MCD dams storing water more often than ever before

By Mike Ekberg, manager of water resources monitoring and analysis

MCD flood protection dams are storing water more often than at any other time since the dams were completed almost 100 years ago. That’s because the Miami Valley’s climate is getting wetter. Can the flood protection dams handle more rain?

A rising 30-year average precipitation
Average annual precipitation in the Miami Valley for the 30-year period of 1951 to 1980 was about 37 inches a year. Average precipitation for the last 30 years (1991 – 2020) has climbed to almost 42 inches a year—a nearly 14 percent Increase.

Average precipitation increased for every month except August. Average precipitation for the months of January, April, May, June, July, September, October, November, and December increased by more than 10 percent. October showed the largest increase in average precipitation—more than 30 percent.

With increased precipitation comes increased runoff and higher river flows. When river flows become high enough to be a flood threat, our flood protection dams go into action and begin to store water. When any one or more of our dams begin to store water, we call that a “storage event.” Storage events at each of the dams are recorded separately. So if all five dams are in storage at the same time, it is counted as five storage events. The storage event ends at each dam when that dam is no longer holding back any water.
 
Waters stored behind dams more frequently
MCD tracks the number of storage events that occur each year. The following chart shows the number of storage events that have occurred during each full decade since the dams were completed in 1922. You can see how the number of storage events has climbed throughout the decades of the 1990s, 2000s, and 2010s. Prior to the 1990s, no single decade had more than 200 storage events. The number of storage events in the last three decades all exceeded 200, and storage events for the decade of the 2010s exceeded 300.  

More frequent large storage events
Increasing frequency of storage events at MCD dams is one thing. What about the size of those storage events?

The answer seems to fall in line with simple odds. All other things being equal, the more storage events there are, the greater the chance of having really large events.

We rank storage events based upon the total storage volume of water held behind our five dams. The following chart shows the number of events by decade that rank in the top 100 largest storage events. You can see that 32 of the top 100 largest events took place in the last 20 years. The decades of the 2000s and 2010s each had 16 storage events that ranked in the top 100. Only the 1950s comes close to this number. That decade produced the largest storage event since the MCD flood protection system was built—the January 1959 event.

MCD flood protection system is resilient
The climate of the Miami Valley is changing and getting wetter. Flood risk is increasing. Fortunately, the MCD flood protection system is well designed to respond to these changing conditions in the Miami Valley.

The system was designed to withstand a very large event—the 1913 flood event plus 40 percent more runoff (which is the equivalent of 11-14 inches of rain over three days). The January 1959 event was the largest storage event since the completion of the flood protection dams. The 44.8 billion gallons of floodwater the dams held back used only 16 percent of the five dams’ total storage capacity. That means 84 percent of the capacity has never been used but is there if we need it.

The MCD flood protection system is resilient—based on design, capacity and performance. Resiliency is a good thing to have in a rapidly changing world.

Learn more about the flood protection system.

Regional trails draw worldwide attention

By Angela Manuszak, Special Projects Coordinator

Many everyday items that make life easier were invented in the Dayton region. The airplane. The pop-top can. The cash register. Dayton is also home to some pretty amazing, more natural creations, too, namely, our rivers – and the hiking and biking trails near them. And while our trails don’t get the same attention as the airplane or the cash register, our regional trails are about to get noticed in a big way.

The American Trails’ International Trails Symposium heads to the Dayton region, May 7-10. The ITS is a biennial symposium that brings together the worldwide trails community to experience regional trails and advocate for the economic and environmental power of trails.

But what’s so special about our rivers and trails?

With 340 miles of trails to explore, this region boasts the largest, paved trail network in the country

Contiguous land ownership

MCD owns extensive and contiguous riverfront land in cities along the Great Miami River as part of its flood protection system. It also preserved floodplains at each of its five dry dams. Upstream of each dam are vast tracts of land meant to flood occasionally so downstream cities don’t. MCD’s first chief engineer, Arthur Morgan, persuaded the MCD Board of Directors to open thousands of acres of the “retarding basins” to the public.

Today, each dam’s forested greenspaces are wrapped with hiking trails, traversed by bike trails, dotted with picnic areas, then splashed with river launch ramps – all managed in partnership with county park districts, especially Five Rivers MetroParks.

In the 1970s, a grassroots effort to build a paved, connected trail on MCD’s riverfront property led to the first major segment of trail – an 8-mile loop on both banks of the Great Miami River in Dayton. While flood protection remains the highest purpose of the land, trails are a compatible use that has transformed our region. The Great Miami River Bike Trail now has a total of nearly 80 miles completed, and new sections will be constructed before 2020. Other trails – built by MCD partners and colleagues — radiate like bike wheel spokes from Dayton in every direction.

The Buckeye Trail is one of many hiking trails throughout the region.

Recognition
Every year the trail network’s fame grows. MCD’s trails:

  • Host part of the North Country and Buckeye trails.
  • Have been named National Recreation Trails.
  • Are designated to carry part of US Bike Route 50 across the state.

Connect several sites of the National Aviation Heritage Area.

The Great Miami, Stillwater and Mad rivers, along with Greenville, Buck and Twin creeks are the only nationally designated water trail in Ohio and one of only 22 in the country. The Great Miami, Stillwater and Mad rivers also are a state designated water trail.

State and national designated water trails

Our rivers are getting plenty of attention, too. Last year, the Great Miami, Mad and Stillwater rivers along with Greenville, Buck and Twin creeks were designated the first and only National Water Trail in the state of Ohio. The national water trail designation by the U.S. Department of Interior is given only to those water trails that are exemplary. The Great Miami, Stillwater and Mad rivers also are state-designated water trails.

Soon the world will know
With all of the amazing trails nearby, no wonder American Trails chose the Dayton region for its 2017 ITS. We are proud to join the list of celebrated trail cities that have hosted this conference in the past, including: Portland, Oregon; Tucson; Chattanooga; Austin; and Orlando. We hope you will join us for the symposium or one of the related events open to the public. Go to americantrails.org to learn more.