River levels, leadership on the rise in South Dakota

Farm Forum

Increasing precipitation in South Dakota is helping focus attention on the Big Sioux River as more water means more floods and more pollution.

So more than 100 people gathered Thursday in Brookings for the Third Annual Mayors Big Sioux River Summit started a few years ago by Sioux Falls Mayor Mike Heuther.

The summit featured more than a dozen different speakers, but state climatologist Dr. Dennis Todey relayed the most important information.

The climate is changing, Todey said, choosing to focus on statistics rather than speculative causes.

Annual precipitation in South Dakota has increased 15 percent during the past 100 years.

He noted that in the East Central South Dakota region, which essentially runs from U.S. Highway 212 to Sioux Falls and U.S. Highway 281 from Huron to the Minnesota border, has been particularly wet.

“We are breaking records by huge amounts,” he said, noting that the long-standing annual precipitation record in Brookings was 33 inches, until 2010 when it shot to 40 inches.

“That is the average for the state of Illinois,” he noted.

The state is seeing increasingly large events, noting the August downpour that dropped 4-8 inches in one hour and flooded southern Sioux Falls.

Statewide between 1961 and 1970 the state had one rain station record a 6-inch rain and nine stations record a 5-inch rain.

From 2006 to 2015, three stations had eight inches, four stations had seven inches, seven stations had six inches and 16 stations had five inches.

That has huge implications for public safety infrastructure as well as runoff from cities and agricultural fields, he said.

Additionally, he said, precipitation is falling at different times. Throughout measured history almost all floods have occurred during spring snow-melt events. Now much more precipitation is occurring in late summer and fall.

“That presets the spring conditions,” he said.

All of those events are leading to more water in the Big Sioux River.

Much of that water is carrying pollutants, primarily from agricultural fields, and as a result most of the river does not meet federal pollution standards.

In a discussion following his presentation, Todey suggested that engineers use the high end of the recommended range in designing stormwater infrastructure into developments or agricultural systems. “The extremes cause a great amount of the problem.”

He also said the state needs to expand its monitoring system, whether that is weather, pollution, or flood related.

“Something we don’t do well is monitor,” he said. “We don’t know what is out there.”

Increasing the focus on the Big Sioux River, whether it is flood or pollution related, was Heuther’s motivation for starting the summit.

“We all are accountable,” he said. “We all have to make a contribution.”

Heuther’s focus on the Big Sioux River, along with the recent formation of a Sioux Falls based group called Friends of the Big Sioux River, is good news.

Sioux Falls with its large population base can play an important role in what has been a decades-long effort to clean up the river, which runs from north of Watertown to its confluence with the Missouri River near Sioux City.

Fixing the identified pollution sources in the Big Sioux water shed basin is beyond the state’s financial resources, so convincing people to change lifestyles and business practices is essential to creating cleaner water.

Heuther, along with other panelists, identified buffer strips both in urban and rural settings as a relatively inexpensive way to clean the water before it enters rivers or lakes.

Numerous success stories were showcased in various breakout sessions, and Heuther committed the city of Sioux Falls to committing “buffers, buffers, buffers.”

He also noted how important it was to build partnerships between city residents and the agricultural industry.

Most of all, he said it was important to create more leadership in the efforts to improve the state’s water quality. Based on the diverse group of people in attendance, leadership and precipitation are on the rise.