The Mexican Buckeye

Last week, as my dog Molly and I walked the San Gabriel River Trail, I spotted one of my favorite trees, the Mexican buckeye (Ungnadia speciosa Endl.), also known as the Texas buckeye and canyon buckeye. Really more of a shrub than a tree, the Mexican buckeye is easily distinguished during much of the year by its reddish brown, three-lobed fruits that hang from the tree and that rattle when shaken. Inside are three large, lustrous black seeds. The Mexican buckeye grows along rocky ravines and bluffs above streams in Texas and New Mexico. The tree Molly and I saw on our walk was actually growing on top of a limestone boulder about 30 feet above the San Gabriel. In the spring, the tree has clusters of small, beautiful pink flowers, which eventually give rise to the fruits and seeds.

The seeds of the Mexican buckeye have been found in large numbers among Native American archeological sites, but experts disagree about whether the seeds were eaten, used as psychotropic substances, or worn as ornaments. The seeds contain compounds that are known to be toxic and there are anecdotal reports of people becoming sick and even dying from eating the seeds. However, several botanists claim to eaten eaten the seeds with no ill effects. Regardless of what the botanists say, I don’t recommend trying them!

Reference: Turner, M. W. 2009. Remarkable Plants of Texas: Uncommon Accounts of Our Common Natives. University of Texas Press, Austin.

Southwestern University Student Projects on the San Gabriel River

Last fall, I taught a First Year Seminar Course at Southwestern entitled A River Runs Through It: The Ecology and History of the San Gabriel River. Students in the course were required to plan and carry out a group research or creative project that focused in some way on the San Gabriel River. Another requirement was that the project include members of the community. Here are brief summaries of the student projects, written by the students.

Memoirs of the San Gabriel River
Bridget Miller, Jessica Perry, Elizabeth Marzec, and Erin Landry

Rivers are an essential part of civilization, both as a cultural hub and a resource. The San Gabriel River and Park is no exception. Despite being an extremely important river in Georgetown and Williamson County, there is very little documented about the river, especially personal tales. We realize that the San Gabriel River is a significant part of the Georgetown community and attempt to convince others of this as well. In efforts to prove the significance of the San Gabriel and collect a lasting oral history of the river, we interviewed residents from all over town, of all ages, to capture feelings and memories involving the city of Georgetown and more specifically the San Gabriel River and San Gabriel Park. We comprised the interviews into a documentary DVD. Through this project we have discovered the positive feelings of fondness that the community has for the beloved San Gabriel River and Park. We hope this film will help teach the residents of Georgetown about the history of the area and for them gain more appreciation for its rich history.

Fossils of the San Gabriel River
Kirby Crone, Kate Castles, Kristen McCollum, Kim Sump

The community as a whole does not know the history of the San Gabriel River and its past, so our group decided to teach them by means of fossils that are found in the region. We hiked along the river and in nearby areas and found nine different kinds of fossils. We classified the fossils and put them into three groups (commonly found, occasionally found, rarely found). We then designed a kiosk to put at the head of the San Gabriel River Trail that has pictures and descriptions of the fossils we found, an illustration of how fossils are formed, and a map that details the geological history of the area. Our project's purpose is to inform and educate the community about Georgetown's past and encourage children to become enthusiastic about science by means of fossils. Fossils commonly found included Turitella, and Texigryphaea. Fossils occasionally found consist of Ostrea, Protocardia, and Pecten. Fossils rarely found are composed of Pholyadomya, Loriola, Tylostoma, and Inoceramus. On one of our many fossil hunts, we went to Lake Georgetown. It was about a twenty minute walk through a forested trail until we got to the waters edge. Right as we were getting there the sun was starting to set, so we had to find fossils quickly. This was not a problem because when we looked down we realized the entire ground was just covered in various types of fossils. By going on each fossil hunt we have been able to see into a world that few have been able to explore. It is truly amazing to see what had been millions of years before our existence and hold that piece of history in your hands.

Analysis of Trash on the San Gabriel River Trail

Kevin Burge, Allard deJong, Alex Essex-Carmona, and Alexander Reinsch

On a hike along the San Gabriel River Trail, these students noticed litter along the trail. They decided to conduct a scientific analysis to better understand where along the trail litter might be a problem and how it might be better managed. An initial hypothesis was that litter was more likely to occur where there were fewer trash cans. The students divided the trail into sections. They collected trash along the trail, recording the number of pieces of trash found in each section and the type of trash collected. They also interviewed trail users to determine their impressions and attitudes about trash along the trail. Results of the study showed that the trail is relatively free of litter and trash. The amount of litter was not related to the presence of trash cans. Instead, areas that contained more litter were located near roads and streets, suggesting that most litter does originate not from trail users, but comes from passing vehicles. Adding additional trash cans is unlikely to decrease the amount of litter that occurs along the trail.

More Dino Tracks on the San Gabriel

Yesterday, Marlene and I celebrated our 28th wedding anniversary by looking for dinosaur footprints on the South San Gabriel River. The previous weekend, we had located some great dinosaur tracks on the North San Gabriel (see Wading the San Gabriel post). This weekend, we headed to the South San Gabriel near Leander, where a well-known trackway exists.


We made our way down to the river, emerging upon a smooth bed of limestone that formed the river bottom. The river was down to just a trickle, but was clean and clear. Several other people were already there, also looking at the dinosaur tracks. A small boy threw rocks for our dog Molly into the river, which Molly promptly retrieved, much to the delight of both.

The trackway of dinosaur prints is pretty spectacular. Each print is about 10 inches long and separated from the next print by 3 to 4 feet. We counted 11 prints in all.

After examining the tracks, we hiked up the river a short ways, while Molly splashed around chasing small fish and swimming in the deeper pools. We topped off the day with a four-star dinner at Cafe Josie in Austin and then headed to Zilker Park to watch the outdoors performance of Beauty and the Beast.

Wading the North San Gabriel

Last weekend, my wife Marlene and I waded the North San Gabriel River with our dog Molly. It was a clear hot day, perfect for wading. We were in search of dinosaur footprints, which I had been told could be found on this stretch of the San Gabriel.

The river was beautiful--crystal clear water flowing gently over solid rock bottoms. As we made our way upstream, a heron flew overhead and cricket frogs called from the banks. Because of the sparse rainfall this spring and summer, the river was low, less than a foot in most places, which made wading easy. Molly had a great time splashing around, chasing minnows and small bass.

We walked for a mile and half and didn't see another person. Half a mile upstream we passed 40-foot cliffs. Great chunks of limestone, almost perfectly rectangular and looking like they were cut from a quarry, lay in the river bed. Further on we passed several deeper pools, where Molly was able to swim around without touching bottom. At one point, underground springs fed cool water into the river and the water temperature dropped dramatically. Vines hung overhead, providing natural swings over the water. As we walked upstream, we searched diligently for the dinosaur footprints, but without success.

After about an hour of walking, we turned around and headed back, convinced that the dinosaur tracks were either covered in mud, or worn away, or maybe never existed. I happened to look down, and there next to the river was a foot-long dinosaur print, perfectly preserved in the hard limestone. Several additional tracks, more weathered and less obvious, extended back in a clear trackway. Alone on the river, it was easy to imagine a dinosaur slowly lumbering across the muddy river bottom 100 million years ago, leaving the beautiful tracks that, against all odds, have survived to this day.

Trails on the San Gabriel River

An excellent system of hike and bike trails allow year-round access to portions of the San Gabriel River and Lake Georgetown. The San Gabriel River Trail consists of over 30 miles of hike and bike trails along the San Gabriel River and Lake Georgetown. The trail begins in San Gabriel Park in Georgetown and runs along the North San Gabriel River about 6 miles to Lake Georgetown. Another 1-mile section of the trail loops over to Blue Hole, a beautiful and popular swimming spot on the South San Gabriel. Hiking or biking along the trail, one crosses the North San Gabriel several times and passes a wetland pond (at Rivery Park), the remains of the Shell family house (where the Shell family lived in the early 20th century), and a large spring. Wildlife is abundant along the trail: one often encounters deer, bats, beaver, buzzards, frogs, herons, and kingfishers. Wildflowers grow abundantly along the trail (see Phyllis Dolich’s blog on Wildflowers of the San Gabriel River Trail). Access to the trail is available at several spots within the city of Georgetown, including San Gabriel Park, Rivery Park, Bootys Crossing Road, Chandler Park at Spring Valley Road, and North Cross Road. Most of the trail from San Gabriel Park to Lake Georgetown has an all-weather surface that is wheel-chair accessible

At Lake Georgetown, the Good Water Loop of the San Gabriel River Trail begins. This 26-mile rugged loop completely encircles the lake. Here the trail passes through oak and juniper forests, river bottom hardwoods, and prairie grasslands. On the north side of the lake, west of Russell Park, the trail traverses bluffs high above the lake, affording some spectacular views, and passes several small caves, before descending to the lake. It then follows the path of the old river road that traveled up the North San Gabriel River before Lake Georgetown was built (see earlier posting on San Gabriel River Crossings). The trail crosses over to the south side of the lake at historic Hunt Crossing (a popular fishing spot) and then passes through Tejas camp and runs along the south side of the lake. A spectacular stop in this stretch is Crocket Gardens, a lush oasis where a natural spring cascades over a 30 foot cliff into the waters of Lake Georgetown lake.
Supported by funding from the 3M Foundation, a partnership between Southwestern University, the City of Georgetown, and the Corps of Engineers sponsors research and educational projects that benefit the San Gabriel River Trail. More about this project can be found at: www.southwestern.edu/sgrtp/

Wildflowers on the San Gabriel River Trail, Is Global Warming Causing Them to Bloom Earlier?

by Phyllis Dolich

Phyllis Dolich has been a resident of Sun City Texas in Georgetown for eight years. She served as president of the Sun City Texas Nature Club and president of the Williamson County chapter of the Native Plant Society of Texas. She is a member of the Lady Bird Johnson Wildflower Center and the Butterfly Forum of Austin. Her garden was featured in the Wildflower Center’s Native Plants magazine and on PBS’ Central Texas Gardening.

In 1852 and 1853, Eliza Griffin Johnston, who was living in Austin, Texas created 100 watercolor paintings of the wildflowers which surrounded her home. Each was accompanied by a hand-written observation which included the bloom time. Many of the wildflowers I have observed on the North San Gabriel River Trail are included in Mrs. Johnston’s collection which was donated to, and later allowed to be published by, the Daughters of the Republic of Texas. The book, Texas Wildflowers, was published by Shoal Creek Publishers in Austin in 1972.

Although I have observed and recorded 123 wildflower species on the trail between 2001 and 2007, I will limit the following analysis to just those found in Eliza’s collection. The following table lists the plants by family and compares Eliza’s bloom times with the bloom times reported by Marshall Enquist in Wildflowers of the Texas Hill Country (Lone Star Botanical, Austin, Texas 1985). His observations correspond with my own (in some cases, mine are even earlier).

Conservation biologist, Richard Primack, of Boston University is conducting a similar analysis at Walden Pond where Henry David Thoreau made observations of flowering plants and their bloom times 155 years ago. (See The Science Journal in the Wall Street Journal, Friday, June 13, 2008, page A10) Species

Blooming Earlier

Ruellia nudiflora (Engelm. & Gray) Urban, wild petunia
Bloom Time 1852: May throughout summer
Bloom Time Now: April-Nov

Yucca rupicola, twist-leaf yucca
Bloom Time 1852: May
Bloom Time Now: April-June

Engelmannia pinnatifida, Engelmann's daisy
Bloom Time 1852: from May until the end of summer
Bloom Time Now: Feb/March-July

Symphyotrichum drummondii, Texas aster
Bloom Time 1852: November
Bloom Now: Sept-Oct/Nov

Opuntia macrorhiza Engelm, Prickly Pear, Grassland
Bloom Time 1852 (O. engelmannii var. lindheimeri): May
Bloom Time Now: April-May

Viburnum rufidulum Raf. , rusty blackhaw viburnum
Bloom Time 1852: Mar 21
Bloom Time Now: Feb/March-May

Ibervillea lindheimeri (Gray) Greene, balsamgourd
Bloom Time 1852: middle of June
Bloom Time Now: April-Sept

Lupinus texensis Hook, Texas bluebonnet
Bloom Time 1852: end of March
Bloom Time Now: Feb/March-May

Phacelia congesta, blue-curls
Bloom Time 1852: during May and June
Bloom Time Now: Feb-May

Calylophus berlandieri Spach, Berlandier's sundrops, Square-bud primrose
Bloom Time 1852: 6 or 8 weeks fr beg of April
Bloom Time Now: Feb/March-Aug

Gaura lindheimeri, White Guara,
Bloom Time 1852: March 25
Bloom Time Now: Feb/March-June

Oenothera jamesii Torr. & Gray, james evening or river primrose
Bloom Time 1852: August and September
Bloom Time Now: July-Oct/Nov

Oenothera speciosa Nutt. pink or showy evening primrose
Bloom Time 1852: early April
Bloom Time Now: Feb/March-July

Argemone albiflora Hornem. ssp. texana G.B. Ownbey white pricklypoppy
Bloom Time 1852: April
Bloom Time Noww: Feb/March-May

Clematis pitcheri Torr. & Gray, pitcher clematis, purple leatherflower
Bloom Time 1852: August
Bloom Time Now: May-July

Agalinis heterophylla (Nutt.) Small ex Britt., prairie agalinis, false-foxglove
Bloom Time1852: 2 or 3 weeks in October
Bloom Time Now: Sept-Oct/Nov

Castilleja indivisa Engelm. Texas paintbrush
Bloom Time 1852: April
Bloom Time Now: Feb/March-May

Solanum elaeagnifolium Cav. silverleaf nightshade.
Bloom Time 1852: June and July
Bloom Time Now: April-Sept

Solanum rostratum Dunal, buffalobur
Bloom Time 1852: June and July
Bloom Time Now: May-Oct/Nov

Glandularia bipinnatifida (Nutt.) Nutt. var. bipin , Dakota verbena Bloom Time 1852: from April to December
Bloom Time Now: Feb/March-Oct/Nov

Lantana horrida, Texas lantana, calico bush
Bloom Time 1852: April and May
Bloom Time Nov: Feb/March-Oct/Nov

Species Not Blooming Earlier

Ilex decidua, Possumhaw, Deciduous Holly
Bloom Time 1852: end of March
Bloom Time Now: May-July

Gaillardia pulchella Foug., rosering gaillardia, indian blanket, blanketflower
Bloom Time 1852: April and May
Bloom Time Now: April-June

Berberis trifoliolata, Agarita
Bloom Time 1852: Feb 20 - Mar 15
Bloom Time Now: Feb/March-April

Lesquerella gracilis, Bladder-pod or Cloth-of-Gold
Bloom Time 1852: March 21
Bloom Time Now: Feb/March-May

Tradescantia occidentalis (Britt.) Smyth (T.humilis), spiderwort, western spiderwort
Bloom Time 1852: April and May
Bloom Time Now: April-June

Cnidoscolus texanus (Muell.- Arg.) Small, bullnettle
Bloom Time 1852: April - November
Bloom Time Now: April-Sept

Chamaecrista fasciculata (Michx.) Greene, partridge pea
Bloom Time 1852: April (earlier than now?)
Bloom Time Now: May-Oct/Nov

Indigofera miniata Ortega, western indigo, scarlet pea
Bloom Time Now: April-Oct/Nov

Nemophila phaceloides, baby blue-eyes
Bloom Time 1852: mid-March
Bloom Time Now: Feb/March-May

Callirhoe involucrata (Torr. & Gray) Gray, winecup
Bloom Time 1852: last of March
Bloom Time Now: Feb/March-May

Malvaviscus arboreus var. Drummondii, Turk's Cap
Bloom Time 1852: May to November (earlier)
Bloom Time Now: June-Oct/Nov

Ipomopsis rubra (L.) Wherry, Texas plume, standing cypress
Bloom Time 1852: from early May till October
Bloom Time Now: May-June

Clematis texensis Buckl., Texas clematis, scarlet leatherflower
Bloom Time 1852: late April
Bloom Time Now: April-June

Ungnadia speciosa Endl., Mexican buckeye
Bloom Time 1852: Mar 15
Bloom Time Now: Feb/March-May

Vitis mustangensis, Mustang Grape
no bloom info

San Gabriel River Crossings

Before the development of modern transportation, rivers such as the San Gabriel served as major barriers to travel in Texas: high cliff banks, deep water, and muddy bottoms made crossing with wagons and cattle difficult and sometimes hazardous. Early settlers and later cattlemen quickly discovered sites along San Gabriel where crossing the river was facilitated by shallow water, low banks, and hard bottoms. These “crossings” became widely known and used; frequently mills, stores, and settlements sprung up nearby to take advantage of the traffic. A number of river crossings existed on the San Gabriel and some of these are still used today for low-water bridges.

One of the most important of the San Gabriel crossings was Mankins Crossing, located about 5 miles east of Georgetown, near where highway 29 today crosses the San Gabriel River (turn off highway 29 onto CR 100 and follow it down to the river). The shallow water and solid limestone bottom made fording the river with wagons possible at this site. The site is named for Samuel Mankins, who bought land along the river at this site in 1849 (state historical marker at site). Harvey Stearns build a cotton gin on the west bank of the river at this site in 1892 (Scarbrough, 1973). A concrete low-water bridge that was built in 1931 is still in use today.

Several crossings existed on the North San Gabriel west of Georgetown. The first of these was Booty’s Crossing, which was located about 4 miles west of Georgetown just above the present-day Lake Georgetown dam. This spot was a popular place for swimming, picnics, and fishing (Scarbrough, 1973). Today, Booty’s Crossing Road goes from Williams Drive (FM 223) down to the base of the dam; before the lake was constructed, this road followed the north bank of the river, crossing to the south side at Booty’s Crossing.

The next crossing above Booty’s was Russell Crossing, later called Jenkins Crossing. Frank Russell built a rock house near the crossing in 1868 and later Richard Jenkins settled there. The old rock house remained until 1973, when it was removed for the construction of Lake Georgetown (Scarbrough, 1973). This crossing is now under the waters of Lake Georgetown and sits right off the beach at Russell Park (Carey Weber, personal communication). Jenkins Crossing was sometimes called “Second Booty’s.”

The third major crossing on the North San Gabriel was Box Crossing, which was named for the Box family who settled the area. This crossing is marked on some maps as Hunt Crossing. It now occurs at the upper end of Lake Georgetown, marked by an old low water bridge that spans the river channel.

The fourth crossing, usually called Hunt Crossing, was named for Hayden Hunt who, along with his brothers, built a log cabin near the crossing in the 1850s. Mart Hunts later ran a cotton gin and corn mill on the north side of the river at this site (Scarbrough, 1973). The Hunt family cemetery still exists on the south bank of the river near the crossing.

A fifth crossing occurred further upstream at the Rock House Community (Carey Weber, personal communication). A great short documentary film called San Gabriel River Crossings, made by Diane Koenig in 1974-75, provides a rare glimpse of the North San Gabriel River canyon before it was filled by Lake Georgetown. A copy of the film is in the library of Southwestern University.

Sources

Koenig, Diane. circa 1974-75. San Gabriel River Crossings.
Scarbrough, Clara Stearns. 1973. Land of Good Water (Takachue Pouetsu) : a Williamson County, Texas, History. Georgetown, TX, Williamson County Sun Publishers.

Weber, Carey. Park Manager, Lake Georgetown, US Army Corps of Engineers. Personal communication 17June2008.

Amphibians of the San Gabriel River

Amphibians (frogs, toads, and salamanders) are just one group of animals found along the San Gabriel River. These fascinating creatures typically spend part of their life in the water and part on land although, as we will see, there are exceptions to this biphasic life style. Male frogs call during the breeding season to attract females and each species has a unique call. Summer nights along the river are often filled with the melodious calls of frogs and toads. Listed below are a few of the amphibians that can be found along the San Gabriel River.

Georgetown Salamander
The Georgetown salamander (Eurycea naufragia) is a spring- and cave-dwelling salamander that occurs only in the San Gabriel River basin in Williamson County—it is found no where else in world. Brownish in color, the salamanders are shy, usually hiding under rocks or leaves. Adults are only about 2-3 inches long. Unlike most amphibians, the Georgetown salamander is unable to live out of water and is entirely aquatic throughout its life. We know of its presence at only about a dozen sites along the San Gabriel. The Georgetown salamander is currently a candidate for listing as an endangered species, which means that some people have proposed that it be added to the endangered species list, but it has not yet been listed as endangered by the US Fish and Wildlife Service.

Northern Cricket Frog
The northern cricket frog (Acris crepitans) is the most common amphibian found along the San Gabriel River. Its call, which sounds similar to knocking two stones together, can be heard at all times of day and night in many places on the river. Adult cricket frogs are very small—only about an inch long in body length—and vary in color and pattern; many are gray or brown with greenish spots. The frogs frequent rocky shores and vegetation along the shores of the San Gabriel.

Green Tree Frog
Green tree frogs (Hyla cinerea) are one of the most beautiful amphibians on the San Gabriel River. Adults are usually about 1 to 2 inches in body length and bright green, with a white strip running down each side. Their toes have small suction cups that allow green tree frogs to climb reeds, bushes, and small trees near the water’s edge. Green tree frogs have a distinctive call that sounds somewhat like a goose honking. They often call in large choruses among reeds in shallow water, their calls filling the night air and traveling long distances.

Rio Grande Leopard Frogs
Rio Grande leopard (Rana berlandieri) frogs are found on western portion of the San Gabriel. Adults are green or brown with large spots, giving rise to the name leopard frog. The call of the Rio Grande leopard frog sounds like a snore, often punctuated with one or more squeaky grunts. These frogs breed over an extended period, in spring, summer, or fall following warm rain.

Southern Leopard Frogs
Southern leopard frogs (Rana sphenocephala) are cousins to the Rio Grande leopard frogs; the two species are very similar in appearance, but their calls are easy to differentiate. While the Rio Grande leopard frog’s call is a snore, the southern leopard frog sounds more like a laugh. Both species often add a squeaky grunt to the end of their call. The southern leopard frog is a more easterly species and it is most often found east of Georgetown on the part of the river that passes through the Blackland prairie. The southern leopard frog breeds in late winter and spring, although it can sometimes be heard well into the summer months.

Gulf Coast Toad
The most common toad of central Texas, the Gulf Coast toad (Bufo nebulifer) is found in a variety of habitats, including rivers, ponds, roadside ditches, and urban neighborhoods. These toads are usually 2 to 4 inches in body length and brown or gray, with dark strips running along each side. Its call is a long trill, lasting 2-6 seconds. It can often be heard along the San Gabriel after late spring and summer rainfall.

Cliff Chirping Frog
The cliff chirping frog (Syrrhophus marmockii) is unusual in that it lays its eggs on land. The tadpoles complete development within the egg and little miniature frogs hatch from the eggs. The cliff chirping frog is confined to the Edwards Plateau of Texas. Adults are usually ¾ to 1 ½ inch in body length and greenish, mottled with brown. The frogs inhabit cliffs and rock crevices along the river. They are especially common below the dam at Lake Georgetown, living in and among the large rocks used to construct the dam. The call is a bird-like chirp that sometimes becomes a short trill.

Bull Frog
The largest frog of central Texas, the bull frog (Rana catesbeiana) prefers slow and deeper water. It can be found along the San Gabriel where the water has been deepened by low-water dams. Usually light or dark green, this species is easily recognized by its large external ear drum. Its call is a series of slow, deep, vibrant notes that sound like “jug-o’-rum”.

My students at Southwestern University and I are currently conducting surveys of frogs along the north San Gabriel River between San Gabriel Park and Lake Georgetown. Our goal is to better understand how increasing urbanization of the river corridor affects the frogs and toads found there.

Introduction to the San Gabriel River

The San Gabriel River of Texas is actually two distinct streams. West of Georgetown, it runs clear, clean, and shallow over limestone cobble and bedrock of the Edwards Plateau—a classic spring-fed Hill Country stream. Flowing through canyons and hills and often flanked by dramatic cliffs, the river drops 750 feet in elevation over a short 50 miles from its origin in eastern Burnet County to Georgetown. But east of Georgetown the San Gabriel’s personality shifts dramatically. Here, as the river cuts through the deep, waxy soils of the Blackland Prairie, the San Gabriel slows and meanders for 65 miles, forming deep green pools that alternate with shallow riffles.

Arising from springs to the east and north of Burnet, the San Gabriel River flows eastward across Burnet, Williamson, and Milam counties for 120 miles before merging with the Little River, which empties into the Brazos River.

The San Gabriel includes three major branches, the North, South, and Middle forks, and two large tributaries, Berry Creek to the north and Brushy Creek to the south. The largest and longest fork, the North San Gabriel begins 12 miles north of the town Burnet; the South San Gabriel arises five miles east of Burnet and flows east to join the North branch in San Gabriel Park of Georgetown. The shorter Middle San Gabriel arises five miles east of Liberty Hill in Williamson County, joining the North San Gabriel one mile east of I35. Two major dams block the waters of the San Gabriel and form large reservoirs: Lake Georgetown on the North fork and Lake Granger further east.

Sources: Handbook of Texas Online; Scarbrough, Linda. 2005. Road, River, and Ol’ Boy Politics: A Texas County’s Path from Farm to Supersuburb. Texas State Historical Society, Austin, Texas.