"A PLANT, A BUG, AND A BUNCH OF HYDROGEOLOGISTS MEET IN A SALINE WETLAND..."

Eastern Nebraska's saline wetlands are home to several unique species including, endangered - salt wort (Salicornia ruba), and the Salt Creek tiger beetle (Cicindela nevadica lincolniana). Urban encroachment has reduced the saline footprint, as channelization's resultant down-cutting of traversing streams has caused a decline in wetland water tables, altering flow paths which historically transported saline water upward to discharge at the land surface. These alterations have induced a decrease in beetle population which has waned to a few hundred individuals occupying three sites. To better manage these wetlands, preserve their unique flora, and increase their beetle population, management plans require mapping of the extent of the hydrologic reach beneath these wetlands and adjacent uplands, delineation of the physical and chemical interactions between surface water and shallow groundwater, and details of beetle-habitat interactions. Past hydrogeologic studies were focused on the hydrogeochemical dynamics of deeper, saline groundwater in the Dakota Aquifer and its migration to, and discharge at the surface where it provides the vital soil and surface water salinity to sustain the ecosystem. New hydrologic studies at wetland sites near the city of Lincoln aim to quantify beetle-hydrology-habitat interactions, characterize shallow vertical and lateral groundwater flow and salt transport within the alluvium atop the Dakota Formation, and determine temporal and spatial variations in stream water salinity, and in channel bank and sand bar soil moisture and salinity due to saline groundwater seepage into the streams (see additional abstracts in this session). Results from these studies will be combined with data from previous studies to develop a conceptual model of the mixing relationships between deep-source saline groundwater, shallow fresh groundwater moving within the alluvium, surface water within Rock, Salt, and Little Salt Creeks, and local precipitation, and to assess how these hydrologic interactions impact beetle habitat and behavior. This new model will assist Lincoln, area Natural Resource District, and Nebraska Game and Parks Commission wetland managers in making more informed and effective plans for saline ecosystem management, and tiger beetle preservation and reintroduction.