Monitoring Updates

Current drought monitoring status: Not Active (as of 10/17/14)


Daily Potomac flow and demand update (Friday 10/17/2014)

Daily flow and demand monitoring is discontinued now that flow at the Point of Rocks gage has risen well above 2,000 cfs.

Thank you to everyone who provided daily reports.

Daily Flows:

        Little Falls gage flow 10/16: 4000 MGD  (6190 cfs)

        Little Falls gage flow 10/17: 5260 MGD (est., based on recently available real time data)  (8140 cfs)

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

        Point of Rocks flow 10/16: 3330 MGD (5150 cfs)

        Point of Rocks flow 10/17: 6120 MGD (est., based on recently available real time data) (9470 cfs)


Daily Potomac flow and demand update (Thursday 10/16/2014)

​Point of Rocks flow is currently at 4,140 cfs and is above the low flow threshold of 2,000 cfs. Bear with us while we wait to see if Point of Rocks flow remains above the low-flow threshold of 2,000 cfs.

The National Weather Service reports that yesterday between 0.5 and 2.0 inches of rain fell over the basin. The 72-hour forecast shows between 0.1 and 0.25 inches of rain may fall in the basin. The 7-day forecast shows that between 0.1 and 0.6 inches of rain may fall in the basin.

Daily Flows:

        Little Falls gage flow 10/15: 1810 MGD  (2800 cfs)

        Little Falls gage flow 10/16: 3030 MGD (est., based on recently available real time data)  (4680 cfs)

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

        Point of Rocks flow 10/15: 1590 MGD (2460 cfs)

        Point of Rocks flow 10/16: 2680 MGD (est., based on recently available real time data) (4140 cfs)

Net Potomac Production (10/15/14):

        FW Corbalis raw water withdrawal (Potomac): 72 MGD

        WSSC Potomac Production: 117 MGD

        Aqueduct withdrawal: 138 MGD

        Total Potomac demand: 327 MGD


Daily Potomac flow and demand update (Wednesday 10/15/2014)

During the past 24 hours the western half of the basin received 1 to 2 inches of rain. More rain is on the way, with forecasted accumulations of 1 to 2 inches across the basin over the next two days. Given the forecast and recent rainfall, we expect that mean daily flow at Point of Rocks will soon rise above the trigger for daily drought monitoring of 2000 cfs.

 

Daily Flows:

        Little Falls gage flow 10/14: 1500 MGD  (2320 cfs)

        Little Falls gage flow 10/15: 1520 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 10/14: 1220 MGD (1880 cfs)

        Point of Rocks flow 10/15: 1290 MGD (est., based on recently available real time data) (2000 cfs)

Net Potomac Production (10/14/14):

        FW Corbalis raw water withdrawal (Potomac): 64 MGD

        WSSC Potomac Production: 113 MGD

        Aqueduct withdrawal: 136 MGD

        Total Potomac demand: 313 MGD


Daily Potomac flow and demand update (Tuesday 10/14/2014)

The National Weather Service reports that yesterday between 0.1 and 0.5 inches of rain fell over much of the basin. The 48-hour forecast is showing significant rainfall, with accumulated totals between. 1.0 and 2.0 inches across the basin.

Daily Flows:

        Little Falls gage flow 10/13: 1430 MGD  (2210 cfs)

        Little Falls gage flow 10/14: 1490 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 10/13: 1200 MGD (1860 cfs)

        Point of Rocks flow 10/14: 1290 MGD (est., based on recently available real time data) (2000 cfs)

Net Potomac Production (10/13/14):

        FW Corbalis raw water withdrawal (Potomac): 81 MGD

        WSSC Potomac Production: 125 MGD

        Aqueduct withdrawal: 131 MGD

        Total Potomac demand: 337 MGD


Daily Potomac flow and demand update (Monday 10/13/2014)

Trace amounts of rain fell across much of the basin over the last 24 hours.  Some areas received up to a quarter of an inch of rain.  The Middle Atlantic River Forecast Center predicts that one to one and three quarters inches of rain may fall across the basin in the next 72 hours.  

Daily Flows:

        Little Falls gage flow 10/12: 1420 MGD  (2190 cfs)

        Little Falls gage flow 10/13: 1400 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 10/12: 1180 MGD (1820 cfs)

        Point of Rocks flow 10/13: 1220 MGD (est., based on recently available real time data) (1890 cfs)

Net Potomac Production (10/12/14):

        FW Corbalis raw water withdrawal (Potomac): 59 MGD

        WSSC Potomac Production: 116 MGD

        Aqueduct withdrawal: 122 MGD

        Total Potomac demand: 297 MGD


Daily Potomac flow and demand update (Sunday 10/12/2014)

The Potomac basin received 0 to 1/4 of an inch of rain over the past 24 hours. The National Weather Service's 3-day forecast calls for total accumulations of 1/10 to 3/4 inch in the basin, with most areas expecting to receive 1/4 to 1/2 inch of rain..

Flow at Point of Rocks remains below the low-flow threshold of 2,000 cfs. Flow at Point or Rocks continues to rise, but is still below median levels for this time of the year.

Daily Flows:

        Little Falls gage flow 10/11: 1380 MGD  (2130 cfs)

        Little Falls gage flow 10/12: 1430 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 10/11: 1100 MGD (1700 cfs)

        Point of Rocks flow 10/12: 1220 MGD (est., based on recently available real time data) (1890 cfs)

Net Potomac Production (10/11/14):

        FW Corbalis raw water withdrawal (Potomac): 71 MGD

        WSSC Potomac Production: 110 MGD

        Aqueduct withdrawal: 122 MGD

        Total Potomac demand: 303 MGD


Daily Potomac flow and demand update (Saturday 10/11/2014)

The Potomac basin received 1/4 to 3/4 of an inch of rain over the past 24 hours, and 1/2 to 1 1/2 inches over the past 5 days. Flows throughout the basin continue to rise, but are still below median levels for this time of the year in many areas. The National Weather Service's 3-day forecast calls for total accumulations of 1/4 to 1/2 inch in most parts of the basin.

Daily Flows:

        Little Falls gage flow 10/10: 1220 MGD  (1880 cfs)

        Little Falls gage flow 10/11: 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 10/10: 1030 MGD (1590 cfs)

        Point of Rocks flow 10/11: 1120 MGD (est., based on recently available real time data) (1740 cfs)

Net Potomac Production (10/10/14):

        FW Corbalis raw water withdrawal (Potomac): 83 MGD

        WSSC Potomac Production: 108 MGD

        Aqueduct withdrawal: 126 MGD

        Total Potomac demand: 317 MGD


Daily Potomac flow and demand update (Friday 10/10/2014)

Yesterday, an isolated area of the basin received trace amounts of precipitation. The National Weather Service forecasts 1/4 of an inch of rain over the entire basin over the next 24 hours. Accumulations over the next 3 days could reach between 1/2 and 1 inch.

Daily Flows:

        Little Falls gage flow 10/09: 1270 MGD  (1960 cfs)

        Little Falls gage flow 10/10: 1200 MGD (est., based on recently available real time data)  (1850 cfs)

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

        Point of Rocks flow 10/09: 1020 MGD (1580 cfs)

        Point of Rocks flow 10/10: 1020 MGD (est., based on recently available real time data) (1580 cfs)

Net Potomac Production (10/09/14):

        FW Corbalis raw water withdrawal (Potomac): 88 MGD

        WSSC Potomac Production: 115 MGD

        Aqueduct withdrawal: 130 MGD

        Total Potomac demand: 333 MGD


Daily Potomac flow and demand update (Thursday 10/09/2014)

There was no precipitation in the basin over the past 24 hours according to the National Weather Service.  Precipitation ranging from one quarter of an inch to one inch is expected across the basin over the next 72 hours according to the Middle Atlantic River Forecast Center. The largest rainfall totals are expected in the central portion of the basin.  

Daily Flows:

    Little Falls gage flow 10/08: 1435 MGD  (2220 cfs)

    Little Falls gage flow 10/09: 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 10/08: 1015 MGD (1570 cfs)

    Point of Rocks flow 10/09: 1034 MGD (est., based on recently available real time data) (1600 cfs)

Net Potomac Production (10/08/14):

    FW Corbalis raw water withdrawal (Potomac): 87 MGD

    WSSC Potomac Production: 94 MGD

    Aqueduct withdrawal: 131 MGD

    Total Potomac demand: 312 MGD


Daily Potomac flow and demand update ( Wednesday 10/08/2014)

Flow at Point of Rocks continues to be below the low-flow threshold of 2,000 cfs. Significant precipitation fell over the basin over the past 24 hours, with accumulations of 1/10 to 1/2 inch, and as much as an inch in a few areas. The National Weather Service's 72-hour quantitative precipitation forecast (QPF) calls for 1/4 to 1 inch in the over the next few days.

Daily Flows:

        Little Falls gage flow 10/07: 1390 MGD  (2150 cfs)

        Little Falls gage flow 10/08: 1400 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 10/07: 1000 MGD (1540 cfs)

        Point of Rocks flow 10/08: 1010 MGD (est., based on recently available real time data) (1560 cfs)

Net Potomac Production (10/07/14):

        FW Corbalis raw water withdrawal (Potomac): 71 MGD

        WSSC Potomac Production: 122 MGD

        Aqueduct withdrawal: 145 MGD

        Total Potomac demand: 338 MGD


Daily Potomac flow and demand update (Tuesday 10/07/2014)

Significant precipitation fell over the northwestern half of the basin over the past 24 hours, with accumulations of 1/10 to 1/2 inch, and over an inch in a few areas. The National Weather Service's 72-hour quantitative precipitation forecast (QPF) calls for 1/4 to 1/2 inch in the northwestern portion of the basin over the next few days.

Daily Flows:

        Little Falls gage flow 10/06: 1570 MGD  (2430 cfs)

        Little Falls gage flow 10/07: 1370 MGD (est., based on recently available real time data)  (2120 cfs)

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

        Point of Rocks flow 10/06: 1040 MGD (1610 cfs)

        Point of Rocks flow 10/07: 1030 MGD (est., based on recently available real time data) (1600 cfs)

Net Potomac Production (10/06/14):

        FW Corbalis raw water withdrawal (Potomac): 100 MGD

        WSSC Potomac Production: 118 MGD

        Aqueduct withdrawal: 145 MGD

        Total Potomac demand: 363 MGD


Daily Potomac flow and demand update (Monday 10/06/2014)

The National Weather Service reports that the majority of the basin received zero inches of rain over the last 24-hour period. A few small areas of the basin received trace amounts of rain in the last 24-hour period. The Middle Atlantic River Forecast Center predicts that there may be 0.1 to 1 inch of rain in the 72-hour period and the National Weather Service predicts that there may be 0.25 to 1.75 inches of rain in the 7-day period.

Daily Flows:

        Little Falls gage flow 10/05: 1860 MGD  (2880 cfs)

        Little Falls gage flow 10/06: 1580 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 10/05: 1110 MGD (1710 cfs)

        Point of Rocks flow 10/06: 1070 MGD (est., based on recently available real time data) (1660 cfs)

Net Potomac Production (10/05/14):

        FW Corbalis raw water withdrawal (Potomac): 86 MGD

        WSSC Potomac Production: 111 MGD

        Aqueduct withdrawal: 127 MGD

        Total Potomac demand: 324 MGD


Daily Potomac flow and demand update (Sunday 10/05/2014)

Flows are elevated at Little Falls because of the Artificially Varied Flow (AVF) release from Jennings Randolph that occurred on the 27th and 28th of September.

Trace amounts to a quarter of an inch of rain fell in small, isolated areas in the central portion of the basin over the past 24 hours according to the National Weather Service.  The Middle Atlantic River Forecast Center predicts one quarter to one half of an inch of rain over the next 72 hours, with the largest amounts expected in the far western parts of the basin.

Daily Flows:

        Little Falls gage flow 10/04: 1590 MGD  (2460 cfs)

        Little Falls gage flow 10/05: 1840 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 10/04: 1270 MGD (1960 cfs)

        Point of Rocks flow 10/05: 1160 MGD (est., based on recently available real time data) (1800 cfs)

Net Potomac Production (10/04/14):

        FW Corbalis raw water withdrawal (Potomac): 88 MGD

        WSSC Potomac Production: 105 MGD

        Aqueduct withdrawal: 130 MGD

        Total Potomac demand: 323 MGD


Daily Potomac flow and demand update (Saturday 10/04/2014)

The National Weather Service reports that 0.1 to 1.5 inches of rain fell in the basin in the last 24-hour period. A few small areas of the basin received as much as 1.75 inches of rain in the last 24-hour period. There is 0 to 0.5 inches of rain in the 72-hour forecast. The 7-day forecast indicates accumulations between 0.1 and 1.5 inches of rain possible across the basin.

Point of Rocks flows are currently above the low-flow threshold of 2,000 cfs. We will continue daily monitoring until data shows that flows will likely stay above this threshold for some time.

Daily Flows:

    Little Falls gage flow 10/03: 1610 MGD  (2490 cfs)

    Little Falls gage flow 10/04: 1490 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 10/03: 1270 MGD (1960 cfs)

    Point of Rocks flow 10/04: 1330 MGD (est., based on recently available real time data) (2050 cfs)

Net Potomac Production (10/03/14):

    FW Corbalis raw water withdrawal (Potomac): 96 MGD

    WSSC Potomac Production: 124 MGD

    Aqueduct withdrawal: 138 MGD

    Total Potomac demand: 358 MGD


Daily Potomac flow and demand update (Friday 10/03/2014)

The National Weather Service reports that no rain fell in the basin in the last 24-hour period. There is a chance of 1/4 to 1/2 an inch of rain in the 24-hour forecast. The 7-day forecast indicates accumulations between 3/4 and 1 inch of rain is possible across the basin.

The Artificially Varied Flow (AVF) release from the North Branch reservoirs reached the Point of Rocks gage yesterday. Flow is currently just above 2,000 cfs, but we expect it to fall again unless it rains in the area.

Daily monitoring will continue over the weekend.

Daily Flows:

        Little Falls gage flow 10/02: 1320 MGD  (2040 cfs)

        Little Falls gage flow 10/03: 1650 MGD (est., based on recently available real time data)  (2550 cfs)

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

        Point of Rocks flow 10/02: 1490 MGD (2300 cfs)

        Point of Rocks flow 10/03: 1330 MGD (est., based on recently available real time data) (2050 cfs)

Net Potomac Production (10/02/14):

        FW Corbalis raw water withdrawal (Potomac): 89 MGD

        WSSC Potomac Production: 108 MGD

        Aqueduct withdrawal: 149 MGD

        Total Potomac demand: 346 MGD


Daily Potomac flow and demand update (Thursday 10/02/2014) 

Only trace amounts of rain fell over the Potomac basin over the past 24 hours. The Middle Atlantic River Forecast Center predicts accumulations of 1/10 to 1/2 inch in the basin over the next 72 hours. Potomac River flow at Point of Rocks is beginning to rise due to the USACE's Sep 27-28 Artificially Varied Flow (AVF) release from the North Branch reservoirs.

Daily Flows:

        Little Falls gage flow 10/01: 1200 MGD  (1850 cfs)

        Little Falls gage flow 10/02: 1250 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 10/01: 1070 MGD (1650 cfs)

        Point of Rocks flow 10/02: 1440 MGD (est., based on recently available real time data) (2230 cfs)

Net Potomac Production (10/01/14):

        FW Corbalis raw water withdrawal (Potomac): 88 MGD

        WSSC Potomac Production: 119 MGD

        Aqueduct withdrawal: 137 MGD

        Total Potomac demand: 344 MGD


Daily Potomac flow and demand update (Wednesday 10/01/2014)

The National Weather Service reports that rain fell across the entire basin over the last 24 hours. Accumulation totals range from trace amounts to 1.25 inches. There may be an additional accumulation of trace amounts today. The 72-hour forecast indicates the basin may receive between one- and three-quarters of an inch of rain.

Daily Flows:

        Little Falls gage flow 09/30: 1110 MGD  (1710 cfs)

        Little Falls gage flow 10/01: 1110 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 09/30: 960 MGD (1490 cfs)

        Point of Rocks flow 10/01: 1000 MGD (est., based on recently available real time data) (1540 cfs)

Net Potomac Production (09/30/14):

        FW Corbalis raw water withdrawal (Potomac): 90 MGD

        WSSC Potomac Production: 117 MGD

        Aqueduct withdrawal: 153 MGD

        Total Potomac demand: 360 MGD


Daily Potomac flow and demand update (Tuesday 09/30/2014)

Only trace amounts of precipitation fell in the Potomac basin over the past 24 hours. The Middle Atlantic River Forecast Center forecasts accumulations ranging from 0 to 3/4 inches in the basin over the next 72 hours. The National Weather Service's Weather Prediction Center forecasts over an inch of rain in the western portion of the basin over the next 5 days.

Daily Flows:

        Little Falls gage flow 09/29: 1150 MGD  (1780 cfs)

        Little Falls gage flow 09/30: 1110 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 09/29: 980 MGD (1520 cfs)

        Point of Rocks flow 09/30: 970 MGD (est., based on recently available real time data) (1500 cfs)

Net Potomac Production (09/29/14):

        FW Corbalis raw water withdrawal (Potomac): 110 MGD

        WSSC Potomac Production: 114 MGD

        Aqueduct withdrawal: 136 MGD

        Total Potomac demand: 360 MGD


Daily Potomac flow and demand update (Monday 09/29/2014)

The National Weather Service reports that 0 to a 0.25 inch of rain fell across the basin over the last 24 hours. The Middle Atlantic River Forecast Center predicts 0 to a 0.25 inch of rain over the next 72 hours, and the and the National Weather Service predicts 0.1 to 1 inch of rain over the 7 days.

Daily Flows:

        Little Falls gage flow 09/28: 1270 MGD  (1970 cfs)

        Little Falls gage flow 09/29: 1110 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 09/28: 1010 MGD (1570 cfs)

        Point of Rocks flow 09/29: 970 MGD (est., based on recently available real time data) (1500 cfs)

Net Potomac Production (09/28/14):

        FW Corbalis raw water withdrawal (Potomac): 98 MGD

        WSSC Potomac Production: 126 MGD

        Aqueduct withdrawal: 133 MGD

        Total Potomac demand: 357 MGD


Daily Potomac flow and demand update (Sunday 09/28/2014)

The National Weather Service reports that trace amounts of rain fell in small, isolated areas of the basin over the last 24 hours. Their 48-hour forecast shows no rain in the basin. Trace amounts may fall in the western portion of the basin over the next five days.  

A scheduled artificially varied flow release of 1,000 cfs from Jennings Randolph Reservoir began yesterday at 10 am and will end today at 4 pm.

Daily Flows:

        Little Falls gage flow 09/27: 1310 MGD  (2020 cfs)

        Little Falls gage flow 09/28: 1250 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 09/27: 1090 MGD (1680 cfs)

        Point of Rocks flow 09/28: 1010 MGD (est., based on recently available real time data) (1560 cfs)

Net Potomac Production (09/27/14):

        FW Corbalis raw water withdrawal (Potomac): 83 MGD

        WSSC Potomac Production: 117 MGD

        Aqueduct withdrawal: 128 MGD

        Total Potomac demand: 328 MGD


Daily Potomac flow and demand update (Saturday 09/27/2014)

No rain fell in the basin over the past 24 hours according to the National Weather Service.  The Middle Atlantic River Forecast Center predicts up to half an inch of rain over the next 72 hours, with the largest amounts expected in the southeastern portions of the basin.

Daily Flows:

        Little Falls gage flow 09/26: 1340 MGD  (2070 cfs)

        Little Falls gage flow 09/27: 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 09/26: 1080 MGD (1670 cfs)

        Point of Rocks flow 09/27: 1100 MGD (est., based on recently available real time data) (1700 cfs)

Net Potomac Production (09/26/14):

        FW Corbalis raw water withdrawal (Potomac): 90 MGD

        WSSC Potomac Production: 118 MGD

        Aqueduct withdrawal: 139 MGD

        Total Potomac demand: 347 MGD


Daily Potomac flow and demand update (Friday 09/26/2014)

Over the past 24 hours, one quarter to three quarters of an inch of rain fell across much of the basin according to the National Weather Service.  The Middle Atlantic River Forecast Center predicts no rainfall in the Potomac basin over the next 72 hours.

Daily Flows:

        Little Falls gage flow 09/25: 1390 MGD  (2150 cfs)

        Little Falls gage flow 09/26: 1430 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 09/25: 1010 MGD (1570 cfs)

        Point of Rocks flow 09/26: 1050 MGD (est., based on recently available real time data) (1620 cfs)

Net Potomac Production (09/25/14):

        FW Corbalis raw water withdrawal (Potomac): 74 MGD

        WSSC Potomac Production: 100 MGD

        Aqueduct withdrawal: 139 MGD

        Total Potomac demand: 313 MGD


Daily Potomac flow and demand update (Thursday 09/25/2014)

It is currently raining in the Potomac basin with 0 to 1 inch of accumulation over the past 24 hours. The Middle Atlantic River Forecast Center predicts 0 to 0.5 an inch of rain over the next 72 hours, and the and the National Weather Service predicts 0 to 0.5 an inch of rain over the 7 days.

Daily Flows:

        Little Falls gage flow 09/24: 1010 MGD  (1570 cfs)

        Little Falls gage flow 09/25: 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 09/24: 960 MGD (1490 cfs)

        Point of Rocks flow 09/25: 930 MGD (est., based on recently available real time data) (1440 cfs)

Net Potomac Production (09/24/14):

        FW Corbalis raw water withdrawal (Potomac): 103 MGD

        WSSC Potomac Production: 116 MGD

        Aqueduct withdrawal: 142 MGD

        Total Potomac demand: 361 MGD


Daily Potomac flow and demand update (Wednesday 09/24/2014)

Over the last 24 hours up to half an inch of rain fell around and upstream of the metro area. The National Weather Service indicates a chance of rain across the entire basin over the next 24 hours. The western areas can expect between trace amounts and half an inch. The predicted totals increase to the east, with up to 1.25 inches expected in the metro area. There is also a chance of a small amount of additional rain on Thursday.

Daily Flows:

        Little Falls gage flow 09/23: 1020 MGD  (1580 cfs)

        Little Falls gage flow 09/24: 1010 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 09/23: 1000 MGD (1540 cfs)

        Point of Rocks flow 09/24: 940 MGD (est., based on recently available real time data) (1460 cfs)

Net Potomac Production (09/23/14):

        FW Corbalis raw water withdrawal (Potomac): 102 MGD

        WSSC Potomac Production: 112 MGD

        Aqueduct withdrawal: 146 MGD

        Total Potomac demand: 360 MGD


Daily Potomac flow and demand update (Tuesday 09/23/2014)

Over the last 24 hours 0.1 to 0.75 inches of rain fell in the central portion of the basin, with the most falling along the border between Fairfax and Prince William counties. The National Weather Service indicates a chance of rain across the basin beginning Wednesday night through Thursday afternoon. Total rainfall amounts are predicted between 0.1 and 1.0 inch. The heaviest rainfall is forecast in the metro area and areas to the east.

Daily Flows:

        Little Falls gage flow 09/22: 1030 MGD  (1600 cfs)

        Little Falls gage flow 09/23: 1010 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 09/22: 1030 MGD (1600 cfs)

        Point of Rocks flow 09/23: 980 MGD (est., based on recently available real time data) (1520 cfs)

Net Potomac Production (09/22/14):

        FW Corbalis raw water withdrawal (Potomac): 120 MGD

        WSSC Potomac Production: 128 MGD

        Aqueduct withdrawal: 152 MGD

        Total Potomac demand: 400 MGD


Daily Potomac flow and demand update (Monday 09/22/2014)

Scattered rain, ranging from trace amounts to almost half an inch, occurred in localized portions of the basin over the last 24 hours according to the National Weather Service. The Middle Atlantic River Forecast Center predicts that less than 0.1 inch of rain may fall in a small area of the far western portion of the basin over the next 72 hours.  No precipitation is expected across the rest of the basin during that period.

Daily Flows:

        Little Falls gage flow 09/21: 1100 MGD  (1700 cfs)

        Little Falls gage flow 09/22: 1030 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 09/21: 1050 MGD (1630 cfs)

        Point of Rocks flow 09/22: 1030 MGD (est., based on recently available real time data) (1600 cfs)

Net Potomac Production (09/21/14):

        FW Corbalis raw water withdrawal (Potomac): 107 MGD

        WSSC Potomac Production: 125 MGD

        Aqueduct withdrawal: 138 MGD

        Total Potomac demand: 370 MGD


Daily Potomac flow and demand update (Sunday 09/21/2014)

Trace amounts of rain fell in a limited area between the USGS gage at Point of Rocks, MD and Washington, D.C. over the last 24 hours. The National Weather Service indicates there is a chance of 0.03 to 0.10 inches of rain over the next 72 hours and 0 to 0.5 inches over the next 7 days.

Thank you again to those sending in weekend daily withdrawal numbers.

Daily Flows:

        Little Falls gage flow 09/20: 1130 MGD  (1750 cfs)

        Little Falls gage flow 09/21: 1090 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 09/20: 1070 MGD (1660 cfs)

        Point of Rocks flow 09/21: 1050 MGD (est., based on recently available real time data) (1620 cfs)

Net Potomac Production (09/20/14):

        FW Corbalis raw water withdrawal (Potomac): 110 MGD

        WSSC Potomac Production: 121 MGD

        Aqueduct withdrawal: 136 MGD

        Total Potomac demand: 367 MGD


Daily Potomac flow and demand update (Saturday 09/20/2014)

​No rain fell in the basin over the last 24 hours. The National Weather Service indicates that there is a chance of trace rainfall over the next 72 hours and 0.1 to 0.5 inches distributed around the basin over the next 7 days.

Thank you to those sending in weekend daily withdrawal numbers. Please continue to send them to coop@icprb.org by 8 am on Sunday.

Daily Flows:

        Little Falls gage flow 09/19: 1160 MGD  (1790 cfs)

        Little Falls gage flow 09/20: 1090 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 09/19: 1100 MGD (1700 cfs)

        Point of Rocks flow 09/20: 1060 MGD (est., based on recently available real time data) (1640 cfs)

Net Potomac Production (09/19/14):

        FW Corbalis raw water withdrawal (Potomac): 108 MGD

        WSSC Potomac Production: 118 MGD

        Aqueduct withdrawal: 138 MGD

        Total Potomac demand: 364 MGD


Daily Potomac flow and demand update (Friday 09/19/2014)

A negligible amount of rain fell in limited areas over the last 24 hours. The National Weather Service indicates there is a chance of trace rainfall over the next 72 hours and up to 0.1 inches total over the next 7 days across much of the basin.

We will continue daily monitoring over the weekend. If you are responsible for sending us daily withdrawals, please send them to coop@icprb.org by 8am on both Saturday and Sunday. Thank you!

Daily Flows:

        Little Falls gage flow 09/18: 1160 MGD  (1790 cfs)

        Little Falls gage flow 09/19: 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 09/18: 1120 MGD (1730 cfs)

        Point of Rocks flow 09/19: 1070 MGD (est., based on recently available real time data) (1660 cfs)

Net Potomac Production (09/18/14):

        FW Corbalis raw water withdrawal (Potomac): 110 MGD

        WSSC Potomac Production: 121 MGD

        Aqueduct withdrawal: 151 MGD

        Total Potomac demand: 382 MGD


Daily Potomac flow and demand update (Thursday 09/18/2014)

Flow at Point of Rocks is currently 1780 cfs, which is below CO-OP's low-flow monitoring threshold of 2,000 cfs. The rating curve at Point of Rocks was changed on Tuesday by the USGS to more accurately reflect channel conditions, and reported flows over the past several weeks were adjusted downward.

Dry conditions are expected to persist at least over the short term. The Middle Atlantic River Forecast Center predicts negligible rainfall in the Potomac basin over the next 72 hours and the National Weather Service forecasts accumulations of only 1/10 inch across most of the basin over the next 7 days.

Thanks to those of you who provided us with recent demand data, and thank you for your ongoing cooperation.

Daily Flows:

Little Falls gage flow 09/17: 1230 MGD  (1900 cfs)

        Little Falls gage flow 09/18: 1200 MGD (est., based on recently available real time data)  (1850

cfs)

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

        Point of Rocks flow 09/17: 1150 MGD (1780 cfs)

        Point of Rocks flow 09/18: 1110 MGD (est., based on recently available real time data) (1720 cfs)

Net Potomac Production (09/17/14):

        FW Corbalis raw water withdrawal (Potomac): 103 MGD

        WSSC Potomac Production: 125 MGD

        Aqueduct withdrawal: 135 MGD

        Total Potomac demand: 363 MGD