Now anyone can easily explore the decline in local groundwater levels that has deflated the earth beneath the Houston area, at places plunging it into Galveston Bay.

The U.S. Geological Survey on Wednesday debuted a web portal displaying 40 years worth of Houston-area data on subsidence, or sinkage of the ground, which has become a major factor guiding the development of Houston in recent decades.

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The data, covering the years 1977 to 2016, shows the substantial recovery of groundwater levels since governmental action was taken to limit their decline. Areas near the Houston Ship Channel have seen the aquifer climb to about 100 feet below sea level in 2016, up from nearly 300 feet below in 1977.

The web portal also charts soil compaction. The most drastic example, around Interstate 10 near Jersey Village, has logged 3.5 feet of compaction since 1977, causing the ground to sink.

"The water-level and compaction data provided by the USGS is absolutely critical for water managers and planners to make informed resource management decisions throughout the region," said Mike Turco, general manager of the Harris Galveston and Fort Bend subsidence districts.

SUBSIDENCE: For years, the Houston area has been losing ground

Each year, USGS measures groundwater levels in more than 700 wells in the 11-county Houston area. That data is used to target projects and initiatives that for decades have helped the region make tremendous reductions in daily groundwater pumpage, or groundwater withdrawals.

Now that data is publicly accessible.

"This is the first time that groundwater and subsidence data have been put together to illustrate the story of what is happening to our land and water resources in the region," said Sachin Shah, USGS chief of Gulf Coast hydrologic studies and research. "The ability to explore, visualize and compare how groundwater levels are changing over time in an easily accessible and uniform format is a tool that we hope will effectively communicate this information to area cooperators, stakeholders and the public."