SECTION: 33 40 00 STORM DRAINAGE UTILITIES

1. JBLM Stormwater Design Guidance available at the JBLM Stormwater Website.
2. UFGS SECTION 33 40 00  STORM DRAINAGE UTILITIES
3. Underground Injection Control (UIC) program: Chapter 173-218 WAC; See also JBLM Stormwater Design Guidance on UIC wells.
4. WA State Department of Ecology Stormwater Management Manual for Western Washington and/or WSDOT Aviation Stormwater Design Manual, as applicable. 
5. Permit No. WAS-026638, Stormwater Discharges from Small Municipal Separate Storm Sewer System (MS4), individual permit to JBLM
6. Permit No. WAR05000F, Nationwide Multi-Sector General Permit (MSGP), Discharges from Industrial Facilities.
7. 2022 Construction General Permit (CGP) | US EPA, Discharges from Construction Activities for sites disturbing over 1 acre.

1. Use the JBLM Stormwater Design Guidance to ensure permit compliance. The LID form is required for all new stormwater facilities. See the JBLM Stormwater website for guidance documents.
2. Registration of all proposed UIC wells must be completed 60 days prior to construction. The stormwater program manager must be contacted during the design phase in order to complete registration.
3. Stormwater Management (SWM) Systems.
   1. The Government’s Consultant or Contractor designers are responsible for design, development, and installation of all stormwater facilities at their respective sites.
   2. Joint Base Lewis-McChord (JBLM) has been issued a Small Municipal Separate Storm Sewer System (MS4) permit (WAS-026638) for stormwater discharges. The permit requires any new development or redevelopment disturbing more than 5,000 square feet to develop a Stormwater Site Plan (e.g. Stormwater Report or Drainage Plan). Use the JBLM Stormwater Design Guidance document to ensure MS4 permit compliance. The Washington Department of Ecology Stormwater Management for Western Washington (SWMMWW) or Aviation Stormwater Design Manual shall be used for BMP selection. The Drainage Plan or Site Plan shall be submitted to the JBLM Water Systems Manager and Environmental Stormwater Program Manager for review.  Guidance documents are available from the PW Environmental Division Stormwater Program website to assist the designer in meeting the permit requirements.
   3. Management of stormwater, prioritizing low-impact development practices, must be identified in initial site plans and integrated into other project aspects water security (i.e. pollution reduction and groundwater recharge) and climate resiliency goals of the installation. Design stormwater systems to maximize on-site management (dispersion, infiltration, etc.) while meeting water quality treatment.
   4. Design and size stormwater facilities to accommodate stormwater runoff from all site development surfaces and all runoff from buildings in conformance with the of the SWMMWW (use of the most recent edition is preferred).  Design goals should be to reduce or eliminate offsite stormwater flows and restore the pre-development hydrology of the project area. Designs must meet all of the requirements below.
      • The designs must comply with Section 438 of the Energy Independence and Security Act (EISA) by following NPDES MS4 Permit No. WAS-026638.
      • Fence all standing water facilities with side slopes exceeding 3h:1v for safety.
      • Within housing, commercial, and organizational areas, ponds cannot be constructed with side slope exceeding 3h:1v or deeper than 2.5 feet.
      • All ponds, swales, or other like stormwater features must be vegetated and/or have amended soils added to provide appropriate function. Complete all standing water facilities with a minimum of 6 inches of topsoil (or minimum specified in the SWMMWW) and plantings appropriate for the pond function. Topsoil must exceed 5% organic content and have pH levels between 6.0 and 8.0.
      • All ponds, swales, or other like stormwater features shall blend with project landscaping to the maximum extent practicable.
      • Storm drain lines and branches within the site shall be polyvinyl chloride (PVC) plastic, ductile-iron, CPEP, or HDPE pipe.
      • Infiltration rates (including topsoil and vegetation), amended or on-site soils mixes, and seed mixtures should all be addressed in the design.
      • Existing native vegetation, especially trees and shrubs, shall be retained and incorporated into the stormwater management design to the maximum extent feasible.
   5. Onsite treatment and infiltration: Use the SWMMWW design standards and requirement. Conduct on-site soil tests in conformance with standard engineering practices per the SWMMWW. Use the soil tests to determine a short-term infiltration rate. Once determined, apply appropriate factors of safety in conformance with standard engineering practices to the short-term infiltration rate to arrive at a long-term design infiltration rate based on site conditions, in conformance with the designer’s professional opinion and discretion, and the approval of JBLM PW, prior to full design. Include detailed information in the design regarding amended soil mixtures, soil depths, vegetation requirements and seed mixtures for all stormwater management features.
      • Stormwater infiltration methods that are small, distributed throughout the project site, and as visually unobtrusive as possible must be assessed for feasibility prior to selection of large or underground facilities. Prioritize BMPs such as dispersion, bioretention, or infiltration with treatment soils that meet JBLM standards and water quality goals for 6 PPD-q removal.
      • Use sheet flow runoff to infiltration features to the maximum extent practicable. If feasible, incorporate vegetative filter strips for water quality treatment. Consider safety when sheet flowing large amounts of runoff.
      • If runoff is proposed to be piped directly to an infiltration trench, an access / maintenance point is required at both ends. Either catch basin / yard drain or cleanout is acceptable. Catch basin / yard drains require 6” minimum sump below outlet pipe invert. Cleanouts shall be 6” minimum diameter and connected using at 45-degree tee (see 2019 SWMMWW Figure V-5.8 for detail view).
   6. The use of underground injection control is allowable only when all other flow control BMPs are considered infeasible per SWMMWW infeasibility criteria. Underground injection facilities must meet the requirements of Chapter 173-218 of the Washington Administrative Code (WAC) Underground Injection Control (UIC) Program. Request approval with supportive documental (e.g. drainage plan/report and registration documentation) from PW Environmental Stormwater program during the design process. Registration with Ecology is required 60 days prior to any construction of UIC facilities.
   7. Low-impact development techniques shall comply with the Low Impact Development Technical Guidance Manual for Puget Sound Erosion and Sediment Control. Provide appropriate erosion and sediment controls on all construction sites that will have ground disturbance. Proper implementation and maintenance of appropriate best management practices (BMPs) is critical to control any adverse water quality impacts from construction activities adequately. Discharges must not violate the state’s surface water quality standards (WAC Chapter 173-201A) and groundwater quality standards (WAC Chapter 173-200).
   8. Volume II, Chapter 4 of the Stormwater Manual provides standards and specifications for BMPs during construction that are approved for use on JBLM. Consider other BMPs with proper review and approval by JBLM PW.
   9. Erosion and sediment control measures at construction sites less than 5,000 square feet may be documented in the Environmental Protection Plan.
   10. Submittal of a site-specific Storm Water Pollution Prevention Plan (SWPPP) is required for construction activities that will have a land disturbance of 5,000 square feet or more. For sites that disturb an acre or more, an EPA Construction General Permit (CGP) NOI is ALSO required. Templates for SWPPPs are available on the JBLM Stormwater Website. Stormwater Pollution Prevention Plan shall be approved by JBLM PW Environmental Division (usarmy.jblm.id-readiness.list.environmental-project-review@army.mil) no later than one (1) week prior to construction. Anticipate a 2 week review for each submittal or re-submittal.
   11. Bioretention Facilities: In addition to following the Temporary Erosion and Sediment Control (TESC) guidance in SWMMWW BMP T7.30, BMP C103: high visibility plastic fence shall be implemented during construction around bioretention facilities until final stabilization has been met in accordance with the National Pollutant Discharge Elimination System General Permit For Discharges from Construction Activities definition in section 2.2.14.b.

• Site maps must meet requirements of the JBLM Stormwater Design Guidance.  
• All stormwater facility and TESC BMPs must be labeled using the appropriate number from the Stormwater Management Manual for Western Washington or Aviation Stormwater Design Manual.
• Abandoning Existing Stormwater Pipe
  Abandoned pipes shall be removed. However, if it is not practical to remove the pipe, the pipe can filled completely with a controlled-density fill (CDF) and the pipe ends can be plugged as specified in per WSDOT Standard Specifications. If an abandoned pipe is filled with CDF, contractor shall mark locations of CDF abandoned lines on construction as-built plans. Construction as-built plans shall be submitted to JBLM DPW Geospatial Support Office (usarmy.jblm.id-readiness.list.dpw-geospatial-requests2@army.mil).
• Abandoning Existing Manholes
  Where it is required that an existing manhole be abandoned, the Structure shall be broken down to a depth of at least 4 feet below the revised surface elevation, all connections plugged, and the manhole filled with sand and compacted to 90 percent density. Debris resulting from breaking the upper part of the manhole may be mixed with the sand subject to the approval of the Engineer. The ring and cover shall be salvaged, and all other surplus material disposed of.
   
  Recommended Manning’s “n” values for Pipe Flow design. 

  Pipe Material	Manning's "n" Coefficient
  Concrete pipe and CPEP-smooth interior pipe	0.014
  Helical 2 2/3 x ½-inch corrugation and CPEP-single wall	0.028
  Spiral rib metal pipe and PVC pipe	0.013
  Ductile iron pipe	0.012
  Ductile iron pipe cement lined	0.014
  High density polyethylene pipe	0.009

• WSDoT Standard Plans: https://www.wsdot.wa.gov/Design/Standards/default.htm
• WSDoT Standard Specifications: https://www.wsdot.wa.gov/Publications/Manuals/M41-10.htm

 
 
Applicable Points of Contact
Design Standards