Swales

The grasses and plants in this vegetated bioswale intercept runoff and promote groundwater recharge. Photo credit: Sonoma County RCD

How they work

Swales are shallow channels that slow and direct water as it flows downhill. Incorporating swales into a landscape increases water retention, helping plants grow. Swales also help reduce erosion, filter pollutants, and recharge groundwater. Swales can be incorporated into existing landscapes or rain gardens, but can also be used to direct runoff to a particular location. 

vegetated Swales

Vegetated swales use plants and grasses to control runoff and filter out sediment and pollution. Incorporating a designed soil mixture of sand, loam, and clay helps further increase water retention in the swale. 

Rock-lined swales

Rock-lined swales utilize rocks, instead of plants, to convey water and encourage infiltration. Using rounded pebbles helps create a pleasing look that helps control erosion and stormwater runoff. 

Utilize at least a 2% slope with any swale to guarantee water flows in the desired direction.  

Utilize at least a 2% slope with any swale to guarantee water flows in the desired direction.  

For specific swale construction strategies, contact george@tcrcd.org or see the Sonoma County RCD's Stormwater Management Guide. The Tuolumne County Master Gardeners can also assist with swale implementation.