In order to monitor drought conditions across the State, Maryland Department of the Environment performs monthly evaluations of hydrologic indicators. The indicators—precipitation, stream flow, groundwater levels and reservoir storage—are used in conjunction with the condition of water supplies, status of utilities, temperature, season of year and other relevant factors. This method was endorsed by the Statewide Water Conservation/Drought Advisory Committee to measure the impact of a drought on a regional basis throughout the State.
Drought conditions are evaluated on a regional basis. Precipitation, however, is also reviewed statewide and by county. The task force plan allows for staged response to drought, with conditions being in the "Normal," "Watch," "Warning," or "Emergency." In order for a region to be placed in the "Watch," "Warning," or "Emergency" stage, two or more indicators must be in that category or a higher level. More information about what a drought watch and a drought warning entail can be found
here.
Click here to see drought indicators for November 30, 2023.
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Click here to see drought indicators for July 9, 2023.
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Click here to see drought indicators for April 30, 2023.
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Click here to see drought indicators for February 28, 2023.
Click here to see drought indicators for January 31, 2023.
Click here to see drought indicators for December 31, 2022.
Click here to see drought indicators for November 30, 2022.
Click here to see drought indicators for October 31, 2022.
Click here to see drought indicators for September 30, 2022.
Click here to see drought indicators for August 31, 2022.
Click here to see drought indicators for July 31, 2022.
Click here to see drought indicators for June 30, 2022.
Click here to see drought indicators for May 31, 2022.
Click here to see drought indicators for April 30, 2022.
Click here to see drought indicators for March 31, 2022.
Click here to see drought indicators for February 28, 2022.
Click on column headers to see more information about each indicator
[2] Only two of four wells were available as of 2021-Feb-18
[1] Only one of the four Western Maryland wells had December 2020 measurements available when evaluated on 2021-Jan-13
[1] Data from the western reservoirs is not available as of 2020-Oct-07, but their status is presumed to be normal based on previous status.
[1] - The WSSC Patuxent reservoirs have less then 120 days of water in storage. This is as a result of the drawdown of Triadelphia as part of the Brighton Dam's rehabilitation project. This project was substantially completed on December 17, 2019
[1] - The WSSC Patuxent reservoirs have less then 120 days of water in storage. This is as a result of Brighton Dam's rehabilitation project.
[1] - The WSSC Patuxent reservoirs have less then 120 days of water in storage. This is as a result of Brighton Dam's rehabilitation project.
[1] - The WSSC Patuxent reservoirs have less then 120 days of water in storage. This is as a result of Brighton Dam's rehabilitation project.
[1] - The WSSC Patuxent reservoirs have less then 120 days of water in storage. This is as a result of Brighton Dam's rehabilitation project.
[2] - Data for the Western Maryland Reservoirs has not been received as of Oct 3, 2019, but, given previous storage values, they can be assumed to be Normal
[1] - The WSSC Patuxent reservoirs have less then 120 days of water in storage. This is as a result of Brighton Dam's rehabilitation project.
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[1] - The WSSC Patuxent reservoirs have less then 120 days of water in storage. This is as a result of Brighton Dam's rehabilitation project.
[1] - The WSSC Patuxent reservoirs have less then 120 days of water in storage. This is as a result of Brighton Dam's rehabilitation project.
[1] - The WSSC Patuxent reservoirs have less then 120 days of water in storage. This is as a result of Brighton Dam's rehabilitation project. Data from Cumberland and Frostburg was not available as of 2019-Jun-19.
[1] - The WSSC Patuxent reservoirs have less then 120 days of water in storage. This is as a result of Brighton Dam's rehabilitation project. Baltimore City reservior data is unavailable as of 2019-May-09, therefore this indicator status can not be accurately determined.
[1] - The WSSC Patuxent reservoirs have less then 135 days of water in storage. This is as a result of Brighton Dam's rehabilitation project. Baltimore City reservior data is unavailable as of 2019-Apr-22, therefore this indicator status can not be accurately determined.
Summary of Hydrologic Indicators for Febuary 28 2019 |
| Region | Rainfall | Stream Flow | Groundwater | Reservoirs | Overall Status |
| Western | Normal | Normal | Normal | Normal | Normal |
| Central | Normal | Normal | Normal | Unknown[1] | Normal |
| Eastern | Normal | Normal | Normal | N/A | Normal |
| Southern | Normal | N/A | Normal | N/A | Normal |
[1] - The WSSC Patuxent reservoirs have less then 135 days of water in storage. This is as a result of Brighton Dam's rehabilitation project. Baltimore City reservior data is unavailable as of 2019-Mar-19, therefore this indicator status can not be accurately determined.
Normal[1] - This indicator status is based on the Baltimore City reservoirs only. The WSSC Patuxent reservoirs are not included in this assessment since Brighton Dam is being rehibilitated.
Normal[1] - This indicator status is based on the Baltimore City reservoirs only. The WSSC Patuxent reservoirs are not included in this assessment since Brighton Dam is being rehibilitated.
Unknown[2] - Because of the partical US Government shutdown, field measurements for the Central and the Eastern Regions were not available. Therefore, the well status could not be assessed for the Central Region and was based on two real time wells in the Eastern Region.
Normal[1] - .This indicator status is based on the Baltimore City reservoirs only. The WSSC Patuxent reservoirs are not included in this assessment since Brighton Dam is being rehibilitated.
Normal[1] - .This indicator status is based on the Baltimore City reservoirs only. The WSSC Patuxent reservoirs are not included in this assessment since Brighton Dam is being rehibilitated.
Normal[1] - .This indicator status is based on the Baltimore City reservoirs only. The WSSC Patuxent reservoirs are not included in this assessment since Brighton Dam is being rehibilitated.
Normal[1] - .This indicator status is based on the Baltimore City reservoirs only. The WSSC Patuxent reservoirs are not included in this assessment since Brighton Dam is being rehibilitated.
Normal[1] - .This indicator status is based on the Baltimore City reservoirs only. The WSSC Patuxent reservoirs are not included in this assessment since Brighton Dam is being rehibilitated.
Normal[1] - .This indicator status is based on the Baltimore City reservoirs only. The WSSC Patuxent reservoirs are not included in this assessment since Brighton Dam is being rehibilitated.
Normal[1] - .This indicator status is based on the Baltimore City reservoirs only. The WSSC Patuxent reservoirs are not included in this assessment since Brighton Dam is being rehibilitated.
Normal[1] - .This indicator status is based on the Baltimore City reservoirs only. The WSSC Patuxent reservoirs are not included in this assessment since Brighton Dam is being rehibilitated.
Normal[1] - .The WSSC Patuxent reservoirs have less than 120 days of water in storage. This is as a result of Brighton Dam's rehibilitation project. Therefore, this indicator status is based on the Baltimore City reservoirs only.
Normal[1] - .The WSSC Patuxent reservoirs have less than 90 days of water in storage. This is as a result of Brighton Dam's rehibilitation project. Therefore, this indicator status is based on the Baltimore City reservoirs only.
Normal[1] - .The WSSC Patuxent reservoirs have less than 90 days of water in storage. This is as a result of Brighton Dam's rehibilitation project. Therefore, this indicator status is based on the Baltimore City reservoirs only.
Watch[2] - The status is considered as tentative and subject to chagne as missing information is estimated by USGS, since not all the data points were available at the time of the asssessment.
Normal[1] - The WSSC Patuxent reservoirs have less then 90 days of water in storage as of the end of December, but this is in part because Triadelphia has been drawn down for a two-year project reabilitate Brighton Dam. Therefore, this indicator status is based on the Baltimore City reservoirs only.
Watch[2] Because of the large number of missing daily streamflow values at this time (2018-Jan-10), this status must be regarded as tentative and subject to chage as missing information is estimated by USGS.
Normal[1] - The WSSC Patuxent reservoirs have less then 90 days of water in storage as of the end of November, but this is in part because Triadelphia has been drawn down for a two-year project reabilitate Brighton Dam. Therefore, this indicator status is based on the Baltimore City reservoirs only.
[1] Status held at Warning until the end-of-month evaluation.
[1] Data not received for the end of March 2017
[1] Not updated from the end of March 2017
[1] Data not received for the end of March 2017
[1] - Because of the drought status of the Central and Eastern regions when last evaluated, these regions are being evaluated biweekly.
[2] - Although two indicators are in Emergency, we are not increasing the drought status to Emergency at this time since there is no water supply in the region reporting water shortage.
[3] - The regional remains in watch pending re-evaluation at the end of the month.
Summary of Hydrologic Indicators for January 16 2017 |
| Region |
Rainfall |
Stream Flow |
Groundwater | Reservoirs |
Overall Status |
| Western | Normal | Normal | Normal | Normal | Normal |
| Central | Warning | Watch | Watch | Normal | Watch |
| Eastern | Normal | Normal | Normal | N/A | Normal |
| Southern | Watch | N/A | Normal | N/A | Normal |
Normal[1] - Although rainfall for the first two months of Water Year 2017 was 63% of normal for the Western region, a minimum of three months is needed to evaluate rainfall deficit. The normal status is based on the twelve months ending 2016-Nov-30
Normal[2] - Although rainfall for the first two months of Water Year 2017 was 46% of normal for the Central region, a minimum of three months is needed to evaluate rainfall deficit. The normal status is based on the twelve months ending 2016-Nov-30
Normal[2] - Although rainfall for the first two months of Water Year 2017 was 49% of normal for the Southern region, a minimum of three months is needed to evaluate rainfall deficit. The normal status is based on the twelve months ending 2016-Nov-30
In order to monitor drought conditions across the State, Maryland Department of the Environment performs and monthly evaluations of hydrologic indicators. These indicators are precipitation, stream flow, ground water levels and reservoir storage. These indicators are used in conjunction with the condition of water supplies, status of utilities, temperature, season of year and other relevant factors. This method was endorsed by the Water Conservation/Drought Task Force Committee to measure the impact of a drought on a regional basis throughout the State.
Drought conditions are evaluated on a regional basis. Precipitation, however, is also reviewed statewide and by county. The task force plan allows for staged response to drought, with conditions being in the "Normal," "Watch," "Warning," or "Emergency." In order for a region to be placed in the "Watch," "Warning," or "Emergency" stage, two or more indicators must be in that category or a higher level.
Previous Data and Information
Related Topics
For More Information
Please contact the Water Supply Program at
WATER.SUPPLY@maryland.gov or 410-537-3702
