Riparian is defined as "pertaining to the bank of a river". The riparian plant community is found along any stream, waterway, or river. Common plants include cottonwood, sycamore, willow, poison oak, and mule fat. Riparian plants are generally more water-thirsty than those of the other southern California plant communities.

Riparian habitat runs through other plant communities, as water flows from higher elevations through tributaries to the Santa Ana River. The narrow corridor of a stream is a valuable resource in our dry southern California climate. Streams that flow throughout the year are referred to as perennial and typically drain large acreages.

Perennial streams bring drinking water to wildlife and support plant growth all year long. These waterways are normally thick with vegetation providing food, homes, and movement corridors for wildlife.

Scholars estimate that 95% of southern California's riparian habitat has been developed or degraded. Many drainage ways have been narrowed and concrete-lined or piped and filled, rendering them useless to wildlife.

Several threatened, endangered, or sensitive species of native animals are dependent upon local riparian habitat, including the California red-legged frog, the Southwestern arroyo toad, the Southwestern pond turtle, the Least Bell's Vireo (a bird), and the Santa Ana Sucker, (a fish).

Native Plants of Riparian Areas, Wetlands, and Adjacent Habitats

There is a rich diversity of native plant species associated with riparian areas in the southern California region. RCRCD staff worked with volunteers to create a document used to educate people in our area about local native plants useful for restoration of wetlands, riparian habitats, vegetated buffers, and water quality projects. Use of local native plants helps to provide sustainable habitats, clean water, habitat for native wildlife, and reduces the threat of non-native species invasions. Click on this link for the Santa Ana River Watershed Native Plant Table.

Riparian Area Restoration

RCRCD restores critical riparian habitats, including waterways at Sycamore Canyon, Mockingbird, and Temescal Canyons, Castle View, Golden Star Creek, The Alessandro Arroyo and the Santa Ana River.

RCRCD cuts, sprays herbicide, and monitors re-growth of invasive plants, especially Arundo donax, commonly called giant reed. This invasive member of the grass family can grow to over 30 feet in height and can consume up to 5 acre-feet of water each year. It grows so densely that it degrades habitat for birds and animals. Additionally, Arundo can grow up to a foot per week, creating a serious fire hazard.

After cutting the top growth off the plant, all re-growth is sprayed with a biodegradable herbicide (specially approved for use in waterways). The glyphosate salt herbicide stops the movement of water in the plant, "drying" it up. Three to five years of quarterly spraying is needed to completely kill the root structure.

Sometimes it is hard to recognize streams in southern California. Some of our waterways appear dry during much of the year, although they may become raging torrents during the rainy season. All streams must be regarded with care. If you live in a watershed, and we all do, then you impact water quality. Learn ways to prevent the pollution of waterways in the website section: Urban Areas, Prevent Pollution or in the booklet Living on the Edge.