6200 12TH DR SE 2020-10-22 - Laserfiche WebLink

of excess nutrients, rain garden plantings should not be fertilized. Plant selection, a rich soil mix at time of installation, and regular mulching should provide sufficient nutrients to plantings in these areas. • Keep Water Flowing: After heavy storms, check the inflow and overflow areas to make sure they are still intact and can continue to carry water into and out of the rain garden. Remove any debris or litter in the rain garden that may interfere with flow. Keep the inflow pipe accessible and flush out pipe if necessary. Look for areas where water may not be soaking into the ground. This may be due to fine sediment or compaction of the soil. Remove sediment that may be building up and rake the soil surface. If you suspect compaction, break up and loosen the soil when it is not saturated. • Minimize Exposed Soil and Erosion: Sediment flowing into your rain garden can clog the soil mix and slow drainage. Sediment carried out of the rain garden can harm streams and wetlands in many ways, including transporting pollutants, covering fish spawning areas, and filling stream channels and pools. To guard against soil erosion problems: • Check the rain garden for areas of exposed soil, particularly in the fall before the wet season begins, as well as during the winter. • Replenish mulch areas throughout your rain garden—on the sides and bottom of the rain garden and also around the perimeter (and on the berm if applicable). • Maintain a healthy cover of plants. • Maintain a decorative cobble rock pad to protect the ground and prevent erosion where concentrated water flows into the rain garden from a pipe or swale. • If sediment is deposited from water entering the rain garden, immediately determine the source and stabilize the area. • If there is a localized area of erosion, consider stabilizing the area with rocks to spread out the flows causing erosion. If there are already rocks in this area, use larger rocks or cover a larger area with rock to spread out the flow. • If erosion is occurring at the inflow and overflow locations, you may need to extend the cobble rock in these areas to disperse water flow. • If erosion persists, water may be flowing into the rain garden too rapidly, In this case, the slope of the pipe or swale directing water may need to be reduced, or the amount of water flowing into the rain garden may need to be decreased. Adding small rock check dams every few feet in the inflow can slow water and reduce erosion. • Replenish Mulch: Mulch prevents erosion, controls weeds, retains moisture, adds organic material to the soil, and improves drainage. Every year check the mulch layer and, if needed, replenish to maintain a depth of 2 to 3 inches. Spread mulch between plants and on bare ground. Added mulch should be shredded or chipped hardwood or softwood. Mulch can be applied any time of year, but maintaining a sufficient mulch layer for the dry summer and rainy winter months is particularly beneficial. Avoid using mulch that has been stockpiled for extended periods of time since •