11181000 SAN LORENZO CREEK AT HAYWARD, CA

LOCATION.-Lat 37°41'08", long 122°03'48", in San Lorenzo Grant, Alameda County, Hydrologic Unit 18050004, on left bank, 300 ft downstream of Center 
Street Bridge, just outside city limits of Hayward, 0.6 mi downstream from Crow Creek, and 1.0 mi downstream from Don Castro Dam. 
DRAINAGE AREA.-37.5 mi2. 
PERIOD OF RECORD.-October 1939 to September 1940, October 1946 to Apr. 28, 1983; October 1997 to September 1998.  Monthly discharge only for some periods, 
published in WSP 1315-B. 
  REVISED RECORDS.-WSP 1315-B:  1947(M), 1949(M).  WSP 1345:  1940(M).  WSP 1715:  1947.
GAGE.-Water-stage recorder and crest-stage gage. Datum of gage is 133.16 ft above sea level.  January to September 1940, nonrecording gage on bridge 0.1 mi 
upstream at present datum. 
REMARKS.-Records fair.  Flow partly regulated since October 1962 by Cull Creek Reservoir, capacity, 310 acre-ft, and since January 1965 by Don Castro Reservoir, 
1.0 mi upstream, capacity, 380 acre-ft.  A few very small diversions above station for irrigation. 
EXTREMES FOR PERIOD OF RECORD.-Maximum discharge, 8,140 ft3/s, Feb. 3, 1998, maximum gage height, 21.85 ft, Feb. 3, 1998; no flow at times. 
EXTREMES FOR CURRENT YEAR.-Peak discharges greater than base discharge of 550 ft3/s, or maximum: 
  			Discharge	Gage height			Discharge	Gage height
  	Date	Time	(ft3/s)	(ft)	Date	Time	(ft3/s)	(ft)
  	Jan. 12	1500	2,010	11.34	Feb. 7	1615	1,360	10.21
  	Jan. 15	1415	1,710	10.55	Feb. 14	1400	980	9.03
  	Jan. 18	1600	2,910	13.42	Feb. 21	1330	1,560	10.77
  	Jan. 29	0515	647	7.00	Mar. 13	0830	598	7.61
  	Feb. 3	0200	8,140	21.85

        DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1997 TO SEPTEMBER 1998                   

                       DAILY MEAN VALUES                                                
 
DAY       OCT      NOV      DEC      JAN      FEB      MAR      APR      MAY      JUN      JUL      AUG      SEP
 
  1      e.38     e1.3    e16        4.2      119       86       49       17     12        8.1     e3.7    e1.6 
  2      e.79     e1.5    e11       26        784       79       45       17     10        8.0     e3.4    e1.6 
  3      e.53     e1.5     e7.1     15       2000       75       95       20     11        8.5     e3.1    e1.6 
  4      e.52     e1.4     e5.8    123        369       66      117       16     10        7.5     e2.9    e1.5 
  5      e.51     e1.3     e6.8     21        260       76       62       28      9.7      6.4     e2.6    e1.5 
 
  6      e.50     e1.3     e6.0     14        587       73       58       17      9.5      6.9     e2.7    e1.4 
  7      e.52     e1.5   e100       14        559       65       55       16     11        5.6     e2.8    e1.4 
  8      e.73     e2.0    e47       11        428       60       48       15     10        6.1     e2.9    e1.3 
  9     e3.2      e2.2    e17       13        252       52       44       12      9.7      5.6     e2.9    e1.3 
 10     e1.4     e21        8.7     54        202       47       41       11      9.5      6.7     e2.8    e1.5 
 
 11      e.79     e5.1      6.6    169        166       44       40       12      8.5      6.6     e2.5    e1.3 
 12      e.65     e2.0      5.6    722        173       45       37       21      7.8      5.7     e2.4    e1.2 
 13      e.64     e2.2      4.9    161        138      191      133       16      7.0      4.5     e2.1    e1.1 
 14      e.59     e3.2     33      119        382       67       72       15      6.6      4.4     e2.1    e1.1 
 15      e.59    e19       11      606        202       57       54       18      7.1      4.1     e2.5    e1.2 
 
 16      e.58     e5.4      7.0    255        196       55       51       18      7.3      5.0     e2.5    e1.3 
 17      e.60     e1.8      6.4    156        166       51       46       19      5.7      4.7     e2.4    e1.1 
 18      e.62     e1.9      5.9    685        133       47       45       18      5.0      4.2     e2.7      .85
 19      e.67     e5.1      5.1    295        280       44       42       15      4.9      3.8     e2.7     1.1 
 20      e.70     e1.8      4.8    164        163       43       37       13      4.3      3.7     e2.6     1.1 
 
 21      e.66     e1.2      4.9    118        425       41       40       15      3.7      3.8     e2.5      .93
 22       .65     e1.2      4.3     90        231       38       39       14      3.5      4.3     e2.2      .56
 23       .71     e1.5      4.0     72        285      110       30       15      5.4      4.4     e2.2      .52
 24       .65     e4.6      4.0     62        177      133       29       13      5.3     e4.1     e2.1      .73
 25       .65     e3.9      4.1     51        147       98       24       12      7.4     e3.7     e2.1      .83
 
 26       .69    e80        3.9     48        124       65       22       14      7.3     e3.5     e2.3     1.1 
 27       .61    e19        4.2     57        108       62       19       23      6.8     e3.1     e2.1     1.5 
 28       .65    e11        4.5     43         96       57       20       69      7.3     e3.3     e1.9     2.6 
 29       .66     e8.9      4.5    262        ---       48       23       22      7.5     e3.6     e2.0     2.4 
 30      e.88    e28        4.4     91        ---       44       19       15      7.5     e3.8     e1.9     2.9 
 31     e1.3       ---      4.3     86        ---       71      ---       12      ---     e3.8     e1.8      ---
 
TOTAL   23.62    241.8    362.8   4607.2     9152     2090     1436      558    228.3    157.5     77.4    40.12
MEAN      .76     8.06     11.7      149      327     67.4     47.9     18.0     7.61     5.08     2.50     1.34
MAX       3.2       80      100      722     2000      191      133       69       12      8.5      3.7      2.9
MIN       .38      1.2      3.9      4.2       96       38       19       11      3.5      3.1      1.8      .52
AC-FT      47      480      720     9140    18150     4150     2850     1110      453      312      154       80
 
    e  Estimated.


STATISTICS OF MONTHLY MEAN DATA FOR WATER YEARS 1940 - 1998, BY WATER YEAR (WY)                                 
          OCT      NOV      DEC      JAN      FEB      MAR      APR      MAY      JUN      JUL      AUG      SEP
MEAN     3.78     3.58     21.7     56.4     53.2     37.9     25.3     5.57     2.24     1.00      .69      .59
MAX       107     30.1      184      227      327      267      255     21.3     9.03     5.22     4.58     2.89
(WY)     1963     1951     1956     1952     1998     1983     1958     1967     1967     1982     1980     1968
MIN      .000     .000      .13      .39      .73      .84      .29      .12     .043     .000     .000     .000
(WY)     1947     1949     1949     1949     1948     1972     1977     1976     1977     1961     1947     1947
 
SUMMARY STATISTICS                            FOR 1998 WATER YEAR                        WATER YEARS 1940 - 1998
 
ANNUAL TOTAL                                    18974.74                                                        
ANNUAL MEAN                                        52.0                                     16.4                
HIGHEST ANNUAL MEAN                                                                         56.4            1982
LOWEST ANNUAL MEAN                                                                            .63           1977
  HIGHEST DAILY MEAN                               2000      Feb  3                         2600       Oct 13 1962
  LOWEST DAILY MEAN                                    .38   Oct  1                             .00    Sep 19 1940
  ANNUAL SEVEN-DAY MINIMUM                             .54   Oct  1                             .00    Oct  1 1946
  INSTANTANEOUS PEAK FLOW                          8140      Feb  3                         8140       Feb  3 1998
  INSTANTANEOUS PEAK STAGE                           21.85   Feb  3                           21.85    Feb  3 1998
ANNUAL RUNOFF (AC-FT)                           37640                                    11880                  
10 PERCENT EXCEEDS                                133                                       34                  
50 PERCENT EXCEEDS                                  7.5                                      1.5                
90 PERCENT EXCEEDS                                  1.1                                       .00