HomeMy WebLinkAbout20063264.tiff Weld County Planning Department
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STATE OF COL 21r6 leo
^OFFICE OF THE STATE ENGINEER �;c c .1v?!.
Division of Water Resources
Department of Natural Resources
1313 Sherman Street,Room 818 ≤
Denver,Colorado 80203 r t876s %
Phone(303)866-3581 -
FAX(303)866-3589
Bill wwwater.state.co.us September 28, 2006 Governor
w. Owens
Russell George
Tom Morton Executive Director
Weld County Planning Department Hal D.Simpson,P.E.
State Engineer
4209 CR 24.5
Longmont, CO 80504
Re: St. Vrain Lakes Filing 1, PF-1078
Secs. 35 and 36, T3N, R68W, 6th P.M.
Water Division 1, Water District 5
Dear Mr. Morton:
We have reviewed the information submitted for the above referenced proposal
to subdivide a 230-acre parcel into 548 single-family residential lots and 230 acres of
open space and continued Oil and Gas Production Uses. According to the information
provided this subdivision is a portion of the St. Vrain Lakes proposal that we previously
commented on in letter dated October 31, 2005. The submitted information does not
appear to address the questions raised in the October 31, 2005 letter. Prior to further
evaluation of the water supply plan the applicant must address the questions that were
previously raised.
Should you have any questions, please contact Joanna Williams of this office.
Sincerely,
././e
Kevin G. Rein, P.E.
Chief of Water Supply
KGR/JMW
CC: Jim Hall, Division 1 Office
Water Supply Branch
Subdivision File
2006-3264
rcter"-•
e" Weld County Referral
ISeptember 21, 2006
C.
COLORADO
The Weld County Department of Planning Services has received the following item for review:
Applicant Tom Morton Case Number PF-1078- Filing One
Please Reply By October 20, 2006 Planner Kim Ogle
Project PUD Final Plan for 548 single family residential lots along with230 acres of opens
space and continuing Oil and Gas Production Uses (St. Vrain Lakes PUD)
Legal Part of Sections 35 and 36, T3N, R68W of the 6th P.M., Weld County, Colorado.
Location Multiple parcels generally located East of and adjacent to the 1-25 Frontage Road,
and north of the St.Vrain River. For a more complete description see Legal.
Parcel Number 1207-36-000056, 1207-36-000031; 1207-36-000025; 1207-35-000051;
1207-35-000049 and 1207-35-000039
The application is submitted to you for review and recommendation. Any comments or recommendation you
consider relevant to this request would be appreciated. Please reply by the above listed date so that we may
give full consideration to your recommendation. Any response not received before or on this date may be
deemed to be a positive response to the Department of Planning Services. If you have any further questions
regarding the application, please call the Planner associated with the request. Please note that new
information may be added to applications under review during the review process. If you desire to
examine or obtain this additional information, please call the Department of Planning Services.
Weld County Planning Commission Hearing (if applicable) December 6, 2006
❑ We have reviewed the request and find that it does/does not comply with our Comprehensive Plan
lit We have reviewed the request and find no conflicts with our interests.
❑ See attached letter.
Comments: \K"CS& tNC—W:1
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Signature Date OS- -ei.f
Agency 7.-e•sf\LAe C� YU
G
r. Weld County Planning Dept. + 4209 CR 24.5 Longmont,CO 80504 4 (720)652 4210 ext.8730 4- (720)652 4211 fax
0outryN MOUNTAIN VIEW FIRE PROTECTION DISTRICT
Administrative Office:
9119 County Line Road•Longmont, CO 80501
E1�. F (303)772-0710•FAX (303) 651-7702
het
October 6,2006
Mr.Kim Ogle
Weld County Planning Department
4209 Weld County Road 24.5
Longmont,CO 80504
Dear Mr.Ogle:
I have reviewed the submitted material pertaining to the final plat and change in zone for the Saint Vrain
Lakes, Filing I located south of Highway 66 and west of Weld County Road 13 (Case Number: PF-1078,
Case Name: Tom Morton). The Fire District approves of the final plat in accordance with the following
comments and stipulations:
• All fire hydrants must be approved and in service before building permits may be issued. The Fire
Districts requests that the most demanding fire hydrant be flow tested and the results of the flow test
forwarded to the Fire District.
• Fire apparatus access is satisfactory as shown on the plans submitted. All roads must be installed,
street intersections signed and be provided with at least one layer of asphalt before building permits
may be issued.
• All structures shall have a legible address that is clearly visible from the street fronting the property.
At the time construction begins temporary signs may be provided.
• As soon as the final plat is approved,please have the applicant provide to the Fire District an eight and
one half-inch by eleven-inch map of the subdivision showing the street configuration, street names,
hydrant locations and addresses if available.
We appreciate being involved in the planning process and should you have any questions, please contact
me at 303-772-0710.
Sincerely,
LuAnn Penfold
Fire Marshal
LMP/Ip
cc: project file
Ip10.08.06
Station 1 Station 2 Station 3 Station 4 Station 5 Station 8 Station 7
9119 Cnty Line Rd. 14308 Mead St.,Unit B P.O.Box 575 P.O.Box 11 10911 Dobbin Run 50 Bonanza Dr. P.O.Box 40
Longmont,CO Longmont,CO 299 Palmer Ave. 8500 Niwot Road Lafayette,CO Erie,CO 100 So.Forest St.
80501 80504 Mead,CO 80542 Niwot,CO 80544 80026 80516 Dacwro,CO 80514
Page 1 of 2
Esther Gesick
From: Kim Ogle
Sent: Tuesday, November 21, 2006 1:47 PM
To: Esther Gesick
Subject: FW: PF-1078 ... FW: Revised condensed Carma drainage comments
Importance: High
Attachments: PF-1078St. Vrain Lakes PUD Small Summry Drainage Comments.doc; Kim Ogle.vcf
Kim Ogle
Planning Manager
Southwest Weld Service Center
4209 CR 24.5
Longmont, CO 80505
720.652.4210 extension 8730 T
720.652.4211 Facsimile
kogle@co.weld.co.us
From: Peter Schei
Sent: Monday, November 20, 2006 3:31 PM
To: Kim Ogle
Cc: Tyler Packard; Katherine Strozinski
Subject: PF-1078 ... FW: Revised condensed Carma drainage comments
Importance: High
20-Nov-2006.
Good Afternoon, Kim:
Please find attached an Updated Memorandum from Public Works wrt drainage.
PW is willing to help with the preparation of the resolution as necessary ... as you wish.
Have a great day, Peter.
P.S. Formal copy to follow via post.
Pete/SCHEL P.E.,Ns.P.E.
Weld County-Public Works Department
1111 -H Street,Greeley,CO 80632
970.356.4000 x3750
pscheiaco.weld.co.us
"Welcome Home - to Weld County"
From: David Bauer
�. Sent: Monday, November 20, 2006 2:28 PM
To: Peter Schei
Cc: Brian Varrella
Subject: Revised condensed Carma drainage comments
11/21/2006
Page 2 of 2
Okay, second try.
Here's a 2.67 page summarized set of comments boiled down from the more lengthy and
specific mid-October comments on this project.
Thanks for your patience
Dave B
r-.
11/21/2006
tMEMORANDUM
' TO: Peter Schei,P.E., Public Works Department DATE: November 17, 2006
V� FROM: David Bauer, P.E.,Public Works Department
SUBJECT: PF-1078 St. Vrain Lakes Filing 1 Drainage Report Summary review
• comments
COLORADO
Weld County Public Works Department reviewed the Filing 1 Drainage Report submitted for the proposed St. Vrain
Lakes PUD (PF-1078) project in early October and submitted comments to the applicant on October 19, 2006. No
additional information has been submitted as of the date of this memo. Comments made during this phase of the plans
review process may not be all-inclusive, as other concerns or issues may arise following the applicant's response to
questions or issues that arise as a result of the requests herein.
Comments
Comments on the proposed St. Vrain Lakes PUD drainage design can be categorized based on general types of drainage
issues. Concerns that arose during the October review include management of offsite stormwater, grading, storm pipe
design, swale design, inlet design, erosion control and stability of the designs, and completeness of the report. A detailed
review identifying specific issues and concerns at specific locations in the proposed St. Vrain Lakes PUD site is provided
in the October 19, 2006 comments from Public Works. These specific comments are summarized below; please refer to
the October 19 memorandum for more detailed description and requests.
r^
_iffsite Flows
Stormwater runoff from areas to the north of the St. Vrain Lakes PUD Filing I produce in excess of 200 cubic feet per
second (cfs) during the 100-year storm event. Un-constructed or proposed offsite drainage management facilities cannot
be considered in design of the St. Vrain Lakes PUD project. the applicant is requested to size St. Vrain Lakes drainage
facilities to convey the un-detained offsite flows through or around the St. Vrain Lakes PUD site.
The report text Historic Condition discussion inappropriately mingles description of proposed and historic flowpath
scenarios that do not currently exist on the ground. This mixing of historic with proposed drainage routing incorrectly
determines the peak flows and is not acceptable.
Grading
The applicant submitted an overlot grading plan but not a final grading plan suitable for construction. Please provide a
Final Grading plan(Construction Drawings).
In some instances the proposed overlot grading would direct runoff from many lots to a single point on a proposed
residential lot; this raises significant concerns.
Storm Sewer Pipe Design
A significant area drains to Design Point 8 (proposed Weld County Road 9.5); please provide a road overtopping analysis
showing the inundated area and maximum flow depth in the road. Please show on the drawings and plans the 100-year
.area of inundation. A designed swale will be needed south of the roadway.
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Proposed flow velocities for some of the storm pipe segments exceed 15 feet per second. These velocities will be unstable
nd a hydraulic jump will occur within the pipes resulting in surging flow and reduced capacity. Please address the
roposed steep storm pipe sections with an analysis of flow stability. Please evaluate the actual capacity of these pipes
and provide calculations to ensure that street inlets are not surcharged.
The drainage report is incomplete without EGL and HGL lines shown on all storm sewer pipe profiles and for the
manholes. Please evaluate the plunging-flow energy and head losses and resultant backwater conditions where multiple
pipes converge in manholes. Please evaluate the potential that the proposed high HGLs may lift manhole lids. Please
provide an evaluation of the need for thrust block protection for storm sewer junctions and manholes at locations proposed
to have the high flow velocities and potentially pressurized flows.
Swale Design
The proposed designs show multiple locations where streets will overflow to private property. The path of the proposed
overflows must be managed in designed swales with erosion protection. These swales must be placed in dedicated
drainage easements.
Proposed channels show peak flows in excess of 35 cfs moving between proposed houses at some locations. Please
provide the peak flow velocity for these and all channels and provide details and stability calculations, and provide
appropriate erosion protection design calculations. Describe what public safety measures are planned for this high flow
channel between homes.
Street Inlet Design
The proposed designs show multiple locations where street inlets will overflow (by design) and allow flow to cross
„...xpadways. Please provide proposed water depths where these developed flows cross the roads.
There are few or no inlets proposed on the steeper streets (WCR 9-1/2, Eagle River Road, Yampa River Road, Fountain
Creek and Cimmaron River Road). Please address the high flow velocities and unstable flow regimes (hydraulic jumps)
on the proposed steep streets. Please provide detailed profiles and calculations showing how the rapid moving stormwater
leaves these streets in order to enter inlets on the east-west roads. Please provide an evaluation of the interaction of the
high velocity steep street flows with ponded water at the inlets on the east-west roads.
The drainage report states that all inlets and storm sewer pipes have been sized to accommodate the 100-year event.
However, the spreadsheets show that the proposed inlets collect less than 50 percent of the developed flows. Please
provide the correct capacity. Please describe the amounts and routing of the un-captured flows for all inlets.
The inlet evaluation sheets for many inlets at critical locations of the site are missing from the report. Please provide the
inlet evaluation sheets for these inlets.
Erosion Control
The drainage report contained no designs or calculations for erosion control Best Management Practices. Please provide
the total flow, slopes, peak flow velocity, calculations of the channel flow regime stabilities, and provide shear stress
evaluations of the proposed erosion protection designs for all proposed channels, swales, spillways, and storm pipe
entrance and discharge points. Please provide provide D50 calculations for proposed rip-rap and show the D50 values on
the construction drawings.
Due to the proximity of the St. Vrain River to the proposed grading on the eastern-most end of the project, Public Works
,,,,bequests that the Detention Pond 104 in Tract N(Sheet PD01)be built at the earliest phase of construction.
C:\WMMI\Temp\Temporary Internet Fila\OLKIES\PF.1078St Vram Lake PIM Small Summry Drainage CommrnuAoc
Page 2 of 3
Completeness
A table of Times of Concentration calculations for the proposed developed Filing I sub-basins was provided in an
Appendix, however, no tabulation of the Times of Concentration calculations for the historic onsite and offsite sub-basins
ias provided. The applicant is requested to provide this information that is essential for determination of 5-year historic
peak flows.
The reference to un-disturbed areas needs to be modified to recognize that preliminary grading, at the developers risk
prior to Final Plat approval, has occurred on a large portion of this site. Runoff from these onsite disturbed areas will be
increased until build-out and must be managed now, in the current designs, use of the pre-disturbance soil conditions is
not appropriate for these now disturbed areas.
Sizing of detention requirements must take into account the total runoff generated in a basin. Please see the UD&FCD
criteria manual and Weld County Addendum for guidance.
Other Comments
For completeness of Weld County files, please provide copies of all U.S. Army Corps of Engineer's 404 permits for
construction in wetlands at the St. Vrain Lakes PUD site.
The elevation differential across Detention Pond 104(tract N)embankment is greater than 20 feet. This embankment falls
under the jurisdiction of the State Engineer's Office as a dam. Please provide documentation of compliance with the
requirements of the State Engineer's Office.
All drainage facilities (detention ponds, channels, swales, inlet and outlet structures, etc.) must be placed in recorded
drainage easements shown on the Final Plat. Easements shall be shown on the final plat in accordance with County
standards (Sec.24-7-60)and/or Utility Board and service provider recommendations.
Ield County will not maintain drainage easements / stormwater detention ponds / landscaped swales / related areas.
Maintenance of all drainage facilities shall be the responsibility of the owner of the St. Vrain Lakes Metro District or
successor. Please add a note to the drawings and Final Plat so stating.
Recommendation
u The applicant is requested to re-submit a revised drainage report and drawings addressing the comments above.• 4
C:\WINNTTemp\Temporary Interne Filee\OLKIES\PF-l07SSt Vram Lakes Pun Small Summry Drainage Commmb.doc Page 3 of 3
MEMORANDUM
11 I I II�. TO: Pe Bauer Public Works Department DATE: October 13,2006
FROM:t David Bauer,P.E.,Public Depa tmenrtment
Q SUBJECT: PF-1078 St.Vrain Lakes Filing 1 Drainage Report review comments
COLORADO
Weld County Public Works Department has reviewed the Filing 1 Drainage Report submitted for the proposed St.
Vrain Lakes PUD (PF-1078) project. Comments made during this phase of the plans review process may not be
all-inclusive, as other concerns or issues may arise following the applicant's response to questions or issues that arise as a
result of the requests herein.
Comments
General Comments:
1. The St. Vrain Lakes PUD Filing 1 "Phase III" Drainage Report is incomplete, contains significant errors and
conflicting information. The report is unacceptable as presented. See the detail comments below.
2. Carroll & Lange submitted a St. Vrain Lakes PUD Filing 1 "Phase III" Drainage Report dated June 6, 2006,
revised August 7, 2006, and stamped and signed August 14, 2006 by Katherine Strozinski, P.E. #37307. Also
signing the report was Monica Unger, E.I.T. whose name appears on most of the calculation sheets in the report.
The Filing 1 "Phase III" Drainage Report contained 16 pages of text and over a hundred pages of supporting
calculation sheets,spreadsheets, and computer output. This report was received at Weld County Public Works on
August 23,2006.
3. St. Vrain Lakes Filing 1 encompasses approximately 469 acres of the larger 1320 acre St. Vrain Lakes project.
Filing 1 is planned for 546 single family and 6 multi-family home sites,roads,lakes,and open space.
4. The St. Vrain Lakes PUD Filing 1 "Phase III" Drainage Report needs to be stand-alone and include information
on offsite flows that impact the St. Vrain Lakes PUD Filing 1 site. Please provide the calculations for historic
flows for all offsite basins in the report. See the detail comments below.
5. The Time of Concentration tabulation in Appendix B contains values for 68 proposed sub-basins. For over 60 of
these calculations, proposed slopes are listed as 2.0 percent. A brief look at the proposed grading plans and
Drawings DRI through DRS reveals that most sub-basins have proposed slopes not equal to 2.0 percent but range
from 0.8% to over 4%. The slope labels on the Drawings do not match the Appendix table. All of the Times of
Concentration for proposed basins are potentially erroneous and will need to be re-calculated. The result is that
the computed runoff values are also erroneous. Inlet, pipe and detention pond sizings will all need to be re-
calculated.
6. Basin Dl of the St. Vrain Lakes PUD Master Drainage Report and Stormwater Management Guide, is the
equivalent of Basins OS1 and OS2 of the St. Vrain Lakes PUD Filing 1 Drainage Report. This offsite —130 to
144 acre area will produce approximately 200 cfs of runoff during the 100-year storm. This offsite flow must be
managed through the St.Vrain Lakes PUD Filing 1 area. See the detail comments below.
7. The steep proposed slopes present a drainage management challenge. Proposed street inlet and pipe designs need
to address inlet clogging,by-pass, and the unstable flow regimes in the streets and in the storm sewer pipes. The
proposed designs are incomplete,inadequate, and not acceptable. See the detail comments below.
8. The St. Vrain Lakes PUD Filing 1 "Phase III" Drainage Report is incomplete without EGL and HGL lines shown
on all storm sewer pipe profiles.
9. Design flow information is missing for critical points of the proposed storm drainage system. The report is
incomplete without that information. The safe function of these critical areas is incomplete until these items are
addressed. See the detail comments below.
M\PIANNING-DEVaOPMFNT REVIENN-Final Pig(PP,MF.MIF)'PF-101854.Vrain Lakes PUDWF-1078St Vram Lakes PUD-Filing l-Drainage Cummmndoc Page 1 of 6
10. The flow directions depicted by arrows on the drawings are wrong; the convention is that flow is perpendicular to
the contours. In some instances the proposed grading would direct runoff from over many lots to a single point on
a proposed residential lot; this raises significant concerns and is an unacceptable design and cannot be approved.
See the detail comments below.
11. The report and proposed design shows multiple locations where street inlets will overflow(by design) and allow
flow to cross roadways. Additional evaluation of these overflows is needed. The path of the proposed overflows
must be managed in designed swales with erosion protection, and the swales placed in dedicated drainage
easements.
12. Incorrect, mis-labeled, incomplete and omitted items noted in the red-lined preliminary drainage report will need
to be addressed and resolved.
13. The text of the St. Vrain Lakes PUD Filing 1 "Phase III" Drainage Report dated June 6, 2006 makes repeated
reference to the "approved" St. Vrain Lakes PUD Master Drainage Report and Stormwater Management Guide.
That report has not been approved; issues identified in Change of Zone comments provided to Carroll and Lange
remain un-addressed and un-resolved.
14. The drainage report contained no designs or calculations for erosion control Best Management Practices. Please
provide erosion and sediment control calculations for all swales,pipe outlets,and detention pond spillways.
Specific Drainage Comments:
1. The submitted St. Vrain Lakes PUD Filing I "Phase III" Drainage Report was incomplete and did not contain a
complete set of drawings to support the report, additional review comments may result when a complete report is
re-submitted. The report text does not reference the drawings provided with the Preliminary Drainage report
(C6.0, C6.1, C6.2 and C6.3). Those 4 drawings show match points for drawings (C7.0, C7.1, C7.2 and C76.3)
that were not provided. Please provide the appropriate drawings and tie those to the discussion in the text.
2. Please see the red-lined St. Vrain Lakes PUD Filing 1 Drainage Report for detailed comments.
3. Please address inconsistances between the St. Vrain Lakes PUD Filing 1 Drainage Report and St. Vrain Lakes
PUD Master Drainage Report and Stormwater Management Guide as noted in the comments and red-lined report.
4. The Filing 1 Drainage Report text repeatedly refers to Filing 1 and Phase 1 but the report contained no displays to
clarify the boundaries of those respective areas. The Filing 1 report should be stand alone, the applicant is
requested to provide a basic index map showing these areas.
5. Clarity of the report would be substantially improved by:
a. A simple tabulation of the 100-year peak flows for all offsite areas flowing to the St. Vrain Lakes site.
b. A simple tabulation for the 5-year historic peak flow for each of the onsite basins (historic, undeveloped
condition).
r. A simple tabulation for the 100-year developed peak flows for each of the onsite basins (proposed developed
condition).
6. The text discussion (page 3) of the existing condition (historical condition) is confusing. The text refers to
proposed Design Points not shown on the provided plans. The text discussion is confusing in that it combines
historic discharges with developed case discharges. Please revise the text to clarify what are historical offsite
flows,what are historical onsite flows, and then what are developed condition/proposed onsite flows.
7. The report text Historic Condition discussion inappropriately mingles description of proposed and historic
flowpath scenarios that do not currently exist on the ground. The text discussion (page 3 of the Filing 1 "Phase
III" Drainage Report) describes historic basins Dl and D2 flowing to Basin E because that is the intent of the
proposed final design. However, Basins Dl and D2 do not flow to an outfall in Basin E historically. This mixed
historic-proposed routing approach incorrectly determines the peak flows and is not acceptable.
8. The report text discussion of the historic drainage in Basin E states that the "existing lake area was assumed to
have a historic impervious value that did not reflect the currently existing water because the lakes did not exist
prior to mining operations". This is not an acceptable approach. The ponds exist. For the intent of design and
determination of peak discharges, the existing pond water surface areas are 100 percent impervious; rainfall on
the ponds will increase the water levels in the lakes. For the proposed condition, the new, re-graded pond water
surface areas would be used and would also be 100 percent impervious. Sizing of detention requirements must
take into account the total runoff generated in a basin. Please see the UD&FCD criteria manual and Weld County
Addendum for guidance.
M:(PLANNING-DEVELOPMENT REVIEWU-Final Plat(PF,MF,MJF)\PF-1078 Si Vrain Lakes PUDWF-IWBSt Vrain Lakes PUD-Filing(-Drainage Comments doc Page 2 of 6
9. A table of Times of Concentration calculations for the proposed developed Filing I sub-basins was provided in an
Appendix, however, no tabulation of the Times of Concentration calculations for the historic onsite and offsite
sub-basins was provided. The applicant is requested to provide this information that is essential for determination
of 5-year historic peak flows. The report is incomplete without this information.
10. The flow directions depicted by arrows on Drawings GRl through GR12 are wrong;the convention is that flow is
perpendicular to the contours. In some instances the proposed grading would direct runoff from over many lots to
a single point on a proposed residential lot; this raises significant concerns and is an unacceptable design and
cannot be approved.
11. Because of the potential that the runoff values will all be changed due to the errors in computing Times of
Concentration, no evaluations were made of the street inlet capacities and clogging factors for this review.
Following submission of a revised Filing I Drainage Report, the inlet capacities and other hydraulics will be
reviewed. It is likely that that review will result in additional requests and comments.
12. Please provide elevation labels for the proposed contours on all the plans and drawings. Legibility would be
improved by lightly shading the existing contours.
13. Please explain what the "Phase III" signifies in the title and text of the St. Vrain Lakes PUD Filing 1 "Phase III"
Drainage Report.
14. An overall site plan index showing all proposed Phase I construction on one sheet included in the St. Vrain Lakes
PUD Filing 1 "Phase III"Drainage Report is requested.
15. The text states that the overall site is 45.5 acres but that site improvements will occur on 17.27 acres, and that
Phase I will disturb 11.85 acres. Which is correct?
16. The drawings included in the St. Vrain Lakes PUD Filing 1 "Phase III" Drainage Report refer to Phase I and
Phase II drainage activities and features, however it is not clear from the text discussion what and where these
different Phase areas and constructed facilities are to be located. Please clarify these issues.
17. The drawings in the report show only a portion of the overall site and property boundaries, please show the
complete site.
18. The reference to un-disturbed areas needs to be modified to recognize that preliminary grading, at the developers
risk prior to Final Plat approval, has occurred on a large portion of this site. Runoff from these disturbed areas
will be increased until build-out and must be managed now in the Phase I designs.
19. The Construction Drawing plan set (dated 8/14/06, received 9/26/06) include a sheet (PP1) showing 6 Phases to
what in the drainage report encompasses Phase I. Please provide explanations (a table?) of the timing and
location of the different construction elements for each Phase. Please provide a drawing showing the entire site
and the location of each Phase. Please provide a drawing or figure showing the locations of all stormwater
discharges and all of the property lines.
20. The Overlot grading plan drawings show areas described as Phase 1,Phase 2,Phase 3 but no explanation of what
these Phases signify was provided. For example: Sheet GR4 shows Phase 1 and Phase 2 areas and Sheet GR6
shows a Phase 4. Please clarify with an explanation and show the different Phases on separate sheets. An
approximate schedule for the Phases of work would be helpful.
21. The text discussion of Basins C7, C8, C12, and C13 is unclear. Page 14 of the St. Vrain Lakes PUD Filing 1
"Phase III" Drainage Report states that these basins will be developed as multi-family and municipal lots however
the discussion goes on to state that the storm sewers have been sized for the undeveloped condition. Given the
large amount of offsite flows to move through this area, it appears that the allowable street capacities will be
exceeded. The path of the proposed overflows must be managed in designed swales with erosion protection, and
the swales placed in dedicated drainage easements.
22. Basin Dl of the St. Vrain Lakes PUD Master Drainage Report and Stormwater Management Guide, is the
equivalent of Basins OS1 and OS2 of the St. Vrain Lakes PUD Filing 1 Drainage Report. This offsite —130 to
144 acre area will produce approximately 200 cfs of runoff during the 100-year storm. This offsite flow must be
managed through the St. Vrain Lakes PUD Filing 1 area.
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•
23. It appears from the runoff and inlet capacity calculations for Design Point C8 that the 100-year storm would drain
37.5 acres of disturbed but undeveloped onsite ground (proposed basins C13, C12, C8, and C11) and to which
would be added the 200 cfs 100-year undetained discharges from Offsite basins OS 1 and OS2 (combined area of
144 acres), 181 acres total. The St. Vrain Lakes PUD Filing 1 "Phase III" Drainage Report runoff calculation
sheet(page 6 of 7) for Design Point C8 shows 48.8 cfs as the 100-year onsite discharge for the 37 acres. There
must be an error in the calculations; 37 acres times .67 C coefficient times 6.4 inches per hour yields a peak flow
of 160 cfs. The approximately 200 cfs from offsite basins OS1 and OS2 also flow to this Design Point and must
be included in the analyses.
24. The applicant has proposed a 10-foot type R street inlet on Bayshore Drive at Design Point C8 that captures a
proposed 25 cfs. Please provide additional analyses justifying this inlet capture rate selection and showing the
converging flow hydraulics of the manhole joining the stormwater pipes from Design Points C8, C11, and C13.
25. Considering that 360 cfs converge at Design Point 8, please provide a road overtopping analysis for Bayshore
Drive showing the inundated area around Design Point 8 and maximum flow depth in the road (an HGL for the
inlet and adjoining pipes is requested, HEC 22 has a suitable analytical tool). Please show on the drawings and
plans the 100-year area of inundation.
26. The first sentence of Section C, Hydraulic Criteria (page 5) of the St. Vrain Lakes PUD Filing 1 "Phase III"
Drainage Report states that all inlets and storm sewer pipes have been sized to accommodate the 100-year event.
However, the spreadsheets show that the proposed inlets collect less than 50 percent of the developed flows. For
example, at Design Point C8, the runoff calculation sheet (page 6 of 7) shows 48.8 cfs as the 100-year onsite
discharge while the proposed 10-foot inlet collects 25 cfs. In actuality over 300 cfs flow to this point. Please
correct these discrepancies.
27. Multiple proposed design points have pipe flow converging in manholes; please evaluate the plunging-flow
energy and head losses and resultant backwater conditions. The St. Vrain Lakes PUD Filing 1 "Phase III"
Drainage Report is incomplete without EGL and HGL lines shown on all storm sewer pipe profiles and for the
manholes. Please evaluate the potential that the proposed high HGLs may lift manhole lids.
28. Please address the proposed steep storm pipe sections with an analysis of flow stability.
29. Cross-section I-I on drawing DRS shows a swale between Design Point C8 and Design Point C14 that is sized to
convey the 100-year peak flow of 257.6 cfs. The trapezoidal channel evaluation for channel/swale I-I in the
Appendix C shows 254 cfs. Please correct these discrepancies. Please provide the peak flow velocity and
maximum shear stress evaluation for this and all channels and provide details and calculations showing the
stability of this channel and erosion protection design.
30. Also please describe how the 257.6 cfs or more of surface flow at Design Points C8 and C14 are to cross
proposed WCR 9.5, the major arterial road through the St. Vrain Lakes Filing 1 site. A designed swale will be
needed south of the roadway.
31. The February 2006 Master Drainage Report and Stormwater Management Guide describes 199 cfs flowing
undetained to the St. Vrain Lakes site from the 129 acres of offsite Basin D1. The St. Vrain Lakes PUD Filing 1
"Phase III" Drainage Report text discusses and some of the drainage plan drawings depict portions of a "St.
Acacius" subdivision which lies to the north of the St. Vrain Lakes site. Un-constructed or proposed offsite
drainage management facilities cannot be considered in design of the St. Vrain Lakes project; treat the offsite
areas as undeveloped land. In the absence of completely constructed and functioning upstream drainage
management facilities, the applicant is requested to size St. Vrain Lakes drainage facilities to convey the 199 cfs
of un-detained offsite flows from Basin Dl.
32. The St. Vrain Lakes PUD Filing 1 "Phase III" Drainage Report describes offsite runoff from the Richie Brother's
site located to the north of the St. Vrain Lakes project. To be considered in sizing of drainage facilities in St.
Vrain Lakes Filing 1, please provide Weld County stamped and signed copies of the designs, calculations,
discharge points, and as-built drawings of any completely constructed and functioning Richie Brother's
subdivision stormwater management facilities. Un-constructed or proposed offsite drainage management
facilities cannot be considered in design of the St. Vrain Lakes project; treat the offsite areas as undeveloped land.
In the absence of completely constructed and functioning upstream drainage management facilities, size St. Vrain
Lakes drainage facilities to convey the un-detained offsite flows.
M'.\PLANNING-DEVELOPMENT REVIEW)-Final Mat(PF,Mr.NUF)IPF-1078 Si.Vran Lakes PUDIPF-1078St Wain Lakes PUD-Filingl-Drainage Comments.doc Page 4 of 6
33. If the St. Vrain Lakes subdivision wishes to include completely constructed and functioning offsite subdivision
drainage management facilities,please provide Weld County copies of the designs,calculations,discharge points,
and as-built surveyed drawings stamped and signed by a Professional Engineer. Show all the offsite pond
discharge points on the plans with as-builts of the constructed conveyances (channels or swales) and installed
permanent erosion protection.
34. In the Appendix C table containing the pipe report for the 100-year event, the pipe node designations do not
match the Design Point names shown on the plans and profiles. The pipe lengths and design slopes shown in that
table do not match the drawings and profiles. Please correct these discrepancies.
35. The Appendix C table containing the pipe report shows flow velocities for some of the pipe segments in excess of
15 feet per second. Flow at these velocities will be unstable and a hydraulic jump will occur within the pipes
resulting in surging flow and reduced capacity to convey the predicted amount of stormwater. Note that some
pipes discharging into the lakes will have submerged outlets assuming the "operating" water surface elevations
shown on drawings DR1 through DR5 are correct. Please see Federal Highway Administration's "Hydraulic
Design of Highway Culverts"(HDS-5)or equivalent for evaluation techniques.
36. Please provide an evaluation of the need for thrust block protection for storm sewer junctions and manholes at
locations proposed to have these high flow velocities and potentially pressurized flows.
37. The inlet evaluation sheets for Inlets C11, C12, and C13 are missing from the report. These inlets are critical
protection to WCR 9.5. The report is incomplete without this information. Additional comments may be
forthcoming following review of these critical point inlets.
38. The triangular channel evaluation for channel D-D in Appendix C shows the 100-year peak flow of 35 cfs moving
between proposed houses. Please provide the peak flow velocity for this and all channels and provide details and
calculations showing the stability of this channel and shear stress evaluation of the proposed erosion protection
design of this and all other proposed channels.
39. The triangular channel cross-section for channel E-E is missing on Drawing DR4, please add this figure. The
channel evaluation for channel E-E in Appendix C shows the 100-year peak flow of 70 cfs moving between
proposed houses. Please provide the peak flow velocity for this and all channels and provide details and
calculations showing the stability of this channel and appropriate erosion protection design for flows of this
_ magnitude. Describe what public safety measures are planned for this high flow channel between homes.
40. Additional stormwater flow path information is required at the base of the hill where Yampa River Road has a
quasi-`Tee' intersection with Bayshore Drive and Willow Creek Run. The proposed design shows no street inlets
for the north-south segment of Yampa River Road. It appears that all of Basin A18 and Basin B15 flow to that
intersection. Please describe how these developed flows will cross the roads and pass to Pond 105.
41. According to the Appendix C table containing the pipe report, the 42 inch pipe at Point P-54 receives 260.39 cfs,
but at full capacity can convey only 112 cfs. Please describe the routing of the un-captured flows.
42. The inlet evaluation sheets for Inlets A6.1, A6.2,A7.2, A15.2, A-17, and A21 are missing from the report. Please
provide the inlet evaluation sheets for Inlets A6.1, A6.2, A7.2, A15.2, A-17, and A21. The report is incomplete
without this information. Additional comments may be forthcoming following review of these critical point
inlets.
43. It appears that Inlets A9 and A10 may capture 29.2 cfs each. The total developed case 100-year runoff at those
Design Points is 58.4 cfs. Drawing DR3 shows a swale between houses sized to convey 58.4 cfs. Please explain.
44. The proposed grading in Basins A5, A7, A8, and A10 indicate flow will be generally west to east, however the
flow arrows on Drawing DR3 shows the flows parallel to the proposed grading. In some instances the proposed
grading would direct runoff from over 10 lots to a single point on a proposed single residential lot (in a sump).
This approach to grading is unacceptable. Please correct the grading to protect each proposed lot from the runoff
from other locations.
45. The proposed grading in Basins A6, A9,A13, and A24 indicate flow will be generally north to south,however the
flow arrows on Drawing DR3 shows the flows parallel to the proposed grading. In some instances the proposed
grading would direct runoff from over many lots to a single point. This approach to grading is unacceptable.
Please correct the grading to protect each proposed lot from the runoff from other locations.
46. The proposed grading in other Basins (B1, B2, B5, B6, Al, A2, A15, A14, A17, A21) and others are also
erroneously labeled and would direct runoff in an unacceptable manner. Please correct the plans and drawings.
M:\PIANNING-DEVELOPMENT REVIEWU-Final Plat(PF,Off,MJF)\PF-1078 St.Wain Lakes POD'PF-1078St Vrain Lakes POD-Filing,-Drainage Comments doc Page 5 of 6
47. At the bottom of the hill south of Eagle River Road, Drawing DR3 shows a swale oriented east— west (Channel
A-A) in Sub-basin Al2. The detail section shows this swale (A-A) to be designed with an 8-foot bottom width
and capacity for 167 cfs. The plans show this swale oriented East-West, however downhill is approximately
South;please correct this discrepancy. Please describe in the text the routing of flows to and through this swale.
48. For completeness of Weld County files, please provide copies of all U.S. Army Corps of Engineer's 404 permits
for construction in wetlands at the St. Vrain Lakes PUD site.
49. The elevation differential across Detention Pond 104 (tract N) embankment is greater than 20 feet. This
embankment falls under the jurisdiction of the State Engineer's Office as a dam. Please provide documentation of
compliance with the requirements of the State Engineer's Office.
50. All drainage facilities (detention ponds, channels, swales, inlet and outlet structures, etc.) must be placed in
recorded drainage easements shown on the Final Plat. Easements shall be shown on the final plat in accordance
with County standards(Sec.24-7-60)and/or Utility Board and service provider recommendations.
51. Weld County will not maintain drainage easements / stormwater detention ponds / landscaped swales / related
areas. Maintenance of all drainage facilities shall be the responsibility of the owner of the St. Vrain Lakes Metro
District or successor. Please add a note to the drawings and Final Plat so stating.
Erosion and Sediment Control:
1. Due to the proximity of the St. Vrain River to the proposed grading on the eastern-most end of the project, Public
Works requests that the Detention Pond 104 in Tract N (Sheet PD01)be built at the earliest phase of construction.
Erosion Control drawings (EC1 through EC8) were only provided with one of the review plan sets. Please
include all of the erosion control drawings in each plan set.
2. These Erosion Control drawings (ED through EC8) show areas described as Phase 1, Phase 2, Phase 3 but the
legend shows proposed Phase 1 or Phase 2 BMPs. No explanation was provided regarding these sheets and the
confusing Phase I, 2, or 3 designations and activities. For example: Sheet EC3 shows Phase 1 or Phase 2 BMPs
in the legend,but the drawing is labeled Phase 3. Please clarify and show the different Phases on the separate EC
sheets. An erosion control narrative was found on Sheet DT2. To facilitate site inspections and onsite
discussions with the applicant's representatives, this narrative should be placed on the EC sheets in addition to
appearing on the detail sheet where it was found.
3. The riprap rundown for the Pond 104 emergency spillway is shown as narrowing at the base towards the junction
with the St. Vrain River. Please explain why the riprap apron is narrower at the base than at the crest. Please
provide erosional stability calculations and D50 sizings for this riprap that address the spillway overflow and also
the velocities in the river. Additional riprap toe-down will be required.
4. No riprap or other erosion protection designs or calculations were provided for pipe inlets and outlets. Please
provide calculations addressing total flow,slopes, and provide D50 calculations.
Recommendation
❑ The applicant is requested to re-submit a revised drainage report and drawings addressing the comments above.
The applicant shall address the comments listed above at the specific step of the review process stated. The review
process will continue only when all appropriate elements have been submitted. Any issues of concern must be
resolved with the Public Works Department prior to recording the Final Plat.
r.. •
M.\PLANNING-DEVELOPMENT REVIEWU-Final Plat(PP,ME.MJF)\PF-1O78 St Vrain Lakes PUD'PF-1078S1 Vrain Lakes PUD-Filmgl-Drainage Comments doc Page 6 of 6
tt 0 Weld (Maid,/ Planpinu Department.
Fy it ' t
MEMORANDUM
II cEtD
ei,
TO: Kim Ogle, Planning Department Manage °1 , t�-0lct� 006
P (
COLORADO ✓
SUBJECT: PF-1078 St. Vrain Lakes PUD-Filing 1 (Final Plan)2
Weld County Public Works Department staff, under the direction of County Administration, has reviewed this Final
Plan request. Staff comments made during this phase of the subdivision process may not be all-inclusive, as other
concerns or issues may arise during the remaining application process.
Comments
❑ The County remains under sustained development pressure and the associated burdens.
❑ Department staff offers comments of the proposed St. Vrain Lakes PUD — Filing 1. Comments are presented to
provide general guidance to the applicant.
❑ The proposed development shall comply with:
o The Mixed Use Development(MUD)area of Weld County and said criteria.
o The Manual on Uniform Traffic Control Devices (MUTCD),most recent version.
o The Americans with Disabilities Act Accessibility Guidelines(ADAAG), most recent revision.
J St. Vrain Lakes PUD —Filing 1 (six phases) is planned for up to 542 single-family residential homes, 2 multi-family
building sites(409 townhomes), a recreation facility, a school,a municipal center, and a utility outlot.
o The Construction Plans for St. Vrain Lakes — Filing 1 must include a sheet clarifying the phases (six) of
the proposed development. This sheet should be located towards the front of the plan set to help orientate
the plan readers. The sheet detailing the phases should be simple and uncluttered.
General Topics:
a The change of zone application for St. Vrain Lakes PUD did not anticipate the re-alignment of CR 9.5 (between CR
28 and SH 66), since the State of Colorado did not have an agreement in place.
❑ The applicant shall revisit their development proposal with the recent approval of the re-alignment of CR 9.5 project
by CDOT. The realization of this project was in-question previous to the applicant's submittal for final plat.
Construction of CR 9.5 (between the St. Vrain River and SH 66) is now planned for completion in September 2007.
a The current application does not address the change that has occurred and must further discuss& determine what will
be accomplished with CDOT funding and accompanying County goals (particularly the CR 9.5 re-alignment project).
These coordination efforts will better provide the County and the applicant an understanding of improvements,
timing,phasing, and responsibilities to efficiently move ahead.
❑ The applicant shall resubmit the traffic impact analysis, proposed phasing of the development and associated
improvements (on-site & off-site), construction plans, and improvements agreements (on-site & off-site).
Construction sequencing shall be addressed in detail; especially for off-site improvements.
--------- Page 1 of 5
Improvements Agreement(s) for Off-Site Infrastructure:
❑ The applicant has not submitted Improvements Agreements According to Policy Regarding Collateral for (off-site)
Improvements. It is critical to obtain an agreement with the applicant for impacts to County infrastructure by the
proposed development.
o The applicant shall be responsible for improvements attributed to the proposed development.• Typically,
an applicant is asked to construct one-half (1/2) the full-build out classified roadway cross-section
adjacent to the parcel being developed within the MUD area of the County. Should an applicant propose
development on both sides of a County roadway within the MUD, then the applicant is asked to construct
the complete (whole) classified roadway cross-section anticipated at full-build out.
o Any off-site improvements (attributed to the proposed development) accomplished with State and/or
Federal funding shall be accounted and said value(s)be collateralized being applied to vicinity location(s)
requiring improvements that are determined to be attributed to future phasing of the proposed
development. Of particular interest is the CR 9.5 project planned adjacent to St. Vrain Lakes PUD to be
funded by CDOT.
• The applicant is asked to address this topic with the Public Works Department to complete an
understanding of the responsible impacts and associated assessments.
o An agreement(s) shall be submitted to Public Works prior to scheduling a Board of County Commissioner
Hearing or recording of a final plat.
Improvements Agreement(s) for On-Site Infrastructure:
❑ The applicant has submitted Improvements Agreements According to Policy Regarding Collateral for (on-site)
Improvements. This agreement appears generally acceptable,but shall be revised and resubmitted to Public Works.
o Engineering and Supervision Costs were estimated to be 2.5% of the Improvements, which is too low.
The applicant should consider 5% (minimum) of the improvements costs.
o The Total Estimated Cost of Improvements and Supervision was estimated to be $3,490,366.19. The
applicant will be required to bond an additional 15% of the Total Costs for a One-Year Improvements
Warranty.
o An updated agreement shall be approved by the Board of County Commissioners (BOCC) prior to
recording any final plat(Phase 1).
Metro District/ Special District:
❑ Weld County will not maintain roadways, right-of-way median areas, drainage, streets, asphalt surfaces, concrete
improvements(curb, gutter,and sidewalk) or open space areas.
o These items shall be addressed within the metro district(operation &maintenance) documents along with
appropriate fiscal accounting.
Geotechnical/Pavement:
❑ The applicant has provided a pavement design in the Preliminary Geotechnical Engineering Report — Proposed
Mixed-Use Development, Carma Weld County Site, Weld County Road 30 (Highway 66) and Interstate 25 - Weld
County, Colorado,dated May 26, 2004,by Terracon(Terracon Project No. 25045122).
o Soil borings and analyses were not prepared for the future road alignments.
o The applicant shall prepare a final geotechnical / pavement design report prepared by a professional
engineer submitted with the final plan materials for each development phase. This report may be prepared
after overlot grading and utility installation has been completed.
• The report must evaluate subgrade soils associated with construction of the roadways.
• Final recommendations for pavement and base course thicknesses shall be included in the report.
❑ The applicant (engineer) must provide a `Typical "T" Style Grading' detail on Sheets GR6, GR7, GRl1, & GR12,
since it is missing.
Page 2 of 5
External Roadways:
❑ Felsburg Holt & Ullevig (FHU), the County's retained transportation consulting engineer, has provided comments on
the Traffic Impact Analysis—St. Vrain Lakes, Filing I - Weld County, Colorado, dated August 14, 2006, sealed by
Benjamin T. Waldman, P.E. with LSC Transportation Consultants, Inc., (project number: LSC #061160). Please see
the attached memorandum of comments from Mr. Chris Fasching,P.E. with FHU.
❑ At full-build-out how many vehicles per day will be using each cul-de-sac?
o The applicant (engineer) has chosen a roundabout (urban single-lane) design element with a hypothetical
daily service volume of 20,000 vehicles per day.
❑ SH 66 has been annexed by the Town of Mead in the vicinity of this development proposal. SH 66 is paved and
maintained by CDOT. The applicant shall coordinate with Mead and / or CDOT concerning respective roadway
improvements meeting MUD criterion.
o The applicant shall provide written documentation of this coordination to Public Works prior to
scheduling a public hearing.
❑ CR 13 is classified by the County (Weld County Roadway Classification Plan, June 2002) as a major corridor -
arterial road (to the east of Filing 1) and requires a 140-foot right-of-way. CR 13 is paved and under the jurisdiction
of Weld County adjacent to this proposal. The applicant shall coordinate with the County concerning respective
roadway improvements meeting MUD criterion.
❑ CR 11 has been annexed by the Town of Mead (to the north of Filing 1). CR 11 is gravel and maintained by Mead.
The applicant shall coordinate with Mead concerning respective roadway improvements meeting MUD criterion.
o The applicant shall provide written documentation of this coordination to Public Works prior to
scheduling a public hearing.
County Road 9 '/: Construction Plans (St. Vrain River to CR 28):
❑ General Note (Sheet GN1) #15 must be revised to a state fifteen (15%) percent maintenance bond shall be required.
This is a typographical error.
❑ The engineer must address minimum centerline arc lengths use in the roadway design. Some centerline arc lengths
appear too short for an arterial roadway design.
❑ The engineer must address minimum K-values used for vertical curves (crest& sag). Some K-values are smaller than
anticipated for an arterial roadway.
❑ Several of the Cross Sections shown on Sheets CS1 thru CS12 do not call out the road surface slope. The engineer
shall address these omissions with any corrections resubmitted to Public Works.
❑ Sheet DT2 shall show more clearly details of ADA-compliant Ramps incorporating detectable warning surfaces
(ADAAG)2.
• 2 ADA Standards for Accessible Design, U.S. Department of Justice—Nondiscrimination on the Basis of Disability by
Public Accommodations and in Commercial Facilities,28 CFR—Part 36,Revised July 1, 1994.
❑ CR 9 '/3 is classified by the County (Weld County I-25 Parallel Arterial Study, September 2003) as a major arterial
road(adjacent west of Filing 1) and requires a 140-foot right-of-way. The applicant shall verify the existing right-of-
way and the documents creating the right-of-way shall be noted on the final plat. If the right-of-way cannot be
verified, it will be dedicated on the final plat.
o A share (of the roadway cross-section) of CR 9 1/2 would be in the jurisdiction of Weld County and a
share (of the roadway cross-section) will be within the jurisdiction of Mead for Filing 1. The applicant
shall coordinate with the appropriate authority concerning respective rights-of-way and roadway
improvements meeting MUD criterion.
• The applicant shall provide written documentation of this coordination to Public Works prior to
scheduling a public hearing.
o The County anticipates coordination efforts between the applicant and Colorado Department of
Transportation(CDOT) for this timely project(CR 9 '/3).
Page 3 of 5
County Road 28 Construction Plans (CR 9 '/:to CR 111:
❑ General Note (Sheet GN1) #15 must be revised to a state fifteen (15%) percent maintenance bond shall be required.
This is a typographical error.
The engineer must address minimum centerline arc lengths use in the roadway design. Some centerline arc lengths
appear to short for an arterial roadway design.
❑ The engineer must address minimum K-values used for vertical curves (crest& sag). Some K-values are smaller than
anticipated for an arterial roadway.
❑ Sheet DT3 shall show more clearly details of ADA-compliant Ramps incorporating detectable warning surfaces
(ADAAG)2.
▪ 2 ADA Standards for Accessible Design,U.S. Department of Justice—Nondiscrimination on the Basis of Disability by
Public Accommodations and in Commercial Facilities,28 CFR—Part 36,Revised July 1, 1994.
❑ CR 28 has been annexed by the Town of Mead (adjacent at the north of Filing 1). The applicant shall verify the
existing right-of-way and the documents creating the right-of-way shall be noted on the final plat. If the right-of-way
cannot be verified,it will be dedicated on the final plat.
o CR 28 is gravel with sections maintained by Weld County and Mead in the vicinity of this development.
The applicant shall coordinate with the appropriate authority concerning respective roadway
improvements meeting MUD criterion.
• The applicant shall provide written documentation of this coordination to Public Works prior to
scheduling a public hearing.
o CR 28 must be improved for off-site development impacts with this Filing 1.
• CR 28 at the under-pass of 1-25 must be addressed, since it has been identified as unsafe by the
Department(off-site).
Internal Roadways:
a The tremendous scope of this proposal greatly exceeds Weld County's ability to serve and maintain internal roadway
infrastructure. The County recommends that a metro-district be formed to handle all internal roadways and
maintenance related matters for St. Vrain Lakes PUD.
t Easements shall be shown on the final plat in accordance with County standards (Sec.24-7-60) and / or Utility Board
recommendations.
❑ The Signage and Striping Plan (SS1-SS4) is generally acceptable, but shall be revised and resubmitted for acceptance
by Public Works. The stripping plan must include pavement marking details for roundabouts, driving lanes, bike
lanes, and parking. The striping plan must accurately detail the placement of stop bars and crosswalks at the
intersections. Markings for roundabouts must follow more closely the Manual on Uniform Traffic Control Devices
(MUTCD)recommendations for markings and signing. The applicant should coordinate revisions with Public Works.
Signing for all off-site improvements shall be addressed.
❑ The Lake Catamount Parkway& Eagle River Road Round-A-Bout Detail(Sheets DTI I, DT12)must be revised.
o Public Works recommends that a detectable warning surface, as recommended in the Americans with
Disabilities Act Accessibility Guidelines (ADAAG) §4.29 (Detectable Warnings), be applied to the
surface of the refuge within the splitter island'.
o The flare length should be a minimum of 80-feet for an urban design.
o The pedestrian crossing located within the splitter island should be 10-feet in length (cross-section B-B)
and a minimum of 6-feet in width. Dimensions must be clearly shown on the plan drawings.
o The total length of the splitter island envelope should be at least 50-feet to provide sufficient protection
for pedestrians and to alert approaching drivers to the roundabout geometry'.
o The engineer must provide roundabout details that accommodate bicyclists giving them a choice of
proceeding through the roundabout as either a vehicle or a pedestrian. A wider sidewalk to accommodate
both bicycles and pedestrians will be necessary, along with ADA-compliant ramps'. Ramp details must
be clearly referenced and additionally, should incorporate a detectable warning surface(ADAAG)2.
o Public Works recommends that all roundabouts be illuminated for an urban development. Plans detailing
illumination must be included with the construction drawings.
• 'Roundabouts: An Informational Guide, U.S. Department of Transportation — Federal Highway Administration,
Publication No.FHWA-RD-00-067,June 2000.
Page 4 of 5
•
• • 2 ADA Standards for Accessible Design, U.S. Department of Justice—Nondiscrimination on the Basis of Disability by
Public Accommodations and in Commercial Facilities,28 CFR—Part 36,Revised July 1, 1994.
❑ The applicant shall resubmit to Public Works stamped, signed and dated final roadway/construction & grading plan
drawings for acceptance. Each sheet must be sealed by the engineer of record, before the Department will permit the
case to proceed through the development process and before the plat may be recorded.
o This is consistent with County Code: Sec 24-3-50.
o Certified drawings will remain in the department's file for use during construction.
o The Public Works Department will need a total of sets of construction drawings= four(4).
• One set for case file
• One set for Stormwater/Drainage use
• Two sets for field inspectors
❑ The applicant or their agents may be required to obtain utility permits from Public Works' Utility Agent.
❑ Permits may be required for Development Construction, and Stormwater.
Recommendation
❑ The above comments are prerequisites and shall be fulfilled prior to scheduling a public hearing for the final plat.
Any issues shall be resolved with Public Works prior to recording of any final plat.'
•PCPF-1078 St.Vrain Lakes PUD-Filing I (Final Plan)
Email&Original:Planner:Kim Ogle
PC by Post: Applicant: Tyler Packard wl Carma Bayshore,LLC
PC by Post: Engineer:Fred Tafoya,Iq P.E.,Carroll&Lange,Inc.
Page 5 of 5
From: Chris.Fasching [Chris.Fasching@FHUENG.COM]
Sent: Friday, October 06, 2006 9:17 AM
To: Peter Schei; Drew Scheltinga
Subject: St Vrain Lakes Filing 1 Traffic Study
Follow Up Flag: Follow up
Flag Status: Completed
Peter and Drew,
Below are review comments on the St.Vrain Lakes Filing Traffic Study for your consideration.
1. The development proposal analyzed in the report includes 409 town home units,
300 K SF of government office, and 542 and single-family units. Please check that
this is consistent with the plans that are being submitted to your office.
2. For this filing,the trip generation is less than that estimated in the master traffic due to
the filing having fewer single-family units than originally identified and due to the
municipal complex being classified as a government office complex(rather than a
shopping center as was done in the master study). We think the reductions are
appropriate.
3. The study only considered short-term time frames(2009 in which only 70 units
would be complete and 2011), so presumably the master study is still the latest and
greatest document in addressing the long-term improvements in the area.
4. The 2009 time frame analysis assumed WCR 9.5 would partially exist; the segment
from WCR 28 to SH 66 would not be in yet. The 2011 time frame analysis does
include the WCR 9.5 completion to SH 66. This should be checked against the
current activity relative to the 1-25 widening and the associated relocation of the
frontage road to WCR 9.5 to ensure the timing of this road relocation is coordinated.
5. The intersection of SH 66/East Ramps/East Frontage Road was not analyzed in the
2009 time frame(prior to WCR 9.5 being completed). In fact, the study does not
recognize the Frontage Road s existence in the 2009 timeframe north of WCR 9.5.
Given the assumption that WCR 9.5 would not be complete to SH 66 in 2009, the
frontage road would need to remain. As such, the Frontage Road/WCR 28
intersection should be analyzed as should the Frontage Road/WCR 9.5 intersection
(near the St. Vrain River). Analyzing this intersection is not as critical for the 2011
timeframe provided that the 1-25 widening project(including the SH 66 interchange) is
complete(which also implies that the frontage road is no longer in place and that
WCR 9.5 is in place).
6. The study did not analyze the Frontage Road/WCR 28 intersection given the one-lane
tunnel. However, the study did recommend signalizing the intersection. It would be
helpful to know the projected traffic through the intersection and how a signal,
uniquely timed,would function here until 1-25 is widened.
10. The trip-distribution assumptions used may need more consideration. Relative to
trips heading west to or across 1-25, the following table illustrates assumptions used:
%traffic to/from I-25/SH 119 °/ci traffic to/from I-
25/SH 66
Master TIA 30-35% 20-30%
Filing 1 TIA, Year 2009 71% 4%
Filing 1 TIA, Year 2011 21% 43%
For year 2009, it seems that there was too much traffic assigned down to SH
119, but the 2011 time period analysis has significantly flip-flopped these such
that the heavy assignment is to SH 66. It is reasonable to expect a little
distribution difference between 2009 and 2011 since WCR 9.5 is not completed
in 2009 timeframe(or at least that is the assumption), but the"swing"in these
differences seems a bit strong. We would suggest to keep the distribution
percentages more in-line with those that we agreed to as part of the Master
Study. This change would require a re-do of the study
12. The intersection of WCR 9.5/Bayshore Drive will be very close to warranting a signal
by 2011. The master traffic study identified this as an eventual traffic signal; the year
2011 traffic numbers indicate that it will be close to being needed. It may be prudent for
the County to require escrow for this signal as part of Filing 1 in anticipation of the signal
going a few years later(once warrants are satisfied).
13. The WCR 28/WCR 9.5 intersection should be built to include a separate right turn
lane along the westbound approach to alleviate LOS problems. The study indicates that
improvements to this intersection will be done as part of Filing 2. In the event Filing 2 is
unexpectedly delayed, we suggest at least including this right turn lane or some means of
allowing right-turning traffic to by-pass the through and left turn movements.
14. One minor technical comment pertains to the existing traffic, Figure 3. It shows 500
vehicles per day along the frontage road north of SH 119; the true volume is more in the
2000 to 3000 vehicle per day range. Figure 14 actually represents this existing volume
more accurately.
Hopefully this helps out your review of Filing 1. If you need anything more from me,
please let me know.
Thanks
Chris Fasching
Felsburg Holt& Ullevig
303-721-1440
l--
44S(11
Weld County Referral
ISeptember 21, 2006
VI C.
COLORADO
The Weld County Department of Planning Services has received the following item for review:
Applicant Tom Morton Case Number PF-1078 - Filing One
Please Reply By October 20, 2006 Planner Kim Ogle
Project PUD Final Plan for 548 single family residential lots along with230 acres of opens
space and continuing Oil and Gas Production Uses (St. Vrain Lakes PUD)
Legal Part of Sections 35 and 36, T3N, R68W of the 6th P.M., Weld County, Colorado.
Location Multiple parcels generally located East of and adjacent to the I-25 Frontage Road,
and north of the St. Vrain River. For a more complete description see Legal.
Parcel Number 1207-36-000056, 1207-36-000031; 1207-36-000025; 1207-35-000051;
1207-35-000049 and 1207-35-000039
The application is submitted to you for review and recommendation. Any comments or recommendation you
consider relevant to this request would be appreciated. Please reply by the above listed date so that we may
give full consideration to your recommendation. Any response not received before or on this date may be
deemed to be a positive response to the Department of Planning Services. If you have any further questions
regarding the application, please call the Planner associated with the request. Please note that new
information may be added to applications under review during the review process. If you desire to
examine or obtain this additional information, please call the Department of Planning Services.
Weld County Planning Commission Hearing (if applicable) December 6, 2006
❑ We have reviewed the request and find that it does/does not comply with our Comprehensive Plan
❑ iWe have reviewed the request and find no conflicts with our interests.
ae See attached letter.
Comments:
Signature .Q Date /o- 06,/3 V
•
Agency l /lll/Zy r-v5iecTlah
❖ Weld County Planning Dept. •:• 4209 CR 24.5 Longmont,CO 80504 + (720)652 4210 ext.8730 4 (720)652 4211 fax
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DEPARTMENT OF PLANNING SERVICES
BUILDING INSPECTION
NORTH OFFICE
�^ (lilt 918 10th Street
Willie.
GREELEY, COLORADO 80631
PHONE (970)353-6100, EXT.3540
FAX (970) 304-6498
SOUTHWEST OFFICE
COLORADO 4209 CR 24.5
LONGMONT CO 80504
PHONE (720)652-4210 ext. 8730
FAX(720)652-4211
November 30, 2004
Tom Morton
PUD Final Plan for 548 single family residential lots along with 230 acres of open space and continuing Oil and Gas
Production Uses. (St.Vrains Lakes PUD)
PF-1078—Filing One
1. A separate building permit shall be obtained prior to the construction of any structure.
2. A plan review is required for each building for which a building permit is required. Plans shall include a floor
plan. Commercial building plans shall bear the wet stamp of a Colorado registered architect or engineer. Two
complete sets of plans are required when applying for each permit. Commercial building plans require a Code
Analysis Data sheet, provided by the Weld County Building Department.Residential building plans may be required
to bear the wet stamp of a Colorado registered architect or engineer.
3. Buildings shall conform to the requirements of the codes adopted by Weld County at the time of permit
application. Current adopted codes include the 2003 International Residential Code; 2003 International Building
Code;2003 International Mechanical Code;2003 International Plumbing Code;2003 International Fuel Gas Code;
2005 National Electrical Code and Chapter 29 of the Weld County Code.
4. Each building will require an engineered foundation based on a site-specific geotechnical report or an open hole
inspection performed by a Colorado registered engineer. Engineered foundations shall be designed by a Colorado
registered engineer.
5. Fire resistance of walls and openings,construction requirements,maximum building height and allowable areas
will be reviewed at the plan review. Setback and offset distances shall be determined by the Zoning Ordinance.
6. Building height shall be measured in accordance with the 2003 International Building Code for the purpose of
determining the maximum building size and height for various uses and types of construction and to determine
compliance with the Bulk Requirements from Chapter 23 of the Weld County Code. Building height shall be
measured in accordance with Chapter 23 of the Weld County Code in order to determine compliance with offset
and setback requirements. When measuring buildings to determine offset and setback requirements,buildings are
measured to the farthest projection from the building. Property lines shall be clearly identified and all property pins
shall be staked prior to the first site inspection.
7. A Flood Plain Development Permit will be required any building in the 100 year flood plain.
8. Provide a letter of approval from Mountain View Fire Protection District prior to construction.
9. There is one historical permit with final status and two active grading permits 2 on these parcels.
Please contact me for any further information regarding this project.
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Department
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TO: Kim Ogle, W.C. Planning OCT 3 j 2006
DATE: Octot7Departrn! St '
r'lupFROM: Pam
COLORADO Health and Environment
CASE NO.: Pi-1078 NAME: Carma Colorado/St. Vrain Lakes
I he Weld County Health Department has reviewed the Filing 1 Final Plan for this development and
offers the following comments:
On the St. Vrain Lakes Filing #1 Final Plat, page 2 of 33, the following plat notes have been omitted.
These plat notes have been recorded in the Change of Zone resolution as well.
Staff Resolution
Comments Number Comment
Number
Permanent restroom and handwashing facilities shall be provided
within easy access of all public gathering areas. At a minimum
3. F permanent, vaulted restroom facilities restroom facilities shall be
placed around the lake. A vault facility similar to a rest area or park
service facility is recommended.
The recreational uses on the lakes may be subject to the water
4. G quality standards of the Colorado Department of Public Health and
Environment Swimming Pool and Mineral Bath Regulations.
A stormwater discharge permit may be required for a
development/redevelopment construction site where a contiguous
5. H or non-contiguous land disturbance is greater than or equal to one
acre in area. Contact the Water Quality Control Division of the
Colorado Department of Public Health and the Environment at
www.cdphe.state.co.us/wq/PermitsUnit for more information.
"Weld County's Right to Farm"as provided in Appendix 22-E of the
9. L Weld County Code shall be placed on any recorded plat.
There are Confined Animal Feeding Operations in close proximity
10. M to this development. Residents should be aware that there may
be flies and odors associated with these activities.
O:\PAM\PLANNING\FINAL PLAT\PF-1078 CARMA-ST VRAIN LAKES.RTF
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