An approach to hydrogeological modeling of a large system of groundwater-fed lakes and wetlands in the Nebraska Sand Hills, USA

Rossman, NathanR.; Zlotnik, VitalyA.; Rowe, ClintonM.

An approach to hydrogeological modeling of a large system of groundwater-fed lakes and wetlands in the Nebraska Sand Hills, USA | Approche par modélisation hydrogéologique d’un vaste système de lacs et de zones humides alimentés par des eaux souterraines dans les Sand Hills du Nebraska, Etats-Unis d’Amérique Un enfoque para la modelización hidrogeológica de un gran sistema de lagos y humedales alimentados por agua subterránea en Nebraska Sand Hills, EE UU 美国内布拉斯加州Sand Hills地区地下水补给的湖泊和湿地巨大系统的水文地质模拟方法 Uma abordagem para modelagem hidrogeológica de um amplo sistema de lagos e zonas húmidas alimentados por águas subterrâneas em Nebraska Sand Hills, EUA

2018

Rossman, NathanR. | Zlotnik, VitalyA. | Rowe, ClintonM.

The feasibility of a hydrogeological modeling approach to simulate several thousand shallow groundwater-fed lakes and wetlands without explicitly considering their connection with groundwater is investigated at the regional scale (~40,000 km²) through an application in the semi-arid Nebraska Sand Hills (NSH), USA. Hydraulic heads are compared to local land-surface elevations from a digital elevation model (DEM) within a geographic information system to assess locations of lakes and wetlands. The water bodies are inferred where hydraulic heads exceed, or are above a certain depth below, the land surface. Numbers of lakes and/or wetlands are determined via image cluster analysis applied to the same 30-m grid as the DEM after interpolating both simulated and estimated heads. The regional water-table map was used for groundwater model calibration, considering MODIS-based net groundwater recharge data. Resulting values of simulated total baseflow to interior streams are within 1% of observed values. Locations, areas, and numbers of simulated lakes and wetlands are compared with Landsat 2005 survey data and with areas of lakes from a 1979–1980 Landsat survey and the National Hydrography Dataset. This simplified process-based modeling approach avoids the need for field-based morphology or water-budget data from individual lakes or wetlands, or determination of lake-groundwater exchanges, yet it reproduces observed lake-wetland characteristics at regional groundwater management scales. A better understanding of the NSH hydrogeology is attained, and the approach shows promise for use in simulations of groundwater-fed lake and wetland characteristics in other large groundwater systems.

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