, and roads); to stream biodiversity because of altered water flow duration and water quality; to the safety of forest contractors, particularly those using heavy machines; and to the future use of presently productive land for economic return.
... On 4 November, we discovered that the Bobcat was no longer present, and we assumed it escaped. The impact of sinkholes on the landscape and human population has been well documented, e.g., causing damage to roads and buildings (Dougherty andPerlow 1988, Hermosilla 2012), draining streams and lakes (Jovanelly 2014), conducting contaminants into aquafers (Lindsey et al. 2010), and causing loss of human life (Hermosilla 2012). The creation of microhabitats in the form of pools and mesic depressions has also been studied (Francl et al. 2010, Keiller 2011. ...
Sinkholes are common in karst terrain, and their impacts on wildlife are not well documented. At the Joseph W. Jones Ecological Research Center in southwestern Georgia, we observed 3 separate incidents of wildlife being negatively impacted by entrapment within a single sinkhole.
The leading role of dissolution and the dominant subsurface drainage determine the special idiosyncrasy of karst geomorphology, with some notable variations depending on the type of soluble rock. The formation of karren is essentially related to the uneven or differential dissolution of the bedrock surface controlled by a number of factors, resulting in the development of depressions, clefts, channels, tubes, protruding features, and irregular patterns. Sinkholes or dolines are enclosed depressions with internal drainage widely regarded as one of the most characteristic landforms of karst landscapes. They are typically circular to subcircular in plan and show wide morphological diversity (cylindrical‐, conical‐, bowl‐, and pan‐shaped). In some cases, the variable geometry of the sinkholes can indicate different evolutionary stages and the relative age of the depressions. In nature, a complete spectrum between suffosion, collapse, and sagging sinkholes can be found in covered karst settings.
Karst is inherently dynamic, and this may be manifest in unexpected ways, which may have major implications for management of protected areas, where changes may have major impacts on visitor numbers and revenue streams. In Five Blues Lake National Park, Belize, the principal visitor focus is Five Blues Lake itself. An anomalous feature with characteristics of a karst window or cenote but in the setting of a polje or ponor lake, Five Blues has both surface and underground drainage components. Establishment of the national park proceeded under the impression that the lake was a permanent feature, but over July 20 to 25, 2006, the lake drained rapidly underground. Without the lake, visitor numbers and park revenues declined, and the park was all but abandoned. The lake refilled in 2007, but visitor numbers continue to lag. Management and promotion of hydrologic features within protected areas needs to take such possibilities into account, emphasizing variability and change and avoiding a focus on conditions that may not prevail at any given time.
Groundwater inflow and outflow contributions to the hydrologic budget of lakes can be determined using a stable isotope (18O/16O) mass balance method. The stable isotope method provides a way of integrating the spatial and temporal complexities of the flow field around a lake, thereby offering an appealing alternative to the traditional time and labor intensive methods using seepage meters and an extensive piezometer network. In this paper the method is applied to a lake in northern Wisconsin, demonstrating that it can be successfully applied to lakes in the upper midwest where thousands of similar lakes exist. Inflow and outflow rates calculated for the Wisconsin lake using the isotope mass balance method are 29 and 54 cm/yr, respectively, which compare well to estimates, derived independently using a three-dimensional groundwater flow and solute transport model, of 20 and 50 cm/yr. Such a favorable comparison lends confidence to the use of the stable isotope method to estimate groundwater exchange with lakes. In addition, utilization of stable isotopes in studies of groundwater-lake systems lends insight into mixing processes occurring in the unsaturated zone and in the aquifer surrounding the lake and verifies assumed flow paths based on head measurements in piezometers.
Heavily karstified gypsum and dolomite aquifers occur in the Permian (Zechstein Group) of Eastern England. Here rapid active gypsum dissolution causes subsidence and abundant sinkholes affect an approximately 140-km by 3-km area from Darlington, through Ripon to Doncaster. The topography and easterly dip of the strata feed artesian water through the dolomite up into the overlying gypsum sequences. The shallow-circulating groundwater emerges as sulfate-rich springs with temperatures between 9-12 oC, many emanating from sinkholes that steam and do not freeze in the winter (such as Hell Kettles, Darlington). Water also circulates from the east through the overlying Triassic sandstone aquifer. Calcareous tufa deposits and tufa-cemented gravels also attest to the passage and escape of this groundwater.
The sizes of the sinkholes, their depth and that of the associated breccia pipes is controlled by the thickness of gypsum that can dissolve and by the bulking factors associated with the collapsed rocks. The presence of sulfate-rich water affects the local potability of the supply. Groundwater abstraction locally aggravates the subsidence problems, both by active dissolution and drawdown. Furthermore, the gypsum and dolomite karstification has local implications for the installation of ground-source heat pumps. The sulfate-rich springs show where active subsidence is expected; their presence along with records of subsidence can inform planning and development of areas requiring mitigation measures.
Ksiromero occupies an area of 107 km2 in the northeast section of the Prefecture of Aitoloakarnania in western Greece. Its karst is developed primarily on beds of 10–200 m thick Triassic carbonate breccia conglomerates which underlie 70 % of the region. Other karstified units overly 200–300 m thick sequences of upper Triassic to early Jurassic limestones and dolomites and an underlying 150 m thick Triassic gypsum deposit. Major karst features include sinkholes and poljes that capture all surface water. Open caves and conduits are rare due to in-fill by residual terra rossa soils. “Ksiromero” is Greek for “dry place.” While in one of the wetter regions of Greece, with a mean annual precipitation of 962–1,040 mm and a mean evapotranspiration rate of 47 %, no perennial springs are known, surface water is rare, and accessible groundwater is minimal. Some shallow wells in the breccia conglomerate serve as small, local water supplies. Geochemical analyses of water samples from two wells show significant differences due to aquifer type (limestone versus terra rossa) but groundwater is suitable at least for irrigation and livestock and probably human consumption. Generally, domestically used water is supplied to Ksiromero from a neighboring region. Water for agriculture is stored in more than 75 reservoirs, some of which are natural sinkholes but most are excavated in terra rossa soils of poljes and large sinkholes. Shallow groundwater occurs in some of these reservoirs, as well as seasonally captured storm water, but much is pumped in from the adjacent region or from nearby wells. This system is adequate for the area’s modest water needs, but not for potential increased demand. Most land use is farming and pasture, and limited to the relatively flat floors of sinkholes and poljes. The absence of sanitary landfills and other agricultural contaminants potentially threaten groundwater quality, but the impacts are not presently quantifiable due to insufficient aquifer characterization.
More than a thousand sinkholes have developed along the western coast of the Dead Sea since the early 1980s, more than 75% of them since 1997, all occurring within a nar-row strip 60 km long and <1 km wide. This highly dynamic sinkhole development has accelerated in recent years to a rate of ~150– 200 sinkholes per year. The sinkholes cluster mostly over specifi c sites up to 1000 m long and 200 m wide, which spread parallel to the general direction of the fault system associ-ated with the Dead Sea Transform. Research employing borehole and geophysical tools reveals that the sinkhole formation results from the dissolution of an ~10,000-yr-old salt layer buried at a depth of 20–70 m below the surface. The salt dissolution by groundwater is evidenced by direct observations in test boreholes; these observations include large cavities within the salt layer and groundwater within the confi ned subaquifer beneath the salt layer that is undersaturated with respect to halite. Moreover, the groundwater brine within the salt layer exhibits geochemical evidence for actual salt dissolution (Na/Cl = 0.5–0.6 compared to Na/Cl = 0.25 in the Dead Sea brine). The groundwater heads below the salt layer have the potential for upward cross-layer fl ow, and the water is actually invading the salt layer, apparently along cracks and active faults. The abrupt appear-ance of the sinkholes, and their accelerated expansion thereafter, refl ects a change in the groundwater regime around the shrinking lake and the extreme solubility of halite in water. The eastward retreat of the shoreline and the declining sea level cause an eastward migration of the fresh–saline water interface. As a result the salt layer, which originally was saturated with Dead Sea water over its entire spread, is gradually being invaded by fresh groundwater at its western boundary, which mixes and displaces the original Dead Sea brine. Accordingly, the location of the west-ern boundary of the salt layer, which dates back to the shrinkage of the former Lake Lisan and its transition to the current Dead Sea, constrains the sinkhole distribution to a narrow strip along the Dead Sea coast. The entire phenomenon can be described as a hydrological chain reaction; it starts by intensive extraction of fresh water upstream of the Dead Sea, continues with the eastward retreat of the lake shoreline, which in turn modifi es the groundwater regime, fi nally triggering the formation of sinkholes.
Sinkholes characterize karst topography the world over. A mainly natural phenomenon, their development in carbonate rocks, such as limestones of Florida and the Yucatan Peninsula, is well known. However, the fat that sinkholes also form in or above highly soluble evaporite rocks, such as gypsum and salt, is far from common knowledge. And sinks formed in these evaporite rocks can be at least as dramatic and troublesome as those in carbonate rocks. Evaporite deposits form when various salts precipitate from evaporating water, mainly seawater. The principal evaporite rocks include gypsum (or anhydrite, its anhydrous form) and salt (halite), although potash (sylvite) and other rarer salts also are locally important. Evaporites have the highest solubility of the common rocks; water that is unsaturated with respect to gypsum (CaSO4•2H2O) or salt (NaCl) rapidly dissolves them and carries them off in solution. Indeed, gypsum and salt are, respectively, 150 and 7,500 times more soluble than limestone. Evaporite rocks underlie about 35–40% of the United States and are found in 32 of the 48 contiguous states. They are also found in Canada and Mexico, and are widespread on other continents.
Data from the last 20 yr for sinkhole occurrences in west-central Florida are used in conjunction with population and housing data, including house prices, to assess the risk of a house being affected by a sinkhole, together with the likely economic loss. The top five relocation cities in each of Hillsborough, Pasco, and Pinellas counties are investigated in detail to determine the relative risk as well as the absolute risk. Because of the massive urbanization occurring in these areas, which are characterized by karst topography, the sinkhole risk is increasing because of the excessive demand for water and the subsequent overpumping of groundwater. Pinellas County is better placed in this regard than Hillsborough or Pasco counties because of its lower karst component. The city with the highest likelihood of risk is Tampa, probably because of its massive urbanization over the last 20 yr. Coastal cities most at risk from sinkhole effects on housing are New Port Richey and Hudson, but they are a very distant second and third compared to Tampa. Economic damage risks to housing are estimated to be about $5 million/yr for Tampa and are probably going to increase in the near future if the current trends of population increase and demands on the aquifer system's water are to continue. Copyright © 2005. The American Association of Petroleum Geologists/Division of Environmental Geosciences. All rights reserved.
Florida is riddled with sinkholes due to its karst topography. Sometimes these sinkholes can cause extensive damage to infrastructure and homes. It has been suggested that agricultural practices, such as sprinkler irrigation methods used to protect crops, can increase the development of sinkholes, particularly when temperatures drop below freezing, causing groundwater levels to drop quickly during groundwater pumping. In the strawberry growing region, Dover/Plant City, Florida, the effects have caused water shortages resulting in dry- wells and ground subsidence through the development of sinkholes that can be costly to maintain and repair. In this study, we look at how frost-freeze events have affected West Central Florida over the past 25 years with detailed comparisons made between two cold-years (with severe frost-freeze events) and a warm year (no frost-freeze events). We analyzed the spatial and temporal correlation between strawberry farming freeze protection practices and the development of sinkholes/dry well complaints, and assessed the economic impact of such events from a water management perspective by evaluating the cost of repairing and drilling new wells and how these compared with using alternative crop-protection methods. We found that the spatial distribution of sinkholes was non-random during both frost-freeze events. A strong correlation between sinkhole occurrence and water extraction and minimum temperatures was found. Furthermore as temperatures fall below 41°F and water levels decrease by more than 20 ft, the number of sinkholes increase greatly (N >10). At this time alternative protection methods such as freeze-cloth are cost prohibitive in comparison to repairing dry wells. In conclusion, the findings from this study are applicable in other agricultural areas and can be used to develop comprehensive water management plans in areas where the abstraction of large quantities of water occur.
The central Ebro Basin comprises thick evaporite materials whose high solubility produces typically karstic landforms. The sinkhole morphology developed in the overlying alluvium has been studied using gravimetry and ground-penetrating radar (GPR) on stream terraces, as well as analyzing the evolution of sinkhole morphologies observed in aerial photographs taken in 1928, 1957, and 1985. The sinkhole morphologies give some idea of possible subsurface processes as well as an indication of the final mechanisms involve in sinkhole development. On stream terraces and cover pediments the most commonly encountered dolines are bowl-shaped in their morphology with both diffuse and scarped edges. In contrast, dolines developed in the gypsiferous silt infilled valleys have a funnel and well-shaped morphology. The diffuse-edged bowl-shaped dolines are developed through the progressive subsidence of the alluvial cover, due to washing down of alluvial particles through small voids and cracks into deeper subsurface caves, resulting in a decrease alluvial density. Future compaction of the alluvial cover will produce surface subsidences. This type of dolines are associated with negative gravity anomalies. In contrast, the scarped-edge dolines are formed by the sudden collapse of a cavity roof. The cavities and cracks formed in the gypsum karst may migrate to the surface through the alluvial deposits by piping, and they may subsequently collapse. In this instance, the cavities can be detected by both gravity and GPR anomalies where the voids are not deeper than 4–5 m from the surface. These processes forming sinkholes can be enhanced by man-induced changes in the groundwater hydrologic regime by both inflows, due to irrigation, ditch losses, or pipe leakages, and by outflows from pumping activities.
The relation between sinkhole density and water quality was investigated in seven selected carbonate aquifers in the eastern United States. Sinkhole density for these aquifers was grouped into high (>25 sinkholes/100 km2), medium (1–25 sinkholes/100 km2), or low (2) categories using a geographical information system that included four independent databases covering parts of Alabama, Florida, Missouri, Pennsylvania, and Tennessee. Field measurements and concentrations of major ions, nitrate, and selected pesticides in samples from 451 wells and 70 springs were included in the water-quality database. Data were collected as a part of the US Geological Survey (USGS) National Water-Quality Assessment (NAWQA) Program. Areas with high and medium sinkhole density had the greatest well depths and depths to water, the lowest concentrations of total dissolved solids and bicarbonate, the highest concentrations of dissolved oxygen, and the lowest partial pressure of CO2 compared to areas with low sinkhole density. These chemical indicators are consistent conceptually with a conduit-flow-dominated system in areas with a high density of sinkholes and a diffuse-flow-dominated system in areas with a low density of sinkholes. Higher cave density and spring discharge in Pennsylvania also support the concept that the high sinkhole density areas are dominated by conduit-flow systems. Concentrations of nitrate-N were significantly higher (p
The real west-central Florida is far from the "Sunshine State" image of white sand beaches and palm trees. Gently rolling hills, dense jungle-like forests, pine and palmetto scrublands, impenetrable cypress swamps, and alligator-laden rivers are more common. Numerous crystal-clear springs offer a glimpse of the hidden world below - a world that could challenge the most imaginative Disney artists (Fig. 6.17).
Development of induced sinkholes in carbonate terranes has resulted in costly damage and water pollution. The states most impacted are Alabama, Florida, Georgia, Missouri, Pennsylvania, and Tennessee. Induced sinkholes are of 2 types: those resulting from a decline in water level due to ground-water withdrawals and those resulting from construction. Alternatives that allow avoiding or minimizing sinkhole hazards are most numerous when a problem or potential problem is recognized during site evaluation. The number of alternatives declines after the beginning of site development. Where sinkhole development is predictable, zoning of land-use can minimize hazards.-from Author
This paper presents a brief review of the values and vulnerability of karst systems, and specifically examines issues of water balance, physical destruction, sedimentation and pollution. It then outlines key issues in the protection of karst and the need for continuing vigilance.
A 1995 biological inventory of 8 northwestern Georgia caves documented or re-confirmed the presence of 46 species of invertebrates, 35 considered troglobites or troglophiles. The study yielded new cave records for amphipods, isopods, diplurans, and carabid beetles. New state records for Georgia included a pselaphid beetle. Ten salamander species were in the 8 caves, including a true troglobite, the Tennessee cave salamander. Two frog, 4 bat, and 1 rodent species were also documented. One cave contained a large colony of gray bats. For carabid beetles, leiodid beetles, and millipeds, the species differed between the caves of Pigeon and Lookout Mountain. Diplurans were absent from Lookout Mountain caves, yet were present in all Pigeon Mountain caves. A comparison between 1967 and 1995 inventories of Pettijohns Cave noted the absence of 2 species of drip pool amphipods from the latter. One cave had been contaminated by a petroleum spill and the expected aquatic fauna was not found. Further inventory work is suggested and the results should be applied to management strategies that provide for both biodiversity protection and recreational cave use.
A thorough understanding of a lake's hydrology is essential for many lake studies. In some situations the interactions between groundwater systems and lakes are complex; in other cases the hydrology of a multilake system needs to be quantified. In such places, stable isotopes offer an alternative to the more traditional piezometer networks, which are costly to install and time-consuming to maintain. The stable-isotope mass-balance relations presented here can be used to estimate groundwater exchange rates for individual lakes and geographically clustered lakes. These relations also can be used to estimate other hydrological factors, such as average relative humidity. In places where the groundwater system is unstable (e.g., where flow reversals occur), natural solute tracers may provide a better alternative than stable isotopes for estimating rates of groundwater flow to and from lakes.
This study was conducted to develop a better understanding of the hydrology in a drained forest. Data collected from a field study on an intensively monitored forest watershed are presented to describe the system's hydrologic components. The watershed is a 15-year-old loblolly pine (Pinus taeda) plantation located in the coastal plain region of North Carolina. The site is characterized by shallow water table soils (thermic typic umbraquults) which are drained with open ditches about 100 m apart. Water balances based on field measurements were conducted for various time frames during the two-year study period. Closure errors for the water balances were typically within 10% for longer time periods. Hydrologic components with characteristics unique to forest watersheds, including canopy interception loss, soil drainage, and forest evapotranspiration, were analyzed by examining different interactions among vegetation, soil, and meteorology. Canopy interception loss was measured to be up to 35% of the gross precipitation for unthinned stand conditions. Soil drainage was measured to be 42% of the gross rainfall in the winter and early spring months. For the water balances calculated, average evapotranspiration rates ranged from 1.4 mm/day for winter months to 4.1 mm/day for summer months. The field data and analysis procedures adequately described the hydrologic components of the forest system.
A new 1:1 million scale, lithology-based, digital karst map has been constructed for the Appalachian region. This map is serving as the nucleus for a new national karst map and as a test for methodologies used in developing the national karst map and data base. The map comprises data compiled from various state and regional sources. Issues encountered in the compilation process include unevenness between the vari-ous data sets in resolution, lithologic description, and classification. Regional geologic and karst data sets providing information on glacial deposits and cave and sinkhole locations are valuable components of the compilation and may also be used as tools for testing the validity of portions of the map and for creating derived products such as karst density maps. Compilation of the national karst map will become more dif-ficult as it progresses to include semi-arid western states that contain evaporate karst, karst aquifers, karstic features propagated from buried evaporites into surface rocks of non-karstic lithology, and various features analogous to karst.
Best estimates of evaporation at Williams Lake, north central Minnesota, were determined by the energy budget method using optimum sensors and optimum placement of sensors. These best estimates are compared with estimates derived from using substitute data to determine the effect of approximately biweekly periods using five open water seasons. For most of the data substitutions that affected the Bowen ratio, new values of evaporation differed little from best estimates. The three data substitution methods that caused the largest deviations from the best evaporation estimates were (1) using changes in the daily average surface water temperature as an indicator of the lake heat storage term, (2) using shortwave radiation, air temperature, and atmospheric vapor pressure data from a site 110 km away, and (3) using an analog surface water temperature probe. Recalculations based on these data substitutions resulted in differences from the best estimates as much as 89%, 21%, and 10%, respectively. The data substitution method that provided evaporation values that most clearly matched the best estimates was measurement of the lake heat storage term at one location in the lake, rather than at 16 locations. Evaporation values resulting from this substitution method usually were within 2% of the best estimates.
Estimates of downward leakage from Florida lakes with and without outlets suggest that conventional nutrient-loading models are inappliable to any lake not in a watertight rock basin. Downward leakage is measurable during months when lake level falls by an amount exceeding the net precipitation deficiency. To measure it, USGS stage data for 20 lakes from north, central, and south sectors of the peninsula were compared with three 32-yr sets of mean monthly meteorologic measurements. Monthly pan-evaporation data were converted to lake evaporation by factors estimated at Lake Okeechobee. Leakage estimates (geometric means) range from 28.4 to 50.9 cm yr-1 in 18 of 20 lakes; two exceptionally astatic lakes gave 90.1 and 141.2 cm yr-1. Presence of outlets in 15 of 20 lakes makes no detectable difference in leakage. Adding evaporative losses (and ignoring surface outflow if any), residence times for the 20 lakes averaged 2.67±1.33 yr. -from Author
A three-dimensional groundwater flow and solute transport model was calibrated to a plume of water described by measurements of δ¹â¸O and used to calculate groundwater inflow and outflow rates at a lake in northern Wisconsin. The flow model was calibrated to observed hydraulic gradients and estimated recharge rates. Calibration of the solute transport submodel to the configuration of a stable isotope (¹â¸O) plume in the contiguous aquifer on the downgradient side of the lake provides additional data to constrain the model. A good match between observed and simulated temporal variations in plume configurations indicates that the model closely simulated the dynamic of the real system. The model provides information on natural variations of rates of groundwater inflow, lake water outflow, and recharge to the water table. Inflow and outflow estimates compare favorably with estimates derived by the isotope mass balance method. Model simulations agree with field observations that show groundwater inflow rates are more sensitive to seasonal variations in recharge than outflow.
The parameter identification process referred to as the ‘inverse’ method has been applied at the hillslope scale, to quantify the hydrologic characteristics of two catchments in Western Australia. The physically based numerical model HILLS was used. Despite the limitations imposed by using a model which of necessity contains several simplifying assumptions, in contrast to the high level of complexity within the soil profile, an encouraging level of representation is achieved. It has also been shown that water-level data from shallow wells provide a promising method for determination of the average or ‘effective’ values of vertical and horizontal hydraulic conductivity, soil porosity and rates of evaporation. The model has also provided an estimate of the various sources of stormflow — surface, subsurface, ground water — that occurs during and after a rainstorm.
This paper reports a set of model performance calculations for three event-based rainfall-runoff models on three data sets in involving 269 events from small upland catchments. The models include a regression model, a unit hydrograph model, and a quasi-physically based model. The catchments are from the Washita River Experimental Watershed, Oklahoma; the Mahantango Creek Experimental Watershed, Pennsylvania; and the Hubbard Brook Experimental Forest, New Hampshire. -from Authorsunit hydrograph Oklahoma Pennsylvania New Hampshire
An approach to the global estimation of water balance elements and their spatial distribution using GIS is presented. It is primarily related to the catchments where measured data are scarce and the spatial differentiation of the hydrological characteristics is not possible without climatological data. Emphasis is placed on estimating the water balance of transboundary karstic aquifers, where problems concerning the hydrometeorological data, catchment boundaries and determination of water balance elements in general are far more complex. The runoff estimation was done using the Turc and Langbein methods, which are the most frequently applied in this region. The years 1961–1990 were used as the reference period. Based on comparison of the results, the applicability of the methods is discussed. The approach proposed is suitable for estimation of water balance in the study area and may also be applied in a wider region.
In 1930, a canal was excavated to connect the Lesina Lagoon with the Adriatic Sea, modifying the track of the previous existing Acquarotta canal. The 1100. m long stretch of the canal situated next to the coast exposed unknown highly cavernous gypsum bedrock underlying a loose sandy cover. During the last two decades, a large number of cover collapse and cover suffosion sinkholes have formed along two bands situated next to the canal, impinging the adjacent Lesina Marina residential area. The area affected by subsidence has increased exponentially from 1999 to 2009. The tight spatial correlation between the sinkholes and the canal reveals that the subsidence phenomenon has been induced by the local hydrogeological changes caused by the canal in the coastal evaporite aquifer: (1) Local lowering of the average water table. (2) Deflection of the groundwater flow lines towards the canal and increase in flow velocity. (3) Amplification of the groundwater level oscillations, largely controlled by the tidal regime. (4) Local reversals in the groundwater flow, changing the canal temporarily from effluent to influent. These changes in the hydrogeological functioning of the system have favoured both internal erosion and karstification processes. Hydrochemical evidence reveals that gypsum dissolution is a currently active process favoured by fresh water and sea water mixing and cation-exchange processes. Most likely, the partial replacement of a concrete lining in the canal by pervious gabions in 1993 provided more adequate conditions for the evacuation of the sediments filling the karst conduits, accelerating internal erosion and sinkhole development.
Williams Lake, Minnesota is a closed-basin lake that is a flow-through system with respect to ground water. Ground-water input represents half of the annual water input and most of the chemical input to the lake. Chemical budgets indicate that the lake is a sink for calcium, yet surficial sediments contain little calcium carbonate. Sediment pore-water samplers (peepers) were used to characterize solute fluxes at the lake-water–ground-water interface in the littoral zone and resolve the apparent disparity between the chemical budget and sediment data. Pore-water depth profiles of the stable isotopes δ18O and δ2H were non-linear where ground water seeped into the lake, with a sharp transition from lake-water values to ground-water values in the top 10 cm of sediment. These data indicate that advective inflow to the lake is the primary mechanism for solute flux from ground water. Linear interstitial velocities determined from δ2H profiles (316 to 528 cm/yr) were consistent with velocities determined independently from water budget data and sediment porosity (366 cm/yr). Stable isotope profiles were generally linear where water flowed out of the lake into ground water. However, calcium profiles were not linear in the same area and varied in response to input of calcium carbonate from the littoral zone and subsequent dissolution. The comparison of pore-water calcium profiles to pore-water stable isotope profiles indicate calcium is not conservative. Based on the previous understanding that 40–50 % of the calcium in Williams Lake is retained, the pore-water profiles indicate aquatic plants in the littoral zone are recycling the retained portion of calcium. The difference between the pore-water depth profiles of calcium and δ18O and δ2H demonstrate the importance of using stable isotopes to evaluate flow direction and source through the lake-water–ground-water interface and evaluate mechanisms controlling the chemical balance of lakes. Published in 2003 by John Wiley & Sons, Ltd.
Evaluation of hydrologic methodology used in a number of water balance studies of lakes in the United States shows that most of these studies calculate one or more terms of the budget as the residual. A literature review was made of studies in which the primary purpose was error analysis of hydrologic measurement and interpretation. Estimates of precipitation can have a wide range of error, depending on the gage placement, gage spacing, and areal averaging technique. Errors in measurement of individual storms can be as high as 75 percent. Errors in short term averages are commonly in the 15-30 percent range, but decrease to about 5 percent or less for annual estimates. Errors in estimates of evaporation can also vary widely depending on instrumentation and methodology. The energy budget is the most accurate method of calculating evaporation; errors are in the 10–15 percent range. If pans are used that are located a distance from the lake of interest, errors can be considerable. Annual pan-to-lake coefficients should not be used for monthly estimates of evaporation because they differ from the commonly used coefficient of 0.7 by more than 100 percent. Errors in estimates of stream discharge are often considered to be within 5 percent. If the measuring section, type of flow profile, and other considerations, such as stage discharge relationship, are less than ideal errors in estimates of stream discharge can be considerably greater than 5 percent. Errors in estimating overland (nonchannelized) flow have not been evaluated, and in most lake studies this component is not mentioned. Comparison of several lake water balances in which the risdual consists solely of errors in measurement, shows that such a residual, if interpreted as ground water, can differ from an independent estimate of ground water by more than 100 percent.
Surface-water bodies are integral parts of groundwater flow systems. Groundwater interacts with surface water in nearly all landscapes, ranging from small streams, lakes, and wetlands in headwater areas to major river valleys and seacoasts. Although it generally is assumed that topographically high areas are groundwater recharge areas and topographically low areas are groundwater discharge areas, this is true primarily for regional flow systems. The superposition of local flow systems associated with surface-water bodies on this regional framework results in complex interactions between groundwater and surface water in all landscapes, regardless of regional topographic position. Hydrologic processes associated with the surface-water bodies themselves, such as seasonally high surface-water levels and evaporation and transpiration of groundwater from around the perimeter of surface-water bodies, are a major cause of the complex and seasonally dynamic groundwater flow fields associated with surface water. These processes have been documented at research sites in glacial, dune, coastal, mantled karst, and riverine terrains.
The paper presents the results of a study aimed at determining the water balance of small dredging lakes located in the temperate climatic zone (southern Austria) and their impact on the adjacent groundwater field using heavy stable isotopes of water, deuterium and oxygen-18. The isotope method of determining water balance of groundwater-controlled lakes was examined in some detail using the field data collected during this study. The calculations performed for different sets of input data revealed that the approach recommended in the literature, i.e. the use of oxygen-18 data, the air-based temperatures and the mean isotopic composition of evaporation flux calculated from the annual mean isotopic composition of precipitation assuming isotope equilibrium at the ground-level temperature, may lead to groundwater inflow rates which are underestimated by as much as 40%. The isotope-mass balance calculations performed independently for deuterium and oxygen-18 data can be reconciled within the overall uncertainty of the method, when the surface water temperature of a lake (with relative humidity adjusted accordingly) is used instead of ground-level air temperature, and the isotopic composition of the evaporation flux is adequately averaged, taking into account the seasonal variability of this flux for the given lake system.
Typescript. Thesis (M. Eng.)--University of Florida, 1986. Vita. Includes bibliographical references (leaves 206-210).
The relationship between deuterium and oxygen-18 concentrations in natural meteoric waters from many parts of the world has
been determined with a mass spectrometer. The isotopic enrichments, relative to ocean water, display a linear correlation
over the entire range for waters which have not undergone excessive evaporation.
Index and short description of the geologic terms used by the GSS: Bulletin of the Georgia Speleological Survey
- C Anderson
Anderson, C., 1993, Index and short description of the geologic terms used
by the GSS: Bulletin of the Georgia Speleological Survey, v. 25,
p. 4-8.
Monitoring the water balance of a natural wetland
- G M Chescheir
- D M Amatya
- R W Skaggs
Chescheir, G.M., Amatya, D.M., and Skaggs, R.W., 1995, Monitoring the
water balance of a natural wetland, in Cambell, K.L., ed., Versatility
of Wetlands in the Agricultural Landscape: St. Joseph, Michigan,
American Society of Agricultural Engineers, p. 451-462.
Estimation of downward leakage from Florida lakes: Limnology and Oceanography
- S E Deevey
- Jr
Deevey, S.E., Jr., 1988, Estimation of downward leakage from Florida
lakes: Limnology and Oceanography, v. 33, no. 6, p. 1308-1320.
Water Budgets: Foundations for Effective Water-Resources and Environmental Management: US Geological Survey, Circular 1308
- R W Healy
- T C Winter
- J W Labaugh
- O L Franke
Healy, R.W., Winter, T.C., LaBaugh, J.W., and Franke, O.L., 2007,
Water Budgets: Foundations for Effective Water-Resources and
Environmental Management: US Geological Survey, Circular 1308,
90 p.
Selected Karst Features of the Central Valley and Ridge Province: Virginia Division of Mineral Resources
- D A Hubbard
- Jr
Hubbard, D.A., Jr., 1988, Selected Karst Features of the Central Valley
and Ridge Province: Virginia Division of Mineral Resources,
Publication 83, 1:250,000 scale map with text.
Deep southern caves: National Geographic Magazine
- M Jenkins
Jenkins, M., 2009, Deep southern caves: National Geographic Magazine,
June, 2009, p. 124-141.
Experimental determination of the hydrologic components of a drained forest watershed: Transactions of the ASABE
- E J Mccarthy
- R W Skaggs
- P Farnum
McCarthy, E.J., Skaggs, R.W., and Farnum, P., 1991, Experimental
determination of the hydrologic components of a drained forest
watershed: Transactions of the ASABE, v. 34, no. 5, p. 2031-2039.
Restoring a disappearing lake: Land and Water
- G Penson
Penson, G., 2002, Restoring a disappearing lake: Land and Water, v. 46,
no. 5, p. 1-10.
Hydrogeology and Groundwater Quality of Highlands County
- R M Spechler
Spechler, R.M., 2010, Hydrogeology and Groundwater Quality of
Highlands County, Florida: U.S. Geological Survey Scientific
Investigations Report 2010-5097, 84 p.
Climate Change and Variations: A Primer for Teachers, v. 1, National Council for Geographic Education
- D Winstanley
- W M Wendland
Winstanley, D., and Wendland, W.M., 2007, Climate change and
associated changes to the water budget, in Dando, W.A., ed., Climate
Change and Variations: A Primer for Teachers, v. 1, National Council
for Geographic Education, Pathways in Geography 35.
Ecosystem Approach to Aquatic Ecology: Mirror Lake and its Environment
- T C Winter
Winter, T.C., 1985, Approaches to the study of lake hydrology, in Likens,
G.E., ed., Ecosystem Approach to Aquatic Ecology: Mirror Lake and
its Environment, p. 128-135.