USGS - science for a changing world

Water Science for Maryland, Delaware and the District of Columbia

Home Water Data April 2017 Water Conditions Summary

USGS Logo

April 2017 Water Conditions Summary

At sites used to monitor the response of water resources to changes in weather conditions in Maryland, Delaware, and the District of Columbia in April 2017, 39 percent of groundwater levels and 73 percent of monthly mean streamflows were in the normal range. Groundwater levels were below normal in 57 percent of the observation wells. The groundwater level at an observation well in Montgomery County, Maryland was at a record monthly low for the fourth consecutive month. Since March, groundwater levels decreased at 9 wells and increased at 19 wells. Monthly mean streamflows decreased at 12 streamgages and increased at 21 streamgages in April.

In April, groundwater levels at 11 of 28 USGS observation wells were in the normal range (25th-75th percentiles). Groundwater levels were below normal at 16 wells, with 10 wells below the 10th percentile, and one of these wells was at a record April low. One well had an above normal groundwater level.

Monthly mean streamflows were in the normal range at 24 of 33 USGS streamgages. Streamflow was between the 10th and 24th percentiles at 7 streamgages, and below the 10th percentile at 1 streamgage. Freshwater flows to the Chesapeake Bay were in the normal range. Hydrologic and weather data have not been reviewed, and are therefore provisional and subject to revision.

Freshwater flows to the Chesapeake Bay were in the normal range. Hydrologic and weather data have not been reviewed, and are therefore provisional and subject to revision.

Graph showing percentiles for monthly water conditions

*A percentile is a value on a scale from 0 to 100 that indicates the percent of a distribution that is equal to or below it. A percentile between 25 and 75 is considered normal. For example, a groundwater level in the 90th percentile is equal to or greater than 90 percent of the values recorded for that month.

To view more detailed information about Monthly Water Conditions in Maryland, Delaware, and the District of Columbia, use the navigation menu on the left.

PDF Icon Click Here for the Printable PDF of the
Current
Monthly Water Conditions report.


Why is it important for the USGS to collect and analyze water resources data?

USGS water data are valuable to the public, researchers, water managers, planners, and agricultural users, especially during extreme conditions like floods and droughts. The USGS is known for its consistent measurement techniques and the most extensive set of historical groundwater and streamflow data available to the public. Since these long-term data were collected during wet and dry periods, they can be used to assess how water resources respond to changes in temperature and precipitation, and to evaluate how current data compare to the historical data. The uniformity of the dataset enables multi-state comparisons and other comparative statistical analyses that better inform policy makers of possible water-resources conditions they might encounter in the future.


The sites used in this water summary were carefully selected to include long-term datasets, and show the response of streamflow and groundwater levelsto weather conditions, rather than the effects of human influences. Of the USGS sites presented in this summary, 13 wells and 29 streamgages have more than 50 years of data. The current streamflow and groundwater data are ranked in comparison to the historical record and summarized. In addition to groundwater and streamflow data, this summary includes precipitation and temperature data, reservoir levels, and freshwater streamflow to the Chesapeake Bay to give a more complete picture of the region’s water resources.

 


Accessibility FOIA Privacy Policies and Notices

Take Pride in America logo USA.gov logo U.S. Department of the Interior | U.S. Geological Survey
URL: https://md.water.usgs.gov/waterdata/index.html
Page Contact Information: webmaster@md.water.usgs.gov