Monitoring Reports

Over the past 24 hours the Potomac basin has received between 0.1 and 1 inch of rain; isolated areas in the North Branch received higher amounts closer to 2 inches. The precipitation forecast shows accumulated rainfall estimates between 1.25 and 1.5 inches of rain across the basin over the next 48 hours. ICPRB CO-OP staff will make a determination about the need to continue daily monitoring based on the actual rainfall received and the resultant flow levels. A flow measurement has been taken at Point of Rocks and we are waiting for the rating curve to be revised.

Flow at Point of Rocks dropped below the daily monitoring threshold of 2,000 cfs last Friday. While demand is low right now and there is potential for significant rain in the forecast, daily monitoring has been initiated given that flows continued to drop over the weekend. The Point of Rocks flow is currently below the 25 percentile. The various precipitation forecasts show different accumulated rainfall estimates, but most predict between 1.75 and 2.5 inches of rain across the basin over the next 48 hours.

The e-mail report below concludes the 2011 CO-OP Drought Exercise. The exercise focused on use of our daily flow forecast tool and the newly updated OASIS model to inform decisions concerning reservoir releases. This fall we will be testing a variety of new operation procedures using our planning tools, PRRISM and OASIS, in conjunction with Hydrologic's WRF project on climate change. A brief after action report on this year's drought exercise will be forthcoming.

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A Little Seneca water supply release of 30 MGD (total target of 66 cfs) was requested 9/18/2015 and will continue until further notice. The Jennings Randolph release was increased to reflect a Luke target flow of 350 cfs (226 MGD).

(SIMULATED) Little Seneca and Jennings Randolph water supply releases continue. We will watch flows closely to determine the on-going need and magnitude of the releases.

There has been no significant rainfall in the basin over the past 24 hours. The National Weather Service quantitative precipitation
forecasts indicate that there will be accumulations of up to 0.75 inches over much of the basin during the next five days.

A Little Seneca water supply release of 30 MGD (total target of 66 MGD) was requested this morning and will continue until further notice
(SIMULATED). We will watch flows closely to determine the on-going need and magnitude of the release.

DROUGHT EXERCISE - Afternoon Potomac flow and demand update (Saturday 09/17/2011)

There has been no significant rainfall in the basin over the past 24 hours. The National Weather Service quantitative precipitation forecasts indicate that there will be accumulations of up to 0.75 inches over much of the basin during the next five days.

Yesterday, trace amounts of precipitation were seen in isolated spots in the basin. The 2-day forecast predicts 0.5 to 1.0 inch of precipitation over the entire basin. The 5-day forecast indicates a chance of 0.5 to 2.0 inches of precipitation may occur over the next couple of days.

Point of Rocks flow has well exceeded the low flow monitoring threshold for several days now. While flows are beginning to drop some, we believe that they may remain high for a little longer. Therefore, daily monitoring is discontinued, but may be re-initiated at any time.

Yesterday 0.10 to 0.50 inches of rain accumulated across much of the
basin. A limited area in the north received between 0.50 and 2.00
inches. The 2-day forecast predicts only trace precipitation over the
northern portion of the basin. The 5-day forecast indicates a chance
of up to 0.50 inches over the entire basin.

While Point of Rocks is still above the 2,000 cfs threshold, daily
monitoring remains active as only minor precipitation events are
predicted for the next couple of days.

Over the past 24 hours, the basin received between 0.10 and 3.0 inches of rain. The heaviest rain in the region fell outside of the basin to the south and north east. MARFC's 48-hour forecast shows a chance of a 0.25 of an inch of rain across most of the basin. The 5-day forecast shows that the basin could receive between 0.5 and 1.00 inch of rain.

Point of Rocks flow is currently above the 2,000 cfs threshold. We will track flows and the weather forecast to see if this is sustainable. Daily monitoring remains active.