Stormwater Quality Design Manual (May 2007) - City of Sacramento ...

Runoff Reduction Control Measure Fact SheetAlternative Driveway DesignHow do Alternative Driveways work?Driveways can comprise a significant portion of the total transportation network in a conventionalsuburban residential development. Alternative driveways reduce a development’s total directly connectedimpervious surface by using permeable materials, reducing the amount of pavement, paving area and/orby draining to landscaped areas. This, in turn, reduces the runoff and may provide incidental pollutantremoval. Alternative driveway designs are easily adopted into most residential construction projects, canimprove the aesthetics, and, if incorporated early in project design, may reduce the size and associatedcost of treatment controls.Planning and Siting Considerations• Consult a geotechnical engineer as to the suitability of each type of Alternative Driveway forspecific load requirements.• For Alternative Driveways using porous pavement, see planning and siting considerations on thePorous Pavement Fact Sheet elsewhere in this chapter• Specific design considerations apply to each type of Alternative Driveway (see variationsdiscussed below).VariationsFour types of Alternative Driveways are discussed in this fact sheet: 1) pervious driveway, 2)“Hollywood” driveway, 3) disconnected driveway, and 4) shared driveway. Alternative designs may beacceptable on a case-by-case basis; check with the local permitting agency for verification beforeproceeding with design.Pervious Driveway. Photo: Carrera ConstructionPervious DrivewayPervious driveways allows water to pass through the drivewaysurface via void spaces in the material and/or betweenunits. Various types of pavement may be used to make thedriveway surface permeable: pervious concrete or asphalt,modular block, cobblestone block or porous gravel (seePorous Pavement Fact Sheet elsewhere in this chapter fordetails).DesignCriteria: SeeTable AD-1for designcriteria. Also,refer to thePorousPavement factSheet.“Hollywood” DrivewayA Hollywood Driveway, where only the wheel tracks arepaved with concrete, is a viable, inexpensive design if the driveway is straight. The center strip can be leftopen to be planted with grass or groundcover, or filled with a permeable material such as gravel, modularblock pavement, or pervious pavement if water conservation/ irrigation is a concern.Design Criteria: See Table AD-1 for design criteria.Other names: ribbon driveway, paving-under-wheels driveway“Hollywood” Driveway in Natomas area, Sacramento,CA. Photo: ECORP ConsultingStormwater Quality Design Manual for the Sacramento and South Placer RegionsAD-2 May 2007