8271-0724-JKA
July 24, 2001
Mr. John Knowles
John Knowles and Assoc., Inc.
P.O. Box 1328
Puyallup, Washington 98371-0197
RE: Timbertec – File No. SPR-00-8271-YL
Review No. 1 of Civil Engineering Plans
Dear Mr. Knowles:
I have reviewed your civil engineering submittal package dated 7/18/01. The plans have been reviewed for compliance with the City of Yelm’s Development Guidelines and DOE Stormwater
Manual. The following comments need to be addressed before approval of these plans.
Sheet C1: Cover Sheet
Please revise the approved for construction signature block. The signature block should read “Development Review Engineer” instead of director of public works. (All sheets)
Please replace the watermain installation general notes with the current approved notes. They are located on page 6-3 and 6-4 of the Development Review Guidelines.
Please replace the sanitary sewer main installation general notes with the current approved notes. They are located on page 7-52 thru 7-54 of the Development Review Guidelines.
Sheet C2: Grading, Drainage, Paving and Erosion Control Plan
Show existing spot elevations on the plan.
Please add surface flow arrows to the plan. Does the existing asphalt pavement have sufficient grades to convey surface water to the proposed catchbasins and their locations?
Add proposed spot elevations to the extruded curb and ADA accessible stalls.
Revise erosion note #5 to specify your compaction standards and who is approving the structural fill. The UBC code is only used within the building envelope or 5 ft outside of the building.
Revise grading note #1. Specify the location of the proposed on-site stockpiled material and remove the words “as directed by city.”
Add the outlet pipe invert elevation to the plan. Grading note #9 refers to sheet C6 however the invert does not appear on this sheet.
On grading note #21 add the word ADA between provide and accessible.
Sheet C3: Water and Sewer Plan
Revise note #1 to see standard detail 7-2 on sheet C5.
Revise note #5 to list step tank manufacturer and model number or direct contractor to submit tank cut sheets to City of Yelm for approval before installation. Revise the Orenco step
pump to be model 20 instead of 10.
It appears that the step tank inlet inverts are mislabeled by 100 ft. Please revise these as required.
Please specify what type of water service line is to be installed and the location for installation.
Revise water note #D to list what is required to upgrade existing hydrant to current codes.
Please show a water hose bib within 50 ft. of the step tank location.
The backflow prevention device will require a “hot box” per regulations. This will require electrical wiring to be installed from the building to the box location.
Sheet C4: Details
Replace water standard detail 6-3 with the current water meter detail.
Sheet C5: Details
Replace sewer standard details 7-6, 7-9 and 7-13 with the unmodified standard details.
Sheet C6: Pond Details
Provide structural calculations for the ecology block retaining wall. The calculations are required because the wall is located in the water. Is the retaining wall going to have a
drainage system behind the wall? (i.e. french drain)
Please revise the gravel filter window detail to reflect the detail in the DOE stormwater manual on page 3-4-18, Figure 3-4-5. The base of the gravel filter window should be at the
top of the sediment storage level and the top of berm 1 foot below the max water surface of the wetpond.
The gravel filter window between the wetpond and infiltration pond as shown is ok. Please add a reversed slope pipe from the wetpond to infiltration pond.
Sections B-B and C-C do not match the pond plan view. The pond view has 3:1 side slopes listed and the cross sections show 2:1 on the upper slopes. Revise the plan so these match.
A min. 18” layer of compacted topsoil is required to be placed over the 30-mil pond liner. Please add this information to the pond liner note.
Revise the sheet scale in the title block. I believe it should be 1”=20’.
A fence is required at the maximum water surface elevation or higher, when a pond slope is a wall. In the stormwater report it has been stated that the perimeter property line fence
will be the fence for the stormwater facility. This is the owner choice, however the owner will need to provide the City of Yelm a hold harmless agreement for the liability this may
create without a dedicated fence around the pond.
The pond concept is allowed under the DOE Guidelines, however this design allows floatable debris and sediment into the infiltration pond during 100 year storm events. Please add a
note to the plans stating, “This stormwater pond design allows floatable debris and sediment into the infiltration pond during 100 year events. This stormwater pond design will require
extra maintance to prolong the infiltration ponds ability to discharge water effectively.”
General Comments:
After reviewing the STEP sewer calculations submitted for this project, it appears that you used a different formula than you have requested in the past reviews. Please use the formula
V=1,125+(.75(Q)). According to your submitted information, when utilizing this formula 1,668 gallons is the volume required. Please revise the STEP tank size to accommodate this volume
and resubmit the calculations.
The owner is responsible for a TFC charge of $4,777.50 which is payable at time of building permit issuance.
This project requires improvements along the frontage of this property. The owner has requested and the city has granted a waiver of protest to these improvements. Have you sized the
stormwater facilities to include the roadway frontage improvements in the future? If not how is the runoff to be controlled?
The owner is responsible for a connection fee for the sewer system. This rate will be charged at a rate of $4,850 per 240 gallons of estimated use. At this time, the city is only going
to charge the owner for the estimated use by the existing building. Based on your calculations, the usage is 400 gpd, which is rounded up to 480 gallons. The cost will be $9,700.00
for the connection fee. When the additional building is built the owner is responsible for the additional connection fee.
The applicant must submit fire flow calculations for the existing hydrants and future hydrants. This is a condition of approval.
The owner submitted cut sheets for the oil/water separator, micron filter and proposed structure for the washdown rack. It is still unclear how this washdown unit is operated. The
plans show water connected to the washdown area however no connection exists for the step sewer. Where is the additional water being discharged?
Please review and revise your engineering drawings. When you resubmit your package, please send 2 sets of bluelines and two drainage reports. If you have any questions or comments please
call me at (360) 458-8438 and I will be happy to further assist you.
Respectfully,
City of Yelm Community Development
Jim Gibson
Development Review Engineer
Enc:
Cc: Shelly Badger
Tim Peterson
Cathie Carlson