May 14, 2004
Walking upstream from Barton Springs along the bank of Barton Creek in the Greenbelt just upstream of Upper Barton Springs we see this as Barton Creek. The bloom in the water is cladophora algae. This part of Barton Creek is demonstrating advanced eutrophication due to excessive nitrogen in the water. This is how receiving waters often look below the discharge from a poorly maintained sewage treatment plant or an overly fertilized golf course – neither of which is the case here.
This photo depicts a section of Lower Barton Creek between Barton Springs and “waste water draw.”We call the ravine this because of the history of leaky sewer line connections in the bed of the ravine – a major drainage for Barton Hills a quarter mile upstream of Barton Springs.
This spring flow section of Barton Creek was filled with one of the largest algae blooms I’ve seen in years. When Matt Lechner and I visited Upper Barton Spring on April 15th, the creek was virtually devoid of this bloom. I believe David Johns believes this bloom is derived from aquifer water. I think it comes from a leaky sewer line buried in the bed of the draw where water moving along it toward Barton Creek co-mingles with aquifer water arising a few hundred feet downstream of the confluence. I’ve considered that this subterranean water flowing under the bed of the ravine may contain quantities of dissolved fertilizer. The Environmental Board is still awaiting a rigorous assessment of exactly what is causing this nuisance bloom.
A very real problem this algae bloom precipitates occurs during flooding events. The tough strands of cladophora algae, “water wool” tend to get tangled up in the bypass grate at Barton Pool. Very quickly the grate is clogged up with detritus bound up in strands of algae which is difficult to dislodge. The result is that high water in the creek goes over the top of the upper dam because the grate is clogged. This causes more sediment than necessary to enter the pool. This then causes a higher level of maintenance to be required to clean out the pool. Excessive roadway derived sediment in Barton Springs pool has a deleterious effect on the Barton Springs Salamander habitat from time to time. In my opinion this perennial algae bloom should be of concern to the folks maintaining the HCP for the Barton Springs Salamander.
The lower photo is of Barton Creek perhaps a hundred yards or so upstream of the above photo. It depicts an area just above a heavily vegetated gravel bar across Barton Creek, colloquially known as Randy Goss Blvd., where maybe 1 or 2 cfs of water is passing through an anastomosed drainage filled with water willow. Here the creek has been subjected to drainage from MoPac in the vicinity of Spyglass Trail where the primary drainage into the creek from the west is called Grotto Draw. This draw also drains the Temple Inland property, Spyglass Trail Office Park and the hotel at the corner of Barton Skyway and MoPac frontage road. The primary drainage into the creek from the east in this vicinity is wastewater draw. This photo depicts Barton Creek at the confluence of this draw and Barton Creek.
The hydrology here is more complex than you might suspect because some of the water you see below and most of the water you see in the photo above comes from discharge in small springs from the Barton Springs Edwards Aquifer above Barton Springs.
Wastewater draw is an intermittent stream behind and to the left of what is seen in this photo. Grotto Draw is about two hundred feet upstream on the far side of the creek.
Black road sediment in stormwater runoff from MoPac Freeway, Spyglass Trail and the Barton Hills subdivision gives this spring-pool in Barton Creek its dark appearance. The area is virtually built out at this time – although Temple Inland on the other side of the creek does want to expand its impervious cover.
Yesterday I went down to Barton Springs for a look after the recent storms. The Barton Springs south-side parking lot hadn’t contributed to clouding up the pool with road base sediment because we altered the drainage away from Barton Springs. The pool was slightly murky from spring discharge do to recharge upstream – probably recharge points upstream of the area depicted above.
But I was disappointed to see Barton Creek looking like this, again. Barton Creek is dramatically demonstrating the effects of urbanization and associated stormwater pollution impacts.
If mitigation is not put in place up front this is what you get. Structural controls are often inadequate. But without a well maintained system coupled with impervious cover limits our creeks – our recreational waterways – are rendered into little more than drainage ditches accommodating stormwater runoff from excessive development.
The COA WPD staff and W/WW Dept, the TCEQ Edwards Aquifer folks, TxDOT, USGS, USFWS, SOS, SBCA, BSEACD and other organizations as well as the County Health Dept, and the Environmental Board were made aware of these particular recreational waters in the Barton Creek Greenbelt for more than a decade. The photos above are poignant illustrations of how difficult it is to maintain and retrofit for water quality in the face of aggressive urbanization.
Have we given up on the effort?
The City Council should think twice before it revises the SOS ordinance to accommodate higher levels of development intensity.
Increases in impervious cover are inevitably deleterious to water quality. To allow more impervious cover without insuring compensatory mitigation directed towards improving water quality and riparian regimes in streams in the watershed involved dooms these streams to even more urban pollution.
I am concerned about further sacrificing Lower Barton Creek to development interests in order to obtain funds for land in other watersheds to protect the aquifer. It is desirable and laudable to set aside land to protect Barton Springs. But there has to be a way to buy land without further jeopardizing water quality in Barton Creek.