Stormwater planning in the US is typically concerned with improving drainage in small urban areas, via low-impact development. However, in Yolo County, California, where most of the landscape is farm fields and native oak savannah, SEI played a different, complementary role by evaluating large landscape opportunities for controlling and re-deploying winter runoff.
Through field visits, literature review, interviews and several modeling tools, SEI sought to find the most promising solutions that both reduced the impacts of frequent low-intensity flooding in western Yolo County and increased groundwater recharge from excess winter runoff from those flood events.
In the process, SEI evaluated the opportunities and constraints to recharging groundwater from unlined canals in the winter; the flow contributions of old intermittent stream channels (called sloughs) further upstream; and ways to mitigate runoff from farm fields that frequently cause road flooding. SEI also helped collect a community-driven catalog of flooding in the small town of Madison. A list of recommendations was shared with the Yolo County Flood Control and Water Conservation District (YCFCWCD), and other agencies involved in flood management in the county.