Watsonville Municipal Code Art. 4 Design Standards

(a) Slopes. Cut slopes shall be no steeper than three (3) horizontal to one vertical and shall not exceed twenty (20') feet in vertical height without a terrace break. Due to individual site soils and geology, flatter and shorter slope lengths may be conditioned on the permit by the City Engineer. Cut slopes shall be rounded off so as to blend in with the natural terrain.

(b) Stockpile materials. Stockpile materials for trenches and pits shall be put upslope of the excavation to be promptly backfilled and compacted into trenches and pits. Excavated materials not needed at the site shall be removed or disposed of at a location approved by the City Engineer.

(c) Vegetative protection. All earth cuts shall be planted or otherwise protected from storm runoff erosion within fifteen (15) days after the completion of the final erosion control and grading work. Planting shall be irrigated to establish a root system before October 15.

(§ 1, Ord. 538-81 C-M, eff. October 22, 1981)

(a) Fill locations. Fill placed on natural slopes shall be constructed as specified by the civil engineer or soils engineer, or by the City Engineer when less than 500 cubic yards, utilizing keys, drainage, and other measures necessary to assure a permanent and stable fill. The toe of the fill shall be no closer than twelve (12') feet horizontally to the top of the existing or planned cut slopes. The area beyond the toe of the fill shall be sloped for sheet overflow, or a drain shall be provided.

(b) Ground preparation. Natural ground surfaces over which fills are planned shall first be cleaned of all trash, vegetation, stumps, debris, noncomplying fill, topsoil, and other unsuitable materials and shall be scarified prior to the placement of the fill. Where slopes are five to one (5:1) or steeper, a keyway shall be dug, as determined by the soils engineer and/or engineering geologist, into undisturbed, solid competent soil or bedrock beneath the toe of the proposed fill. The keyway shall be at least ten (10') feet wide where fill is to be placed over a cut, and the terrace shall be cut and approved as a suitable foundation for fill before the fill is placed.

(c) Materials permitted. Only approved materials free of tree stumps, detrimental amounts of organic matter, trash, garbage, sod, peat, and/or similar materials shall be used. Rocks or broken concrete larger than six (6") inches in greatest dimension shall not be used. Topsoil may be used in the top twelve (12") inch surface layer to aid in planting and landscaping.

(d) Compaction of fills. All fills shall be compacted to a minimum relative dry density of ninety (90%) percent as determined by ASTM D-1557-78, or State of California test method number California 216, or Uniform Building Code Standard No. 70-1. Field density verification shall be submitted for any fill. A higher percentage density and/or additional compaction tests may be required at any time by the City Engineer.

(e) Fill slopes. Fill slopes shall be no steeper than three (3) to one and shall not exceed twenty (20') feet vertical height without a terrace break. Tops of fill slopes shall be rounded off so as to blend with the natural terrain.

(f) Vegetative protection. All earth fill shall be planted or otherwise protected from the effects of storm runoff within fifteen (15) days after the completion of the final grading, and planting shall be irrigated to establish a root system.

(§ 1, Ord. 538-81 C-M, eff. October 22, 1981)

(a) Minimum setbacks. Minimum setbacks for cut and fill slopes shall be set back from property boundaries and structures as far as necessary for the safety of the adjacent properties and to prevent damages resulting from water runoff by flooding, erosion of the slopes, or by sediment deposition. Setbacks shall be five (5') feet minimum from adjacent property.

(b) Stream and riparian setbacks. Toes of cut and/or fill slopes shall not encroach upon streams, floodplains, channels, or bodies of standing water and shall be set back far enough to provide and maintain an undisturbed protective strip between the grading and the riparian corridor. Such strip shall have sufficient filter capacity as determined by a biologist to prevent the degradation of the water quality. If it is determined that the filter capacity of the protective strip is insufficient, additional erosion and silt control may be required by increasing the width of the protective strip, and/or by the installation of structural measures, and/or by reseeding, planting, or mulching bare soil areas.

(c) Retaining walls. When keyed into stable foundation material and capable of sustaining the design loads, retaining walls may be used to reduce the required cut and fill setbacks when recommended by the civil engineer and/or engineering geologists and approved by the City Engineer. Retaining walls constructed in connection with site grading shall be constructed of concrete or masonry material. Retaining walls constructed on or within five (5') feet of property lines shall be constructed of concrete or masonry material. Masonry or concrete walls shall conform to the Public Improvement Standards or the Concrete Masonry Design Manual.

(§ 1, Ord. 538-81 C-M, eff. October 22, 1981, as amended by § 1, Ord. 636-84 C-M, eff. April 26, 1984)

(a) Drainage facilities.

(1) Disturbances of natural drainage ways shall be kept to a minimum, and existing drainage courses shall not be obstructed or obliterated without mitigating measures installed.

(2) Whenever a grading operation obstructs or impairs the flow of runoff in an existing drainage course, a culvert, bridge, or other suitable drainage facility properly designed and acceptable to the City Engineer shall be installed to convey the flow past the point of impairment. No construction materials or construction by-products shall be discarded in any drainage way or riparian zone.

(3) Drainage facilities shall be culverts, pipe drains, asphalt, or concrete channels designed to safely carry existing and potential off-site runoff from a fully-developed area upstream, as well as local on-site surface and subsurface waters to the nearest adequate drainage course designated for such purposes by the City Engineer. Properly designed energy dissipators shall be required at the point of discharge.

(4) Culvert size and industry standard materials shall be used in accordance with City standard design criteria and as approved by the City Engineer. The minimum pipe diameter shall be twelve (12") inches.

(5) Cuts, fills, and retaining walls shall have subsurface drainage facilities as necessary for stability.

(6) Berms, ditches, interceptor drains, or swales may be constructed at the top of cut and fill slopes when necessary for protection against water runoff. Interceptor drains above cut or fill slopes with an area exceeding one acre shall be paved with an approved non-erodible impervious material a minimum of three (3") inches thick, twelve (12") inches deep, and thirty-six (36") inches wide and shall discharge into downdrains. Asphalt ditches will not be allowed. Energy dissipators may be required by the City Engineer.

(7) At least a two (2%) percent grade will be required toward an improved storm drainage facility, either existing or planned, from all building sites, pads, yards, roof drains, and driveways.

(8) Grading equipment shall disturb or cross flowing streams only with prior approval from the City Engineer and the Department of Fish and Game of the State.

(b) Terraces.

(1) Terraces at least eight (8') feet in width shall be established at not more than twenty (20') foot vertical intervals. Suitable access shall be provided to permit the proper grading and maintenance of such terraces. Where only one terrace is required, it shall be at midheight.

(2) Swales or interceptor pipes, drains, or ditches on terraces and on the top of cut slopes shall be designed to carry water and sediment to safe disposal structures and areas. Swales shall be paved with an approved nonerodible material a minimum of three (3") inches thick, one foot deep, and five (5') feet wide when accepting drainage from an area of one acre or larger.

(§ l, Ord. 538-81 C-M, eff. October 22, 1981)

(a) General.

(1) Erodible areas. Buildings and access envelopes shall be delineated on the development plans when necessary to keep disturbances out of particularly erodible areas. Exposed soil shall be protected from erosion by temporary and/or permanent measures. Such protection may consist of mulching, plastic sheeting, vegetation, or other approved methods.

(2) Slopes. Structures on existing slopes exceeding thirty (30%) percent shall utilize pole, step, or other such foundations which do not require major land disturbances.

(3) Concentrated runoff. Where concentrated runoff will occur, it will be carried in pipe or culvert conduits or over asphalt or concrete surfaces. All conduits shall have proper energy dissipators at the point of discharge when necessary to prevent erosion.

(4) Building and site runoff. Runoff from buildings, roads, driveways, and the total site area shall be controlled by berms, swales, ditches, structures, vegetative filter strips, and/or catchbasins to prevent the escape of sediment from the site.

(5) Erosion control with project installations.

(i) All vegetative and/or structural measures required to discharge any accelerated runoff generated by the project shall be installed during the first or initial construction phase of the project.

(ii) Land shall be developed in increments of workable size which can be completed in a single construction season. Erosion and sediment control measures shall be coordinated with a sequence of grading, development, and construction operations, and erosion control measures shall be put into effect prior to the commencement of the next increment and/or winter rainy season.

(iii) Prior to the completion and final acceptance of the project, all erosion control measures shall be in place, and the soil shall be mulched, fertilized, and otherwise prepared so that the exposed bare soil is planted to a permanent vegetative cover. Native or naturalized vegetation should be used.

(6) Maintenance. All on-site erosion control facilities shall be properly maintained by the owners for the life of the project so that such facilities do not become nuisances with stagnant water, excessive algae growth, insect breeding, odors, discarded debris, and/or safety hazards. Vegetative maintenance measures required may include mowing, fertilization, irrigation, and replanting and/or reseeding.

(b) Summer operations: April 16 to October 14.

(1) Vegetative removal. Development plans shall indicate the areas where vegetation is to be removed and replaced within the building and access envelopes. Vegetation removal shall be limited to that amount necessary and as indicated on the approved development plan. The method and time shall be such that the erosive effects are minimized.

(2) Vegetative disposal. Vegetation removed during disposal operations shall be disposed of by chipping, used as mulch or compost, or be burned or hauled away. Burning shall comply with local air pollution district regulations, and no long branches or charred pieces shall be permitted to remain.

(3) Topsoil. To promote the regrowth of vegetation, the topsoil shall be stockpiled and reapplied upon the completion of the grading on slopes of less than five to one (5:1) twenty (20%) percent. Soil stockpiles and exposed soils shall be protected from wind and water erosion at all times.

(4) Temporary vegetation. Temporary vegetation of annual grass sufficient to stabilize the soil while permanent vegetation cover is maturing shall be used on all disturbed areas when needed and as each stage of grading is completed.

(5) Dust control. Dust from grading operations shall be controlled. The permittee shall be required to keep adequate equipment on the grading site to prevent dust problems.

(6) Seedbeds. A firm, rough seedbed free of rocks, stumps, and/or other debris shall be established. “New crop” certified seed, ninety-five (95%) percent pure, with a minimum of eighty (80%) percent germination, shall be used. Legume seed shall be inoculated with the proper strain of nitrogen-fixing bacteria. Fertilizer and seed may be applied by hydromulching or other methods.

(7) Planting: Maintenance. Within fifteen (15) working days after the completion of the final grading, all bare earth slopes shall be planted. Within fifteen (15) days after planting, the permittee shall commence the watering or irrigation of the planted area and continue until the ground cover is fully developed or the winter rains start.

(c) Winter operations. October 15 to April 15.

(1) Existing ground cover shall not be cleared, destroyed, burned, or disturbed more than fifteen (15) days prior to grading or construction work, unless approved in advance by the City Engineer.

(2) When land development work is allowed during the normal rainy winter season, adequate erosion and sediment control measures shall be in place during any land disturbance. Temporary erosion control measures of straw, plastic netting, and the like shall be applied to all soils bared at the end of each day and/or prior to a storm event. Sufficient erosion control materials shall be kept on the site at all times for installation.

(3) All cut and fill slopes without satisfactory vegetative cover between October 15 and April 15 shall be mulched with a minimum of 4,000 pounds per acre of slope surface or 1,000 pounds per 10,000 square feet. Mulch shall be anchored to the slope by punching or tacking into the soil or with netting installed over the mulch. Additional mulching and/or other anchoring methods may be required by the City Engineer.

(4) A firm, rough seedbed free of rocks, stumps, and/or other debris shall be established. “New crop” certified seed, ninety-five (95%) percent pure, with a minimum of eighty (80%) percent germination, shall be used. Legume seed shall be inoculated with the proper strain of nitrogen-fixing bacteria. Grass/legume seed and fertilizer mixtures shall be applied just prior to and along with the mulching required by subsection (3) of this subsection.

(5) Within ten (10) working days after seeding, fertilizing, and/or mulching, the permittee shall commence the irrigation of the seeded areas or slopes and shall continue until the ground cover is fully developed. Berms, diversions, catchbasins, or protective measures shall be installed prior to seeding and mulching.

(6) All erosion control planting and mulching shall be closely monitored throughout the winter and runoff problems corrected promptly. All erosion and/or slippage of banks shall be repaired by the permittee at the permittee’s expense.

(§ 1, Ord. 538-81 C-M, eff. October 22, 1981)

Paving on private property shall be any paving with asphaltic or concrete material on areas to be used for vehicle parking or storage, outdoor storage, access ways, loading docks, athletic courts, and other uses requiring asphaltic paving.

(a) Plans. Four (4) copies of a plan shall be submitted showing the location and extent of the work, the owner’s name and address, and the name and address of the persons preparing the plan. The plan should show the following:

(1) The location and dimensions of the area to be paved;

(2) The structural section of the paving;

(3) Sufficient grades to determine the direction of drainage;

(4) The drainage structures and piping; and

(5) A description of the conditions of the existing surface to be paved.

(b) Work time limits. The work time limits shall be as provided in Section 7-6.315 of Article 3 of this chapter.

(c) Fees. Fees shall be in accordance with Section 7-6.316 of Article 3 of this chapter. In addition, there shall be a drainage fee charged in accordance with the current City fee schedule.

(§ 1, Ord. 538-81 C-M, eff. October 22, 1981)