Glass Half Empty: addressing reservoir water waste

Brown is the new green. Burgundy blotches cover Santa Clara county on drought watch maps. A hotline even allows you to report that pesky water-wasting neighbor.

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And so we forge ahead. Another year of drought. Another year of meeting the stringent county goals of water usage reduction.

But what if, at the same time we were told to keep our showers short and our taps tightened, our conservation efforts were undermined by billions of gallons of usable water being drained from our reservoirs?

The Mirage

California has a history of releasing water from its reservoirs in winter to leave room for runoff and prevent flooding. However, when up to 40% of a reservoir’s water is emptied into SF Bay without rain to fill it, we are at risk of dry reservoirs for subsequent months.


While the reservoir capacity restrictions seem practical in theory, ultimately, county residents are more concerned with the threat of dry reservoirs in the summers due to unnecessary drainage than with floods that never come.

Lessons Learned

January 1st, 1997. As millions of Californians eagerly welcomed the new year, the largest flood in the state’s recorded history dampened their spirits. According to the California Department of Water Resources  (CDWR),  “warm moist winds from the southwest blowing over the Sierra Nevada poured more than 30 inches of rain onto watersheds that were already saturated by one of the wettest Decembers on record.”

The consequences were brutal.

Despite the damages of the floods themselves, most important was the control measures taken to prevent reservoirs and dams from overflowing at a time when reservoirs seemed likely to overflow (CDWR). With less rain following the climactic start to the year, controlled releases channeled water downstream and restored the reservoirs to safe capacities.

Yet sometimes, the exact opposite might happen. Reservoirs that were once overflowing and contributing to flood damage to the state dipped to dangerously low levels after a summer of heavy water consumption, the same year.

Nearly 20 years later, the question remains: Is there a safer and more informed way to both prevent flooding in times of immediate crisis, as was the case in 1997, but also to avoid long-term threats in times of drought, as we see today?

Informed Action

In response to the dilemma, UC San Diego is working on a system of  forecast-informed reservoir operations (FIRO) to give four to five days notice before the storms that are typical during El Niño so that reservoirs are not emptied without probable cause. Given that premature draining of reservoirs has lead to low lake levels and drought conditions in the past,  Screen Shot 2016-08-30 at 6.53.42 PMdespite similar El Niño conditions, the FIRO team hopes to use long-term forecasts to manage the retention and release of water.Screen Shot 2016-08-30 at 6.49.04 PM

 

FIRO will use data from watershed monitoring and general forecasting to generate optimal times and conditions for release of water on a case-by-case basis. Thus, resource exacerbation crises like those during the drought two decades ago that left reservoirs waiting for nonexistent flooding are avoided.

Sophomore Lucy Huang also believes that beyond the obvious environmental perks of forecast-informed operations, there are financial benefits to the system as well. “It makes sense that we should look at weather patterns to base our decisions and weigh the damage,” Huang reasoned.

On the Home Front

While UCSD is taking large-scale efforts to create a statewide system of forecast-informed reservoir management, an exclusive interview with Santa Clara Valley Water District (SCVWD) employees reveals that similar mechanisms are being employed locally.

Screen Shot 2016-08-30 at 6.53.34 PMIn contrast with the exclusively forecast-dependent approach UCSD hopes to apply to water districts across California, SCVWD studies the local ecosystem to minimize any adverse consequences of water release.

Shaikh, a civil engineer, describes how much water we start with and how much we can release, an important factor in sustainable resource management. SCVWD studies also agree that the technology developed by UCSD provides a useful supplement to these local practices currently employed by the district.

“It’s great that both the district and UCSD are being proactive,” Huang adds. “After crises ranging from flooding to drought, their long-term actions to prevent more damage is more effective than continuing to act in response to damage.”

After discussion with the state director of natural resources, MVHS AP Environmental Science teacher Andrew Goldenkranz feels that the reservoir initiatives are a positive step.

“The operations system is promising,” Goldenkranz acknowledges. “You can move water between reservoirs, like from smaller to larger ones, to further eliminate draining of reservoir water into, say, the San Francisco Bay, as has been done in the past.”

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It remains questionable as to how effective draining is. However, it is clear that more informed operations will both bolster community sentiment and allow for better management of the state’s water supply.