Spring rains needed to refill Lavon Lake, other major suppliers

Springtime rains have yet to bring relief to the area's most carefully watched water source, Lavon Lake, which remains significantly below its full pool level.

What that means for Frisco and surrounding cities that are part of the North Texas Municipal Water District is that without some changes, Stage 3 water restrictions may not be enough to get through the hot summer months of high water usage.

Frisco Public Works Director Gary Hartwell said two factors will keep the area out of the substantially more severe Stage 4 restrictions: help from mother nature in the form of soaking spring rains and a continued effort to conserve the existing water supply.

"If in the next month or two [the Lavon Lake water level] takes a nosedive, [NTMWD officials] are going to have to consider Stage 4," Hartwell said. "This is the first time I can remember that we are this dependent on spring rains. We've got to have them."

Although the pipeline to allow the district to use Lake Texoma water while circumventing zebra mussels will be online beginning in May or June, it will have little effect in the near future.

Rainfall outlook

The substantial rainfall needed to refill area reservoirs may not happen, said David Finfrock, chief meteorologist for NBC 5 Dallas-Fort Worth.

As of March 15, 2014 is one of the driest starts to any year in 116 years of record keeping, he said. He said as of mid-March, there had been only 0.84 inches of rain so far this year in the area, which is more than 5 inches below the normal rainfall. Frisco borders between moderate drought and severe drought, according to the U.S. Drought Monitor.

"It appears that we are going to remain drier than normal through the spring and summer," Finfrock said. "There is some hope for next fall and winter, though."

The meteorologist said an El Nio watch was posted mid-March and most climate models agree the wetter weather pattern will develop by fall.

"If [El Nio] does indeed occur, then we could anticipate above-normal rainfall for the fall and winter months," he said. "Unfortunately that doesn't provide any relief for the upcoming summer."

Finfrock said reports suggest 2 inches of rain would ease the North Texas drought, but that amount of rain would only allow for crops to grow normally, not for runoff that would fill lakes.

"What we really need is a protracted rain that soaks the soil, followed by a 5- or 6-inch rain so that we see tremendous runoff, which would raise lake levels many feet," he said. "Like my predecessor and mentor Harold Taft used to say, 'The only way to end a drought is with a flood.' There's a lot of truth to that statement."

Stage 4 restrictions

Lavon Lake was at 479.73 feet as of March 28, nearly 13 feet below the full level. The level that would trigger Stage 4 restrictions is about 475 feet, but there are other factors taken into consideration before going to Stage 4.

The NTMWD is required to give a 30-day notice to its member cities before putting Stage 4 restrictions in place. Those restrictions would include banning the use of sprinkler systems and only allowing hand watering for up to two hours once a week.

Denise Hickey, spokeswoman for the water district, said water models are evaluated monthly for worst-case scenarios, including lowest inflows, highest evaporative losses, highest consumption and whether cities are meeting water-use reduction goals to decide when Stage 4 is likely to be implemented.

She said the reservoirs have so far received better than worst-case reports.

"With that, it pushes the change for Stage 4 further into the future. But again, drought continues to persist and no one knows how long it will last or when rains will be plenty to provide runoff into the reservoirs."

Also helping the water district to stay in Stage 3 is the purchase of 60 million gallons of water per day from the Dallas water supply.

The district has been purchasing water from Dallas since May 2013 and has an agreement in place through May 2016, with an opportunity to extend it to 2020.

Lake Texoma pipeline

The 46-mile, $300 million pipeline constructed from Lake Texoma to the Wylie water treatment plant will allow the district to use Lake Texoma as a water source. The lake has not been used as a water source since 2009 when zebra mussels, which multiply rapidly and can cause environmental damage, were discovered.

However, having access to that source is not the short-term answer to the water shortage, Hartwell said.

While Lake Texoma makes up 28 percent of the NTMWD's water supply, the lake's water is high in salt, which requires it to be blended with other sources, Hartwell said.

"Obviously,the lower the level is in Lake Lavon, the less Texoma water they can blend," he said.

Hartwell said just because the pipeline is finished doesn't mean it will increase the level of Lavon Lake.

"It's welcome, but it's not the cavalry," he said.

Water supply

Hartwell said residents have asked repeatedly whether there will be enough water to support Frisco's continued growth. His answer is yes, provided conservation is taken seriously—and if there are not extended years of unprecedented severe drought.

"If we go to Stage 4 restrictions [within the next few months], it will be because people across the district are overusing sprinkler systems," he said.

Hartwell said the city of Frisco has saved 1.6 billion gallons of water since June 2013 when it went into Stage 3 restrictions, and he said he has heard no complaints from residents that yards suffered as a result of the watering restrictions.

Using data from the Frisco weather station, city officials recommended watering only 17 weeks out of the year in 2013—a fact residents need to take note of, he said.

"We have overused water for so long it has become the norm," Hartwell said. "We've got to change that norm."