Chico Mud Creek Drainage District (CSA 24) - City of Chico

Source: Butte County LAFCO, 2005.
A Division of
FIGURE 4.3-2C
Chico Mud Creek Drainage District (CSA 24)
D51061.00
NORTH
Chico MSR

Source: Butte County LAFCO, 2005.
A Division of
FIGURE 4.3-2D
Shasta Union Drainage District (CSA 25)
D50961-00
NORTH
SCALE IN
Chico MSR

Municipal Service Review
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4.3 Storm Drainage
Map (FIRM) for unincorporated Butte County shows Sacramento River overflow inundating an area
about two miles east of the river boundaries. The volume of water within this two‐mile backwater area
would be expected to increase over time with additional urban runoff associated with growth, as well as
from natural drainage. 10
Capacities of channels in the western portion of the City are also limited, and potential flood flows are
believed to be higher than recorded historical occurrences. The FIRM also shows floodwater flowing out
of the Big Chico Creek Channel near the western edge of the City. Inadequate channel capacity
exacerbates the flooding potential near the Sacramento River. Flood control projects on Little Chico
Creek, Big Chico Creek, and Lindo Channel have helped reduce the amount of runoff that flows through
the City, reducing potential flooding problems.
The Department of Water Resources is responsible for maintenance of the Sycamore‐Mud Creek‐Sandy
Gulch channels. The Department of Water Resources maintains the Little Chico Creek Diversion and
Butte Creek levees with funding through State Maintenance Area 5. The City of Chico and Department
of Water Resources share responsibility for maintenance of the Little Chico Creek channel. By agreement
with the Department of Water Resources, Butte County only maintains the Sycamore‐Mud Creek‐Sandy
Gulch levees and structures. Funding for this maintenance is provided by CSA 24. Butte County does
not maintain flood control channels. The M&T diversion from Butte Creek to Comanche Creek is a
private facility and is maintained and operated by the M&T Ranch. 11
Determination 4.3-4
Urban development along waterways and encroachment on floodplains creates flooding problems in the
City and in the agricultural area west of the City. Storm drainage system improvements identified in the
Storm Drainage Master Plan (SDMP) address these flooding issues.
� Funding and Fees
The majority of the storm drainage collection system located within City limits is operated and
maintained by the City General Services Department, O&M Division. Maintenance of facilities within
the City is funded primarily from the General Fund. Storm drainage collection facilities located outside
the City limits are typically maintained by the County Department of Public Works. Flood control
improvements within the City are maintained primarily by the County. Funding for storm drainage
facilities and infrastructure typically depends on the location of the structure. Funding for CSAs No. 22,
23, and 25 is only for the operation and maintenance of the facilities constructed as part of the original
assessment districts. CSA funding does not provide for maintenance of new, primarily subdivision‐
related storm drainage facilities that connect to the original assessment district facilities.
10 City of Chico, General Plan, November 1994, Updated September 1999.
11 City of Chico, Storm Drainage Master Plan Environmental Impact Report, October 2000.
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Chapter 4. Infrastructure Needs and Deficiencies
The City levies a Storm Drain Development Impact Fee (Fund 309) authorized by Chapter 3.85.405 of the
Chico Municipal Code. The purpose of the fee is to provide funding for the construction and expansion
of the City’s storm drain system to accommodate the needs of projected new growth. It also provides
funding as indicated in the “2000 City of Chico Storm Drainage Master Plan Integrated Document” for
peak attenuation facilities (storm water detained in detention ponds), water quality facilities, and data
collection facilities. 12
The maintenance and repair of diversion structures, levees, and access roads that were constructed as
part of the U.S. Army Corps of Engineers Big Chico Creek, Sycamore Creek, Mud Creek, Sandy Gulch,
and Lindo Channel improvement projects are funded by CSA No. 24, administered by the County
Department of Public Works. Open ditches and other facilities in CSAs 22, 23, and 25 are also
maintained by the County with funds generated within the CSAs.
4.3.2 Plans and Regulatory Requirements
� National Pollutant Discharge Elimination System
The National Pollutant Discharge Elimination System (NPDES) permit system was established in the
Clean Water Act (CWA) to regulate municipal and industrial discharge to surface waters of the U.S.
Each NPDES permit contains limits on allowable concentrations and mass emissions of pollutants
contained in the discharge. The permit would require the municipal authority to evaluate the quality of
its stormwater discharge and receiving waters, identify areas of pollutant loading, and implement a
program of BMPs to control pollutant discharges to the maximum extent practicable. It is within the
existing authority of the CVRWQCB to issue a NPDES permit for any stormwater outfall that discharges
to the waters in the region.
Discharges from municipal separate storm sewer systems (“MS4s”) in urbanized areas are regulated
because of concern over the high concentration of pollutants found in those discharges. Phase I of the
stormwater program, which addresses runoff from these sources, began in 1990. Additional federal
legislation, referred to as the Storm Water Phase II program, has been promulgated under the NPDES
program to include small municipalities with populations of 1,000 to 100,000. The Phase II program
expands the existing Phase I program by requiring additional owners and operators of small MS4s in
urbanized areas (and construction sites), through the use of NPDES permits, to implement programs and
practices to control polluted stormwater runoff.
The City has been identified as one that is required to comply with NPDES Phase II permitting because it
has been identified as an “Urbanized Area” by the Bureau of Census. Both the City and County are part
of the NPDES Phase II permit requirements for the Chico Urbanized Area. Both jurisdictions have
permits and have been working cooperatively to comply with State and federal requirements. In the
City, the County of Butte, City of Chico, Chico Unified School District, and California State University,
Chico are required to develop a storm water management program that implements six minimum
measures focusing on a Best Management Practice (BMP) approach. The BMPs chosen by the operators
of the MS4s should be designed to reduce pollutants in urban storm water compared to existing levels in
12 City of Chico, Department of Public Works, 2004‐05 Updates of Development Impact Fees Analysis and Recommendations (Nexus Study),
November 2, 2004, p. vi.
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4.3 Storm Drainage
a cost‐effective manner. BMPs include public education, treatment practices, operating procedures, and
practices to control site runoff, spillage, or leaks.
NPDES permits are issued for five‐year terms and generally follow a progressive pattern.
To meet NPDES Phase II permit requirements, the City submitted a Storm Water Management Program
(SWMP) along with a MS4 NPDES Storm Water Permit Application to the CVRWQCB to obtain a permit.
The SWMP presents strategies, goals, priorities, and management activities for years 2003 to 2008 to
prevent pollutants from entering the storm drainage system. The objectives of the SWMP are to provide
guidance to the public and businesses, and act as a coordinating entity towards a cohesive storm water
program. An NPDES Phase II SWMP must meet six minimum controls, use best management practices
(BMPs) to the maximum extent practicable, and achieve measurable goals. In the first five years of the
program, the focus is on establishing a program customized to local conditions using the following six
minimum measures:
1. Public education and outreach;
2. Public participation/involvement;
3. Construction site runoff control;
4. Post‐construction runoff control;
5. Pollution prevention/good housekeeping; and
6. Program Evaluation Activities.
Future permits will be issued based on using the knowledge gained during the first five‐year permitting
and putting it to work on improving water quality incrementally over time.
� Federal Emergency Management Agency
The Federal Emergency Management Agency (FEMA) administers the National Flood Insurance
Program (NFIP) to provide subsidized flood insurance to communities complying with FEMA
regulations that limit developments in floodplains. FEMA is the main federal government agency contact
during natural disasters and publishes Flood Insurance Rate Maps (FIRM), which identify the extent of
flood potential in flood prone communities based on a 100‐year flood (or base flood) event.
The NFIP regulations permit development within special flood hazard zones provided that residential
structures are raised above the base flood elevation of a 100‐year flood event. Non‐residential structures
are required either to provide flood proofing construction techniques for that portion of structures below
the 100‐year flood elevation or to elevate above the 100‐year flood elevation. The regulations also apply
to substantial improvements of existing structures.
� City of Chico General Plan Policies
The General Plan encourages use of natural drainage techniques and provides policies to ensure
provision of adequate drainage facilities. The three‐pronged strategy governing the policies that follow
includes:
■ Use of natural drainage and reduced storm water flow techniques where feasible;
■ Incorporation of storm‐water detention facilities for projects draining into Little Chico and
Comanche Creeks; and
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Chapter 4. Infrastructure Needs and Deficiencies
4.3-18
■ Provision of filtration system for all drainages in the City.
The Parks and Public Services, Open Space, and Safety elements of the City of Chico General Plan
contain guiding principles, goals, and policies related to drainage. Issues addressed include funding,
maintenance, runoff, and flood control. Applicable key storm drainage policy statements from the
General Plan are presented below:
Parks and Public Services Element
PP‐Implementation‐37: Continue exploring alternatives to stormwater collection methods, including the
use of detention/retention basins and the feasibility of a ʺno net runoffʺ concept for the entire urban area.
PP‐Implementation‐38: Use porous materials (e.g. porous asphalt, modular paving, gravel, lattice
concrete blocks and porous bricks) for outdoor spaces, paving, and sidewalks, where feasible.
PP‐Implementation‐39: Establish storm‐water run‐off reduction standards for projects larger than five
acres and incentives for ʺzero‐netʺ stormwater runoff, such as reduced storm drainage impact fees.
PP‐Implementation‐40: Delineate urban areas draining to Little Chico and Comanche creeks, and require
storm‐water detention for all projects draining to these creeks. Require no net increase in peak
stormwater runoff.
PP‐Implementation‐41: Explore the feasibility of an area‐wide rate structure to fund storm water
drainage and ongoing maintenance. Require all new development to pay this fee as a condition of
project approval.
PP‐Implementation‐42: Ensure that new development has a minimal impact on natural drainage
channels and flow capacity.
PP‐Implementation‐43: Continue requiring project proponents to provide plans for erosion and
sedimentation control from their sites during construction.
PP‐Implementation‐44: Undertake maintenance efforts, in cooperation with the County, to ensure that
channels that convey surface drainage are not blocked.
PP‐Implementation‐62: Use resource‐based standards for transportation facilities, parks, water,
wastewater, and drainage facilities and police and fire service established in Table 5.6‐1 as a basis for
decision on applications for major development projects.
PP‐Implementation‐63: Continue to require that new development pay its fair share of costs associated
with providing streets and facilities for police and fire protection, parks, wastewater treatment, and
drainage.
Open Space Element
OS‐Guiding‐12: Where feasible, given flood control requirements, maintain the natural condition of
waterways and flood plains and protect watersheds to ensure adequate
groundwater recharge and water quality.
OS‐Guiding‐15: Preserve and enhance Chicoʹs creeks and the riparian corridors adjacent to them as open
space corridors for the visual amenity, drainage, fisheries, wildlife
habitats, flood control and water quality value.
Safety Element
S‐Guiding‐1: Minimize threat to life and property from flooding and dam inundation.
S‐Implementation‐1: As part of project review, ensure that structures subject to the 100‐year flood
provide adequate protection from flood hazards.
S‐Implementation‐2: When considering areas for future urban expansion ensure that impacts of flooding
are adequately analyzed.
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4.3 Storm Drainage
S‐Implementation‐3: In designing flood control facilities, consider the need to protect anadromous
fisheries and allow for adequate water passage to ensure the survival of downstream riparian
ecosystems.
In accordance with the requirements of the General Plan, a Best Practices Manual (BPM) and Best
Practices Technical Manual (BPTM) have been prepared by the City. These manuals are a compilation of
existing City guidelines, codes, policies, programs, and standardized mitigation measures pertaining to
General Plan policies that are best implemented via the documents included in these manuals (e.g., storm
drainage systems). The manuals also incorporate the regulatory standards of other federal, State, and
regional agencies, as appropriate. Regulations, guidelines, and standards specific to storm drainage
include General Plan policies, Standard Mitigation and Monitoring Program, Best Management Practices
(Water Quality), Grading Standards, Erosion Control Standardized Notes, Pertinent CalTrans Contract
Specifications, and CVRWQB Construction Stormwater Permit. 13
� City of Chico Storm Drainage Master Plan
The City of Chico has adopted a Storm Drainage Master Plan (SDMP) in September 2000 that identifies
the public storm drain improvements necessary to serve a major portion of the City at buildout. The
specific objectives of the SDMP are to:
■ Develop a consistent set of planning criteria;
■ Update and modify existing storm drainage studies;
■ Prepare a preliminary storm drain master plan for all pipes larger than 18 inches in diameter;
■ Develop planning level cost estimates for required improvements;
■ Identify topographic or other data requirements needed for future drainage planning;
■ Collect more precise definition of appropriate design high water elevations in the creeks;
■ Implement a computer model of the system;
■ Provide peak flow attenuation in Comanche and Little Chico Creeks;
■ Provide channel stabilization in all waterways in the urban area; and
■ Implement BMPs to minimize water quality impacts throughout the City.
The SDMP identifies specific projects to improve existing storm drainage and to provide drainage
facilities for future development. The drainage facilities would include replacement of existing pipes,
placement of new pipes, installation of pump stations, construction of peak flow attenuation facilities
(detention basins), bank stabilization facilities, stormwater quality facilities, and design and data
collection programs. In particular, peak attenuation facilities would be constructed in the Comanche
Creek and Little Chico Creek Urban Drainage Basins. The specific size and design of individual facilities
would vary. Each project would adhere to standards, performance criteria, and design criteria consistent
with the SDMP, the SDMP Addendum, and the General Plan, as adopted by the City Council and as
amended to reflect advances in policy, technology, or engineering practice. 14
13 City of Chico, Storm Drain Master Plan and Addendum, Executive Summary, 1997, p. 4.
14 City of Chico, Storm Drainage Master Plan Environmental Impact Report, October 2000.
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Chapter 4. Infrastructure Needs and Deficiencies
Municipal Code
Title 15 of the City of Chico Municipal Code requires all rainwater, storm drainage, or other water which
is not required to be conveyed to the City’s sanitary sewer system or private sewage disposal system to
be conveyed to the City’s storm drainage system or drainage channel. If it is determined by the Director
of Engineering that storm drainage cannot be conveyed to the City’s system, the Director may authorize
a temporary leachfield‐type storm drainage system.
4.3.3 Anticipated Demand and Planned Improvements
Planned and funded improvements to the City’s stormwater drainage system are contained in the City’s
2005/06 CIP. Design and construction of storm drainage facilities are planned at Elm Street between 21 st
and 22 nd Streets and at Stilson Canyon and Humboldt Roads. Reconstruction of East 5 th Avenue will
include improvements to the existing storm drainage system from The Esplanade to SR 99.
� Northwest Chico Specific Plan (NCSP)
An existing storm drainage system in the NCSP conveys storm water from the Plan Area and
contributing offsite areas into Mud and Sycamore Creeks. The existing Shasta Union Drainage
Assessment District (SUDAD) Channel is the primary drainage channel through which stormwater
runoff from the Plan Area travels to Mud Creek. The SUDAD system, designed in 1964, to primarily
serve rural uses is comprised of several open lined and unlined channels that function as a gravity
system. The existing SUDAD system is owned, operated, and maintained by Butte County and is
anticipated to remain under the County’s jurisdiction after development of the NCSP.
The NCSP EIR analyzed two alternative drainage systems to offset the impacts of increased runoff
volume and peak flow volumes. Alternative 1 would use an off‐site parcel, adjacent to the southwest
corner of the Plan Area and Mud Creek, to accommodate drainage detention. This area would also
function as a wetland restoration project, with water quality treatment features. This alternative would
also include a second drainage detention facility west of Highway 99 that would serve as a neighborhood
park with the capacity to provide 18 acre‐feet of water storage. Pipes would range from 30 inches to 66
inches and would be designed to carry the flow from a 10‐year event.
The second alternative would have three detention facilities located on the west side of Highway 99.
Alternative 2 includes the same drainage facility (detention basin) that would serve as a neighborhood
park and provide 18 acre‐feet of water storage as Alternative 1. Alternative 2 also includes a detention
basin in a park area along Mud Creek which would provide 2.5 acre‐feet of storage along with another
detention facility to the south that would provide another approximately 9 acre‐feet of storage. A new
storm drain parallel to Mud Creek would carry outflows from these detention basins as well as runoff
generated from most development west of Powerline Drive. The storm drain system would consist of
pipes of varying sizes, from 30 to 66 inches, and would drain by gravity.
Both Alternative 1 and Alternative 2 drainage plans would result in some minor flooding; however, there
would be an improvement over existing conditions. The NCSP EIR concluded Alternative 1 was the
preferred drainage plan.
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Determination 4.3-5
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4.3 Storm Drainage
The Northwest Chico Specific Plan includes stormwater drainage facilities that would accommodate
increased runoff volume and peak flow volumes from that project.
� Funding and Fees
The City and County would continue to operate, maintain, and fund the facilities for which they are
currently responsible. Maintenance and operation funding comes from the General Fund and CSAs.
As a result of new development occurring on residential and nonresidential property located within the
City, the City is required to make substantial improvements to the City’s storm drainage system. The
City’s Five‐Year Capital Improvement Program (CIP) identifies $3.1 million in improvements from the
Storm Drainage Facility fund (Fund 309) across four projects. The two storm drain facilities projects that
have funding are the Stilson Canyon/Humboldt Road Storm Drain and the 22 nd Street and Elm Street
Storm Drain. A list of planned storm drainage system improvement expenditures from FY 2005/06
through FY 2009/10 are summarized in Table 4.3‐1.
Table 4.3-1 Summary of CIP Expenditures for Storm Drainage System Improvements
Fiscal Year
Project Description Fund 2005/06 2006/07 2007/08 2008/09 2009/10 TOTAL
Annual Nexus Study Update 309 8,348 8,348 8,348 8,348 8,348 41,740
Stilson Canyon/Humboldt Rd Storm Drain 309 70,528 0 0 0 0 70,528
22nd St and Elm St Storm Drain 309 97,440 0 0 0 0 97,440
E. 5th Ave Reconstruction 309 69,600 0 2,850,000 0 0 2,919,600
TOTAL 245,916 8,348 2,858,348 8,348 8,348 3,129,308
Determination 4.3-6
Maintenance of storm drainage facilities within the City is funded primarily from the General Fund. The
CIP identifies $3.1 million in improvements to the City’s storm drainage system over the course of five
years from 2005/2006 to 2009/2010.
4.3.4 Summary of Written Determinations
4.3‐1 Stormwater runoff in the City is collected and conveyed by storm drainage systems operated and
maintained by the City and County. Existing storm drainage system improvements are effectively
managed and operate with sufficient capacity to accommodate flows. Planned improvements to ensure
future flows are effectively managed and operated have been identified in the SDMP.
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Chapter 4. Infrastructure Needs and Deficiencies
4.3‐2 The City has prepared and implemented a Storm Water Management Program (SWMP) to minimize
runoff and prevent pollutants from entering the storm drainage system.
4.3‐3 Four County Service Areas (CSAs) to facilitate the provision and funding of necessary drainage facilities
for portions of both incorporated and unincorporated areas. Two of the CSAs in the City’s SOI (CSA 22
and 23) will be fully within the City limits following current annexation activities. Approximately 65
percent of CSA 25 will be in the City limits. A mechanism for transfer of existing funding for
maintenance of these CSAs is still being developed. Approximately one third of the CSA 24 is outside the
City SOI, and the timeline and mechanism detachment/dissolution has not yet been determined.
4.3‐4 Urban development along waterways and encroachment on floodplains creates flooding problems in the
City and in the agricultural area west of the City. Storm drainage system improvements identified in the
Storm Drainage Master Plan (SDMP) address these flooding issues.
4.3‐5 The Northwest Chico Specific Plan includes stormwater drainage facilities that would accommodate
increased runoff volume and peak flow volumes from that project.
4.3‐6 Maintenance of storm drainage facilities within the City is funded primarily from the General Fund. The
CIP identifies $3.1 million in improvements to the City’s storm drainage system over the course of five
years from 2005/2006 to 2009/2010.
4.3-22
City of Chico