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HomeMy WebLinkAboutFile Documents.209 E Bleeker St.0320.2017 (159).ARBKP.O. Box 3901 Eagle, Colorado 81631 YARNELL CONSULTING & CIVIL DESIGN, LLC (970) 323-7008 • 1/15/2024 229 Midland Ave. Basalt, Colorado 81621 209 East Bleeker Street Page 1 of 2 Subject: 209 East Bleeker Street Stormwater Best Management Practices Maintenance Plan In general, the drainage design for this property employs vegetated swales, inlets, and below-grade piping to convey runoff generated on the site to one of two locations on the site. First, the hardscape along the rear of the home is tributary to a gutter that conveys drainage west to an area of cobble riprap near the west property corner. In this location, water is infiltrated through the cobble into the on-site soils. The remainder of the site is tributary to a gravel bed within the recessed area in the northeast quadrant of the site. Again, water is infiltrated through the gravel and into the soils beneath. Maintenance associated with the storm water infrastructure of the project generally requires that built-up sediment be removed from the vegetated swales, inlets, and piping to ensure they maintain capacity and conveyance capability. If any portion of the swales remain wet and squishy, it may indicate the need to re-grade the swale. The two (2) areas of rock slated to receive and infiltrate drainage shall be inspected to ensure water continues to flow freely into them. In the front yard, lamb’s tongues release water through the sheet steel site wall and onto the rock. At the southwest corner of the property, water flows from the curb & gutter onto the riprap pad. There are no clean-outs or other structures required to access the gravel bed. At a minimum, these areas should be inspected annually. Periodic removal of sediments and pollutants may be necessary when clogging reduces infiltration capacity to a point where the area does not completely dry out after 72 hours without precipitation. All maintenance shall be done by the owner or his property manager. The city’s engineering department will also inspect the stormwater infrastructure on a regular basis to ensure it is being maintained. For more information, refer to Table 2 below which is Table 8.12 within the city of Aspen’s Urban Runoff Management Plan. P.O. Box 3901 Eagle, Colorado 81631 YARNELL CONSULTING & CIVIL DESIGN, LLC (970) 323-7008 • 1/15/2024 229 Midland Ave. Basalt, Colorado 81621 209 East Bleeker Street Page 2 of 2 Table 1: Maintenance Recommendations for Gravel Beds Required Action Maintenance Objectives Frequency Inspections Inspect gravel bed areas to determine if voids are allowing acceptable infiltration. Routine – Annual inspection of hydraulic performance. Vegetative care Occasional weed removal to limit vegetation. Maintain surfaces of rock that are free of any vegetation or soil that would inhibit water movement down into the rock. Routine – Depending on aesthetic requirements. Debris and litter removal Remove debris and litter from detention area to minimize clogging of the sand media. Routine – Depending on aesthetic requirements. Rock removal and replacement The voids in the rock will begin to clog with time as sediment and other materials accumulate in them. This layer will need to be removed and replaced to rehabilitate infiltration rates. Every 5 to 15 years, depending on the infiltration rates needed to drain the WQCV in 12 hours or less. May need to do it more frequently if exfiltration rates are too low to achieve this goal.