Our Watershed
Everything Flows Together
The San Antonio River Basin connects communities, neighborhoods, creeks, wildlife, and people across our region. What happens upstream affects what happens downstream—and every one of us has a role in protecting these waterways.
What is a Watershed?
A River Basin is an area drained by a river and all of its tributaries.
A watershed is an area of land bounded by ridges or higher-elevation areas where all flowing surface water converges to a single point. It is also an area of land where rainwater and runoff drain into a common waterway. Every creek, stream, river, and drainage area is part of a larger system.
That means the choices we make on land can affect the water downstream.
For River Aid San Antonio, protecting our waterways means looking at the whole watershed—not just one stretch of river.
One River.
Many Watersheds.
The San Antonio River Basis is made up of interconnected waterways that flow through communities across the region.
River Aid San Antonio recognizes six watershed areas as part of our work:
Explore Your Watershed
Every watershed has its own waterways, communities, challenges, and opportunities for stewardship. Explore the areas that make up the San Antonio River Basin.
Upper San Antonio River
The upper San Antonio River watershed is characterized by heavy urban and suburban growth in northern San Antonio and surrounding communities. Formerly spring-fed creeks have seen reductions in spring flow because of drought an increased pumping to provide water for a growing reason. Still, these creeks can often flood quickly during rains, when deluges also wash waves of trash into our rivers.
West Side Creeks
San Antonio’s West Side Creeks flow through the inner city, west and northwest of downtown, an regularly hit with severe flooding before federal flood control projects were built in the mid-20th Century. While they helped prevent the worst floods, these projects also turned formerly naturally shaped creeks into trapezoid-shaped channels. Recently, local governments have expanded a trail network on the West Side Creeks, allowing volunteers to access trash that accumulates in these new trail areas.
Leon Creek
Leon Creek begins near Leon Springs in northwestern Bexar County and flows 36 miles southward to its confluence with the Medina River. It passes through suburban and commercial areas in western San Antonio and flows alongside Joint Base San Antonio-Lackland. Some parts of Leon Creek had a history of industrial pollution, and one area of the creek is subject to an advisory warning people not to eat fish because of a type of toxins called PCBs. However, the Leon Creek Greenway is also a popular recreation destination for cyclists, mountain bikers, runners, drawn to its paved and off-road trail networks.
Salado Creek
Salado Creek begins in Fair Oaks Ranch, in far northern Bexar County. The mostly dry creek bed proceeds south through the Stone Oak area, with the Salado Creek Greenway beginning at the junction with Leon Creek Greenway at Eisenhauer Park. The creek and greenway pass a diverse variety of open space in northern, eastern, and southeastern San Antonio, including Phil Hardberger, McAlliste, and Southside Lions Parks. The creek also cuts through Fort Sam Houston northeast of downtown. It eventually joins the San Antonio River near Trueheart Ranch Nature Park in southeastern Bexar County. Many areas of the Salado Creek have lush banks and more natural surroundings than other urban creeks in San Antonio. However, trash often accumulates in these areas, many of which have trail access for the first time.
Medina River
The Medina River is a major tributary to the San Antonio River, beginning from Hill Country streams in northwestern Bandera County and backing up behind a dam to form Medina Lake. From there, it flows through the city of Castroville and rural areas to San Antonio’s southwest. Medina River Natural Area, one of the city’s largest parks, is located along its banks. Though not as urbanized as its sister river, the San Antonio, the Medina River experiences pollution from runoff from agricultural operations and often has relatively high levels of algae-forming nutrients.
Lower San Antonio River
The lower San Antonio River watershed makes up most of the river’s 240-mile path. It flows through areas with a storied ranching history, as well as the oil and gas fields of the Eagle Ford Shale. It passes through the town of Goliad, home to an 18th-Century San Antonio mission and presidio. This far south, the river is muddy and winding, with a strong current until its confluence with the larger Guadalupe River in Refugio County. All of the trash and other pollution that originates in Bexar County eventually flows through these areas on its way to the Gulf of Mexico.
Why It Matters
Connected Water, Connected Communities
Clean Water
Healthy watersheds help protect the quality of the water that flows through our communities.
Healthy Ecosystems
Healthy waterways provide habitat for plants and wildlife and support thriving natural environments.
Healthy Communities
Our waterways connect neighborhoods, parks, businesses, and people throughout the region.
What Happens on Land Doesn’t Stay on Land.
Rainwater moves across roads, neighborhoods, businesses, parks, and other surfaces before entering our waterways.
Along the way, it can carry trash, pollutants, sediment, and other materials into our creeks and rivers.
Trash is often what we see—
but it’s only part of the story.
Protecting Our Watershed Starts With Us.
River Aid San Antonio works with volunteers and community members to promote stewardship of the San Antonio River Basin.
Through cleanups, water quality monitoring, conservation, and community engagement, we help people become active stewards of the waterways we all share.
Watershed Clean-up Program
Remove litter and help restore our waterways.
Lorence Creek Preserve
Protect and care for an important natural area.
Water Quality Monitoring
Help us better understand the health of our waterways.
OUR IMPACT
Real Programs. Measurable Results.
The success of our programs is measured in cleaner waterways, healthier habitats, and stronger communities.
Every Action Flows Downstream.
Whether you’re volunteering for a clean-up, protecting a natural area, monitoring water quality, or simply learning more about your watershed, your actions can make a difference.
One City
One River
One People
Help Protect Our River
Our waterways belong to all of us. Join River Aid San Antonio in protecting the San Antonio River Basis for our communities and future generations.