California Code of Regulations › Title 14 - Natural Resources › Division 9 - Delta Protection Commission › Chapter 3 - Regulations Governing Land Use and Resource Management in the Primary Zone of the Sacramento-San Joaquin Delta › Section 20100 - Levees

Current through Register 2024 Notice Reg. No. 28, July 12, 2024
(a) Overview
The Delta is the natural drain for a watershed that includes
				  the Central Valley and the western slope of the Sierra Nevada from Fresno to
				  Mount Shasta. Existing flood management and water supply facilities (dams,
				  levees, and bypasses) throughout the watershed influence floodflows to the
				  Delta. Settlers began to farm the rich lands of the Delta by the 1850s. They
				  built low levees to allow land to be drained for farming. Few of these levees
				  were built using modern engineering techniques, and many rest on peat
				  foundations that have settled with the added weight.
The main flood management facilities in the Delta include the
				  approximately 1,100 miles of levees and the Yolo Bypass. The Yolo Bypass, with
				  about 500,000 cubic feet per second (cfs) capacity, was designed to flood
				  occasionally to relieve high water stages on the Sacramento River. Easements
				  held by the Central Valley Flood Protection Board provide the right to inundate
				  the land, including some islands such as Liberty Island, with floodwaters. The
				  lower Sacramento ship channel and the Stockton ship channel provide some
				  flood-carrying capability. Dredging to enlarge and clean Delta channels used to
				  be an important element of flood management.
Levees can fail for various reasons including the burrowing
				  activities of animals, erosion, overtopping, deferred maintenance, seepage
				  through sand layers underlying levee foundations, slope stability and other
				  causes.
Delta levees face risk of high water overtopping during the
				  wet season (winter and spring), particularly when large storms coincide with
				  high tides. Storms contribute to the levee overtopping risk by increasing water
				  levels in the rivers and creating wind-induced waves. In addition, the low
				  barometric pressures associated with large storms raise water surface levels in
				  Delta and Suisun Marsh channels. In many cases, the flooding of the islands has
				  been costly to local residents and farmers and to the state as a whole. Damage
				  to levees could also occur due to sea level rise and other aspects of climate
				  change.
(b) Goal
Support the improvement, emergency repair, and long-term
				  maintenance of Delta levees and channels. Promote levee maintenance and
				  rehabilitation to preserve the land areas and channel configurations in the
				  Delta as consistent with the objectives of the Act.
(c) Policies
(1) Local governments shall carefully and
				prudently carry out their responsibilities to regulate new construction within
				flood hazard areas to protect public health, safety, and welfare. These
				responsibilities shall be carried out consistent with applicable regulations
				concerning the Delta, as well as the statutory language contained in the Delta
				Protection Act of 1992. Increased flood protection shall not result in
				residential designations or densities beyond those allowed under zoning and
				general plan designations in place on January 1, 1992, for lands in the Primary
				Zone.
(2) Support programs for
				emergency levee repairs and encourage coordination between local, State, and
				federal governments. The programs may include but are not limited to:
				interagency agreements and coordination; definition of an emergency;
				designation of emergency funds; emergency contracting procedures; emergency
				permitting procedures; and other necessary elements.
(3) Support efforts to address levee
				encroachments that are detrimental to levee maintenance.
(4) Support funding assistance for existing
				unincorporated towns within the Delta to improve levees up to a 200-year flood
				protection level.
(5) Support
				stockpiling rock in the Delta for levee emergency response.
(6) Support a multi-year funding commitment
				to maintain and restore both project and non-project levees in the
				Delta.
(7) Encourage the beneficial
				reuse of dredged material, as appropriate, for levee maintenance and
				rehabilitation, and the maintenance of instream flows. Support and advocate for
				the Delta Long-Term Management Strategy (LTMS).
(8) Seek funding for and support programs to
				make cost-effective levee investments in order to preserve the economy and
				character of the Delta.
(9) Support
				a minimum Delta-specific levee design standard as established by state and
				federal regulations.