WATER QUALITY STUDY OUTLINES
IMPROVEMENT PLAN FOR ALISO CREEK WATERSHED
FOR IMMEDIATE RELEASE
Contacts: Larry Paul
County of Orange
Public Facilities &
Tops the List of Recommended Management Strategies
Santa Ana, CA (July
28, 2000) -- A comprehensive list of recommendations ranging
from programs to educate the public about water quality
and urban runoff to retrofitting existing drainage systems
are among the management strategies proposed by the County
to improve water quality within the Aliso Creek Watershed.
The recommendations are based on the findings of a two-year
$152,000 study of the Aliso Creek area, a watershed that
extends southwest from Portola Hills through Lake Forest,
Mission Viejo, Laguna Hills, Laguna Niguel, Aliso Viejo
and Laguna Beach.
The study, $114,000 of which was financed by a grant from
the state, examined conditions within the 34.6-square-mile
watershed and describes a creek -- and its associated
features -- that is characterized by elevated bacteria
counts, unstable aquatic life and ecological stress. High
water temperatures were also noted downstream of developed
portions of the watershed and may be a contributor to
reduced plant life and animal species.
More than a dozen short- and long-term strategies for
water-quality improvement are ranked within the study's
recommendations and are proposed to be used by the County
and affected cities in planning their future water quality
efforts to restore the creek and protect the watershed's
Study results and findings will also be incorporated into
a larger watershed management study of Aliso Creek now
being prepared by the U.S. Army Corps of Engineers.
"Of the management strategies identified, public
education is of the highest priority and can provide the
broadest and most immediate impact," said Vicki Wilson,
director of the Public Facilities & Resources Department.
"The County has taken several steps to improve water
quality in the Aliso Creek area, including diverting urban
runoff to a sewage-treatment plant. But we can only be
successful in our efforts with the support of those who
live in the watershed area as well as those who visit
the local parks. Educating the public on the poor condition
of the watershed and the steps they can take to help improve
water quality is critical to our overall effort."
Other recommendations, including such long-term and costly
approaches as constructing an on-site biofiltration facility
and building one or more water-quality wetland areas in
the lower Aliso Creek watershed, are also listed as management
strategies in this scientific study.
The County began the Aliso Creek Water Quality Planning
Study in late 1997 by examining existing resource materials
and developing extensive maps of the watershed. The maps
delineate the major tributaries, sub-basins and physical
features in the watershed, general land uses, land ownership
and the major water and sewer infrastructure in the area,
all of which provided a base for experts to begin their
An assessment of aquatic life at four sites in Aliso Creek
and two in Sulfur Creek were also performed and all test-area
habitats were found to be biologically unstable. Studies
also showed evidence of ecological stress.
Elevated bacteria concentrations originating from several
locations along the creek were also noted. In addition,
higher water temperatures, like those found in more developed
areas, were logged along Aliso Creek and may have a negative
influence on water quality and creek biology. One of the
recommended strategies is to restore shaded areas along
As part of the study, the County also performed a recreational-use
analysis and determined water quality improvements could
possibly generate a benefit valued at $600,000 annually
at the three major recreational parks within the watershed,
Laguna Niguel Regional Park, Aliso and Wood Canyons Regional
Park, and Aliso Beach Park.
Representatives from impacted cities, local and state
agencies, and environmentalists participated in the two-year
effort. As part of this outreach, a technical advisory
committee was formed where results of the water-quality
studies were discussed and input solicited on study direction.
The Aliso Creek Watershed has been identified by the San
Diego Regional Water Quality Control Board as a target
watershed for priority water-quality protection efforts,
with the lower mile of the creek designated as "impaired"
under the federal Clean Water Act due to elevated bacteria
The Aliso Creek Watershed effort is the first of its kind
in the County. Similar watershed restoration studies are
underway for the San Juan Creek Watershed and the San
Diego Creek/Newport Bay Watershed.