RR 6. IMPROVEMENT OF SAN JOAQUIN RIVER, CAL. At the beginning of the fiscal year it was found that to obtain a channel in Stockton Channel 200 feet wide and 9 feet deep at low water, as required by the project adopted by Congress on June 25, 1910, would require the removal of about 170,000 cubic yards. It was also found from a survey that it would require the removal of about 90,000 cubic yards additional to extend this channel 75 feet wide and 4 feet deep at low water up Mormon Slough to Miller's warehouse, a distance of 4,500 feet. This work was done under contract and completed in January, 1911, and the full channel dimensions required by approved project were thereby obtained. There was a total of 275,285 cubic yards dredged at a contract price of 6.89 cents per cubic yard. The floods in the early part of 1911 brought down large quantities of detritus that was not carried off by the diverting canal to the east. From a survey made recently it was found that the deterioration in Mormon Slough amounts to about 34,000 cubic yards. It is estimated it would cost about 7 cents per yard to redredge this channel with a clamshell dredge. So far Stockton Channel has escaped deterioration from this source, but it is probable that another rainy season will carry the material on into the channel where it will have to be removed by hydraulic dredge at about 12 to 15 cents per cubic yard. Estimate of additional funds required. Amount that can be profitably expended in fiscal year ending June 30, 1913, for works of improvement and for maintenance.. 1 $100,000 Contract dated September 23, 1910, for dredging about 257,000 cubic yards of material from Stockton Channel and Mormon Slough, Cal.: Rate: 6.89 cents per cubic yard. Name of contractor: Antioch Dredging Co. Date of commencement: October 3, 1910. Date of completion: January 7, 1911. Date of approval: Emergency contract, not approved by Chief of Engineers. 1 Exclusive of the balance unexpended July 1, 1911. COMMERCIAL STATISTICS. Season of navigation.-Opened, January 1; closed, December 31. IMPROVING STOCKTON AND MORMON CHANNELS, CAL. At the beginning of the year work was in progress under contract with the Standard American Dredging Co. on the canal section of the Diverting Canal being constructed to divert the waters of Mormon Slough across the country east of Stockton and into the Calaveras River. Work was completed on September 3, 1910, a total of 87,437 cubic yards having been excavated during the year at a cost of 15 cents per cubic yard. A total of 1,465,563 cubic yards of material was excavated in constructing this Diverting Canal, one railroad and six highway bridges were built, and one railroad bridge was extended. In September, 1910, the Diverting Canal was cleaned of weeds, willows, and brush by hired labor at a total cost of $378.85. This canal was given a severe test during the early part of this year when a succession of floods caused unusually high water several times, but the levee on the lower side of the canal proved ample to withstand all water turned into the canal. Considerable driftwood was lodged against the bridges over the canal, some pile supports were knocked out, approaches to the bridge were washed out, and the retaining levee broken at one place. All damage done to bridges and approaches except in the case of the Sanguinetti Bridge was repaired by hired labor at a total cost of $2,966.54, including some incidental expenses. The country to the east and north of the canal was flooded for several miles and damage was done to early crops, fences, and buildings. As far as is known, the damage done to the land was not permanent and the land has been put into crops this year. Considerable additional expense for pumping was rendered necessary in some cases. It is not thought that the damage can be attributed solely to the diverting canal. The floods in this section were greater than usual and the levees on the Calaveras River above the canal had been allowed to deteriorate so as to be of little value. With the funds available it is not practicable to make the canal of sufficient size to carry all the flood water, but the channel will be cleared at the more congested parts. This canal, however, does not entirely fulfill the purpose of the project to keep material out of Stockton Channel. The south bank of Mormon Slough above the head of the canal is overflowed at high water and considerable quantities of detritus are carried down into the improved channel in Mormon Slough and will doubtless extend into Stockton Channel in the course of time. This had been foreseen and the city of Stockton and private owners informed. The Diverting canal and levees protected the city of Stockton from being flooded two or three times during the rainy season. The high water scoured out the channel in the full length of the Canal, and it is now in better condition that it was when first completed. Aside from the above flood damage very little deterioration to Government works at this locality has taken place, as all the works have been but recently constructed. It is proposed to expend the balance on hand in increasing the water-carrying capacity of the channel. This improvement is considered worthy of maintenance to divert the waters of Mormon Slough away from Stockton Channel and save some of the expensive annual dredging found necessary in past years. Estimate of additional funds required. Amount that can be profitably expended in fiscal year ending June 30, 1913, for maintenance of improvement.. 1 $25,000 CONTRACT IN FORCE. Contract dated August 15, 1908, for excavating 834,100 cubic yards of material and building embankments and dam at 15.5 cents per cubic yard, and building bridges at $1,623, $1,753, $1,493, $1,429, and $5,500 each. Name of contractor: Standard American Dredging Co. Date of commencement: November 3, 1908. Date of completion: September 3, 1910. Date of approval: August 24, 1908. Date of expiration: March 18, 1910, under supplemental contract. R R 8. IMPROVEMENT OF MOKELUMNE RIVER, CAL. Toward the end of the preceding year a clamshell dredge was leased from N. R. Harris at a rate of $125 per day of 22 hours. This dredge was employed in cutting the channel through sand bars and removing overhanging limbs and trees. Work was completed on July 20, 1910, having removed a total of about 30,000 cubic yards of material at a total cost of $1,801.14. In addition to work by the United States, the State of California and private parties did considerable work above the Galt-New Hope Bridge, the upper limit of the present project. This made a navigable channel 2 or 4 miles in length and the amount of money expended thereon is reported as being $22,782.39. From observation it is found that this part of the river is as yet used little for commerce, but the improvement is valuable in facilitating flood control. It is impossible to state the amount of deterioration of the channel of this river without a survey. Repairs are usually best effected by leasing a dredge for about $125 per day of 22 hours. Estimate of additional funds required. Amount that can be profitably expended in fiscal year ending June 30, 1913, for maintenance of improvement... 1 $1,000 CONTRACT IN FORCE. Contract dated June 9, 1910, for lease of clamshell dredge Golden Gate, for dredging in Mokelumne River, Cal. Name of contractor: N. R. Harris. Rate: $125 per day of 22 hours. Date of commencement: June 16, 1910. Date of completion: July 20, 1910. Date of approval: Emergency contract not approved by Chief of Engineers. COMMERCIAL STATISTICS. Vessel classification. It has been impossible to obtain any detailed information in regard to the vessel classification for this stream. IMPROVEMENT OF PETALUMA CREEK AND NAPA RIVER, CAL. (A) PETALUMA CREEK. Contract was entered into during the year with N. R. Harris to dredge the upper part of Petaluma Creek at a contract price of 11.74 cents per cubic yard. A total of 80,862 cubic yards was removed and the full width and depth of channel required by approved project was obtained. Aside from the channel in the creek proper, there has been a gradual shoaling in San Pablo Bay at the approach to the mouth of the creek. This shoaling has been accumulating for many years, and now it seriously hampers navigation in and out of the creek. No work has ever been done at this point, so that this can not be considered strictly a deterioration of any work of improvement. This locality is considered worthy of further improvement to the extent of maintaining the present authorized channel in the creek proper, and also providing a channel of corresponding width and depth across the flats in San Pablo Bay at the approach to the mouth of the creek. The amount of deterioration of the channel of this creek is estimated at 34,000 cubic yards, and the cost of removing this material is estimated at 16 cents per cubic yard. |