1914] Sumner, et al.: Physical Conditions in San Francisco Bay Di 
The first of the foregoing segments is that referred to as the 
““apper’” in the list of dredging stations (see Appendix I) ; the second 
and third together form the division referred to as the ‘‘middle’’ one; 
while the fourth is there referred to as the ‘‘lower’’ one. The second, 
third, and fourth segments form ‘‘San Francisco Bay’’ in the nar- 
rower sense in which the term is frequently used. 
? 
No streams of any considerable size discharge into San Francisco 
Bay, except near its upper end (San Pablo Bay), where the combined 
waters of the Sacramento and San Joaquin rivers enter through 
Carquinez Strait. Many of the numerous estuaries receive the drain- 
age of small creeks, which are, for the most part, dry or nearly so, 
throughout the long summer period. The extent of the discharge of 
fresh water into San Francisco Bay will be discussed at another point. 
IV. TIDAL RANGE AND CURRENT VELOCITY 
The vertical range of the tides at twenty-eight points within San 
Francisco Bay (ineluding San Pablo Bay) is given in the ‘‘Tide 
Tables’’ of the United States Coast and Geodetic Survey. The mean 
range for the mean tides, at all of these stations, is 4.49 feet (1.37 
meters). These stations are not, however, uniformly distributed 
throughout the bay, an undue proportion of them being located in 
the more central region, near the large cities. Nine of these stations 
have therefore been selected, at approximately equal distances from 
one another, as representative of the tidal range in the bay as a whole. 
The figures are presented herewith: 
TABLE 2 
RANGE OF TIDE, IN FEET, AT NINE PoINTS IN SAN FRANCISCO Bay 
(Figures from Tide Tables of U. S. Coast and Geodetic Survey, 1913) 
Locality Mean Spring Neap 
LONG ot) 2 ek ee 3.9 4.8 3.0 
TEX DAWA: Se YANSEEMG US 0) a eae eee ee eS 4.6 5.6 8) 
PROD ers Speen LN ee eee ceca eae nce ance osneeseseces 3.3 4.0 2.5 
Saree Mateo mE Oi tases reese eee Del 6.2 3.9 
Redwood City Creek, entrance .............. 6.1 7.4 4.7 
IWVeSt IB CLKel Ory, eetectecerge soeseotowehssesewsseeeseees 4.3 5.2 3.4 
Tetostiahy Skat, OPE y a ON aoe eee ae 4.1 4.9 3.2 
Petaluma PB Ouniti es sereescese eee eee ees - 4.5 5.4 3.5 
Mier emisNebrn QusTa ig tit s22e save nectesrecceseen een oaes 4.8 5.6 Bil 
OVE ari tee oats niet n= sas See ee Saree 4.52 5.46 3.49 
