(a) The intent of Sections 147-147.6 of this Code is to reduce the volume of stormwater entering the City's Combined and Separate Sewer Systems and to protect and enhance the water quality of receiving waters, pursuant to, and consistent with Federal and State laws, lawful standards and orders applicable to stormwater and urban runoff control, and the City's authority to manage and operate its drainage systems.
(b) Urban runoff is a significant cause of pollution throughout California. Pollutants of concern found in urban runoff include sediments, non-sediment solids, nutrients, pathogens, bacteria, oxygen-demanding substances, petroleum hydrocarbons, heavy metals, floatables, polycyclic aromatic hydrocarbons (PAHs), trash, and pesticides and herbicides.
(c) During urban development, two important changes occur. First, where no urban development has previously occurred, natural vegetated pervious ground cover is converted to impervious surfaces such as paved highways, streets, rooftops, and parking lots. Natural vegetated soil can both absorb rainwater and remove pollutants, providing a very effective purification process. Because pavement and concrete can neither absorb water nor remove pollutants, the natural retention and purification characteristics of the land are lost, increasing the volume of stormwater entering the collection system and the concentration of pollutants within that water. Second, urban development creates new pollutant sources, including vehicle emissions, vehicle maintenance wastes, pesticides, household hazardous wastes, pet wastes, trash, and other contaminants that can be washed into the City's Separate or Combined Sewer Systems.
(d) A high percentage of impervious area correlates to a higher rate of stormwater runoff, which generates greater pollutant loadings to the City's Separate and Combined Sewer Systems, resulting in turbid water, nutrient enrichment, bacterial contamination, toxic compounds, temperature increases, and increases of trash or debris.
(e) When stormwater impacts are considered during the planning stages of a project, new development and redevelopment projects can more efficiently incorporate Post-Construction Stormwater Controls that will enhance the function and capacity of the City's Separate and Combined Sewer Systems by providing pretreatment of stormwater and protecting water quality.
(1) reducing stormwater runoff rates and volume whenever possible through Post-Construction Stormwater Controls, and ensuring that these stormwater controls are safe and properly maintained;
(2) minimizing increases in pollution caused by stormwater runoff from development that would otherwise degrade local water quality; and
(3) controlling the discharge of contaminants to the City's sewer and drainage systems through spills, dumping, or disposal.
(Added by Ord. 83-10, File No. 100102, 4/22/2010; amended by Ord. 64-16
, File No. 160155, App. 4/27/2016, Eff. 5/27/2016)