Atherton Municipal Code Ch. 16.32 Improvements

Sections:

• 16.32.010 Standards. 16.32.020 Required improvements. 16.32.030 Approval—Acceptance. 16.32.040 General requirements. 16.32.050 Drainage requirements. 16.32.060 Survey and monuments.

All improvements hereinafter mentioned shall conform to the specifications prescribed by the city engineer. All improvements shall include facilities for the handicapped if required by federal, state or local law. Fire protection facilities shall be installed and operable prior to placement of any combustible materials on the site. (Ord. 441 § 1, 1988)

A. Improvements Required of All Subdivisions. The improvements set forth in this chapter shall be required of all subdivisions. The subdivider shall pay the expense of all required improvements.

B. Approval by City Engineer. Improvement work shall not be commenced until improvement plans and profiles for such work have been submitted to and approved by the city engineer. All such plans and profiles shall be prepared in accordance with requirements of the city engineer. Final plans shall be filed with the city engineer and city clerk.

C. Notification. Improvement work shall not be commenced until the city engineer has authorized the work to proceed. If work has been discontinued for any reason, it shall not be recommenced until the city engineer has so authorized.

D. Construction of Improvements. The inspection and control of work and the access to said work shall be as follows:

1. All work done in constructing the improvements and all materials furnished shall be subject to inspection and testing by the city engineer;

2. The city engineer shall have access to the work at all times during its construction and shall be furnished with every reasonable facility for ascertaining that the materials used and the workmanship are in accordance with the requirements of this title.

E. Work Done Without Approved Plans. If any work or improvement is done by the subdivider prior to the approval of the improvement plans, or prior to the inspections or tests required by the city engineer, such work may be rejected and shall be deemed to have been done at the risk and peril of the subdivider. If any portion of the work has been done at the time of filing the improvement plans, the subdivider shall pay to the town all necessary costs for the inspection and testing required to verify the quantity and quality of the work done.

F. Prosecution of the Work. The subdivider shall prosecute the work to completion without undue delay. Delay in completion of the work beyond the period stated in the subdivision agreement, unless an extension thereof is approved by the city council and the surety company, may result in forfeiture of the security, or a portion thereof, for the completion of the work. (Ord. 441 § 1, 1988)

A. City Engineer’s Certificate of Completion. When all improvement work required by the improvement plans, or a complete unit thereof, is complete to the satisfaction of the city engineer, he shall inform the city council that the work, or a portion thereof, has been satisfactorily completed and recommend the acceptance by the city council of the completed portion.

B. As-Built Drawings. Plans showing all subdivision as-built improvements shall be filed with the city engineer upon completion of the improvements, together with a final written report by the subdivider’s engineer on all said improvements.

C. Refund of Cash Deposit. Any unexpended cash deposits not required for completion of the work shall be refunded upon acceptance of the improvements by the city council subject to posting of a satisfactory maintenance guarantee.

D. Improvement Approval by City Engineer. The subdivider shall cause plans to be developed and all improvement work to be completed in accordance with the provisions of this chapter and subject to the approval of the city engineer. (Ord. 441 § 1, 1988)

The subdivider shall install improvements in accordance with the general requirements set forth in this chapter provided that the city engineer may require changes in typical sections and details if unusual conditions arise during construction to warrant such change in the interest of the town, such changes to be at the expense of the subdivider.

A. Utilities Constructed Prior to Surfacing Streets. All underground utilities, sanitary sewers and storm drains installed in streets, service roads, or highways shall be constructed prior to the surfacing of such street, service roads, or highways. Service connections for all underground utilities and sanitary sewers shall be placed at such a length as to prevent the necessity for disturbing the street or alley improvements when service connections thereto are made.

• B. Street improvements.

  1. Pavement design shall be as follows:

a. Structural Design. The structural design of the roadbed includes the determination of the thickness and type of subbase, base and surfacing to be placed over the basement soil according to an accepted method used by the city engineer, who shall specify the structural design for the streets in accordance with their classification;

b. Soil Tests. The subdivider shall, at his expense, make tests of the soil over which the surfacing and base is to be constructed and furnish the test reports to the city engineer for use in determining a preliminary structural design of the roadbed. After rough grading has been completed, the city engineer may require the subdivider to have additional tests performed to determine the final structural design of the roadbed.

2. Street Intersections.

• a. Street intersections shall be designed to provide reasonable approaches from side streets, and to provide continuous flow of drainage, without overflow from the gutters due to change of direction, warp of street, or gutter grade;

• b. Concrete valley gutters shall be provided to carry drainage across intersections whenever underground drainage facilities cannot reasonably be provided. Valley gutters shall not be permitted across major streets.

C. Structures. Structures shall be installed as deemed necessary by the city engineer for drainage, access and/or public safety. Such structures to be placed to grades and to be of a design approved by the city engineer.

D. Retaining Walls. Whenever a retaining wall is required within a public right-of-way, it shall be constructed out of masonry, brick, rock, reinforced concrete, or other similar nondeteriorating materials, and be of a design approved by the city engineer.

E. Sidewalks, Curbs and Gutters. Twenty-four-inch wide flat concrete gutters shall be installed on both sides of streets having grades of up to five percent. Twenty-four-inch wide rolled concrete curbs shall be installed on both sides of streets having grades in excess of five percent. Sidewalks or pedestrian paths shall be installed as required by the city engineer.

F. Sewers. Sanitary sewer facilities connecting with an existing sewer system shall be installed to serve each lot and to grades, location, design, and sizes approved by the city engineer. No septic tanks or cesspools will be permitted. Stormwater sewers shall be installed as required by the city engineer.

G. Water. Water mains and fire hydrants of design, layout and locations approved by the city engineer, fire chief, and utility serving the town, and connecting to the water system serving the town shall be installed.

H. Street Trees. Street trees shall be of a type approved by the planning commission and planted in locations approved by it.

I. Street Signs. Street signs shall be of a type approved by the city engineer and installed in locations approved by him.

J. Underground Utilities. All telephone, electric wires or cables, cable TV or other distribution lines to be constructed in and for the purpose of providing service to any subdivision shall be placed underground. All transformers and electrical equipment used and maintained in such subdivisions in connection with the distribution lines shall be installed in underground vaults.

K. Street Lighting. Adequate street lighting shall be provided and dedicated to the town in all new subdivisions and shall meet the following:

1. Standards. Street lighting shall be accomplished by the installation of metal standards and luminaires of a type and size to meet with the approval of the city engineer;

2. Power. Power to electroliers shall be supplied through one and one-half-inch minimum underground conduit. Overhead wires shall not be permitted;

   3. Spacing and Size. Spacing of electroliers and type and size of luminaires shall be as approved by the city engineer.

• L. Traffic Control Devices. The subdivider shall furnish and install such traffic control devices within the subdivision as may be recommended by the chief of police, and as specified by the city engineer.

M. Slope Planting and Erosion Control. All exposed slopes resulting from grading operations shall be protected from erosion due to storm water overflow or other causes. Initial protection shall be by seeding with approved plant materials. Permanent protection shall be by planting with shrubs and trees of species approved by the planning commission. (Ord. 441 § 1, 1988)

The subdivision shall be protected from inundation, flood, hazards, sheet overflow and ponding stormwater, springs and other surface waters. The design of improvements shall be such that water occurring within or flowing onto the subdivision will be carried off such subdivision without injury to any improvements, building sites and structures to be installed on sites within the subdivision, or to adjoining areas. Waters occurring within the subdivision shall be carried to a storm drainage facility or to a natural watercourse by such improvements as may be required by the city engineer. Drainage design within the subdivision shall accommodate anticipated future development within the drainage area. Any off-tract outlet drainage facility required to carry stormwater from the proposed subdivision to a defined channel, or conduit, shall be made adequate for ultimate development in the drainage area.

A. Design Flows. Runoff quantities shall be determined by the modified rational method using basic data supplied by the city engineer for the frequency or occurrence stipulated herein. Drainage facilities directly affecting the proposed subdivision shall have the following minimum capacities:

1. Major drainage channels and conduits shall have sufficient capacity to contain a one-hundred-year frequency of occurrence runoff;

2. Secondary drainage channels and conduits shall have sufficient capacity to contain a twenty-five-year frequency of occurrence runoff;

3. Minor drainage facilities shall have sufficient capacity to contain a twenty-five-year frequency of occurrence runoff.

• B. Design Standards. Design of drainage channels, conduits and appurtenances, shall conform with design standards approved by the city engineer.

• C. Culverts, gutters, and appurtenances shall be as follows:

  1. Minimum Sizes. All storm sewers shall be of a size adequate to carry the design flow, but shall not be smaller than fifteen inches in diameter;

  2. Erosion Control. Drainage within the street right-of-way but outside the surfaced area shall be controlled to prevent erosion by such methods as approved by the city engineer;

  3. Catch Basins. Catch basins shall be of a design approved by the city engineer;

  4. Allowance for Flood Stage. Drainage structures shall account for tidal action and flood stage where applicable.

• D. Open Channels, Conduits, and Appurtenances. Open channels, conduits and appurtenances shall be designed to the satisfaction of the city engineer.

• E. Widths of drainage easements shall be as follows:

  1. Closed Conduits. Minimum widths of drainage easements for closed conduits shall be ten feet. For conduits having a diameter or width greater than four feet, the minimum width of drainage easement shall be equal to the diameter or width of the conduit plus ten feet;

2. Open Channels. The width of drainage easements for natural channels, excavated earth channels and channels lined with concrete shall contain the full width of the channel and the required adjacent access strips.

• F. Subdrainage. Subdrain facilities shall be provided when recommended in the soils report, or as required by the city engineer, and shall be shown on the improvement plans, where applicable.

G. Specifications. All construction materials, methods, tests, and workmanship shall comply with the requirements of the “Atherton Standard Specifications” as recommended by the city engineer. (Ord. 441 § 1, 1988)

A. Survey. An accurate and complete survey shall be made of the land to be subdivided. A traverse sheet in a form approved by the city engineer and showing the mathematical closure, together with complete sets of blue line or black line check prints of the final map, shall be submitted to the city engineer for checking and approval. The traverse of the exterior boundaries of the tract and of each block, when computed from field measurements of the ground must close within a limit of error of one foot to ten thousand feet of perimeter before balancing survey. Wherever the county engineer or city engineer has established a system of coordinates, then the survey shall be tied into such system. All monuments, property lines, centerlines of streets, alleys and easements, adjoining or within the tract, shall be tied into the survey.

B. Monuments. Monuments shall be placed at all lot corners and street corners, shall consist of new galvanized iron pipe not less than one inch in diameter and thirty-six inches long; and shall comply with the following requirements:

1. Each monument shall have a copper plate or disk, securely attached to the top of the monument by a copper dowel or nail not less than two and one-half inches long firmly embedded and marking the exact center. The registered license number of the engineer or surveyor shall be stamped upon the copper plate or disk.

2. In making the survey, the engineer or surveyor shall set monuments in such a manner that the property lines may be retraced in any area of the subdivision with a minimum of difficulty.

3. Where the exterior boundaries of the subdivision are existing street lines and on all interior street lines of the subdivision the engineer or surveyor shall set monuments in the street areas, preferably on the street centerline, and located so as to determine the street lines bounding each block. Due consideration shall be given to visibility of monuments, one from another, for the purpose intended.

4. The monuments in the street areas shall be set so that the tops are at least seven and one-half inches below top of finished pavement grade and enclosed in cast iron receptacles, with cast iron covers of a type acceptable to the city engineer, set flush with the top of finished pavement grade and supported independently of the monuments.

5. Monuments may be set after approval of the final map, but not later than the time of completion of subdivision improvements, provided a cash deposit or approved bond in an amount set by the city engineer is filed with the town, guaranteeing such work.

6. All monuments, and their locations shall be subject to inspection and approval by the city engineer. (Ord. 441 § 1, 1988)