Loading...
HomeMy WebLinkAboutFile Documents.701 Gibson Ave.0086-2021-BRES MAINTENANCE AND OPERATION PLAN FOR 701 GIBSON AVENUE CITY OF ASPEN COUNTY OF PITKIN, STATE OF COLORADO February 28, 2024 HCE PROJECT #:2201051.00 Please include confirmation that plan was prepared by the Civil Engineer of Record Please include an 835" x 11" copy of the as-built survey as Appendix A Include an inspection schedule and log as Appendix B Maintenance agreement must be signed by each homeowner of said property and notarized by a Notary Public. A. Introduction As part of the Certification of Occupancy, the following maintenance plan has been prepared for 701 Gibson Avenue in the City of Aspen, Colorado. B. Site Description and Drainage Pattern The site is located at 701 Gibson Avenue within the City of Aspen, County of Pitkin, State of Colorado, between Gibson Avenue and North Spring Street. The 701 Gibson property is approximately 46,800 square-feet (1.07 acres). The existing lot consists of a home, basement, patios, second-story deck, driveway, garage slab, paths, landscaping tennis court and numerous trees. The site is bordered by a private properties to the east and west, Gibson Avenue to the north and North Spring Street to the south. The site drains from the north to the south, across North Spring Street and into the Roaring Fork River at the southwest end of the property. Existing grades range from approximately 2-percent to 65+ percent. An existing storm system that was not part of the project scope includes the residential structure drainage system and three drywells that receive site drainage below the residence just above North Spring Street. The proposed construction called for some interior remodeling of the existing residence along with driveway and yard landscaping improvements. The existing, short driveway that connects the garage to Gibson Avenue was improved to include stone pavers and is the source of the change of impervious area for the site. A sidewalk, curb and gutter was installed with a curb inlet. An additional concrete area at the northeast corner of the lot was replaced with snowmelt. The disturbed impervious areas for the site are piped to the bioretention pond and treated for WQCV. Runoff will be routed by sheet flow and slot drain storm piping through the new landscaping areas to the bioretention pond. The bioretention pond have partial impervious membranes for the concrete walls, and runoff will infiltrate into the soils below the pond. WQCV and detention volumes are nested; therefore, the volume provided by the bioretention pond also meets the required detention. Runoff, greater than WQCV and detention, will overflow the pond weir and leave the site in historical fashion to the City of Aspen’s right of way and into the Roaring Fork River. This project includes “Low Impact Site Design” to mimic the natural pre-development hydraulic pattern. Storm water runoff is to be in contact with soils and plants prior to reaching the City of Aspen right-of-way. The plants and soil are to act as filters to remove pollutants. The proposed plants and soils are present along the proposed grass conveyance and within the proposed bioretention basin. The proposed drainage facilities were constructed in conformance with the City of Aspen Urban Runoff Management Plan, dated April 2010 and revised thereafter. C. Site BMP Maintenance The following Best Management Practices (BMPs) shall be implemented to prolong the life of the storm water infrastructure and to assure that the drainage facilities are functioning properly. Refer to the As-Built plan created by High Country Engineering for locations of the drainage facilities. The list below describes BMPs that shall be implemented after construction: 1. Mowing, trimming, and weed control shall be performed on a regular basis throughout the growing season. Mowing shall keep the grass to a length of no longer than six inches. Trimmings shall be picked up and removed from the mowed area or a bagging system shall be used. A mulching lawnmower may also be used. 2. All drainage facilities shall be inspected for damages on an annual basis. If structures are damaged to a point that they cannot function properly, then the structure must be replaced. 3. Leaves and debris shall be removed from the bioretention area in the spring, after snow melt and in the fall once the trees have lost their leaves to prevent obstruction of inlet pipes and outlet weir. If the drain pipes are functioning properly, water will not back up in the slot drain and overtop the driveway. Storm water shall drain to the bioretention area and infiltrate into the soils. The pipes shall be cleaned by using a brush system or a hose to flush out the debris. The pipes may need to be jetted with a high pressure water system to remove any clogged debris. 4. The proposed slot drain channel shall be inspected and cleared of rubbish and debris quarterly, as well as after large storm events. The slot drain channel can be accessed by removing the access unit at the northwest end on the drain. Remove debris from channel. Flush channels with water or high pressure washer (do not use boiling water or corrosive cleaning agents), if needed. Repair damaged surfaces where necessary with an appropriate ACO repair kit, and repair/replace joint seals as required. Clean out pipe connections if blockades or improper functioning of storm systems are observed. The slot drain grate must also be inspected and cleared frequently to make sure there is no clogging. 5. Piping with depths equal to or less 36” than shall be heat taped. 6. The bioretention basin will need to be inspected and maintained quarterly to make sure that the reservoir has not become clogged and that the reservoir is functioning properly. Minimum inspection and maintenance requirements include the following: a. Inspect detention area to determine if the sandy growth media is allowing acceptable infiltration. b. Debris and liter removal from detention area to minimize clogging of the sand media shall occur routinely. c. Occasional mowing of grasses and weed removal to limit unwanted vegetation. Maintain irrigated turf grass as 2 to 4 inches tall and non- irrigated native turf grasses at 4 to 6 inches. d. The sandy loam turf and landscaping layer will clog with time as materials accumulate on it. This layer will need to be removed and replaced to rehabilitate infiltration rates, along with all turf and other vegetation growing on the surface. This will need to be done every 5 to 15 years, depending on infiltration rates needed to drain the WQCV in 12-hours or less. Rehabilitation may need to occur more frequently if infiltration rates are too low to achieve this goal. The owners of the property will be responsible for the maintenance and upkeep of the drainage facilities. The property owner shall dispose of sediment and any other waste material removed at suitable disposal sites and in compliance with local, state, and federal waste regulations. D. Proper Function of Best Management Practices The drainage facilities will need to be inspected quarterly as well as after large storm events to assure that they are accepting all flow directed to them and to assure that they are functioning properly. Stormwater should be captured by the slot drain in the driveway and be piped to the bioretention basin. If the bioretention basin exceeds capacity, site drainage should flow over the weir of the pond onto the rip-rap below. The rip-rap should prevent erosion beneath the overflow. Bioretention (also known as porous landscape detention) BMPs function by capturing runoff and releasing it over an extended period of time (typically 12 hours for Aspen). This allows time for sedimentation and contact with vegetation for biological treatment. If the infiltration area is functioning properly, storm water will infiltrate into the filter material along the bottom of the basin. Water from a storm event should not be visible within 12 hours after a minor storm event. E. Record Keeping The above BMP plan shall prolong the lifespan of the storm water drainage facilities. The operation and maintenance of the storm water facilities shall be in compliance with the City of Aspen’s Urban Runoff Management Plan (URMP). If the owner cannot perform the routine facility checks discussed above, then they shall hire someone that can perform the duties in order to comply with the City of Aspen’s URMP. All inspections and any maintenance performed on the drainage facilities shall be recorded in inspection and maintenance logs and made readily available for review by the City of Aspen upon their request. STORMWATER BEST MANAGEMENT PRACTICES OPERATIONS AND MAINTENANCE AGREEMENT City of Aspen, Colorado THIS AGREEMENT, made and entered into this Full Name of Owner) day of _, 20 , by and between (Insert hereinafter called the "Landowner", and the City of Aspen, Colorado, hereinafter called the "City". WITNESSETH WHEREAS, the Landowner is the owner of certain real property described as (Pitkin County tax Map/Parcel Identification Number) located at and as more fully as follows, to wit: also known as, , hereinafter called the "Property"; and WHEREAS, the Landowner is proceeding to build on and develop the property; and WHEREAS, the stormwater management BMP Operations and Maintenance Plan for the property identified herein has been approved by the City, herein after called the “Plan”, which is attached hereto as Appendix A and made part hereof, as approved by the City, provides for management of stormwater within the confines of the Property through the use of stormwater management or Best Management Practices (BMPs) facilities; and WHEREAS, the City and the Landowner, its successors and assigns, agree that the health, safety, and welfare of the residents of City of Aspen, Colorado and the maintenance of water quality require that on-site stormwater management/BMP facilities be constructed and maintained on the Property; and WHEREAS, the City requires, through implementation of the Plan from the Landowners dated and attached hereto, that on-site stormwater management/BMPs as shown on the Plan be adequately constructed, operated, and maintained by the Landowner, its successors and assigns. NOW, THEREFORE, in consideration of the foregoing premises, the mutual covenants contained herein, and the following terms and conditions, the parties hereto agree as follows: 1. Construction of BMP facility by Landowner. The on-site stormwater management/BMP facilities shall be constructed by the Landowner, its successors and assigns, in accordance with the plans and specifications approved by the City and identified in the Plan. 2. Duty of Operation and Maintenance of Facility. The Landowner, its successors and assigns, including any homeowners association, shall adequately operate, inspect, and maintain the stormwater management/BMP facilities as acceptable to the City and in accordance with the specific operation, inspection, and maintenance requirements noted in the Plan. Adequate operation and maintenance is herein defined as good working condition so that these facilities are performing their design functions. 3. Duty of Documentation. The Landowner, its successors and assigns, shall document inspections, maintenance, and repairs performed and provide said documentation to the City or its representatives upon request. 4. Right of Entry on Property. The Landowner, its successors and assigns, hereby grant permission to the City, its authorized agents and employees, to enter upon the Property at reasonable times and upon presentation of proper identification, and to inspect the stormwater management/BMP facilities whenever the City deems necessary. The purpose of inspection is to follow-up on suspected or reported deficiencies, to respond to citizen complaints, and/or to assure safe and proper functioning of the facilities. The City shall provide the Landowner, its successors and assigns, copies of the inspection findings and a directive with timeline to commence with the repairs if necessary. 5. Failure to Maintain. In the event the Landowner, its successors and assigns, fails to construct, operate and maintain the stormwater management/BMP facilities in good working condition acceptable to the City, the City, its authorized agents and employees, may enter upon the Property and take whatever action(s) deemed necessary to correct deficiencies identified in the inspection report and to charge the costs of such construction or repairs to the Landowner. It is expressly understood and agreed that the City is under no obligation to install, construct, or routinely maintain or repair said stormwater management/BMP facilities, and in no event shall this Agreement be construed to impose any such obligation on the City. 6. Reimbursement by Landowner. In the event the City pursuant to this Agreement, performs work of any nature, or expends any funds in performance of said work for labor, use of equipment, supplies, materials, and the like, the Landowner, its successors or assigns, shall reimburse the City upon demand, within thirty (30) days of receipt thereof for all actual costs incurred by the City hereunder. 7. Duty to Inspect by City. The City, its employees or representatives, shall inspect the stormwater management/BMP facilities at a minimum of once every three years to ensure their continued and adequate functioning. 8. Release of City. The Landowner, its executors, administrators, assigns, and other successors in interests, shall release the City, its employees and designated representatives from all damages, accidents, casualties, occurrences, or claims which might arise or be asserted against said City, employees, and representatives from the construction, presence, existence, operative or maintenance of the stormwater management/BMP facilities by the Landowner or City. In the event that a claim is asserted against the City, its elected officials, City Officers or employees, the City shall promptly notify the Landowner and the Landowner shall defend, at its own expense, any suit based on the claim. If any judgment or claims against the City’s employees or designated representatives shall be allowed, the Landowner shall pay all costs and expenses regarding said judgment or claim. 9. Recording of Agreement running with the Property. This Agreement shall be recorded in the real property records of Pitkin County, Colorado, and shall constitute a covenant running with the Property or land, and shall be binding on the Landowner, its administrators, executors, assigns, heirs and any other successors in interests, in perpetuity. IN WITNESS WHEREOF the undersigned have hereunto affixed their signatures as of the date first above written. LANDOWNER: By:_ Print Name: State of Colorado ) :ss County of Pitkin ) The foregoing Agreement was acknowledged before me this day of , 20_ , by . My Commission Expires: Notary Public THE CITY OF ASPEN: By:_ Print Name: State of Colorado ) :ss County of Pitkin ) The foregoing Agreement was acknowledged before me this day of , 20_ , by . My Commission Expires: Notary Public Please update this page with the document from this link: https://aspen.gov/DocumentCenter/View/12064/Storm water-BMP-OM-Agreement-Template_v2023?bidId=