| Condition |
Status |
Category |
|
Miscellaneous Condition
|
Open
|
|
|
|
|
Miscellaneous Condition
|
Open
|
|
|
|
|
Miscellaneous Condition
|
Open
|
|
|
|
|
Miscellaneous Condition
|
Open
|
|
|
|
|
Miscellaneous Condition
|
Open
|
|
STORMWATER/ EROSION CONTROL:
33. Stormwater design shall be in accordance with the 2012 Stormwater Management Manual for Western Washington as amended in the December, 2014 (The 2014 SWMMWW aka “Ecology Manual”).
34. The applicant shall complete the stormwater flowchart, Figure 3.1, contained in Ecology’s Phase II Municipal Stormwater Permit, Appendix I. The completed flowchart shall be submitted with the preliminary stormwater site plan and highlight the Minimum Requirements (MR) triggered by the project thresholds.
35. NOTE: Areas of disturbance within the public ROW must be included in the project area as part of the stormwater thresholds and calculations.
36. Each section of the TIR/SSP shall be individually indexed and tabbed with each permit application and every re-submittal prior to review by the City. [PMC 21.10.060]
37. Public right-of-way runoff shall be detained and treated independently from proposed private stormwater facilities. This shall be accomplished by enlarging the private facilities to account for bypass runoff; providing separate publicly maintained storm facilities within a tract or dedicated right-of-way; or, other methods as approved by the City Engineer. [PMC 21.10.190(3)]
38. Development and redevelopment projects are required to employ, wherever feasible, Low Impact Development (LID) Best Management Practices (BMPs) to meet the design criteria set forth in PMC 21.10.190, the Ecology Manual Volume I, Minimum Requirement 5; Volume III, Chapter 3; and Volume V, Chapter 5.
39. Preliminary feasibility/infeasibility testing for infiltration facilities/BMPs shall be in accordance with the site analysis requirements of the Ecology Manual, Volume I, Chapter 3, specifically:
- Groundwater evaluation, either instantaneous (MR1-5), or continuous monitoring (MR1-9), during the wet weather months (December 21 through April 1).
- Hydraulic conductivity testing:
i. If the development meets the threshold to require implementation of Minimum Requirement #7 (flow control); or, if the site soils are consolidated; or, if the property is encumbered by a critical area, then Small Scale Pilot Infiltration Testing (PIT) during the wet weather months (December 21 through April 1) is required.
ii. If the development does not meet the threshold to require implementation of Minimum Requirement #7; or, is not encumbered by a critical area; and is located on soils unconsolidated by glacial advance, grain size analyses may be substituted for the Small Scale PIT test at the discretion of the review engineer.
- Testing to determine the hydraulic restriction layer.
- Mounding analysis may be required in accordance with Ecology Volume III Section 3.3.8.
40. Upon submission of the geotechnical infiltration testing, appropriate long-term correction factors shall be noted for any areas utilizing infiltration into the underlying native soils in accordance with the Ecology Manual, Volume III, Chapter 3.
41. If infiltration facilities/BMPs are anticipated, the number of infiltration tests shall be based on the area contributing to the proposed facility/BMP, e.g., one test for every 5,000 sq. ft of permeable pavement, or one test for each bioretention cell.
42. If the proposed project discharges to an adjacent wetland, the applicant shall provide a hydrologic analysis which ensures the wetland’s hydrologic conditions, hydrophytic vegetation, and substrate characteristics are maintained. See Ecology Manual Volume I, Minimum Requirement 8.
43. The proposed project is part of a larger, common plan of development, and includes the use of existing stormwater facilities. The Technical Information Report (TIR) or Stormwater Site Plan (SSP), shall provide supporting documentation and engineering calculations which substantiate the affect of the proposed project in regards to the design assumptions of the existing stormwater facilities. [PMC 21.10.060]
44. At the time of civil permit application, the applicant is responsible for submitting a permanent storm water management plan which meets the design requirements provided by PMC Section 21.10. [PMC 21.10.190, 21.10.060]
- When using WWHM for analysis, provide the following WWHM project files with the civil permit application:
- Binary project file (WHM file extension)
- ASCII project file (WH2 file extension)
- WDM file (WDM file extension)
- WWHM report text (Word file)
45. The submitted project documentation indicates that the existing combined detention-wetpool facility serving adjacent properties to the South will be filled in as part of this proposed development. This facility was designed and constructed to past stormwater regulations using a single event model, Santa Barbara Urban Hydrograph (SBUH) for flow control, and a wetpool sized using ½ of the 2-yr release rate for water quality compliance.
- The applicant shall provide supporting documentation substantiating the 2-yr, 10-yr, and 100-yr release rates of the existing detention facility.
- The upstream basins tributary to the existing detention facility shall be incorporated into the current project’s stormwater model in such a way as to ensure no increase in flow (release rate) to the downstream stormwater system post-project while complying with the requirements of the Ecology Manual for the proposed project.
- The applicant shall provide water quality facilities for the existing upstream basins equal to, or better, than the existing wetpool facility to ensure no degradation of stormwater from the properties to the South.
- Provide a detailed explanation of the analysis in the written technical report, including, but not limited to, assumptions; calculations; discharge rates; stage-storage relationships; recommendations, and any proposed modifications to the existing system.
46. Overflow facilities shall be provided at the low points of the proposed permeable pavement areas to allow safe discharge to the downstream public storm system.
47. The use of permeable pavement(s) will require trench dams where utility pipes cross property lines.
48. Any above-ground stormwater facility shall be screened from public right-of-way and adjacent property per the underlying zoning perimeter buffer requirements in the PMC.
49. Stormwater R/D facilities shall be a minimum of 20-feet from any public right-of-way, tract, vegetative buffer, and/or property line measured from the toe of the exterior slope/embankment of the facility. [PMC 21.10 & DOE Manual, Vol. V, Pg 10-39 and Pg 10-9]
50. The 2-yr, 10-yr, and 100-yr water surface elevation (WSE) shall be shown on the R/D facility cross-section(s).
51. A Stage-Storage Table for the 2-yr, 10-yr, and 100-yr water surface elevations shall be provided on the same civil sheet as the R/D facility cross-section(s).
52. Water quality treatment of stormwater shall be in accordance with the Ecology Manual, Volume 1, Minimum Requirement 6; and Volume 5, Runoff Treatment.
53. If the applicant proposes to use bioretention cells for water quality treatment, the following notes shall be added to the civil design plans:
- “At the completion of the bioretention cells construction, the engineer-of-record shall provide a written statement to the City of Puyallup that the bioretention cells were built per the approved design.”
- “The bioretention soil media (BSM) supplier shall certify in writing that the bioretention soil media meets the guidelines for Ecology-approved BSM including mineral aggregate gradation, compost guidelines, and mix standards as specified in the 2012 Low Impact Development Technical Guidance Manual for Puget Sound. And, if so verified, no laboratory infiltration testing, cation exchange, or organic content testing is required.”
54. Construction of frontage improvements associated with this project will require installation/extension of the stormwater main to accommodate road runoff. The new stormwater main shall be adequately sized to accommodate any upstream basins tributary to main.
55. At the time of civil permit application, all pipe reaches shall be summarized in a Conveyance Table containing the following minimum information and included in the TIR:
Pipe Reach Name
Structure Tributary Area
Pipe Diameter (in)
Pipe Length (ft)
Pipe Slope (%)
Manning’s Coefficient (n)
Design Flow (cfs)
Pipe-Full Flow (cfs)
Water Depth at Design Flow (in)
Critical Depth (in)
Velocity at Design Flow (fps)
Velocity at Pipe-Full Flow (fps)
Percent full at Design Flow (%)
HGL for each Pipe Reach (elev)
56. Due to the widening of Pioneer Avenue and associated flows generated by the project, provide a backwater analysis of the Pioneer Avenue conveyance system considering the tailwater elevation of the Pioneer Avenue ditch as outlined in City Standards Section 204.3. The analysis shall include any upstream basin flows tributary to the pipe outfall.
57. Flows tributary to the existing Pioneer Way ditch shall be evaluated to determine pipe capacity to convey flows through the future frontage improvements.
58. All storm drains shall be signed as follows:
a) Publicly maintained stormwater catch basins shall be signed using glue-down markers supplied by the City and installed by the project proponent.
b) Privately maintained stormwater catch basins shall be signed with pre-cut 90ml torch down heavy-duty, intersection-grade preformed thermoplastic pavement marking material. It shall read either “Only Rain Down the Drain" or “No Dumping, Drains to Stream”. Alternatively, the glue-down markers may be purchased from the City for a nominal fee.
59. All private storm drainage facilities shall be covered by a maintenance agreement provided by the City and recorded with Pierce County. Under this agreement, if the owner fails to properly maintain the facilities, the City, after giving the owner notice, may perform necessary maintenance at the owner’s expense.
60. Erosion control measures for this site will be critical. A comprehensive erosion control plan will be required as part of the civil permit application.
61. A Stormwater Systems Development fee will be assessed for each new equivalent service unit (ESU) in accordance with PMC Chapter 14.26. Each ESU is equal to 2,800 square feet of ‘hard’ surface.
62. Stormwater Systems Development fees are due at the time of site development permit or in the case where no site development permit is required, at the time of building permit issuance for the individual lot(s); and the fees do not vest until the time of site development permit issuance, or at the time of building permit issuance in the case where a site development permit is not required.
63. A Construction Stormwater General Permit shall be obtained from the Department of Ecology if any land disturbing activities such as clearing, grading, excavating and/or demolition will disturb one or more acres of land, or are part of larger common plan of development or sale that will ultimately disturb one or more acres of land.
|
|
Miscellaneous Condition
|
Open
|
|
|
|
|
Miscellaneous Condition
|
Open
|
|
|
|
|
Miscellaneous Condition
|
Open
|
|
|
|
