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WOOLPERT
Drainage Report
THOMSON CONSUMER
ELECTRONICS PARKING LOT
ANNEX
Hines Interest, L.P.
Carmel, Indiana
June 2000
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1 Drainage Report
1 THOMSON CONSUMER
ELECTRONICS PARKING LOT
I ANNEX
IHines Interest, L.P.
Carmel, Indiana
1 June 2000
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TABLE OF CONTENTS
DRAINAGE SUMMARY & MAPS SECTION 1
EXISTING CONDITIONS ANALYSIS SECTION 2
DEVELOPED CONDITIONS ANALYSIS SECTION 3
STORM SEWER CALCULATIONS SECTION 4
Woolpert
June 2000
Thomson Consumer Electronics Parking Lot Annex
Hines Interest, L.P.
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DRAINAGE REPORT
Existing Conditions
The existing 4.8 -acre site is located within the overall 13.9 -acre tract owned by the Pilgrim Lutheran
Church. The site is located on the west side of US 31 and north of Interstate 465 in the US 31 Overlay
Zone in Carmel, Indiana. The parent tract contains the church, a parsonage, which is being used as the
church offices, a detention pond, and open grassy fields.
Presently, the site is an open field with . grass covering. This site currently sheet drains south to existing
drainage inlets located in the outlet storm sewer of the existing detention pond. The detention basin
accepts runoff from a portion of the church parcel, the parsonage /office site, and approximately 6 acres of
the US 31 right -of -way. The existing flow rates for the pond and the area draining directly to the storm
sewer have been analyzed based on the current conditions. The proposed site was analyzed at the 10 year
existing conditions with the 100 year existing conditions for the remainder of the contributing watershed
areas for the 24 hour rainfall.
According to the Flood Boundary and Floodway Map, Community Panel Number 180081- 0012C; for the
City of Carmel, Hamilton County, Indiana, dated May 19; .1981, this site lies within a Zone C which is
determined to be outside the 100 -year floodplain.
Proposed Conditions
The proposed site improvements include construction of a 1.9 -acre asphalt parking lot, with entrance
drives, sidewalks, landscaping, and storm sewers. The storm water runoff from the site will be collected
by inlets and storm sewers and routed through the existing detention basin. The detention basin and
outlet provide adequate storage capacity and maintain the existing flowrate as indicated in the table
below.
Woolpert
June 2000
Thomson Consumer Electronics Parking Lot Annex
Hines Interest, L.P.
Existing
Proposed
Pond Release Rate
8.53 cfs
8.80 cfs
Total Discharge
17.92 cfs
13.32 cfs
Woolpert
June 2000
Thomson Consumer Electronics Parking Lot Annex
Hines Interest, L.P.
The storm sewer network has been designed using the Rational Method for a ten year rainfall event in the
developed condition with the pipes flowing full. The storm sewer network will outlet to an existing wet
detention basin at the southeast corner of the site.
Conclusion
The proposed Thomson Consumer Electronics Parking Lot Annex site has been designed in accordance
with the requirements for Carmel, Indiana, with regard to storm water detention. Since the total release
rate has been reduced to 13.32 cfs from the existing 17.92 cfs by routing more of the site area through the
existing detention basin, no adverse impacts are anticipated from this development.
Woolpert
June 2000
Thomson Consumer Electronics Parking Lot Annex
Hines Interest, L.P.