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Bloomington, IN, United States

Naylor S.,Center for Geospatial Data Analysis | Olyphant G.A.,Indiana University | Branam T.D.,Indiana Geological Survey
Joint Mining Reclamation Conf. 2010 - 27th Meeting of the ASMR, 12th Pennsylvania Abandoned Mine Reclamation Conf. and 4th Appalachian Regional Reforestation Initiative Mined Land Reforestation Conf. | Year: 2010

The use of coal combustion by-products (CCBs) in mine reclamation has been advocated by some because of their low permeability and potential to generate alkalinity. However, others have argued that these benefits are outweighed by the potential for leaching of trace elements that can enter ground and surface waters. In 1996, an abandoned mine land (AML) site in southwestern Indiana was reclaimed using ponded ash as structural fill in highwall cuts, and fixated scrubber sludge (FSS) as capping material over pyritic refuse. Prereclamation and post-reclamation monitoring of surface water discharge from the site, groundwater elevations and chemistry, as well as soil moisture fluctuations in the unsaturated zone have provided a basis for evaluating the effects of CCBs on the hydrochemistry of the site and potential for off-site impacts. Limited recharge through the FSS is supported by barometric efficiency changes in the refuse aquifer, the presence of perched water measured in monitoring wells installed on the cap, and minimal fluctuations in soil moisture within and immediately below the cap. Reductions in oxygenated rainwater reaching the refuse are indicated by groundwater chemistry data, collected from the refuse aquifer between 1995 and 2007, which show an increase in pH along with decreasing trends in total acidity, specific conductivity (SpC), and arsenic. Concentrations of boron, a trace element commonly associated with CCBs, have declined to near pre-reclamation levels at most sites (~1 mg/L) after an increase immediately following reclamation. Although arsenic concentrations at 14 μg/L (EPA maximum contaminant level, or MCL, is 10 μg/L) along with boron (14 mg/L) remain slightly elevated in groundwater associated with ash-filled lakes, improvements in surface water quality leaving the site include significant reductions in total mineral acidity and total iron concentrations, while trace metal concentrations remain below EPA MCLs. Copyright © (2010) by the American Society of Mining and Reclamation. Source

Ficklin D.L.,Indiana University Bloomington | Ficklin D.L.,Center for Geospatial Data Analysis | Robeson S.M.,Indiana University Bloomington | Knouft J.H.,Saint Louis University
Geophysical Research Letters | Year: 2016

Characterizing the impacts of climatic change on hydrologic processes is critical for managing freshwater systems. Specifically, there is a need to evaluate how the two major components of streamflow, baseflow and stormflow, have responded to recent trends in climate. We derive baseflow and stormflow for 674 sites throughout the United States from 1980 to 2010 to examine their associations with precipitation, potential evapotranspiration, and maximum/minimum temperature. The northeastern (NE) and southwestern (SW) United States display consistent trends in baseflow and stormflow: increasing during fall and winter in the NE and decreasing during all seasons in the SW. Trends elsewhere and at other times of the year are more variable but still associated with changes in climate. Counter to expectations, baseflow and stormflow trends throughout the United States tend to change concurrently. These trends are primarily associated with precipitation trends, but increases in PET are influential and likely to become important in the future. ©2016. American Geophysical Union. All Rights Reserved. Source

Ficklin D.L.,Indiana University | Ficklin D.L.,Center for Geospatial Data Analysis | Barnhart B.L.,U.S. Department of Agriculture | Knouft J.H.,Saint Louis University | And 4 more authors.
Hydrology and Earth System Sciences | Year: 2014

Water temperature is a primary physical factor regulating the persistence and distribution of aquatic taxa. Considering projected increases in air temperature and changes in precipitation in the coming century, accurate assessment of suitable thermal habitats in freshwater systems is critical for predicting aquatic species' responses to changes in climate and for guiding adaptation strategies. We use a hydrologic model coupled with a stream temperature model and downscaled general circulation model outputs to explore the spatially and temporally varying changes in stream temperature for the late 21st century at the subbasin and ecological province scale for the Columbia River basin (CRB). On average, stream temperatures are projected to increase 3.5 °C for the spring, 5.2 °C for the summer, 2.7 °C for the fall, and 1.6 °C for the winter. While results indicate changes in stream temperature are correlated with changes in air temperature, our results also capture the important, and often ignored, influence of hydrological processes on changes in stream temperature. Decreases in future snowcover will result in increased thermal sensitivity within regions that were previously buffered by the cooling effect of flow originating as snowmelt. Other hydrological components, such as precipitation, surface runoff, lateral soil water flow, and groundwater inflow, are negatively correlated to increases in stream temperature depending on the ecological province and season. At the ecological province scale, the largest increase in annual stream temperature was within the Mountain Snake ecological province, which is characterized by migratory coldwater fish species. Stream temperature changes varied seasonally with the largest projected stream temperature increases occurring during the spring and summer for all ecological provinces. Our results indicate that stream temperatures are driven by local processes and ultimately require a physically explicit modeling approach to accurately characterize the habitat regulating the distribution and diversity of aquatic taxa. Source

Ficklin D.L.,Indiana University | Ficklin D.L.,Center for Geospatial Data Analysis | Maxwell J.T.,Indiana University | Letsinger S.L.,Center for Geospatial Data Analysis | Gholizadeh H.,Indiana University
Environmental Research Letters | Year: 2015

We present high spatial-resolution trends of the Palmer drought severity index (PDSI), potential evapotranspiration (PET), and selected climate variables from 1979-2013 for the contiguous United States in order to gain an understanding of recent drought trends and their climatic forcings. Based on a spatial grouping analysis, four regions of increasing (upper Midwest, Louisiana, southeastern United States (US), and western US) and decreasing (New England, Pacific Northwest, upper Great Plains, and Ohio River Valley) drought trends based on Mann-Kendall Z values were found. Within these regions, partial correlation and multiple regression for trends in climate variables and PDSI were performed to examine potential climatic controls on these droughts. As expected, there was a US-wide concurrence on drought forcing by precipitation. However, there was correspondence of recent PET trends with recent drought trends in many regions. For regions with an increase in recent droughts, average air temperature was generally the second most important variable after precipitation in determining recent drought trends. Across the regions where recent drought trends are decreasing, there was no clear ranking of climate-variable importance, where trends in average temperature, specific humidity and net radiation all played significant regional roles in determining recent drought trends. Deconstructing the trends in drought show that, while there are regions in the US showing positive and negative trends in drought conditions, the climate forcings for these drought trends are regionally specific. The results of this study allow for the interpretation of the role of the changing hydroclimatic cycle in recent drought trends, which also have implications for the current and impending results of climate change. © 2015 IOP Publishing Ltd. Source

Ficklin D.L.,Indiana University | Ficklin D.L.,Center for Geospatial Data Analysis | Letsinger S.L.,Center for Geospatial Data Analysis | Gholizadeh H.,Indiana University | Maxwell J.T.,Indiana University
Computers and Geosciences | Year: 2015

Calculating the Palmer Drought Severity Index (PDSI) using the Thornthwaite potential evapotranspiration (PET) method has come under recent scrutiny for overestimating drought conditions when air temperatures exceed the historical baseline. With increasing air temperatures around the world, calculating the PDSI using the Thornthwaite PET method may no longer be the appropriate option. Therefore, various researchers have called for the use of the physically-based Penman-Monteith PET method to estimate PDSI. We present an addition to the PDSI tool developed by Jacobi et al. (2013) that includes an option to use the Penman-Monteith method to calculate PET as an input to the PDSI calculations. Comparisons with a global PDSI dataset also estimated using the Penman-Monteith method indicate good spatial correlation. This addition to the Jacobi et al. (2013) tool allows users to easily calculate a suite of Palmer drought indices using Penman-Monteith potential evapotranspiration for current and future drought projections at any spatial scale. © 2015 Elsevier Ltd. Source

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