Post-Fire Erosion Control Project
By Andrea Pedraza, QSP and Rich Barnes, CPESC, QSD/QSP
QK Creek Fire: Post-Fire Erosion Control Project
The Creek Fire in Fresno County, California showed Mother Nature at both her worst and her best. A fire of this magnitude, the largest single California wildfire in history affecting nearly 400,000 acres and hundreds of homes, is all-encompassing — but along with remnants left behind, there is also regrowth and rebirth of the land and a glimmer of hope. The County of Fresno took the proactive initiative of tackling what was left behind and mitigating post-fire runoff and erosion caused by winter precipitation and springtime snowmelt. The project sought to address not only the resulting flooding and erosion in the wake of the fire but solutions to stabilize slopes, protect and rebuild infrastructure that had sustained damage, and safeguard natural resources including fish and wildlife in the reservoirs along the San Joaquin River watershed. QK utilized best stormwater management practices (BMPs) in the post-fire runoff control efforts. Fresno County worked alongside QK’s Qualified Stormwater Pollution Prevention practitioners (QSD/QSP) and Certified Professional in Erosion and Sediment Control (CPESC) professionals, senior civil engineers, Geographic Information Systems (GIS) mapping specialists, and land surveyors, and in coordination with the California Conservation Corps (CCC) crew to mitigate runoff hazards and protect critical infrastructure, including culverts and roads.
The likelihood that devastating wildfires will continue to decimate California is increasing. With seasonal fires now becoming the norm in this region, being prepared and educated about both the after-effects and measures to proactively defend infrastructure will take on increased importance in the effort to balance protecting the environment with the finances needed to do so.
A post-fire action plan involves:
- A thorough assessment of current conditions
- Evaluation of traffic and patterns during repair process
- Road conditions assessment to determine damage caused
- Allowance for road conditions to handle high maintenance repair vehicles
The Clock is Ticking
The Creek Fire Erosion and Sediment Control project was the first of its kind for QK and the County of Fresno. With no established processes in place and no playbook to go by, the ensuing fast-tracked discussion of options and solutions took on a new meaning for the entire team. The QK team was comprised of highly experienced and knowledgeable staff including California-registered engineers, certified SWPPP specialists, and related technical professionals ready to take on the challenge of implementing best management practices (BMPs) and were up and running quickly.
The team started by partnering with the County of Fresno to gain an understanding of the project challenges and overall goals. “Establishing roles and communication from the outset in the office and field and tracking progress while keeping the County informed on a day-to-day basis was critical to project kick-off and to maintaining momentum,” said QK Senior Associate Engineer Stephen Bahr, PE, QSD/QSP. With collaborative communication forming the foundation for the project, QK worked with the County to formulate a plan to mitigate erosion and sedimentary control issues. With the first projected snowfall just six weeks away, the project was initiated immediately. The very next day the QK team, including Stephen Bahr, PE, Andrea Pedraza, QSP and Rich Barnes, CPESC, QSD/QSP in the field collecting data and assessing the overwhelming devastation left by the Creek Fire including:
- Potential for mudslides
- Mountain drop-offs
- Steep slopes
- Sediment and runoff
- Limited and compromised road access
- Aging and under-sized culverts impeding the ability to sheet water away
The resulting assessment and data collection allowed the County to set realistic priorities for installation of BMPs within the condensed project timeline. Prioritized locations included culverts and established drainage infrastructure. Protection of these locations was a priority for the County, as drainage is crucial for preventing sediment-laden washout onto the roads. Terrain along the burn areas, steep slope, and drainage pathways was evaluated at dozens of locations along each road to establish appropriate erosion control measures entailing the selection, installation area, and type/quantity of BMP required. A list of estimated BMP quantities was generated for each location and over the course of several days, total quantities for each type of BMP was estimated for the entire project. The documentation process also allowed progress tracking and a way to measure the erosion control installations and mitigation efforts after installation.
In the Trenches
Pedraza noted the fluidity required of the project due to new innovations and techniques being used. “This project was full of moving parts and we were literally in the field from day one, directing field crews, the California Conservations Corps (CCC), FEMA, loggers, and all other players enacting various portions of the control measures. said Pedraza. “Cohesively managing all of the efforts in this high-risk area was critical and the complex execution of such a big team was so important to ensure that each step was followed in established order so that no one impeded project progress.“
Water is one of the most detrimental of nature’s resources and a key element of the project focused on re-routing water to limit damage. To address this, QK’s erosion control and stormwater pollution prevention professionals approached the logging and clearing company requesting they leave felled logs in place. Use of natural resources for water breaks is ideal as they will biodegrade over time and have no lasting negative impact on the environment. “You can’t stop water, but you can slow it down and redirect it around sensitive areas,” said Barnes.
Taking advantage of local resources and adopting a solid re-use, renew, and recycle mentality, the QK team took advantage of nature’s lumber yard for free, environmentally-sound, and accessible lumber to use in bulking up affected banks. This measure also provided habitat for wildlife and retained good soil as well as the seed layer to speed regrowth. A further benefit of leaving the logs in place negated the need for heavy equipment to be brought in to remove them, which could potentially damage roadways and access routes.
Erosion control was not the only key issue on the project — failure to address water runoff and sedimentation could result in long-term damage to 12 water systems in the region as well as to the equipment servicing them. Water quality was enhanced by reducing runoff and thereby limiting the amount of ash entering downstream bodies of water and the water system.
Fire changes soil and how it interacts with water and depending upon how long a fire burns, it also affects its properties. Assessments of each specific area allowed appropriate protective measures to contain sediments to be implemented, each one installed to operate optimally for those conditions. Best management practices put in play included:
- Use of jute mesh to allows root systems to grow and flourish while holding soil in place
- Straw wattle for water diversion, interception, and to aide in erosion control
- Sandbags for check dams in existing drainage channels to decrease the velocity of flow of water
- Riprap to interrupt the flow of sediment-bearing water into culverts
- Felled trees to create water bars and diversion dikes to control flow away from steep slopes and sensitive areas
Project Success and Lessons Learned
Staying ahead of damage caused by wildfires is a complex and dynamic science, and innovation is an engineer’s best tool. On this complex project the team was pivotal in advancing new approaches to staying ahead of the damage caused by wildfires and in developing post-fire action plans. Lessons learned include:
- Applying standard construction management approaches to this process was highly effective
- Capturing additional data in the field early on allows measures to be implemented in a timely fashion
- Understanding whole-picture impacts to the County to better anticipate their needs
- Addressing aging culverts’ ability to accommodate silty soil and size of culverts to handle increased mud flow and sediment
- Applying hydro mulch prior to rainy season
Blazing a New Trail
The project is a multiple award winner securing American Society of Civil Engineers’ Environmental Engineering Project of the Year from both the Fresno Branch and San Francisco Section.
Throughout the project lifecycle, safety of the crew and wildlife was prioritized along with preservation and respect for the natural environment. Due to the hastened schedule, BMPs were in place before the first snowfall as planned. Once the accumulated snowfall was removed, the County readily acknowledged the success of the project and that the BMPs were working as intended. Because of this work, 12 water systems affecting more than 675,000 residents were protected, and active germination was already noted.
The success of the Creek Fire Erosion and Sediment Control project has established new BMPs going forward for other cities and counties to follow. Now there is a set protocol for recovery and planning to help public agencies develop comprehensive post-fire action plans; saving money, salvaging the environment more effectively, and assisting in post-fire recovery quickly.