20070404 Shea Carr Doc 090172008 Storm Drainage Report:
The Storm Drainage Report format is typically written following the 1992 Department of Ecology’s requirements (pg 1-3-13) or the 1994 Thurston County DDCM (pg
3-2). The current format does not appear to follow these accepted formats. Please revise.
2. Storm Drainage Report Section 2.0 — Please include information of any wells or on-site drain
fields to be abandoned.
3. Storm Drainage Report Section 3.0 — This section indicates the downstream flow paths but does not address downstream flow issues. The report should review
and/or address any downstream issues that exist and if there are none the report should also state this.
4. Storm Drainage Report Section 3.0 — The site is in the vicinity of Yelm
Creek which has an associated floodplain. The report should review and/or address the location of this site in relation to the 100-year flood plain and flood plain elevations. Please
include the FEMA floodplain map.
5. Storm Drainage Report Section 3.0 — The site is located in a critical aquifer recharge area. The report should review and/or address this issue.
6. Storm Drainage Report Section 4.2 — Please note, if groundwater is within 6 feet of the bottom of the facility (please see comment #8) the hydraulic gradient can no longer be considered
1. Therefore, the computation of the flow through the facility bottom would then be incorrect. The actual flow will likely be variable depending on mounding effects.
7. Storm Drainage
Report Section 4,2 — The proposed infiltration system is a StormTech Chamber. Stormwater infiltration facilities that use pipe are considered underground injection stormwater wells and
require the appropriate design and separation from groundwater per the DOE’s requirements for UIC’s (please note — if the separation from groundwater required for the UIC is less than
6 feet, then the 6 feet required by COY would apply). Further, if this system is proposed, the 2005 DOE Manual will need to be followed rather than the 1992 Manual for all stormwater
sizing calculations. Please either revise the design or follow the requirements for the underground injection stormwater wells.
8. Storm Drainage Report Section 4.4 — The Conditions
of Approval and MDNS require that the bottom of any infiltration facility for storm water discharge shall be located at least 6 feet above the base flood elevation. The City considers
the base flood elevation to be the same elevation at the 100-year flood elevation of the site (+7-344.0). The storm water design does not meet this requirement and additional justifications
or reports were not submitted
supporting this design. Please revise the design or include the necessary supplementary reports.
9. Storm Drainage Report Section 4.5 — Please discuss whether the StormFilter is an
online or off-line system. The plans seem to indicate that this is an off-line system. If an off-line system is proposed, a flow splitter shall be required. Please include sizing calculations
for the proposed flow splitter. Calculations should include an estimate of the treatment flow to be directed to the StormFilter as well as the expected bypass flow.
10. Storm Drainage
Report Section 4.5 — Although it is not indicated in the report or the plans, it is assumed that the 27 inch cartridges are proposed based on the treatment rate assumed of 22.5 gpm per
cartridge. The DOE approval of this system limits the flow for these cartridges to 11.3 gpm per cartridge. Therefore the calculations provided for amount of cartridges are incorrect
and requires modification. As more cartridges will be required, the vault sizing will also require modification.
11.Storm Drainage Report Section 4.5—This section references Appendix
D for further calculations on treatment design but none are provided.
12. Storm Drainage Report Section 4.6 — The storm water report states that the 25-year storm was used to verify
the pipe conveyance calculations. However, the 25 year storm event has not quantified. The calculations provided in Appendix D only indicate the flowing full capacity of the pipe. They
do not indicate the expected 25 year flow to the pipe. Please include an estimation of the 25 year event for comparison and estimation of available capacity.
13. Storm Drainage Report
Appendix D — A stormwater program printout has been provided without any explanatory information. For instance, a 2 year flow is shown but the treatment flow is not indicated. A treatment
flow of 1.49 cfs is indicated in Section 4.5 but this calculation is not apparent in Appendix D. Please provide further information on what the report is demonstrating. This further
information should include how the model is sizing the facility as well as how the treatment flow was calculated based on the flows shown.
14. Storm Drainage Report Appendix D — Although
no explanation is provided, it appears that the stormwater design is based on matching post development to predevelopment flows. This is only appropriate for detention system design.
A retention system must be sized to handle all flows that discharge to it for up to the 100 year event. Therefore, the sizing computations are incorrect and require modification. For
infiltration systems, it is appropriate to model the 100 year flow and determine what stage is reached within the actual facility. Please note, freeboard must be provided.
15. Storm
Drainage Report Appendix D — Per Section 111-3.6.8 of the 1992 DOE Manual, the stormwater infiltration facility shall infiltrate the 10 year storm in 24 hours and the 100 year
storm in 48 hours. Please provide calculations demonstrating the required drawdown has been provided.
Conditions of Approval:
16. Condition No 1. — The MDNS requires the infiltrative
surface to have at least 6 feet of separation from high ground water or submit a report supporting no adverse impact to the adjacent properties. The design does not address this requirement.
17. Condition No. 8 — The estimated water usage was not supplied as part of the civil plan submittal.
18.Condition No. 13 — The refuse construction details and Lemay approval was not
part of the civil plan submittal.
19. Condition No. 15 — The landscaping plan does not appear to meet the requirements set forth in the project approval.
20. Condition No. 16 — The
irrigation plan does not appear to meet the requirements set forth in the project approval.
Construction Plans:
The following review was based on the sheets provided. A water plan
showing the proposed water system was not provided as part of this review. Therefore, comments related to water design were limited to the water information that has been provided. The
next plan submission will require the inclusion of a water plan. This plan should include the same type of information provided for the sewer system on sheet C19.
All Sheets:
21.Please
revise the approval block to read Development Services Engineer instead of Engineering Plan Examiner.
22. The plans as currently shown are not stakable. Stationing information needs
to be tied to something such as a benchmark.
Sheet 1 of 32:
23. Please add the Hearing Examiner’s Conditions of Approval to the cover sheet.
24. Please label the 100-year flood plan with elevation on all sheets that show this area.
25. Per
Condition of Approval #7, a 20 foot shoreline easement is required. Please show this easement on this sheet.
Sheet 2 of 32:
26.The City of Yelm (COY) requires the applicant to contact
Lemay Refuse Disposal for review of the dumpster site plans. Please have Lemay review and sign a site plan to be returned to the City in the next review.
27. The City requires the applicant
to contact Yelm Postmaster for approval of the mail box locations. Please have Yelm’s Postmaster review and sign a site plan to be returned to the City in the next review.
28.The site
plan shows 23’ drive aisles. Does this take into account the possibility of the typical garage overhang or the carports? If the carports extend beyond the actual parking stalls.
29.The
double ADA parking stalls require an eight foot striped area between them per ADA requirements and detail No 9 on Sheet C22. Please revise.
30. The project has two separate gates,
how is emergency access for fire and EMT vehicles going to be preserved?
31.The City’s Design Guidelines require the cross walk/pedestrian ways to be constructed of dissimilar materials
from the parking lot. Striping is insufficient to meet this requirement. An example of sufficient materials would be stamped concrete. Please revise. Sheet 3 of 32:
32. An inlet protection
detail and notes are provided but no inlet protection is shown on the plans. Is inlet protection to be provided? If so, please indicate the location. Sheets 5 and 6 of 32:
33.The
matchline on sheet 5 does not match that of 6. Therefore, there is not an overlap and information is missing, Please revise.
34.The storm water area between the buildings typically is not considered “clean” runoff. This area will experience fertilizer and landscaping pesticides that, as proposed, will be conveyed
directly to the infiltration area without treatment. This area should be routed to the treatment facility before disposal.
Sheets 7 thru 16 of 32:
35. COY Development guidelines
require a mm sewer main depth of 60”. Unless necessary for a conflict show sewer main at 60”. It is currently shown at depths up to 10’ deep.
36. COY Development guidelines require
a mm water main depth of 42”. Unless necessary for a utility conflict show water main at 42”. It is currently shown at depths up to 8 feet deep.
37. It is not appropriate to provide
the sewer, water, and storm profile information all on one sheet. This creates confusion and overall plan clutter. Further, there appears to be little information provided regarding
the water and sewer profiles including depth of pipe, size and length of main, etc. Please provide separate profile sheets for each utility and provide the required information per the
City plan checklist.
38.The water main appears to be in conflict with other utility crossings. Please show all utility and service crossings on the profile.
39.The 12” storm pipe
angle at catch basin #30 does not appear to be constructible with out removing more catch basin material than the knockout allows. Please change catch basin to a type 1-L.
40.The 12”
storm pipe angle at catch basin #47 does not appear to be constructible with out removing more catch basin material than the knockout allows. Please change catch basin to a type 1-L.
41. Catch basin #6 has a rim elevation to invert is greater than 5 feet. This should be changed to a type 2-48” catch basin.
42. Catch basins #10 and #39 have less than 2 feet of
cover over the storm pipe. Please specify what type of pipe you are proposing to use. With the limited cover shown, ductile iron pipe will likely be required.
43. Please show the restoration
of 106th Ave for the water main installation.
Sheet 17 of 32:
44. The proposed 10’ center turn lane’s width does not match the existing center turn lane width of 11’. This should be consistent through out the street length.
45.The
sidewalk appears to meander around utility conflicts. A meandering sidewalk is typically not allowed and the City usually requires these utilities to be relocated. Please consult with
Community Development Department for exact requirements.
Sheet 18 of 32:
46. It is recommended to install at least one valve on the Access Way E/D/F water main loop. This ioop can
not be maintained without shutting down the complete loop.
47. What is the purpose of the tee and plug at Sta. 52+68 (Access Way A)? Are you intending to extend this in the future?
48.A water easement is required for the lO6 water main connection. This will be a private property overland connection until the roadway is constructed.
49.A Reduced Pressure Backflow
Assembly (RPBA) is recommended to be installed on all three story buildings and all commercial buildings are required to have a RPBA.
50. Please call out actual water meter size, not
a range. (Typical all bldgs.)
51. Fire Department Connections need to be located a max of 15 feet from fire hydrants. See C28 note No. 9.
52.The DDCV location at the water main is
required to have a tee and a gate valve. (Typical all locations).
53.The project proposes to connect two buildings to one DDCV. This needs to be reviewed by the COY Fire Marshal before
approval may be granted.
Sheet 19 of 32:
54. The 2” Access Way B force main should extend to the Commercial Bldg #1 step tank and the service line connected at a perpendicular angle.
55.The Access Way B force main needs to
have a 2” end of line clean out installed. See COY standard detail 7-20.
56.The Access Way C/F tee should have the two valves located on the upstream pipe runs.
57.The access way
D/E tee should be removed. The access way F force main should be continuous to the 2” end of line clean out.
58. Access Way F force main should extend to Step Tank E2 where a 2” end
of line cleanout should be installed.
59. The sewer tee, gate valves and thrust blocking located at Station 44+41 should be removed.
60. All step tank service lines should be connected
as shown in COY standard detail 7-1. Please remove the gate valves shown on each service line.
61. Please show the locations of all sewer Carson Boxes. If these are located in the
driving surfaces these boxes must be H-20 load rated.
62. Please show all step controller locations, method of mounting the step controller, a hose bib within 50’ of the step tank
pumps, tank access points and H-20 load bearing lids. (Typical all step tanks)
63.All step tanks must be H-20 rated tanks.
64. Each step tank must have a separate power meter..
65.
Commercial Bldg 1 step tank exceeds the City of Yelm’s depth requirement of 6’ from finish grade to the tank invert. Please revise.
66. Commercial Bldg 1 service line should be connected
per COY detail 7-1.
67. Commercial Bldg 1 — The step tank sizing does not meet the sizing requirement of COY. Please see comment No 79.
68. Commercial Bldg 2 step tank exceeds the City of Yelm’s depth
requirement of 6’ from finish grade to the tank invert. Please revise
69. Commercial Bldg 2 — The step tank sizing does not meet the sizing requirement of COY. Please see comment No
79.
70. Step Tank A is located too close to the covered parking structures. This tank should be rotated or relocated to a different area.
71. Step Tank B is located too close to
the covered parking structure. This tank should be moved over or relocated to a different area.
72. Step Tank C is located too close to the covered parking structure. This tank should
be rotated or relocated to a different area.
73. Step Tank D is located too close to the garage foundation. If the City has to remove or replace this tank the foundation is only 2
feet away from the tank.
74. Step Tank F2 is located too close to the covered parking structure. This tank should be moved over or relocated to a different area.
75. Step Tank H
is located too close to the covered parking structures. This tank should be rotated or relocated to a different area.
76. Step Tank I is located too close to the covered parking structure.
This tank should be moved over or relocated to a different area.
77. Step Tank 3 is located too close to the covered parking structures. This tank should be rotated or relocated to
a different area.
78. Step tanks need to be a minimum of 10’ from water mains. Please verify the all step tanks meet this requirement.
79, As stated in the Step System Report,the
COY uses the COY Development Guidelines and the DOE orange book. The DOE orange book requires that all step systems be sized
with 24 hours of additional storage or install a generator switch and receptacle plug. This requirement has not been met. An example would be Bldg A step tank has been sized for 3185
gpd with a safety factor of 1.5 (residential). This equates to 4777 gpd. However there must be an additional 24 hours of storage or a generator plug in addition to the design volume.
(Typical of all step tanks in this design).
80. Please look at each tank to verify that the liquid level in the tank is actually the required amount. In this case it appears the design
has not taken into account the free board that in needed to install the pump system. The step pumps will hang down in to the tank and this area between the pump off level and the top
of the tank is not usable for storage.
81. Step tank E2 appears to be undersized. The step report states that this building and pool is expected to produce 750 gpd above the calculated
residential flows. However you have only provided an additional 230 gpd in the step tank.
82.The step sewer report states that the pool consultant will arrange for the disposal of
the pooi water. This should be discussed before the step tank is sized because it may affect the sizing of the tank.
83.The City does not typically allow dumpster pads to be connected
to the sanitary sewer without Public Works approval.
84.The plans do not show any provisions and/or design for grease interceptor on the commercial bldgs. This is a requirement for
any restaurant or grease producing facility. The grease interceptor is required to be installed outside the building.
Sheet 20 of 32:
85.The control structure detail should be drawn
to scale to illustrate what are the internal dimensions inside the structure for maintenance personal.
86.The proposed down turned elbow with a 2.75” orifice should be replaced with
a frop tee inlet. The downturned elbow can be blocked by a single piece of debris. The tee inlet will provide a secondary inlet to the water quality bypass.
Sheet 22 of 32:
87. Please remove the road monument detail and place the COY detail on the plans.
Sheet 23 of 32:
88. Please replace the end of line clean out with the current COY detail on the
plans.
Sheet 24 of 32:
89.The Stormtech general notes are incomplete. Please add note no. 3, 4 and 5.
Sheet 25 of 32:
90.The Stormtech notes are incomplete. Please add the remaining
notes.
Sheet 27 of 32:
91.The water main general notes should have 16 notes. The plans have 15 shown. Please update.
92. Please add the approved COY Fire Department Connection detail.
Sheet 28 of 32:
93. Please use all available City of Yelm Standard details with City boarders attached. The standard details may be obtained from the city website.
94. It appears
that this plan set will need the following City of Yelm sewer details: 7-1, 7-3, 7-4, 7-6, 7-7, 7-12, 7-14 or 7-15 depending on pump configurations, 7-16, 7-18, 7-19, 7-20 and 7-21.
Sheet 29 of 32:
95. Please show on the step tank details what the liquid level will be in each tank, access locations, center baffle wall and orifices in the baffle wall.
96. Add details for a load bearing ring and cover over the access points that are located in the driving aisle.
Sheet 30 of 32:
97. Please remove the Orenco standard details from
the plans. These details conflict with the COY Standard details.
Landscaping Plans:
98.The landscape planting plans appear to have some conflicts with proposed vegetation and proposed
utilities. Please review the proposed vegetation located in the vicinity of water mains, fire department connections, DDCV and fire hydrants.
99 The landscape plans show a fence, however
I was not able to find any callouts or construction notes for this. Please add details for the fence.
100. The Conditions of Approval require type II landscaping area on all sides
of the project except adjacent to the open space. Should the area between the south property line and Access Way A have Type II landscape shown?
101. Condition of Approval iSa requires
the landscaping to be drought tolerant shrubs and bark instead of grass.
102. The open space area between Bldg E and Yelm Creek was conditioned to be left in a natural open space.
The landscape and irrigation plans show this area to be lawn area with irrigation system.
Irrigation Plans:
103. The irrigation point of connection was not shown on the plans. Please
add a call out for the location of the meter, double check valve and irrigation line sizes.
104. Replace the irrigation double detector check valve detail with the current COY detail.
This may be downloaded from the City’s website.
105. Condition of Approval 16 requires the irrigation system to be drip irrigation. Please revise.
106. The irrigation plan shows a rotor irrigation system to be installed in the natural open space area. This is contrary to the conditions of approval.