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Flows

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Flows

The graphs below are created using an automated process. Each night, scripts retrieve data via the internet and process information to update the graphs. Disruptions to data feed, internet service, and other events beyond the control of DRBC could delay update of the graphs.


The animated water yield choropleth is developed by retrieving the daily mean discharge for USGS gages in the Delaware River basin for the previous several days, dividing each gage's discharge by it's drainage area, and computing the mean yield for each HUC8 watershed. Since this image is intended to demonstrate the watersheds' contribution toward flow in the mainstem Delaware River, mainstem gages are not included in the computation. River Mile is the distance in miles upstream from the line between the Cape May Light (New Jersey) and the tip of Cape Henlopen (Delaware), where Delaware Bay meets the Atlantic Ocean.

This graph shows a constructed profile (blue line) of Delaware River mean daily discharge (cubic feet per second) for the previous day using information from USGS gages. The profile reflects gages on the main stem Delaware as well as tributaries including the Neversink River (River Mile 253.6), Brodhead Creek (RM 213) , the Lehigh River (RM 183.7) and several others. The profile is plotted against a boxplot of location specific daily discharge values from the most recent 20 year period, and against the flow targets at Trenton and Montague. River Mile is the distance in miles upstream from the line between the Cape May Light (New Jersey) and the tip of Cape Henlopen (Delaware), where Delaware Bay meets the Atlantic Ocean.

This graph shows a constructed profile (blue line) of Schuylkill River mean daily discharge (cubic feet per second) for the previous day using information from USGS gages. The profile reflects gages on the main stem Schuylkill as well as tributaries including the Little Schuylkill, Tulpehocken Creek, Perkiomen Creek, Wissahickon Creek and other tributaries. The profile is plotted against a boxplot of location specific daily discharge values from the most recent 20 year period. Schuylkill River Mile is approximately the distance in miles upstream from the mouth of the Schuylkill River at its confluence with the Delaware River.

The animated water surface elevation plot retrieves the observed (red) and the predicted (blue) hourly water surface elevations from the previous 2 days through the next 2 days from all the NOAA PORTS stations in the Delaware Estuary, and knits them into a GIF animation. The animated version of this plot provides an intuitive demonstration of how tide propagates through the estuary. These observed and predicted values are plotted along with important water surface elevation thresholds for Lewes, DE, Reedy Island, DE, and Philadelphia, PA. The elevations are plotted relative to mean lower low water (MLLW) which is the average of the lower low water height of each tidal day for that specific location. Gray background shading indicates the quantiles of 6-minute water surface elevation observations from available data during the period from 2000 through 2020.

The above plot is an EXPERIMENTAL prediction of the salt front location. The model uses a LOESS smooth of paired observed daily salt front location and 18-day cumulative flow at the Delaware at Trenton + the Schuylkill at Philadelphia, lagged by 2 days during a period from 1997 through a portion of 2021. New predicted values use observed flow augmented by predicted flow provided by NOAA’s Advanced Hydrologic Prediction Service (AHPS). The plot includes the residual salt front locations from the 1997-2021 data set where historic hindcast salt front location predictions matched the daily prediction to within +\- 0.3 miles. This is added to illustrate variability at different salt front locations and differences in variability between high and low salt front location values.

R scripts developed by John Yagecic. HTML programming by Karl Heinicke. Questions, contact John.Yagecic@drbc.nj.gov