CGDA Projects
  
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Evaluating tillage practices on near-surface groundwater recharge

Issue

A previously funded project (2014-2015) developed an outdoor laboratory in a small subwatershed in Indiana (School Branch watershed, Hendricks County, Indiana), which is being used to collect data sufficient to develop a complete water budget (micrometeorological, soil, subsurface- and surface-water components) and accurately quantify fluxes directed toward the saturated zone as opposed to surface runoff. These sites are located in agricultural settings managed by conservation tillage practices. These sites were added to the Indiana Water Balance Network (http://igs.indiana.edu/CGDA/waterBalanceNetwork.cfm). In evaluating the early results of the installed instrumentation, two important questions have arisen that we will address: a. Is the behavior of surface infiltration and near-surface recharge dependent on the management of the land? For the currently installed sites, soil moisture and groundwater fluxes are very responsive to surface boundary conditions. Is that responsive behavior governed by the surficial geology, or do tillage practices play a role? b. Is a trench installation disruptive to the measurement of in situ soil moisture, or is a borehole sensor preferable to observe ambient conditions?

Objective

The goals of this project are to install sensors and monitor the resultant water-balance data in different areas of the small watershed being subjected to different land-management (particularly agricultural) practices. Over time, statistically significant differences in the sites might be able to be linked back to how the land is managed.

Contact: Shawn Naylor (snaylor@indiana.edu)



Pilot Program to Evaluate using Chloride as a Tracer for Estimating Recharge Rates

Issue

There are methods for estimating the proportion of groundwater contribution to stream flow through hydrograph separation methods, but these methods do not provide rates of groundwater recharge to the subsurface. Tritium has been used in a handful of locations in Indiana to determine recharge rates, but the technique is no longer useful because of the short half-life and time since bomb testing in the 1960s. Chloride has been used successfully in semi-arid to arid regions by measuring the concentration in water and soil water below the root zone. Chloride infiltrates into the ground by atmospheric deposition from the oceans (more is deposited near the coasts, less inland), and is conservative because it is not taken up by vegetation.

Objective

Collect sediment samples and analyze them for chloride and conduct a mass balance to determine the rate of groundwater recharge.

Contact: Sally Letsinger (sletsing@indiana.edu)



Spatial analysis of significant water withdrawal facilities in Indiana

Issue

The issue of water-resources planning is coming to the forefront in Indiana. Early reconnaissance studies have indicated that incomplete or inaccurate databases might inhibit studies that rely on those data. Therefore, examination of existing databases and creation of new, targeted, and relevant databases related to water resources are needed in Indiana.

Objective

This project will support the larger effort of improving the data accuracy in databases important to water resources planning in Indiana.

Contact: Sally Letsinger (sletsing@indiana.edu)



The Indiana Water Balance Network (IWBN)

Issue

Climate change with its associated droughts and floods highlight the need to improve our understanding of water budgets in Indiana to facilitate improved water-resource planning.

Objective

The Indiana Water Balance Network (IWBN) was developed to monitor trends in water loss and gain for different components of the hydrologic cycle in various hydrogeologic settings.

Contact: Sally Letsinger (sletsing@indiana.edu)



Unsaturated-zone hydrology of glacial hydrogeologic settings in Indiana

Issue

Understanding water movement through the unsaturated zone is essential to maximizing agricultural productivity, minimizing flood impacts, limiting contaminant transport to aquifers, and elucidating potential climate-change impacts on Indiana’s water resources.

Objective

Unsaturated zone data from monitoring sites in eight unique glacial hydrogeologic settings are processed and analyzed to better understand rates of water movement toward underlying aquifers and adjacent surface water bodies.

Contact: Sally Letsinger (sletsing@indiana.edu)





Michael Daniels
 
 
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