WATER VOLATILITY IN ACTION
Significant rains have recently inundated Texas, bringing a welcome relief from the immediacy of drought conditions – particularly in the eastern portion of the state. These storms, a result of a stagnant air mass combined with high pressure over the southeastern United States and a persistent southerly flow of moisture up out of the Gulf of Mexico, spread across the Southern Plains from the eastern half of Texas, through Oklahoma, and into southern Kansas.1
These storms, and the resulting flooding, are an example of the increasing volatility in the water delivery mechanisms that is contributing to our water vulnerability. As precipitation patterns become more intense, our reservoir-based supply-side management programs will not be as effective, particularly during precipitation events that continue well after the point of ground saturation. At that point, it becomes very difficult for the ground to absorb water, resulting in increased runoff that cannot be captured.
The National Weather Service in Fort Worth calculated that the Texas-wide May rainfall volume was over 35 trillion gallons, an amount that would cover the entire state in water eight inches deep.3 Despite this volume, the Texas Water Development Board (TWDB) indicates that the state’s reservoirs sit at 83.1 percent of capacity, having only received approximately 3 million acre-feet – approximately 1 trillion gallons – in May 2015.4 Where did the rest of the water go?
THE HOUSE ALWAYS GETS PAID
Texas is suffering a multi-year drought that has resulted in a significant soil moisture deficit. Data published by the Texas Soil Observation Network (TxSON) indicates that in mid-2014, there was a soil moisture deficit of approximately 40 million acre-feet, or approximately 13 trillion gallons.5 This data also suggests that reservoir replenishment lags soil moisture recovery. That is, until the soil moisture deficit has been satisfied and a measure of soil saturation achieved, reservoirs do not fill. It is critically important, however, that the saturation of the upper levels of the soil not happen too quickly or the available water will cause rapid, flash flooding and the water will not have time to replenish the soil moisture deficit.
This phenomenon occurs routinely during heavy, intense storm events like tropical storms and hurricanes. Professors Vasubandhu Misra (Florida State University) and Satish Bastola (Georgia Institute of Technology) examined historical rainfall records and calculated soil moisture-based drought indices for 28 watersheds across the southeastern United States and found that tropical storm and hurricane rainfall resulted in negligible changes in soil moisture, primarily as a result of rapid saturation and subsequent runoff.6
This can be seen in NASA’s GRACE data where the surface moisture has yet to penetrate to the shallow groundwater regions. In effect, the consequences of the short, intense, volatile rainfall that occurred in Texas in May 2015 was saturation of the upper layers of soil, which allowed some water to flow into reservoirs, but had limited impact on shallow groundwater moisture levels. As a result, instead of finding its way into our reservoirs or recharging our aquifers, the majority of the 35 trillion gallons will simply find its way into the watercourses of the state and ultimately discharge to the Gulf of Mexico.
IT AIN’T OVER ‘TIL IT’S OVER (AND IT’S NEVER OVER)
While the majority of Texas is now out of drought conditions8 and the TWDB indicates that the state’s monitored reservoirs are 83.1 percent full, the spatial distribution of this storage is definitely skewed to the east portion of the state. For instance, in the panhandle region, reservoir storage is at 10.5 percent9 and in the Rio Grande region reservoirs are less than 50 percent of capacity.10 The United States Drought Monitor estimates that over 218,000 people11 remain affected by drought conditions in Texas, despite the rain.
Clearly water supply management will be a continuing requirement in these areas, and continued effort will be required to ensure water sustainability. The fact that portions of Texas may be drought-free for the moment does not make it drought-resilient nor mean that the danger is over.
There is a tendency for rain to obscure the underlying reality of water supply. By not heeding the evidence and employing foresight in the continuing volatility of our water supplies, we run the risk of diving head first into what the National Drought Mitigation Center has called the hydro-illogical cycle.
With amplified volatility in the water cycle, there will be an increasing frequency and extent of drought and flooding conditions – and these will become more difficult to predict with great certainty. With increased stormwater comes additional pressure on municipal infrastructure and finances. Municipal stormwater compliance costs will increase, and cities may be driven to billion-dollar consent decrees to protect receiving waters. Further, water supply projects cost billions of dollars and take several years to decades to complete.
That is why it is critical that we begin to live within a sustainable volume of water and invest in water efficiency tools like advanced metering infrastructure (AMI), customer presentment and technologies that can provide revenue assurance for utilities. To address these extremes and survive financially, municipalities must maximize their collectible revenue, while minimizing the operational costs of their existing infrastructure in order that they may invest in what surely will be an increasing demand for smarter water management.
HEDGING YOUR BETS
Utilities and municipalities must plan for both drought and flood. When water is short, we need to maximize the efficiency of our supply. When there is excess water, we must be able to invest in stormwater mitigation infrastructure. At each end of the spectrum, finding and assuring the revenue necessary to accomplish these goals is a paramount requirement.
This means that utilities must:
- Reduce water demand to ensure sustainability during drought conditions by adopting AMI systems and customer presentment tools that enable conservation;
- Adopt near-real time data systems that allow for a better understanding of demand and provide the basis for operations efficiencies and extending the life of existing assets through pressure control and peak flow reduction;
- Engage customers in understanding how their actions impact sustainability;
- Deploy revenue assurance tools and systems to allow for sustained financial operations and investment in infrastructure such as stormwater management infrastructure; and
- Employ data architectures that allow for the rapid adoption and deployment of distributed sensors and technologies to allow for a better understanding of the water situation within the community.
FATHOM provides the platform on which to achieve these requirements. FATHOM finds and preserves revenue; FATHOM reduces demand allowing existing supplies and infrastructure to be operated over a longer time period; and FATHOM is an open-architecture data platform that allows sensors and technologies be rapidly deployed throughout a community.
With FATHOM, utilities can prepare for future volatility, while maximizing their operational and financial efficiency today.
4http://waterdatafortexas.org/reservoirs/statewide (accessed 1 June 2015)
5Texas Soil Observation Network (TxSON), http://www.beg.utexas.edu/txson/
6Florida State University. “Summer tropical storms don’t fix drought conditions.” ScienceDaily. www.sciencedaily.com/
releases/2015/05/150527150948.htm (accessed June 1, 2015).
7http://drought.unl.edu/nasa_grace/GRACE_GWS.png, and http://drought.unl.edu/nasa_grace/GRACE_SFSM.png (accessed 5 June 2015)
12http://www.waterdatafortexas.org/reservoirs/statewide/recent-conditions.png (accessed 5 June 2015)