Operations + Maintenance (O+M

LTWC Rain Garden Operation + Maintenance (O+M) Plan

rain gardens Rain Gardens are vegetated surface reservoirs used to collect and treat stormwater runoff from impervious surfaces by allowing the pollutants to settle and filter out as the water percolates through vegetation and soil mediums before infiltrating into the ground below or being piped to its downstream destination.

Rain Gardens can be used to help fulfill a site’s required landscaping area requirement and should be integrated into the overall site design. Numerous design variations of shape and planting scheme can be used to fit the character of a site.

rain garden design goals The rain garden shall infiltrate stormwater within 24 hours. All facility components and vegetation shall be inspected for proper operations and structural stability, at a minimum, quarterly for the first 2 years from the date of installation, 2 times per year thereafter, and within 48 hours after each major storm event.

rain garden O+M goals Logs shall be kept by the facility owner demonstrating the following items have been inspected and are being maintained properly:

• Access to Rain Gardens shall be safe and efficient, allowing ease of maintenance. • Debris and Litter shall be removed to prevent channelization, clogging, and interference with plant growth. Fallen leaves and debris from deciduous plant foliage shall be raked and removed. • Erosion Damage shall be identified and controlled when soil is exposed or erosion channels are forming. • Infiltration: If Rain Garden does not allow stormwater to infiltrate, remove the top 2-3 inches of mulch and soil and replace with mulch that meets original specifications. To reduce this issue in the future, install a sediment drop at the inlet. If mulch replacement does not solve the issue, gravel and soil shall be replaced to correct low infiltration rates. • Mulch shall be removed and replenished annually to ensure pollutant removal and healthy plant growth.

• Nuisance Vegetation (such as blackberries and English Ivy) shall be removed when discovered. • Inlets (water flowing into facility) shall be cleared when water flow is plugged to ensure unrestricted stormwater flow to the rain garden. • Outlets (water flowing out of facility) shall be cleared when water flow is plugged. • Overflows (water to city pipes) shall be cleared when water flow is plugged. • Stabilizing Rocks shall be put back into place if rocks are scattered from the force of water flow. • Sedimentation build-up shall be hand-removed with minimum damage to vegetation. • Slopes that have exposed soil need to be replanted to stabilize banks. • Vegetation shall provide 90% coverage and be healthy and dense enough to provide filtering while protecting underlying soils from erosion. • Vegetation Maintenance will be minimal. Cut back plants when they have died and remove from the facility. Grasses are not to be cut back until March, or after heavy rains have past.

Spill Prevention Measures shall be exercised on site when handling substances that contaminate stormwater. Release of pollutants shall be corrected as soon as identified.

Non-Chemical Pest Control measures shall be taken to prevent development of insects, mosquitoes, and rodents. No spraying of any herbicide, fungicide or pesticide in facility.

Fertilizers shall only be applied after March or once the heavy rains have passed. Only organic fertilizers should be used in rain gardens, and only as necessary. No chemical fertilizers.