The great floods of 1861-62 wore the most overwhelming and disastrous that have visited this state since its occupation by Americans. The first flood submerged the Sacramento Valley about the 10th of Docember. the water rising higher than in either of the memorable floods of 1849 and 1852. For six weeks thereafter an unusual amount of rain descended ; and during that time the deluge but partially subsided, the streams still carried torrents, and the lowlands were overflowed. On the 24th of January the second flood attained its greatest height, and the Sacramento and San Joaquin valleys were transformed into a broad inland sea, stretching from the foothills of the Sierras to the Coast Range, and somewhat similar in extent and shape to Lake Michigan.

The raging mountain torrents swept away bridges, fences, houses, mills, and the most durable improvements in their reach; not infrequently ploughing new channels through the country, and depositing the debris of sand and rock upon large sections of cultivated land.

But the flood was not attended with unmixed evil. The streams that had been choked by tailings for years were suddenly cleared of their obstructions, and extensive river beds were again opened to the enterprise of the miner. The work of rebuilding bridges and mills, and of repairing other damages, called into profitable employment a large number of persons; and trade and commerce and actual improvement suffered less interruption than might naturally have been expected, after so great a blow to our prosperity; and such are the wonderful energies and resources of our people, that in a few months the ravages of the flood had disappeared, and losses estimated at millions had been retrieved.

* * * Dr. Logan remarks that, on the occasion of the first inundation at Sacramento on December 7, 1861, "It commenced raining at 12 m., and ended at 9 a.m on the 9th; amount in inches, 2.570; the flood commenced at 10 a.m. of the 9th of December and at 10 p.m. had reached 2 feet 6 inches in my office; by daylight it had all subsided. At the second inundation, on January 5, 1862, rain commenced at 10 a.m. and ended at 1.30 a.m. on the 6th; during that interval there fell 2.690 inches. On January 8th, rain commenced at 11 a.m. and ended at 7 a.m on the 10th ; between which periods there fell 2.840 inches. On .January 10th the flood reached my floor at 2 p.m. and at 8 p.m. came to a stand of 3 feet 11 inches above my floor. The Sacramento River rose during this night to 24 feet above low water mark. On the 14th, the water had receded from my floor. * * * "

Assuming the entire watershed drained through the Straits of Carquinez as occupying an area equal to 50,000 square miles, and that the rainfall averaged over the entire area a depth equal to four inches in twenty-four hours--and for some days in January last it certainly must have exceeded that amount--it would be equal to 5,377,785 cubic feet per second, or four times the highest gage ever made of the Mississippi at its highest floods. The whole of this immense volume has no outlet excepting a passage not greater than 300,000 feet sectional area, with the further disadvantage that this outlet is subjected to tidal influence. Under such circumstances, that the low-lying country to the east of Carquinez should become inundated, and that for a long period, is not surprising. The inundation thus caused, extended over probably more than 6,000,000 acres. * * * Most singular of all, however, was the fact that the bay fishermen frequently caught fresh water fish in the bay; for from two to three months, the surface portion of the entire waters of the bay of San Francisco consisted of fresh water, to the depth of from eighteen to twenty-four inches. * * * At the Colden Gate, for nearly a fortnight, the stream on the surface was continuously flowing toward the Pacific, composed

entirely of fresh water, the tide not affecting the surface flow, and the water was brackish at the Farallone Islands.

In the early days of gold mining in the Sierra Nevada only a moderate amount of earth was disturbed. An army of men were engaged, but they worked as laborers, with pick, shovel and rocker. It was only gradually that more efficient methods were developed; but finally the resources of the engineer were brought to bear, water power was substituted for man power, and vast quantities of earth were handled. At the height of the hydraulic mining, when hundreds of large jets of water were turned on the auriferous deposits, the material annually overturned was reckoned in scores of millions of cubic yards.

The material thus washed from the hillsides consisted chiefly of sand and the finer detritus called "slickens," but included also much gravel and many cobbles and boulders. The slickens was taken in suspension by the water used in mining and went with it to the creeks and rivers. Much of it escaped from the mountains altogether and found eventual lodgment in the Great Valley of California or in the tidal waters of San Francisco Bay and its dependencies. The coarse stuff tarried by the way, building up alluvial deposits on the lower hill slopes, in the flatter creek valleys, and in the river canyons. When rains and floods came the sands and gravels were moved forward toward the lowlands, and in 1862 a great flood washed so large a quantity into the lower reaches of the Sierra rivers and into the rivers of the Great Valley that the holders of riparian lands became alarmed. The mining-debris question, then for the first time generally recognized, assumed greater and greater importance and prominence in subsequent years and led to protest and litigation which in 1884 culminated in a series of injunctions whereby the miners were restrained from casting their tailings into the streams. The petitioners were valley dwellers, and the evils cited by them included the burial of alluvial farming lands by the flood of debris, the obstruction to navigation from shoaling of Sacramento and Feather rivers, and the raising of the flood levels of the valley streams whereby the area of periodic inundation was increased and protection against inundation became more difficult and expensive,

There are those still living who may remember the course which the waters of the American River took across the eastern portion of Sacramento in the great flood of 1862. The small levee that had been provided to keep out the American River proved inadequate. It was easily breached by the river and the water followed a natural depression southwesterly into the City of Sacramento and thence southerly toward Sutterville and into the Sacramento Flood Basin.