Rivery Park’s wet pond isn’t just for looks
Broad-leafed, yellow-hued water lilies and sprawling, interlaced pondweed float on the surface of the Rivery Park Wet Pond, edged by shallow-water ferns, bulrushes, and horsetails. On a warm afternoon, twelve-spotted skimmer and common whitetail dragonflies hover and dart over the green, cool water. Chirping frogs raise their voices on summer nights, and visitors as diverse as black-tailed jackrabbits and long-tailed weasels find their way to the pond’s banks. Amid this rich diversity of native Texan flora and fauna, however, a casual observer may miss the most vital function of this small, manmade body of water—filtering pollutants from storm water runoff.
“The wet pond at Rivery Park is primarily designed to biologically treat storm water runoff from the Rivery commercial developments,” explains Eric Nuner, Assistant Parks and Recreation Director for the city of Georgetown. “Plants, algae, and bacteria in the pond remove pollutants by capturing, filtering, and removing them. [This] treatment . . . is very important to ensure pollutants do not enter the Edwards aquifer,” on which the 100-plus acres Rivery Park development is located. Nuner adds, “Another benefit is the aesthetic nature of the pond. Watching and listening to the multitude of migratory birds and looking to see what wildflower is currently blooming makes you forget that I-35 is right next door.”
Located near the Middle Fork of the San Gabriel River, the wet pond consists of a forebay, which captures heavier pollutants and requires dredging after a number of years, and the main pool, which helps to dissolve the remaining pollutants through biological activity. Most of the important work is done in the main pool, primarily under the surface of the water, by microscopic bacteria, slimy algae, and fuzzy fungi. Decomposing plant matter, such as rotting leaves, also helps filter harmful pollutants, which may include excessive amounts of nitrates or chemicals in the water.
The model for the Rivery Park wet pond comes from wetland areas that occur naturally and help to support healthy ecosystems and water supplies. “[The wet pond] is designed to reflect a natural wetland or spring,” Eric notes. “This is reflected in the selection of native plant[s] . . . that [are used] in and around the pond. These plants, wildlife, and fish contribute to the appearance of a natural pond that you would typically find in a rural setting. Such an ecologically diverse pond in this urban setting is a real gem.”
Georgetown Parks and Recreation