Thursday, October 16, 2014

Waterblogue A conversation about sustainable water by David Venhuizen

Can Dripping Springs, and developers there, bust out of the 19th century?

Or will they choose to remain stuck there. Because, you know, that is a choice they are free to make.
It’s a simple proposition, really. If your aim is to maximize use of the water resource we mistakenly call “wastewater” to defray demands on the area’s water supplies, then it just makes sense to design the “waste” water system around that principle. It doesn’t make sense to instead use a large majority of the money dedicated to this function to build a large-scale system of pipes and pump stations focused on making what’s misperceived as a nuisance to go “away”, then to spend even more money on another large-scale system of pipes and pumps to run the reclaimed water back to where it came from in the first place!

That’s the standard MO of our mainstream institutions, like the City of Dripping Springs and the engineers who advise it and developers whose projects would feed into the city’s centralized wastewater system. This centralized management concept was a response to the conditions considered paramount in the 19th century. The industrial revolution was in full force, city populations were exploding, the stuff was littering the streets, creating a stench and a serious threat of epidemic disease. The response was to pipe it “away”, to be deposited in the most conveniently available water body. Later, as it was realized those water bodies were being turned into foul open sewers, creating a threat of disease in downstream cities that withdrew their water supplies from them, treatment at the end of the pipe was considered, and eventually adopted as the standard.

The intellectual leadership of the centralized pipe-it-away strategy was centered in well-watered areas like northern Europe and the northeastern and midwestern areas of the US. So the resource value of that “waste” water was never part of the equation. This water, and the nutrients it contains, was viewed solely and exclusively as a nuisance, to be made to go to that magical place we call “away” – the working definition of which is apparently “no longer noticeable by me.” This centralized pipe-it-away strategy became institutionalized as the manner in which cities manage wastewater.
Of course, that strategy flies in the face of the circumstances confronting us here in Central Texas in the 21st century – that water, all water, is a valuable resource which we can no longer afford to so cavalierly waste by addressing it solely and exclusively as if it were just a nuisance, simply because that is what the prevailing mental model dictates. Rather, it’s imperative we practically maximize the resource value of that water, using it to defray demands on the area’s water supplies, which are being stressed by both chronic drought and population growth.

In the Texas Hill Country, we also have an issue with surface discharge of wastewater, even when treated to the highest standards that the Texas Commission on Environmental Quality (TCEQ) has so far formulated. And before proceeding I’d note that this issue would remain even if the whole system were to operate perfectly all the time. But of course, it will not; there will inevitably be “incidents”. Which brings up the issue of the vulnerability created by centralization. I’ve often said, not entirely tongue-in-cheek, that the real point of regionalization – TCEQ-speak for centralizing flow from as far and wide as can be attained – is to gather all this stuff together at one point where it can really do some damage. Indeed, the whole organizational strategy is a “vulnerability magnet”. Large flows being run through one treatment plant or one lift station or one transmission main means that any mishap may create large impacts.

Back to the issue with discharge in the Hill Country, the major problem is those nutrients in the wastewater, in particular nitrogen. A discharge of the magnitude that an expanded Dripping Springs system would create, centralizing wastewater flow from developments for miles around the city in every direction, would make the receiving stream effluent-dominated. This would be partly an artifact of the drawdown of local aquifers drying up springs and thus reducing natural streamflow – again highlighting how critical it is to defray demands on these local water resources – but in larger part due simply to the magnitude of the wastewater flow. Highlighting the problematic nature of “permitted pollution” when the flow has been centralized so that, even with low concentration limits, the mass loadings may still be “large”. The nitrogen would cause chronic algal blooms in the creeks, making them very green most of the time, and then depleting oxygen in the water when the algae die off, degrading the riparian environment.

This is deemed an aesthetic affront by downstream landowners. But even more critical, the stream that would receive Dripping Springs’ discharge is Onion Creek, a major source of recharge to the Edwards Aquifer. That’s a sole source aquifer supplying water to about 60,000 people and is the source of Barton Springs, which is home to endangered species. So there’s great antipathy to any plan by Dripping Springs to discharge.

The “standard” option is to continue to “land apply” the effluent from its wastewater treatment plant – “irrigating” land for the sole purpose of making the water go “away” rather than to enhance the landscape or grow a cash crop – which the city does under its current permit. This practice is more accurately termed “land dumping”, and in this region, in this time, it is an unconscionable waste of this water resource.

At least discharge would have some utility, providing more constant flow in the creek, enhancing the riparian environment, and a more constant recharge of the Edwards Aquifer. That is, it would have utility if the water were to be treated to a standard that would preclude the “insults” noted above.
In regard to nutrients, that is technically possible – albeit unlikely to be required by TCEQ – but it would be quite expensive. Burnet discovered that treating to a higher standard to allow them to discharge into Hamilton Creek, which eventually flows into the Highland Lakes, would add about $10 million to the cost of their treatment plant. But that still won’t attain the high removal rate demanded for discharge into Hill Country creeks that recharge the Edwards Aquifer.
But nutrients aren’t all there is to be concerned about. There are also “contaminants of emerging concern” – pharmaceuticals, in particular endocrine disruptors. What it would cost to make discharge “safe” in this regard is an open question – another subject for another time. Suffice it to note here that TCEQ has no standards addressing these pollutants, thus there is no requirement to even consider what might be “safe”.

The latest word is that the overwhelming dissatisfaction with a discharge scheme has urged Dripping Springs to drop its plans to seek a discharge permit – for the present. It’s unclear if that means it would just expand its “land dumping” system (a rather costly proposition, due to the land requirements, so Dripping Springs might soon decide that’s just too expensive and would request a permit to discharge). Or would the city pursue any and all opportunities to route the treated effluent to beneficial reuse? Likely mainly within the developments generating the flow as few other opportunities have been identified, the 8-acre city park being the only one mentioned in the version of the Preliminary Engineering Planning Report (PERP) the city released last summer.

Which brings us to how the city would create a system plan predicated on beneficial reuse of this water resource to defray demand on other water supplies. The city appears to be leaning toward simply appending onto the already costly 19th century conventional centralized wastewater system another whole set of costly infrastructure to redistribute the water, once treated, back to the development that generated it. Note, however, that as TCEQ presently interprets its rules, the city will still be required to have a full-blown “disposal” system in place regardless of how much of that water they expect to route to beneficial reuse, making that whole concept somewhat problematic if indeed no discharge option would be sought. This focus of TCEQ rules, as currently applied, on “disposal” of a perceived nuisance, to the exclusion of focusing on integrated management of water resources, is an issue for any sort of plan the city may consider, highlighting the need to press TCEQ to reconsider that focus.

Indeed the city’s centralized plan would be costly. Dripping Springs is keeping its present engineering analyses close to the vest, but according to the version of the PERP released last summer, the three interceptor mains in that plan – denoted “east”, “west” and “south” (leaving us to wonder what will be done with development that may occur to the north) – and their associated lift stations would have a total cost of about $17.5 million. These are costs, along with the estimated $8.1 million for treatment plant expansion and an estimated $1 million for permitting, that must be sunk into the system prior to being able to provide service to the first house in the developments this system would cover. Then there is the cost of centralized collection infrastructure within the developments, to get their wastewater to those interceptors, no doubt running into the 10’s of millions at complete buildout.

And for this, all they get is “disposal” of a perceived nuisance!
With, as noted, the issue of how the water would be “disposed of”, if it is not discharged, still to be resolved – and paid for. If it is to be redistributed back to the far flung developments generating the flow, the facilities to do that will add many more millions to the overall cost of the complete system.
Far less costly, in both up-front and long-term costs, would be the creation of a 21st century system that would be designed around reuse, rather than “disposal”, of this water resource right from its point of generation. The city could pursue a decentralized concept strategy, focused on treatment and reuse of this water as close to where it is generated as practical, obviating the high cost of both the conventional centralized collection system and the reclaimed water distribution system.
Entailing a number of small-scale systems designed into rather than appended onto development, it is highly doubtful that the city could unilaterally impose that sort of system. The large developments around Dripping Springs are all planning – indeed they have obtained TCEQ permits for – smaller conventional centralized systems within each of them, featuring “land dumping” as the intended fate of the water. In fact, Dripping Springs has “sponsored” the permit for one of those developments, so is actively promoting this strategy. The development agreement with another large project specifies that the wastewater generated in that development must be run into the city interceptor whenever it is built, despite the development-scale system being in place. So if the city does develop interceptors that would drain wastewater from those developments to an expanded centralized plant, then these development-scale systems would be stranded assets, sunk costs incurred simply to allow development to begin prior to completion of the city interceptor, then to be abandoned, basically wasting the fiscal resources required to install them.

It’s clear then that Dripping Springs could pursue a decentralized concept strategy to expand service capacity to encompass those developments only if each of them were to cooperate in planning, designing, permitting and implementing the decentralized system, instead of those development-scale centralized systems they’re presently planning to build. But of course, unless Dripping Springs presumes a leadership role, the developers have no impetus to consider that. They must presume they’d have to abandon any sort of development-scale system and run their wastewater “away” into the city’s centralized system whenever interceptors were extended to their properties.
To pursue a decentralized concept strategy it must be determined how such a system would be organized and how it could be permitted, given the “disposal”-centric focus of how TCEQ wields its rule system. This is a complex subject that does not well lend itself to this medium. Complicated by the decentralized concept remaining “non-mainstream” despite it having been out there for quite a long time – I defined the decentralized concept in 1986, and it was “ratified” as a fully legitimate strategy in a 1996 report to Congress, among other milestones – so its means and methods remain largely unfamiliar to regulators, engineers and operating authorities. Further, being designed into rather than appended onto development, the details would be sensitive to context; while there are recognized organizing principles, there is no “one size fits all” formula.

For the interested reader, a broad overview is “The Decentralized Concept of Wastewater Management” (in the “Decentralized Concept” menu at, and a basic review of those organizing principles are set forth in this document, reviewing wastewater management options in the nearby community of Wimberley. But a review of exactly how to design a decentralized concept system for any given project in and around Dripping Springs is properly the subject of a PERP for each project, not something that can be credibly described here, absent any context. The means and methods are, however, all well understood technologies that can readily be implemented to cost efficiently maximize reuse of this water resource.

Highlighting that the most salient feature of a decentralized concept strategy in the context of this region is the “short-stopping” of the long water loops characteristic of the conventional centralized strategy, so that reuse of the water resource would be maximized at the least cost. It is this 21st century imperative that should motivate Dripping Springs and the developers working in that area to explore the decentralized concept. A necessary part of that exploration is to press TCEQ to consider how it interprets and applies its present rules, and perhaps to consider the need for “better” rules that recognize our current water realities. None of this can be served up for the city or the developers as a fait accompli in this medium; it is a job they have to undertake. One which we all need them to undertake, for the benefit of this region’s citizens, current and future.
But from all indications to date, it does not appear they will even try – they just can’t seem to expand their mental model of wastewater management to encompass it. The result of which is that most of this wastewater will live down to its name for a long time to come, driving us ever further away from sustainable water. So the question is posed: Can Dripping Springs, and the developers there, bust out of the 19th century – or will they choose to remain stuck there?

No comments:

Post a Comment