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HomeMy WebLinkAbout11026RESOLUTION NO. 11026 A RESOLUTION APPROVING REVISIONS TO THE SANITARY SEWER DESIGN CRITERIA AND POLICIES MANUAL FOR THE CITY OF PUEBLO BE IT RESOLVED BY THE CITY COUNCIL OF PUEBLO, COLORADO, that: SECTION 1 Upon recommendation of the City Engineer, the revisions to Sections 3.21, 4.1 and 4.8 of the Sanitary Sewer Design Criteria and Policies Manual for the City of Pueblo, Colorado as shown on the documents attached hereto are hereby approved and adopted. SECTION 2. After adoption of this Resolution, a true copy of the Sanitary Sewer Design Criteria and Policies Manual for the City of Pueblo, as revised, shall be maintained on file in the office of the City Clerk for public inspection. Copies shall be made available through the City's Department of Public Works for purchase by the public at a moderate price. SECTION 3. Revisions to the Sanitary Sewer Design Criteria and Policies Manual for the City of Pueblo shall become effective thirty days after passage of this Resolution. INTRODUCED June 11, 2007 BY Randy Thurston Councilperson APPROVED: a #?ESIDEINTof City Council ATTESTED BY: CITY CLERK AGENDA ITEM # Z DATE: JUNE 11, 2007 DEPARTMENT: WASTEWATER DIRECTOR — GENE MICHAEL TITLE A RESOLUTION APPROVING REVISIONS TO THE SANITARY SEWER DESIGN CRITERIA AND POLICIES MANUAL FOR THE CITY OF PUEBLO ISSUE Should the City Council approve various revisions to the Sanitary Sewer Design Criteria and Policies Manual for the City of Pueblo. RECOMMENDATION Approval of this Resolution !7I�:t�3t• The City's Sanitary Sewer Design Criteria and Policies Manual, which was adopted by City Council in May of 1999 and revised in December 2003 and May 2006, governs the design of sanitary sewers, master planning for development, and operation and maintenance of sanitary sewers. Since their adoption and subsequent revisions, certain modifications are necessary to standardize the Vertical Datum used throughout the City. A summary of the key elements of this revision follows: 1. Section 3.2, subsection 3.2.1 — Sanitary Sewer Report The modification of this section will require all subdivision submittals to gather elevation- topography information from the Pueblo County GIS Department in two (2) foot contour intervals I 2. Section 4.1 — Datum The revision of this section will allow for a standardized vertical survey control of North American Vertical Datum 88 or most current NAVD. 3. Section 4.8 — Manhole, Junction Structures, and Cleanouts This article was modified to require that all new manholes constructed outside of dedicated street or alley rights -of -way will be designed with a lock -down type cover. The Wastewater Department solicited input from local engineering firms prior to deveioping the proposed revisions. Attached to the resolution are those sheets from the Sanitary Sewer Design Criteria and Policies Manual that have been changed. Those changes that are deletions are in brackets. Those changes that are additions are underlined. All changes (either additions or deletions) are highlighted in yellow. FINANCIAL IMPACT Most engineer costs associated with these revisions will not change, and in many cases will decrease the cost of design for both the City and private developers. CHAPTER 4. DESIGN CRITERIA Design of both public and private sanitary sewers shall be in accordance with the following minimum design standards and specifications (Article 12- Specifications for Sanitary Sewers) of the City of Pueblo, Colorado: 4.1 DATUM All vertical survey control for sewer design shall be based upon [established City of Pueblo bench marks.] North American Vertical Datum 88 or most current NAVD. 4.2 BENCH MARKS Each sewer project shall have its own vertical control circuit, and each benchmark in the circuit shall be assigned the correct elevation in relation to all other benchmarks in the circuit. The closest benchmark to the proposed work shall be shown on each sewer profile sheet and on each sewer plan sheet on which elevations are shown. 4.3 DEPTH OF SEWERS In general, sewers shall be designed deep enough to drain basements and to prevent freezing. No public mains shall be less than four (4) feet deep measured from the top of pipe unless special protection is provided, (i.e. reinforced concrete encasement, reinforced concrete arch, ductile iron pipe, etc.). No building sewer /service line shall be less than four (4) feet deep in traffic areas without similar special protection listed above except that concrete driveways may be substituted for protection of service lines. 4.3.1 Service connections In designing the minimum depth of public sewers, allowance must be made for the additional depth required to accommodate gravity flows from building sewers and to accept the rise of the service connection. Plat and construction plan notification, along with a separate notice /document (to be recorded) is required for shallow sanitary sewer service lines. 4.4 LOCATION AND ALIGNMENT All public sanitary sewer mains shall be placed within the paved portion of the street when possible. Standard position for locating public sewers, unless some major interference prevents such location, is five (5) feet off of the street centerline and along the centerline of any sewer easement. The alignment in streets less than standard width shall be approved by the Director of Public Works. Whenever a sanitary sewer is placed within an easement, the sanitary sewer easement shall be a minimum of ten (10) feet wide on each side of the sewer main. If the sanitary sewer is to share an easement with another utility additional width may be required. If m CHAPTER 3. PROCEDURES /SUBMITTALS FOR SUBDIVISIONS AND MASTER DEVELOPMENT PLANS 3.1 SUBDIVISIONS Procedures and submittals for subdivisions shall be in accordance with the Application, Review, and Approval Process Manual for Subdivisions, November 2002, and as same may hereafter be amended. 3.2 MASTER DEVELOPMENT PLANS 3.2.1 Sanitary Sewer Report The Petitioner shall prepare a Sanitary Sewer Report in accordance with criteria as follows: [The Report shall identify on a United States Geological Survey (USGS) Map —Scale 1 to 24,000 -the gravity drainage basin or basins incorporating the proposed site and the service area boundary for the City's wastewater treatment plant.] The gravity drainage basin or basins incorporating the -proposed contour. intervals. The Report shall address the needs of the entire sewer drainage basin. This basin will be designated by the Director of Public Works. The Report shall discuss and analyze areas upstream of the site, within the gravity drainage basin, that would impact a trunk line or interceptor within the site. The existing wastewater system and the impact on that system by the proposed development shall also be addressed. The Sanitary Sewer Report shall provide a plan for anticipated improvements. All sanitary sewer reports shall be typed on 8.5" x 11" paper and neatly bound in a folder, which clearly identifies the development. A copy of the general location map and a master sanitary sewer plan shall be included in a folder pocket at the back of the report. The Report shall be transmitted with a cover letter prepared by the Professional Engineer responsible for. the preparation of the report, describing the project, noting any special conditions or problems encountered on the site, certifying that the sanitary sewer report was completed under his/her supervision in accordance with the City of Pueblo's sanitary sewer design criteria and policies, and that the design is in conformance with the City approved master plan for the basin, if one exists. The cover letter shall identify any modification to the criteria that may be requested. The final report shall be signed and stamped by the Professional Engineer responsible for the preparation of the report. Two copies of the report are required upon submittal, one of which will be returned to the Engineer with comments or approval. If corrections or changes are required for approval by the City, two revised copies of the report, with all corrections or;changes made, shall be submitted to the City for approval. Incomplete reports will not be accepted for review. The Report shall include but not limited to: 16 4.7.1 Slope of Sewers All sewers should be designed to transport average wastewater flows at mean velocities of two feet per second based on the appropriate roughness factor. The slope between manholes shall be uniform. The slope for sewer mains shall not be less than 0.40% unless the Engineer can demonstrate why a lesser grade is necessary and as approved by the City. The required minimum velocity shall be 2.0 feet per second (fps). The desired minimum velocity is 3.0 feet per second. The desired maximum velocity is 9.5 feet per second. Sewers designed to carry an average design flow of less than 0.1 cubic feet per second shall not be installed at a slope of less than 0.6 ft /100 feet. 4.7.2 Hydraulic Jumps Hydraulic jumps may occur in manholes when the slope of the upstream pipe is greater than the downstream pipe. Care shall be exercised to avoid hydraulic jumps in conduits. When unavoidable, structures shall be designed per Figure 3 and submitted with calculations for approval. 4.7.3 St�Grades/High Velocities In the case of sewers where the slopes are such that over 15 percent grades are used or the flow velocity exceeds 9.5 feet per second, special provisions shall be made to prevent displacement of pipes and manholes by erosion and hydraulic forces. Such protection (i.e. pipe anchors, special manholes, etc.) shall be shown on detail drawings and approved hy the Director of Public Works. 4.8 MANHOLE, JUNCTION STRUCTURES, AND CLEANOUTS Manholes shall be installed at the end of each line, at all pipeline intersections, changes in grade, size, alignment (except curvilinear sewers), and at distances not greater than those listed in Section 4.8.5 below. For curvilinear sewers, manholes must be placed at all intersections, changes in grade, changes in size, and at distances not greater than 400 feet. Manholes must also be provided at all points of reverse curve, or where required by the Director of Public Works. Manholes must be located to allow unassisted access by maintenance vehicles which range in size from %2 ton to 2 '/2 tons. All manholes located outside of dedicated street or alley rights -of- way will be designed and constructed with a [bolt] lock down type cover as approved by the Director of Public Works. Lines and manholes located in areas where access, in the opinion of the Director of Public Works, is not possible, will not be approved for construction. 24