13-05-001

Division 13-05-001
Engineering Design Reports

Sections:

13-05-001-0001 Water and Sewer System Design Report

13-05-001-0003 Storm Drainage Report

13-05-001-0001 Water and Sewer System Engineer Design Report

A. A water and sewer design report, sealed by a registered professional engineer licensed in Arizona, is required for all new subdivisions, public water or sewer system additions or modifications, new roadways, or as determined by the City Engineer. This report is to assure that the engineer has dealt with water and sewer systems design and has offered solutions which conform to the approved preliminary plat or site plan and this title.

1. If, in preparation of the report, the engineer finds that substantial changes from the approved preliminary plat are required to produce an economical development, a revised preliminary plat shall be prepared.

a. A forced engineering solution conforming to an approved preliminary plat is not acceptable.

b. The report should be prepared in conjunction with the approved preliminary plat and/or construction drawings until all design problems are worked out.

2. The report is required with the initial construction plans submittal. The reports must be approved prior to the approval of the construction plans.

B. Water distribution systems shall be designed to adequately satisfy the requirements of Division 13-09-003, Water System Design. The engineer should investigate the maximum daily rate and the maximum hourly rate plus the required rate for fire protection, to determine which will govern the design. Consideration of future requirements and extensions shall be included in the report. Water lines shall be sized to maintain water pressure as required in Chapter 13-09 and shall adhere to all general requirements including valves, blow-offs, and fire hydrants. All calculations should be shown to justify the design.

C. Considerations of sewage flow shall include investigation of volume, strength, and types of flow to be collected by the system and the impact of development on the existing downstream system. The engineer shall account for future requirements and extensions if the design only covers part of the area to be served. All general requirements, as listed in Division 13-09-004, Sewer System Design, shall be adhered to. Calculations concerning pipe sizing, velocity and grades shall be shown for all lines. Requirements concerning loading on pipes should also be considered as part of the overall design. (Ord. 2017-22, Rep&ReEn, 07/05/2017)

13-05-001-0002 Soils Report

A geotechnical soils report prepared by a registered professional engineer licensed in Arizona, specializing in geotechnical engineering, is required with the initial construction plans submittal of street structural section design or slope stability analysis.

A. The soils engineer shall address the following problems: shrink-swell potential, ground water, wetness, depth of rock, erosion, flood hazard, allowable velocity in earth drainage channels, bearing capacity, corrosion potential, organic layers, ease of excavation, and other pertinent issues. Correlated "R-values" that are used in the pavement structural section design should be determined from soil samples containing the highest amount of clay (PI values).

1. If higher PI values are reported but not considered in the determination of the correlated R-values, the engineer shall provide recommendations for removal of these materials, including specific areas of removals that must be reflected on the approval civil plans.

2. If cut and fill slopes are proposed which exceed those allowed by City standards and/or Title 4, Building Code, a slope stability analysis establishing maximum stable slope grades must be included.

a. If problem areas are found, further analysis may be required in those specific areas.

B. If, in preparation of the report, the engineer finds that substantial changes from the approved preliminary plat are required to produce an economical development, he shall prepare a revised preliminary plat.

C. Forced engineering solutions to conform to an approved preliminary plat are not acceptable.

D. The report should be prepared in conjunction with the approved preliminary plat and/or construction drawings until all design problems are worked out. (Ord. 2017-22, Rep&ReEn, 07/05/2017)

13-05-001-0003 Storm Drainage Report

A. A drainage report, prepared in accordance with the requirements of the Stormwater Design Regulations, is required and must be approved prior to approval of the construction plans.

1. If, in preparation of the report, the engineer finds that substantial changes from the approved preliminary plat are required to produce an economical development, he shall prepare a revised preliminary plat.

a. Forcing engineering solutions to conform to an approved preliminary plat is not acceptable.

2. The report should be prepared in conjunction with the approved preliminary plat and/or construction drawings until all design problems are worked out.

B. If low impact development (LID) is proposed in the right-of-way, the following shall be addressed to the satisfaction of the City Engineer and the Public Works Section Head:

1. Measures provided to ensure the preservation of adjacent pavement section, or other associated infrastructure, as the result of infiltration and/or standing water associated with an IMP.

2. A detailed operations and maintenance manual that, at a minimum, shall include a narrative describing the purpose and function of the IMP, required maintenance activities, and needed inspection activities. (Ord. 2017-22, Rep&ReEn, 07/05/2017)