283 - Are Stormwater Managers Getting Burned: Modeling Fire Effects in the Upper Los Angeles River

The frequency and intensity of fires has drastically increased in southern California and is expected to continue increasing due to climate change and human activities in and near natural forest and foothill areas. Studies have indicated fires in the region are impacting the water quality of stormwater runoff and in receiving waters. Stormwater managers are left to consider the additional influence of fires on the water quality conditions and build resilient management strategies to sustainably progress towards water quality improvement goals. To understand the potential impacts of post-fire runoff on downstream receiving waters in the Upper Los Angeles River, this Safe, Clean Water-funded scientific study has coordinated monitoring and modeling efforts. This presentation will discuss the development of watershed models to help predict how land use and other environmental changes from fires may impact baseline pollutant loading and how climate change scenarios may further exacerbate these impacts. In addition, the watershed models are feed into best management practice (BMP) models to help plan for a more resilient management program that meets water quality objectives and supports beneficial use goals under these conditions and strategically addresses impending Total Maximum Daily Load milestones. Ranges of potential fire conditions, in terms of spatial, temporal, and severity factors, will be discussed and the relative impacts on stormwater runoff water quality in terms of magnitude and timing conditions. The study will share valuable information for stormwater managers in the regions currently impacted and in regions that will continue to be impacted by increasing fires.