The Miami Conservancy District is a river management agency operating in Southwest Ohio to control flooding of the Great Miami River and its tributaries. It was organized in 1915 following the catastrophic Great Dayton Flood of the Great Miami River in March 1913, which hit Dayton, Ohio particularly hard. Designed by Arthur Ernest Morgan, the Miami Conservancy District built levees, straightened the river channel throughout the Miami Valley, and built five dry dams on various tributaries to control flooding. The district and its projects are unusual in that they were funded almost entirely by local tax initiatives, unlike similar projects elsewhere which were funded by the federal government and coordinated by the U.S. Army Corps of Engineers.
The 1913 flood has been ascribed[ by whom?] in part to the 1912 eruption of Mount Katmai and its daughter volcano Novarupta in Alaska.[ citation needed] In one of the greatest recorded volcanic events, Novarupta emitted enough fine ash into the atmosphere to block sunlight and cool the climate of the Northern Hemisphere that winter.
Located near Englewood, Ohio, Englewood dam is the largest of the dams maintained by the district. It regulates the flow of the Stillwater River into the Great Miami River. It consists of 3,500,000 cubic yards (2,700,000 m3) of earth, is 110 feet (34 m) high and stretches 4,716 feet (1,437 m). U.S. Route 40 crosses the top of the dam. The dam can contain 209,000 acre feet (258,000,000 m3) of flood water over 6,350 acres (26 km2). It was constructed in 1919 and consists of as much earth as the Great Pyramid of Giza.
Located near Germantown, Ohio, Germantown Dam regulates the flow of Twin Creek into the Great Miami River. It consists of 865,000 cubic yards (661,000 m3) of earth, is 100 feet (30 m) high and 1,210 feet (370 m) wide. The dam can contain 73,000 acre feet (90,000,000 m3) of flood water over 2,950 acres (11.9 km2) (12 km²). It was constructed in 1920.
Located near Fairborn, Ohio, Huffman Dam regulates the flow of the Mad River into the Great Miami River. It consists of 1,665,000 cubic yards (1,273,000 m3) of earth, is 65 feet (20 m) high and spans 3,340 feet (1,020 m). The dam can contain 124,000 acre feet (153,000,000 m3) of flood water over 7,300 acres (30 km2).
Located north of Piqua, Ohio outside the village of Lockington, Ohio, Lockington dam regulates the flow of Loramie Creek into the Great Miami River. It consists of 1,135,000 cubic yards (868,000 m3) of earth, is 69 feet (21 m) high and spans 6,400 feet (2,000 m). The dam can contain 63,000 acre feet (78,000,000 m3) of flood water over 3,600 acres (15 km2) (15 km²). It was constructed in 1919.
Located near Vandalia, Ohio, Taylorsville Dam regulates the Great Miami River. It consists of 1,235,000 cubic yards (944,000 m3) of earth, is 67 feet (20 m) high and spans 2,980 feet (910 m). When full, the dam would inundate 9,650 acres (39.1 km2) (39 km²). It was constructed in 1919.
The Miami Conservancy District (MCD) actively promotes and develops recreational amenities throughout the Great Miami River Watershed. MCD owns and/or maintains an extensive recreation trail system (nearly 34 miles) throughout Montgomery County. The trail system is part of a network of 340 miles of multi-use, paved path  that connect Dayton east to Xenia and near Chillicothe and London, south to Franklin, west to near Greenville, and north to Piqua. 
MCD builds boat ramps to encourage recreation on the Great Miami River Watershed waterways. MCD also offers river recreation maps to the Great Miami, Mad and Stillwater rivers which make up the national and state-designated Great Miami River Watershed Water Trail – the largest water trail system in Ohio. The trail collectively offers 291 miles of waterway accessible to recreational boaters, fishermen and wildlife watchers.
Low dams: MCD owns four low dams. Only Two-mile Dam in Hamilton is part of the flood protection system. The low dams create a pool of water upstream of each dam for recreation, including boating and fishing. The cities of Hamilton, West Carrollton, Moraine, and Dayton and Montgomery County pay an assessment for MCD to maintain the dams.
RiverWalk: The Dayton RiverWalk runs along the levee-top between the Main Street Bridge and the Monument Avenue (Dayton View) Bridge on each side of the Great Miami River. The total length of the lighted, crushed gravel walkway including the two bridges is about 2 miles. The walkway is easily accessible from the end of either bridge. The Miami Conservancy District controls the land where the walkway is located and maintains the facility for the City of Dayton.
All of these projects were constructed and are maintained by funds separate from flood protection or groundwater assessments. Assessments to cities – as well as grants and other revenue sources – pay for the construction and maintenance of MCD recreation amenities.
- Miami Conservancy District Homepage
- The Miami Valley and the 1913 Flood, State of Ohio, Miami Conservancy District, Arthur E. Morgan, Chief Engineer, Technical Reports Part I, 1917
- What a Dam Sight (Geocaching.com)
Miami Conservancy District (ASCE)