HomeMy WebLinkAboutDrainage Reports - 10/19/2015Octobe& 9, 2015
at of Ft. Collins rov Plans
' II
FINAL DRAINAGE AND
EROSION CONTROL REPORT FOR
MANHATTAN TOWNHOMES, SECOND FILING
Fort Collins, Colorado
1
,
A This Drainage Report is consciously provided as a PDF.
Please consider the environment before printing this document In Its entirety.
' When a hard copy is absolutely necessary, we recommend double -sided printing.
' NorthernEngineering.com //' 970.221.41,58
Prepared for:
Mosaic Real Estate
1021 Nightengale Dr.
Fort Collins, CO 80525
Prepared by:
PU NORTHERN
ENGINEERING
301 N. Howes St., Suite 100
Fort Collim, Colorado 80521
Phone: 970.221.4158 Fax: 970.221.4159
w .nonhemengineedng.com
Project .Number: 1124-001
NORTHERN
ENGINEERING
October 9, 2015
City of Fort Collins
Stormwater Utility
700 Wood Street
Fort Collins, Colorado 80521
RE: Final Drainage and Erosion Control Report for
MANHATTAN TOWNHOMES, SECOND HUNG
Dear Staff:
Northern Engineering is pleased to submit this Final Drainage and Erosion Control Report for your
review. This report accompanies the Project Development Plan submittal for the proposed
Manhattan Townhomes, Second Filing development.
This report has been prepared in accordance to Fort Collins Stormwater Criteria Manual (FCSCM),
and serves to document the stormwater impacts associated with the proposed project. We
understand that review by the City is to assure general compliance with standardized criteria
contained in the FCSCM.
If you should have any questions as you review this report, please feel free to contact us.
Sincerely,
NORTHERN ENGINEERING SERVICES, INC.
Aaron Cvar, PE
�
Project Engineer O, � � -6 •.. ��
.;.rti 'QS •. �s
301 N. Howes Street, Suite 100, Fort Collins, CO 86521 ( 970.221.4158 I www,northernengineering.com
NORTHERN
(.ENGINEERING
Manhattan To
TABLE OF CONTENTS .
I.
GENERAL LOCATION AND DESCRIPTION................................................................... 1
A.
Location.............................................................................................................................................1
B.
Description of Property...................:................................................................................................. 2
'
C.
Floodplain................................................................:.........................................................................3
II.
DRAINAGE BASINS AND SUB-BASINS.............................................................:......... 4
'
A.
Major Basin Description....................................................................................................................4
B.
Sub -Basin Description...............................................................................:..........I............................4
III.
DRAINAGE DESIGN CRITERIA.........................:........................................................ 5
'
A.
Regulations........................................................................................................................................5
B.
Four Step Process..............................................................................................................................5
'
C.
Development Criteria Reference and Constraints............................................................................5
'
D. Hydrological Criteria.........................................................................................................................6
E. Hydraulic Criteria..........................................................................................:...................................6
F. Modifications of Criteria.................................................:................................................................. 6
'
IV. DRAINAGE FACILITY DESIGN.................................................................................... 6
A. General Concept...............................................................................................................................6
'
B. Specific Details..................................................................................................................................7
V. CONCLUSIONS ............................. :..........................................................................9
'
A. Compliance with Standards..............................................................................................................9
B. Drainage Concept..............................................................................................................................9
APPENDICES:
APPENDIX A.1 - Hydrologic Computations
APPENDIX A.2 - Inlet Computations
APPENDIX A.3 - Storm Line Compuations
APPENDIX A.4 - Riprap Computations
'
APPENDIX B.1 - Erosion Control Report
APPENDIX C.1 - Standard Operating Procedures
APPENDIX D.1 - USDA Soils Report
'
APPENDIX E.1 - LID Conformance Report
MAP POCKET:
Proposed Drainage Exhibit
' Final Drainage Report
NORTHERN
ENGINEERING
u
I. GENERAL LOCATION AND DESCRIPTION
' A. Location
1: Vicinity Map
1
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1
Townhomes, Second Fili
2.
The project site is located in the Northeast Quarter of Section 35, Township 7 North,
'
Range 69 West of the 61 Principal Meridian, City of Fort Collins, County of Larimer,
State of Colorado.
t
3.
The project site is located just southeast of the intersection of Horsetooth Rd. and
Manhattan Ave.
4.
The project site lies within the Mail Creek Basin. The site is located adjacent to a
regional detention pond, which provides detention and water quality treatment for this
'
site as well as surrounding areas.
5.
As this is an infill site, the area surrounding the site is fully developed. The existing
'
Park South PUD lies to just to the west of the site; South Glen PUD lies just to the
the
south of site; Park South Commercial Plaza is just to the north of the site. An
existing regional detention pond and natural area exists adjacent to the site on the
'
east.
6.
No offsite flows enter the site from the north, south, west, or east. Two offsite basins
'
Final Drainage Report 1
tNORTHERN
ENGINEERING
' Manhattan Townhomes, Second Filing
(Basins OS1 and OS2) are identified on the Drainage Exhibit, which consist of
' adjacent right of way of Manhattan Avenue that drains to the proposed inlet located in
Manhattan Avenue near the southwest corner of the site. Flows from these offsite
basins stay within right of way and do not enter the project site.
' B. Description of Property
1. The development area is roughly 2.2 net acres.
1
1
Figure 1 — Aerial Photograph
2. The subject property is currently composed of vacant land. Existing ground slopes are
' mild to moderate (i.e., 1 - 6±%) through the interior of the property. General
topography slopes from west to east, directing historic undeveloped flows east into the
exsiting regional detention pond adjacent to the site.
' 3. According to the United States Department of Agriculture (USDA) Natural Resources
Conservation Service (NRCS) Soil Survey website:
http://websoilsurvey.nrcs.usda.gov/app/WebSoilSurvey.aspx,
the site consists of Nunn Clay Loam, which falls into Hydrologic Soil Group C and
Altvan-Santanta Loam, which falls into Hydrologic Soil Group B.
4. The proposed project site plan is composed of the development Townhome site.
' Associated site work, water, and sewer lines will be constructed with the
development. Onsite Low Impact Design (LID) features are proposed and will consist
Final Drainage Report 2
■�INORTHERN
ENGINEERING
Manhattan
of several features which are discussed in Section IV, below. .
13IRFMA,
I
Figure 2— Proposed Site Plan
Second Fili
5. There are no known irrigation laterals crossing the site.
6. The proposed land use is a Townhome Development.
C. Floodplain
7. No City or FEMA flood zones encroach the site or are located in vicinity of the site.
Final Drainage Report 3
' ■V (NORTHERN
ENGINEERING
i�
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1
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1�.—._ter-
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Manhattan T
Second
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Figure 3 —City of Fort Collins GIS Floodplain Mapping
(No Flood Zones Identified)
DRAINAGE BASINS AND SUB -BASINS
A. Major Basin Description
The project site lies within the Mail Creek Basin. The site is located adjacent to a
regional detention pond, which provides detention and water quality treatment for this
site as well as surrounding areas. The design of the regional pond assumed the
drainage area encompassed by the current project site as a contributory area as
documented in the previous design for the project site. This is documented in the
October 2005 report entitled, "Final Drainage and Erosion Control Report for
Manhattan Townhomes" (Ref.5). The current design of Manhattan Townhomes,
Second Filing, reduces runoff as compared to the original 2005 design. Onsite Low
Impact Design (LID) features are proposed and will consist of several features which
are discussed in Section IV, below.
B. Sub -Basin Description
1. The subject property historically drains overland generally from west to east. Runoff
from the majority of the site has historically been collected in the existing regional
detention pond located adjacent to the site to the east.
2. A more detailed description of the project drainage patterns is provided below.
Final Drainage Report 4
' ■V NORTHERN
ENGINEERING
' Manhattan Townhomes, Second Fili
III. DRAINAGE DESIGN CRITERIA
' A. Regulations
There are no optional provisions outside of the FCSCM proposed with the proposed
project.
B. Four Step Process
' The overall stormwater management strategy employed with the proposed project utilizes
the "Four Step Process" to minimize adverse impacts of urbanization on receiving waters.
The following is a description of how the proposed development has incorporated each
' step.
Step 1 — Employ Runoff Reduction Practices
Several techniques have been utilized with the proposed development to facilitate the
reduction of runoff peaks, volumes, and pollutant loads as the site is developed from the
current use by implementing multiple Low Impact Development (LID) strategies including:
' Conserving existing amenities in the site including the existing vegetated areas.
Providing vegetated open areas throughout the site to reduce the overall impervious
area and to minimize directly connected impervious areas (MDCIA).
Routing flows, to the extent feasible, through vegetated swales to increase time of
' concentration, promote infiltration and provide initial water quality.
Step 2 — Implement BMPs That Provide a Water Quality Capture Volume (WQCV) with
' Slow Release
The efforts taken in Step 1 will facilitate the reduction of runoff; however, urban
development of this intensity will still generate stormwater runoff that will require
' additional BMPs and water quality. The majority of stormwater runoff from the site will
ultimately be intercepted and treated using extended detention methods prior to exiting the
site.
' Step 3 — Stabilize Drainageways
There are no major drainageways within the subject property. While this step may not
' seem applicable to proposed development, the project indirectly helps achieve stabilized
drainageways nonetheless. By providing water quality treatment, where none previously
existed, sediment with erosion potential is removed from downstream drainageway
systems. Furthermore, this project will pay one-time stormwater development fees, as
' well as ongoing monthly stormwater utility fees, both of which help achieve City-wide
drainageway stability.
' Step 4 — Implement Site Specific and Other Source Control BMPs.
The proposed project will improve upon site specific source controls compared to historic
conditions:
' w The proposed development will provide LID and water quality treatment; thus,
eliminating sources of potential pollution previously left exposed to weathering and
runoff processes.
' C. Development Criteria Reference and Constraints
The subject property is surrounded by currently developed properties. Thus, several
' constraints have been identified during the course of this analysis that will impact the
proposed drainage system including:
' Final Drainage Report 5
.� NORTHERN
. I ENGINEERING
' Manhattan Townhomes, Second Filing
Existing elevations along the property lines will generally be maintained.
' As previously mentioned, overall drainage patterns of the existing site will be
maintained.
w Elevations of existing downstream facilities that the subject property will release to
twill be maintained.
D. Hydrological Criteria
' .1. The City of Fort Collins Rainfall Intensity -Duration -Frequency Curves, as depicted in
Figure RA-16 of the FCSCM, serve as the source for all hydrologic computations
associated with the proposed development. Tabulated data contained in Table RA-7
' has been utilized for Rational Method runoff calculations.
2. The Rational Method has been employed to compute stormwater runoff utilizing
coefficients contained in Tables RO-11 and RO-12 of the FCSCM. Please see
' Appendix A.
3. Three separate design storms have been utilized to address distinct drainage
scenarios. A fourth design storm has also been computed for comparison purposes.
' The first design storm considered is the 801h percentile rain event, which has been
employed to design the project's water quality features. The second event analyzed is
the "Minor," or "Initial" Storm, which has a 2-year recurrence interval. The third
' event considered is the "Major Storm," which has a 100-year recurrence interval.
The fourth storm computed, for comparison purposes only, is the 10-year event.
4. No other assumptions or calculation methods have been used with this development
' that are not referenced by current City of Fort Collins criteria.
E. Hydraulic Criteria
' 1. As previously noted, the subject property maintains historic drainage patterns.
2. All drainage facilities proposed with the project are designed in accordance with
' criteria outlined in the FCSCM and/or the Urban Drainage and Flood Control District
(UDFCD) Urban Storm Drainage Criteria Manual.
3. As stated above, the subject property is not located in any City or FEMA designated
' floodplains.
4. The proposed project does not propose to modify any natural drainageways.
' F. Modifications of Criteria
1. The proposed development is not requesting any modifications to criteria at this time.
IV. DRAINAGE FACILITY DESIGN
' A. General Concept
1. The main objectives of the project drainage design are to maintain existing drainage
patterns, and to ensure no adverse impacts to any adjacent properties.
' 2. LID features, which are discussed further below will be provided in order to enhance
water quality of storm runoff leaving the site. Detention and water quality capture
volume for the site is provided in the adjacent regional detention pond to the east.
' 3. Drainage patterns anticipated for drainage basins shown in the Drainage Exhibit are
' Final Drainage Report 6
'
NORTHERN
■� ENGINEERING Manhattan Townhomes Second Filing
described below.
'
Basin A
Basin A will generally drain via overland flow and via curb and gutter into Permeable
paver fields as discussed further in Section B, below. The permeable paver fields will
be designed such that minor storm flows will infiltrate into the paver systems; major
storm flows will partially infiltrate and the remainder of flows will be directed via
surface flow into the existing regional detention adjacent to the site, as shown on the
'
Drainage Exhibit. The permeable paver fields have been designed with underdrain
systems which daylight to the existing regional detention adjacent to the site.
Basin B & C
Basins B and C will generally drain via street curb and gutter to the proposed inlet in
Manhattan Avenue to be located near the southwest corner of the site. This inlet will
'
capture 100-year flows and convey flow via a storm line into the existing regional
detention pond adjacent to the site.
Basin OS1 and OS2
Basins OS1 and OS2 consist of adjacent right of way of Manhattan Avenue to the
north and to the south of the site which will drain to the proposed inlet in Manhattan
Avenue located near the southwest corner of the site. Flows from these basins will
'
stay within the right of way of Manhattan Avenue and will not enter the project site.
A full-size copy of the Drainage Exhibit can be found in the Map Pocket at the end of
'
this report.
B. Specific Details
'
1. Low Impact Design (LID) features are proposed within the site and include two
separate porous paver fields.
'
2. Permeable paver systems have been designed according to current City standards and
exceed current City requirements specifying a minimum of 25% of paved drive and
parking area being composed of porous pavers.
3. The paver systems have been designed with underdrain systems. The underdrain
systems have been designed to daylight to the existing detention
regional pond
located adjacent to the site to the east.
4. The following table summarizes LID features and overall percentage of the basin being
treated by the proposed LID features.
Final Drainage Report 7
■� I NORTHERN
ENGINEERING
I
1
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Manhattan T
Second
50% On -Site Treatment by LID Requirement
New Impervious Area
1.599
Ac.
Paver Area
0.136
Ac.
Traditional Pavement Area
0.438
Ac.
Other Impervious Surfaces (Roofs, Concrete Walks, etc.)
1.025
Ac.
Required Minimum Impervious Area to be Treated
0.800
Ac.
Paver LID Treatment
Paver area
0.136
Ac.
Run-on area for Pavers
0.358
Ac.
Impervious Area Treated by LID Pavers
0.495
Ac.
Rain Garden Treatment
Rain Garden Area
0.041
Ac.
Run-on area for Rain Garden
0.743
Ac.
Impervious Area Treated by Rain Gardens
0.784
Ac.
Total Impervious Area Treated
1.279
Ac.
Percent of Impervious Area Treated
79.98
%
25% Permeable Pavement Requirement
Sq.
New Pavement Area
24,426
Ft.
Sq.
Required Minimum Area of Permeable Pavement
6106
Ft.
Sq.
Total Permeable Pavement Area
5939
Ft.
Actual % of Permeable Pavement Provided
24.3
%
Table 1 — LID Summary Table
5. Standard Operating Procedures (SOP) Manual shall be provided to the City of
Fort Collins for review prior to Final Development Plan approval. A draft copy
of SOPs is provided in Appendix C. A final copy of the approved SOP manual
shall be provided to City by separate document and must be maintained on -
site by the entity responsible for the facility maintenance. Annual reports must
also be prepared and submitted to the City discussing the results of the
maintenance program 0e. inspection dates, inspection frequency, volume loss
due to sedimentation, corrective actions taken, etc.).
6. Proper maintenance of the drainage facilities designed with the proposed
development is a critical component of their ongoing performance and
effectiveness.
' final Drainage Report 8
■V INORTHERN
ENGINEERING Manhattan Townhomes, Second Filing
V. CONCLUSIONS
1 A. Compliance with Standards
1. The drainage design proposed with the proposed project complies with the City of Fort"
Collins' Stormwater Criteria Manual.
2. The drainage design proposed with this project complies with requirements for the Old
' Town Basin.
3. The drainage plan and stormwater management measures proposed with the
proposed development are compliant with all applicable State and Federal regulations
' governing stormwater discharge.
B. Drainage Concept
t 1. The drainage design proposed with this project will effectively limit any potential
damage associated with its stormwater runoff by providing detention and water
quality mitigation features.
' 2. The drainage concept for the proposed development is consistent with requirements
for the Old Town Basin.
' References
1. Fort Collins Stormwater Criteria Manual, City of Fort Collins, Colorado, as adopted by Ordinance No.
' 174, 2011, and referenced in Section 26-500 (c) of the City of Fort Collins Municipal Code.
2. Larimer County Urban Area Street Standards, Adopted January 2, 2001, Repealed and
Reenacted, Effective October 1, 2002, Repealed and Reenacted, Effective April 1, 2007.
3. Soils Resource Reoort for Larimer County Area Colorado, Natural Resources Conservation
' Service, United States Department of Agriculture.
4. Urban Storm Drainage Criteria Manual, Volumes 1-3, Urban Drainage and Flood Control
District, Wright -McLaughlin Engineers, Denver, Colorado, Revised April 2008.
' 5. Final Drainage and Erosion Control Report for Manhattan Townhomes, North Star Design,
October 2005.
1
' Final Drainage Report 9
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APPENDIX A.1
HYDROLOGIC COMPUTATIONS
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APPENDIX A.2
INLET COMPUTATIONS
17,
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INLET CAPACI SUMMARY
Project: 1124-001
By: ATC
Date: 6/1/2015
Inlet
Inlet
Inlet
Design
Design
Location
Type
Condition
Storm
Flow
Inlet Capacity
(CFS)
(CFS)
Manhattan Ave. Sump
Single Combination Inlet
Sump
100-yr
8.70
9.20
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INLET IN A SUMP OR SAG LOCATION
Project O 1124001
Inlet ID a Combo Inlet -Single
.F--Lo (C)--vr
HCuro
H-Vart
WO
Wp
W
WLo (G)
.1
Inlet Type
Cal Depression (additional to eordruon Older oopressbn'ofmm'O-Abut)
Orr
umber of Unit Iniats (Grata or Curb OPem6)
No
aerr Depth 0 F10wfae (outside of bad depression)
edam mute,
Flow Depth
-ergthofalldlGrate,
Nidth of a Unt Grab
W.
Van Opertrp Redo for a Grate (typical vehes 0.150.90)
A.
Factor for a Single Grab (typical vahs 0,50 - 0.70)
G (G):
a Weir Coefficient (typical vake 2.15 -3.60)
Cr (G)
Mier Orifice COeOdert (typical vela 0.60-0.80)
C=(G)=
ur0 OParJg Information
of a unit Cub OPerbe
L. R
eight Of Vertical Curb OperdM In bd>n
fl�'
eight of Cub Orifice Thoat In erhes
Hs m=
of Throat (see USDCM Fig" ST-6)
Tber
ide Width for Depression Pen (typlcaty the COW width of 2 feet)
Wr
bggaq Factor for a Shpb Cub Opobp Oypical vaka 0.10)
G (C)=
OParbp Weir Coefficient (typical vaka 2.33.6)
C. (C) _
OPWhV Orifice COefrdeni (typical vale 0.60 - 0.70)
C. (C)=
otal Inlet Interception Capacity (assumes clogged condition)
Q. _
bt C S GOOD for Fiber and eh or Storms aO PEAN
D r Arno =
W-Ing 1: Demmer, entered Is not a lypleal demembn for blot o,a aOeciflatl.
MINOR MAJOR
Darner No: 16 Combination'
2.00 2.00
1 1
8.0 1 12.0
3.00
3,00
2.00
2.00
0.31
0.31
0.50
0.50
3.60
160
0.60
0.60
3.00
3.00
6.50
6,50
5.25
5.25
0.00
0.00
2.00
2.00
0.10
0.10
3.70
3.70
0.66
0.66
des
Id es
ow
oot
' UD Inlet 3.1-Combo.bsm, Inlet in Sump 6/1212015, 125 PM
APPENDIX A.3
STORM LINE COMPUTATIONS
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APPENDIX A.4
RIPRAP COMPUTATIONS
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DRAINAGE CRITERIA MANUAL (V. 1)
Tt/U
MAJOR DRAINAGE
Use Da instead of D whenever flow is supercritical in the barrel.
**Use Type L for o distance of 3D downstream.
Figure MD-21—Riprap Erosion Protection at Circular Conduit Outlet Valid for Q/D2,5 5 6.0
Rev. 04/2008
Urban Drainage and Flood Control District
MD-107
MAJOR DRAINAGE
Yt/H
DRAINAGE CRITERIA MANUAL (V. 1)
Use Ha instead of H whenever culvert has supercritical flow in the barrel.
**Use Type L for a distance of 3H downstream.
Figure MD-22—Riprap Erosion Protection at Rectangular Conduit Outlet Valid for QIWW *5 5 8.0
9
04/2008
Urban Drainage and Flood Control District
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DRAINAGE CRITERIA MANUAL (V. 1)
9 = Expansion Angle
MAJOR DRAINAGE
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Figure MD-23—Expansion Factor for Circular Conduits
Rev. 04/2008
Urban Drainage and Flood Control District
MD-109
MAJOR DRAINAGE
8
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04/2008
Urban Drainage and Flood Control District
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APPENDIX B.1
EROSION CONTROL REPORT
.� INORTHERN
ENGINEERING
' Manhattan TownhomE
EROSION CONTROL REPORT
A comprehensive Erosion and Sediment Control Plan (along with associated details) HAS BEEN
PROVIDED BY SEPARATE DOCUMENT. It should be noted, however, that any such Erosion and
' Sediment Control Plan serves only as a general guide to the Contractor. Staging and/or phasing of
the BMPs depicted, and additional or different BMPs from those included may be necessary during
construction, or as required by the authorities having jurisdiction.
It shall be the responsibility of the Contractor to ensure erosion control measures are properly
maintained and followed. The Erosion and Sediment Control Plan is intended to be a living
' document, constantly adapting to site conditions and needs. The Contractor shall update the
location of BMPs as they are installed, removed or modified in conjunction with construction
activities. It is imperative to appropriately reflect the current site conditions at all times.
' The Erosion and Sediment Control Plan shall address both temporary measures to be implemented
during construction, as well as permanent erosion control protection. Best Management Practices
from the Volume 3, Chapter 7 — Construction BMPs will be utilized. Measures may include, but are
' not limited to, silt fencing along the disturbed perimeter, gutter protection in the adjacent roadways
and inlet protection at existing and proposed storm inlets. Vehicle tracking control pads, spill
containment and clean-up procedures, designated concrete washout areas, dumpsters, and job site
' restrooms shall also be provided by the Contractor.
Grading and Erosion Control Notes can be found on the Utility Plans. The Final Plans contain a
' full-size Erosion Control sheet as well as a separate sheet dedicated to Erosion Control Details. In
addition to this report and the referenced plan sheets, the Contractor shall be aware of, and adhere
to, the applicable requirements outlined in the Development Agreement for the development. Also,
the Site Contractor for this project will be required to secure a Stormwater Construction General
Permit from the Colorado Department of Public Health and Environment (CDPHE), Water Quality
Control Division — Stormwater Program, prior to any earth disturbance activities. Prior to securing
said permit, the Site Contractor shall develop a comprehensive StormWater Management Plan
' (SWMP) pursuant to CDPHE requirements and guidelines. The SWMP will further describe and
document the ongoing activities, inspections, and maintenance of construction BMPs.
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APPENDIX C.1
STANDARD OPERATING PROCEDURES
I
STANDARD OPERATING PROCEDURES (SOPS)
' MANHATTAN TOWNHOMES
A. Purpose
In order for physical stormwater Best Management Practices (BMPs) to be effective, proper maintenance is
essential. Maintenance includes both routinely scheduled activities, as well as non -routine repairs that may be
required after large storms, or as a result of other unforeseen problems. Standard Operating Procedures (SOPs)
' should clearly identify BMP maintenance responsibility. BMP maintenance is typically the responsibility of the
entity owning the BMP.
Identifying who is responsible for maintenance of BMPs and ensuring that an adequate budget is allocated for
' maintenance is critical to the long-term success of BMPs. Maintenance responsibility may be assigned either
publicly or privately. For this project, BMPs shown in Section B below noted as "Private" are to be maintained
by the property owner, homeowner's association (HOA), or property manager.
IB. Site -Specific SOPs
The following stormwater facilities contained within the Manhattan Townhomes development are subject to
' SOP requirements:
Permeable Modular Block Pavers (Private)
- Perforated Subdrain (Private)
' The location of said facilities can be found on the Utility Plans and Landscape Plans for the proposed project.
Inspection and maintenance procedures and frequencies, specific maintenance requirements and activities, as
' well as BMP-specific constraints and considerations shall follow the guidelines outlined in Volume 3 of the
Urban Drainage and Flood Control District (UDFCD) Urban Storm Drainage Criteria Manual.
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Permeable Modular Block Pavers (MBPs)
There is one MBP sections associated with the project serving the purpose of reducing runoff from the site as is required
by the City per their stated LID goals and ordinances. These systems provide storage and important water quality
benefits.
Proper maintenance is critical to ensure lasting performance and integrity of the system. The -more frequent and diligent
the routine maintenance procedures are, the more likely it is to avoid and/or postpone significant repair and replacement
actions. Such major remedies would include removal of the surface pavers to access (and potentially replace) the
underlying sub -base material and/or underdrain pipes should either become clogged or otherwise fail to function
properly.
For additional information on the maintenance of the Modular Block Pavers, refer to Section 5: Maintenance from
Permeable Interlocking Concrete Pavements, 4ch Edition (PICP Manual) by the Interlocking Concrete Pavement Institute.
Routine Maintenance Table for Permeable Pavement Systems
Required Action Maintenance Objective Frequency of Action
Inspect the pavement condition and
Inspection observe infiltration either during a rain
p event or with a garden hose to ensure that At least annually.
water infiltrates into the surface.
Debris Removal, Use a regenerative air or vacuum sweeper
As necessary - the frequency depends on use types
Sweeping and to maintain infiltration rates. Replace infill
(e.g., foot traffic only versus vehicle traffic) and
Vacuuming aggregate between pavers with #8
patterns as well as specific site conditions such as
crushed rock (3/8" washed).
tributary basin characteristics. Minimum Annually.
' DO NOT apply sand to the MBP surface.
Snow Removal Mechanical snow and ice removal should
be used.
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If the surface is completely clogged and
Full and Partial
rendering minimal surface infiltration rate,
Replacement of
restoration of surface infiltration can be
the Pavement or
achieved by removing the first'/z to 1 inch
Infill Material
of soiled aggregate infill material with a
vacuum sweeper. Refill the openings with
clean #8 aggregate infill materials.
As necessary.
Routine — Annual inspection of hydraulic and
structural facilities. Also check for obvious
problems during routine maintenance visits,
especially for plugging of outlets.
Trash Enclosure
Should stormwater leach out pollutants
Leakage, or other
g
from the trash enclosure area, or should
As necessary, based on routine observation and
other similar contaminants collect in the
Surface
Contamination/
inspection by the professional property
paver joint filler aggregate, said material
Pollution
management and maintenance contractor.
shall be removed and properly disposed
of, and replaced with new infill aggregate.
Page 2 of 3
Perforated Subdrain Maintenance Plan
' The perforated subdrain system within the Modular Block Paver (MBP) system is critical to the overall function of the
paver subbase. As such, special maintenance has been identified to ensure these perforated drain systems perform as
they were designed.
L-
1
Perforated subdrains leading away from the MBP system is designed to provide faster release of water when
accumulation occurs under the MBP system. Outflow should be seen existing the riser pipe outfall at the downstream
end of the subdrain pipe. If not seen it is recommended that the system is inspected using a video camera to verify no
clogging has occurred.
Perforated subdrains leading toward the MBP system are designed to provide an opportunity for infiltration. These
subdrains often lead to a drywell where additional infiltration capacity is available to reduce runoff per the stated LID
goals adopted by the City.
Routine Maintenance Table
Required Action Maintenance Objective Frequency of Action
Use a video camera to inspect the
condition of the perforated drain pipes.
Inspection Cleanout pipes as needed. If the integrity Every two to five years.
of the pipe is compromised, then repair
the damaged section(s).
Where accessible, expose inlet and/or
Inspection outlet of perforated pipe and watch for Minimum Annually
water inflow and/or outflow.
Page 3 of 3
APPENDIX D.1
USDA SOILS REPORT
I
United States
'
_USDA
Department of
Agriculture
MRCS
Natural
Resources
'
Conservation
Service
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A product of the National
Cooperative Soil Survey,
a joint effort of the United
States Department of
Agriculture and other
Federal agencies, State
agencies including the
Agricultural Experiment
Stations, and local
participants
Custom Soil Resource
Report for
Larimer County
Area, Colorado
' June 11, 2015
Preface
Soil surveys contain information that affects land use planning in survey areas. They
'
highlight soil limitations that affect various land uses and provide information about
the properties of the soils in the survey areas. Soil surveys are designed for many
different users, including farmers, ranchers, foresters, agronomists, urban planners,
community officials, engineers, developers, builders, and home buyers. Also,
conservationists, teachers, students, and specialists in recreation, waste disposal,
and pollution control can use the surveys to help them understand, protect, or enhance
the environment.
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Various land use regulations of Federal, State, and local governments may impose
special restrictions on land use or land treatment. Soil surveys identify soil properties
that are used in making various land use or land treatment decisions. The information
is intended to help the land users identify and reduce the effects of soil limitations on
various land uses. The landowner or user is responsible for identifying and complying
with existing laws and regulations.
Although soil survey information can be used for general farm, local, and wider area
planning, onsite investigation is needed to supplement this information in some cases.
Examples include soil quality assessments (http://www.nres.usda.gov/wps/portal/
nres/main/soils/health/) and certain conservation and engineering applications. For
more detailed information, contact your local USDA Service Center (http://
offices.sc.egov.usda.gov/locator/app?agency=nres) or your NRCS State Soil
Scientist (http://www.nres.usda.gov/wps/portal/nres/detail/soils/contactus/?
cid=nres142p2_053951).
Great differences in soil properties can occur within short distances. Some soils are
seasonally wet or subject to flooding. Some are too unstable to be used as a
foundation for buildings or roads. Clayey or wet soils are poorly suited to use as septic
tank absorption fields. A high water table makes a soil poorly suited to basements or
underground installations.
The National Cooperative Soil Survey is a joint effort of the United States Department
of Agriculture and other Federal agencies, State agencies including the Agricultural
Experiment Stations, and local agencies. The Natural Resources Conservation
Service (NRCS) has leadership for the Federal part of the National Cooperative Soil
Survey.
Information about soils is updated periodically. Updated information is available
through the NRCS Web Soil Survey, the site for official soil survey information.
The U.S. Department of Agriculture (USDA) prohibits discrimination in all its programs
and activities on the basis of race, color, national origin, age, disability, and where
applicable, sex, marital status, familial status, parental status, religion, sexual
orientation, genetic information, political beliefs, reprisal, or because all or a part of an
individual's income is derived from any public assistance program. (Not all prohibited
bases apply to all programs.) Persons with disabilities who require alternative means
for communication of program information (Braille, large print, audiotape, etc.) should
contact USDA's TARGET Center at (202) 720-2600 (voice and TDD). To file a
complaint of discrimination, write to USDA, Director, Office of Civil Rights, 1400
Independence Avenue, S.W., Washington, D.C. 20250-9410 or call (800) 795-3272
(voice) or (202) 720-6382 (TDD). USDA is an equal opportunity provider and
' employer.
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Contents
Preface....................................................................................................................2
HowSoil Surveys Are Made..................................................................................5
SoilMap..................................................................................................................7
SoilMap................................................................................................................8
Legend..................................................................................................................9
MapUnit Legend................................................................................................10
Map Unit Descriptions........................................................................................10
Larimer County Area, Colorado......................................................................12
3—Altvan-Satanta foams, 0 to 3 percent slopes.........................................12
74—Nunn clay loam, 1 to 3 percent slopes.................................................13
References............................................................................................................15
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How Soil Surveys Are Made
Soil surveys are made to provide information about the soils and miscellaneous areas
in a specific area. They include a description of the soils and miscellaneous areas and
'
their location on the landscape and tables that show soil properties and limitations
affecting various uses. Soil scientists observed the steepness, length, and shape of
the slopes; the general pattern of drainage; the kinds of crops and native plants; and
the
'
kinds of bedrock. They observed and described many soil profiles. A soil profile is
the sequence of natural layers, or horizons, in a soil. The profile extends from the
surface down into the unconsolidated material in which the soil formed or from the
surface down to bedrock. The unconsolidated material is devoid of roots and other
'
living organisms and has not been changed by other biological activity.
Currently, soils are mapped according to the boundaries of major land resource areas
(MLRAs). MLRAs are geographically associated land resource units that share
'
common characteristics related to physiography, geology, climate, water resources,
soils, biological. resources, and land uses (USDA, 2006). Soil survey areas typically
'
consist of parts of one or more MLRA.
The soils and miscellaneous in
areas a survey area occur in an orderly pattern that is
related to the geology, landforms, relief, climate, and natural vegetation of the area.
Each kind of soil and miscellaneous area is associated with a particular kind of
landform
or with a segment of the landform. By observing the soils and miscellaneous
areas in the survey area and relating their position to specific segments of the
landform, a soil scientist develops a concept, or model, of how they were formed. Thus,
during mapping, this model enables the soil scientist to predict with a considerable
'
degree of accuracy the kind of soil or miscellaneous area at a specific location on the
landscape.
Commonly, individual soils on the landscape merge into one another as their
characteristics gradually change. To construct an accurate soil map, however, soil
scientists must determine the boundaries between the soils. They can observe only
a limited number of soil profiles. Nevertheless, these observations, supplemented by
'
an understanding of the soil -vegetation -landscape relationship, are sufficient to verify
predictions of the kinds of soil in an area and to determine the boundaries.
Soil scientists recorded the characteristics of the soil profiles that they studied. They
noted texture,
'
soil color, size and shape of soil aggregates, kind and amount of rock
fragments, distribution of plant roots, reaction, and other features that enable them to
identify soils. After describing the soils in the survey area and determining their
properties, the soil scientists assigned the soils to taxonomic Gasses (units).
'
Taxonomic classes are concepts. Each taxonomic class has a set of soil
characteristics with precisely defined limits. The classes are used as a basis for
comparison to classify soils systematically. Soil taxonomy, the system of taxonomic
'
classification used in the United States, is based mainly on the kind and character of
soil properties and the arrangement of horizons within the profile. After the soil
scientists classified and named the soils in the survey area, they compared the.
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Custom Soil Resource Report
individual soils with similar soils in the same taxonomic class in other areas so that
they could confirm data and assemble additional data based on experience and .
'
research.
The objective of soil mapping is not to delineate pure map unit components; the
objective is to separate the landscape into landforms or landform segments that have
'
similar use and management requirements. Each map unit is defined by a unique
combination of soil components and/or miscellaneous areas in predictable
proportions. Some components may be highly contrasting to the other components of
the
'
map unit. The presence of minor components in a map unit in no way diminishes
the usefulness or accuracy of the data. The delineation of such landforms and
landform segments on the map provides sufficient information for the development of
resource plans. If intensive use of small areas is planned, onsite investigation is
needed to define and locate the soils and miscellaneous areas.
Soil scientists make many field observations in the process of producing a soil map.
The frequency of observation is dependent upon several factors, including scale of
'
mapping, intensity of mapping, design of map units, complexity of the landscape, and
experience of the soil scientist. Observations are made to test and refine the soil -
landscape model and predictions and to verify the classification of the soils at specific
locations. Once
'
the soil -landscape model is refined, a significantly smaller number of
measurements of individual soil properties are made and recorded. These
measurements may include field measurements, such as those for color, depth to
bedrock, and texture, and laboratory measurements, such as those for content of
'
sand, silt, day, salt, and other components. Properties of each soil typically vary from
one point to another across the landscape.
Observations for map unit components are aggregated to develop ranges of
'
characteristics for the components. The aggregated values are presented. Direct
measurements do not exist for every property presented for every map unit
component. Values for some properties are estimated from combinations of other
'
properties.
While a soil survey is in progress, samples of some of the soils in the area generally
are collected for laboratory analyses and for engineering tests. Soil scientists interpret
the data from these analyses and tests as well as the field -observed characteristics
and the soil properties to determine the expected behavior of the soils under different
uses. Interpretations for all of the soils are field tested through observation of the soils
in different uses and under different levels of management. Some interpretations are
'
modified to fit local conditions, and some new interpretations are developed to meet
local needs. Data are assembled from other sources, such as research information,
production records, and field experience of specialists. For example, data on crop
'
yields under defined levels of management are assembled from farm records and from
field or plot experiments on the same kinds of soil.
Predictions about soil behavior are based not only on soil properties but also on such
'
variables as climate and biological activity. Soil conditions are predictable over long
periods of time, but they are not predictable from year to year. For example, soil
scientists can predict with a fairly high degree of accuracy that a given soil will have
a high water table within certain depths in most years, but they cannot predict that a
'
high water table will always be at a specific level in the soil on a'specific date.
After soil scientists located and identified the significant natural bodies of soil in the
survey area, they drew the boundaries of these bodies on aerial photographs and
'
identified each as a specific map unit. Aerial photographs show trees, buildings, fields,
roads, and rivers, all of which help in locating boundaries accurately.
u
Soil Ma
The soil map section includes the soil map for the defined area of interest, a list of soil
' map units on the map and extent of each map unit, and cartographic symbols
displayed on the map. Also presented are various metadata about data used to
produce the map, and a description of each soil map unit.
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Custom Soil Resource Report
Soil Map
.-1. "y Iu 49303D 493051D 493070 493090
b
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MaD Sale: 1:1,120 g pdrited on A Mt-e (8.5 x 11") sheet. 1�
NN 0 15 3D 50 90
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200 300
MV prq"m: Web Mentor Curie-mordrkim: WGS84 Edge tics: urm Zone 13N WGS84
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MAP LEGEND MAP INFORMATION
Anse of Inters if (AOI) 12 Spot[ Area The soil surveys that comprise your AOI Were mapped at 1:24,0D0.
Area of lnte.est(A01)
d Stony Spot
Soils Warni :Soil Ma m
Very Stony Spot n0 P may not be vad at this scale.
Soil Map Uni: Polygons
Wet Spot
.. Soil Map Unit Lines Enlargement of maps beyond Me wale of mapping can cause
p Other misunderstanding of the detall of mapping and accuracy of soil line
Soil Map Unit Points placement. The maps do not show Me small areas of contrasting
.� Special Lina Features sots that could have been shown at a more detailed scale.
Special Pant Feetuns
V Blowout Water FaaWro
Borrow Pit Streems and Canals Pleax rely on the bar scale on each map sheet for map
Iran tporoeon ntBasMrenrents
p( Gay Spot Ica Rails
0 Closed Depression Source of Map: Natural Resources Conservation Service
.v interstate highways Web Soil Survey URL: http://websoilsuNey.nrm,usda.gov
Grovel Pit US Routes Coordinate System: Web Mercator (EPSG:3857)
Gravelly Spot = Major Roads
Maps from the Web Sol Survey are based on the Web Mercator
Landfall Loral Roads Pmlecti0 n, which preserves direction and shape but distorts
Lave Flow, distance and area A projection that preserves area, such as the
Background Albers equal-area conic projection, should be used If more accurate
4L Marsh or swamp n Aadel Photography ralandatiorl5 of distance or area are required
Mine or Quarry
This product is generated from the USDA-NRCS certified data as of
it Miscellaneous Ware, the version date(s) listed below.
Perennial Water
r< Rock omcrop Sal Survey Area Lanmer County Area. Colorado
Survey Area Data Version 9, Sep 22, 2014
+ Sauna spot
Sandy Spot Soil map unls are labeled (as space allows) for map scales 1:50,000
or larger
,ill Severely Eroded Soot
Sinkhole Datets) salted images were photographed Apr22,2011—Apr28,
2011
Slide or Slip
f Soar Spol The orlrophalo or other base map on which the soil lines were
Compiled and digitized probably offers from the background
imagery, displayed on these maps. As a result, some minor shifting
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' Map Unit Legend
11
Lorimer County Area, Colorado (CO644)
Map Unit Symbol
Map Unit Name
Acres in AOI
Percent of A01
3
Altvan-Satanta loams, 0 to 3
percent slopes
1.5
41.9%
74
Nunn day loam, 1 to 3 percent
slopes
2.0
58.1%
Totals for Area of Interest
3.5
100.0%
Map Unit Descriptions
The map units delineated on the detailed soil maps in a soil survey represent the soils
'
or miscellaneous areas in the survey area. The map unit descriptions, along with the
maps, can be used to determine the composition and properties of a unit.
A map unit delineation on a soil map represents an area dominated by one or more
'
major kinds of soil or miscellaneous areas. A map unit is identified and named
according to the taxonomic classification of the dominant soils. Within a taxonomic
class there are precisely defined limits for the properties of the soils. On the landscape,
'
however, the soils are natural phenomena, and they have the characteristic variability
of all natural phenomena. Thus, the range of some observed properties may extend
beyond the limits defined for a taxonomic class. Areas of soils of a single taxonomic
class rarely, if ever, can be mapped without including areas of other taxonomic
'
classes. Consequently, every map unit is made up of the soils or miscellaneous areas
for which it is named and some minor components that belong to taxonomic classes
other than those of the major soils.
'
Most minor soils have properties similar to those of the dominant soil or soils in the
map unit, and thus they do not affect use and management. These are called
noncontrasting, or similar, components. They may or may not be mentioned in a
'
particular map unit description. Other minor components, however, have properties
and behavioral characteristics divergent enough to affect use or to require different
management. These are called contrasting, or dissimilar, components. They generally
are in small areas and could not be mapped separately because of the scale used.
'
Some small areas of strongly contrasting soils or miscellaneous areas are identified
by a special symbol on the maps. If included in the database for a given area, the
contrasting minor components are identified in the map unit descriptions along with
some characteristics of each. A few areas of minor components may not have been
'
observed, and consequently they are not mentioned in the descriptions, especially
where the pattern was so complex that it was impractical to make enough observations
'
to identify all the soils and miscellaneous areas on the landscape.
The presence of minor components in
a map unit in no way diminishes the usefulness
or accuracy of the data. The objective of mapping is not to delineate pure taxonomic
classes but rather to separate the landscape into landforms or landform segments that
have
'
similar use and management requirements. The delineation of such segments
on the map provides sufficient information for the development of resource plans. If
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intensive use of small areas is planned, however, onsite investigation is needed to
define and locate the soils and miscellaneous areas.
An identifying symbol precedes the map unit name in the map unit descriptions. Each
description includes general facts about the unit and gives important soil properties
and qualities.
Soils that have profiles that are almost alike make up a soil series. Except for
differences in texture of the surface layer, all the soils of a series have major horizons
that are similar in composition, thickness, and arrangement.
Soils of one series can differ in texture of the surface layer, slope, stoniness, salinity,
degree of erosion, and other characteristics that affect their use. On the basis of such
differences, a soil series is divided into soil phases. Most of the areas shown on the
detailed soil maps are phases of soil series. The name of a soil phase commonly
indicates a feature that affects use or management. For example, Alpha silt loam, 0
to 2 percent slopes, is a phase of the Alpha series.
Some map units are made up of two or more major soils or miscellaneous areas.
These map units are complexes, associations, or undifferentiated groups.
A complex consists of two or more soils or miscellaneous areas in such an intricate
pattern or in such small areas that they cannot be shown separately on the maps. The
pattern and proportion of the soils or miscellaneous areas are somewhat similar in all
areas. Alpha -Beta complex, 0 to 6 percent slopes, is an example.
An association is made up of two or more geographically associated soils or
miscellaneous areas that are shown as one unit on the maps. Because of present or
anticipated uses of the map units in the survey area, it was not considered practical
or necessary to map the soils or miscellaneous areas separately. The pattern and
relative proportion of the soils or miscellaneous areas are somewhat similar. Alpha -
Beta association, 0 to 2 percent slopes, is an example.
An undifferentiated group is made up of two or more soils or miscellaneous areas that
could be mapped individually but are mapped as one unit because similar
interpretations can be made for use and management. The pattern and proportion of
the soils or miscellaneous areas in a mapped area are not uniform. An area can be
made up of only one of the major soils or miscellaneous areas, or it can be made up
of all of them. Alpha and Beta soils, 0 to 2 percent slopes, is an example.
Some surveys include miscellaneous areas. Such areas have little or no soil material
and support little or no vegetation. Rock outcrop is an example.
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Larimer County Area, Colorado
3—Altvan-Satanta loams, 0 to 3 percent slopes
Map Unit Setting
National map unit symbol. jpw2
Elevation: 5,200 to 6,200 feet
Mean annual precipitation: 13 to 15 inches
Mean annual air temperature: 48 to 50 degrees F
Frost -free period: 135 to 150 days
Farmland classification: Prime farmland if irrigated
Map Unit Composition
Altvan and similar soils: 45 percent
Satanta and similar soils: 30 percent
Estimates are based on observations, descriptions, and transacts of the mapunit.
Description of Altvan
1 Setting
Landform: Benches, terraces
Landform position (three-dimensional): Side slope, tread
1 Down -slope shape: Linear
Across -slope shape: Linear
Parent material. Mixed alluvium
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Typical profile
H1 - 0 to 10 inches:
H2 - 10 to 18 inches:
H2 - 10 to 18 inches:
H2 - 10 to 18 inches:
H3 - 18 to 30 inches:
H3 - 18 to 30 inches:
H3 - 18 to 30 inches:
H4 - 30 to 60 inches:
H4 - 30 to 60 inches:
H4 - 30 to 60 inches:
Properties and qualities
loam
clay loam, loam, sandy clay loam
loam, fine sandy loam, silt loam
gravelly sand, gravelly coarse sand, coarse sand
Slope: 0 to 3 percent
Depth to restrictive feature: More than 80 inches
Natural drainage class: Well drained
Runoff class: Low
Capacity of the most limiting layer to transmit water (Ksat): Moderately high to high
(0.60 to 2.00 in/hr)
Depth to water table: More than 80 inches
Frequency of flooding. None
Frequency of ponding: None
Calcium carbonate, maximum in profile: 10 percent
Available water storage in profile: Very high (about 13.2 inches)
Interpretive groups
1 Land capability classification (irrigated): 3e
Land capability classification (nonimgated): 3e
Hydrologic Soil Group: B
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Custom Soil Resource Report
Description of Satanta
Setting
Landform: Terraces, structural benches
Landform position (three-dimensional): Side slope, tread
Down -slope shape: Linear
Across -slope shape: Linear
Parent material Mixed alluvium and/or eolian deposits
Typical profile
H1 - 0 to 9 inches: loam
H2 - 9 to 18 inches: loam, clay loam, sandy clay loam
H2 - 9 to 18 inches: loam, clay loam, fine sandy loam
H2 - 9 to 18 inches.
H3 - 18 to 60 inches:
H3 - 18 to 60 inches.
H3 - 18 to 60 inches:
Properties and qualities
Slope: 0 to 1 percent
Depth to restrictive feature: More than 80 inches
Natural drainage class: Well drained
Runoff class. Low
Capacity of the most limiting layer to transmit water (Ksat):
(0.60 to 2.00 in/hr)
Depth to water table: More than 80 inches
Frequency of flooding. None
Frequency of ponding. None
Moderately high to high
Ca/aum carbonate, maximum in profile: 10 percent
Available water storage in profile: Very high (about 27.4 inches)
Interpretive groups
Land capability classification (irrigated): 1
Land capability classification (nonirrigated): 3c
Hydrologic Soil Group: B
74—Nunn clay loam, 1 to 3 percent slopes
Map Unit Setting
' National map unit symbol. jpxn
Elevation: 4,800 to 5,600 feet
Mean annual precipitation: 13 to 15 inches
Mean annual air temperature: 48 to 50 degrees F
' Frost -free period. 135 to 150 days
Farmland classification: Prime farmland if irrigated
' Map Unit Composition
Nunn and similar soils: 85 percent
Estimates are based on observations,
13
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descriptions, and transacts of the mapunit.
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Custom Soil Resource Report
Description of Nunn
Setting
Landform: Fans, terraces
Landform position (three-dimensional): Base slope, tread
Down -slope shape: Linear
Across -slope shape: Linear
Parent material: Alluvium
Typical profile
H1- 0 to 10 inches. clay loam
H2 - 10 to 60 inches. clay loam, clay
H2 - 10 to 60 inches:
Properties and qualities
Slope: 1 to 3 percent
Depth to restrictive feature: More than 80 inches
Natural drainage class. Well drained
Runoff class: High
Capacity of the most limiting layer to transmit water (Ksat): Moderately low to
moderately high (0.06 to 0.20 in/hr)
Depth to water table: More than 80 inches
Frequency of flooding. None
Frequency of ponding: None
Calcium carbonate, maximum in prorile: 15 percent
Salinity, maximum in profile: Nonsaline to very slightly saline (0.0 to 2.0 mmhos/cm)
Available water storage in prorile: Very high (about 18.9 inches)
Interpretive groups
Land capability classification (irrigated): 2e
Land capability classification (nonirrigated): 3e
Hydrologic Soil Group: C
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References
American Association of State Highway and Transportation Officials (AASHTO). 2004.
Standard specifications for transportation materials and methods of sampling and
testing. 24th edition.
American Society for Testing and Materials (ASTM). 2005. Standard classification of
soils for engineering purposes. ASTM Standard D2487-00.
Cowardin, L.M., V. Carter, F.C. Golet, and E.T. LaRoe. 1979. Classification of
wetlands and deep -water habitats of the United States. U.S. Fish and Wildlife Service
FWS/OBS-79/31.
Federal Register. July 13, 1994. Changes in hydric soils of the United States.
Federal Register. September 18, 2002. Hydric soils of the United States.
Hurt, G.W., and L.M. Vasilas, editors. Version 6.0, 2006. Field indicators of hydric soils
in the United States..
National Research Council. 1995. Wetlands: Characteristics and boundaries.
Soil Survey Division Staff. 1993. Soil survey manual. Soil Conservation Service. U.S.
Department of Agriculture Handbook 18. hftp://www.nres.usda.gov/wps/portal/nres/
detail/nationa I/soils/?cid=nres 142p2_054262
Soil Survey Staff. 1999. Soil taxonomy: A basic system of soil classification for making
and interpreting soil surveys. 2nd edition. Natural Resources Conservation Service,
U.S. Department of Agriculture Handbook436. hftp://www.nres.usda.gov/wps/portal/
nres/detail/national/soils/?cid=nres 142p2_053577
Soil Survey Staff. 2010. Keys to soil taxonomy. 11th edition. U.S. Department of
Agriculture, Natural Resources Conservation Service. hftp://www.nres.usda.gov/wps/
portal/nres/detail/national/soils/?cid=nres 142p2_053580
Tiner, R.W., Jr. 1985. Wetlands of Delaware. U.S. Fish and Wildlife Service and
Delaware Department of Natural Resources and Environmental Control, Wetlands
Section.
United States Army Corps of Engineers, Environmental Laboratory. 1987. Corps of
Engineers wetlands delineation manual. Waterways Experiment Station Technical
Report Y-87-1.
United States Department of Agriculture, Natural Resources Conservation Service.
National forestry manual. hftp://www.nres.usda.gov/wps/portal/nres/detail/soils/
home/?cid=nres 142p2_053374
United States Department of Agriculture, Natural Resources Conservation Service.
National range and pasture handbook. hftp://www.nres.usda.gov/wps/portal/nres/
detail/national/landuse/rangepasture/?cid=stel prdb l 043084
u
15
Custom Soil Resource Report
United States Department of Agriculture, Natural Resources Conservation Service.
National soil survey handbook, title 430-VI. hftp://www.nres.usda.gov/wps/portal/
nres/detail/soils/scientists/?cid=nres 142p2_054242
United States Department of Agriculture, Natural Resources Conservation Service.
2006. Land resource regions and major land resource areas of the United States, the
Caribbean, and the Pacific Basin. U.S. Department of Agriculture Handbook 296.
hftp://www. nres. usda. gov/wps/portal/nres/detail/national/soils/?
cid=nres 142p2_053624
United States Department of Agriculture, Soil Conservation Service. 1961. Land
capability classification. U.S. Department of Agriculture Handbook 210. http:H
www.nrcs.usda.gov/lntemet/FSE—DOCUMENTS/nrcsl42p2_052290.pdf
I
16
APPENDIX E.1
LID CONFORMANCE REPORT
NORTHERN
ENGINEERING
LID Conformance Report
Date: October 6, 2015
Project: Manhattan Townhomes — Second Filing Project No. 1124-001
Fort Collins, CO
' Attn: Stormwater Staff
City of Fort Collins Stormwater Utility
700 Wood Street
Fort Collins, CO 80521
Stormwater Staff:
' This letter serves to document conformance of the above referenced project with City of Fort Collins Low
Impact Development (LID) requirements. In particular, the project is meeting Section 3.1 of the Fort Collins
Stormwater Amendments to the Urban Drainage and Flood Control District Criteria Manual, including Section
' 3.1 (a)(1) requiring that no less than 50% of any newly added impervious area be treated using one or more
LID techniques and Section 3.1(a)(2) requiring that no less than 25% of all new paving use a permeable
pavement technology that is considered an LID technique.
Section 3.1(a)(1)
The project as a whole is proposing 1.599 acres of new impervious area. This results in a minimum required
LID treatment area of 0.800 acres. The project is providing 0.495 acres of impervious area treated by
' pavers (directly or indirectly), and is treating 0.784 acres of impervious areas using rain gardens. The total
project area treated by LID techniques is 1.279 acres, which is 80% of the total new impervious area.
Section 3.1(a)(2)
The project as a whole is proposing 24,426 sf of new impervious paving. This results in a minimum required
permeable paving area of 6,106 sf. The project has evaluated various areas for pavers, and has determined
that the most logical placement is along the entire southern entry drive. A second small paver field has been
' provided at the north entrance as well. The total area of permeable pavers provided by the project is 5,939
sf, which is 24.3% of the total new paving. While this is slightly below the minimum required, the southern
drive area has been chosen due to it being the low point of the parking area, thereby increasing the run-on
areas of paving that can be treated. Both areas also coincide with logical limits of the site, which enhances
' the overall treatment provided and reduces overall maintenance in the future.
I`J
An exhibit has been provided to illustrate the topics outlined, and calculations supporting the rain garden
sizing are also included. Please feel free to contact me if you have any questions.
Sincerely,
Andrew Reese
Project Engineer
1
301 N. Howes Street, Suite 100, Fort Collins, CO 80521 I 970.221.4158 I www.northemengineering.com
u
MAP POCKET
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