Representative photo — not the project site.
Post-fire road drainage
Butte Creek Camp Fire Post-Fire Recovery: Centerville Road Stream Crossings
Surveys, culvert sizing and replacement plans for 18 stream crossings along 2.4 miles of unpaved road in the Camp Fire burn area.
The project
The Butte Creek Camp Fire Post-Fire Recovery Project is a Butte County Resource Conservation District effort to reduce sediment reaching Butte Creek by improving road drainage, stream function and water quality along 2.4 miles of Centerville Road.
American Engineering provided the topographic surveys, culvert sizing calculations and culvert replacement plans for a watershed consulting firm, on a project sponsored by the Butte County Resource Conservation District.
Centerville Road links Chico and the community of Magalia through the Butte Creek watershed. Near the community of Irish Town, where the road is unpaved, it crosses a string of unnamed tributaries of Butte Creek, most of them carried under the road in culverts.
The 2018 Camp Fire burned 153,336 acres of Butte County. Fire strips vegetation and exposes soil, so runoff, sediment and debris all rise in the storms that follow. The district's page for its Post-Camp Fire Dixie Road project, on a different road, reports that a series of storms in the burn area plugged multiple culverted stream crossings. A plugged culvert can send water over the road and wash its fill into the creek below.
The stakes are high on this creek. Butte Creek is one of only three Central Valley streams with a self-sustaining population of spring-run Chinook salmon, a species listed as threatened under the state and federal Endangered Species Acts. When the Camp Fire broke out, young spring-run Chinook were just hatching, and sediment and toxic ash threatened to smother them in the first big rain.
Scope
Our scope
American Engineering's scope ran from topographic surveys to as-built plans. The work, grouped by phase:
Survey the sites
- Topographic surveys of 18 stream crossing sites along the 2.4‑mile segment
The measured base that topographic surveying provides for every crossing design.
Size the culverts
- Culvert sizing calculations
Estimating the flow a tributary must pass and checking that a replacement culvert can carry it. See stormwater calculations.
Prepare plans and the estimate
- Culvert replacement improvement plans for each stream crossing site
- Erosion control plans
- Engineer's estimate of probable cost
The construction documents: improvement plans and erosion control plans.
Inspect and coordinate
- Site inspections
- Coordination between the contractor and public agencies
Document the as-built work
- As-built plans
Drawings that record what was actually built.
Technical highlights
How the work fits together
Two illustrative diagrams: how the crossings relate to the creek, and what a typical post-fire culvert upgrade changes.
Eighteen crossings, one creek
Each crossing carries a tributary that ends in Butte Creek, so one failed culvert can send road fill down to the creek. American Engineering's scope covered 18 crossing sites: a topographic survey and a culvert replacement improvement plan for each, backed by culvert sizing calculations and erosion control plans.
18 crossings along one road
Illustrative diagram — not to scale
- A stream crossing: a culvert carries an unnamed tributary under the road. American Engineering surveyed 18 crossing sites and prepared a culvert replacement plan for each.
- Burned slopes shed more runoff, sediment and debris in the storms after a fire.
- An undersized or plugged culvert (ringed in red) can overtop and wash out, sending road fill down its tributary.
- Every tributary drains to Butte Creek, a spring-run Chinook salmon stream.
What a typical crossing upgrade changes
Post-fire crossing upgrades typically replace an undersized culvert with a larger one sized for a large design storm plus the extra sediment and woody debris that burned slopes shed, and set it at the natural grade and alignment of the channel. Trash racks, rock at the outlet and armored fill help a crossing ride out the storms that follow.
A typical crossing, before and after an upgrade (profile along the stream)
Illustrative diagram — not to scale
Before
- Undersized culvert set above the streambed, with a perched outlet that drops onto the bed.
- Post-fire sediment, ash and woody debris bury and block the inlet.
- Water ponds behind the fill and overtops the road.
- Overflow erodes the fill (a washout) and sends sediment downstream.
After
- Larger culvert sized for the design flow plus post-fire sediment and debris. At that flow the headwater depth (HW) stays below the culvert's diameter (D), leaving room for floating debris to pass.
- Laid at the natural grade and alignment of the streambed.
- A single-post trash rack catches floating debris before it reaches the inlet.
- Rock at the outlet and on the fill face resists scour.
Engineering considerations on burned-watershed crossings
- Design flows for small streams
Small tributaries rarely have stream gauges, so engineers estimate peak flows from watershed area, soils and published rainfall data, with allowance for runoff from burned slopes.
- Sediment and debris
A culvert large enough for clean water can still plug with gravel, ash and branches, so sizing and inlet protection allow for the debris burned slopes shed.
- Fish passage
The district's CEQA notice states that culvert replacement work will be consistent with current California Department of Fish and Wildlife (CDFW) and NOAA Fisheries (NMFS) fish-passage guidelines.
- Dry-season work and winter readiness
In-stream work is generally limited to the dry season, and disturbed fill slopes need erosion control in place before winter storms; erosion control plans define those measures.
Permits & funding
Regulatory and funding context
Public records show the approvals and funding behind the district's project. They describe the overall project, not American Engineering's scope.
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CEQA · 14 CCR §15302
Exempt as replacement of existing structures
The district filed a CEQA notice of exemption in March 2024, and the Central Valley Regional Water Quality Control Board filed its own in July 2024. Both cite the replacement-or-reconstruction exemption; the Water Board's notice describes new structures in the same footprint, with "substantially the same purpose and capacity" as those replaced.
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Fish & Game Code §1602
Streambed alteration agreement
Substantially changing the bed, channel or bank of a stream requires notifying CDFW first. CDFW executed a streambed alteration agreement (notification BUT-48731-R2) with the district as applicant, covering culvert work on unnamed tributaries of Butte Creek along Centerville Road near Irish Town, and filed its CEQA notice in August 2025.
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Work window · fish passage
Dry-season work and biological protection
The district's notice confines work in stream channels to June 1 through October 31, or until the first significant rain, and not within 12 hours after more than half an inch of rain; work outside that window needs CDFW approval week by week, depending on the weather forecast. Culvert replacement work is to be consistent with current CDFW and NMFS fish-passage guidelines, and a qualified biologist provides a site-specific plan to protect aquatic life.
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Clean Water Act §319
Nonpoint source grant funding
The State Water Board placed the project, with the district as applicant, on its 2021 Nonpoint Source Grant Program fundable list. The program passes U.S. EPA Clean Water Act §319 grants to projects that cut polluted runoff, including upgrades to failing dirt roads that reduce erosion and sedimentation.
Permit conditions vary by site and agency. On stream crossing projects, permits typically set the in-stream work window, dewatering method and monitoring, so design and construction schedules are planned around them.
Services used on this project
Sources
Public records and agency pages behind the project context above. The scope section describes American Engineering's own work.
- Butte Creek Camp Fire Post-Fire Project, Notice of Exemption (March 22, 2024) (Butte County Resource Conservation District, via CEQAnet)
- Butte Creek Camp Fire Post-Fire Recovery Project, Notice of Exemption (July 2, 2024) (Central Valley Regional Water Quality Control Board, via CEQAnet)
- Streambed Alteration Agreement BUT-48731-R2, Notice of Exemption (August 18, 2025) (California Department of Fish and Wildlife, via CEQAnet)
- Camp Fire incident page (CAL FIRE)
- Post-Fire Recovery (Burned Area Emergency Response) (National Interagency Fire Center)
- Roads and Trails projects: Post-Camp Fire Dixie Road Sediment Reduction (Butte County Resource Conservation District)
- Butte Creek spring-run Chinook salmon (California Department of Fish and Wildlife)
- Camp Fire Response: Butte Creek Canyon (Butte County Resource Conservation District)
- 2021 Nonpoint Source Grant Program Fundable Project List (PDF) (State Water Resources Control Board)
- Nonpoint Source (319(h)) Grant Program (State Water Resources Control Board)
- Fish and Game Code §1602 (California Legislative Information)
Last reviewed .