Cabomba!

September 29, 2014  | By Shoal Creek Conservancy

This blog post was written by Ted Lee Eubanks. To learn more about the author, please visit this site.

Mouth of Shoal Creek by Ted Lee Eubanks
Mouth of Shoal Creek by Ted Lee Eubanks

 

The city traps trash at the mouth of Shoal Creek. The garbage is most noticeable after a heavy rain, when tons of waste are swept down the creek to Lady Bird Lake. The trap at the mouth of Shoal Creek, at least in theory, keeps trash out of Lady Bird Lake and in a spot where it is easier to collect.

The city recently spent millions revamping the peninsula at the mouth of our creek, and, again in theory, this stretch of the Butler trail could be one of the most pleasant on Lady Bird Lake. Yet, as long as the mouth of Shoal Creek is used as a trash receptacle, a model of visual pollution, this stretch of the trail will be one to pass quickly or to  bypass altogether.

Plastic bags have diminished since being banned in the city. Styrofoam cups and food containers, however, still litter the surface of the lake. The lake, after a rain, looks like it has been sprinkled with enormous snowflakes.

 

Fanwort (Cabomba), Lady Bird Lake, Austin, Texas, by Ted Lee Eubanks
Fanwort (Cabomba), Lady Bird Lake, Austin, Texas, by Ted Lee Eubanks

 

The profusion of trash in Lady Bird Lake has been particularly apparent this summer. Fanwort (Cabomba), a native aquatic plant, has spread to cover most of the lake this year. Fanwort roots in the sediments of slow-flowing streams and lake, and the stems reach upward to the surface of the water. Fanwort can become established in water as deep as 10 feet. Fanwort has only recently become well established in Lady Bird Lake, perhaps the result of the recent drought.

There are now extensive rafts of fanwort that can support the trash at the surface of the water. Cups and containers that once sank are now floating for everyone to see. Shoal Creek, behind the boom that forms the trap at its mouth, is now a shore-to-shore fanwort mat. The trash that flows down Shoal Creek after a rain now becomes enmeshed in a fanwort seine.

 

Fanwort (Cabomba), Lady Bird Lake, Austin, Texas, by Ted Lee Eubanks
Fanwort (Cabomba), Lady Bird Lake, Austin, Texas, by Ted Lee Eubanks

 

The fanwort will continue to proliferate until heavy rains scour the lake bottom and wash the plant downriver. At least, that’s the theory. For the time being, the city will need to ratchet up its cleanup program. A good place to start is the mouth of Shoal Creek. Perhaps the city should consider doing away with its boom there (I cannot imagine what it accomplishes), and allow the trash to flow downriver. The alternative (and better for relations with our friends downstream) is to clean this stretch of Shoal Creek of the trash and the fanwort on a more frequent basis.

City staff has lauded fanwort for its contributions to the ecological health of the lake. I can certainly see how many invertebrates and their predators (such as the alligator gar) have benefited from these dense fanwort mats. Boaters on the lake are no fans of the wort, however, and in stretches between Lamar and MoPac they have cleared lanes (intentionally or not) where they can pass unobstructed. The least we can do, then, is to rid these rafts of their trash topping. The intricate plant itself is beautiful, but not when festooned with styrofoam cups and containers.

 

Fanwort flower, Lady Bird Lake, Austin, Texas, by Ted Lee Eubanks
Fanwort flower, Lady Bird Lake, Austin, Texas, by Ted Lee Eubanks