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Virginia DEQ

Virginia Water Science Center

 
  Duration Plot and Table of 28-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 28-Day Average Streamflow Conditions
Provisional Data Subject to Revision 01646000 plot. DIFFICULT RUN NEAR GREAT FALLS, VA
Provisional Data Subject to Revision

                    

The current 28-day running-average value for 03/22/2017 is 32.04 cubic feet per second.

  explanation   Percentile Description Duration Plot Description 28 Day 14 Day 7 Day Daily
      Duration Table of 28-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
11.7
23.4
28.2
42.0
65.0
87.5
118
139
216
 
80
February
12.6
30.4
36.1
48.9
66.0
90.8
122
146
281
 
80
March
17.4
41.2
47.1
58.0
77.0
98.7
139
178
251
 
80
April
26.4
38.4
42.7
58.1
82.2
107
138
178
246
 
80
May
21.0
32.6
36.5
49.1
67.9
97.8
130
161
295
 
81
June
9.64
22.6
26.2
39.0
57.6
83.0
109
146
1,290
 
81
July
4.31
12.7
17.7
25.6
42.0
62.2
90.9
122
1,320
 
81
August
1.92
8.80
11.9
19.2
30.2
55.3
80.8
97.9
158
 
81
September
0.60
7.54
9.74
16.2
27.7
48.5
84.6
138
320
 
81
October
2.43
8.70
11.4
16.9
25.1
45.6
91.4
119
384
 
80
November
4.87
13.9
16.3
22.5
35.2
61.4
101
117
215
 
80
December
7.79
19.4
23.9
32.9
51.9
73.8
118
143
242
 
80
 
       

The current 28-day running-average value for 03/22/2017 is 32.04 cubic feet per second.

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

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