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50MSP | NORTH CENTRAL
APPENDIX
ENGINEERING REPORT
·
· Engineers and Land Surveyors
851 Bridger Drive, Suite 1, Bozeman, MT 59715 | phone: 406-522-8594
www.seaeng.com
1
North Central Master Site Plan
Street, Water, Sewer, and Site Preliminary Engineering Report
January 26, Master Site Plan Submittal Updated 7-14-21
Prepared for: HomeBase Montana
Prepared by: Stahly Engineering and Associates
Engineer of Record: Cordell D. Pool, PE
Quality Control Reviewer: Zach Lowe, PE
Attachments
· North Central Phased Civil Plan Sheets C1.0 – C1.4 (Existing Conditions through Phase 4)
· North Central Water Use Estimate by Building and Phase
· Hydrant Flow Test
· North Central Stormwater Calculations
Introduction
North Central is an infill redevelopment roughly centered around Bozeman Medical Arts Center
property. The property consists of all of Block 3 (Lots 1-24) and Lots 1-10 of Block 4 of Beall’s Third
Addition to Bozeman, Lots 2 and 3 of Block A, and all of Block B of Tracy’s Third Addition to
Bozeman. The total property size is 5.26 acres. North Central consists of 9 mixed-use buildings
with approximately 940,000 sf of building area. North Central includes the existing One 11 building
but impacts from the existing One 11 building have not been considered in this report, since impacts
were addressed during its recent development. One 11 2.0 is a large addition to this existing One 11
building and its development is included in this evaluation. The complete North Central building
program is provided elsewhere within the Master Site Plan application.
North Central envisions minor upgrades to adjacent public streets, and water, sewer, and storm
drainage systems. The most extensive upgrades to public spaces include streetscape
improvements providing urban streetscapes that are vibrant and welcoming and more subdued
residential streetscapes where adjacent to existing neighborhoods. Urban streetscapes include
“storefront” sidewalks made up of concrete sidewalks and permeable pavers, on-street parking,
furniture, public bike racks, street trees, and pedestrian scale lighting. Additionally, curb bulbs and
mid-block crosswalks are utilized in appropriate locations to emphasize pedestrian travel. Public
storm drainage modifications will improve roadway drainage adjacent to the site.
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The site improvements consist of phased demolition and construction of new buildings, service lines,
franchise utilities, and site open spaces. All on-site parking is located within building garages with
the exception of the surface parking lot serving the One 11 building. The proposed site
improvements will provide inviting pedestrian pathways and open spaces through the site. These
open spaces will also provide convenient locations for trash collection, franchise utilities, and on-site
stormwater mitigation. Proposed buildings will be served by new services installed on the existing
water and sewer network in the adjacent streets. It is anticipated that some buildings will require
new fire hydrants located near Fire Department connections to the building fire suppression systems,
potentially beyond the typical City of Bozeman design standards.
Figure 1 – North Central Master Plan Project Vicinity
Figure 1 illustrates the location of the development as well as proposed structures. Proposed
phasing of the North Central Master Plan is shown on Plan Sheets C1.0 through C1.4 (existing
conditions, and Phase 1 through 4).
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Civil Specifications and Design Standards
The civil specifications for the project will be the Montana Public Works Standard Specifications
(MPWSS) and the City of Bozeman Modifications to MPWSS (COB Mods). Construction plans will
be developed in accordance with the City of Bozeman Design Standards.
Street Improvements
Except for the un-improved section of Villard Street and the alley west of Block 4 the existing streets
appear to be in adequate condition. Some minor street improvements are proposed to support the
North Central Master Plan. Willson Avenue between Beall and Villard is proposed to be widened
from 37’ wide to 39’ wide to better align with the street south of Beall. Beall Street is currently 45’
wide between Willson and Tracy with curb-walks on either side. This plan proposes narrowing Beall
Street to 37’ width to match the street sections to the east and west. The unimproved section of
Villard Street adjacent to Block 4 will be improved to a 37’ wide street to match improved sections of
this street. Tracy Avenue will remain a 29’-30’ wide street with parking only on the west side.
Lamme Street and Grand Avenue will remain at their existing widths (34’ and 37’ respectively).
Streetscape improvements are proposed with respect to the Block Frontage requirements.
Storefront streetscapes where buildings are placed near the street are predominant. The proposed
storefront streetscape consists of a 6’ wide concrete sidewalk and 6’ wide permeable paver
boulevard. Curbed planting beds are proposed around street trees to provide a more appealing
landscape than tree grates. Where pedestrian activity is emphasized, benches, bike racks, and
pedestrian-scale lighting is incorporated into the streetscape. Additionally, mid-block crosswalks are
proposed on Willson and Beall and curb bulbs are proposed on Beall Street between Willson and
Tracy to improve pedestrian mobility around and through the site. Where buildings are setback from
the street, a typical sidewalk and planted boulevard streetscape is proposed.
On-street parking will be maintained as allowed by City code. Parking is not proposed within street
vision triangles, within 20’ of mid-block crossings, or in front of trash or maintenance accesses.
A new storm drain is proposed in Villard to improve drainage of the unimproved and low-slope
portions of this street. A new storm drain is proposed in Tracy to collect storm runoff from Block 3.
Street curb and gutter will be replaced along all building frontages, and additional curb inlets are
proposed to improve street drainage at intersection crosswalks.
The existing unimproved 14’ alley west of Block 4 will be paved and widened to a 16’ paved alley
with new alley approaches.
Water
City water mains exist in Willson Avenue, Tracy Avenue, Beall Street, Grand Avenue, and Lamme
Street. The water mains in Willson Avenue, Tracy Avenue, and Grand Avenue are each 6” cast iron,
the water main in Beall Street is 10” cast iron, and the water main in Lamme Street is 8” ductile iron.
The existing buildings on Block 3 are served by a single water and a single fire service from the
water main in Beall Street. Block 4 has no building services, but landscape irrigation is provided by a
water service from the water main in Willson. The existing buildings in Block A are served by
adjacent connections to the main in Beall. Lot A of Block B is currently a parking lot and contains no
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water service connection, and the existing One 11 building is served by connections to the main in
Lamme. The capacity of the existing water mains in this portion of town has been shown by the
City’s Facility Plan to be adequate to support re-development. North Central, a high-density urban
development, has a very efficient water use and there is significant water use currently occurring on
the site. Proposed buildings would have new services for water, fire protection and sewer. New fire
hydrants are proposed near Fire Department connections to the building fire suppression systems.
Table 1. North Central Estimated Water Use
Total Development Summary
Average Daily Flow
New Flows Introduced Area (sf) # Units gpd/1000 sf Gpd/Unit Gpd
Residential Units 438 141.05 61,780
Office 43,500 30 1,305
Retail 26,600 30 798
Hotel 66,000 100 90 9,000
Restaurant 11,000 500 5,500
Irrigation 3,257
Total New Flows 81,640
Existing Flows Removed Area (sf) # Units gpd/1000 sf Gpd/Unit Gpd
Demolished Structures Data from Meter Readings -9,956
Total Net Increase in Flow from Redevelopment Gpd
new flows introduced minus existing flows removed 71,684
Peaking Factor 4.5
Net New Peak Hour Flow (gpm) 224.0
Table 1 provides a summary of the water use estimates for new development within North Central.
Approximately 12.5% of the impact of new water demands from the development are offset by the
existing water uses removed over the course of the project. A detailed water use estimate by
building and phase is provided at the end of the report.
Average domestic water use estimates were made based on proposed building use and typical City
of Bozeman design values. Office and retail spaces use an estimated 30 gallons per day (gpd) per
1000 sf of floor area. Restaurant spaces use an estimated 500 gpd per 1000 sf of floor area. Hotel
space is estimated to use 90 gpd/unit. The residential units were estimated to use water at a rate of
65 gpd/capita with an assumed density of 2.17 people per unit.
The North Central Master Plan anticipates water use that is lower than typical city design flow
estimates. However, there is not currently an established methodology for estimating water use in
this kind of urban, high-density residential use. High efficiency fixtures and efficient design reduces
the per capita water consumption, and this type of urban development typically does not attract
families which results in a lower water use per unit than is typical in the City. While data has not
been available for the requisite 3 years for consideration, nor are there enough comparable
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developed sites, recent data from the similar Black Olive building indicate a water usage rate of
approximately 50 gallons/day/unit. It is anticipated that water use within North Central will be very
similar to that of Black Olive. Comparing of the City accepted water use estimates to measured
Black Olive meter reading data show the Black Olive water use to be approximately 35% of the City
estimates.
Irrigation water use is very low in response to the urban design. Irrigation lines will provide water to
the trees, planters and open spaces on the site. Drought tolerant plants and a drip irrigation system
are proposed to conserve water. Drip irrigation lines and tree bubblers will be used for planters and
trees. The irrigation system will be “high-efficiency” and use an estimated 1.0 acre-feet per year for
the entire North Central project.
Peak hour flows were estimated based on the average daily flow and a peak hour factor of 4.5.
Total peak hour water demand from the new development within North Central is estimated at 255.1
gpm. Applying the same peaking factors to metered flows of existing buildings on the property, it is
estimated that a peak hour demand of 31.1 gpm from existing structures is being removed from the
site through demolition. The net increase to peak hour demand from the existing site conditions to
proposed development is estimated to be 224.0 gpm.
Planned water and fire service lines are shown on the Civil plan sheets. Buildings 3-1, 3-2, and
Mountain View West will connect to the existing 10” water main in Beall Street. Buildings 3-3, 3-4
and Mountain View East will connect to the existing 6” water main in Tracy Avenue. Buildings 3-5
and 4 will connect to the existing 6” water main in Willson Avenue. The One 11 2.0 building will use
the existing One 11 building’s water service, with appropriate upsizing of the existing meter. The
water service line sizes will be determined by the plumbing fixture counts in each building and the
Uniform Plumbing Code flow rates for each of the fixture counts. The water and fire service lines
have not been determined yet, but they are anticipated to be 4” or 6”. The water and fire service lines
will be designed by a PE and submitted for review as required by the building permit.
As part of the 2017 Water facility plan, a fire flow test was performed on a hydrant on the northwest
corner of Villard St and Tracy Ave adjacent to Block 3, and the test results are included with this
report. The static water pressure is approximately 137 psi. Two adjacent hydrants were opened
simultaneously at their 2.5” diameter nozzle, one flowed at 1,601 gpm and the other at 1,744 gpm for
a total flow of 3,345 gpm. These flows resulted in a 25 psi drop at the residual test hydrant, which
had a residual pressure of 112 psi. This test indicates that reasonable urban fire flows can be met in
this area. Four new fire hydrants are proposed, one at each intersection, to provide improved fire
protection for new buildings. It is anticipated that new hydrants would provide similar fire flows to the
existing hydrant tested.
Sewer
City sewer mains exist in Willson Ave, Tracy Ave, and Lamme Street. The sewer main in Willson Ave
is 10” lined vitrified clay pipe (VCP), the sewer main in Tracy Ave is 8” PVC, and the sewer main in
Lamme Street is 10” PVC. It appears that there are 4 existing sewer services, 2 from Willson Ave
and 2 from Tracy Ave serving the existing buildings in Bock 3. Block A appears to currently be
served by a single connection to the main in Lamme Street. One 11 is served by a connection to
Willson Avenue. The capacity of the sewer mains is not easily identified, and the City is currently
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updating their hydraulic model of these sewer mains. The flow data in this report will allow the City
to make capacity determinations of the existing sewer mains. North Central, a high-density urban
development, has a very efficient water use and low wastewater generation, and there is significant
wastewater generation currently occurring on the site.
Proposed new sewer service connections to the existing sewer mains are shown on the Civil plan
sheets. As currently planned, Buildings 3-1, 3-2, 3-5, 4 and One 11 2.0 will connect to the existing
10” sewer main in Willson Avenue. Buildings 3-3 and 3-4 will connect to the existing 8” sewer main in
Tracy Avenue. The Mountain View Buildings will connect to the existing 10” sewer main in Lamme.
Additionally, to accommodate kitchen facilities, grease interceptors are being provided for restaurant
spaces in Building 3-1 and the Mountain View East building.
North Central wastewater generation is anticipated to be equal to the water use shown in Table 1
less the irrigation use, or approximately 78,500 gallons per day. Approximately 10,000 gpd of
existing sewer flows from structures that will be demolished will be removed from the system, for a
net new wastewater generation of 71,700 gpd. Using a peak hour factor of 4.5, the peak hour flow
discharging to the sewer is estimated to be 245.0 gpm. An estimated 31.1 gpm of peak hour
demand will be removed via demolition, for a net increase of peak hour sewer flows of 213.8 gpm.
The net new sewer flows will be split between the 3 existing sewer mains as described previously
and shown in the Civil plan sheets. Approximately 137.8 gpm will be added to the Willson sewer
main at peak hour, approximately 37.4 gpm will be added to the Tracy sewer main at peak hour, and
approximately 20.9 gpm will be added to the Lamme sewer main at peak hour.
Site Improvements
North Central site improvements consist of phased demolition and construction of new buildings,
services lines, franchise utilities, and site open spaces. All on-site parking is located within building
garages with the exception of the One 11 surface lot. The proposed site improvements will provide
inviting pedestrian pathways and open spaces through the site. These open spaces will also provide
convenient locations for trash collection, franchise utilities, and on-site stormwater mitigation.
Lots
With development the existing lots in North Central will be realigned and/or aggregated so each
building will exist on a single lot. One 11 2.0 is an addition to the existing One 11 building, and the
existing lots on Block B will be aggregated so the combined One 11 building and surface parking lot
will occupy a single lot. The two existing lots on Block A will be realigned around the new Mountain
View buildings. The existing lots on Block 4 will similarly be aggregated into a single lot housing
Building 4, while the lots within Block 3 will be aggregated and realigned into 5 new lots. No
additional street right-of-way is required or proposed. Easements will be required to support
common amenities and infrastructure. It is anticipated that easements will be required for common
access, franchise utilities, and stormwater infrastructure.
Access
Site access is thoughtfully designed to be shared, reducing impacts to the streetscape and on-street
parking. Internal pedestrian alleys provide access for trash collection, franchise utilities, and open
space maintenance. Trash accesses are combined where possible, limiting impacts to on-street
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parking, and facilitating easier collection. On-site parking is located within garages in each building
with the exception of Mountain View West. Buildings 3-4 and 3-5 share a single below grade parking
garage accessed from West Villard Street. Buildings 3-1,3-2, and 3-3 also share a common below
grade garage with access from Tracy Avenue. Building 4 contains 3 levels of parking accessed from
the alley and Villard Street. Mountain View East contains below grade parking accessed from
Lamme. One 11 2.0 has ground level parking accessed from the existing One 11 garage from
Willson, with an exit onto Grand Avenue.
Franchise Utilities
Franchise utility routing (power, communications, and gas) within North Central have been shaped
by historical development. Existing franchise utilities exist in the alley in Block 4, the alley north of
Block 3 and within Beall Street right-of-way. Existing buildings within North Central are mostly
supplied by franchise utilities running within Beall Street. The historical utility location will largely be
maintained with new points of service accommodated. The presence of utilities within Beall Street
may impact the ability to place boulevard street trees along this street.
Planned improvements are to place the existing overhead power and communication lines in the
Block 4 alley and Beall Street underground. Building 4 and One 11 2.0 will be served from the new
underground lines. Buildings 3-1, 3-2, 3-3 and Mountain View buildings will be served from the
existing underground utilities in Beall Street. Buildings 3-4 and 3-5 will be served by new
underground utilities extending from the alley north of Block 3. To the extent practical, utility meters
are proposed along the sides of buildings or in building alcoves, leaving the street frontage and
Beall’s Alley frontages free of utilities.
Site Storm Drainage
Existing site drainage within North Central is by surface drainage onto adjacent streets or by direct
connection of roof drains into storm drain mains in streets. Currently the site is approximately 79%
impervious (building, pavement, or sidewalk) without mitigation. City storm drains exist in portions of
Beall Street, Villard Street and Grand Avenue. This drainage condition has not resulted in any
noticeable deficiencies, so the down-stream stormwater system can be considered adequate.
Proposed North Central street improvements will add new storm drains in Villard and Tracy and curb
inlets at intersections. The service area of the storm drains will not be changed, the added storm
drainage infrastructure will serve to reduce surface flow and its impacts to pedestrian travel.
As currently planned the site improvements will result in 81% impervious area, so relatively little
increase from existing conditions. Site storm water mitigation is based on the redevelopment low
impact design (LID) requirement in the City Design Standards to “infiltrate, evapotranspire, or
capture for reuse the runoff generated from the first 0.5” of rainfall from a 24-hour storm. Additionally,
to maintain capacity within the existing storm drainage infrastructure, the storm water mitigation will
reduce peak flows from larger storm events to below the existing storm runoff flows.
Site stormwater mitigation consists of underground chamber/gravel infiltration systems for building
roof runoff and permeable pavers for added site hardscape areas. These systems are planned to
completely retain storm runoff from the most common storm events (approximately 1” storms,
accounting for 97% of storm events in Bozeman), and larger events will overflow (at a reduced rate)
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to City storm drains. A total of 5 infiltration systems are planned for: Block 3 buildings, Block 4,
Block A buildings, One 11 2.0, and the One 11 surface parking lot. Table 2 shows the summary of
the planned retention and runoff reduction. This table shows the significantly reduced storm water
flows achieved by these LID systems. Detailed stormwater calculations are provided at the end of
this report.
Table 2. North Central Site Stormwater Mitigation
System Retention
Volume
(cf)
% Reduction of Storm Runoff from Existing
0.5” 10-year 25-year 50-year 100-year
Block 3 6200 100% 52% 44% 40% 36%
Block 4 2233 100% 50% 42% 37% 33%
Block A 2985 100% 52% 44% 39% 35%
One 11 2.0 1490 100% 60% 51% 45% 41%
One 11 Parking 1198 100% 88% 73% 64% 56%
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Storm Water Maintenance:
General Information
The proposed storm water conveyance and infiltration facilities will be operated and maintained by
the property manager.
Storm Water Facilities Maintenance Schedule
1. Site Housekeeping. (Continuously as needed)
The main cause of storm water facility damage is poor site housekeeping. Sediment tracked
onto pavement can be washed into storm water appurtenances and damage these facilities.
Trash can clog conveyance structures, potentially causing property damage.
· Keep sidewalk, permeable pavers, and parking areas clean.
· Pick up trash.
· Restore damaged landscaping in order to prevent sediment runoff.
2. Curb, Sidewalk Chase, and Infiltration System Maintenance. (Quarterly)
All storm water conveyance structures can acquire sediment and debris buildup. If this
sediment and debris is not periodically removed, it can cause undesired ponding and
clogging. These conveyance structures need to be inspected and cleaned if required.
· Inspect for sediment or debris in the structures and remove if present.
· Inspect infiltration system through inspection ports for sediment accumulation.
Sediment depth less than 3” is acceptable.
· Check for damage, repair as needed.
3. Curb, Sidewalk Chase, and Infiltration System Maintenance. (Long-term)
If regular housekeeping and maintenance is not performed adequately, sediment and debris
can accumulate in the storm water conveyance structures and infiltration system and clog
them beyond repair.
· If greater than 3” of sediment is present in infiltration system, hire a contractor with a
Jet-Vac chamber cleaning system to remove the sediment from the infiltration system.
· If original system performance can be achieved through maintenance, hire a
contractor to repair and return conveyance structures and infiltration system to the
initial design condition found on City engineering plans.
4. System Monitoring. (Quarterly, except in winter)
The storm water facilities shall be inspected quarterly to quickly identify small issues before
expensive damage can occur. In addition to regular monitoring, the best time to inspect the
performance of storm water facilities is during runoff events.
· Observe system during runoff. Look for ponding on permeable pavers or inlet
structures. This can indicate a clogged paver infiltration and/or clogged conveyance
structure.
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· Open infiltration system inspection ports within 24-hours of a storm event and look for
ponded water in the infiltration system. This can indicate clogged infiltration system.
If clogged hire a contractor with a Jet-Vac chamber cleaning system to remove the
sediment from the infiltration system.
5. Permeable Interlocking Concrete Pavement (PICP) Inspection & Maintenance Guidelines.
Service inspection and maintenance shall include the following activities:
· Winter Maintenance:
o Ensure only joint aggregate stone (typically # 8, #89 or #9 washed chip stone)
is used for traction as needed. Sand should not be used for winter traction.
· Normal Maintenance:
o Inspect surface for ponding after large rain events. If ponding is observed,
identify areas with severe sediment loading and vacuum to remove and
replace with new washed joint aggregate (typically # 8, #89, or # 9 washed
chip stone).
o Note any sediment laden run-off from adjacent areas onto permeable
pavement. If needed, correct with erosion control measures.
· Annual inspection and maintenance shall include the following activities:
o Replenish paver joints with additional aggregate if level is more than ½ in.
below chamfer bottoms.
o Inspect vegetation around PICP perimeter for cover & soil stability,
repair/replant as needed.
o Inspect and repair all paver surface deformations (depressions/settlement)
exceeding 1/2 in.
o Repair paver heights offset by more than 1/4 in. above or below adjacent
units, or offset by more than 1/8” lippage from paver-to-paver.
o Replace cracked paver units impairing surface structural integrity.
o Check drains and outfalls (if existing) for free flow of water. Remove any
obstructions.
o Check observation wells (if existing) to confirm reservoir is draining (based on
size of last rain event).
o Vacuum surface (typically spring), adjust vacuuming schedule per sediment
loading. Once a year sweeping is normal unless excessive silts and fines are
present in joints.
o Test surface infiltration rate using ASTM C1781. If pavement infiltration rate is
< 100 in/hr. employ remedial maintenance procedure utilizing a vacuum
sweeper/method to extract affected clogged joints/voids and replace joint/void
areas with #8, #89 or #9 washed chip aggregates and retest infiltration rate to
confirm reinstated areas exceed 100 in/hr. flow rate. Repeat remedial process
as needed to exceed the 100 in/hr. criteria.
· Additional Normal Maintenance Notes:
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o A dry mechanical or regenerative air type sweeper may be used during dry
periods to remove encrusted sediment, leaves, grass clippings, etc. Vacuum
or sweeper settings may require adjustments to prevent uptake of aggregate
from the paver voids or joints. Leaf blowers or other standard onsite manual
methods that are used for standard pavement maintenance may be employed
to remove this surface debris.
o It is not recommended to utilize a pressure washer to clean joints.
o Remove snow with standard plow/snow blowing equipment.
o Deicing salt may be used on permeable pavers (proper application and
appropriate salt type), but consult property owner or project engineer before
usage. In some regions deicing salt use is restricted. Salt use can affect water
quality and have environmental impact.
North Central Master Plan - Stormwater Calculations
Land Classification C
Rooftops 0.9
Pavement 0.9
Sidewalk 0.9
Permeable Pavers 0.3
Landscape 0.2
Total
Weighted Runoff Coeff. (C )
Design Storm 0.5-Inch 10-Year 25-Year 50-Year 100-Year
Drainage Area (acres) 2.203 2.203 2.203 2.203 2.203
Drainage Area (sf) 95983 95983 95983 95983 95983
Slope (%)2 2 2 2 2
Time of Concentration (min) 5.0 5.0 5.0 5.0 5.0
24 Hour Precipitation Volumes (in) 0.50 1.84 2.16 2.42 2.67
Design Storm 0.5 Inch 10-Year 25-Year 50-Year 100-Year
Intensity at Tc (Figure I-2 pg. 29) (in/hr) NA 3.22 3.83 4.74 5.34
Peak Runoff Rate at Tc (Q = CIA) (cfs) NA 5.61 6.67 8.27 9.31
Runoff Volume (cf) 3166 11650 13676 15322 16905
Design Storm 0.5 Inch 10-Year 25-Year 50-Year 100-Year
Intensity at Tc (Figure I-2 pg. 29) (in/hr) NA 3.22 3.83 4.74 5.34
Peak Runoff Rate at Tc (Q = CIA) (cfs) NA 5.67 6.74 8.35 9.40
Runoff Volume (cf) 3196 11763 13809 15471 17069
Design Storm 0.5 Inch 10-Year 25-Year 50-Year 100-Year
Runoff Volume Increase (cf) 0 113 133 149 164
Retention Volume (cf) 6200 6200 6200 6200 6200
Net Runoff Volume Post Mitigation (cf) 0.00 5563 7609 9271 10869
% Decrease in Runoff from Existing 100.00 52.2 44.4 39.5 35.7
Rain Event Captured (in.)0.97
Land Classification C
Rooftops 0.9
Pavement 0.9
Sidewalk 0.9
Permeable Pavers 0.3
Landscape 0.2
Total
Weighted Runoff Coeff. (C )
Design Storm 0.5-Inch 10-Year 25-Year 50-Year 100-Year
Drainage Area (acres) 0.749 0.749 0.749 0.749 0.749
Drainage Area (sf) 32645 32645 32645 32645 32645
Slope (%)2 2 2 2 2
Time of Concentration (min) 5.0 5.0 5.0 5.0 5.0
24 Hour Precipitation Volumes (in) 0.50 1.84 2.16 2.42 2.67
Design Storm 0.5 Inch 10-Year 25-Year 50-Year 100-Year
Intensity at Tc (Figure I-2 pg. 29) (in/hr) NA 3.22 3.83 4.74 5.34
Peak Runoff Rate at Tc (Q = CIA) (cfs) NA 2.00 2.38 2.95 3.32
Runoff Volume (cf) 1128 4153 4875 5462 6026
Design Storm 0.5 Inch 10-Year 25-Year 50-Year 100-Year
Intensity at Tc (Figure I-2 pg. 29) (in/hr) NA 3.22 3.83 4.74 5.34
Peak Runoff Rate at Tc (Q = CIA) (cfs) NA 2.09 2.48 3.08 3.46
Runoff Volume (cf) 1177 4331 5084 5696 6284
Design Storm 0.5 Inch 10-Year 25-Year 50-Year 100-Year
Runoff Volume Increase (cf) 48 178 209 234 258
Retention Volume (cf) 2233 2233 2233 2233 2233
Net Runoff Volume Post Mitigation (cf) 0.00 2098 2851 3463 4051
% Decrease in Runoff from Existing 100.00 49.5 41.5 36.6 32.8
Rain Event Captured (in.)0.95
0.83
29321
875
825
0
1624
32,645
0.87
0
29,364
0
0
3,281
32,645
0.79
77,204
0
4,274
4,841
9,664
95,983
0.80
Block 3
Existing Area (sf) Post Dev Area (sf)
28,554
7,235
0
14,869
95,983
Design Storm Information
Existing Peak Flow Calculations
Post Dev Peak Flow Calculations
Mitigation Calculations
Site Statistics
Design Storm Information
Existing Peak Flow Calculations
Post Dev Peak Flow Calculations
Mitigation Calculations
Site Statistics
Block 4
Existing Area (sf) Post Dev Area (sf)
45,325
Land Classification C
Rooftops 0.9
Pavement 0.9
Sidewalk 0.9
Permeable Pavers 0.3
Landscape 0.2
Total
Weighted Runoff Coeff. (C )
Design Storm 0.5-Inch 10-Year 25-Year 50-Year 100-Year
Drainage Area (acres) 1.090 1.090 1.090 1.090 1.090
Drainage Area (sf) 47468 47468 47468 47468 47468
Slope (%)2 2 2 2 2
Time of Concentration (min) 5.0 5.0 5.0 5.0 5.0
24 Hour Precipitation Volumes (in) 0.50 1.84 2.16 2.42 2.67
Design Storm 0.5 Inch 10-Year 25-Year 50-Year 100-Year
Intensity at Tc (Figure I-2 pg. 29) (in/hr) NA 3.22 3.83 4.74 5.34
Peak Runoff Rate at Tc (Q = CIA) (cfs) NA 2.54 3.02 3.74 4.21
Runoff Volume (cf) 1431 5265 6181 6925 7641
Design Storm 0.5 Inch 10-Year 25-Year 50-Year 100-Year
Intensity at Tc (Figure I-2 pg. 29) (in/hr) NA 3.22 3.83 4.74 5.34
Peak Runoff Rate at Tc (Q = CIA) (cfs) NA 2.65 3.15 3.90 4.39
Runoff Volume (cf) 1494 5499 6456 7233 7980
Design Storm 0.5 Inch 10-Year 25-Year 50-Year 100-Year
Runoff Volume Increase (cf) 64 234 274 307 339
Retention Volume (cf) 2985 2985 2985 2985 2985
Net Runoff Volume Post Mitigation (cf) 0.00 2514 3471 4248 4995
% Decrease in Runoff from Existing 100.00 52.3 43.9 38.7 34.6
Rain Event Captured (in.)1.00
Land Classification C
Rooftops 0.9
Pavement 0.9
Sidewalk 0.9
Permeable Pavers 0.3
Landscape 0.2
Total
Weighted Runoff Coeff. (C )
Design Storm 0.5-Inch 10-Year 25-Year 50-Year 100-Year
Drainage Area (acres) 0.420 0.420 0.420 0.420 0.420
Drainage Area (sf) 18296 18296 18296 18296 18296
Slope (%)2 2 2 2 2
Time of Concentration (min) 5.0 5.0 5.0 5.0 5.0
24 Hour Precipitation Volumes (in) 0.50 1.84 2.16 2.42 2.67
Design Storm 0.5 Inch 10-Year 25-Year 50-Year 100-Year
Intensity at Tc (Figure I-2 pg. 29) (in/hr) NA 3.22 3.83 4.74 5.34
Peak Runoff Rate at Tc (Q = CIA) (cfs) NA 1.16 1.38 1.71 1.92
Runoff Volume (cf) 653 2401 2819 3158 3484
Design Storm 0.5 Inch 10-Year 25-Year 50-Year 100-Year
Intensity at Tc (Figure I-2 pg. 29) (in/hr) NA 3.22 3.83 4.74 5.34
Peak Runoff Rate at Tc (Q = CIA) (cfs) NA 1.18 1.41 1.74 1.96
Runoff Volume (cf) 668 2457 2884 3231 3565
Design Storm 0.5 Inch 10-Year 25-Year 50-Year 100-Year
Runoff Volume Increase (cf) 15 55 65 73 80
Retention Volume (cf) 1490 1490 1490 1490 1490
Net Runoff Volume Post Mitigation (cf) 0.00 967 1394 1741 2075
% Decrease in Runoff from Existing 100.00 59.7 50.6 44.9 40.5
Rain Event Captured (in.)1.12
1,152
18,296
32634
0
4,358
4,763
5,713
47,46847,468
0.72
16944
0
716
0
0.76
17,144
0
0
Post Dev Peak Flow Calculations
Mitigation Calculations
Existing Peak Flow Calculations
Post Dev Peak Flow Calculations
Mitigation Calculations
Site Statistics
Design Storm Information
Existing Peak Flow Calculations
Block B - One11 2.0
Existing Area (sf) Post Dev Area (sf)
0
0.86
636
18,296
0.88
Site Statistics
Design Storm Information
Block A - Mountainview
Existing Area (sf) Post Dev Area (sf)
21,664
3,540
10,290
0
11,974
Land Classification C
Rooftops 0.9
Pavement 0.9
Sidewalk 0.9
Permeable Pavers 0.3
Landscape 0.2
Total
Weighted Runoff Coeff. (C )
Design Storm 0.5-Inch 10-Year 25-Year 50-Year 100-Year
Drainage Area (acres) 0.252 0.252 0.252 0.252 0.252
Drainage Area (sf) 10974 10974 10974 10974 10974
Slope (%)2 2 2 2 2
Time of Concentration (min) 5.0 5.0 5.0 5.0 5.0
24 Hour Precipitation Volumes (in) 0.50 1.84 2.16 2.42 2.67
Design Storm 0.5 Inch 10-Year 25-Year 50-Year 100-Year
Intensity at Tc (Figure I-2 pg. 29) (in/hr) NA 3.22 3.83 4.74 5.34
Peak Runoff Rate at Tc (Q = CIA) (cfs) NA 0.56 0.66 0.82 0.93
Runoff Volume (cf) 316 1161 1362 1526 1684
Design Storm 0.5 Inch 10-Year 25-Year 50-Year 100-Year
Intensity at Tc (Figure I-2 pg. 29) (in/hr) NA 3.22 3.83 4.74 5.34
Peak Runoff Rate at Tc (Q = CIA) (cfs) NA 0.64 0.76 0.95 1.07
Runoff Volume (cf) 362 1333 1565 1753 1934
Design Storm 0.5 Inch 10-Year 25-Year 50-Year 100-Year
Runoff Volume Increase (cf) 46 172 203 227 250
Retention Volume (cf) 1198 1198 1198 1198 1198
Net Runoff Volume Post Mitigation (cf) 0.00 135 367 555 736
% Decrease in Runoff from Existing 100.00 88.4 73.1 63.6 56.3
Rain Event Captured (in.)1.66
Post Dev Peak Flow Calculations
Mitigation Calculations
10,974 10,974
0.69 0.79
Design Storm Information
Existing Peak Flow Calculations
593 0
0 0
3,297 1692
Site Statistics
Existing Area (sf) Post Dev Area (sf)
2,805 0
4,279 9,282
North Central Master Plan Water Use Estimate
Existing Conditions
Buildings
Medical Arts Building Area (sf)# Units gpd/1000 sf Gpd/Unit Gpd
"Tower" Building Data from Meter Readings 1611
Existing 1 Story Building 196
Medical Arts Building 1773
Total 3581
Mountain View Building Area (sf)# Units gpd/1000 sf Gpd/Unit Gpd
Mountain View Building Data from Meter Readings 3657
Deaconess Building 2718
Total 6375
Existing Conditions Total Water Total (gpd)
Phase 1
Phase 1 Construction
Average Daily Flow
Building 4-1 Area (sf)# Units gpd/1000 sf Gpd/Unit Gpd
Residential Unit 99 141.05 13,964
Retail 6100 30 183
Irrigation 544
Subtotal 14,691
One11 2.0 Area (sf)# Units gpd/1000 sf Gpd/Unit Gpd
Residential Unit 67 141.05 9,450
Retail 2500 30 75
Irrigation 176
Subtotal 9,701
Phase 1 Summary Water Total (gpd)
24392
0
24392
Phase 2
Phase 2 Construction
Average Daily Flow
Building 3-4 Area (sf)# Units gpd/1000 sf Gpd/Unit Gpd
Residential Unit 44 141.05 6,206
Irrigation 369
Subtotal 6,575
Mountain View East Area (sf)# Units gpd/1000 sf Gpd/Unit Gpd
Residential Unit 42 141.05 5,924
Restaurant 5000 500 2,500
Retail 9000 30 270
Office 43500 30 1,305
Irrigation 472
Subtotal 4,547
Phase 2 Demolition
Buildings Average Daily Flow
Existing Structures Area (sf)# Units gpd/1000 sf Gpd/Unit Gpd
Existing 1 Story Building Data from Meter Readings -196
Mountain View Building Data from Meter Readings -3657
Phase 2 Summary Water Total (gpd)
11122
-3854
7268
Phase 3
Phase 3 Construction
Average Daily Flow
Building 3-1 Area (sf)# Units gpd/1000 sf Gpd/Unit Gpd
Residential Unit 30 141.05 4,232
Retail 3000 30 90
Restaurant 6000 500 3,000
Irrigation 195
Subtotal 7,517
Building 3-2 Area (sf)# Units gpd/1000 sf Gpd/Unit Gpd
Residential Unit 40 141.05 5,642
Retail 3000 30 90
Irrigation 289
Subtotal 6,021
Building 3-3 Area (sf)# Units gpd/1000 sf Gpd/Unit Gpd
Residential Unit 46 141.05 6,488
Retail 3000 30 90
Irrigation 391
Subtotal 6,969
Mountain View West Area (sf)# Units gpd/1000 sf Gpd/Unit Gpd
Retail 0 30 0
Hotel 66000 100 90 9,000
Irrigation 319
Subtotal 9,319
Phase 3 Demolition
Buildings Average Daily Flow
Existing Structures Area (sf)# Units gpd/1000 sf Gpd/Unit Gpd
Medical Arts Building Data from Meter Readings -1773
Deaconess Building Data from Meter Readings -2718
Phase 3 Summary Water Total (gpd)
29826
-4491
25335
Phase 4
Phase 4 Construction
Average Daily Flow
Building 3-5 Area (sf)# Units gpd/1000 sf Gpd/Unit Gpd
Residential Unit 70 141.05 9,874
Irrigation 502
Subtotal 10,376
Phase 4 Demolition
Average Daily Flow
Existing Structures Area (sf)# Units gpd/1000 sf Gpd/Unit Gpd
"Tower" Building Data from Meter Readings -1611
Phase 4 Summary Water Total (gpd)
10376
-1611
8764
New Flows Introduced Area (sf)# Units gpd/1000 sf Gpd/Unit Gpd
Residential Units 438 141.05 61,780
Office 43,500 30 1,305
Retail 26,600 30 798
Hotel 66,000 100 90 9,000
Restaurant 11,000 500 5,500
Irrigation 3,257
Total New Flows 81,640
Existing Flows Removed Area (sf)# Units gpd/1000 sf Gpd/Unit Gpd
Demolished Structures Data from Meter Readings -9,956
Total Net Increase in Flow from Redevelopment Gpd
71,684
4.5
224.0
Peaking Factor
Peak Hour Flow (gpm)
new flows introduced minus existing flows removed
Construction
Demolition
Phase Total Net Change
Construction
Demolition
Phase Total Net Change
Total Development Summary
Average Daily Flow
Construction
Demolition
Phase Total Net Change
Construction
Demolition
Phase Total Net Change
Average Daily Flow
9956.20