General Plan Update - City of Inglewood

Chapter 5 Environmental Resources
spilled or dumped, a portion evaporates, but some soaks into the ground. Once in the
soil, VOCs can be transported to the water table via percolation. This group includes a
wide range of individual contaminates; as a result the water quality standards reflect this
wide range.
Surface Water Quality
In general, changes in land use will result in changes in water quality. There is a strong
correlation between decreasing water quality and increasing development. As more land is
developed and more impervious surfaces are created, groundwater recharge is affected as
well as the volume, rate, and quality of surface water runoff. Urban runoff flows into
storm drains and in most cases flows directly to creeks, rivers, lakes, and the ocean.
Polluted runoff can have harmful effects on drinking water, recreational water, and
wildlife. The EPA National Water Quality Inventory has identified runoff from development
as one of the leading sources of water quality impairment. Urban runoff was ranked as
the sixth leading source of impairment in rivers, fourth leading source of impairment in
lakes, and the second in estuaries.
As directed by the federal Clean Water Act (CWA), the State Water Resources Control
Board (SWRCB) adopts a list of impaired water bodies (the 303(d) list) for the state of
California. The list was most recently updated in 2002 (adopted in 2003) and identifies
water quality impairments including trash, metals, pathogens, and organic pesticides.
Specifically, high levels of dissolved solids, chlorides, sulfates and heavy metals have been
recorded in the Watershed. During wet weather, measurements of copper, lead, and zinc
have regularly exceeded values set in the California Toxic Rule. These elevated
contaminate levels restrict the beneficial uses of the watershed.
Groundwater Quality
West Coast Subbasin
The TDS concentration, measured from 45 wells across the West Coast Basin, ranges
from 170 to 5,510 mg/L, with an average concentration of 720 mg/L. Additionally,
approximately 45 wells were analyzed for inorganic and radiological contaminants,
nitrates, pesticides, and VOCs. The concentration of inorganic contaminants in 30 wells
exceeded the maximum contaminant level. The MCL for VOCs was not exceeded at any
of the wells in this subbasin. Radiological contaminants were above the maximum
contaminant level in one well and nitrate concentrations were not above the MCL in any
wells.
5.2-6
City of Inglewood General Plan Update Technical Background Report