ROANOKE RIVER BASIN

02056000  ROANOKE RIVER AT NIAGARA, VA

LOCATION.--Lat 37 degrees 15'18", long 79 degrees 52'18", Roanoke County, Hydrologic Unit 03010101, on right bank 200 ft downstream 
  from powerplant of Appalachian Power Company at Niagara, 2 mi downstream from Tinker Creek, 2.1 mi southeast of 
  Vinton, and at mile 355.3.

DRAINAGE AREA.--512 mi2.

PERIOD OF RECORD.--July 1926 to current year.

REVISED RECORDS.--WSP 972:  1927(M), 1929(M), 1934(M), 1937(M).  WSP 1303:  1928, 1930, 1933-38, 1940.  WSP 
  2104:   Drainage area.  WDR VA-72-1:  1928(M), 1930(M), 1933(M), 1935-36(M), 1938(M), 1940, 1944-45(M), 1948-
  49(M),   1951(M), 1955(M), 1960(M), 1967(M), 1969(M).

GAGE.--Water-stage recorder.  Datum of gage is 820.15 ft above sea level (levels by U.S. Army Corps of Engineers).

REMARKS.--Records good except those for periods with ice effect, Dec. 12-13, Jan. 8-12, and Feb. 2-6, which are 
  poor.  Flow regulated by dam and powerplant 200 ft upstream from station.  Maximum discharge, 52,300 ft3/s, 
  from rating curve extended above 12,000 ft3/s on basis of slope-area measurements at gage heights 18.98 ft and 
  25.30 ft.  Minimum gage height, 0.17 ft, Aug. 25, 1971.  Several measurements of water temperature were made 
  during the year.  Water-quality records for some prior periods have been collected at this location.

EXTREMES FOR CURRENT YEAR.--Peak discharges equal to or greater than base discharge of 3,500 ft3/s and maximum (*):

                   Discharge   Gage height                          Discharge    Gage height

Date      Time      (ft3/s)        (ft)           Date      Time      (ft3/s)       (ft)

Jan. 19    1115       *19,000       *15.73       June 10    1145       7,530         10.70

Jan. 27    1515       5,680         9.48         Aug. 13    0030       5,670         9.47

Feb.  9    1230       5,400         9.28         Sep.  4    1245       5,710         9.50

Mar. 20    0145       4,030         8.18         Sep.  6    2400       16,800        14.96

June  9    1630       9,210         11.64        Sep. 11    0830       5,960         9.68

  Minimum discharge, 37 ft3/s, Oct. 29, gage height, 1.05 ft, result of dam closure; minimum daily, 137 ft3/s,

  Nov. 27.

DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996

DAILY MEAN VALUES

DAY       OCT      NOV      DEC      JAN      FEB      MAR      APR      MAY      JUN      JUL      AUG      SEP

  1       145      159      388      228      868      463     1340      543      376      313      248      265

  2       145      178      367      304     e760      460     1120      491      352      474      240      254

  3       144      175      291      313     e630      449      932      441      324      397      212      400

  4       202      147      263      302     e520      412      840      411      494      319      240     1460

  5       815      158      243      290     e500      389      754      501      357      306      231      597

  6       575      154      205      266     e540      401      684     1040      320      299      259     9810

  7       280      270      260      237      591      442      650      833      412      270      254     5820

  8       235      250      224     e220      644      424      594      771      542      319      241     1740

  9       200      188      275     e220     4330      377      560      710     3830      548      636     1110

 10       182      199      242     e230     3320      378      509      617     4880      353      245      835

 11       175      334      195     e230     2370      363      472      643     3010      286      222     2190

 12       155      369     e190     e250     1910      349      448      568     1880      264     2160     1150

 13       158      312     e200      297     1350      340      450      496     1270      253     3460     1160

 14       190      272      217      310     1100      316      451      448      918      281     1100      863

 15       172      198      216      563      938      354      449      469      784      557      715      696

 16       181      225      267     1040      854      382      404     1090      638      475      536      852

 17       156      250      289      830      747      473      407     1520      590      342      449     1300

 18       159      201      338     1950      630      477      380     1040      512      297      404      954

 19       144      218      774    14200      584     1930      356      791      517      412      385      764

 20       202      205     1200     4330      638     3110      354      625     1040      326      329      640

 21       255      177      762     1910      620     1770      404      521      679      271      356      552

 22       239      183      556     1290      621     1230      377      465      514      255      356      561

 23       200      182      461      998      653      973      338      418      408      240      294      472

 24       179      186      380      902      648      829      341      387      472      229      327      432

 25       166      178      344      854      606      734      330      509      450      235      354      415

 26       161      176      327      709      576      648      318      430      410      249      423      401

 27       174      137      296     3930      557      554      315      483      350      248      330      404

 28       161      176      274     2560      541     1070      327      688      334      227      316      487

 29       139      727      216     1600      509     1810      317      556      321      233      313      652

 30       154      522      241     1200      ---     1720      527      484      324      233      296      462

 31       149      ---      224     1030      ---     1390      ---      408      ---      228      277      ---

TOTAL    6592     7106    10725    43593    29155    25017    15748    19397    27308     9739    16208    37698

MEAN      213      237      346     1406     1005      807      525      626      910      314      523     1257

MAX       815      727     1200    14200     4330     3110     1340     1520     4880      557     3460     9810

MIN       139      137      190      220      500      316      315      387      320      227      212      254

CFSM      .42      .46      .68     2.75     1.96     1.58     1.03     1.22     1.78      .61     1.02     2.45

IN.       .48      .52      .78     3.17     2.12     1.82     1.14     1.41     1.98      .71     1.18     2.74

  e Estimated.

ROANOKE RIVER BASIN

02056000  ROANOKE RIVER AT NIAGARA, VA--Continued

STATISTICS OF MONTHLY MEAN DATA FOR WATER YEARS 1927 - 1996, BY WATER YEAR (WY)

          OCT      NOV      DEC      JAN      FEB      MAR      APR      MAY      JUN      JUL      AUG      SEP

MEAN      357      370      471      636      760      910      831      567      421      295      346      322

MAX      1722     2100     2065     1941     1756     2846     3661     1447     1550     1396     2456     2051

(WY)     1938     1986     1949     1937     1994     1993     1987     1958     1972     1949     1940     1928

MIN      86.0      101      115      110      117      210      157      193      158      109     92.2     84.0

(WY)     1931     1942     1966     1966     1934     1981     1942     1930     1966     1930     1956     1954

SUMMARY STATISTICS           FOR 1995 CALENDAR YEAR        FOR 1996 WATER YEAR           WATER YEARS 1927 - 1996

ANNUAL TOTAL                      164754                     248286

ANNUAL MEAN                          451                        678                        523

HIGHEST ANNUAL MEAN                                                                        984              1949

LOWEST ANNUAL MEAN                                                                         198              1981

HIGHEST DAILY MEAN                 11300     Jan 15           14200     Jan 19           19700       Nov  4 1985

LOWEST DAILY MEAN                    128     Sep 14             137     Nov 27               8.0     Oct  9 1954

ANNUAL SEVEN-DAY MINIMUM             131     Sep  9             157     Oct 26              67       Jan 28 1966

INSTANTANEOUS PEAK FLOW                                       19000     Jan 19           52300       Nov  4 1985

INSTANTANEOUS PEAK STAGE                                         15.73  Jan 19             a25.30    Nov  4 1985

INSTANTANEOUS LOW FLOW                                          b37     Oct 29               1.0    cOct 16 1956

ANNUAL RUNOFF (CFSM)                    .88                       1.32                       1.02

ANNUAL RUNOFF (INCHES)                11.97                      18.04                      13.87

10 PERCENT EXCEEDS                   779                       1200                        985

50 PERCENT EXCEEDS                   271                        404                        312

90 PERCENT EXCEEDS                   156                        190                        136

  a From floodmark.

  b Result of dam closure.

  c Also Oct. 20, 1956, and Nov. 25, 26, 1990.