USGS - science for a changing world

Water Science for Maryland, Delaware and the District of Columbia


USGS Water Data

Image of a stream

USGS water data is valuable to the public, researchers, water managers, planners, and agricultural users, especially during floods and droughts. These data can be used to assess how water resources respond to changes in climate. Scientists at the USGS have measured streamflow and groundwater levels in wells to assess water resources for over 125 years.

In addition to providing the most extensive set of historical streamflow and groundwater data available to the public, the USGS collects water data and quality-assures the data by employing standardized techniques across the country. The uniformity of the dataset allows for multi-state comparisons and other comparative statistical analyses that better inform policy makers of the possible water resource conditions they might encounter in the future.

The sites used in this water summary were carefully selected to show the response of streamflow and groundwater levels to precipitation. Ideally, these sites will show minimal effects from human influences. The streamflow and groundwater data are ranked in comparison to the historical record and summarized. Precipitation and reservoir data are also presented to give a more complete picture of the regionís water resources.

Monthly Water Conditions Report

Small image of a water pump

These reports assess monthly streamflow and groundwater levels at sites monitored by the USGS throughout the MD-DE-DC region. The resulting data are used to evaluate the region's response to climatic conditions.

>> USGS Maryland-Delaware-DC Monthly Water Conditions Summary for December 2014
>> Archive of Water Conditions Reports

Monthly Groundwater Level

Click here to go to the Groundwater Main Page for more information.

Current Groundwater information maps are listed by county, categorized by water table, or confined aquifer, with 5 year information. This information is based on monthly readings from selected wells in the MD-DE-DC Water Science Center.

Water-Table Wells
View water table well data by county for Maryland and Delaware, or by jurisdiction for Baltimore City and D.C.

Real-Time Groundwater

View Real-Time Groundwater Wells By Region:

Map of MD

Map of DE

Map of DC
District of Columbia

The Real-Time Groundwater Level Network contains water level data that is typically recorded every 15-60 minutes, and transmitted to USGS offices every few hours. Transmissions may be more frequent during critical events. * Note: This is provisional data and is subject to revision.

Click here to view the Real-Time Groundwater Network
Click here to view the region-wide Groundwater Real-Time Table

Monthly Streamflow Levels

Current streamflow information maps are listed by county with 5 year information. This information is based on readings from streamflow gages monitored by the MD-DE-DC Water Science Center.

Click here to view detailed streamflow information by site location.


Satellite Image of Chesapeake Bay

Click here to view a summary of the Chesapeake Bay monthly streamflow conditions.

Real-Time Surface Water

View Real-Time Surface Water Wells By Region:

Map of MD  Maryland | Map of DE  Delaware | Map of DC  District of Columbia

The term surface water includes the rivers, streams, ponds, and lakes of Maryland, Delaware, and D.C. Data about these resources are available in either real-time or monthly.

Select MD, DE, or DC to view real-time surface water information by region. The resulting map will depict streamflow conditions as a percentile, which is computed from the period of record for the current day of the year. Only stations with at least 30 years of record are used. After selecting a map, hold down the Shift key and click on Reload or Refresh to make sure you are viewing the most recent image or table.

Use the following links to view the data in a table format:

Maryland | Delaware | District of Columbia

Tide Gage Sites

Tide Gage Sites

Tide gage sites in MD-DE-DC

Select a location on the map to view the tidal data for the corresponding site.

Additional Tide and Surge Links:

Indian River Bay Inlet Rehoboth Bay Potomac River Christina River At Newport, DE Murderkill River at Frederica, DE Anacostia River Little Assawoman Bay Jefferson Creek Murderkill River at Bowers, DE Indian River Nanticoke River Christina River At Wilmington, DE

Freshwater Use and Withdrawals

Young child drinking fresh water from a glass

During 2000, about 1,500 million gallons per day (Mgal/d) of freshwater was withdrawn from surface-water and groundwater sources in Maryland for a variety of uses including:

- public-supply distribution (PS)
- commercial (CO)
- self-supplied domestic (DO)
- industrial (IN)
- mining (MI)
- thermoelectric power generation (TE)
- livestock watering (LV)
- aquaculture (AQ)
- irrigation(IR).


Click here for more information.

Other Water Information

Maps and animations of monthly streamflows >> National Water Conditions

Surface-Water Data Retrieval(Daily streamflow and peak flows):
River Input Monitoring (Fall Line) Stations:
     >> Maryland - Susquehanna, Choptank, Patuxent, Potomac
     >> Virginia - Rappahannock, James, Pomunkey, Mattaponi, Appomattox

Surface Water Site Inventory

Active continuous streamflow sites (as of 2005)

Discontinued continuous streamflow sites (as of 2005)

Water Tools

Convert values from cfs (cubic feet per second) using the >> CFS Calculator (Link opens a new window)

Real-Time Streamflow Regional Quick-Navigation

This feature allows the user to navigate through each real-time station in numerical sequence (Maryland and Delaware)

Frequently Asked Questions
Water Watch

Related Information
For an explanation of stream gaging, see:

Weather and Climate Information

Radar Image

Climatological data, weather forecasts, and live satellite imagery for the Maryland, Delaware, and the District of Columbia region from a variety of public and private resources.

Click here for Weather and Climate Information

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Page Last Modified: Friday, October 24, 2014