§ 13-11. Standards.

(a)

General: When a permit is required pursuant to this article, the grading plan and erosion and sediment control plan applicable to the project shall conform to the standards set forth herein.

(b)

Erosion and Sediment Control: A SWPPP detailing Best Management Practices shall be used for erosion and sediment control.

(1)

Sediment caused by the grading project shall be retained on the site to the greatest extent feasible. The rate of erosion after completion of the project should not exceed the natural erosion rate which occurred prior to the grading project. If erosion exceeds the natural rate, erosion and sediment control measures shall be immediately implemented to reduce erosion to allowable levels.

(2)

Where practical and feasible, sediment basins, sediment traps, or similar sediment control measures, temporary or permanent, shall be installed prior to grading operations. Upon completion of construction and stabilization of soils, all temporary erosion control facilities shall be removed from the site. All permanent sediment control measures must be maintained by the parcel owner. Notification of such maintenance must be provided annually by the owner to the Department of Public Works.

(c)

Established Vegetation:

(1)

Established vegetation shall be retained and protected, wherever possible, unless removal is required for public health and safety.

(2)

When vegetation must be removed, the method shall be one that will minimize the erosive effects from the removal.

(3)

Exposure of soil to erosion by removing vegetation shall be limited to the area required for immediate construction operations.

(d)

Grading Practices and Setbacks:

(1)

Grading operations shall be conducted so as to control sediment production and dust on the project site and other properties.

(2)

The setbacks specified by this section are minimum requirements and may be increased by the director or by the recommendation of a civil engineer, soils engineer or engineering geologist, if necessary for safety and stability, or to prevent damage to other properties, structures, channels, and roadways from deposition or erosion, or provide access for slope maintenance and drainage. Retaining walls and/or deep foundations may be used to reduce the required setbacks when approved by the director.

(3)

The required setbacks described in subsection (d)(2) above are as follows:

Slope Height (H) in Feet	Setback From Top of Cut or Toe of Fill, in Feet
H	Setbacks
0—10	5
10—30	H/2
Over 30	15

 

Increased setback may be required if interceptor drains are necessary.

(e)

Control of Runoff:

(1)

Each plan which makes changes in surface water drainage shall be required to:

a.

Make provision to handle upstream off-site runoff through the project site, based on projected storm runoff from the watershed.

b.

Provide and install, at the owner's expense, pertinent drainage, erosion and sediment control structures.

c.

Retain sediment being transported by runoff water on site through the use of sediment basins, silt traps, or similar control structures.

(2)

Release of concentrated surface water runoff shall only be directed into existing drainage facilities, swales or watercourses, at velocities which will not cause the natural erosion rate to be exceeded.

(f)

Slope Construction:

(1)

Slopes shall not be steeper than one-to-one (1:1) for cuts and one and one-half-to-one (1½:1) for fills, unless a steeper slope is determined suitable by geological and soils engineering analysis. Erosion control measures shall be included in the plans and specifications.

(2)

Slopes shall not be constructed so as to endanger or disturb adjoining property.

(g)

Revegetation and Slope Surface Stabilization:

(1)

Mulching, seeding, the planting of shrubs and trees, or other suitable stabilization measures shall be used to protect exposed slopes as necessary to control erosion, sedimentation and slope stability. Preference shall be given to using locally adapted grasses, shrubs and woody vegetation.

(2)

Earth or paved interceptors and diversions shall be installed at the top of cut or fill slopes where there is a potential for erosive surface runoff.

(3)

Revegetation shall be maintained by the owner until permanent establishment is achieved.

(h)

Grading:

(1)

All land within a development site shall be graded to drain and dispose of surface water without ponding, except as otherwise provided herein.

(2)

Where drainage swales are used to divert surface waters, they shall be vegetated or protected, as required.

(i)

Protection of Watercourse:

(1)

Fills shall not block or change natural watercourses or constructed channels.

(2)

Excavated materials shall not be deposited or stockpiled in or alongside the streams, lakes or watercourses where the materials may be washed away by high water or storm runoff.

(j)

Disposal of Cleared Vegetation: Vegetation removed during clearing operations shall be disposed of by one (1) or more of the following methods:

(1)

Chipping all or some of the cleared vegetation for use as mulch or compost on the site.

(2)

Burning all or some of the cleared vegetation. Material to be burned shall be piled in a manner and in such locations as will cause the least fire risk and least damage to adjacent trees. Burning shall be thorough, so that the materials are reduced to ashes. No logs, branches or large charred pieces shall be permitted to remain. Burning shall comply with Butte County Air Pollution Control District and local fire department or district regulations.

(3)

Disposing of the balance of the material in a manner and at a location approved by the director.

(k)

Excavated and Fill Materials: Excavated material removed during grading operations and imported fill material shall be handled in accordance with the following methods:

(1)

Stockpiling sufficient topsoil on the site if necessary for use on areas to be revegetated.

(2)

Locating stockpiled soil so that it will not become a source for off-site sediment damage.

(3)

Promptly backfilling and compacting stockpiled soil into trenches and pits to reduce the risk of erosion.

(4)

Applying mulch or other protective coverings on stockpiled material which will be exposed through the winter season.

(5)

Excavated material not to be used at the site shall be disposed of in a manner and at a location approved by the director.

(6)

At the discretion of the director, excavated material and imported material placed in permanent fill may be required to be compacted in accordance with section 19 of the State of California Department of Transportation Standard Specifications dated July 2001.

(Ord. No. 2680, § 2, 4-26-88; Ord. No. 2738, § 1, 3-7-89; Ord. No. 4011, § 1, 12-8-09)