HomeMy WebLinkAbout18 - Design Report - Cannery District Ph 3 - Stormwater
Engineer’s Stormwater Report
Cannery District PUD
Phase 3 Update
December 21, 2018
For Submittal to:
City of Bozeman Engineering Department
20 East Olive
Bozeman, MT 59715
Prepared by:
Stahly Engineering and Associates
851 Bridger Drive, Suite 1
Bozeman, MT 59715
(406) 522-9526
Stormwater Plan 1 12/20/2018
Cannery District Phase 3 Stormwater Report
Contents
General Information
Existing Conditions and General Design Criteria
Storm Drainage Plan Description
Estimation of Retention Volume
Retention Facilities
Curb and Gutter Capacity
Inlet Capacity
Conveyance Capacities
Facilities Maintenance
Figures and Tables
Figure 1. Vicinity Map
Figure 2. Storm Water Plan
Table 1. Cumulative Retention Volume Needed by Phase
Table 2. Cumulative Retention Capacity by Phase
Table 3 Curb and Gutter Capacity Calculations
Table 4 Inlet Drainage Basin and Pipe Capacity Calculations
Appendices
Cannery District Covenants
Stormwater Plan 2 12/20/2018
General Information
The Cannery District is a multi-phase development located on the north side of
East Oak Street and Rouse Avenue, north of the Gallatin County Fairgrounds.
The existing property consists of several parcels of land within the City and
County, with 5.24 acres within the City and 6.98 acres in the county.
The development consists of four phases. The first phase, which was completed
in 2016, consisted of remodeling four existing buildings originally constructed as
part of the original pea canning operation in 1917. Phases 2, 3 and 4 include the
construction of six new buildings on the Cannery District property. Phases 2 and
4 improvements were completed in 2018, leaving only the proposed Phase 3
improvements unconstructed.
In Phases 2 and 4, four new buildings were constructed in the Cannery District;
this report focuses on the last phase of development within the Cannery District
PUD—Phase 3. Phase 3 is 3.22 acres and includes the construction of two new
buildings (Buildings ‘L’ and ‘M’), as well as associated site and utility
improvements.
The developer’s contact information is:
Cannery District Partners, LLC
1006 W Main Street
Bozeman, MT 95715
Figure 1: Vicinity Map
Stormwater Plan 3 12/20/2018
Existing Conditions and General Design Criteria
The site’s existing conditions consist of four recently remodeled buildings within
the previously completed Phase 1 area. The majority of the land was
undeveloped, but has since been improved with buildings, hardscape, landscape
and utilities. The site’s topography allows for drainage to the northwest corner.
During Phase 1, a storm water retention pond was constructed in this location,
and a network of storm pipes and bioswales were constructed which provides the
majority of the storm drainage infrastructure needed for future phases. Near the
northeast corner of the lot, an existing stormwater detention pond is currently in
use to serve the Northside PUD which consists of four buildings on 3.024 ac of
land located at the corner of Oak and Rouse.
In accordance with the City of Bozeman Design Standards and Specifications
Policy (COB Standards) an engineering analysis was conducted evaluating all
four phases within the Cannery District property.
The proposed design includes storm sewers that have been sized to convey the
25-year storm event with no surcharging. The storm sewers drain towards the
northwest corner of the lot. Due to the presence of Interstate 90 on the northern
boundary of the Cannery District property the storm sewers end in a retention
pond sized to handle a 10-year, 2-hour event per COB Standards. Furthermore,
storm water bioswales have been used throughout the site to further reduce
surface runoff and enhance stormwater infiltration.
Storm Drainage Plan
Storm drainage improvements for the Cannery District will be constructed in
accordance with City of Bozeman Requirements. Phase 1 storm drainage
improvements previously constructed provide the “backbone” drainage
infrastructure for the remaining phases. Therefore a Master Grading Plan was
been prepared for the Cannery District, to determine future phase’s drainage
requirements.
The overall storm drainage plan for the Cannery District is depicted on Figure 1
at the end of this report. Overall drainage direction on the proposed
development is indicated by arrows showing the proposed drainage patterns and
inlet locations.
During Phase 3, the existing storm retention pond located to the north of the
Northside PUD will be replaced by a stormwater collection system that will direct
this water to the existing Cannery District retention basin, through an extended
main (Storm Main Pipe ‘C’).
Stormwater Plan 4 12/20/2018
Estimation of Retention Volume
Runoff estimates were obtained for each phase using a 10-year 2-hour design
storm. The Bozeman IDF curves show a rainfall intensity of 0.41 in/hour for the
10-year 2-hour design storm. Using a runoff coefficient of 0.8 (Commercial
Downtown), and the accumulative area by phase, it was determined that a 10-
year, 2-hour retention volume of 38,859 cf will be required.
Table 1 – Cumulative Retention Volume Needed by Phase
10-year 2-hour event
Phase 1 Phase 2 Phase 3 Phase 4
weighted C Factor C 0.8 0.8 0.8 0.8
Intensity I in/hr 0.41 0.41 0.41 0.41
Area A acres 5.34 8.30 14.63 16.45
Runoff Q cfs 1.75 2.72 4.80 5.40
Retention Volume V cf 12,614 19,594 34,557 38,859
NOTE: Phase 3 includes Northside PUD runoff
Retention Facilities
The main retention basin is located on the northwest (down gradient) corner of
the site, bordering the interstate right-of-way. It has slopes of 4:1, a maximum
water depth of 2 ft, and is vegetated with grass. The retention basin was
constructed in Phase 1 with a volume of 32,736 cubic feet.
To supplement the required retention volume, and achieve Low Impact Design
(LID), bioswales have been installed in each phase of development within the
parking landscaped parking islands. Bioswales not only add retention volume,
but slow the peak flows and increase efficiency of stormwater infiltration.
The bioswales have a 12” depth below the overflow outlet, and consist of 24” of
bioswale media (mixture of sand, topsoil, and compost) topped with vegetation
per the landscape plans. Bioswale capacities were calculated using a 0.35 void
ratio. In Phases 1 and 2, nearly 16,000 sf of bioswales were constructed within
the landscaped parking islands of the Cannery District, adding an additional
11,126 cf of storage. In Phase 3, another 3,076 sf of bioswales will be
constructed which will increase the retention capacity another 2,153 cf.
The volume provided by each phase of construction shown in Table 2, totaling
46,060 cf of retention storage, and exceeding the required storage amount for
the calculated 10-year, 2-hour storm event by over 7,200 cf:
Stormwater Plan 5 12/20/2018
Table 2 – Cumulative Retention Capacity by Phase
Phase Volume (cf) Notes
1 40,054 Initial retention basin/ bioswales
2 43,862 Initial retention basin/ added bioswales
3 46,060 Initial retention basin/added bioswales
4 46,060 Initial retention basin/added bioswales
Curb and Gutter Capacity
Storm runoff will be collected in street and parking lot curb and gutters. The
hydraulic capacity of the curb and gutter was analyzed to determine if the curb
would be overtopped in a 25-year event. The maximum 25-year event for any of
the new curb inlet basins produces approximately 3.74 cfs of runoff. The
capacity of the curb at the lowest designed slope of 0.5% is 5.03 cfs at a depth of
0.15 feet below the top of the curb. Therefore, curb capacities in the
development are adequate to carry the 25-year event.
Table 3 – Curb and Gutter Capacity Calculations
Right-side slope X:1 0.05
Left-side slope X:1 33.00
Channel bottom width (ft) 0
Flow Depth (ft) 0.350
Flow Area (ft^2) 2.024
Wetted Perimeter (ft) 11.906
Width 0.035
Hydraulic Radius (ft) 0.170
Manning's Roughness 0.013
Slope (ft/ft) 0.005
Average Velocity (ft/sec) 2.49
Flow (ft^3/sec) 5.03
Inlet and Area Drain Capacity
The curb inlets and area drains on the roadways in the development were
analyzed to ensure they have capacity to accept flows conveyed to them without
reaching a point 0.15 feet from the top of the curb. The COB approved Neenah
Foundry R-3067-L inlet structure has a capacity of 5.98 cfs at 0.35 feet of head
(0.15 below top of curb). The COB approved Neenah Foundry R-2533 area
drain has a capacity of 3.2 cfs at 0.45 feet of head (0.15 feet below top of lowest
adjacent curb). These capacities will convey the estimated flows.
Pipes
A series of 15”, 18”, 24” mains are proposed to be installed in the Phase 3
improvements as shown in Figure 2. Anticipated flows through the mains are
summarized in Table 4 and show that the capacity of the Cannery District storm
Stormwater Plan 6 12/20/2018
mains remains near 75% during peak runoff. Calculations predict surcharging of
the 15” outlet pipe coming from the Northwest PUD development; however the
Cannery District storm mains are able to accommodate the full-flow from the
Northwest PUD’s 15” outlet—as well as the anticipated runoff from the Cannery
District development. Pipe 1B calculations indicate the 30” main will be running
at 84% capacity at peak flows; however the infiltration and retention from the
bioswales throughout the site have not been included in the calculations of the
runoff—thereby inflating the flows that should actually be seen within the
collection network.
Facilities Maintenance
The proposed storm drainage facilities will be operated and maintained by the
property owners’ association (POA), as required by the existing Cannery District
Covenants. The POA is responsible for quarterly maintenance of all storm water
facilities. The maintenance includes, but is not limited to, visual inspection and
removal of sediment from curbs, inlets, retention basins, and outlet structures as
well as any necessary repairs to the facilities. Relevant portions of the Cannery
District’s covenants have been included in the appendix of this report which
outline the prescribed maintenance activities.
Table 4Inlet Drainage Basin and Pipe Capacity Calculations (All Phases)Inlet Drainage BasinInlet Basin 124567891011121314151617181920Land Use M-I M-I M-I M-I M-I M-I M-I M-I M-I M-I M-I M-I M-I M-I M-I M-I M-I M-I M-IDrainage Area (acres) 0.65 0.34 0.67 0.40 1.32 1.00 0.94 0.53 0.43 0.91 0.58 0.55 0.36 1.13 0.24 0.53 0.18 0.50 3.06Slope (%) 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5Runoff Coefficients 0.8 0.8 0.8 0.8 0.8 0.8 0.8 0.8 0.8 0.8 0.8 0.8 0.8 0.8 0.8 0.8 0.8 0.8 0.8Frequency Adjustment Factor, Cf 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1Basin Length (ft) 205 148 254 135 246 255 181 178 231 255 190 153 148 222 180 125 110 160 365Time of Concentration (min) 5.1 4.4 5.7 4.2 5.6 5.7 4.8 4.8 5.5 5.7 5.0 4.4 4.4 5.4 4.8 4.0 3.8 4.5 6.9Peak Flow CalculationsDesign Storm 25yr 25yr 25yr 25yr 25yr 25yr 25yr 25yr 25yr 25yr 25yr 25yr 25yr 25yr 25yr 25yr 25yr 25yr 25yrIntensity at Tc (Figure I-2 pg. 29) (in/hr) 3.76 4.17 3.51 4.29 3.54 3.50 3.91 3.93 3.62 3.50 3.85 4.13 4.17 3.66 3.92 4.40 4.58 4.07 3.12Peak Runoff Rate at Tc (Q = CIA) (cfs)1.951.131.881.373.74 2.802.94 1.671.24 2.551.791.821.203.31 0.751.870.661.637.65Storm Drain Pipe A CapacityManhole NumberPipe End ST1A ST2A ST3A ST4A ST5A ST6A ST7A*Rim Elev 4747.03 4749.51 4749.88 4749.25 4750.39 4750.95 4750.13*Invert 14742.02 4742.74 4745.22 4746.32 4745.67 4745.98 4747.264747.38 *Red numbers are as-built*Invert 2 4745.97 4746.73Pipe Number1A 2A 3A 4A 5A 6A 7APipe Size (in) 24.00 24.00 15.00 24.00 24.00 15.00 15.00Pipe Length 47.00 175.14 68.36 122.76 71.94 108.88 30.84Manning's "n" (PVC) 0.013 0.013 0.013 0.013 0.013 0.013 0.013Area (ft2)3.14 3.14 1.23 3.14 3.14 1.23 1.23Wetted Perimeter (ft) 6.28 6.28 3.93 6.28 6.28 3.93 3.93Hydraulic Radius (ft) 0.50 0.50 0.31 0.50 0.50 0.31 0.31Slope (ft/ft)0.0153 0.0142 0.0050 0.0037 0.0043 0.00480.0040Full Flow Capacity (cfs) 28.06 27.02 4.58 13.74 14.87 4.49 4.10Velocity (ft/sec) 8.93 8.60 3.73 4.37 4.73 3.66 3.34Contributing Inlet Basin NONE 7 2 5 NONE NONE 8Contributing Pipes 2A 3A NONE 5A 6A 7A NONE4AActual Pipe Flow (cfs) 8.25 8.25 1.13 4.31 2.94 2.94 2.94% Capacity 29% 31% 25% 31% 20% 66% 72%Storm Drain Pipe B CapacityManhole NumberPipe End ST1B ST2B ST3B ST4B ST5B ST6B ST7B ST8B ST9B*Rim Elev 4748.23 4748.00 4748.22 4749.65 4749.30 4749.81 4749.81 4750.17 4751.20*Invert4742.16 4743.16 4744.92 4743.32 4744.104744.944745.17 4746.044746.78 4748.06*Invert 2 4744.41 4743.82 4744.85 4745.67 4747.03*Invert 34745.92Pipe Number1B 2B 3B 4B 5B 6B 7B 8B 9BPipe Size (in) 30.00 15.00 30.00 24.00 15.00 24.00 15.00 18.00 15.00Pipe Length 198.17 51.01 31.83 69.66 18.39 248.42 25.00 103.45 75.00Manning's "n" (PVC) 0.013 0.013 0.013 0.013 0.013 0.013 0.013 0.013 0.013Area (ft2)4.91 1.23 4.91 3.14 1.23 3.14 1.23 1.77 1.23Wetted Perimeter (ft) 7.85 3.93 7.85 6.28 3.93 6.28 3.93 4.71 3.93Hydraulic Radius (ft) 0.63 0.31 0.63 0.50 0.31 0.50 0.31 0.38 0.31Slope (ft/ft)0.0050 0.0100 0.0050 0.00400.00500.0043 0.00500.0108 0.0137Full Flow Capacity (cfs) 29.20 6.48 29.08 14.35 4.58 14.91 4.58 10.92 7.58Velocity (ft/sec) 5.95 5.28 5.92 4.57 3.73 4.75 3.73 6.18 6.18Contributing Inlet Basin NONE 9 11 12 17 13 10 14 15Contributing Pipes 2B NONE 4B 5B NONE 7B NONE 9B NONE3B 1C 6B 8BActual Pipe Flow (cfs) 24.44 1.67 22.77 11.22 1.87 7.57 1.24 4.51 3.31% Capacity 84% 26% 78% 78% 41% 51% 27% 41% 44%Storm Drain Pipe C CapacityManhole NumberST3B ST1C ST2C ST3C ST4C End Pipe(EXISTING)Rim Elev 4749.23 4750.40 4751.42Invert 4743.82 4744.84 4746.01 4747.54 4747.47 4747.82 Proposed Phase 3 PipesInvert 2 4746.51 4747.72Invert 3 4746.76Pipe Number1C 2C 3C 4C 5CPipe Size (in) 24 24 15 18 15Pipe Length 145.59 167.98 110.56 137.31 23.99Manning's "n" (PVC) 0.013 0.013 0.013 0.013 0.013Area (ft2)3.14 3.14 1.23 1.77 1.23Wetted Perimeter (ft) 6.28 6.28 3.93 4.71 3.93Hydraulic Radius (ft) 0.50 0.50 0.31 0.38 0.31Slope (ft/ft) 0.0070 0.0070 0.0070 0.0070 0.0040Full Flow Capacity (cfs) 18.98 18.98 5.42 8.81 4.10Velocity (ft/sec) 6.04 6.04 4.42 4.99 3.34Contributing Inlet Basin 16 18 17 19 20Contributing Pipes 2C 3C NONE 5C NONE4CActual Pipe Flow (cfs) 9.00 8.25 1.87 5.72 7.65% Capacity 47% 43% 34% 65% 187%
Figure 2
Stormwater Site Plan
SDSDSD
SD SD SD
SDSD
SD SD SD SD SDSDSDSD SDSDSD
SD SDSDSDSD SDSDSDSD SD SDSDSDSD BASIN 10.65 acBASIN 20.34 acBASIN 40.67 ac BASIN 61.32 acBASIN 71.0 acBASIN 50.40 acBASIN 80.94 acBASIN 100.43 acBASIN 151.13 acBASIN 140.36 acBASIN 130.55 acBASIN 120.58 acBASIN 90.53 acBASIN 110.91 acBASIN 160.24 acBASIN 180.18 acBASIN 170.53 acBASIN 203.06 acBASIN 190.50 acEXISTING PHASE 2STORM IMPROVEMENTSEXISTINGPHASE 1 STORMINPROVEMENTSEXISTING PHASE 1RETENTION PONDVOLUME 32,736 CFEXISTING PHASE 2STORM IMPROVEMENTSPROPOSED PHASE 3 STORMIMPROVEMENTS (DASHED)EXISTING NORTH SIDEPUD STORM MAINS THATCONNECT TO CANNERYDISTRICT SYSTEM INPHASE 3PIPE 1APIPE 2APIPE 4APIPE 3APIPE 5APIPE 7AST1AST2AST3AST4AST5AST6AST7AST4BST5BST6BST7BST8BST9BPIPE 9BPIPE 8BPIPE 7BPIPE 6BPIPE 5BPIPE 4BPIPE 1BST3CPIPE 1CPIPE 2CPIPE 4CST2BPIPE 2BPIPE 3CPIPE 3BST1BPIPE 5CST3BST1CST2CST4CPIPE 6ACANNERY DISTRICT PHASE 3 EXTENTSIN FEETPROFESSIONALENGINEERS &SURVEYORSCANNERY DISTRICTPHASE 3 STAHLYENGINEERING& ASSOCIATESCANNERY DISTRICTPARTNERS, LLCSTORM WATERPLANFIGURE 2
Appendix
reasonabletime from the commencement of such work.Delays in commencement of
constructionmay be grantedforgood causeatthesolediscretionoftheAssociation.
(d)Repairs;Replacements.Allrepairs,alterations,replacementsor additionstoImprovements
shallbe at leastequal to the originalwork in classand quality.The adequacy of such
repairsshallbe measured by the same standardsrequiredforthe originalconstruction.
Maintenancework shallbe incompliancewiththeDesign Guidelinesand,dependingupon
thescope of work,may be subjectto priorreview and approvalof the Cannery District
Review Committee.
(e)Enforcement;Remedies.Ifan Owner failsto performproperlysuch Owner's maintenance
responsibilities,the Associationmay perform them and assessallcostsincurredby the
AssociationagainsttheLot and theOwner.However,exceptwhere entryisrequireddue to
an emergency situation,the AssociationshallaffordtheOwner reasonablenoticeand an
opportunityto curethe problem priorto entry.The noticeshallsetforthwith reasonable
particularitythe maintenance,repairsorreplacementsdeemed necessary.The Owner shall
have 10 days withinwhich tocomplete such maintenance,repairsor replacements.Ifthe
maintenance,repairsor replacementsarenotreasonablycapableof completionwithinthe
10-dayperiod,the Owner shallcommence such work promptly and diligentlyproceedto
completeitwithina reasonabletime.Ifthe Owner does not comply withtheprovisions
hereof,theAssociationshallhave the rightand power to enterontotheLot and perform
such maintenance,repairsorreplacementswithoutany liabilitytoany Personfordamages
forwrongful entry,trespassor otherwise.The Owner of the Lot on which the work is
performedshallbe liable(jointlyand severally,ifmore thanone)forthecostof suchwork
and shallpromptlyreimbursethe Associationforsuch cost,togetherwith interestatthe
same rateas providedfordelinquentassessments,costsand expensesof collection,court
costs,and reasonableattorney'sfees(collectively"charges").The chargesshallalsobe a
continuinglienagainstthe Lot on which thework was performed.Ifthe Owner failsto
reimbursetheAssociationwithin30 days afterreceiptof a statementforsuch work from
the Association,the Associationmay record a notice of lien againstthe Lot.The
Associationmay foreclosethe lienin the same manner as alien forAssessments,and it
shallbe entitledto recover,in additionto the charges,allcostsand expenses of lien
enforcement,includingcourtcostsand reasonableattorney'sfees.
6.3 Noxious Weeds.The controlof noxiousweeds by theAssociationon thoseareasforwhich the
Associationisresponsibleand thecontrolofnoxiousweeds by each Owner on itsrespectiveLot
shallbe assetforthand specifiedundertheMontana Noxious Weed ControlAct (Montana Code
AnnotatedSections7-22-2101through7-22-2153)and therulesand regulationsof theGallatin
County Weed ControlDistrict.The Associationisresponsibleforcontrolof stateand county
declarednoxious weeds in and on the Common Open Space Lots.Each Owner shallbe
responsibleforthe controlof the stateand county declarednoxious weeds on itsLot.Both
unimproved and improved Lotsshallbe managed fornoxiousweeds.Ifan Owner failsto control
the noxious weeds after10 days noticefrom the Association(givenin accordancewith the
provisionsof Subsection6.2(e)above),the Associationmay cause the noxious weeds to be
controlled,and the Associationshallhave the enforcementauthorityand remediesprovidedin
Subsection6.2(e)ofthisDeclaration.
6.4 Storm Water Maintenance Plan.
(a)GeneralInformation.The Cannery DistrictutilizesLow Impact Development ("LID")to
mitigatestormwaterimpacts.The stormwaterfacilitiesconsistofcurband gutter,drainage
swales,bio-retentionareas(bio-swales),conveyancepiping,and a finalretentionbasin.The
systemisdesignedtoaccommodate allstormwaterfrom theProperty.A document entitled
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Storm Water Management Plan and Record Drawings ison fileatthe City of Bozeman,
EngineeringDepartment.
The principalstormwater conveyanceand treatmentfacilitiesarelocatedon theCommon
Open Space Lots,and are owned by Association.Privatelyowned LID storm water
facilitiesservingindividualLot development are encouraged and privatefacilitiesare
allowedtoconnecttotheAssociationfacilitiesthroughtheCommon Open Space Lots.
The AssociationisresponsibleformaintainingstormwaterfacilitiesontheCommon Open
Space Lotsexceptforprivateundergroundservicelines,which aretobe maintainedby the
Lot Owner.Allstorm waterfacilitieslocatedon privatelyowned Lotsshallbe maintained
by theLot Owner inaccordancewiththeapplicablemaintenancescheduleprovidedinthis
Paragraph6.4(b).
The storm water facilitiesare designed to operate without excessivemaintenance.
However,likeallinfrastructure,periodicmaintenance willprevent costlyrepairand
replacement.The maintenanceplan setforthin thisSection6.4 has been preparedin
accordancewith City of Bozeman guidelines.Over time,recommended maintenance
guidelinesmay evolve.PleasecontacttheCityof Bozeman Storm Water Divisionifany
questionsarise.
(b)Storm WaterFacilitiesMaintenanceSchedule.
(i)SiteHousekeeping.Sitehousekeepingisto be conductedcontinuouslyas needed.
The main causeof storm waterfacilitydamage ispoor sitehousekeeping.Sediment
trackedonto pavement can be washed intostorm water bio-retentionbasinsand
conveyance piping and damage these facilities.Trash can clog pipes and inlet
structurescausingpropertydamage.Sitehousekeepingconsistsofthefollowing:
*Keep sidewalkand pavement areasclean
*Pickup trash
*Restoredamaged landscapinginordertopreventsedimentrunoff
(ii)System Monitoring.System monitoringis to be conducted quarterly,except in
winter.The storm water facilitiesshallbe inspectedquarterlyto quicklyidentify
smallissuesbeforeexpensivedamage can occur.In additionto regularmonitoring,
thebesttime to inspectthe performanceof storm water facilitiesisduringrunoff
events.System monitoringconsistsofthefollowing:
*Observe system duringrunoff.Look forponding outsideofretentionareas.This
can indicatea cloggedinletorpipe.
*Inspectbio-retentionand retentionbasins
*Inspectinlets,manholes and pipes
(iii)Bio-retentionand RetentionBasin Maintenance.Bio-retentionand retentionbasin
maintenanceisto be conductedquarterly.The bio-retentionand retentionbasinsare
designedto provide long-term,sustainabletreatmentof storm water.With poor
housekeeping,however,sedimentcan clog thesefacilitiesand reduce infiltration
capacity.Proper and timelycleaningof incidentalsediment in these basinscan
preventthesefacilitiesfrom beingdamaged.The bio-retentionand retentionbasins
are intended to be vegetated,since the vegetationprovides microbiological
communitiesthatcan treatcommon pollutantsin stormwater.Unhealthyvegetation
can diminishthe performanceof thesebasins.The landscapingof thebio-retention
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basinsshallfollowtypicallandscapemaintenanceguidelines.The vegetationon the
bottom of the retentionbasinshould not be regularlymowed,sincemowing can
cause plant debristo build up in the basin.Bio-retentionand retentionbasin
maintenanceconsistsofthefollowing:
*Remove sediment,trash,and debris
*Inspectforhealthyvegetation
*Inspectforuniformpondingand waterdisappearsin3 days
(iv)Bio-retentionand RetentionBasin Maintenance.Bio-retentionand retentionbasin
maintenance is to be conducted annually.The vegetationshould be maintained
annuallytoreduceplantdebrisbuild-up.The retentionbasinvegetationshouldbe cut
to a heightof6"inthefallwiththeclippingsremoved from thebasin.Bio-retention
and retentionbasinmaintenanceconsistsofthefollowing:
*Remove dead plantmaterialsfrom bio-retentionbasins.
*Cut retentionbasinvegetationand remove clippings.
(v)Bio-retentionand RetentionBasinMaintenance.Thismaintenanceistobe conducted
long-termifand when necessary.Ifregularhousekeepingand maintenanceisnot
performedadequately,sedimentand debriscan accumulateinthebasinand reduce
the requiredstoragecapacity.Ifthisoccursthe basinsshould be excavatedback
down to originalplan grade.Long-term bio-retentionand retentionbasin
maintenanceconsistsofthefollowing:
*Hire a contractortoinspectand returnbasinconditionto initialdesignfound on
Cityengineeringplans.
*Dredge basinifsedimentbuild-upisgreaterthan6"
(vi)Inlets.Manholes,and PipingMaintenance.Inlets,manholes,and pipingmaintenance
isto be conductedquarterly.All storm water inletsand manholes have a sump to
capture sediment.If this sediment is not periodicallyremoved it can wash
downstream and clog infiltrationfacilities.The sump istypicallyvisiblefrom the
surfacethroughtheinletgrate.Inlets,manholes,and pipingmaintenanceconsistsof
thefollowing:
*Remove visiblesedimentfrom sump.
*Inspectpipeinletsand outletsforsedimentinpipe,and remove ifpresent.
(vii)Inlets,Manholes,and PipingMaintenance.Thismaintenanceistobe conductedlong-
term if and when necessary.If regularhousekeeping and maintenance is not
performed adequately,sediment and debriscan accumulate in the storm water
conveyancepiping,and pipesmay become clogged.Long-term inlets,manholes,and
pipingmaintenanceconsistsofthefollowing:
*Hirea contractortocleanpipesand remove allsedimentfrom manhole sumps.
SECTION 7 COMMON PROPERTY
7.1 Descriptionof Common Property Declarantintendsto convey to the Associationthe tracts
delineatedas the "Common Open Space Lots"on the Final Plat of the Cannery District
subdivision,togetherwith theImprovements locatedthereon.Upon Declarant'sconveyance of
such propertytotheAssociation,suchpropertyshallbe Common Propertyto be maintainedby
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