Page:California Highways and Public Works Journal Vols 8-9.djvu/31

 HOW CALIFORNIA PREPARES FOR FLOODS (Continued from page 2.) not this amount will be found adequate and the division equitable through a period of years remains to be determined by experience.

Organization. The duties of the Department of Public Works in respect to flood control and reclamation are delegated to the Division of Water Resources, which succeeds the old Division of Engineering and Irrigation. The activities of this division in connection with the maintenance of the flood control project were commenced in September, 1927, and have been carried on continuously since that time.

The routine of maintenance consists of keeping in repair and condition the various works, levees and channels under the direct care of the division, and is carried on during the entire year by an organization engaged exclusively on this work, which includes bank protection.

During the flood season, this force patrols and inspects various levees and works, and is prepared to protect weak places as they appear and to make necessary repairs. Equipment, tools and supplies are kept available for immediate use in emergencies. Both the routine maintenance work and the special work which must be done each year during the flood involves Work of many varieties, and the crew is so organized that it may be expanded rapidly, with the various gangs in charge of foremen experienced in the particular kind of work required to be done.

During the year the size of the maintenance force varies from about thirty to seventy men, except during emergency when the number may be considerably greater. The larger items of work in connection with the routine maintenance, particularly replacements and improvements, are usually done by contract, but the nature of the greater portion of the activities is .such that it can best be performed directly by division forces. The bulk of the routine work is in connection with the Sutter-Butte By-pass Project No. 6 in Sutter County. This is in charge of a maintenance foreman with headquarters in Sutter City, which is also a central point for carrying on activities in the northern portion of the Sacramento Valley, extending from the vicinity of Marysville and Colusa north. All river bank protection work and work in the southern portion of the valley are done directly out of the Sacramento office of the division.

Routine Maintenance. The levees are kept free of noxious weeds and burrowing animals and the roads on the levees are kept in repair. These roads are used to a considerable extent by the public, but during wet weather the levees are closed by gates so that the surface will not be cut by traffic, When the maintenance force only is permitted to pass along the levees. Willows have been planted along the east levee of the Sutter By-pass for a distance of eleven miles, to produce a growth which will protect the levee from wave wash. The by-pass channel at this place has a width of 4000 feet, and the levee is exposed to a strong wave action during heavy south and southwest winds. These willows are planted in five rows five feet apart at the base of the levee, and it is necessary to irrigate them in the same manner that an orchard is irrigated. It is expected that an effective growth will be produced along a greater portion of this length within a period of three years. At the present time, all of the project levees are in good condition and there are no known weak points.

Pumping plants are maintained and operated to care for the intercepted drainage east of the Sutter By-pass. There are three of these plants, with a total of nine pumps and electric motors of 1500 total horsepower. Drainage water is conducted to these plants through 46 miles of canals of various sizes. These canals are kept clean and the canal structures, which are mostly bridges, are kept in repair.

In the by-passes there are numerous structures requiring maintenance, including bridges, weirs, bulkheads, jetties and current controlling structures. These are mostly of timber and require continuous repair. Some of them have been built for a number of years and replacements are necessary from time to time, which is done as maintenance.

A telephone system consisting of 30 miles of line and 12 telephones connects various parts of the project in Sutter County with the headquarters at Sutter City.

By-pass Clearing. One of the most serious and vexatious problems in connection with maintenance is that of keeping the by-passes and overflow flood channels clear of timber growth. No feasible and economical method has yet been devised to accomplish this, aside from cutting by hand labor. It is estimated that the area in the by-passes and the overflow channels on which there is a tendency for timber to grow exceeds