Design & Construction Standards 

Volume I includes changes in the following sections:

General     Updated EMC references to align with the EMC 14.28 Surface and Storm Drainage code renumbering and minor grammatical revisions.

2-2     Added text: “The CSWGP SWPPP may be submitted to the City for review to meet Minimum Requirement #2 if all Manual requirements are addressed.”

2-3     Added Text: “At minimum, the Construction SWPPP should include narrative and drawings. All BMPs should be clearly referenced in the narrative and marked on the drawings.”

2-4     Added text: “The Construction SWPPP shall be implemented beginning with initial land disturbance and until final stabilization. The construction of sediment control BMPs are one of the first steps in grading. These BMPs must be functional before other land disturbing activities take place.”

2-5     Added notes #11-16 to standard notes

3-18 and 3-19     Changed to 4” Crushed Surfacing Base Course under sidewalks and curbs.

4-4.1(1) 

• Revised language on possible City ownership and maintenance of stormwater facilities serving multiple lots for single family residential short plat projects. This was updated to match the language in EMC 14.28.
• Added in language that the City will not accept ownership or maintenance responsibility for private proprietary detention storage structures. This has been City policy but was added to improve clarity.

4-2.3(1)     Removed galvanized pipe as it contains zinc, which is a water quality concern. Added polypropylene to the list of approved City materials. (Polypropylene is in WSDOT/APWA standards.)

4-2.3(10)     Added Requirements #6-8

4-2.5(1)     Added text to address runoff from flow dispersal trenches, which is not otherwise addressed in the Stormwater Manual.

4-2.7     Added Standard Note #6.

4-4.1(2)7     Added a requirement for City vehicle turnaround radius for publicly maintained stormwater facilities.

4-4.1(3)     Added #2.d. for reference to standard drawings for bioretention, rain gardens, and roof downspout infiltration setback requirements when adjacent to the ROW. (See new Standard Drawings 437 and 438.) Added #3.a. for infiltration facility setbacks to property lines. This is not otherwise addressed in the Stormwater Manual.

4-4.2(4)3     Updated language on stormwater facility fencing requirements to remove a regulatory conflict with EMC 19.40.020.

4-4.2(5)3 & 4     Revised language on requirements for possible City ownership and maintenance of stormwater facilities serving multiple lots for single family residential short plat projects. This was updated to match language in EMC 14.28.

4-4.2(5)     Table No. 26 – Private Stormwater Pumps. Updated the stormwater pump station maintenance table to match updates in DCSS 4-2.3(10) Stormwater Pumps.

4-4.3(2)     Added text to clarify BMP T5.10A.

4-4.3(3) and 4-4.3(4)     Added clarification that compost cannot be used for projects draining to Silver Lake due to nutrient concerns.

4-4.4     This section was updated to reflect changes to EMC 14.28 to align with Minimum Requirement #7 in the Stormwater Manual.

4-4.4(4)     This is a new section to address City requirements for detention facilities that are not otherwise addressed in the Stormwater Manual.

4-5     This section was revised to improve clarity and align with requirements in EMC 14.28.