This map was produced as part of the Montana Bureau of Mines and Geology study of the groundwater flows in Seeley Lake. The four arrows indicate the identified trajectories of groundwater in 1999.
The Clearwater Resource Council hosted a day-long conference on Sept. 6 focused on watershed hydrology, how water moves throughout the Clearwater Basin, the potential for it to pick up pollutants and how septic systems can play into those processes. Other topics included presentations on invasive fragrant water lilies and shoreline conservation.
Experts emphasized the connectedness of the watershed. Karen Williams, aquatics director with the Clearwater Resource Council, said while much of the focus of the conference was on the lakes in the valley, those lakes don't exist in a vacuum.
"They're part of the watershed, they're integrated in the watershed and in fact they receive a lot of the processes that are happening in the upper parts of the watershed and are integrated, manifested and shown in the lakes," Williams said.
Williams described stream channels as "the plumbing of the watershed," which collects all the runoff and eventually dumps it into the lakes. The Clearwater watershed encompasses 346 square miles, Williams said, and all the water within drains into the Blackfoot River near Greenough. Everything to the east of the watershed drains into the Bob Marshall Wilderness and past Summit Lake to the north goes into the Swan River, Williams said.
Some of that water dumping comes in the form of runoff, which occurs post snow or rainfall and can make its way into the groundwater, remain in the soil, hydrate plants, get stored in lakes or rivers or go back up into the atmosphere. It's all recycled in the water cycle, Williams said.
A study performed by the Montana Bureau of Mines and Geology in 1999 identified four different paths of groundwater flow in the Clearwater Basin. Two paths took groundwater straight into Seeley Lake while two other paths flowed into the Clearwater River.
The plumbing in the watershed doesn't just contain water, but includes sediments, nutrients and pollutants. Pollutants are broken into two categories when considering how they impact a water basin - point source and nonpoint source pollution.
Point source is relatively straightforward - it comes from a visible location, the easiest example being an oil spill. Wastewater treatment plants often have point source discharge permits that allow them to put treated water into rivers. The Clark Fork River once had four wastewater treatment plants - in Butte, Deer Lodge, Missoula and Smurfit Stone - that had discharge permits.
"Nonpoint source is like dark matter, it's just everywhere," Williams said.
It can be picked up from roads with construction sites, agriculture, forestry, septic systems or anything that disturbs the surface and clears the way for runoff to carry it through a basin. Williams said 85% of rivers and streams and 80% of lakes in the country are impaired by nonpoint source pollution.
Montana's Department of Environmental Quality has a program that provides funding to address nonpoint source pollution and it administers total maximum daily load permits, or TMDLs, which give a permit-holder a maximum allowed amount of discharge that still supports water quality for four beneficial uses defined in state law, including drinking water, recreational, aquatic life and agriculture.
DEQ monitors how beneficial uses are upheld with narrative and numeric standards. Numeric standards include the amount of a specific pollutant allowed in a water body that still protects the beneficial uses, Abbie Ebert, DEQ water quality monitoring scientist, said. Narrative standards are "statements of unacceptable condition" in a water body that aim to keep a water body "free from conditions that produce undesirable aquatic life."
During the 2021 legislative session, a bill required DEQ to switch from numeric standards for monitoring nitrogen and phosphorus to narrative standards. Environmental groups along with wastewater treatment managers and the Montana League of Cities and Towns opposed the legislation. In June, according to Montana Free Press, DEQ announced it would no longer move forward with adopting the changes in the 2021 bill.
Ebert also spoke about the life cycles of lakes and how lakes can move through different trophic states from young lakes that are low in nutrients - like Flathead Lake - to older lakes that contain a lot of nutrients and plant life.
"Where humans interact with these natural trophic states is we can speed up this process. We can push a lake into the next trophic status before it's ready to go there, because we as humans input nutrients faster than lakes would naturally," Ebert said.
Charlie Shane, Missoula County land sanitarian, said properly maintaining septic systems, which can contribute to nonpoint source pollution, goes a long way to keep undesirable nutrients or pathogens out of groundwater.
"Protection of you and your neighbors' drinking water supply is extremely important and protection of our water resources whether that be groundwater or surface water is extremely important, and a big part of that in areas that utilize septic is septic systems being well maintained and properly functioning," Shane said. "But if you do it right, they will hold treatment and dispose of wastewater for years to come."
Reader Comments(0)