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Drainage Report
for
CVS PHARMACY
Rangeline Road and Medical Drive
Carmel, Hamilton County, Indiana
Prepared For:
GB Indiana 2, LLC
600 East 96 Street, Suite 150
Indianapolis, Indiana 46240
Prepared By:
American Structurepoint, Inc.
7260 Shadeland Station
Indianapolis, Indiana 46256
Shaun A. Cofer, PE, LEED AP
Daniel J. Kmiecik, EI
Prepared: October 14, 2009
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Shadeland Station indianapo s IN 46.56-39 TEL,31,7 547 55 80. 'FAX 317.543 02 70 www structurepomt co!
AMERICAN STRUCTUREPOINT, INC.
PROJECT NARRATIVE
I. Project Description
II. Existing Drainage
III. Proposed Drainage
IV. Storm Sewer Design
V. Stormwater Quality
VI. Summary and Conclusions
APPENDICES
Appendix A Project Location Map
Appendix B
Appendix C Soils Data
Appendix D
Appendix E
Appendix F
Appendix G
Appendix H
Appendix I
Appendix J
TABLE OF CONTENTS
Flood Insurance Rate Map
Existing Conditions Drainage Basins
Existing Conditions Runoff Calculations
Proposed Conditions Drainage Basins
Proposed Conditions Runoff Calculations
Proposed Storm Sewer Inlet Basins
Proposed Storm Sewer Design Calculations
Proposed Water Quality Calculations
1N20060188
AMERICAN STRUCTUREPOINT, INC.
I. PROJECT DESCRIPTION
DRAINAGE REPORT
for
CVS PHARMACY
Rangeline Road and Medical Drive
Carmel, Hamilton County, Indiana
The proposed project is located at the northwest corner of the intersection of Rangeline Road and Medical
Drive in Carmel, Hamilton County, Indiana. The site consists of approximately 1.191 acres of developed
residential/commercial property at this intersection that will be razed and redeveloped to the proposed use. The
property currently contains a 1 -story CVS/Pharmacy and a 1 -story Taco Bell. A location map can be found in
Appendix A.
The project site is located in the unshaded Zone "X" (areas determined to be outside the 500 -year floodplain),
as indicated on the attached Hamilton County, Indiana, Flood Insurance Rate Map 18057CO209F, dated
February 19, 2003, found in Appendix B.
The property will be redeveloped to accommodate a 13,013 -sft CVS Pharmacy building and associated
infrastructure. The CVS building will include a 2 -lane drive- through service, as well as a 63 -space parking lot.
There will be one driveway into the site from Rangeline Road on the west side of the site and one driveway
providing access on the south side of the site via Medical Drive.
II. EXISTING DRAINAGE
The current property is a developed site that contains two commercial buildings and parking lots. The majority
of runoff from the site flows to the southeast toward the entry driveway located on Medical Drive where it is
conveyed to the east. A very small amount of runoff from the parkway area is distributed west to Rangeline
Road.
The Natural Resources Conservation Service (MRCS) Web Soil Survey of Hamilton County, Indiana, indicates
Brookston silty clay loam, Crosby silt loam, and Miami silt loam are on site. A soils map can be found in
Appendix C.
The existing drainage calculations evaluate the site as having one discharge point, because the majority of
runoff is going toward the southeast side of the site to Medical Drive. The time of concentrations for the overall
basin has been evaluated using sheet and shallow flows and shallow concentrated flows across the site to the
Medical Drive entry drive. An existing drainage basin map of the existing site is provided in Appendix D. The
existing site discharges were found to be 7.25 cfs and 12.36 cfs for the 10 -year and 100 -year storm events,
respectively.
Calculations for the existing drainage conditions were produced using HydroCAD Version 9.00 by HydroCAD
Software Solutions, LLC, and can be found in Appendix E.
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AMERICAN STRUCTUREPOINT, INC.
III. PROPOSED DRAINAGE
Once the site is fully redeveloped, runoff from the site will be collected in an on -site storm sewer system. An
overall drainage area map can be found in Appendix F. The stormwater will be conveyed through the on -site
storm sewer system to an underground detention system. The underground detention system will provide
storage during large rain events so the proposed discharge from the site is not greater than the allowable site
discharges found in the City of Carmel Stormwater Technical Standards Manual. The underground detention
system has been sized to accommodate these regulations. The allowable discharge for the site is 0.1 cfs per
acre for the 10 -year storm and 0.3 cfs per acre for the 100 -year storm. The underground detention system has
been sized for these standards, and the calculated discharge can be found in the summary table below.
The calculated conditions show a peak 100 -year stage elevation of 827.71. The City of Carmel Stormwater
Technical Standards Manual also states that the minimum orifice size to be used on site is six inches. Using a
minimum 6 -inch orifice, the model was run again and the "actual discharge" can be found in the summary table
below.
The actual conditions showed a peak 100 -year stage elevation of 826.33. Calculations for the proposed
drainage conditions were produced using HydroCAD Version 9.00 by HydroCAD Software Solutions, LLC,
and can be found in Appendix G.
IV. STORM SEWER DESIGN
The storm sewer system has been designed based on a 10 -year storm event in accordance with the City of
Carmel Stormwater Technical Standards Manual. A storm sewer basin map of the proposed site can be found
in Appendix H, and the design calculations can be found in Appendix I of this report.
V. STORMWATER QUALITY
The City of Carmel Stormwater Technical Standards Manual states that the flow through BMP sizing
calculation is found by determining a CNwq value for the site and using that value for a 1 -inch, 24- hour storm
event. All stormwater runoff from the site will discharge into a stormwater quality treatment unit known as an
AquaSwirl Storm Water Quality Unit. This hydraulic chamber separation method will capture the required
80 percent total suspended solids, along with other floating debris and hydrocarbons, prior to discharging into
the downstream storm system. An AS -6 AquaSwirl model has been selected to treat a maximum flow rate of
1.80 cfs per Table 1 of the City of Indianapolis SQU Selection Guide. This AS -6 SWQU will effectively
provide treatment not only for the first flush, but also for all rainfall events up to and including the 100 -year
storm event. The AS -6 Aquaswirl model is an ideal fit for this development. The design calculations can be
found in Appendix J of this report.
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Actual Discharge
(cfs)
Total Allowable
Discharge (cfs)
10 -Year Event
0.89
0.1*1.191 0.12
100 -Year Event
1.21
0.3 *1.191 0.36
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AMERICAN STRUCTUREPOINT, INC.
III. PROPOSED DRAINAGE
Once the site is fully redeveloped, runoff from the site will be collected in an on -site storm sewer system. An
overall drainage area map can be found in Appendix F. The stormwater will be conveyed through the on -site
storm sewer system to an underground detention system. The underground detention system will provide
storage during large rain events so the proposed discharge from the site is not greater than the allowable site
discharges found in the City of Carmel Stormwater Technical Standards Manual. The underground detention
system has been sized to accommodate these regulations. The allowable discharge for the site is 0.1 cfs per
acre for the 10 -year storm and 0.3 cfs per acre for the 100 -year storm. The underground detention system has
been sized for these standards, and the calculated discharge can be found in the summary table below.
The calculated conditions show a peak 100 -year stage elevation of 827.71. The City of Carmel Stormwater
Technical Standards Manual also states that the minimum orifice size to be used on site is six inches. Using a
minimum 6 -inch orifice, the model was run again and the "actual discharge" can be found in the summary table
below.
The actual conditions showed a peak 100 -year stage elevation of 826.33. Calculations for the proposed
drainage conditions were produced using HydroCAD Version 9.00 by HydroCAD Software Solutions, LLC,
and can be found in Appendix G.
IV. STORM SEWER DESIGN
The storm sewer system has been designed based on a 10 -year storm event in accordance with the City of
Carmel Stormwater Technical Standards Manual. A storm sewer basin map of the proposed site can be found
in Appendix H, and the design calculations can be found in Appendix I of this report.
V. STORMWATER QUALITY
The City of Carmel Stormwater Technical Standards Manual states that the flow through BMP sizing
calculation is found by determining a CNwq value for the site and using that value for a 1 -inch, 24- hour storm
event. All stormwater runoff from the site will discharge into a stormwater quality treatment unit known as an
AquaSwirl Storm Water Quality Unit. This hydraulic chamber separation method will capture the required
80 percent total suspended solids, along with other floating debris and hydrocarbons, prior to discharging into
the downstream storm system. An AS -6 AquaSwirl model has been selected to treat a maximum flow rate of
1.80 cfs per Table 1 of the City of Indianapolis SQU Selection Guide. This AS -6 SWQU will effectively
provide treatment not only for the first flush, but also for all rainfall events up to and including the 100 -year
storm event. The AS -6 Aquaswirl model is an ideal fit for this development. The design calculations can be
found in Appendix J of this report.
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Calculated Discharge
(cfs)
Total Allowable
Discharge (cfs)
10 -Year Event
0.11
0.1*1.191 0.12
100 -Year Event
0.30
0.3 *1.191 0.36
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AMERICAN STRUCTUREPOINT, INC.
III. PROPOSED DRAINAGE
Once the site is fully redeveloped, runoff from the site will be collected in an on -site storm sewer system. An
overall drainage area map can be found in Appendix F. The stormwater will be conveyed through the on -site
storm sewer system to an underground detention system. The underground detention system will provide
storage during large rain events so the proposed discharge from the site is not greater than the allowable site
discharges found in the City of Carmel Stormwater Technical Standards Manual. The underground detention
system has been sized to accommodate these regulations. The allowable discharge for the site is 0.1 cfs per
acre for the 10 -year storm and 0.3 cfs per acre for the 100 -year storm. The underground detention system has
been sized for these standards, and the calculated discharge can be found in the summary table below.
The calculated conditions show a peak 100 -year stage elevation of 827.71. The City of Carmel Stormwater
Technical Standards Manual also states that the minimum orifice size to be used on site is six inches. Using a
minimum 6 -inch orifice, the model was run again and the "actual discharge" can be found in the summary table
below.
The actual conditions showed a peak 100 -year stage elevation of 826.33. Calculations for the proposed
drainage conditions were produced using HydroCAD Version 9.00 by HydroCAD Software Solutions, LLC,
and can be found in Appendix G.
IV. STORM SEWER DESIGN
The storm sewer system has been designed based on a 10 -year storm event in accordance with the City of
Carmel Stormwater Technical Standards Manual. A storm sewer basin map of the proposed site can be found
in Appendix H, and the design calculations can be found in Appendix I of this report.
V. STORMWATER QUALITY
The City of Carmel Stormwater Technical Standards Manual states that the flow through BMP sizing
calculation is found by determining a CNwq value for the site and using that value for a 1 -inch, 24- hour storm
event. All stormwater runoff from the site will discharge into a stormwater quality treatment unit known as an
AquaSwirl Storm Water Quality Unit. This hydraulic chamber separation method will capture the required
80 percent total suspended solids, along with other floating debris and hydrocarbons, prior to discharging into
the downstream storm system. An AS -6 AquaSwirl model has been selected to treat a maximum flow rate of
1.80 cfs per Table 1 of the City of Indianapolis SQU Selection Guide. This AS -6 SWQU will effectively
provide treatment not only for the first flush, but also for all rainfall events up to and including the 100 -year
storm event. The AS -6 Aquaswirl model is an ideal fit for this development. The design calculations can be
found in Appendix J of this report.
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AMERICAN STRUCTUREPOINT, INC.
VI. SUMMARY AND CONCLUSIONS
The redevelopment of this site will decrease the overall runoff to below that of the existing conditions. The
decrease stems from the addition of underground stormwater detention. Accordingly, we believe the proposed
improvements will not adversely affect this site, the overall development, or the City of Carmel or Hamilton
County.
1N20060188