HomeMy WebLinkAboutSpiker Stormwater Mgmt. Sheet 9-9-2022 9 of 10
CITY OF SPRINGFIELD, OREGON
PUBLIC WORKS DEPARTMENT / Engineering Division Phone: (541) 726-3753 Fax: (541) 736-1021
STORMWATER MANAGEMENT SYSTEM SCOPE OF WORK
----- (Area below this line filled out by Applicant) -----
(Please return to Matt Stouder @ City of Springfield Public Works Engineering; Fax # 736-1021, Phone # 736-1035.)
Project Name: Applicant:
Date:
Land Use (s): Phone #:
Project Siz
(Acres): Fax #:
Approx. Impervious Area: Email:
Project Description (Include a copy of Assessor’s map):
Drainage Proposal (Public connection(s), discharge location(s), etc. Attach additional sheet(s) if necessary:
Proposed Stormwater Best Management Practices:
----- (Area below this line filled out by the City and Returned to the Applicant) ----- (At a minimum, all boxes checked by the City on the front and back of this sheet shall be submitted for an application to be complete for submittal, although other requirements may be necessary.)
Drainage Study Type (EDSPM Section 4.03.2): (Note, UH may be substituted for Rational Method)
Small Site Study – (use Rational Method for calculations)
Mid-Level Development Study – (use Unit Hydrograph Method for calculations)
Full Drainage Development Study – (use Unit Hydrograph Method for calculations)
Environmental Considerations:
Wellhead Zone: Hillside Development:
Wetland/Riparian: Floodway/Floodplain:
Soil Type: Other Jurisdictions:
Downstream Analysis:
N/A
Flow line for starting water surface elevation:
Design HGL to use for starting water surface elevation:
Manhole/Junction to take analysis to:
Return to Matt Stouder @ City of Springfield, email: mstouder@ci.springfield.or.us, FAX: (541) 736-1021
Assessors Parcel #:
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COMPLETE STUDY ITEMS
* Based upon the information provided on the front of this sheet, the following represents a minimum of what is needed for an
application to be complete for submittal with respect to drainage; however, this list should not be used in lieu of the Springfield
Development Code (SDC) or the City’s Engineering Design Manual. Compliance with these requirements does not constitute site
approval; Additional site specific information may be required. Note: Upon scoping sheet submittal, ensure completed form has been signed in the space provided below:
Interim Design Standards/Water Quality (EDSPM Chapter 3)
Req’d N/A
All non-building rooftop (NBR) impervious surfaces shall be pre-treated (e.g. multi-chambered catchbasin w/oil
filtration media) for stormwater quality. Additionally, a minimum of 50% of the NBR impervious surface shall be
treated by vegetated methods. Where required, vegetative stormwater design shall be consistent with interim design standards (EDSPM Section 3.02), set forth by the Bureau of Environmental Services (BES) or Clean Water Services (CWS).
For new NBR impervious area less than 15,000 square feet, a simplified design approach may be followed as specified
by the BES for vegetative treatment.
If a stormwater treatment swale is proposed, submit calculations/specifications for sizing, velocity, flow, side slopes,
bottom slope, and seed mix consistent with either BES or CWS requirements. Water Quality calculations as required in Section 3.03.1 of the EDSPM All building rooftop mounted equipment, or other fluid containing equipment located outside of the building, shall be provided with secondary containment or weather resistant enclosure.
General Study Requirements (EDSPM Section 4.03)
Drainage study prepared by a Professional Civil Engineer licensed in the state of Oregon.
A complete drainage study, as required in EDSPM Section 4.03.1, including a hydrological study map.
Calculations showing system capacity for a 2-year storm event and overflow effects of a 25-year storm event.
The time of concentration (Tc) shall be determined using a 10 minute start time for developed basins.
Review of Downstream System (EDSPM Section 4.03.4.C) A downstream drainage analysis as described in EDSPM Section 4.03.4.C. On-site drainage shall be governed by the
Oregon Plumbing Specialty Code (OPSC).
Elevations of the HGL and flow lines for both city and private systems where applicable.
Design of Storm Systems (EDSPM Section 4.04) Flow lines, slopes, rim elevations, pipe type and sizes clearly indicated on the plan set. Minimum pipe cover shall be 18 inches for reinforced pipe and 36 inches for plain concrete and plastic pipe materials,
or proper engineering calculations shall be provided when less. The cover shall be sufficient to support an 80,000 lb load without failure of the pipe structure.
Manning’s “n” values for pipes shall be consistent with Table 4-1 of the EDSP. All storm pipes shall be designed to
achieve a minimum velocity of three (3) feet per second at 0.5 pipe full based on Table 4-1 as well.
Other/Misc Existing and proposed contours, located at one foot interval. Include spot elevations and site grades showing how site
drains Private stormwater easements shall be clearly depicted on plans when private stormwater flows from one property to another
Drywells shall not receive runoff from any surface w/o being treated by one or more BMPs, with the exception of
residential building roofs (EDSP Section 3.03.4.A). Additional provisions apply to this as required by the DEQ. Refer
to the website: www.deq.state.or.us/wq/groundwa/uichome.hcm for more information. Detention ponds shall be designed to limit runoff to pre-development rates for the 2 through 25-year storm events
*This form shall be included as an attachment, inside the front cover, of the stormwater study
* IMPORTANT: ENGINEER PLEASE READ BELOW AND SIGN!
As the engineer of record, I hereby certify the above required items are complete and included with the submitted stormwater study and plan set.
Signature: Date:
For Official Use Only: