Division 2. Engineering and Design Requirements
Chapter 5.15
DESIGN CALCULATIONS AND PLAN PREPARATION
Sections:
5.15.020 Size of plans and data required.
5.15.040 Easements for future extensions.
5.15.050 Flood control approval.
5.15.070 Construction permits.
5.15.010 Design calculations.
When requested to do so by the District, the job engineer shall submit design calculations for District review and approval. Design calculations shall be submitted in duplicate and shall be in a neat, acceptable form and shall indicate the date, signature of the job engineer and his stamp with his State of California registration number and expiration date.
Calculations for sewers shall be presented in tabular form and shall include the following information for each section of sewer: terminal manhole designation, ground elevations at terminal manholes, incremental and cumulative tributary population, incremental average and maximum domestic sewage flow, incremental infiltration allowance, cumulative design flow, invert elevations of terminal manholes, length of sewer run, and sewer size, slope, capacity and velocity. Design calculation for pumping stations shall include soils data, structural design calculations, hydraulic calculations including the basis for average and peak flows, calculations for wet well volume, curves indicating force main characteristics, and individual and combined pump head capacity curves.
All calculations shall be accompanied by a small scale map showing and identifying proposed sewerage facilities and tributary areas, etc. [Ord. 2014-2 (Att. § 3-01).]
5.15.020 Size of plans and data required.
Sheet sizes for plans for all sanitary sewerage facilities shall be 22 inches by 34 inches, unless otherwise specifically approved in advance by the District, and the plans shall include as a minimum the following information and data:
(1) General. The plans shall show the name of the project, subdivision, and each sheet shall bear the job engineer’s signature and registration stamp with expiration date. Each map and plan sheet shall have a north arrow, appropriate scale or scales and date of preparation indicated thereon.
(2) Sewer Plans. The sewer plans shall show the true horizontal relationship between the proposed sewer improvements and the existing and/or proposed field conditions, including all existing or proposed utilities and other facilities in accordance with available information (see SD5MCC 5.55.020). Plans shall include sewer line sizes and designations and shall show all structures and their respective numbers, the property lines and corners adjacent to the sewer alignment, laterals and ties to property corners, all necessary required stationing, horizontal curve data and street names. Horizontal scale must be 20 feet to the inch with a vertical scale of five feet to the inch unless another scale is specifically permitted by the District.
(3) Sewer Profiles. The sewer profiles shall show the vertical relationship between the sewer line invert and the ground surface at the time of sewer construction and the finished ground and/or paving surface. The sewer line size, pipe type and pipe class shall be shown between each pair of consecutive structures on the profiles. Sewer profiles shall also show all existing and/or proposed utilities and/or other facilities in accordance with available information (see SD5MCC 5.55.020) which cross the alignment of the sewer and shall accurately indicate clearance when less than 12 inches. Sewer profiles must be prepared at the same horizontal scale as the plans and a vertical scale of five feet to the inch, unless another scale is specifically permitted by the District.
(4) Easements. All existing and proposed easements and rights-of-way shall be shown on the plans.
(5) Vicinity Map. A small scale vicinity map showing the location of the development within the town or city, together with the streets and downstream sewer, shall be shown on the first sheet of the plans.
(6) Location Map. A location map at a scale of 100 feet to the inch shall be included on the first sheet of the plans showing the entire development, the overall sewer layout and appropriately indexing each plan sheet.
(7) Line Stationing. Each sewer line with a separate designation shall be stationed continuously upgrade from 0+00 at its point of connection to another line.
(8) Ties to Existing System. Horizontal and vertical ties to the existing District sewerage system shall be indicated on the plans.
(9) Structure Numbers. Manholes, rodding inlets, and all other sewer structures shall be numbered or stationed consecutively upgrade by type of structure. The structure number shall appear on the plans and profiles whenever the structure is shown or referred to.
(10) Side Sewer Locations and Elevations. All side sewers or laterals shall be shown on the plans with ties given to nearby property corners. The elevation of the lateral at the property line shall be shown on the plans and staked in the field by the job engineer.
Where properties are fronting on a cul-de-sac, the laterals for these properties shall be connected to a manhole. Normally, the lateral shall be shown to a point 10 feet from the lower lot corner at the property line on hillside lots (three-plus percent slope), and to the approximate center of the lot in relatively level terrain. The job engineer may locate laterals to fit building conditions, but the plans must show proper ties, and the completed lateral must be permanently marked with an “S” on the curb or a stake and accurately shown on the record drawings.
(11) Elevation Datum. The elevation datum used shall be USC and GS mean sea level (National Geodetic Vertical Datum NGVD). The plans shall include a note indicating the elevation datum and describing the location of one or more benchmarks in the area of the work.
(12) Standard Notes. In addition to any other notes which may be appropriate or required, the following notes shall be included on all plans:
(a) “All sewer construction shall be in accordance with the Sanitary District No. 5 Standard Specifications and Drawings.”
(b) “The Contractor shall notify the District 48 hours prior to starting any sewer work.”
(c) “For any work in a public street, the Contractor shall obtain an encroachment permit from the agency having jurisdiction.”
(d) “The locations of utilities shown on these plans are approximate only, and it is the Contractor’s responsibility to verify locations and depths with appropriate agencies or by potholing. The Contractor shall call USA Underground Service Alert at least 72 hours prior to commencing work.”
(e) “The Contractor shall pothole all underground utilities and sewers prior to any trenching operation.”
(f) “The Contractor shall notify the District immediately of any conflict between sewers and other underground facilities.”
(g) “The Contractor shall shore all excavations in accordance with applicable safety orders.”
(h) “All sewer laterals shall be a minimum 4 inches inside diameter and shall have a minimum slope of 1.0% and minimum depth of cover at the property line of 3.0 feet (measured from the top of curb), unless otherwise noted on these plans.” [Ord. 2014-2 (Att. § 3-02).]
5.15.030 Rights-of-way.
Rights-of-way define and establish the rights for the District to maintain a sewer facility in the location designated by the job engineer (see SD5MCC 5.05.050). When main sewers are to be installed outside of public street rights-of-way in subdivisions, the required easements shall be shown on the subdivision final map and shall be granted to the District in a separate deed of easement. Outside of subdivisions, when sewers are to be installed on private property, an easement must be granted to the District and the easement description and required easement map shall be provided to the District by the job engineer, along with the name and address of the property owner or owners of record. Unless otherwise specifically approved by the District, public sewer permits will not be approved nor will any work be permitted to proceed until the District receives, approves and accepts and records all required easements.
(1) Easement Descriptions. Easement descriptions shall provide legal metes and bounds description of all easements to be granted. The preamble of the easement description shall read as follows:
AN EASEMENT for the construction and maintenance of sanitary sewer facilities and appurtenances, together with the right of ingress and egress, over, on or under the following described property:
(2) Easement Maps. The easement map shall show the entire parcel over which the easement is granted, and all necessary survey ties, courses and distances, the point of beginning of the easement description, the last names of each grantor, the name of the sewer main extension involved, a north arrow, map scale, and the job engineer’s signature and registration stamp with expiration date. Bearings and distances of easement courses shown shall conform to those given in the easement description. Two black line prints of the easement map shall be submitted (for each grantor involved).
(3) Easement Deeds. After approval of the required easement map and description, the permittee shall prepare the necessary easement deed on an appropriate form and furnish the District with a properly signed and notarized deed of easement for recordation by the District. [Ord. 2014-2 (Att. § 3-03).]
5.15.040 Easements for future extensions.
Easements shall be granted to the District through the property to serve the upstream property in all cases where future extensions of sewer lines could be required beyond the property being sewered. Such easements shall be included on the construction plans where there is any doubt as to the ability to properly serve the ultimate service area. [Ord. 2014-2 (Att. § 3-04).]
5.15.050 Flood control approval.
In the event that a proposed sewer is to cross a creek, storm water channel, conduit, structure or drainage course under the jurisdiction of the Marin County Flood Control and Water Conservation District, a detailed large scale profile of the crossing shall be incorporated in the plans with approval of the Flood Control District, County and/or city of jurisdiction prior to approval of the plans by the District. [Ord. 2014-2 (Att. § 3-05).]
5.15.060 Soils investigation.
Due to the inherent hazards involved in excavation, trenching, and pipe laying in certain common soil formations within the District, the right is reserved to require geological investigation and report prior to the approval of construction plans. In general, locations on steep side hills, locations in areas of established instability, locations in areas of bay mud or filled marshland, spring or seepage areas, or areas where concentrated or unusual development exists or is planned shall be investigated and construction controlled by the recommendations contained in the soils engineer’s report. The costs of all soils investigations shall be paid for by the permittee. [Ord. 2014-2 (Att. § 3-06).]
5.15.070 Construction permits.
The permittee shall be responsible for securing all necessary construction permits. Such permits include, but are not necessarily limited to, permits from BCDC, the U.S. Army Corps of Engineers, State Department of Fish and Game, Cal/OSHA, Division of Industrial Relations, street or railroad encroachment permits, etc. [Ord. 2014-2 (Att. § 3-07).]