Low Impact Development in Placerville ...
City of Placerville
Low Impact Development in Placerville: Bioswales & Bioretention Facilities CITY OF PLACERVILLE DEVELOPMENT SERVICES PLANNING DIVISION 3101 CENTER STREET PLACERVILLE,CA 95667 PHONE (530)642-5252 FAX (530) 295-2510
Benefits of LID Stormwater Management Improves the water quality of streams, creeks, and rivers Reduces flood risk by reducing flow volume Recharges groundwater resources Cost Effective compared to conventional stormwater technology Aesthetically pleasing while environmentally friendly
Low Impact Development (LID) is an approach to stormwater management modeled after nature. LID methods, such as bioswales, rain gardens, and bioretention facilities can improve water quality, reduce flood risks, and conserve water resources while meeting development standards in an economical sustainable way. What are bioswales and bioretention facilities? Bioswales and bioretention facilities are landscaped areas designed to capture stormwater and slowly filter out pollutants before the water reaches streams, creeks, and rivers. Using specific native plants and soil, the landscaped area can mimic the natural water cycle, storing water temporarily in gentle depressions as the biotic environment absorbs pollutants. Where can we use bioswales and bioretention facilities? Bioswales, rain gardens and bioretention facilities can be used in public, residential, and
commercial development and redevelopment. Medians, parking lot islands, ditches, and home lawns are cost-effective and aesthetically pleasing ways to incorporate these
methods into the existing landscape.
Bioswales Bioswales work to filter and slowly convey stormwater to a drainage system, similar to a dry stream channel. These are typically located along a road or highway in place of a drainage ditch or pipe. Swales
should be at least 100 feet in length with 0.52.5 percent slope to provide enough time for pollutant removal. Increasing the length and adding check dams or rocks will further slow the water flow rate. Swales
can be easily included with existing drainage systems.
LID in Placerville: Biosw ales, Rain Gardens, and Bioretention Facilities
Operations and Maintenance Regular
Inspect for signs of erosion or obstructions Remove any weeds or invasive plants Remove trash and debris that could clog the drain Check facility 48 hours after a rain to make sure there is no standing water
Seasonal Replenish mulch to a depth of 3 inches Seasonally irrigate to ensure plant survival during dry months
Bioretention Facilities Bioretention facilities are any depressed landscape feature filled with porous soil and covered with a thin layer of mulch. These facilities are designed to store water short period of time to remove pollutants, rather than convey water like bioswales. Rain Gardens Rain gardens are the most common design for incorporating LID stormwater management
into residential and commercial landscaping. The garden is lowered below the impervious surfaces so water can enter into the bed infiltrate the soil. Rain gardens need to be appropriately designed to drain quickly and avoid erosion. Consider including an “overflow” area, such as a storm drain, in case the storm water volume exceeds what the rain garden can hold.
Mini-bioretention Facilities: Tree Filters
should be a 3 inch layer of mulch or organic material that will filter pollutants and provide habitat to microorganisms the soil needs.
Recommended Plant Species within the ponding area
One option easily integrated into urban streets is filters in tree planter boxes. This can both capture runoff and irrigate the tree. The water would enter the box, infiltrate the soil and filter media, and then exit into an underdrain connected to the storm water drainage system or straight into the soil.
Avoid Using any salt, fertilizer, or pesticide in these facilities Storing leaves or snow in facilities
Does LID Work? The University of Wisconsin, Madison, found these pollutant removal rates in the study “Design Guidelines for Stormwater Bioretention Facilities.”
Pollutant Total Phosphorous Metals Total Kjeldalh nitrogen Total Suspended Solids Ammonium Organics Bacteria
Removal 80% >90% 65-75% 90% 60-80% 90% 90%
Design Bioretention facilities and bioswales share the same basic features. A grass buffer slows down the velocity of the runoff followed by a sand buffer spreads flow over the filtration area. Infiltration occurs in the planting soil that sits in an 18 inch sand bed. This will create the ponding area where water will be stored or conveyed. In the soil bed
Plant species planted in the bioswale or bioretention facility should be native, droughttolerant, low maintenance, and should not require any fertilizer.
California Wild Rose Rose california California Meadow Sedge Carex pansa Outside of ponding area Common Yarrow Achillea millefollium
Works Referenced: 1. “Low Impact Development in Northern Nevada: Bioretention” University of Nevada Cooperative Extension, 2. “Design Guidelines for Stormwater Bioretention Facilities” University of Wisconsin, Madison 3. “CASQA Technical Assistance Memo” California Stormwater Quality Association Prepared for the City of Placerville by Allison Holmstedt Design Schematic provided by Paris Coyne
Works Referenced: 1. “Low Impact Development in Northern Nevada: Bioretention” University of Nevada Cooperative Extension, 2. “Design Guidelines for Stormwater Bioretention Facilities” University of Wisconsin, Madison 3. “CASQA Technical Assistance Memo” California Stormwater Quality Association Prepared for the City of Placerville by Allison Holmstedt Design Schematic provided by Paris Coyne
Works Referenced: 1. “Low Impact Development in Northern Nevada: Bioretention” University of Nevada Cooperative Extension, 2. “Design Guidelines for Stormwater Bioretention Facilities” University of Wisconsin, Madison 3. “CASQA Technical Assistance Memo” California Stormwater Quality Association Prepared for the City of Placerville by Allison Holmstedt Design Schematic provided by Paris Coyne
Low Impact Development in Placerville: Bioswales & Bioretention Facilities CITY OF PLACERVILLE DEVELOPMENT SERVICES PLANNING DIVISION 3101 CENTER STREET PLACERVILLE,CA 95667 PHONE (530)642-5252 FAX (530) 295-2510
Benefits of LID Stormwater Management Improves the water quality of streams, creeks, and rivers Reduces flood risk by reducing flow volume Recharges groundwater resources Cost Effective compared to conventional stormwater technology Aesthetically pleasing while environmentally friendly
Low Impact Development (LID) is an approach to stormwater management modeled after nature. LID methods, such as bioswales, rain gardens, and bioretention facilities can improve water quality, reduce flood risks, and conserve water resources while meeting development standards in an economical sustainable way. What are bioswales and bioretention facilities? Bioswales and bioretention facilities are landscaped areas designed to capture stormwater and slowly filter out pollutants before the water reaches streams, creeks, and rivers. Using specific native plants and soil, the landscaped area can mimic the natural water cycle, storing water temporarily in gentle depressions as the biotic environment absorbs pollutants. Where can we use bioswales and bioretention facilities? Bioswales, rain gardens and bioretention facilities can be used in public, residential, and
commercial development and redevelopment. Medians, parking lot islands, ditches, and home lawns are cost-effective and aesthetically pleasing ways to incorporate these
methods into the existing landscape.
Bioswales Bioswales work to filter and slowly convey stormwater to a drainage system, similar to a dry stream channel. These are typically located along a road or highway in place of a drainage ditch or pipe. Swales
should be at least 100 feet in length with 0.52.5 percent slope to provide enough time for pollutant removal. Increasing the length and adding check dams or rocks will further slow the water flow rate. Swales
can be easily included with existing drainage systems.
LID in Placerville: Biosw ales, Rain Gardens, and Bioretention Facilities
Operations and Maintenance Regular
Inspect for signs of erosion or obstructions Remove any weeds or invasive plants Remove trash and debris that could clog the drain Check facility 48 hours after a rain to make sure there is no standing water
Seasonal Replenish mulch to a depth of 3 inches Seasonally irrigate to ensure plant survival during dry months
Bioretention Facilities Bioretention facilities are any depressed landscape feature filled with porous soil and covered with a thin layer of mulch. These facilities are designed to store water short period of time to remove pollutants, rather than convey water like bioswales. Rain Gardens Rain gardens are the most common design for incorporating LID stormwater management
into residential and commercial landscaping. The garden is lowered below the impervious surfaces so water can enter into the bed infiltrate the soil. Rain gardens need to be appropriately designed to drain quickly and avoid erosion. Consider including an “overflow” area, such as a storm drain, in case the storm water volume exceeds what the rain garden can hold.
Mini-bioretention Facilities: Tree Filters
should be a 3 inch layer of mulch or organic material that will filter pollutants and provide habitat to microorganisms the soil needs.
Recommended Plant Species within the ponding area
One option easily integrated into urban streets is filters in tree planter boxes. This can both capture runoff and irrigate the tree. The water would enter the box, infiltrate the soil and filter media, and then exit into an underdrain connected to the storm water drainage system or straight into the soil.
Avoid Using any salt, fertilizer, or pesticide in these facilities Storing leaves or snow in facilities
Does LID Work? The University of Wisconsin, Madison, found these pollutant removal rates in the study “Design Guidelines for Stormwater Bioretention Facilities.”
Pollutant Total Phosphorous Metals Total Kjeldalh nitrogen Total Suspended Solids Ammonium Organics Bacteria
Removal 80% >90% 65-75% 90% 60-80% 90% 90%
Design Bioretention facilities and bioswales share the same basic features. A grass buffer slows down the velocity of the runoff followed by a sand buffer spreads flow over the filtration area. Infiltration occurs in the planting soil that sits in an 18 inch sand bed. This will create the ponding area where water will be stored or conveyed. In the soil bed
Plant species planted in the bioswale or bioretention facility should be native, droughttolerant, low maintenance, and should not require any fertilizer.
California Wild Rose Rose california California Meadow Sedge Carex pansa Outside of ponding area Common Yarrow Achillea millefollium
Works Referenced: 1. “Low Impact Development in Northern Nevada: Bioretention” University of Nevada Cooperative Extension, 2. “Design Guidelines for Stormwater Bioretention Facilities” University of Wisconsin, Madison 3. “CASQA Technical Assistance Memo” California Stormwater Quality Association Prepared for the City of Placerville by Allison Holmstedt Design Schematic provided by Paris Coyne
Works Referenced: 1. “Low Impact Development in Northern Nevada: Bioretention” University of Nevada Cooperative Extension, 2. “Design Guidelines for Stormwater Bioretention Facilities” University of Wisconsin, Madison 3. “CASQA Technical Assistance Memo” California Stormwater Quality Association Prepared for the City of Placerville by Allison Holmstedt Design Schematic provided by Paris Coyne
Works Referenced: 1. “Low Impact Development in Northern Nevada: Bioretention” University of Nevada Cooperative Extension, 2. “Design Guidelines for Stormwater Bioretention Facilities” University of Wisconsin, Madison 3. “CASQA Technical Assistance Memo” California Stormwater Quality Association Prepared for the City of Placerville by Allison Holmstedt Design Schematic provided by Paris Coyne
