Warning: Javascript must be enabled to use all the features on this page!

Page Loading - Please Wait...

* We've detected you're using a mobile device. Find our Next Generation Station Page here.
Click to hideNews Bulletins
  • Notice of planned maintenance to underlying USGS network September 24-26, 2021: During this maintenance period users may experience intermittent periods of inaccessibility or delayed delivery of hydrologic data to the USGS National Water Information System (NWIS). Please email gs-w_support_nwisweb@usgs.gov with any concerns regarding impacts to data delivery.
  • Explore the NEW USGS National Water Dashboard interactive map to access real-time water data from over 13,500 stations nationwide.
  • Full News RSS icon

Water-Year Summary for Site 01648010

Click to hide Water-Year Summary instructions and information
  • Water-Year Summary reports summarize a year of hydrologic data in a printer-friendly format.
  • For water years 2014 onward, choose a water year and parameter and an on-demand Water-Year Summary report will be generated.
  • For water years 2006 through 2013, choose a water year and an Annual Water Data Report will be provided.
  • For water years 2005 and earlier, Annual Water Data Reports may be available in digital format.
  • Not all sites have reports available for every water year.
Available Parameters
00010 Temperature, water(Max.,Min.,Mean)  
00060 Discharge(Mean)  
00095 Specific cond at 25C(Max.,Min.,Mean)  
00300 Dissolved oxygen(Max.,Min.,Mean)  
00400 pH(Max.,Min.,Med.)  
63680 Turbidity, Form Neph(Min.,Max.,Mean)  
72254 Sensor velocity(Max.,Min.,Mean) [Discontinued]  
72254 Sensor velocity(Max.,Min.,Mean) [Discontinued]  
99133 NO3+NO2,water,insitu(Max.,Min.,Mean) [Discontinued]  

Water year 2021: 2021-10-01 to 2022-09-30

Print this page
USGS Water-Year Summary 2021
LOCATION - Lat 38°57'36.6", long 77°02'31.4" referenced to North American Datum of 1983, Washington, DC, Hydrologic Unit 02070010, on right bank at downstream side of bridge on Joyce Road.
DRAINAGE AREA - 63.7 mi².
PERIOD OF RECORD - April 2007 to September 2012 (gage heights and discharge measurements only). October 2012 to current year.
GAGE - Water stage recorder and crest-stage gage. Datum of gage is 136.78 ft above North American Vertical Datum of 1988.
  • Water Year 2020: Records good, except those above 2,000 ft³/s, which are poor.
  • Water Years 2017-2019: Records good, except those above 2,000 ft³/s and those for estimated discharges, which are poor.
  • Water Year 2016: Records good, except those above 2,000 ft³/s and those for estimated daily discharges, which are poor.
  • Water Years 2014-2015: Records good, except those for estimated daily discharges, which are poor.
  • Water Year 2013 and prior years’ accuracy statements can be found in Annual Water Data Reports.

  • Flow affected by two upstream reservoirs which control flow from about 25 mi², Needwood Lake on Rock Creek since Sept. 1966 and Bernard Frank Lake on North Branch Rock Creek since February 1968. U.S. Geological Survey water-data telemeter at station.
    PERIOD OF DAILY RECORD - WATER TEMPERATURE: June 2012 to current year. SPECIFIC CONDUCTANCE: June 2012 to current year. DISSOLVED OXYGEN: June 2012 to current year. pH: June 2012 to current year. TURBIDITY: June 2012 to current year. CDOM: December 2015 to current year. NITRATE: November 2015 to current year.
    COOPERATION - Funding for water-quality data collection is provided by the Montgomery County Department of Environmental Protection and the U.S. Geological Survey.
    INSTRUMENTATION - Water-quality monitor: 06/2012 to 10/01/2014: YSI 6920V2 10/01/2014 to present: YSI EXO2
    REMARKS - For Water Year 2014, Turbidity values greater than 1,000 formazin nepthelometric units (FNU) exceed the instrument calibration range. Values are included in the record but are presumed to have lower precision. For Water Year 2015, instrumentation changes allow for more precise readings to 4,000 FNU. Any values that exceed 4,000 FNU are excluded from the record. Missing record due to periodic instrument malfunction.

    SPECIFIC CONDUCTANCE: Maximum, 9,020 microsiemens per centimeter, February 23, 2015; minimum, 10 microsiemens per centimeter, Oct. 30, 2012.

    WATER TEMPERATURE: Maximum, 29.6°C, on many days, first occurrence on July 21, 2019; minimum, -0.1°C, on many days, first occurrence on Dec. 28, 2017. 

    pH: Maximum, 11.8 standard units, December 13, 2013; minimum, 5.7 standard units, June 27, 2015.

    TURBIDITY: Maximum, 1,500 formazin nephelometric units (FNU), April 20, 2015; minimum, 0.0 formazin nephelometric units (FNU), on several days.

    DISSOLVED OXYGEN: Maximum, 16.2 milligrams per liter, March 27, 2014; minimum, 3.19 milligrams per liter, July 18, 2017.

    NITRATE:  Maximum 1.94 milligrams per liter, on many days, first occurrence on Feb. 07, 2019; minimum 0.15 milligrams per liter, on many days, first occurrence on Nov. 06, 2018. 

    MEAN VELOCITY FROM 1500kHz ACOUSTIC UNIT: Maximum, 5.58 feet per second, May 3, 2016; minimum, -0.04 feet per second, on September 6&9, 2015.

    MEAN VELOCITY FROM 3000kHz ACOUSTIC UNIT: Maximum, 4.63 feet per second, May 3, 2016; minimum,-0.15 feet per second, on January 4, 2016.