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Home My WebLink About015 - Appendix H - Storm Water Maintenance Plan i 234 East Babcock Street �� I � Suite 3 Engineering r tdhengineering.com Bozeman, MT 59715 l _ '�. y �` +,..� _� � �, w�`�'':� �=�.:" � `� �� -�',-` �;��.,��► ��,;, ��-� ` � �`�� '�'��,�'�.�`� .'�; .��:� ; �� '� ��; �� _�� .�`��`� ..� ,� �� .;�� .�� Q:�:;� ` ��• ,�.''� \n4'A i", �� \ +s � '� � �y .�„� �� y��.f - . I,ws, ,�t";'` �.� `�, ..1.�1�.7!•�. y+� ,'�,.` �{ .ti i;�' � �91 ..:x'. ��' `� �' � ' . c �,,M ' '�� 1 � � � .��.. .,,�. , � �. . ;,,. .� �:. _ . ON-SITE STORM WATER MAINTENANCE PLAN • • • ' • ' : � • : • . � . . •'�,ONT q/V�q'••. CLIENT ENGINEER ' * ` TIMOTHY R.` * ' Lake Flato Architects TD&H Engineering BLYSTONE 311 Third Street 234 East Babcock Street, Suite 3 San Antonio, TX 78205 Bozeman, MT 59715 �-o�'•. o./,$� E � �� .` Engineer: Tim Blystone, PE �'•�� ENS�- � G��•' . SS�ONALE� . • : • : 1 • • • • ' 1 . MONTANA WASHINGTON IDAHO NORTH DAKOTA PENNSYLVANIA WALLACE WORKS MINOR SUBDIVISION STORM WATER MAINTENANCE PLAN PURPOSE AND INTRODUCTION This maintenance plan identifies the recommended maintenance procedures necessary for the proper function of the on-site storm water management system proposed at the Wallace Works Minor Subdivision project in Bozeman, Montana. For the purpose of this plan, the on-site storm water management system includes stormwater conveyance paths and pipes within the two lots of the property; the subsurface retention chambers and inlets/manholes in the central plaza and parking lot; and the existing PVC stormdrains in East Tamarack Street and North Wallace Avenue to the north and east of the property. The maintenance responsibility for all on-site stormwater management infrastructure outside of the public right-of-way belongs to the property owners association (POA). The POA may delegate routine inspection and maintenance responsibilities to the on-site facility operations management team or may hire a qualified professional entity or individual to perform certain monitoring and maintenance tasks as necessary. A log shall be kept for all required inspections and maintenance. These logs shall be made available to the City of Bozeman Public Works Department for review as requested. A sample maintenance log is included in the attached Appendix. The POA shall be responsible for levying annual assessments to provide for the maintenance, repair, and upkeep of all on-site stormwater infrastructure outside of the public right-of-way. STORM WATER MANAGEMENT SYSTEM The on-site storm water management system of which the POA is responsible for maintenance includes on-site curb and gutter, curb inlets and associated piping, area inlets and associated piping, drainage chases, roof drain piping, subsurface infiltration galleries, and any storm manholes outside of the public right-of-way. These various components of storm water management infrastructure are designed to collect, convey, clean, detain, and/or infiltrate storm water runoff that is generated on the property before it leaves the site or enters local waterways. Storm water systems require proper maintenance to prevent sediment clogging, overgrown vegetation, erosion of detention ponds, obstruction of inlets, pipes, and structures, and prolonged standing water. Such issues may result in downstream pollution, unpleasant odors, unsightly areas, nuisance insects, or algae blooms, and must be mitigated. Scheduled inspections, times of inspections, locations inspected, maintenance completed, corrective actions taken, and any modifications or reconstruction performed shall be documented in the maintenance logs to be readily available upon request. Disposal of accumulated sediment must be in accordance with all applicable local, state and federal regulations. Wetlands are not anticipated to be encountered during maintenance activities for the on-site subsurface infiltration facilities. However, maintenance of off-site locations where outlet pipes or overflows discharge to protected water bodies within wetland areas may require wetland or stream bank permitting. If unsure of the regulatory status of wetland features observed at the site, consult the local authorities prior to undertaking any activities that may cause disturbance. WALLACE WORKS MINOR SUBDIVISION Storm Water Maintenance Plan 621-099 1 STORM WATER MAINTENANCE PROCEDURES The following maintenance procedures are intended to prolong the life of installed system components and ensure their continued functionality: General Storm Water System Maintenance— 1. Parking lot areas, curbs & gutters, drainage chases, and area drains should be cleared of leaves and other debris once after primary leaf drop in the fall and once after snow melt in early spring at a minimum. This will minimize the potential for debris to enter the system which could lead to premature clogging of structures, reduced storage capacity, and/or blockage of inlets. 2. Inspect the storm drain inlets, overflow structures, and cleanouts, for sediment build-up or clogging and flush/clear as needed. Inspect for snow/ice buildup at least once weekly during winter months and clear the inlet as needed. Do not pile snow over inlets. 3. Snow storage should be performed in designated areas during winter months and should not be allowed to be piled in front of or over inlets. Piled snow around or over the inlets could block early snowmelt run-off from entering the system, possibly causing overflows and icy conditions. 4. Sanding of the parking lots and drive aisles should be done sparingly or avoided completely. Sand or other sediment on the parking lot will likely be washed into stormwater system components which can lead to buildup and reduced capacity or blockages over time. Sub-surface Infiltration Gallery(StormTech system) Maintenance — The subsurface infiltration systems are designed with isolator rows that capture the "first flush" of pollutants from runoff events. The isolator rows are equipped with inspection ports and direct manhole access for maintenance. The isolator row should be inspected for sediment buildup once every 6-months during the first year of operation, and once a year after that. Use the general preventative measures described above to help reduce sediment build up and clogging. Clean out sediment buildup as necessary following the attached manufacturer recommended procedures. WALLACE WORKS MINOR SUBDIVISION Storm Water Maintenance Plan 621-099 2 APPENDIX Sample Maintenance & Inspection Log StormTech Isolator Row O&M Manual Storm Water Facilities Inspection and Maintenance Log Facility Name Begin Date End Date Date Location Facility Description Inspected Cause for Exceptions Noted Comments and by: Inspection Actions Taken Instructions: Record all inspections and maintenance for all storm water facilities on this form. Use additional log sheets and/or attach extended comments or documentation as necessary. Save all completed logs in one place and have them readily available for the City of Bozeman's review upon request. ■ Location —Specify the exact location of the facility either by its name, facility ID or physical location. ■ Inspected by— Note all inspections and maintenance on this form, including the required independent annual inspection. ■ Cause for inspection — Note if the inspection is routine, pre-rainy-season, post-storm, annual, or in response to a noted problem or complaint. ■ Exceptions noted — Note any condition that requires correction or indicates a need for maintenance. ■ Comments and actions taken — Describe any maintenance performed and need for follow-up. 1 , � ' � 1 � � •� i ,� � � ,�y '-_" F�� ,�..e �;�� -- .s ii� t�Ji' �� !\ . .. �; ' 'r� ; 1�� t �,�� :.b. , '�'I ��-� I i, �� {��yj, A � ,�.._�. � i� J� — _ �v�� . '� ��i. .Syi: ! �C, t 'S �L� y" � \ -%"r ' � '�",.`''`.�'r' �� R� i�` �� I � 1� :%. •� ��( � �� • '��r; ' ? 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F� y ' I��II��I��I/��/��/I ..�� I H`-.. /�.`�'�' A - '��1��%/��/�� Ij' ' \ '�?�, �':. - ♦ ��.�.'.r �/' - � jl�jl��jl��%/�%/��%/�' �`r � ,�7 , ��i��i��ii��ii��v � � I t�1 1;: - II�I�11�l��l��l�� , � �� 'r�;? , I��jl��jl��l��l�� ' �'' � ��' ��I��II��I��ll��l��l� ' � 5� ��,, � � f"; ��,� �j��j�jl�jl�I��l��l�' � �� '- �`�� - �� I �l /I �I ��;;; ur �� , �E ��I��I��I��I��/��1� � ,?,�� ., .Ar� �: �I��II��I��I��1��1��1��/l� � eF�� , a�_ � �� II��I��I��I��II��1��/1 i; `�� 'lil�ll�lj��l�ll�ll�l��/l� '•' ,�1 � , ��' �� , '�s�. � /�� I�I��I��I��I��I��I �i�;"�'�`' ' .�" �� . /ii_ �'I��I��I��I � �� r-- ,�� /%�� Il��j��jl�j ��,�x�, ��a ..+�'" ' � ��//�Z ��I��jl��l� i+'� �� - � �/� 'I I�I) �� `': ��j i� �� 't /n � �� , � �!��• �}� ' �� , � � Y ' �////j1�', r _ � M �� ;�j�l r7�'� � ; �,-" ''�� j��. u � , , ,' . ) � �;,,,,,,,, � ..,, , - a � � � ,, , � � ,' "„ , .. _ :, , � ,,,,,,,,,,, ,„ � , ,.� /// /i��1�f��'�'��i�� -. �� r ` / . I 1 1. �t 1 - o� I 1 . � IIIII�� i��li�� f �/�; '� A, � ��. �� : ' 5 �� 1�� ` ' � � K � � ° 'a � - k .J% �.f/ ` , r� '� ; � / ;p �t� � �� J 's�� .�1 �� w� �u�. � , - , 4. % .� — — -��{ , � 4 � � �; �. , � x, � '�?�� , � I ,l � 1 , �� i�i �..� . '� t � � <� �` , � . / , ,�i �.'� r '.��. �._;� 'r � }` _ �� . � % ��e' , .� i.. ., . .. tL��. . � - , . • Y � �'r. �h. .�y�� THE ISOLATOR° ROW � \ � INTRODUCTION ��--�— An important component of any Stormwater Pollution Prevention �/. Plan is inspection and maintenance.The StormTech Isolator Row is % a technique to inexpensively enhance Total Suspended Solids(TSS) removal and provide easy access for inspection and maintenance. THE ISOLATOR ROW The Isolator Row is a row of StormTech chambers, either SC-160LP, SC-310, SC-310-3, SC-740, DC-780, MC-3500 or MC-4500 models, that is surrounded with filter fabric and connected to a closely located manhole for easy access.The fabric-wrapped chambers provide for Looking down the Isolator Row from the settling and filtration of sediment as storm water rises in the Isolator manhole opening,woven geotextile is shawn between the chamber and stone base. Row and ultimately passes through the filter fabric.The open bottom chambers and perforated sidewalls(SC-310,SC-310-3 and SC-740 models)allow storm water to flow both vertically and horizontally out of -�'��rr�- ` �, the chambers.Sediments are captured in the Isolator Row protecting � �i - the storage areas of the adjacent stone and chambers from sediment ;�;;�,,:� �w�-�� accumulation. ,r-- -�- - Two different fabrics are used for the Isolator Row.A woven geotextile � fabric is placed between the stone and the Isolator Row chambers. The tough geotextile provides a media for storm water filtration and provides a durable surface for maintenance operations. It is also „, � designed to prevent scour of the underlying stone and remain intact � � j� � y►w+w"' during high pressure jetting.A non-woven fabric is placed over the � y�� y' chambers to provide a filter media for flows passing through the ' '�� ' ��_�''�' perforations in the sidewall of the chamber.The non-woven fabric is not .-� ```�' '� � � +� required over the SC-160LP, DC-780, MC-3500 or MC-4500 models as these chambers do not have perforated side walls. StormTech Isolator Row with The Isolator Row is typically designed to capture the"first flush"and Overflow Spillway(not to scale) offers the versatility to be sized on a volume basis or flow rate basis. oPT�oNA� An upstream manhole not only provides access to the Isolator Row but PRE-TR�TMENT typically includes a high flow weir such that storm water flowrates or volumes that exceed the capacity of the Isolator Row overtop the over �so�To Row flow weir and discharge through a manifold to the other chambers. '%, _ '� = =' "=" ="" The Isolator Row may also be part of a treatment train. By treating � ��°, ;,-� -��„,-- -��,� storm water prior to entry into the chamber system,the service life can "'ANw,TH �� be extended and pollutants such as hydrocarbons can be captured. °"ER WER � Pre-treatment best management practices can be as simple as � deep sump catch basins, oil-water separators or can be innovative � storm water treatment devices.The design of the treatment train and � � selection of pretreatment devices by the design engineer is often EO°EAOR'R driven by regulatory requirements.Whether pretreatment is used or not, � the Isolator Row is recommended by StormTech as an effective means � to minimize maintenance requirements and maintenance costs. � Note: See the StormTech Design Manual for detailed information on � designing inlets for a StormTech system, including the Isolator Row. oPT�oNA�— ACCESS STORMTECH CHAMBERS �I I � I � I I • �I I I , ISOLATOR ROW �� T/M A INTENA NrF � � INSPECTION ;� The frequency of inspection and maintenance varies by location.A �` routine inspection schedule needs to be established for each individual location based upon site specific variables.The type of land use(i.e. - , ; � industrial,commercial, residential),anticipated pollutant load, percent ;, � imperviousness, climate, etc.all play a critical role in determining the '`� actual frequency of inspection and maintenance practices. �` At a minimum, StormTech recommends annual inspections. Initially, the Isolator Row should be inspected every 6 months for the first year of operation. For subsequent years,the inspection should be adjusted based upon previous observation of sediment deposition. The Isolator Row incorporates a combination of standard manhole(s)and strategically located inspection ports (as needed).The inspection ports allow for easy access to the system from the surface, eliminating the need to perform a confined space entry for inspection purposes. If upon visual inspection it is found that sediment has accumulated, a stadia rod should be inserted to determine the depth of sediment.When the average depth of sediment exceeds 3 inches throughout the length of the Isolator Row,clean-out should be performed. MAINTENANCE The Isolator Row was designed to reduce the cost of periodic maintenance. By"isolating" sediments to just one row,costs are dramatically reduced by eliminating the need to clean out each row of the entire storage bed. If inspection indicates the potential need for maintenance, access is provided via a manhole(s) located on the end(s)of the row for cleanout. If entry into the manhole is required, please follow local and OSHA rules for a confined space entries. Maintenance is accomplished with the JetVac process.The JetVac process utilizes a high pressure water nozzle to propel itself down the Isolator Row while scouring and suspending sediments.As the nozzle is retrieved,the captured pollutants are flushed back into the manhole for vacuuming. Most sewer and pipe maintenance companies have vacuum/JetVac combination vehicles. Selection of an appropriate JetVac nozzle will improve maintenance efficiency. Fixed nozzles designed for culverts or large diameter pipe cleaning are preferable. Rear facing jets with an effective spread of at least 45"are best. Most JetVac reels have 400 feet of hose allowing maintenance of an Isolator Row up to 50 chambers long.The JetVac process shall only be performed on StormTech Isolator Rows that have AASHTO class 1 woven geotextile(as specified by StormTech)over their angular base stone. StormTech Isolator Row(not to scale) Note:Non-woven fabric is only required over the inlet pipe connection into the end cap for SC-160LP,DC-780,MC-3500 and MC-4500 chamber models and is not required over the entire Isolator Row. / � OPTIONALINSPECTIONPOF2T SC-]40,SC-310;COVER ENTIRE ISOLATOR ROW WITH ADS _ cEosvurHEncssoirNou-wovEN cEorExn�E ' SC-]30:8'(2.4 m)MIN WIDE ' // l�� SC310_5'(1 5 m)MIN WIOE STORMTECH CHAMBER MC�4500,MC-3500,DC-]80,SC�1fi0LP;COVER PIPE GONNECTION TO END CAP WITH ADS // GEOSYNTHETICS 601T NON-WOVEN GEOTEXTILE STORMTECH EN�GAP CATCH BASIN � ' �I � , � � OR MnNHo�e � �� ii�ii II'�I �II � 14 li li i ��iltl II II I I� I II II I�I ` li iYl.i�� iuiiili . @ Ifil�i uri�i�. VI�- oll� �II ��Ill�lii l e� k 1114��1 il I' �I ,j� ' � � ��sllp�ll�i SUMP DEPTH TBD BV SITE DESIGN ENGINEER (26"[60�mm]MIN REGOMMEN�E�) TVJO LNVERS OF A05 GEOSYNTHETICS 315WT WOVEN GEOTEXTILE BETWEEN FOUNDATION STONE AN�CHAMBERS.CONTINUOUS FABRIC WITHOUT SEAMS I 24"(fi00 mm)HDPE HCCESS PIPE REQUIREO�.MC�45�0.MC-3504,SC-]40,DC-]80 10.3'(3.1 m)MIN WIDE'.MG-0500 12"(300 mm)HDPE ACGESS PIPE RE�UIRED-SG3�0 825'(2.5 m)MIN WI�E�.MC3500 8"(200 mm)HDPE ACCE55 PIPE REQIIIRE��.SC�160LP 5'(1.5 m)MIN W I�E�.�G)80.SC-]40 4'(1 2 ri)MIN V�iDE SGJ10,SG�60LP �L�L�L� � � STEP 1 Inspect Isolator Row for sediment. A) Inspection ports(if present) i. Remove lid from floor box frame ii. Remove cap from inspection riser iii. Using a flashlight and stadia rod,measure depth of sediment and record results on maintenance log. iv. If sediment is at or above 3 inch depth, proceed to Step 2. If not, proceed to Step 3. B)All Isolator Rows i. Remove cover from manhole at upstream end of Isolator Row ii. Using a flashlight, inspect down Isolator Row through outlet pipe 1. Mirrors on poles or cameras may be used to avoid a confined space entry 2. Follow OSHA regulations for confined space entry if entering manhole iii. If sediment is at or above the lower row of sidewall holes(approximately 3 inches), proceed to Step 2. If not, proceed to Step 3. STEP 2 Clean out Isolator Row using the JetVac process. A)A fixed floor cleaning nozzle with rear facing nozzle spread of 45 inches or more is preferable B)Apply multiple passes of JetVac until backflush water is clean C)Vacuum manhole sump as required STEP 3 Replace all caps, lids and covers, record observations and actions. STEP 4 Inspect&clean catch basins and manholes upstream of the StormTech system. ,)B)� 2 �)a) r � � i' i' � ___ � I � a � � � ,�� SAMPLE MAINTENANCE LOG � �, . ,. � 0^/15/11 6.3 fE �no�ne 1 ,' , New EensFaLLaECain, �Cxed �roi�nE Cs 4I frame aE D�M grade 9/2r+/11 b.2 0.1 f E Sorwe �riE f eLF SkS �/20/13 S.Fr o.5 ¢E Mucky ¢eet, de�r�s visibLe itn rviasnkaLe a�nd i�n N� I IsoLaEar IZaw, rnaCenEe�naence due 7!7/13 b.3 f E I a S�sEem,�eEEed ac�d vacccurned '6�A1 �. . . �. � � �� - - - - - -- - •��- - - o�� - ��.��. � I , uuu� �. ��` �� :�� StormTech Maintenance Log Project Name: Location: � ♦ StormTech� www.stormtech.com Stadia Rod Readings Fixed point to chamber Fixed point to top of Sediment Depth Date Observations/Actions Inspector bottom(1) sediment(2) (1)-(2)