SAN FRANCISCO BAR.

The depth of water at the main channels across the bar has not materially changed since the first surveys of the bar were made in the year eighteen hundred and fifty-one, although, perhaps, at its south end some shoaling has taken place.

Should the flow of water across the bar be seriously diminished by a diminution in the tidal area of the bays which discharge and receive their water across the bar at each change of the tide, the depth of water upon the bar would in time diminish. Hence, any filling in of these bays between the limits of high and low tide is working to a greater or less degree an injury to the Harbor of San Francisco.

From lack of sufficient data, none of the witnesses before us were able to state when this injury would begin to be perceptible.

SACRAMENTO AND FEATHER RIVERS.

The bed of the Sacramento River, from its mouth to its junction. with the Feather River, has been filled since eighteen hundred and forty-nine to a considerable extent, so that during the low water of the past year the low water-mark at Sacramento City was about five feet above the low water-mark of eighteen hundred and forty-nine. The greater part of this filling of the river bed occurs during the dry season when the current is slight; during the freshet of the past winter the river has scoured in places down to its original depth.

The bed of Feather River, from its mouth to the head of navigagation, Marysville, has been filled to a depth of several feet. Navigation, however, during the low water of the past year, was uninterrupted, owing partly to the small size of the steamboats employed, and in a lesser degree to the flow of water from the mining reservoirs in the mountains.

This filling up of the beds of these streams has doubtless resulted in increasing the height of the floods, but to what extent only scientific inquiry can determine. The increase in the height of the flood-water, of course, makes the protection of the lands along these streams more difficult and costly.

OVERFLOW OF LANDS BY MINING DEBRIS.

A large amount of valuable bottom land near the mouths of the Yuba and Bear Rivers has been covered up with sand and soil, much the larger part of which has come from the gravel mines, rendering it, for the present at least, of no value for agricultural purposes. The injury to this land first began to be felt in the year eighteen hundred and fifty-eight, and assumed serious proportions during the flood of eighteen hundred and sixty-one and eighteen hundred and sixtytwo. Since that time this overflow has been steadily increasing. The testimony as to the amount of damage thus far caused to lands and improvements upon them varied greatly. Probably a total damage of two million dollars would not be very wide of the mark.

Should nothing be done to check this continued overflow, or if some plan be not speedily devised by which each stream can scour clean its channel, this damage will continue to increase, assuming more formidable difficulties in the way of its control than exist

at present. The owners of the lands thus injured have received no compensation of any sort for their losses.

HYDRAULIC AND GRAVEL MINING.

As gravel mining has resulted in covering up lands and improvements of such large value, and as a palpable method of averting further injury would be by preventing the working of these mines, your committee heard testimony as to their value and production. Their production for the year eighteen hundred and seventy-seven was stated to be about twelve million dollars, and their probable product for eighteen hundred and seventy-eight to be fourteen million dollars or fifteen million dollars. This production, witness stated, will probably increase within a few years to twenty million dollars per annum. Their present value was estimated at one hundred and fifty million dollars. This increased yield of gold, it was thought, would not result in an increased amount of gravel annually placed in the streams, owing to various causes, fully stated in the testimony. The stoppage of gravel mining would seriously and directly effect the welfare of one-sixth the population of the entire State.

PLANS FOR RELIEF FROM MINING DEBRIS.

One suggestion was, that the sediment from the mining rivers should be conducted by flumes to low lands adjoining the mouths of these streams, and there deposited. This, to a limited extent, has been done in Butte and Yuba Counties, resulting in some cases in improving the land on which it was placed.

Another suggestion, was by means of dams in the cañons of the rivers to hold back the heavier portions of the debris, while by confining the waters of the Sacramento and Feather Rivers the increased velocity of the water would result in scouring into the bays all the lighter particles passing over these dams.

CONCLUSIONS.

A large amount of damage has been done to valuable lands, the beds of two of the navigable rivers of the State have been partially filled, and this injury bids fair to increase. The industry from which a large part of this damage proceeds gives employment and sustenance to a considerable fraction of the population of the State. With all the statements that have thus far been placed before your committee, it is impossible for us to devise any present plan for relief. It was almost the unanimous opinion of the witnesses who appeared before us, that a thorough and complete examination of the facts and theories involved in these most dfficult problems should be made by impartial and scientific engineers, and who might, after making full examinations and surveys, be able to propose plans which will effectually remedy the present evils. In this view your committee coincides, and urges that an engineer or commission of engineers be provided for by the present Legislature, and who shall make a report giving the result of such surveys and examinations, to be presented before the ensuing Legislature, and which report we trust may serve as a safe guide for future legislative action.

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M. GARVER.