2019 Annual WMA Drought Exercise, November 20-21, 2019


Morning Potomac flow and demand update (Thursday 2019-11-21)

This is Day 2 of the annual Washington metropolitan area (WMA) drought exercise. The exercise scenario appears below. During the exercise, WMA water suppliers are sending data on withdrawals and reservoir levels twice daily, and ICPRB CO-OP staff are communicating via phone with supplier operations staff regarding requested operational changes.

EXERCISE SCENARIO

The day is Thursday, August 27, 2020 and the basin is in moderate drought. The region experienced a “flash drought” during September of last year, and precipitation continued to be low throughout the past fall and winter. CO-OP began daily drought monitoring in mid-June, when Potomac River flow at Point of Rocks, Maryland fell below 2000 cubic feet per second. Enhanced drought monitoring began on Friday, July 24, when daily flow in the Potomac River above the Washington metropolitan area intakes, less the amount required for the flow-by over Little Falls Dam, fell to a level less than twice the total daily withdrawals. Releases from upstream reservoirs, Jennings Randolph and Little Seneca, began in early August. Combined upstream storage is currently 11.4 billion gallons (BG) (simulated), or 67% of combined capacity. The drought stage, per the MWCOG regional plan, is “Watch”.

This morning, simulated hourly flow at Little Falls has dipped below 100 MGD. We believe this to be due to a temporary elevation in the previous night's withdrawals on the Potomac. But as a precautionary measure, a WSSC load shift to the Patuxent is being implemented to ensure that average daily flow is above 100 MGD at Little Falls. We have also increased the Little Seneca release to 100 MGD based on today's 1-day flow forecast for Little Falls. There is a high probability of substantial rain in the next three days, which should alleviate dry conditions.

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ACTUAL CONDITIONS REPORTED BELOW

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Recent basin-wide average precipitation (above Little Falls):

(based on CO-OP's Low Flow Forecast System analysis of Middle Atlantic River Forecast Center (MARFC) gridded multisensor precipitation estimates)

Yesterday's area-weighted average basin precip: 0.00 (inches)

Past 3-day cumulative area-weighted average basin precip: 0.01 (inches)

Past 7-day cumulative area-weighted average basin precip: 0.01 (inches)

Daily Flows:

Little Falls gage flow 2019-11-20: 1790 MGD (2770 cfs)

Little Falls gage flow 2019-11-21: 1680 MGD (est., based on recently available real time data) (2600 cfs)

Note: Gage flow at Little Falls is measured after water supply withdrawals.

Point of Rocks flow 2019-11-20: 1551 MGD (2400 cfs)

Point of Rocks flow 2019-11-21: 1428 MGD (est., based on recently available real time data) (2210 cfs)

Yesterday's Net Potomac withdrawal (2019-11-20):

FW Corbalis withdrawal (Potomac): 86 MGD

WSSC Potomac withdrawal: 110 MGD

Aqueduct withdrawal: 110 MGD

Loudoun withdrawal: 10 MGD

Total Potomac withdrawal: 316 MGD

Yesterday's Patuxent, Occoquan, and Net Total System Withdrawal (2019-11-20):

FW Occoquan withdrawal: 65 MGD

WSSC Patuxent withdrawal: 39 MGD

Total system withdrawal: 410 MGD

Loudoun Water Broad Run discharge:

Yesterday's (2019-11-20): 5 MGD

Today's (2019-11-21): 5 MGD

Tomorrow's (2019-11-22): 5 MGD

Today's estimated production* (2019-11-21):

FW estimated production: 160 MGD

WSSC estimated production: 142 MGD

Aqueduct estimated production: 137 MGD

Total estimated production: 439 MGD

*Based on CO-OP daily demand forecasting models

Tomorrow's estimated production* (2019-11-22):

FW estimated production: 159 MGD

WSSC estimated production: 143 MGD

Aqueduct estimated production: 136 MGD

Total estimated production: 438 MGD

*Based on CO-OP daily demand forecasting models

Reservoirs - Usable storage (2019-11-21 A.M., BG):

Facility, %Full, Current, Capacity*

WSSC’s Patuxent reservoirs, 46%, 4.67, 10.2

Fairfax Water’s Occoquan reservoir, 95%, 8.05, 8.5

Little Seneca Reservoir, 99%, 3.87, 3.9

Jennings Randolph Total Reservoir, 64%,18.9, 29.4

Jennings Randolph water supply**, 100%, 13.1, 13.1

Jennings Randolph water quality**, 36%, 5.8, 16.3

Savage Reservoir, 41%, 2.6, 6.3

*Storage and capacities for Occoquan, Patuxent and Little Seneca reservoirs are provided by Washington metropolitan area water utilities, and based on best available information. Storage and capacities for Jennings Randolph and Savage reservoirs are based on observed water levels and available US ACE water level/storage tables from 1998. ICPRB estimates that sedimentation has resulted in a loss of total available storage in Jennings Randolph Reservoir of 1.6 BG in recent years, and this loss is not reflected in the numbers above.

** ICPRB's initial estimate. Final accounting of Jennings Randolph water supply versus water quality storage will be provided at a later date by the US ACE.

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SIMULATED CONDITIONS AND DROUGHT OPERATIONS APPEAR BELOW

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Recommended operations (simulated) for today (2019-11-21 A.M.):

Fairfax Water:

Occoquan/Griffith - maintain maximum production at plant (simulated)

Potomac/Corbalis - per operational preference, but keeping Potomac withdrawal rate as steady as possible

WSSC:

Patuxent - immediate load shift to maximum 65 MGD production (simulated, assuming no maintenance constraints; due to dam maintenance, 40 MGD is current actual Patuxent plant max)

Potomac - per operational preference, but keeping Potomac withdrawal rate as steady as possible

Seneca (release date, time, amount in MGD):

Immediate increase release from Little Seneca Reservoir to 100 MGD (simulated)

Aqueduct:

No change in operations requested. Continue making entire withdrawal from Little Falls (simulated)

North Branch Reservoirs A.M. Summary:

Jennings Randolph water supply release (simulated): Luke target of 255 cfs (165 MGD)

Afternoon Potomac flow and demand update (Wednesday 2019-11-20)

NOTE: In our twice daily reports for the 2019 exercise we are reporting ACTUAL basin flows and system withdrawals, and SIMULATED recommended operations  

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ACTUAL CONDITIONS REPORTED BELOW

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Daily Flows:

Little Falls gage flow 2019-11-19: 1790 MGD (2770 cfs)

Little Falls gage flow 2019-11-20: 1745 MGD (est., based on recently available real time data) (2700 cfs)

Note: Gage flow at Little Falls is measured after water supply withdrawals.

Point of Rocks flow 2019-11-19: 1616 MGD (2500 cfs)

Point of Rocks flow 2019-11-20: 1487 MGD (est., based on recently available real time data) (2300 cfs)

Tomorrow's estimated production* (2019-11-21):

FW estimated production:155 MGD

WSSC estimated production:141 MGD

Aqueduct estimated production:135 MGD

Total estimated production:431 MGD

*Based on CO-OP daily demand forecasting models

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SIMULATED CONDITIONS AND DROUGHT OPERATIONS APPEAR BELOW

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Recommended operations for today (2019-11-20 P.M.):

No (SIMULATED) operational changes recommended for this afternoon.


Morning Potomac flow and demand update (Wednesday 2019-11-20)

This is Day 1 of the annual Washington metropolitan area (WMA) drought exercise, which will be conducted on Wednesday, Nov 20 and Thursday, Nov 21. The exercise scenario appears below. During the exercise, WMA water suppliers are sending data on withdrawals and reservoir levels twice daily, and ICPRB CO-OP staff are communicating via phone with supplier operations staff regarding requested operational changes.

EXERCISE SCENARIO

The day is Wednesday, August 26, 2020 and the basin is in moderate drought. The region experienced a “flash drought” during September of last year, and precipitation continued to be low throughout the past fall and winter. CO-OP began daily drought monitoring in mid-June, when Potomac River flow at Point of Rocks, Maryland fell below 2000 cubic feet per second. Enhanced drought monitoring began on Friday, July 24, when daily flow in the Potomac River above the Washington metropolitan area intakes, less the amount required for the flow-by over Little Falls Dam, fell to a level less than twice the total daily withdrawals. Releases from upstream reservoirs, Jennings Randolph and Little Seneca, began in early August. Combined upstream storage is currently 11.5 BG (simulated), or 68% of combined capacity. The drought stage, per the MWCOG regional plan, is “Watch”.

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ACTUAL CONDITIONS REPORTED BELOW

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Recent basin-wide average precipitation (above Little Falls):

(based on CO-OP's Low Flow Forecast System analysis of Middle Atlantic River Forecast Center (MARFC) gridded multisensor precipitation estimates)

Yesterday's area-weighted average basin precip: 0.01 (inches)

Past 3-day cumulative area-weighted average basin precip: 0.01 (inches)

Past 7-day cumulative area-weighted average basin precip: 0.01 (inches)

Daily Flows:

Little Falls gage flow 2019-11-19: 1790 MGD (2770 cfs)

Little Falls gage flow 2019-11-20: 1745 MGD (est., based on recently available real time data) (2700 cfs)

Note: Gage flow at Little Falls is measured after water supply withdrawals.

Point of Rocks flow 2019-11-19: 1616 MGD (2500 cfs)

Point of Rocks flow 2019-11-20: 1461 MGD (est., based on recently available real time data) (2260 cfs)

Yesterday's Net Potomac withdrawal (2019-11-19):

FW Corbalis withdrawal (Potomac): 91 MGD

WSSC Potomac withdrawal: 114 MGD

Aqueduct withdrawal: 112 MGD

Loudoun withdrawal: 10 MGD

Total Potomac withdrawal: 327 MGD

Yesterday's Patuxent, Occoquan, and Net Total System Withdrawal (2019-11-19):

FW Occoquan withdrawal: 67 MGD

WSSC Patuxent withdrawal: 39 MGD

Total system withdrawal: 422 MGD

Loudoun Water Broad Run discharge:

Yesterday's (2019-11-19): 5 MGD

Today's (2019-11-20): 5 MGD

Tomorrow's (2019-11-21): 5 MGD

Today's estimated production* (2019-11-20):

FW estimated production: 159 MGD

WSSC estimated production: 141 MGD

Aqueduct estimated production: 135 MGD

Total estimated production: 435 MGD

*Based on CO-OP daily demand forecasting models

Tomorrow's estimated production* (2019-11-21):

FW estimated production: 155 MGD

WSSC estimated production: 141 MGD

Aqueduct estimated production: 135 MGD

Total estimated production: 431 MGD

*Based on CO-OP daily demand forecasting models

Reservoirs - Usable storage (actual on 2019-11-20 A.M., BG):

Facility,                                                                 %Full,             Current, Capacity*

WSSC’s Patuxent reservoirs,                                 46%,              4.69,             10.2

Fairfax Water’s Occoquan reservoir,                      96%,              8.12,               8.5

Little Seneca Reservoir,                                         99%,              3.88,               3.9

Jennings Randolph Total Reservoir,                       65%,             19.0,             29.4

Jennings Randolph water supply**,                      100%,             13.1,             13.1

Jennings Randolph water quality**,                        36%,               5.9,             16.3

Savage Reservoir,                                                  41%,               2.6,               6.3

*Storage and capacities for Occoquan, Patuxent and Little Seneca reservoirs are provided by Washington metropolitan area water utilities, and based on best available information. Storage and capacities for Jennings Randolph and Savage reservoirs are based on observed water levels and available US ACE water level/storage tables from 1998. ICPRB estimates that sedimentation has resulted in a loss of total available storage in Jennings Randolph Reservoir of 1.6 BG in recent years, and this loss is not reflected in the numbers above.

** ICPRB's initial estimate. Final accounting of Jennings Randolph water supply versus water quality storage will be provided at a later date by the US ACE.

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SIMULATED CONDITIONS AND DROUGHT OPERATIONS APPEAR BELOW

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Recommended operations (simulated) for today (2019-11-20 A.M.):

Fairfax Water:

Occoquan/Griffith - increase production (simulated) by 30 MGD from yesterday's rate

Potomac/Corbalis - per operational preference, but keeping Potomac withdrawal rate as steady as possible

WSSC:

Keep Potomac withdrawal rate (simulated) as steady as possible.

Seneca (release date, time, amount in MGD):

Initiate release from Little Seneca Reservoir of 12 MGD (simulated).

Aqueduct:

No change in operations requested. Continue making entire withdrawal from Little Falls (simulated).

North Branch Reservoirs A.M. Summary:

Jennings Randolph water supply release (simulated): Luke target of 223 cfs (144 MGD)

2019 DROUGHT EXERCISE REPORTS END HERE


Daily Monitoring was initiated on 9/23/2019 and discontinued on 10/23/2019.

Monitoring reports


Daily Potomac flow and demand update (Wednesday 2019-10-23)

River flow at Point of Rocks has been above our drought monitoring trigger of 2000 cfs for the past two days, and the Middle Atlantic River Forecast Center's streamflow forecasts indicate that flows will remain above this level for the next week. Therefore, daily monitoring will be discontinued until further notice. Thank you all for your contributions to the monitoring effort!

Recent basin-wide average precipitation (above Little Falls):

(based on CO-OP's Low Flow Forecast System analysis of Middle Atlantic River Forecast Center (MARFC) gridded multisensor precipitation estimates)

Yesterday's area-weighted average basin precip: 0.57491 (inches)

Past 3-day cumulative area-weighted average basin precip: 1.01276 (inches)

Past 7-day cumulative area-weighted average basin precip: 1.6669 (inches)

Daily Flows:

Little Falls gage flow 2019-10-22: 1648 MGD (2550 cfs)

Little Falls gage flow 2019-10-23: 1842 MGD (est., based on recently available real time data) (2850 cfs)

Note: Gage flow at Little Falls is measured after water supply withdrawals.

Point of Rocks flow 2019-10-22: 1415 MGD (2190 cfs)

Point of Rocks flow 2019-10-23: 1506 MGD (est., based on recently available real time data) (2330 cfs)

Yesterday's Net Potomac withdrawal (2019-10-22):

FW Corbalis withdrawal (Potomac): 78 MGD

WSSC Potomac withdrawal: 153 MGD

Aqueduct withdrawal: 129 MGD

Loudoun withdrawal: 10 MGD

Total Potomac withdrawal: 370 MGD


Daily Potomac flow and demand update (Tuesday 2019-10-22)

No rain fell in the basin over the past 24 hours according to the Middle Atlantic River Forecast Center.  Over the next 7 days, between 1 and 1.75 inches of rain are expected in the basin.

Flows have been fluctuating around 2000 cfs, the threshold for daily monitoring.  Daily monitoring will be continued until flows are consistently above the 2000 cfs threshold.

Recent basin-wide average precipitation (above Little Falls):

(based on CO-OP's Low Flow Forecast System analysis of Middle Atlantic River Forecast Center (MARFC) gridded multisensor precipitation estimates)

Yesterday's area-weighted average basin precip: 0 (inches)

Past 3-day cumulative area-weighted average basin precip: 0.44 (inches)

Past 7-day cumulative area-weighted average basin precip: 1.09 (inches)

Daily Flows:

Little Falls gage flow 2019-10-21: 1900 MGD (2940 cfs)

Little Falls gage flow 2019-10-22: 1583 MGD (est., based on recently available real time data) (2450 cfs)

Note: Gage flow at Little Falls is measured after water supply withdrawals.

Point of Rocks flow 2019-10-21: 1390 MGD (2150 cfs)

Point of Rocks flow 2019-10-22: 1415 MGD (est., based on recently available real time data) (2190 cfs)

Yesterday's Net Potomac withdrawal (2019-10-21):

FW Corbalis withdrawal (Potomac): 81 MGD

WSSC Potomac withdrawal: 166 MGD

Aqueduct withdrawal: 137 MGD

Loudoun withdrawal: 10 MGD

Total Potomac withdrawal: 394 MGD


Daily Potomac flow and demand update (Monday 2019-10-21)

On average, the basin received less than half an inch of rainfall yesterday, with rainfall totals increasing from west to east.  Far western areas of the basin received trace amounts of rain while rainfall totals exceeded 1.5 inches in parts of the DC metro area.  Between 0.5 and 1.5 inches of additional rainfall is expected over the next 7 days.  

Recent basin-wide average precipitation (above Little Falls):

(based on CO-OP's Low Flow Forecast System analysis of Middle Atlantic River Forecast Center (MARFC) gridded multisensor precipitation estimates)

Yesterday's area-weighted average basin precip: 0.44 (inches)

Past 3-day cumulative area-weighted average basin precip: 0.44 (inches)

Past 7-day cumulative area-weighted average basin precip: 1.09 (inches)

Daily Flows:

Little Falls gage flow 2019-10-20: 1829 MGD (2830 cfs)

Little Falls gage flow 2019-10-21: 2049 MGD (est., based on recently available real time data) (3170 cfs)

Note: Gage flow at Little Falls is measured after water supply withdrawals.

Point of Rocks flow 2019-10-20: 1267 MGD (1960 cfs)

Point of Rocks flow 2019-10-21: 1415 MGD (est., based on recently available real time data) (2190 cfs)

Yesterday's Net Potomac withdrawal (2019-10-20):

FW Corbalis withdrawal (Potomac): 88 MGD

WSSC Potomac withdrawal: 168 MGD

Aqueduct withdrawal: 135 MGD

Loudoun withdrawal: 10 MGD

Total Potomac withdrawal: 401 MGD


Daily Potomac flow and demand update (Sunday 2019-10-20)

According to the Middle Atlantic River Forecast Center (MARFC), 0.01 to 0.75 inches of precipitation fell in the basin over the last 24 hours (ending at 7:00 AM Sunday). It is currently raining and MARFC forecasts that 0.75 to 2.00 inches of precipitation will fall over the next 72 hours. The National Weather Service expects 1.25 to 3.00 inches of precipitation over the next 7 days.

Flows at the USGS gage at Point of Rocks are currently above 2000 cfs, the trigger for daily monitoring. Daily monitoring will be continued at this time to confirm that flows remain above the 2000 cfs threshold for a few days given recent gage corrections.The MARFC GEFS forecasts that flows may improve this week, at which point we may revise this decision.

Recent basin-wide average precipitation (above Little Falls):

(based on CO-OP's Low Flow Forecast System analysis of Middle Atlantic River Forecast Center (MARFC) gridded multisensor precipitation estimates)

Yesterday's area-weighted average basin precip: 0 (inches)

Past 3-day cumulative area-weighted average basin precip: 0.00 (inches)

Past 7-day cumulative area-weighted average basin precip: 0.65 (inches)

Daily Flows:

Little Falls gage flow 2019-10-19: 1461 MGD (2260 cfs)

Little Falls gage flow 2019-10-20: 1396 MGD (est., based on recently available real time data) (2160 cfs)

Note: Gage flow at Little Falls is measured after water supply withdrawals.

Point of Rocks flow 2019-10-19: 1409 MGD (2180 cfs)

Point of Rocks flow 2019-10-20: 1338 MGD (est., based on recently available real time data) (2070 cfs)

Yesterday's Net Potomac withdrawal (2019-10-19):

FW Corbalis withdrawal (Potomac): 85 MGD

WSSC Potomac withdrawal: 157 MGD

Aqueduct withdrawal: 130 MGD (estimated)

Loudoun withdrawal: 10 MGD

Total Potomac withdrawal: 382 MGD


Daily Potomac flow and demand update (Saturday 2019-10-19)

According to the Middle Atlantic River Forecast Center, no rain fell in the basin over the past 24 hours.  The National Weather Service expects up to an inch of rain in the basin over the next 7 days.

Flows at the USGS gage at Point of Rocks are currently above 2000 cfs, the trigger for daily monitoring. Please note, however, that the USGS has been working on some recent issues with the stage sensor at the Point of Rocks gage. Daily monitoring will be continued at this time to confirm that flows remain above the 2000 cfs threshold for a few days given recent gage corrections.

Recent basin-wide average precipitation (above Little Falls):

(based on CO-OP's Low Flow Forecast System analysis of Middle Atlantic River Forecast Center (MARFC) gridded multisensor precipitation estimates)

Yesterday's area-weighted average basin precip: 0 (inches)

Past 3-day cumulative area-weighted average basin precip: 0.65 (inches)

Past 7-day cumulative area-weighted average basin precip: 0.67 (inches)

Daily Flows:

Little Falls gage flow 2019-10-18: 1519 MGD (2350 cfs)

Little Falls gage flow 2019-10-19: 1461 MGD (est., based on recently available real time data) (2260 cfs)

Note: Gage flow at Little Falls is measured after water supply withdrawals.

Point of Rocks flow 2019-10-18: 1293 MGD (2000 cfs)

Point of Rocks flow 2019-10-19: 1474 MGD (est., based on recently available real time data) (2280 cfs)

Yesterday's Net Potomac withdrawal (2019-10-18):

FW Corbalis withdrawal (Potomac): 98 MGD

WSSC Potomac withdrawal: 163 MGD

Aqueduct withdrawal: 144 MGD

Loudoun withdrawal: 11 MGD

Total Potomac withdrawal: 416 MGD


Daily Potomac flow and demand update (Friday 2019-10-18)

In the last 24 hours, trace amounts of precipitation fell in Washington County, Maryland. According to MARFC's precipitation departure calculations, last Wednesday's precipitation improved basin precipitation totals, which are now near normal for the month of October. Precipitation amounts between 0.5 and 0.75 are expected over the next 5 to 7 days.

Flow at the USGS gage at Point of Rocks is currently below 2000 cfs, the trigger for daily monitoring. Daily monitoring will be continued at this time. *

Recent basin-wide average precipitation (above Little Falls):

(based on CO-OP's Low Flow Forecast System analysis of Middle Atlantic River Forecast Center (MARFC) gridded multisensor precipitation estimates)

Yesterday's area-weighted average basin precip: 0.00 (inches)

Past 3-day cumulative area-weighted average basin precip: 0.65 (inches)

Past 7-day cumulative area-weighted average basin precip: 0.67 (inches)

Daily Flows:

Little Falls gage flow 2019-10-17: 1829 MGD (2830 cfs)

Little Falls gage flow 2019-10-18: 1519 MGD (est., based on recently available real time data) (2350 cfs)

Note: Gage flow at Little Falls is measured after water supply withdrawals.

Point of Rocks flow 2019-10-17: 1241 MGD (1920 cfs)

Point of Rocks flow 2019-10-18: 1267 MGD (est., based on recently available real time data) (1960 cfs)

Yesterday's Net Potomac withdrawal (2019-10-17):

FW Corbalis withdrawal (Potomac): 87 MGD

WSSC Potomac withdrawal: 163 MGD

Aqueduct withdrawal: 134 MGD

Loudoun withdrawal: 10 MGD

Total Potomac withdrawal: 394 MGD

* Note: The USGS is having some issues with the stage sensor at the site and is checking it out this morning.


​Daily Potomac flow and demand update (Thursday 2019-10-17)

According to the Middle Atlantic River Forecasting Center, between 0.25 and 1.5 inches of rain fell in the basin over the past 24 hours. This amounts to a basin-wide average precipitation of about 0.65 inches. Between 0.75 and 1.75 inches of rain is expected over the next 7 days.

Because flows at the USGS gage at Point of Rocks have not significantly risen above 2000 cfs, the trigger for daily monitoring, daily monitoring will be continued at this time. ​Increases in flows ​are expected ​to begin occurring over the next day or two​, at which point we will reassess the need for daily monitoring​.​ ​

​​Recent basin-wide average precipitation (above Little Falls):

(based on CO-OP's Low Flow Forecast System analysis of Middle Atlantic River Forecast Center (MARFC) gridded multisensor precipitation estimates)

Yesterday's area-weighted average basin precip: 0.65141 (inches)

Past 3-day cumulative area-weighted average basin precip: 0.65141 (inches)

Past 7-day cumulative area-weighted average basin precip: 0.6678 (inches)

​​Daily Flows:

Little Falls gage flow 2019-10-16: 1596 MGD (2470 cfs)

Little Falls gage flow 2019-10-17: 1945 MGD (est., based on recently available real time data) (3010 cfs)

Note: Gage flow at Little Falls is measured after water supply withdrawals.

Point of Rocks flow 2019-10-16: 1267 MGD (1960 cfs)

Point of Rocks flow 2019-10-17: 1293 MGD (est., based on recently available real time data) (2000 cfs)

​​Yesterday's Net Potomac withdrawal (2019-10-16):

FW Corbalis withdrawal (Potomac): 99 MGD

WSSC Potomac withdrawal: 166 MGD

Aqueduct withdrawal: 150 MGD

Loudoun withdrawal: 11 MGD

Total Potomac withdrawal: 426 MGD


​Daily Potomac flow and demand update (Wednesday 2019-10-16)

No significant amount of rain has fallen in the Potomac basin over the past 3 days. Around midnight last night, flow in the Potomac River at Point of Rocks temporarily dropped below CO-OP's threshold for drought monitoring of 2,000 cfs. We will reassess the need for daily monitoring after today's expected rainfall. According to Middle Atlantic River Forecast Center estimates, 1.25 to 2.5 inches is expected throughout the basin in the next 7 days. Slightly smaller amounts of 0.5 to 1.25 inches is expected in the next 5 days.

​​Recent basin-wide average precipitation (above Little Falls):

(based on CO-OP's Low Flow Forecast System analysis of Middle Atlantic River Forecast Center (MARFC) gridded multisensor precipitation estimates)

Yesterday's area-weighted average basin precip: 0 (inches)

Past 3-day cumulative area-weighted average basin precip: 0.00 (inches)

Past 7-day cumulative area-weighted average basin precip: 0.06 (inches)

​​Daily Flows:

Little Falls gage flow 2019-10-15: 1273 MGD (1970 cfs)

Little Falls gage flow 2019-10-16: 1312 MGD (est., based on recently available real time data) (2030 cfs)

Note: Gage flow at Little Falls is measured after water supply withdrawals.

Point of Rocks flow 2019-10-15: 1409 MGD (2180 cfs)

Point of Rocks flow 2019-10-16: 1325 MGD (est., based on recently available real time data) (2050 cfs)

​​

Yesterday's Net Potomac withdrawal (2019-10-15):

FW Corbalis withdrawal (Potomac): 105 MGD

WSSC Potomac withdrawal: 175 MGD

Aqueduct withdrawal: 148 MGD

Loudoun withdrawal: 10 MGD

Total Potomac withdrawal: 438 MGD


Daily Potomac flow and demand update (Tuesday 2019-10-15)

According to the Middle Atlantic River Forecasting Center, no rain fell in the basin over the past 24 hours.  Between 0.25 and 1 inch of rain is expected over the next 3 days.

Although flows at the USGS gage at Point of Rocks are currently above 2000 cfs, the trigger for daily monitoring, daily monitoring will be continued at this time.  

Recent basin-wide average precipitation (above Little Falls):

(based on CO-OP's Low Flow Forecast System analysis of Middle Atlantic River Forecast Center (MARFC) gridded multisensor precipitation estimates)

Yesterday's area-weighted average basin precip: 0 (inches)

Past 3-day cumulative area-weighted average basin precip: 0.02 (inches)

Past 7-day cumulative area-weighted average basin precip: 0.44 (inches)

Daily Flows:

Little Falls gage flow 2019-10-14: 1228 MGD (1900 cfs)

Little Falls gage flow 2019-10-15: 1280 MGD (est., based on recently available real time data) (1980 cfs)

Note: Gage flow at Little Falls is measured after water supply withdrawals.

Point of Rocks flow 2019-10-14: 1461 MGD (2260 cfs)

Point of Rocks flow 2019-10-15: 1519 MGD (est., based on recently available real time data) (2350 cfs)

Yesterday's Net Potomac withdrawal (2019-10-14):

FW Corbalis withdrawal (Potomac): 119 MGD

WSSC Potomac withdrawal: 176 MGD

Aqueduct withdrawal: 148 MGD

Loudoun withdrawal: 9 MGD

Total Potomac withdrawal: 452 MGD


Daily Potomac flow and demand update (Monday 2019-10-14)

No significant amount of rain has fallen in the Potomac basin over the past 3 days. According to Middle Atlantic River Forecast Center estimates, 1/4 to 3/4 inches is expected throughout the basin on Wednesday. Flow in the Potomac River at Point of Rocks is still elevated from last week's rainfall, and is above CO-OP's threshold for drought monitoring. We will reassess the need for daily monitoring after Wednesday's rainfall.

Recent basin-wide average precipitation (above Little Falls):

(based on CO-OP's Low Flow Forecast System analysis of Middle Atlantic River Forecast Center (MARFC) gridded multisensor precipitation estimates)

Yesterday's area-weighted average basin precip: 0.00054 (inches)

Past 3-day cumulative area-weighted average basin precip: 0.01639 (inches)

Past 7-day cumulative area-weighted average basin precip: 0.98835 (inches)

Daily Flows:

Little Falls gage flow 2019-10-13: 1286 MGD (1990 cfs)

Little Falls gage flow 2019-10-14: 1222 MGD (est., based on recently available real time data) (1890 cfs)

Note: Gage flow at Little Falls is measured after water supply withdrawals.

Point of Rocks flow 2019-10-13: 1377 MGD (2130 cfs)

Point of Rocks flow 2019-10-14: 1461 MGD (est., based on recently available real time data) (2260 cfs)

Yesterday's Net Potomac withdrawal (2019-10-13):

FW Corbalis withdrawal (Potomac): 101 MGD

WSSC Potomac withdrawal: 171 MGD

Aqueduct withdrawal: 147 MGD (estimated based on ICPRB forecast algorithm; actual value not available at this time)

Loudoun withdrawal: 10 MGD

Total Potomac withdrawal: 430 MGD


Daily Potomac flow and demand update (Sunday 2019-10-13)

Trace amounts of precipitation occurred around the outer perimeter of the basin, resulting in an average basin precipitation of 0.016 inches for yesterday. According to MARFC, the basin precipitation for the month of October is currently at 1 inch, which is about normal for this time of the month. Above the USGS gage at Point of Rocks, this precipitation has returned some of the precipitation totals to near normal or above normal for the month. However, below this USGS gage, greater than 75% below normal precipitation totals for the month remain throughout the basin. The 5-day and 7-day MARFC forecast calls for 0.5 to 0.75 inches of possible precipitation.

Although flows at the USGS gage at Point of Rocks are currently above 2000 cfs, the trigger for daily monitoring, daily monitoring will be continued at this time.

Recent basin-wide average precipitation (above Little Falls):

(based on CO-OP's Low Flow Forecast System analysis of Middle Atlantic River Forecast Center (MARFC) gridded multisensor precipitation estimates)

Yesterday's area-weighted average basin precip: 0.01585 (inches)

Past 3-day cumulative area-weighted average basin precip: 0.01585 (inches)

Past 7-day cumulative area-weighted average basin precip: 1.0971 (inches)

Daily Flows:

Little Falls gage flow 2019-10-12: 1280 MGD (1980 cfs)

Little Falls gage flow 2019-10-13: 1312 MGD (est., based on recently available real time data) (2030 cfs)

Note: Gage flow at Little Falls is measured after water supply withdrawals.

Point of Rocks flow 2019-10-12: 1409 MGD (2180 cfs)

Point of Rocks flow 2019-10-13: 1351 MGD (est., based on recently available real time data) (2090 cfs)

Yesterday's Net Potomac withdrawal (2019-10-12):

FW Corbalis withdrawal (Potomac): 101 MGD

WSSC Potomac withdrawal: 174 MGD

Aqueduct withdrawal: 142 MGD

Loudoun withdrawal: 10 MGD

Total Potomac withdrawal: 427 MGD


Daily Potomac flow and demand update (Saturday 2019-10-12)

Dry conditions continue, and little rain is in the forecast over the next 7 days.

Recent basin-wide average precipitation (above Little Falls):

(based on CO-OP's Low Flow Forecast System analysis of Middle Atlantic River Forecast Center (MARFC) gridded multisensor precipitation estimates)

Yesterday's area-weighted average basin precip: 0 (inches)

Past 3-day cumulative area-weighted average basin precip: 0.04531 (inches)

Past 7-day cumulative area-weighted average basin precip: 1.08125 (inches)

Daily Flows:

Little Falls gage flow 2019-10-11: 1344 MGD (2080 cfs)

Little Falls gage flow 2019-10-12: 1280 MGD (est., based on recently available real time data) (1980 cfs)

Note: Gage flow at Little Falls is measured after water supply withdrawals.

Point of Rocks flow 2019-10-11: 1396 MGD (2160 cfs)

Point of Rocks flow 2019-10-12: 1487 MGD (est., based on recently available real time data) (2300 cfs)

Yesterday's Net Potomac withdrawal (2019-10-11):

FW Corbalis withdrawal (Potomac): 119 MGD

WSSC Potomac withdrawal: 175 MGD

Aqueduct withdrawal: 151 MGD

Loudoun withdrawal: 10 MGD

Total Potomac withdrawal: 454 MGD


Daily Potomac flow and demand update (Friday 2019-10-11)

According to the Middle Atlantic River Forecast Center, no rain fell in the basin over the past 24 hours. Between 0.1 and 0.75 inches of rain is expected over the next 7 days.

Although flows at the USGS gage at Point of Rocks are currently above 2000 cfs, the trigger for daily monitoring, daily monitoring will be continued at this time due to limited rain in the forecast.  

Recent basin-wide average precipitation (above Little Falls):

(based on CO-OP's Low Flow Forecast System analysis of Middle Atlantic River Forecast Center (MARFC) gridded multisensor precipitation estimates)

Yesterday's area-weighted average basin precip: 0 (inches)

Past 3-day cumulative area-weighted average basin precip: 0.42 (inches)

Past 7-day cumulative area-weighted average basin precip: 1.08 (inches)

Daily Flows:

Little Falls gage flow 2019-10-10: 1293 MGD (2000 cfs)

Little Falls gage flow 2019-10-11: 1396 MGD (est., based on recently available real time data) (2160 cfs)

Note: Gage flow at Little Falls is measured after water supply withdrawals.

Point of Rocks flow 2019-10-10: 1461 MGD (2260 cfs)

Point of Rocks flow 2019-10-11: 1461 MGD (est., based on recently available real time data) (2260 cfs)

Yesterday's Net Potomac withdrawal (2019-10-10):

FW Corbalis withdrawal (Potomac): 106 MGD

WSSC Potomac withdrawal: 175 MGD

Aqueduct withdrawal: 146 MGD

Loudoun withdrawal: 10 MGD

Total Potomac withdrawal: 437 MGD


Daily Potomac flow and demand update (Thursday 2019-10-10)

Potomac River flow at Point of Rocks has increased to a level above 2000 cfs, CO-OP's threshold for daily drought monitoring and reporting. However, little rain is on the horizon and streamflow forecasts indicate that flow will fall back below 2000 cfs within a few days, so we will not discontinue daily drought operations at this time. The Middle Atlantic River Forecast Center predicts up to 1/10 inches of rain in the western portion of the Potomac basin over the next 3 days. Over the next 7 days, accumulations of 1/10 to 1/2 inches are expected in the basin.

Recent basin-wide average precipitation (above Little Falls):

(based on CO-OP's Low Flow Forecast System analysis of Middle Atlantic River Forecast Center (MARFC) gridded multisensor precipitation estimates)

Yesterday's area-weighted average basin precip: 0.04531 (inches)

Past 3-day cumulative area-weighted average basin precip: 0.97196 (inches)

Past 7-day cumulative area-weighted average basin precip: 1.11928 (inches)

Daily Flows:

Little Falls gage flow 2019-10-09: 1189 MGD (1840 cfs)

Little Falls gage flow 2019-10-10: 1312 MGD (est., based on recently available real time data) (2030 cfs)

Note: Gage flow at Little Falls is measured after water supply withdrawals.

Point of Rocks flow 2019-10-09: 1403 MGD (2170 cfs)

Point of Rocks flow 2019-10-10: 1622 MGD (est., based on recently available real time data) (2510 cfs)

Yesterday's Net Potomac withdrawal (2019-10-09):

FW Corbalis withdrawal (Potomac): 105 MGD

WSSC Potomac withdrawal: 169 MGD

Aqueduct withdrawal: 157 MGD

Loudoun withdrawal: 10 MGD

Total Potomac withdrawal: 440 MGD


Daily Potomac flow and demand update (Wednesday 2019-10-09)

According to Middle Atlantic River Forecast Center estimates, 0 to 0.50 inches of rain fell in the basin in the past 24 hours. The CO-OP's Low Flow Forecast System reports that this precipitation amounts to a basin-wide average of 0.37 inches for yesterday. Between 0.10 and 0.50 inches of rain is forecast over the next 7 days.

The USGS gage at Point of Rocks is currently above 2000 cfs, our trigger for daily monitoring. We will continue daily monitoring efforts until we see that flows have significantly improved for several days.

Recent basin-wide average precipitation (above Little Falls):

(based on CO-OP's Low Flow Forecast System analysis of Middle Atlantic River Forecast Center (MARFC) gridded multisensor precipitation estimates)

Yesterday's area-weighted average basin precip: 0.37 (inches)

Past 3-day cumulative area-weighted average basin precip: 1.04 (inches)

Past 7-day cumulative area-weighted average basin precip: 1.07 (inches)

Daily Flows:

Little Falls gage flow 2019-10-08: 1105 MGD (1710 cfs)

Little Falls gage flow 2019-10-09: 1170 MGD (est., based on recently available real time data) (1810 cfs)

Note: Gage flow at Little Falls is measured after water supply withdrawals.

Point of Rocks flow 2019-10-08: 1299 MGD (2010 cfs)

Point of Rocks flow 2019-10-09: 1461 MGD (est., based on recently available real time data) (2260 cfs)

Yesterday's Net Potomac withdrawal (2019-10-08):

FW Corbalis withdrawal (Potomac): 92 MGD

WSSC Potomac withdrawal: 138 MGD

Aqueduct withdrawal: 160 MGD

Loudoun withdrawal: 10 MGD

Total Potomac withdrawal: 400 MGD


Daily Potomac flow and demand update (Tuesday 2019-10-08)

According to Middle Atlantic River Forecast Center estimates, 0 to 1.50 inches of rain fell in the basin in the past 24 hours. The CO-OP's Low Flow Forecast System reports that this precipitation amounts to a basin-wide average of 0.55271 inches for yesterday. Between 0 and 0.25 inches of rain is forecast over the next 7 days.

The USGS gage at Point of Rocks temporarily rose above 2000 cfs due to the recent precipitation. However, flows have already begun to drop below 2000 cfs.

Recent basin-wide average precipitation (above Little Falls):

(based on CO-OP's Low Flow Forecast System analysis of Middle Atlantic River Forecast Center (MARFC) gridded multisensor precipitation estimates)

Yesterday's area-weighted average basin precip: 0.55271 (inches)

Past 3-day cumulative area-weighted average basin precip: 0.662 (inches)

Past 7-day cumulative area-weighted average basin precip: 0.70053 (inches)

Daily Flows:

Little Falls gage flow 2019-10-07: 1079 MGD (1670 cfs)

Little Falls gage flow 2019-10-08: 1086 MGD (est., based on recently available real time data) (1680 cfs)

Note: Gage flow at Little Falls is measured after water supply withdrawals.

Point of Rocks flow 2019-10-07: 1215 MGD (1880 cfs)

Point of Rocks flow 2019-10-08: 1293 MGD (est., based on recently available real time data) (2000 cfs)

Yesterday's Net Potomac withdrawal (2019-10-07):

FW Corbalis withdrawal (Potomac): 112 MGD

WSSC Potomac withdrawal: 143 MGD

Aqueduct withdrawal: 149 MGD

Loudoun withdrawal: 10 MGD

Total Potomac withdrawal: 414 MGD


Daily Potomac flow and demand update (Monday 2019-10-07)

Modest relief from the dry conditions may be on the way - the Middle Atlantic River Forecast Center predicts accumulations of 0.1 to 1.0 inches of rain in the basin over the next 24 hours.

Recent basin-wide average precipitation (above Little Falls):

(based on CO-OP's Low Flow Forecast System analysis of Middle Atlantic River Forecast Center (MARFC) gridded multisensor precipitation estimates)

Yesterday's area-weighted average basin precip: 0.10929 (inches)

Past 3-day cumulative area-weighted average basin precip: 0.11219 (inches)

Past 7-day cumulative area-weighted average basin precip: 0.4966 (inches)

Daily Flows:

Little Falls gage flow 2019-10-06: 1092 MGD (1690 cfs)

Little Falls gage flow 2019-10-07: 1034 MGD (est., based on recently available real time data) (1600 cfs)

Note: Gage flow at Little Falls is measured after water supply withdrawals.

Point of Rocks flow 2019-10-06: 1209 MGD (1870 cfs)

Point of Rocks flow 2019-10-07: 1189 MGD (est., based on recently available real time data) (1840 cfs)

Yesterday's Net Potomac withdrawal (2019-10-06):

FW Corbalis withdrawal (Potomac): 108 MGD

WSSC Potomac withdrawal: 121 MGD

Aqueduct withdrawal: 142 MGD

Loudoun withdrawal: 10 MGD

Total Potomac withdrawal: 381 MGD


Daily Potomac flow and demand update (Sunday 2019-10-06)

According to MARFC's forecasted precipitation, the next 7 days is expected to bring between 0.25 and 1 inch of rain to the basin.

Recent basin-wide average precipitation (above Little Falls):

(based on CO-OP's Low Flow Forecast System analysis of Middle Atlantic River Forecast Center (MARFC) gridded multisensor precipitation estimates)

Yesterday's area-weighted average basin precip: 0 (inches)

Past 3-day cumulative area-weighted average basin precip: 0.04 (inches)

Past 7-day cumulative area-weighted average basin precip: 0.43 (inches)

Daily Flows:

Little Falls gage flow 2019-10-05: 1092 MGD (1690 cfs)

Little Falls gage flow 2019-10-06: 1086 MGD (est., based on recently available real time data) (1680 cfs)

Note: Gage flow at Little Falls is measured after water supply withdrawals.

Point of Rocks flow 2019-10-05: 1150 MGD (1780 cfs)

Point of Rocks flow 2019-10-06: 1189 MGD (est., based on recently available real time data) (1840 cfs)

Yesterday's Net Potomac withdrawal (2019-10-05):

FW Corbalis withdrawal (Potomac): 108 MGD

WSSC Potomac withdrawal: 132 MGD

Aqueduct withdrawal: 163 MGD

Loudoun withdrawal: 10 MGD

Total Potomac withdrawal: 413 MGD


Daily Potomac flow and demand update (Saturday 2019-10-05)

According to Middle Atlantic River Forecast Center estimates, no rain fell in the basin over the past 24 hours. Between 0.01 and 1.25 inches of rain is forecast over the next 7 days.

The USACE's recreational release has passed the Point of Rocks gage and flows at that gage have dropped below 2000 cfs again. MARFC's GEFS predictions are suggesting that some of the precipitation forecast may affect the Point of Rocks gage flow between October 7 and 11, causing flows at that gage to increase slightly.

REVISION Recent basin-wide average precipitation (above Little Falls):

(based on CO-OP's Low Flow Forecast System analysis of Middle Atlantic River Forecast Center (MARFC) gridded multisensor precipitation estimates)

Yesterday's area-weighted average basin precip: 0.0029 (inches)

Past 3-day cumulative area-weighted average basin precip: 0.03817 (inches)

Past 7-day cumulative area-weighted average basin precip: 0.44934 (inches)

Daily Flows:

Little Falls gage flow 2019-10-04: 1267 MGD (1960 cfs)

Little Falls gage flow 2019-10-05: 1086 MGD (est., based on recently available real time data) (1680 cfs)

Note: Gage flow at Little Falls is measured after water supply withdrawals.

Point of Rocks flow 2019-10-04: 1176 MGD (1820 cfs)

Point of Rocks flow 2019-10-05: 1189 MGD (est., based on recently available real time data) (1840 cfs)

Yesterday's Net Potomac withdrawal (2019-10-04):

FW Corbalis withdrawal (Potomac): 126 MGD

WSSC Potomac withdrawal: 143 MGD

Aqueduct withdrawal: 168 MGD

Loudoun withdrawal: 10 MGD

Total Potomac withdrawal: 447 MGD


Daily Potomac flow and demand update (Friday 2019-10-04)

Adams County, PA, and nearby areas saw some rain yesterday. According to the Middle Atlantic River Forecast Center, accumulations of up to 1/10 inches are expected in the far northern portion of the Potomac basin over the next 3 days, primarily in Pennsylvania. The 7-day forecast is not as promising as it was a few days ago, but accumulations of 1/4 to 3/4 inches are expected throughout most of the basin, mostly occurring Sunday through Tuesday.

River flow at Point of Rocks briefly exceeded CO-OP's drought monitoring threshold of 2000 cfs over the past couple days, due to the recent rain and the arrival of the USACE's recreational release last Saturday from Savage Reservoir.

REVISION Recent basin-wide average precipitation (above Little Falls):

(based on CO-OP's Low Flow Forecast System analysis of Middle Atlantic River Forecast Center (MARFC) gridded multisensor precipitation estimates)

Yesterday's area-weighted average basin precip: 0.03513 (inches)

Past 3-day cumulative area-weighted average basin precip: 0.03563 (inches)

Past 7-day cumulative area-weighted average basin precip: 0.44644 (inches)

Daily Flows:

Little Falls gage flow 2019-10-03: 1215 MGD (1880 cfs)

Little Falls gage flow 2019-10-04: 1338 MGD (est., based on recently available real time data) (2070 cfs)

Note: Gage flow at Little Falls is measured after water supply withdrawals.

Point of Rocks flow 2019-10-03: 1293 MGD (2000 cfs)

Point of Rocks flow 2019-10-04: 1222 MGD (est., based on recently available real time data) (1890 cfs)

Yesterday's Net Potomac withdrawal (2019-10-03):

FW Corbalis withdrawal (Potomac): 115 MGD

WSSC Potomac withdrawal: 129 MGD

Aqueduct withdrawal: 168 MGD

Loudoun withdrawal: 10 MGD

Total Potomac withdrawal: 422 MGD


Daily Potomac flow and demand update (Thursday 2019-10-03)

Trace amounts of rain fell over some northern areas of the basin over the past 24 hours according to the Middle Atlantic River Forecast Center.  Forecasts are calling for 0.5 to 1.5 inches of rainfall across much of the basin over the next 7 days.

REVISION Recent basin-wide average precipitation (above Little Falls):

(based on CO-OP's Low Flow Forecast System analysis of Middle Atlantic River Forecast Center (MARFC) gridded multisensor precipitation estimates)

Yesterday's area-weighted average basin precip: 0.00014 (inches)

Past 3-day cumulative area-weighted average basin precip: 0.34928 (inches)

Past 7-day cumulative area-weighted average basin precip: 0.43813 (inches)

Daily Flows:

Little Falls gage flow 2019-10-02: 1112 MGD (1720 cfs)

Little Falls gage flow 2019-10-03: 1144 MGD (est., based on recently available real time data) (1770 cfs)

Note: Gage flow at Little Falls is measured after water supply withdrawals.

Point of Rocks flow 2019-10-02: 1396 MGD (2160 cfs)

Point of Rocks flow 2019-10-03: 1415 MGD (est., based on recently available real time data) (2190 cfs)

Yesterday's Net Potomac withdrawal (2019-10-02):

FW Corbalis withdrawal (Potomac): 129 MGD

WSSC Potomac withdrawal: 151 MGD

Aqueduct withdrawal: 158 MGD

Loudoun withdrawal: 10 MGD

Total Potomac withdrawal: 448 MGD


Daily Potomac flow and demand update (Wednesday 2019-10-02)

According to Middle Atlantic River Forecast Center estimates, no rain fell in the basin in the past 24 hours. However, streamflows have risen slightly due to Monday's rain, and forecasts call for over an inch and a half of rain throughout most of the basin over the next 7 days.

REVISION Recent basin-wide average precipitation (above Little Falls):

(based on CO-OP's Low Flow Forecast System analysis of Middle Atlantic River Forecast Center (MARFC) gridded multisensor precipitation estimates)

Yesterday's area-weighted average basin precip: 0.00036 (inches)

Past 3-day cumulative area-weighted average basin precip: 0.3937 (inches)

Past 7-day cumulative area-weighted average basin precip: 0.43799 (inches)

Daily Flows:

Little Falls gage flow 2019-10-01: 1131 MGD (1750 cfs)

Little Falls gage flow 2019-10-02: 1144 MGD (est., based on recently available real time data) (1770 cfs)

Note: Gage flow at Little Falls is measured after water supply withdrawals.

Point of Rocks flow 2019-10-01: 1150 MGD (1780 cfs)

Point of Rocks flow 2019-10-02: 1383 MGD (est., based on recently available real time data) (2140 cfs)

Yesterday's Net Potomac withdrawal (2019-10-01):

FW Corbalis withdrawal (Potomac): 99 MGD

WSSC Potomac withdrawal: 128 MGD

Aqueduct withdrawal: 158 MGD

Loudoun withdrawal: 10 MGD

Total Potomac withdrawal: 394 MGD


Daily Potomac flow and demand update (Tuesday 2019-10-01)

Yesterday's unexpected showers brought some needed relief to the basin, and streamflows are increasing slightly. According to Middle Atlantic River Forecast Center estimates, most of the basin received between 0.25 to 0.75 inches of rain over the past 24 hours. However, no rain is expected over the next 3 days.

The USACE's recreational release last Saturday from Savage Reservoir is now passing by the USGS's stream gage at Hancock, Maryland - see https://waterdata.usgs.gov/md/nwis/uv/?site_no=01613000&PARAmeter_cd=00065,00060,62615,62620.

REVISION Recent basin-wide average precipitation (above Little Falls):

(based on CO-OP's Low Flow Forecast System analysis of Middle Atlantic River Forecast Center (MARFC) gridded multisensor precipitation estimates)

Yesterday's area-weighted average basin precip: 0.34878 (inches)

Past 3-day cumulative area-weighted average basin precip: 0.41081 (inches)

Past 7-day cumulative area-weighted average basin precip: 0.44028 (inches)

Daily Flows:

Little Falls gage flow 2019-09-30: 989 MGD (1530 cfs)

Little Falls gage flow 2019-10-01: 1144 MGD (est., based on recently available real time data) (1770 cfs)

Note: Gage flow at Little Falls is measured after water supply withdrawals.

Point of Rocks flow 2019-09-30: 1118 MGD (1730 cfs)

Point of Rocks flow 2019-10-01: 1189 MGD (est., based on recently available real time data) (1840 cfs)

Yesterday's Net Potomac withdrawal (2019-09-30):

FW Corbalis withdrawal (Potomac): 113 MGD

WSSC Potomac withdrawal: 139 MGD

Aqueduct withdrawal: 171 MGD

Loudoun withdrawal: 10 MGD

Total Potomac withdrawal: 432 MGD


Daily Potomac flow and demand update (Monday 2019-09-30)

There was no rain in most of the Potomac basin over the past 24 hours, but according to Middle Atlantic River Forecast Center (MARFC) estimates, 0.25 to 0.50 inches of rain fell in a few isolated locations in the western part of the basin yesterday. Forecasts call for the dry conditions to continue, but the MARFC predicts precipitation accumulations of over 0.10 inches in the far western portion of the basin over the next 3 days.

REVISION Recent basin-wide average precipitation (above Little Falls):

(based on CO-OP's Low Flow Forecast System analysis of Middle Atlantic River Forecast Center (MARFC) gridded multisensor precipitation estimates)

Yesterday's area-weighted average basin precip: 0.04456 (inches)

Past 3-day cumulative area-weighted average basin precip: 0.06203 (inches)

Past 7-day cumulative area-weighted average basin precip: 0.11922 (inches)

Daily Flows:

Little Falls gage flow 2019-09-29: 1015 MGD (1570 cfs)

Little Falls gage flow 2019-09-30: 937 MGD (est., based on recently available real time data) (1450 cfs)

Note: Gage flow at Little Falls is measured after water supply withdrawals.

Point of Rocks flow 2019-09-29: 1066 MGD (1650 cfs)

Point of Rocks flow 2019-09-30: 1086 MGD (est., based on recently available real time data) (1680 cfs)

Yesterday's Net Potomac withdrawal (2019-09-29):

FW Corbalis withdrawal (Potomac): 130 MGD

WSSC Potomac withdrawal: 146 MGD

Aqueduct withdrawal: 151 MGD

Loudoun withdrawal: 9 MGD

Total Potomac withdrawal: 436 MGD


Daily Potomac flow and demand update (Sunday 2019-09-29)

According to the Middle Atlantic River Forecast Center, little precipitation fell in the basin over the past 24 hours, and little is expected for the next three days.

The US Army Corps of Engineers made a whitewater recreational release from Savage Reservoir yesterday (Saturday, Sep 28). The release of approximately 1000 cfs occurred from 10 AM to 4 PM. The release is now passing Cumberland, Maryland, and the hydrograph at the USGS's flow monitoring station at Cumberland can be viewed at https://waterdata.usgs.gov/md/nwis/uv/?site_no=01603000&PARAmeter_cd=00065,00060,62615,62620. We expect to see elevated flows from this release at Point of Rocks and Little Falls later this week.

REVISION Recent basin-wide average precipitation (above Little Falls):

(based on CO-OP's Low Flow Forecast System analysis of Middle Atlantic River Forecast Center (MARFC) gridded multisensor precipitation estimates)

Yesterday's area-weighted average basin precip: 0.01747 (inches)

Past 3-day cumulative area-weighted average basin precip: 0.04429 (inches)

Past 7-day cumulative area-weighted average basin precip: 0.08249 (inches)

Daily Flows:

Little Falls gage flow 2019-09-28: 1034 MGD (1600 cfs)

Little Falls gage flow 2019-09-29: 1008 MGD (est., based on recently available real time data) (1560 cfs)

Note: Gage flow at Little Falls is measured after water supply withdrawals.

Point of Rocks flow 2019-09-28: 1086 MGD (1680 cfs)

Point of Rocks flow 2019-09-29: 1047 MGD (est., based on recently available real time data) (1620 cfs)

Yesterday's Net Potomac withdrawal (2019-09-28):

FW Corbalis withdrawal (Potomac): 119 MGD

WSSC Potomac withdrawal: 151 MGD

Aqueduct withdrawal: 156 MGD

Loudoun withdrawal: 10 MGD

Total Potomac withdrawal: 436 MGD


Daily Potomac flow and demand update (Saturday 2019-09-28)

According to Middle Atlantic River Forecast Center estimates, little or no rain fell in the Potomac basin over the past 24 hours. According to forecasts, 0.01 to 0.75 inches of rain is expected for the next 7 days (very little of this rain is expected for the next 5 days).

The USACE Baltimore District Office determines release rates for water quality storage from Jennings Randolph Reservoir and matching release rates from Savage Reservoir. They have scheduled a whitewater recreational release from Savage Reservoir for today (Saturday, Sep 28). The release rate is planned to be 1000 cfs from 10 AM to 4 PM. We expect to see elevated flows from this release at Point of Rocks and Little Falls later next week.

Daily Flows:

Little Falls gage flow 2019-09-27: 1060 MGD (1640 cfs)

Little Falls gage flow 2019-09-28: 1034 MGD (est., based on recently available real time data) (1600 cfs)

Note: Gage flow at Little Falls is measured after water supply withdrawals.

Point of Rocks flow 2019-09-27: 1105 MGD (1710 cfs)

Point of Rocks flow 2019-09-28: 1125 MGD (est., based on recently available real time data) (1740 cfs)

Yesterday's Net Potomac withdrawal (2019-09-27):

FW Corbalis withdrawal (Potomac): 127 MGD

WSSC Potomac withdrawal: 140 MGD

Aqueduct withdrawal: 167 MGD

Loudoun withdrawal: 10 MGD

Total Potomac withdrawal: 444 MGD


Daily Potomac flow and demand update (Friday 2019-09-27)

According to Middle Atlantic River Forecast Center estimates, little or no rain fell in the Potomac basin over the past 72 hours. According to forecasts, no significant rain is expected for the next 7 days.

The USACE Baltimore District Office determines release rates for water quality storage from Jennings Randolph Reservoir and matching release rates from Savage Reservoir. They have scheduled a whitewater recreational release from Savage Reservoir this Saturday, Sep 28. The release rate is planned to be 1000 cfs from 10 AM to 4 PM. We expect to see elevated flows from this release at Point of Rocks and Little Falls later next week.

Daily Flows:

Little Falls gage flow 2019-09-26: 1092 MGD (1690 cfs)

Little Falls gage flow 2019-09-27: 1060 MGD (est., based on recently available real time data) (1640 cfs)

Note: Gage flow at Little Falls is measured after water supply withdrawals.

Point of Rocks flow 2019-09-26: 1131 MGD (1750 cfs)

Point of Rocks flow 2019-09-27: 1125 MGD (est., based on recently available real time data) (1740 cfs)

Yesterday's Net Potomac withdrawal (2019-09-26):

FW Corbalis withdrawal (Potomac): 122 MGD

WSSC Potomac withdrawal: 140 MGD

Aqueduct withdrawal: 159 MGD

Loudoun withdrawal: 10 MGD

Total Potomac withdrawal: 430 MGD


Daily Potomac flow and demand update (Thursday 2019-09-26)

Yesterday brought no relief from the dry conditions in the Potomac basin. The National Weather Service forecasts negligible accumulations of precipitation over the next 7 days.

Daily Flows:

Little Falls gage flow 2019-09-25: 1060 MGD (1640 cfs)

Little Falls gage flow 2019-09-26: 1034 MGD (est., based on recently available real time data) (1600 cfs)

Note: Gage flow at Little Falls is measured after water supply withdrawals.

Point of Rocks flow 2019-09-25: 1170 MGD (1810 cfs)

Point of Rocks flow 2019-09-26: 1163 MGD (est., based on recently available real time data) (1800 cfs)

Yesterday's Net Potomac withdrawal (2019-09-25):

FW Corbalis withdrawal (Potomac): 126 MGD

WSSC Potomac withdrawal: 143 MGD

Aqueduct withdrawal: 165 MGD

Loudoun withdrawal: 10 MGD

Total Potomac withdrawal: 443 MGD


Daily Potomac flow and demand update (Wednesday 2019-09-25)

Dry conditions persist, with negligible precipitation in the Potomac basin over the past several days. The National Weather Service's forecast calls for little rain over the next 7 days.

Daily Flows:

Little Falls gage flow 2019-09-24: 1053 MGD (1630 cfs)

Little Falls gage flow 2019-09-25: 1034 MGD (est., based on recently available real time data) (1600 cfs)

Note: Gage flow at Little Falls is measured after water supply withdrawals.

Point of Rocks flow 2019-09-24: 1144 MGD (1770 cfs)

Point of Rocks flow 2019-09-25: 1222 MGD (est., based on recently available real time data) (1890 cfs)

Yesterday's Net Potomac withdrawal (2019-09-24):

FW Corbalis withdrawal (Potomac): 120 MGD

WSSC Potomac withdrawal: 151 MGD

Aqueduct withdrawal: 166 MGD

Loudoun withdrawal: 10 MGD

Total Potomac withdrawal: 447 MGD


Daily Potomac flow and demand update (Tuesday 2019-09-24)

The Potomac remains dry with 2.8 inches below normal basin average precipitation over the past 30 days. The Middle Atlantic River Forecast Center's  24 and 72 hour precipitation forecast shows 0 to 0.1 inch of precipitation over isolated parts of the basin. The 7-day total precipitation forecast shows 0 to 0.1 inch of precipitation over most of the basin.

Daily Flows:

Little Falls gage flow 2019-09-23: 1034 MGD (1600 cfs)

Little Falls gage flow 2019-09-24: 1034 MGD (est., based on recently available real time data) (1600 cfs)

Note: Gage flow at Little Falls is measured after water supply withdrawals.

Point of Rocks flow 2019-09-23: 1202 MGD (1860 cfs)

Point of Rocks flow 2019-09-24: 1222 MGD (est., based on recently available real time data) (1890 cfs)

Yesterday's Net Potomac withdrawal (2019-09-23):

FW Corbalis withdrawal (Potomac): 135 MGD

WSSC Potomac withdrawal: 163 MGD

Aqueduct withdrawal: 172 MGD

Loudoun withdrawal: 11 MGD

Total Potomac withdrawal: 482 MGD


Initiated Monitoring - Daily Potomac flow and demand update (Monday 2019-09-23)

Potomac River flow at Point of Rocks has dropped below the low-flow threshold of 2,000 cfs. Today CO-OP is initiating daily monitoring and reporting of Potomac flows and withdrawals. Today's report appears below.

Conditions have been dry throughout the basin over the past couple of months. National Weather Service precipitation estimates indicate that the basin received no appreciable rain over the past 7 days, and forecasts call for little rain over the next seven days.

Daily Flows:

Little Falls gage flow 2019-09-22: 1125 MGD (1740 cfs)

Little Falls gage flow 2019-09-23: 1034 MGD (est., based on recently available real time data) (1600 cfs)

Note: Gage flow at Little Falls is measured after water supply withdrawals.

Point of Rocks flow 2019-09-22: 1209 MGD (1870 cfs)

Point of Rocks flow 2019-09-23: 1234 MGD (est., based on recently available real time data) (1910 cfs)

Yesterday's Net Potomac withdrawal (2019-09-22):

FW Corbalis withdrawal (Potomac): 128 MGD

WSSC Potomac withdrawal: 153 MGD

Aqueduct withdrawal: 147 MGD

LW Trap Rock withdrawal: 12 MGD (estimated)

Total Potomac withdrawal: 440 MGD

Note: Potomac River flow at Point of Rocks has dropped below the low-flow threshold of 2,000 cfs. When this occurs, CO-OP begins conducting daily monitoring and reporting of Potomac flows and withdrawals. ICPRB asks that communications be sent by 8:00 am. Reporting can be submitted through www.icprbcoop.org, by email to coop@icprb.org, or by telephone by leaving a message with the CO-OP operations number at 301-274-8132. Thank you for your contribution to the monitoring efforts.


​​Discontinue Monitoring - Daily Potomac flow and demand update (Monday 2017-10-30)

The National Weather Service (NWS) 24 hour observed precipitation shows that there was between 0.10 and 3.00 inches of precipitation in the Potomac basin above Little Falls. The NWS 3-day and 5-day forecasts both predict 0.00 to 0.25 inches of rain in this same area.

The daily average flow at the US Geological Survey gage at Point of Rocks has been above 2,000 cfs, our trigger for daily monitoring, for the past four days. The NWS Global Ensemble Forecast System simulations predict that flow at Point of Rocks may continue to remain above 2,000 cfs for the week. Therefore, daily monitoring will be discontinued until further notice. Thank you to all for your contribution to the monitoring efforts!

Daily Flows:

Little Falls gage flow 2017-10-29: 1590 MGD (2460 cfs)

Little Falls gage flow 2017-10-30: 2120 MGD (est., based on recently available real time data) (3280 cfs)

Note: Gage flow at Little Falls is measured after water supply withdrawals.

Point of Rocks flow 2017-10-29: 1454 MGD (2250 cfs)

Point of Rocks flow 2017-10-30: 2734 MGD (est., based on recently available real time data) (4230 cfs)

​​Net Potomac withdrawal (2017-10-29):

FW Corbalis withdrawal (Potomac): 77 MGD

WSSC Potomac withdrawal: 132 MGD

Aqueduct withdrawal: 116 MGD

Total Potomac withdrawal: 325 MGD


Daily Potomac flow and demand update (Sunday 2017-10-29)

According to the Middle Atlantic River Forecast Center (MARFC), portions of the basin received no rain or trace amounts over the last 24 hours, and the northwestern edge of the basin received up to 2 inches. Over the next day, MARFC predicts 1 to 1 3/4 inches in the drainage area above Little Falls dam.  Although flow at the US Geological Survey gage at Point of Rocks is currently above 2,000 cfs, our trigger for daily monitoring, we will continue daily monitoring efforts until we see that flows have significantly improved for several days.

Daily Flows:

Little Falls gage flow 2017-10-28: 1590 MGD (2460 cfs)

Little Falls gage flow 2017-10-29: 1551 MGD (est., based on recently available real time data) (2400 cfs)

Note: Gage flow at Little Falls is measured after water supply withdrawals.

Point of Rocks flow 2017-10-28: 1364 MGD (2110 cfs)

Point of Rocks flow 2017-10-29: 1338 MGD (est., based on recently available real time data) (2070 cfs)

Net Potomac withdrawal (2017-10-28):

FW Corbalis withdrawal (Potomac): 148 MGD

WSSC Potomac withdrawal: 133 MGD

Aqueduct withdrawal: 128 MGD

Total Potomac withdrawal: 409 MGD


Daily Potomac flow and demand update (Saturday 2017-10-28)

The National Weather Service (NWS) reports that there was no precipitation in the Potomac basin over the last 24 hours. The NWS 3-day forecast predicts 1.25 to 2.0 inches of rain in the portion of the basin above Little Falls dam.  Although flows at the US Geological Survey gage at Point of Rocks is currently above 2,000 cfs, our trigger for daily monitoring, we will continue daily monitoring efforts until we see that flows have significantly improved for several days.

Daily Flows:

Little Falls gage flow 2017-10-27: 1545 MGD (2390 cfs)

Little Falls gage flow 2017-10-28: 1616 MGD (est., based on recently available real time data) (2500 cfs)

Note: Gage flow at Little Falls is measured after water supply withdrawals.

Point of Rocks flow 2017-10-27: 1370 MGD (2120 cfs)

Point of Rocks flow 2017-10-28: 1564 MGD (est., based on recently available real time data) (2420 cfs)

Net Potomac withdrawal (2017-10-27):

FW Corbalis withdrawal (Potomac): 155 MGD

WSSC Potomac withdrawal: 132 MGD

Aqueduct withdrawal: 127 MGD

Total Potomac withdrawal: 415 MGD


Daily Potomac flow and demand update (Friday 2017-10-27)

The National Weather Service (NWS) 24 hour observed precipitation shows that there were scattered, trace amounts of rain in the Potomac basin above Little Falls. The NWS 3-day forecast predicts 0.75 to 1.5 inches of rain in this same area. The National Weather Service (NWS) 5-day forecast predicts accumulations of up to 2.5 inches of rain in the Potomac basin. Although flows at the US Geological Survey gage at Point of Rocks is currently above 2,000 cfs, our trigger for daily monitoring, we will continue daily monitoring efforts until we see that flows have significantly improved for several days.

Daily Flows:

Little Falls gage flow 2017-10-26: 1474 MGD (2280 cfs)

Little Falls gage flow 2017-10-27: 1487 MGD (est., based on recently available real time data) (2300 cfs)

Note: Gage flow at Little Falls is measured after water supply withdrawals.

Point of Rocks flow 2017-10-26: 1331 MGD (2060 cfs)

Point of Rocks flow 2017-10-27: 1506 MGD (est., based on recently available real time data) (2330 cfs)

Net Potomac withdrawal (2017-10-26):

FW Corbalis withdrawal (Potomac): 84 MGD

WSSC Potomac withdrawal: 116 MGD

Aqueduct withdrawal: 129 MGD

Total Potomac withdrawal: 329 MGD


Daily Potomac flow and demand update (Thursday 2017-10-26)

The National Weather Service (NWS) 24 hour observed precipitation shows that there were scattered, trace amounts of rain in the Potomac basin above Little Falls. The NWS 3-day forecast predicts 0 to 0.5 inches of rain in this same area with the largest amounts expected in the western portions of the basin. The National Weather Service (NWS) 5-day forecast predicts accumulations of up to 1.75 inches of rain in the Potomac basin. Although flows at the US Geological Survey gage at Point of Rocks is currently above 2,000 cfs, our trigger for daily monitoring, we will continue daily monitoring efforts until we see that flows have significantly improved for several days.

Daily Flows:

Little Falls gage flow 2017-10-25: 1512 MGD (2340 cfs)

Little Falls gage flow 2017-10-26: 1428 MGD (est., based on recently available real time data) (2210 cfs)

Note: Gage flow at Little Falls is measured after water supply withdrawals.

Point of Rocks flow 2017-10-25: 1228 MGD (1900 cfs)

Point of Rocks flow 2017-10-26: 1461 MGD (est., based on recently available real time data) (2260 cfs)

Net Potomac withdrawal (2017-10-25):

FW Corbalis withdrawal (Potomac): 85 MGD

WSSC Potomac withdrawal: 125 MGD

Aqueduct withdrawal: 130 MGD

Total Potomac withdrawal: 340 MGD


Daily Potomac flow and demand update (Wednesday 2017-10-25)

The National Weather Service (NWS) 24 hour observed precipitation shows that there was 0.00 to 0.50 inches of rain in the Potomac basin above Little Falls. The NWS 3-day forecast predicts no rain over the majority of this same area. The US Geological Survey shows that Point of Rocks flow fell below and then rose above 2,000 cfs, our trigger for daily monitoring. We will continue daily monitoring efforts until we see that flows have significantly improved for several days.

Daily Flows:

Little Falls gage flow 2017-10-24: 1247 MGD (1930 cfs)

Little Falls gage flow 2017-10-25: 1519 MGD (est., based on recently available real time data) (2350 cfs)

Note: Gage flow at Little Falls is measured after water supply withdrawals.

Point of Rocks flow 2017-10-24: 1202 MGD (1860 cfs)

Point of Rocks flow 2017-10-25: 1338 MGD (est., based on recently available real time data) (2070 cfs)

Net Potomac withdrawal (2017-10-24):

FW Corbalis withdrawal (Potomac): 79 MGD

WSSC Potomac withdrawal: 125 MGD

Aqueduct withdrawal: 135 MGD

Total Potomac withdrawal: 339 MGD


Daily Potomac flow and demand update (Tuesday 2017-10-24)

The National Weather Service (NWS) 24 hour observed precipitation shows that there was 0.01 to 1.25 inches of rain in the Potomac basin above Little Falls. The NWS 3-day forecast predicts accumulations of 0.25 to 1.50 inches of rain over this same area. The US Geological Survey shows that Point of Rocks flow rose above 2,000 cfs, our trigger for daily monitoring. We will continue daily monitoring efforts until we see that flows have significantly improved for several days.

Daily Flows:

Little Falls gage flow 2017-10-23: 1099 MGD (1700 cfs)

Little Falls gage flow 2017-10-24: 1086 MGD (est., based on recently available real time data) (1680 cfs)

Note: Gage flow at Little Falls is measured after water supply withdrawals.

Point of Rocks flow 2017-10-23: 1053 MGD (1630 cfs)

Point of Rocks flow 2017-10-24: 1370 MGD (est., based on recently available real time data) (2120 cfs)

Net Potomac withdrawal (2017-10-23):

FW Corbalis withdrawal (Potomac): 94 MGD

WSSC Potomac withdrawal: 150 MGD

Aqueduct withdrawal: 136 MGD

Total Potomac withdrawal: 380 MGD


Daily Potomac flow and demand update (Monday 2017-10-23)

The National Weather Service (NWS) 24 hour observed precipitation shows that there was 0 inches of rain in the Potomac basin above Little Falls. The NWS 3-day forecast predicts accumulations of 0.50 to 1.25 inches of rain over this same area. The NWS Global Ensemble Forecast System simulations predict that flow at Point of Rocks may rise above 2000 cfs, our trigger for daily drought monitoring, sometime this week.

Daily Flows:

Little Falls gage flow 2017-10-22: 1228 MGD (1900 cfs)

Little Falls gage flow 2017-10-23: 1060 MGD (est., based on recently available real time data) (1640 cfs)

Note: Gage flow at Little Falls is measured after water supply withdrawals.

Point of Rocks flow 2017-10-22: 1028 MGD (1590 cfs)

Point of Rocks flow 2017-10-23: 1034 MGD (est., based on recently available real time data) (1600 cfs)

Net Potomac withdrawal (2017-10-22):

FW Corbalis withdrawal (Potomac): 104 MGD

WSSC Potomac withdrawal: 132 MGD

Aqueduct withdrawal: 125 MGD

Total Potomac withdrawal: 361 MGD


Daily Potomac flow and demand update (Sunday 2017-10-22)

No rain fell in the basin over the past 24 hours. The National Weather Service (NWS) 3-day forecast predicts accumulations of 0.5 to 1 inch of rain across the basin. The NWS 5-day forecast predicts accumulations of up to 1.75 inches of rain in the Potomac basin.

Daily Flows:

Little Falls gage flow 2017-10-21: 1280 MGD (1980 cfs)

Little Falls gage flow 2017-10-22: 1170 MGD (est., based on recently available real time data) (1810 cfs)

Note: Gage flow at Little Falls is measured after water supply withdrawals.

Point of Rocks flow 2017-10-21: 1138 MGD (1760 cfs)

Point of Rocks flow 2017-10-22: 1008 MGD (est., based on recently available real time data) (1560 cfs)

Net Potomac withdrawal (2017-10-21):

FW Corbalis withdrawal (Potomac): 89 MGD

WSSC Potomac withdrawal: 132 MGD

Aqueduct withdrawal: 137 MGD

Total Potomac withdrawal: 358 MGD


Daily Potomac flow and demand update (Saturday 2017-10-21)

No rain fell in the basin over the past 24 hours. Flow at Point of Rocks is currently at about 1900 cfs. The National Weather Service (NWS) 3-day forecast predicts accumulations of 0.01 to 0.10 inches in the western part of the Potomac basin. The NWS 5-day forecast predicts accumulations of up to 1.25 inches of rain in the Potomac basin.

Daily Flows:

Little Falls gage flow 2017-10-20: 1331 MGD (2060 cfs)

Little Falls gage flow 2017-10-21: 1280 MGD (est., based on recently available real time data) (1980 cfs)

Note: Gage flow at Little Falls is measured after water supply withdrawals.

Point of Rocks flow 2017-10-20: 1144 MGD (1770 cfs)

Point of Rocks flow 2017-10-21: 1234 MGD (est., based on recently available real time data) (1910 cfs)

Net Potomac withdrawal (2017-10-20):

FW Corbalis withdrawal (Potomac): 98 MGD

WSSC Potomac withdrawal: 133 MGD

Aqueduct withdrawal: 132 MGD

Total Potomac withdrawal: 363 MGD


Daily Potomac flow and demand update (Friday 2017-10-20)

Flow at Point of Rocks is currently at about 2000 cfs, CO-OP's trigger for daily drought monitoring. No rain fell in the basin over the past 24 hours, and no rain is expected over the next 72 hours, according to the Middle Atlantic River Forecast Center's quantitative precipitation forecasts. The National Weather Service (NWS) 5-day forecast predicts accumulations of up to 1.25 inches of rain in the Potomac basin.

Daily Flows:

Little Falls gage flow 2017-10-19: 1558 MGD (2410 cfs)

Little Falls gage flow 2017-10-20: 1338 MGD (est., based on recently available real time data) (2070 cfs)

Note: Gage flow at Little Falls is measured after water supply withdrawals.

Point of Rocks flow 2017-10-19: 1176 MGD (1820 cfs)

Point of Rocks flow 2017-10-20: 1293 MGD (est., based on recently available real time data) (2000 cfs)

Net Potomac withdrawal (2017-10-19):

FW Corbalis withdrawal (Potomac): 87 MGD

WSSC Potomac withdrawal: 135 MGD

Aqueduct withdrawal: 145 MGD

Total Potomac withdrawal: 367 MGD


Daily Potomac flow and demand update (Friday 2017-10-13)

Point of Rocks flow is at 3110 cfs. Within the last 24 hours, the Potomac basin has received up to 0.1 inches of precipitation. The National Weather Service (NWS) 3-day forecast predicts accumulations of 0.25 inches of rain in the Potomac basin above Little Falls.

With rain continuing to fall across much of the basin, and Point of Rocks flow being above the low flow monitoring threshold of 2,000 cfs, daily monitoring will be discontinued until further notice. Thank you to all for your contribution to the monitoring efforts.

Daily Flows:

Little Falls gage flow 2017-10-12: 1965 MGD (3040 cfs)

Little Falls gage flow 2017-10-13: 1978 MGD (est., based on recently available real time data) (3060 cfs)

Note: Gage flow at Little Falls is measured after water supply withdrawals.

Point of Rocks flow 2017-10-12: 1667 MGD (2580 cfs)

Point of Rocks flow 2017-10-13: 2010 MGD (est., based on recently available real time data) (3110 cfs)

Net Potomac withdrawal (2017-10-12):

FW Corbalis withdrawal (Potomac): 82 MGD

WSSC Potomac withdrawal: 128 MGD

Aqueduct withdrawal: 136 MGD

Total Potomac withdrawal: 345 MGD


Daily Potomac flow and demand update (Thursday 2017-10-12)

The National Weather Service (NWS) 24 hour observed precipitation shows that there was 0.10 to 1.75 inches of rain in the Potomac basin above Little Falls. The NWS 3-day forecast predicts accumulations of 0.01 to 0.75 inches of rain over this same area. The US Geological Survey shows that Point of Rocks flow has remained above 2,000 cfs, our trigger for daily monitoring, since yesterday. The NWS Global Ensemble Forecast System simulations predict that flow at Point of Rocks will continue to rise above 2,000 cfs for the next couple of days. We will continue daily monitoring efforts until we see that flows have significantly improved for several days.

Daily Flows:

Little Falls gage flow 2017-10-11: 1448 MGD (2240 cfs)

Little Falls gage flow 2017-10-12: 1842 MGD (est., based on recently available real time data) (2850 cfs)

Note: Gage flow at Little Falls is measured after water supply withdrawals.

Point of Rocks flow 2017-10-11: 1351 MGD (2090 cfs)

Point of Rocks flow 2017-10-12: 1609 MGD (est., based on recently available real time data) (2490 cfs)

Net Potomac withdrawal (2017-10-11):

FW Corbalis withdrawal (Potomac): 100 MGD

WSSC Potomac withdrawal: 115 MGD

Aqueduct withdrawal: 144 MGD

Total Potomac withdrawal: 359 MGD


Daily Potomac flow and demand update (Wednesday 2017-10-11)

The National Weather Service (NWS) 24 hour observed precipitation shows that there was 0.00 to 0.50 inches of rain in the Potomac basin above Little Falls. The NWS 3-day forecast predicts accumulations of 0.50 to 1.50 inches of rain over this same area. The US Geological Survey shows that Point of Rocks flow has been fluctuating around 2,000 cfs, our trigger for daily monitoring, since yesterday. The NWS Global Ensemble Forecast System simulations predict that flow at Point of Rocks will continue to rise above 2,000 cfs. We will continue daily monitoring efforts until we see that flows have significantly improved for several days.

Daily Flows:

Little Falls gage flow 2017-10-10: 1176 MGD (1820 cfs)

Little Falls gage flow 2017-10-11: 1396 MGD (est., based on recently available real time data) (2160 cfs)

Note: Gage flow at Little Falls is measured after water supply withdrawals.

Point of Rocks flow 2017-10-10: 1267 MGD (1960 cfs)

Point of Rocks flow 2017-10-11: 1383 MGD (est., based on recently available real time data) (2140 cfs)

Net Potomac withdrawal (2017-10-10):

FW Corbalis withdrawal (Potomac): 85 MGD

WSSC Potomac withdrawal: 127 MGD

Aqueduct withdrawal: 137 MGD

Total Potomac withdrawal: 349 MGD


Daily Potomac flow and demand update (Tuesday 2017-10-10)

The National Weather Service (NWS) 24 hour observed precipitation shows that there was 0.00 to 1.50 inches of rain in the Potomac basin above Little Falls. The NWS 3-day forecast predicts accumulations of 0.25 to 1.25 inches of rain over this same area. The NWS Global Ensemble Forecast System simulations predict that flow at Point of Rocks will temporarily rise above 2,000 cfs, our trigger for daily drought monitoring, as earlier as sometime today.

Daily Flows:

Little Falls gage flow 2017-10-09: 1053 MGD (1630 cfs)

Little Falls gage flow 2017-10-10: 1112 MGD (est., based on recently available real time data) (1720 cfs)

Note: Gage flow at Little Falls is measured after water supply withdrawals.

Point of Rocks flow 2017-10-09: 1079 MGD (1670 cfs)

Point of Rocks flow 2017-10-10: 1280 MGD (est., based on recently available real time data) (1980 cfs)

Net Potomac withdrawal (2017-10-09):

FW Corbalis withdrawal (Potomac): 106 MGD

WSSC Potomac withdrawal: 147 MGD

Aqueduct withdrawal: 134 MGD

Total Potomac withdrawal: 386 MGD


Daily Potomac flow and demand update (Monday 2017-10-09)

The National Weather Service (NWS) 24 hour observed precipitation shows that there was 0.25 to 1.75 inches of rain in the Potomac basin above Little Falls. The NWS 3-day forecast predicts accumulations of 0.40 to 1.75 inches of rain over this same area. The NWS Global Ensemble Forecast System simulations predict that flow at Point of Rocks will rise above 2,000 cfs, our trigger for daily drought monitoring, over the coming week.

Daily Flows:

Little Falls gage flow 2017-10-08: 860 MGD (1330 cfs)

Little Falls gage flow 2017-10-09: 957 MGD (est., based on recently available real time data) (1480 cfs)

Note: Gage flow at Little Falls is measured after water supply withdrawals.

Point of Rocks flow 2017-10-08: 840 MGD (1300 cfs)

Point of Rocks flow 2017-10-09: 957 MGD (est., based on recently available real time data) (1480 cfs)

Net Potomac withdrawal (2017-10-08):

FW Corbalis withdrawal (Potomac): 95 MGD

WSSC Potomac withdrawal: 136 MGD

Aqueduct withdrawal: 133 MGD

Total Potomac withdrawal: 363 MGD


Daily Potomac flow and demand update (Sunday 2017-10-08)

According to the Middle Atlantic River Forecast Center's observed precipitation, there was 0.01 to 0.25 inches of precipitation above the Point of Rocks streamflow gage over the last 24 hours. The National Weather Service (NWS) 3-day forecast predicts accumulations of 0.75 to 1.75 inches of rain in the Potomac basin above Little Falls. The NWS Global Ensemble Forecast System simulations predict that flow at Point of Rocks will rise above 2000 cfs, our trigger for daily drought monitoring, over the coming week.

Daily Flows:

Little Falls gage flow 2017-10-07: 866 MGD (1340 cfs)

Little Falls gage flow 2017-10-08: 814 MGD (est., based on recently available real time data) (1260 cfs)

Note: Gage flow at Little Falls is measured after water supply withdrawals.

Point of Rocks flow 2017-10-07: 918 MGD (1420 cfs)

Point of Rocks flow 2017-10-08: 860 MGD (est., based on recently available real time data) (1330 cfs)

Net Potomac withdrawal (2017-10-07):

FW Corbalis withdrawal (Potomac): 104 MGD

WSSC Potomac withdrawal: 136 MGD

Aqueduct withdrawal: 146 MGD

Total Potomac withdrawal: 386 MGD


Daily Potomac flow and demand update (Saturday 2017-10-07)

The National Weather Service (NWS) 3-day forecast predicts accumulations of 1 1/4 to 2 inches of rain in the Potomac basin above Little Falls. The NWS Global Ensemble Forecast System simulations predict that flow at Point of Rocks will rise above 2000 cfs, our trigger for daily drought monitoring, over the coming week.

Daily Flows:

Little Falls gage flow 2017-10-06: 918 MGD (1420 cfs)

Little Falls gage flow 2017-10-07: 860 MGD (est., based on recently available real time data) (1330 cfs)

Note: Gage flow at Little Falls is measured after water supply withdrawals.

Point of Rocks flow 2017-10-06: 892 MGD (1380 cfs)

Point of Rocks flow 2017-10-07: 879 MGD (est., based on recently available real time data) (1360 cfs)

Net Potomac withdrawal (2017-10-06):

FW Corbalis withdrawal (Potomac): 109 MGD

WSSC Potomac withdrawal: 143 MGD

Aqueduct withdrawal: 157 MGD

Total Potomac withdrawal: 409 MGD


Daily Potomac flow and demand update (Friday 2017-10-06)

The Middle Atlantic Forecast Center forecasts approximately an inch of rain in the basin over the next three days.

Daily Flows:

Little Falls gage flow 2017-10-05: 821 MGD (1270 cfs)

Little Falls gage flow 2017-10-06: 885 MGD (est., based on recently available real time data) (1370 cfs)

Note: Gage flow at Little Falls is measured after water supply withdrawals.

Point of Rocks flow 2017-10-05: 976 MGD (1510 cfs)

Point of Rocks flow 2017-10-06: 918 MGD (est., based on recently available real time data) (1420 cfs)

Net Potomac withdrawal (2017-10-05):

FW Corbalis withdrawal (Potomac): 111 MGD

WSSC Potomac withdrawal: 136 MGD

Aqueduct withdrawal: 145 MGD

Total Potomac withdrawal: 392 M


Daily Potomac flow and demand update (Thursday 2017-10-05)

One to two inches of rain is expected over the next 7 days.

Daily Flows:

Little Falls gage flow 2017-10-04: 840 MGD (1300 cfs)

Little Falls gage flow 2017-10-05: 769 MGD (est., based on recently available real time data) (1190 cfs)

Note: Gage flow at Little Falls is measured after water supply withdrawals.

Point of Rocks flow 2017-10-04: 931 MGD (1440 cfs)

Point of Rocks flow 2017-10-05: 1034 MGD (est., based on recently available real time data) (1600 cfs)

Net Potomac withdrawal (2017-10-04):

FW Corbalis withdrawal (Potomac): 112 MGD

WSSC Potomac withdrawal: 130 MGD

Aqueduct withdrawal: 139 MGD

Total Potomac withdrawal: 381 MGD


Daily Potomac flow and demand update (Wednesday 2017-10-04)

The National Weather Services 7-day quantitative precipitation forecast continues to look promising.

Daily Flows:

Little Falls gage flow 2017-10-03: 808 MGD (1250 cfs)

Little Falls gage flow 2017-10-04: 814 MGD (est., based on recently available real time data) (1260 cfs)

Note: Gage flow at Little Falls is measured after water supply withdrawals.

Point of Rocks flow 2017-10-03: 885 MGD (1370 cfs)

Point of Rocks flow 2017-10-04: 873 MGD (est., based on recently available real time data) (1350 cfs)

Net Potomac withdrawal (2017-10-03):

FW Corbalis withdrawal (Potomac): 107 MGD

WSSC Potomac withdrawal: 136 MGD

Aqueduct withdrawal: 147 MGD

Total Potomac withdrawal: 391 MGD


Daily Potomac flow and demand update (Tuesday 2017-10-03)

The National Weather Service's 7-day quantitative precipitation forecast indicates that the basin could receive 1/2 inch to 1 inch of rain at the beginning of next week.

Daily Flows:

Little Falls gage flow 2017-10-02: 827 MGD (1280 cfs)

Little Falls gage flow 2017-10-03: 814 MGD (est., based on recently available real time data) (1260 cfs)

Note: Gage flow at Little Falls is measured after water supply withdrawals.

Point of Rocks flow 2017-10-02: 847 MGD (1310 cfs)

Point of Rocks flow 2017-10-03: 905 MGD (est., based on recently available real time data) (1400 cfs)

Net Potomac withdrawal (2017-10-02):

FW Corbalis withdrawal (Potomac): 119 MGD

WSSC Potomac withdrawal: 139 MGD

Aqueduct withdrawal: 130 MGD

Total Potomac withdrawal: 388 MGD


Daily Potomac flow and demand update (Monday 2017-10-02)

River flows continue to fall. It looks like the western portion of the basin could receive some rain toward the end of the next 7-day period.

Daily Flows:

Little Falls gage flow 2017-10-01: 873 MGD (1350 cfs)

Little Falls gage flow 2017-10-02: 840 MGD (est., based on recently available real time data) (1300 cfs)

Note: Gage flow at Little Falls is measured after water supply withdrawals.

Point of Rocks flow 2017-10-01: 892 MGD (1380 cfs)

Point of Rocks flow 2017-10-02: 834 MGD (est., based on recently available real time data) (1290 cfs)

Net Potomac withdrawal (2017-10-01):

FW Corbalis withdrawal (Potomac): 102 MGD

WSSC Potomac withdrawal: 133 MGD

Aqueduct withdrawal: 137 MGD

Total Potomac withdrawal: 372 MGD


Daily Potomac flow and demand update (Sunday 2017-10-01)

No change in weather conditions is expected over the next week. The US Army Corps of Engineers made the season's final whitewater release yesterday from Savage Reservoir: 1000 cfs from 10 AM to 4 PM. More information on North Branch Potomac releases can be found at http://www.nab-wc.usace.army.mil/northBranch.html.

Daily Flows:

Little Falls gage flow 2017-09-30: 873 MGD (1350 cfs)

Little Falls gage flow 2017-10-01: 860 MGD (est., based on recently available real time data) (1330 cfs)

Note: Gage flow at Little Falls is measured after water supply withdrawals.

Point of Rocks flow 2017-09-30: 905 MGD (1400 cfs)

Point of Rocks flow 2017-10-01: 879 MGD (est., based on recently available real time data) (1360 cfs)

Net Potomac withdrawal (2017-09-30):

FW Corbalis withdrawal (Potomac): 107 MGD

WSSC Potomac withdrawal: 125 MGD

Aqueduct withdrawal: 142 MGD

Total Potomac withdrawal: 374 MGD


Daily Potomac flow and demand update (Saturday 2017-09-30)

The National Weather Service forecasts that dry conditions will continue in the basin over the next 7 days.

Daily Flows:

Little Falls gage flow 2017-09-29: 853 MGD (1320 cfs)

Little Falls gage flow 2017-09-30: 860 MGD (est., based on recently available real time data) (1330 cfs)

Note: Gage flow at Little Falls is measured after water supply withdrawals.

Point of Rocks flow 2017-09-29: 944 MGD (1460 cfs)

Point of Rocks flow 2017-09-30: 918 MGD (est., based on recently available real time data) (1420 cfs)

Net Potomac withdrawal (2017-09-29):

FW Corbalis withdrawal (Potomac): 108 MGD

WSSC Potomac withdrawal: 139 MGD

Aqueduct withdrawal: 155 MGD

Total Potomac withdrawal: 402 MGD


Daily Potomac flow and demand update (Friday 2017-09-29)

National Weather Service forecasts indicates that the basin will have no relief from the dry weather over the next week. Potomac River flow at Point of Rocks is now close to its 25th percentile level for this day of the year.

The daily flow and demand update was inadvertently not sent out yesterday. Yesterday's reported demand values appear at the end of today's report.

Daily Flows:

Little Falls gage flow 2017-09-28: 918 MGD (1420 cfs)

Little Falls gage flow 2017-09-29: 860 MGD (est., based on recently available real time data) (1330 cfs)

Note: Gage flow at Little Falls is measured after water supply withdrawals.

Point of Rocks flow 2017-09-28: 969 MGD (1500 cfs)

Point of Rocks flow 2017-09-29: 957 MGD (est., based on recently available real time data) (1480 cfs)

Net Potomac withdrawal (2017-09-28):

FW Corbalis withdrawal (Potomac): 111 MGD

WSSC Potomac withdrawal: 137 MGD

Aqueduct withdrawal: 153 MGD

Total Potomac withdrawal: 401 MGD

Net Potomac withdrawal (2017-09-27):

FW Corbalis withdrawal (Potomac): 123 MGD

WSSC Potomac withdrawal: 125 MGD

Aqueduct withdrawal: 157 MGD

Total Potomac withdrawal: 405 MGD


Daily Potomac flow and demand update (Wednesday 2017-09-27)

Forecasts indicate that dry conditions will continue for at least the next 7 days.

Daily Flows:

Little Falls gage flow 2017-09-26: 969 MGD (1500 cfs)

Little Falls gage flow 2017-09-27: 982 MGD (est., based on recently available real time data) (1520 cfs)

Note: Gage flow at Little Falls is measured after water supply withdrawals.

Point of Rocks flow 2017-09-26: 1079 MGD (1670 cfs)

Point of Rocks flow 2017-09-27: 1034 MGD (est., based on recently available real time data) (1600 cfs)

Net Potomac withdrawal (2017-09-26):

FW Corbalis withdrawal (Potomac): 116 MGD

WSSC Potomac withdrawal: 138 MGD

Aqueduct withdrawal: 148 MGD

Total Potomac withdrawal: 402 MGD


Daily Potomac flow and demand update (Tuesday 2017-09-26)

Dry conditions are expected to continue over the next week.

Daily Flows:

Little Falls gage flow 2017-09-25: 1021 MGD (1580 cfs)

Little Falls gage flow 2017-09-26: 957 MGD (est., based on recently available real time data) (1480 cfs)

Note: Gage flow at Little Falls is measured after water supply withdrawals.

Point of Rocks flow 2017-09-25: 1028 MGD (1590 cfs)

Point of Rocks flow 2017-09-26: 1125 MGD (est., based on recently available real time data) (1740 cfs)

Net Potomac withdrawal (2017-09-25):

FW Corbalis withdrawal (Potomac): 123 MGD

WSSC Potomac withdrawal: 144 MGD

Aqueduct withdrawal: 145 MGD

Total Potomac withdrawal: 412 MGD



Daily Potomac flow and demand update (Monday 2017-09-25)

Potomac basin stream flows continue to fall. The 7-day forecast indicates that dry conditions will persist.

Daily Flows:

Little Falls gage flow 2017-09-24: 1138 MGD (1760 cfs)

Little Falls gage flow 2017-09-25: 1034 MGD (est., based on recently available real time data) (1600 cfs)

Note: Gage flow at Little Falls is measured after water supply withdrawals.

Point of Rocks flow 2017-09-24: 1021 MGD (1580 cfs)

Point of Rocks flow 2017-09-25: 1021 MGD (est., based on recently available real time data) (1580 cfs)

Net Potomac Production (2017-09-24):

FW Corbalis raw water withdrawal (Potomac): 106 MGD

WSSC Potomac Production: 119 MGD

Aqueduct withdrawal: 140 MGD

Total Potomac demand: 364 MGD


Daily Potomac flow and demand update (Sunday, 2017-09-24)

The Middle Atlantic River Forecast Center (MARFC) predicts no rain in the basin over the next 3 days.

Daily Flows:

Little Falls gage flow 2017-09-23: 1222 MGD (1890 cfs)

Little Falls gage flow 2017-09-24: 1144 MGD (est., based on recently available real time data) (1770 cfs)

Note: Gage flow at Little Falls is measured after water supply withdrawals.

Point of Rocks flow 2017-09-23: 1105 MGD (1710 cfs)

Point of Rocks flow 2017-09-24: 1034 MGD (est., based on recently available real time data) (1600 cfs)

Net Potomac Production (2017-09-23):

FW Corbalis raw water withdrawal (Potomac): 105 MGD

WSSC Potomac Production: 142 MGD

Aqueduct withdrawal: 143 MGD

Total Potomac demand: 390 MGD


Daily Potomac flow and demand update (Saturday 2017-09-23)

Stream flows in the Potomac basin continue to slowly decline. The National Weather Service (NWS) quantitative prediction forecast indicates that less than 1/10 inch of rain will fall in the basin over the next seven day period.

Daily Flows:

Little Falls gage flow 2017-09-22: 1351 MGD (2090 cfs)

Little Falls gage flow 2017-09-23: 1254 MGD (est., based on recently available real time data) (1940 cfs)

Note: Gage flow at Little Falls is measured after water supply withdrawals.

Point of Rocks flow 2017-09-22: 1189 MGD (1840 cfs)

Point of Rocks flow 2017-09-23: 1163 MGD (est., based on recently available real time data) (1800 cfs)

Net Potomac Production (2017-09-22):

FW Corbalis raw water withdrawal (Potomac): 120 MGD

WSSC Potomac Production: 125 MGD

Aqueduct withdrawal: 143 MGD

Total Potomac demand: 387 MGD


Daily Potomac flow and demand update (Friday 2017-09-22)

The 7-day forecast calls for dry conditions throughout the Potomac basin. Flows in the river are at typical levels for this time of year.

Daily Flows:

Little Falls gage flow 2017-09-21: 1293 MGD (2000 cfs)

Little Falls gage flow 2017-09-22: 1338 MGD (est., based on recently available real time data) (2070 cfs)

Note: Gage flow at Little Falls is measured after water supply withdrawals.

Point of Rocks flow 2017-09-21: 1377 MGD (2130 cfs)

Point of Rocks flow 2017-09-22: 1280 MGD (est., based on recently available real time data) (1980 cfs)

Net Potomac Production (2017-09-21):

FW Corbalis raw water withdrawal (Potomac): 107 MGD

WSSC Potomac Production: 119 MGD

Aqueduct withdrawal: 139 MGD

Total Potomac demand: 364 MGD


Daily Potomac flow and demand update (Thursday 2017-09-21)

Flow at Point of Rocks is currently elevated because of two water quality releases made by the Corps last weekend from Jennings Randolph Reservoir. NWS forecasts indicate that dry conditions will persist for the next week.

Daily Flows:

Little Falls gage flow 2017-09-20: 1260 MGD (1950 cfs)

Little Falls gage flow 2017-09-21: 1254 MGD (est., based on recently available real time data) (1940 cfs)

Note: Gage flow at Little Falls is measured after water supply withdrawals.

Point of Rocks flow 2017-09-20: 1325 MGD (2050 cfs)

Point of Rocks flow 2017-09-21: 1506 MGD (est., based on recently available real time data) (2330 cfs)

Net Potomac Production (2017-09-20):

FW Corbalis raw water withdrawal (Potomac): 109 MGD

WSSC Potomac Production: 145 MGD

Aqueduct withdrawal: 139 MGD

Total Potomac demand: 393 MGD


Daily Potomac flow and demand update (Wednesday 2017-09-20)

Flow at Point of Rocks is currently at about 2000 cfs, CO-OP's trigger for daily drought monitoring. But the likely cause of this rise in flow is the Corps' AVF release on Saturday, Sep 16th. National Weather Service (NWS) forecasts indicate that dry conditions will continue in the basin for the next 7 days.

Daily Flows:

Little Falls gage flow 2017-09-19: 1267 MGD (1960 cfs)

Little Falls gage flow 2017-09-20: 1280 MGD (est., based on recently available real time data) (1980 cfs)

Note: Gage flow at Little Falls is measured after water supply withdrawals.

Point of Rocks flow 2017-09-19: 1247 MGD (1930 cfs)

Point of Rocks flow 2017-09-20: 1351 MGD (est., based on recently available real time data) (2090 cfs)

Net Potomac Production (2017-09-19):

FW Corbalis raw water withdrawal (Potomac): 106 MGD

WSSC Potomac Production: 146 MGD

Aqueduct withdrawal: 145 MGD

Total Potomac demand: 397 MGD


Daily Potomac flow and demand update (Tuesday 2017-09-19)

Potomac River flow at Point of Rocks is hovering around 2000 cfs, the trigger for CO-OP daily drought monitoring. It should be noted that flows in the river are not particularly low for this time of year - 2000 cfs is close to the median flow at Point of Rocks in mid-September. The National Weather Service forecast calls for little rain over the next seven days.

The US Army Corps of Engineers made two "artificially varied flow" releases, each of over 1000 cfs and of approximately 12 hour duration, last Saturday and Sunday, Sep 16 and 17. These releases are currently visible at the USGS gage at Hancock.

Daily Flows:

Little Falls gage flow 2017-09-18: 1254 MGD (1940 cfs)

Little Falls gage flow 2017-09-19: 1280 MGD (est., based on recently available real time data) (1980 cfs)

Note: Gage flow at Little Falls is measured after water supply withdrawals.

Point of Rocks flow 2017-09-18: 1260 MGD (1950 cfs)

Point of Rocks flow 2017-09-19: 1306 MGD (est., based on recently available real time data) (2020 cfs)

Net Potomac Production (2017-09-18):

FW Corbalis raw water withdrawal (Potomac): 108 MGD

WSSC Potomac Production: 139 MGD

Aqueduct withdrawal: 149 MGD

Total Potomac demand: 396 MGD