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Virginia DEQ

Virginia Water Science Center

 
  Duration Plot and Table of 14-Day Average Streamflow
 
01646000 DIFFICULT RUN NEAR GREAT FALLS, VA
LOCATION.--Latitude 38°58'33", Longitude 77°14'46", North American Datum of 1927,
                    Fairfax County, VA, Hydrologic Unit 02070008.
DRAINAGE AREA.--57.8 square miles.
PERIOD OF RECORD.--October 1934 to current year. Monthly discharge only October to December 1934, published in WSP 1302.
DURATION STATISTIC COMPUTATION PERIOD.--All data through September 2015.
REGULATION.--No known regulation.
GAGE OPERATION.--Virginia Department of Environmental Quality - Water Division.
     Duration Plot with 14-Day Average Streamflow Conditions
Provisional Data Subject to Revision 01646000 plot. DIFFICULT RUN NEAR GREAT FALLS, VA
Provisional Data Subject to Revision

                    

The current 14-day running-average value for 03/22/2017 is 40.71 cubic feet per second.

  explanation   Percentile Description Duration Plot Description 28 Day 14 Day 7 Day Daily
      Duration Table of 14-Day Average Streamflow
            Flow values in cubic feet per second


                01646000     DIFFICULT RUN NEAR GREAT FALLS, VA

   Minimum daily flow
   5th percentile
 
   10th percentile
 
   25th percentile
 
 
   Median
 
 
   75th percentile
 
 
 
   90th percentile
 
 
 
   95th percentile
 
 
 
 
   Maximum daily flow
         
Years of record
January
12.0
20.4
26.4
38.2
60.3
89.1
128
151
330
 
80
February
12.7
28.6
34.5
46.1
62.7
91.9
134
170
396
 
80
March
16.6
36.6
42.9
54.7
75.7
106
149
181
385
 
80
April
23.1
34.5
39.8
50.9
73.4
107
151
176
362
 
80
May
16.8
27.4
32.4
42.8
63.1
89.3
142
172
351
 
81
June
7.09
18.0
21.9
32.2
50.5
72.7
116
149
2,530
 
81
July
2.29
10.3
13.7
22.3
34.2
57.9
96.7
124
2,570
 
81
August
0.71
6.78
9.74
16.4
27.1
46.9
88.2
118
283
 
81
September
0.20
5.78
8.10
13.4
22.8
40.8
91.6
129
591
 
81
October
1.00
7.77
10.8
15.9
23.8
43.1
83.9
149
611
 
80
November
5.34
13.3
16.4
23.1
35.1
65.2
101
139
297
 
80
December
8.06
19.4
23.9
32.2
49.7
80.0
119
160
326
 
80
 
       

The current 14-day running-average value for 03/22/2017 is 40.71 cubic feet per second.

---- Provisional Data Subject to Revision ----

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