Reports on the effects of climate change are popping up daily in the media. Most of the time, though, stories involving historic drought, wildfires, flash flooding and excessive heat come from parts elsewhere in the U.S. and worldwide.
It may be easy to think that climate change is happening “out there,” but not here, or at least not yet.
Locally, though, the Nine Mile Creek and Riley Purgatory Bluff Creek watershed districts have a front-row seat in witnessing the effects of climate change.
Nine Mile Watershed District manages water resources draining into its namesake creek from about 50 square miles of the south-central region of Hennepin County, including parts of Eden Prairie and five other cities.
Riley Purgatory Bluff Creek Watershed District does the same on 50 square miles of land draining into the three creeks in its name. The district includes parts of Eden Prairie and six other cities spread over Hennepin and Carver counties.
At Nine Mile Creek, Randy Anhorn, district administrator, and Gael Zembal, the district’s education and outreach coordinator, pointed to more variable water levels caused by greater variability in precipitation and warming winter temperature lows.
More variable water levels are caused by more frequent cycles of drought combined with fewer but more intense rainfalls.
According to Anhorn and Zembal, this has led the National Weather Service (NOAA) to adjust their measure of 100-year rainfall events from 5.9 inches (established in 1961) to 7.2 inches more recently.
Rain events like this lead to flooding, which would cause storm sewers to back up and shoreline erosion, damaging residential and commercial properties and harming water quality from runoff related to fertilizers and pesticides, they said. With that comes more frequent and persistent algae blooms, harming fish, waterfowl and swimmers at the beach.
Anhorn pointed out that a blue-green algae advisory was issued for Lake Cornelia in Edina earlier in August.
With rising low temps in winter, Zembal said there is more snowmelt. With that comes higher concentrations of salt as the water from snowmelt enters the streams, wetlands and lakes in the watershed.
Terry Jeffery, the district administrator of the Riley, Purgatory Bluff Creek Watershed District, concurred that climate change has led to greater variability locally in precipitation and drought. He pointed out that in 2015, a 100-year rain event occurred, causing storm sewer backups in Chanhassen and major traffic arteries to become flooded.
Jeffery stated that the district has experienced severe drought this year, with creeks in several areas having run dry.
Currently, he said Bluff Creek isn’t supporting any fish, and other fisheries are in danger of collapse. Groundwater in the local watersheds is being depleted. Complicating matters is that groundwater sources come from outside the districts, so it becomes even more important for businesses and residents within the districts to reduce their groundwater use.
With the trend toward more cycling between droughts and floods, Jeffery said the district expects that more funding from property taxes will be needed to update street and sewer infrastructure and more wetland restoration.
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