39 



/Formal River Ofscf/ARot 

 S^c/iA»ft/vro HiviR 

 3ACRA/ireAfTO ajvd San JoActutN RivtAS Co/»ta//t£o 



Fig. 18. Normal river discharge, Sacramento River and Sacramento and San Joaciuin Rivers 

 combined. 



"May 19, 1817. (Contiiuiini; up tlu- rher near the site of Sacramento.) 

 The river is much swollen and is Hooded on both sides, so that one can 

 scarcely alight upon land." 



"May 24, 1817. At niitlday we set out to join the commandant at the 

 strait of Chupcanes (Carquinez), which we reached at six o'clock in the 

 afternoon, finding the said gentleman there; he had arrived in the morning. 

 We traveled this afternoon as far as the mouth of the San Joaquin. It is 

 necessary to pass this at high tide, because there is a sand bar, and the 

 launches are blocked by it. There is this difference between the Sacramento 

 and the San Joaquin; the latter carries less volume of water, although in 

 some places it is wider; and in all that part which we have traveled there is 

 nothing but tule, without a tree under which the navigator may find shade, 

 nor a stick of firewood with which to warm himself; whereas the Sacramento, 

 when it is not flooded, has dry land on both banks covered with poplar 

 groves, as has been said, and it seems to carry a greater abundance of 

 water." 

 Commander Cadwalader Ringgold, U. S. Navy, reported his observations and 



surveys of 1849 and 1850. On page 39 of his report, the following important fact is 



stated: 



"At the lowest stages of the water, the maximum depth availal)le for 

 vessels proceeding up the Sacramento River, owing to the obstructions 

 existing in portions of the channels, does not exceed ten feet; from six to 

 eight in the San Joaquin Ri\-er." 



MODIFICATIONS OF RIVER REGIMEN BY HUMAN ACTIVITY 



The regimen of the two large rivers which discharge into the upper bays has been 

 materially modified by human activities. Hydraulic mining contributed enormous 

 amounts of sand and sediment to the natural sediment load of the two rivers — more 

 particularly to that of the Sacramento River. It is not proposed to discuss this prob- 

 lem fully. It will suffice to call attention to the fact that under original conditions. 



