waterblogue

Awhile back there was a “Daytripper” column in the Austin Chronicle about Jacob’s Well in Wimberley, Texas, which began with this:

“Jacob’s Well is dead. We are possibly the last generation to enjoy the cold water on a hot summer day of the iconic swimming hole outside of Wimberley.”

While I had been aware that Jacob’s Well has had low to no flow in the past few years, it was jarring to read it is dead! So I immediately wondered, what can be done to resuscitate it, to restore routine flow out of Jacob’s Well?

The fundamental fact of that whole region, which draws the vast majority of its water supply from the Trinity Aquifer – from which Jacob’s Well and other springs in the area derive – is that it’s “over” pumping from the aquifer that has lowered water levels and led to the dying of the springs. This impact has been exacerbated in the last few years by the enduring drought in this region; the average annual rainfalls have ranged several inches below the long-term average since the last “wet” year, in 2021.

But assuming for the moment pumping could be “adequately controlled”, it is quite possible to enhance recharge, and so better feed the springs, by how the land in the springshed is managed. I’ve long been aware of such practices from my permaculture training, and my awareness has been piqued recently by viewing the work of Symbiosis, LLC – a company that has been doing just that, seeking to cause more rainfall to insoak, and less to run off, to enhance productivity of the land – and by researching beaver mimicry (installing beaver dam analogs, or BDAs, in waterways) as measures to restore the hydrologic function of watersheds, enhancing recharge and stream baseflow.

So I reached out to the Watershed Association, the major NGO in the Wimberley Valley that deals with such environmental matters, and to The Meadows Center at Texas State University, a major center of thinking on all things sustainable water in this region, suggesting a program be created to “treat” land in the Jacob’s Well springshed. Highlighting the work of Symbiosis and examples of beaver mimicry, it was suggested that by applying such works at scale over the watershed, the level of recharge, and of stream baseflow, might indeed be enhanced over this area, better capturing and infiltrating whatever level of rainfall is received. So essentially “rehydrating” and “drought-proofing” the watershed.

We could perhaps start that process with a demonstration project on a portion of the watershed to show the efficacy of such a program, and then seek means of proliferating these measures. Perhaps by tapping into enlightened self-interest of landholders, noting that Symbiosis has shown that is already a market. Or by a program of land “preservation” through outright purchases and conservation easements – which is already being pursued, has been for some time, by the Watershed Association – and doing restoration works on those lands.

To “test” this idea, I ran the question by a couple AI chatbots of whether “treating” the watershed in such manners could indeed increase recharge, and so increase/enhance Jabob’s Well flow. Again, subject to also “properly controlling” pumping out of the aquifer, the ‘bots asserted that if applied at scale over the watershed, these could indeed be effective strategies. For example, one of them asserted, “Scientific models from the Hays-Trinity Groundwater Conservation District suggest that the springshed boundaries closely follow the Cypress Creek watershed. This means that land-based restoration specifically in this watershed has a direct, mechanical link to the flow at the Well.” And so, “Applying ‘permaculture-style’ treatments and Beaver Dam Analogs (BDAs) to the Cypress Creek watershed offers a high-prospect, though geologically complex, path to restoring Jacob’s Well.” I’ll leave further review of all that to other venues, because …

To pursue these strategies will require planning and marshaling public or institutional funding and the participation of a number of landowners. While we await any action toward such a program, I kept coming back to the need to “control” pumping out of the Trinity Aquifer. In particular over the Jacob’s Well springshed, which has been covered by the Jacob’s Well Groundwater Management Zone (JWGMZ), over which minimizing use of groundwater is a priority. Of course, pumping could be stemmed, at least blunting further increases, by simply not further developing in this area. But that runs headlong into the abiding issue that confronts the entire Texas Hill Country, the Wimberley Valley in particular, the tension between the state of water resources there and a landscape into which people are continuing to move.

This is well illustrated in a Wimberley Comprehensive Planning Process report in which it’s touted that “land conservation is water supply strategy”, urging land “preservation” – withholding it from development – on the principle that development would typically degrade the ability of the land to “absorb” water and so feed the aquifer. Cited as an example was the recent dedication of the Karst Canyon Preserve, relating that it is “176 acres adjacent to Jacob’s Well Natural Area, preserved through a decade of grassroots effort when it was slated for 1,600 homes”. The unasked, thus unanswered, question here is where would those 1,600 homes be built instead?

This is relevant because, besides being expensive to continue to “lock up” more land from development, consider that the basic purpose of that whole planning process is to be able to accommodate continued growth in the Wimberley Valley and environs. So if one displaces growth from one area, it must be accommodated somewhere else, if indeed growth is not to just stop altogether. Raising the basic question, can we essentially “preserve” the land, at least in terms of water yield management, as we develop to accommodate that growth? And if so, how?

So suggesting the proposition, if we follow the “right” practices, could we in essence develop our way to sustainable water, at least over an area like the JWGMZ?

As readers of the Waterblogue know, a suite of sustainable water development practices that could well deliver that outcome has been suggested – for example in “The Zero Net Water Concept”. It is argued that those practices would best protect water quality and other environmental values, including enhancing water yield out of a watershed, as the land is developed. This would be done by reducing supply drawn from aquifers and by holding more water on the land, to move through the hydrologic cycle as recharge or baseflow rather than as quickflow runoff. It is also suggested all that could be done while saving money for the developer.

An overview of how those practices might be applied to development in hinterlands like the JWGMZ, to create development that would be a “shining example” of enlightened water management while also reducing fiscal risk and just flat saving money, is as follows:

• Divide the land into lots upon which houses and/or commercial buildings would be owned under a condominium regime, with “airspace” ownership of the buildings and all the land owned in common by the condominium association. This would be done because …
• Each lot would have the amount of development built upon it that would require a wastewater system with a design flow rate at or below 5,000 gallons/day. The condo arrangement could allow higher density than can typically be attained with individual on-site systems on separate lots, and would allow the buildings and pavement to be “clustered”, leaving more of the site undisturbed, so reducing land fragmentation. But most notably it would allow the wastewater systems to be permitted as OSSFs (On-Site Sewage Facilities, regulatory-speak for what are commonly called “septic systems”) by the local regulatory agent (county or river authority) instead of through the Texas Commission on Environmental Quality (TCEQ) “municipal system” permitting process.
  • This would shorten the timeline for approval of the wastewater system permit, typically to a couple months, as opposed to a year or more for the TCEQ process. The costs of permitting would be considerably reduced, and the OSSF permits would not be subject to formal protests and consequent public hearings, reducing risks of delay. Saving time, saving money.
  • Under this distributed management concept, the OSSF on each lot would not have to be planned, designed and built until buildings are to be built on that lot. The approval process for that OSSF could be completed while the buildings are being built, as could the installation, as these “small” systems could be built on a very short timeline. This delivers a “time value of money” by delaying these expenditures until they are actually needed to serve each “cluster” of development. Saving money.
• An immediate question will be if wastewater management with OSSFs would provide the high level of environmental protection desired and expected in the JWGMZ watershed. Indeed, as envisioned here, they would provide a superior level of protection of water quality and other environmental values, because …
  • The wastewater systems would employ the highly robust, inherently stable and reliable High Performance Biofiltration Concept (recirculating packed-bed filter) treatment unit, producing a high quality effluent, including removing a majority of the nitrogen, a major pollutant of concern in groundwater recharge. The effluent would be dispersed in subsurface drip irrigation fields, where further nitrogen assimilation would occur via plant uptake and in-soil denitrification, and phosphorus would be completely assimilated. All done in a manner similar to what is illustrated in “This is how we do it”. These technologies are widely known and understood in this field, and have been permitted many times in many Texas jurisdictions, so entail negligible regulatory risk.
• • Ideally the dispersal fields would be arrayed to irrigate the highest value landscaping on the lot, which would typically be grounds beautification around the buildings, so beneficially reusing this water resource to largely take irrigation off the potable water supply system, so saving that amount of water – pumpage out of the aquifer – day by day, year by year. Saving water, saving money.
  • With the reclaimed water flowing to the field every day without regard to the weather, clearly the drip irrigation field would have to act as a “drainfield” at times, like during rainy periods. That just means some of the water will exit the root zone by deep percolation rather than by evapotranspiration. Between the high quality pretreatment and passage through the soil, the minor fraction of annual flow that does percolate would be highly renovated before joining environmental waters.
• If condominium ownership is deemed not suited to the target market, a conventionally lotted-out development could still be served by the same type of wastewater system, again as is illustrated in “This is how we do it”. The timeline and permitting costs would increase, but the same highly environmentally sound outcomes would be attained, as would the cost advantages of the distributed management concept.
• Ideally the lots would be arranged so that each has frontage on/access to a public road, so that roads to the buildings would be private drives within the lots, rather than platted streets.
  • While these drives would still have to meet standards that would be imposed by the county in the platting process, like pavement quality and minimum widths and curve radii to accommodate fire trucks, all of these costs could be delayed until each lot is actually built upon, rather than having to all be on the ground over the whole subdivision at the outset to satisfy platting requirements, well before the first buildings could be built. This would also deliver a “time value of money” benefit. Saving money.
  • Here again, if condominium ownership is not desired, the project could still be developed with conventional lotting, with the drives being platted streets, “just” increasing costs some, not impacting on the water management benefits of the overall concept.
• If there is not a waterline from a Public Water Supply System with sufficient capacity to serve the development close to the property, or if local groundwater does not have the capacity to support further development in the area – the situation over the JWGMZ – a reliable water supply can be provided by basing it on building-scale rainwater harvesting (RWH).
  • This would create a sustainable water supply system that would not draw down the local or regional water supplies, so would not negatively impact on the water environment, such as reducing springflows.
• • Under this strategy, costs would not be incurred to create the water supply for each building until that building is built, as the supply system would be part and parcel of the building construction. This would delay those costs until each building is built, so again delivering a “time value of money” benefit. Saving money.
• • For each building, it would be determined what the “right size” would be for the roofprint – the collection surface for the rainwater supply – and the storage cistern relative to the expected water demand in the building. A “right-sized” system would – based on modeling of an historic period that would cover a severe drought period – provide a large majority, typically 95% or more, of water usage over the modeling period. Water that would not have to be pumped out of the aquifer.
• • The needed roofprints could be provided with fairly “modest” house designs; this concept need not require “mansions” to make it viable. There are many examples of such RWH houses all throughout this region. Building designs can be derived that would most efficiently provide the needed roofprints, and could also incorporate the cisterns within or adjacent to the buildings, so not requiring free-standing cisterns to dot the landscape. A circumstance that some current HOAs deem an eyesore.
• • This overall strategy would include a plan for guaranteeing the provision of any backup supply that might be needed at any given building through a severe drought period.
  • With no wells or waterlines, fire protection would be addressed by installing dedicated fire suppression water tanks, to provide whatever amount of water is deemed to be needed in each situation.
• Stormwater management would be centered on Low-Impact Development (LID) practices, most particularly “green infrastructure” such as rain gardens – engineered bioinfiltration or biofiltration basins – into which runoff from “developed” surfaces would be routed, for both water quality management and to provide some detention storage.
  • This basic stormwater management strategy essentially implements the Symbiosis-style “land treatment” – essentially permaculture practices – to enhance insoak and storage at the expense of quickflow runoff.
• • The overall system may also entail installing BDAs on any headwater draws within or bordering the site.
• • If building-scale RWH is the water supply strategy, the degree of rainwater collection off of the roofs would essentially take those impervious surfaces “out of play” in regard to water quality management, allowing rain gardens to be smaller, and leaving only whatever level of detention is deemed necessary for cistern and rain garden overflows. Saving money.
• • RWH would sequester water that would otherwise be direct runoff from the roofs, that would be covering a piece of land on which in its “native” state a large majority of annual rainfall would have infiltrated. That roof runoff is flow which, without RWH, would largely become quickflow runoff. This avoided runoff is transformed into 100% slow infiltration, once that harvested water, after being used for water supply in the building, becomes wastewater flow that is dispersed in drip irrigation fields.
• • If RWH were not used for the water supply, rainwater catchment off roofs could be used as the water quality management scheme, also integrating in storage to provide additional irrigation water supply around each building, in the manner illustrated in “… and Stormwater Too”. This could be part and parcel of strategies to take irrigation off the potable supply system, as was reviewed in this Waterblogue post, so relieving the aquifer of having to supply that water.
• • By these means, the stormwater management system would hold on the land at least as much rainfall as would infiltrate under “native” conditions. Indeed the amount held on the land could be increased, as is envisioned under the “land treatment” strategy, only allowing runoff to exit the site after the holding capacity of the LID installations were “filled”. This would maintain, indeed enhance, the hydrologic function of the site, making the rainfall-runoff response as “good as” or “better” than what occurred on the “native” site, despite having covered some of the site with impervious surfaces.
  • By a multiplicity of sites managed in this manner, the hydrologic integrity of watersheds could be maintained, indeed restored, so that the land would not be “desertified” by development, rather we’d be maintaining – or enhancing – stream baseflow and springflow in the watershed. In the JWGMZ and environs, over which some (much?) of the land has been hydrologically degraded by past land use practices, these practices would shift the balance to less quickflow runoff – the “flash” hydrology characteristic of Hill Country watersheds – and more insoak, that would become direct recharge or extended stream baseflow. Much of that baseflow may become recharge as it flows over recharge features in streambeds, past which much of the “flashy” runoff would rush.

I also ran this development model by the AI ‘bots, to get a read on whether it would be reasonable to expect that this sort of “hydrologically restorative” development strategy could indeed improve the water yield out of the watershed, in a manner similar to what the ‘bots asserted could be imparted by the various land treatments noted previously. The feedback was quite positive. Observations included:

• To the basic question, can development practices meaningfully shift the balance toward recharge and away from water exiting the watershed via quickflow runoff, the answer was, yes, but only if the development is hydrologically regenerative rather than extractive. That is, developed under the model set forth above.
• While “conventional” development typically exports water via centralized wastewater systems, greatly increases runoff, and increases groundwater extraction, this hydrologically regenerative development model blunts, or completely avoids, all that, through the practices reviewed above.
• This is not water neutral, it is a positive addition to the water yield out of a watershed. We would be effectively “importing” water into the soil that would have otherwise been “lost” downstream.
• This is the only development model that has any chance of being hydrologically restorative in a karst watershed.
• 10-20% of the watershed developed this way would yield noticeable improvement in baseflow stability.
• 30-40% adoption would yield a measureable shift in hydrograph shape and reduction of aquifer stress.
• 50%+ adoption would plausibly deliver a system-level improvement in spring persistence.

There would likely be some consternation among the environmental advocacy community about developing a significant portion of the JWGMZ watershed, but it must be kept in mind that this development entails a degree of land restoration. It might be questioned how valuable it would be to simply “preserve” land that is hydrologically degraded, vs. to develop it under the hydrologically restorative model. And it’s likely to be some time before a significant portion of the watershed would be developed, allowing opportunity to assess the actual impacts, and to adjust the aims and expectations as found to be relevant.

In any case, recalling how this whole discussion started, if any significant portion of the watershed were to be “treated” to enhance insoak as general land management practice, a high-level impact may be attained while actively developing less of the watershed. Bottom line, the overall prospects for positive outcomes appear high.

Though the benefits could be significant, there would be a high hurdle to be surmounted to move practice to this model. As the ‘bot stated it, the obstacles are not hydrologic, they are:

• Regulatory
• Cultural
• Developer inertia
• Financing norms
• Utility business models
• County level governance structures

This model threatens:

• Centralized utilities
• Engineering firms
• Revenue streams
• The “standard practice” template

It is noted that this whole way of proceeding is not exactly new. The suite of strategies set forth above is the same basic “prescription” suggested a couple years ago for the Hays Commons project on the outskirts of Austin in “Moving off top dead center”, to mitigate a development over the Edwards Aquifer Recharge Zone in which the water environment is about to be significantly degraded by applying the “once-through” conventional water management practices. And really also for Mirasol Springs in “If you’re going to call it a vision …”. Indeed, some variant of all this has been set forth as a template for water management on developments for over 2 decades, and the wastewater management aspects of it for over 4 decades.

This is noted simply to highlight that those practices still sit largely idle because those barriers the ‘bot listed do indeed pose a huge hurdle. This is all disruptive to entrenched interests and therefore has been, and will continue to be, difficult to navigate through the objections of “the system”. Indeed, that history shows it seems unlikely that one could navigate through it at all, so one will have to go around it, to put a “shining example” project on the ground that proves the concept would deliver on its promises. But none of that changes the hydrology, the ‘bot stressed, it only changes the adoption curve.

On the plus side of all this, Hays County is in the process of bolstering its “conservation development” standards, and communications to date indicate that the water management strategies set forth above are generally what they have in mind as features of conservation developments. As the basic development scheme needs only plat approval and an OSSF permit from the county, it is not expected that the proposed “shining example” project would encounter regulatory pushback.

Now of course folks will ask what it would cost to conserve land in this manner. We should look at that in light of the overall aim to “preserve” this watershed. The land can of course be put off limits to development so as to retain its positive water management properties, like was touted for Karst Canyon Preserve, or it can be conserved in regard to water yield management by developing in this hydrologically restorative manner. The former would cost money, the latter would make money. So on a purely fiscal evaluation, this is a no-brainer; conservation development wins hands down. Recognizing of course the value of open space to people, so it is not suggested that all land “preservation” be abandoned, but clearly there is an opportunity to hydrologically conserve far more land, funded by the private sector, than we could ever afford to buy for open space dedication.

The real cost question is what is the actual cost efficiency of developing in this manner. Or maybe stated in developer-speak, whether the unit yield relative to the cost would make this model appear to them to be a good deal, the money-saver that it’s asserted above it would be. Land price would of course be a big part of that. The more expensive the land, the greater the unit yield must be, or maybe the higher-dollar the properties must be, for the project to “pencil out”. So could this development model deliver “enough” units? We’ll come to understand how that works out when we do put a project on the ground.

It remains to find the landowner who sees the value in this manner of proceeding, who embraces the land ethic, who wants to leave a land legacy, improving rather than degrading the watershed. A landowner who would choose to develop in this hydrologically regenerative manner, who wants to be the one to set forth the “shining example” project … and maybe break the dam and start us down the road to sustainable water.