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Virginia DEQ

Virginia Water Science Center

 
  Duration Plot and Table of Daily 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 2007.
REGULATION.--No known regulation.
GAGE OPERATION.--Virginia Department of Environmental Quality - Water Division.
     Duration Plot with Daily Streamflow Conditions
Provisional Data Subject to Revision 01646000 plot. DIFFICULT RUN NEAR GREAT FALLS, VA
Provisional Data Subject to Revision

                    

The current daily value for 08/28/2008 is 19 cubic feet per second.

  explanation   Percentile Description Duration Plot Description 28 Day 14 Day 7 Day Daily
      Duration Table of Daily 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
9.00
18.0
23.0
33.0
50.0
75.0
123
193
2,100
 
72
February
11.0
25.0
31.0
41.0
54.0
80.8
137
219
1,500
 
72
March
16.0
32.0
36.0
46.0
62.0
89.0
150
253
1,510
 
72
April
20.0
30.0
35.0
44.0
59.0
84.0
129
209
1,160
 
73
May
14.0
22.0
25.0
34.0
49.0
73.0
124
195
2,310
 
73
June
4.30
14.0
17.0
23.0
37.0
53.0
89.1
149
25,000
 
73
July
1.50
6.20
9.90
16.0
26.0
39.0
72.0
128
1,200
 
73
August
0.20
4.50
6.42
11.0
20.0
33.0
64.8
131
2,000
 
73
September
0.10
4.00
5.70
10.0
18.0
28.0
57.0
110
3,310
 
73
October
0.94
7.00
9.20
13.0
20.0
33.0
64.9
112
3,000
 
72
November
5.70
12.0
15.0
20.0
29.0
47.0
84.0
161
2,220
 
72
December
7.20
17.0
21.0
28.0
38.0
59.0
106
178
2,140
 
72
 
       
Instantaneous minimum flow for period of record = 0.05 cubic feet per second.

The current daily value for 08/28/2008 is 19 cubic feet per second.

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

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