Tuesday, November 29, 2016

Drought takes toll on Lehigh Valley streams. Is emergency pending?

Drought takes toll on Lehigh Valley streams. Is emergency pending?

Andrew Wagaman
Contact ReporterOf The Morning Call
Two puddles of water were all that remained last week in an area of the Little Lehigh Creek designated for fly
fishing, downstream from the Wild Cherry Lane Bridge in Lower Macungie Township.
"In my 45 years of fishing this stretch of the Little Lehigh I've never seen it like this," one man commented after the Little Lehigh chapter of Trout Unlimited posted a photo on its Facebook page.
"Now you know where all the holes are," another said.
Always room for some dark angler humor amid stingy skies and an otherwise sober reckoning. The summer heat is gone, so maybe you haven't noticed: the Lehigh Valley and surrounding areas in the Delaware River Basin continue to bear the brunt of a drought spanning the eastern portion of the state.
The state Department of Environmental Protection declared a drought warning Nov. 3 in Lehigh, Northampton, Monroe and Carbon counties. Since then the dry weather has persisted, and groundwater and surface water indicators have taken a turn for the worse.
Officials are now preparing for a drought emergency, which comes with mandatory water restrictions. Environmental advocates are wondering if it's too little, too late.
The Lehigh County Authority will give an update Monday on how the drought is affecting the nonprofit utility's water production.
"We have not seen the kind of decline in water supply that would indicate a problem serving the community," CEO Liesel Gross said last Wednesday. "From an environmental perspective, however, the Little Lehigh Creek is most certainly experiencing a severe impact of this drought."
The Commonwealth Drought Task Force will discuss changes to its drought declarations Wednesday, according to the Nov. 23 DEP drought report.
Per the drought warning, residents and businesses in Lehigh, Northampton, Monroe and Carbon counties have been asked to reduce their water usage by 10 to 15 percent. Another 30 counties are under a drought watch, where residents are asked to conserve water by 5 percent.
Mandatory water restrictions only go into effect when the state declares a drought emergency.
Last week, groundwater measurements taken at the U.S. Geological Survey observation well in Upper Macungie Township had fallen to 80 feet below the surface for the first time since 2002 — the Lehigh Valley's last drought emergency. Normal conditions at this time of year are between 60 and 70 feet.
Groundwater fell more than 85 feet below the surface in 2002, according to USGS data. But 80 feet falls in the "drought emergency" zone, too.
Easier to see: disappearing surface water. According to a USGS surface water gauge in the Lehigh Parkway in Allentown, the Little Lehigh's rate of flow is at about 40 cubic feet per second; the median is about 70 cubic feet per second.
The Monocacy Creek in Bethlehem is arguably in worse shape, with flow rates having fallen to 12 cubic feet per second last week. That nearly reached a 50-year low and indicates drought emergency conditions. The median is about 41 cubic feet per second.
The DEP has acknowledged that surface water and groundwater are at "extremely low levels" in the Lehigh Valley. But low enough to declare a drought emergency? Not yet.
"A county's drought status could change from warning to emergency if the public's health and safety are endangered and there's a threat to natural resources that creates problems greater than what county resources alone can handle," Deborah Klenotic, DEP deputy communications director, said in statement Wednesday.
Michael Siegel of Lower Macungie Township believes the Lehigh Valley was headed toward that "greater threat" months ago.
The former hydrologist called for water restrictions in April after noticing that the Little Lehigh watershed experienced negligible groundwater recharge despite the record-breaking 32-inch snowstorm in January.
Restricting water use this summer would have been "very productive" in protecting the base flow of the Little Lehigh, he argued. Now the base flow is essentially gone.
"Should the base flow go underground, the upper reaches of the Little Lehigh Creek environment will be destroyed, and it will be years before this high-quality stream will be returned to normal," Siegel wrote in June.
He also believes the creek's flow rate is worse than indicated. He claims the removal of the Robin Hood dam in Allentown in 2013 has distorted the measurements taken by the USGS' surface water gauge on Lehigh Parkway.
The brown trout living in the Little Lehigh eat aquatic insects and other macroinvertebrates in the streambed, said Scott Alderfer, president of the local Trout Unlimited chapter. When the streambed goes dry, the fish food dies.
"There's a reason the Little Lehigh has such a high-quality classification, so it's very disturbing to see any portion of the creek take such an extreme hit from a drought like this," Alderfer said.
Droughts also exacerbate stream pollution, said Percy Dougherty, a Lehigh County commissioner and retired geology and physical geography professor. Take the occasional sanitary sewer overflow, when fecal coliform and other bacteria contaminate the creek. If the stream flow is low, the bacteria are more concentrated and can do more damage to the stream ecology.
Streams that are on limestone bedrock such as the Little Lehigh are more susceptible to droughts than others, Dougherty said. Limestone has more access points — cracks and crevices — where the bacteria can get in.
Dougherty would like to see LCA install more gauges measuring the effects of deep well pumping on the groundwater levels, particularly during a drought.
"With the monitoring we have now, I'm not sure if we have a really good handle on what's happening out there during low flows," he said. "Of course that costs extra money, but groundwater recharge data and water quality data are important."
LCA, to the consternation of some, deepened two Lower Macungie wells in 2010 to provide additional water capacity to its system. But that expanded capacity is not being used, Gross said. In fact, the water withdrawn from the two wells combined makes up less than 3 percent of the total water volume supplied through the Allentown and LCA systems.
During a 2001 drought, LCA was pumping about 5 million gallons per day of groundwater versus 3 million gallons today. Little Lehigh groundwater levels fell lower than they have this year, yet the surface water flows were not affected that year.
Why the creek has dried up this time "requires significantly more study and observation," Gross said.
The DEP determines its drought status based on precipitation and soil moisture in addition to groundwater and surface water levels. In Lehigh County, both precipitation and soil moisture remain at more moderate "drought watch" levels. In Northampton and Carbon counties, every indicator except soil moisture has reached "drought emergency" levels.
awagaman@mcall.com
Twitter @andrewwagaman
610-820-6764
Cut back on water use
DEP encourages all citizens to take steps to reduce their water use:
• Run water only when necessary. Avoid running the faucet while brushing your teeth or shaving, or letting the shower run for several minutes before use.
• Check for household leaks. A leaking toilet can waste up to 200 gallons of water each day.
• Run dishwashers and washing machines only with full loads.
• Replace older appliances with high-efficiency, front-loading models that use about 30 percent less water and 40 to 50 percent less energy.
• Install low-flow plumbing fixtures and aerators on faucets.
LCA meeting: noon Monday, 1053 Spruce Road, Wescosville