Arcadia Municipal Code Part 6 Design Standards

All plans required under the provisions of this Chapter for the construction of main line and house connection sewers shall conform to the standards of design prescribed by this Chapter. Plans required for all other sewer construction or installation under the provisions of this Chapter shall conform to the standards of design on file in the office of the City Engineer.

Main line sewer pipe shall have an inside diameter of not less than eight (8) inches and shall have sufficient capacity to carry sewage from the area tributary thereto when computed upon the following basis:

(1) For residential areas, per acre—0.004 cu. ft. per sec

(2) For light industrial areas, per acre—0.016 cu. ft. per sec

(3) For heavy industrial areas, per acre—0.021 cu. ft. per sec

(4) Individual plant capacities shall be the determining factor where they exceed the above coefficients.

The City Engineer shall determine the classifications set forth in subparagraphs (1), (2), (3) and (4) of this Section, and shall approve any modification thereof.

A main line sewer shall be designed to provide a minimum velocity of two (2) feet per second for pipes flowing half full, except that the City Engineer may approve a lower velocity if he finds that such a gradient is unobtainable.

The slope of the sewer shall be shown on the plans in feet of fall per l00 feet of horizontal distance expressed as a percentage. Slopes used expressed in percentages shall be divisible, without remainder, by four (4) in the hundredth column. For example, 0.16% complies with this subsection.

The standard depth for main line sewers in residential districts shall be seven and one-half (7-½) feet and in business districts shall be sufficient to provide a house connection depth of ten and one-half (10-½) feet for areas where no ground water is present. Standard depth for six (6) inch house connection shall be six (6) feet in residential districts, and ten and one-half (10-½) feet in business or apartment house districts respectively, below the curb grade at the curb or property line. Where ground water is present the depth for residential main line sewers shall be sufficient to provide for a house connection with a minimum depth of at least five (5) feet below the curb grade at the property line. Exceptions to the above minimum may be made only on approval by the City Engineer.

Manhole structures shall be placed in the main line sewer at all changes of alignment and gradient. The maximum distance between structures shall be not more than three hundred fifty (350) feet. All structures shall be designed according to the standard drawings for structures on file in the office of the City Engineer.

Main line sewers shall be located on the center lines of streets or alleys except on major highways where separate sewers shall be located in the roadway six (6) feet from either curb line. Exceptions to these standard locations may be made only upon approval of the City Engineer.

End structures shall be located ten (10) feet up grade from the down grade lot line of the last lot served, unless greater length is necessary to serve the property.

Six (6) inch house connection sewer service shall be provided in the street for each lot, and the depth shall be sufficient to provide a connection to the lowest and farthest point of the lot with a cover of one foot and a grade of not less than two percent (2%). Any exception to this requirement may be had only upon approval of the City Engineer.

Pipe used for sewers shall be as follows:

(1) Standard strength for sewers not more than ten (10) feet in depth from the surface to invert.

(2) Extra strength for sewers more than ten (10) feet and not more than twenty (20) feet in depth.

(3) Reinforced with concrete cradle or concrete encasement for sewers more than twenty (20) feet in depth.

(4) Encased in concrete or placed inside of steel pipe backfilled with sand for sewers under railways.

(5) Reinforced as required by the City Engineer for sewers under large conduits or other structures.

Soil conditions, particularly in areas known to have high ground water tables, rock, or filled ground, shall be prospected and the results shown on the profile.

All substructures which will be encountered in the construction or which will be installed as part of the improvement shall be shown and designated on the plan. Large substructures which require special treatment in the design of the sewer shall also be shown on the profile. The permittee shall submit to the City Engineer a statement from each utility company having substructures in the affected area, certifying that the location and size of such structures, as shown on the plans, are the same as shown upon their records.

A system of bench marks on U.S.G.S. datum and adequate to construct the work shall be shown on the profile.