Groundwater levels in Nebraska not only slowed their decline in many areas, they actually rose in parts of the state from 2006 to spring 2007.
Above-normal precipitation after seven years of drought, well-timed rains and more efficient irrigation practices all may be factors in the relatively good news reflected on the latest groundwater level map, says Mark Burbach, an assistant geoscientist in UNL's School of Natural Resources.
One-year increases were particularly notable along the Platte River, from Columbus to Fremont, south into Butler and Saunders counties and north into Dodge County. Increases also were recorded in central Nebraska along the Platte and Republican rivers.
The most recent groundwater level monitoring map shows groundwater level changes from spring 2006 to spring 2007. Others maps record levels from the earliest records to spring 2007, and from 2000 to spring 2007. There also is an updated map of the density of irrigation wells across the state is also available.
Maps from previous years are archived at the Web site, dating to 1954.
"These maps are the way we check the health of our hydrologic resources at annual intervals," says Mike Jess, associate director of the UNL Water Center.
Maps can be downloaded free from the SNR's Web site (snr.unl.edu/information/GroundwaterMaps.asp).
A multi-year drought started in 2000 and subsided last year for all but western Nebraska, according to Jess.
Over the long term, areas of declining groundwater stand out. Box Butte, Chase, Perkins and Dundy counties show drops of more than 40 feet in some areas, comparing the earliest measurements with this year's. Along the Platte River, extending south between the Big Blue and Little Blue rivers, and north to the South Loup River, declines are generally less than 20 feet.
Burbach notes that western Nebraska has not benefited in the short term from the above-normal rains that have helped the rest of the state. Also, since the 1980s and 1990s, two of the wettest decades on record, groundwater levels in eastern Nebraska were mostly back to where they were when measurements first were recorded.
Some of the areas on the map showing the most dramatic long-term increases in groundwater levels reflect surface water diversions, either canals or irrigation, that have increased groundwater recharge, Burbach and Jess say. Other areas reflect a positive balance between recharge and use.