Blanco Drain Natural Treatment System
Client
Resource Conservation District of Monterey County
Project Categories
Tags
valveNature-Based Water TreatmentHydology/Hydraulics
Client
Resource Conservation District of Monterey County
Project Categories
Tags
valveNature-Based Water TreatmentHydology/HydraulicsThe Salinas Valley is a vital agricultural hub, producing 70% of the nation’s lettuce and other crops. However, intensive farming has led to high nitrogen runoff, which flows into local waterways through the Blanco Drain and contributes to a growing “dead zone” in Monterey Bay. To combat this, FlowWest partnered with the Resource Conservation District of Monterey County to develop a nature-based solution that reduces agricultural pollution while supporting sustainable farming practices.
A major contributor to nitrogen pollution is the Blanco Drain, an agricultural drainage channel that collects runoff from lower valley farms. To address this, FlowWest designed and implemented a microbial denitrifying bioreactor adjacent to the drain. This system serves as a scalable solution that individual farms can adopt to treat nitrogen at its source, reducing the overall pollutant load before it reaches sensitive waterways.
Constructed in 2022, the bioreactor features a groundbreaking vertical flow design, eliminating common inefficiencies such as short-circuiting seen in other systems. Initial performance results exceeded expectations, with the system achieving a 99% nitrate removal efficiency—reducing inflow concentrations from 49 mg/L to just 0.5 mg/L during the summer of 2022. This success demonstrates the potential for broader application across the Salinas Valley, providing a sustainable, cost-effective approach to improving water quality and protecting Monterey Bay’s ecosystem.
