31 Jul 2020

Edward MacDowell Lake celebrates 70th year commemoration

 July 31 marks the 70th anniversary of the completion of the U.S. Army Corps of Engineers, Edward MacDowell Lake Dam. The project was completed in 1950 at a cost of $2,014,000 and is named after the late composer, Edward MacDowell. The dam, located on Nubanusit Brook in Peterborough, east of Keene, provides flood protection primarily to Peterborough. The project also provides flood protection to the downstream communities of Hancock, Bennington, Antrim, Deering, Hillsboro, and Henniker, all located on the Contoocook River.

31 Jul 2020

Public invited to comment on planned autumn releases from Rathbun Lake

In 2016 in response to stakeholder input, the Corps of Engineers revised its operating guidance for Rathbun Lake. The new guidance allows for an annual opportunity, every autumn, for the lake to schedule a release of water to benefit state and privately managed conservation and recreational areas downstream in the Chariton watershed. This release of water will not exceed 2,700 cubic feet per second from Rathbun Dam and would be sustained for no longer than 3 or 4 days, excluding ramp up and ramp down.

31 Jul 2020

Virtual public meetings set for Collier County study

The U.S. Army Corps of Engineers and Collier County, Florida, its nonfederal sponsor, have released the Collier County Coastal Storm Risk Management Draft Integrated Feasibility Report and Environmental Impact Statement.

30 Jul 2020

PUBLICATION NOTICE: Erosion Thresholds and Rates for Sand-Mud Mixtures

Abstract: Differences in erosion behavior of non-cohesive and cohesive sediments are widely recognized. In many natural environments, sand and mud are not completely separated and occur as mixtures. Significantly less research has been conducted on the erosion behavior of sand-mud mixtures compared to the separate treatment of sand and mud erosion. Sedflume erosion experiments were conducted on sand-mud mixtures with varying mud content to define the relationships between mud content, critical stress for erosion (τc), and erosion rate. Sand-mud mixtures were prepared with three mud sources: (1) non-swelling clay (kaolinite), (2) swelling clay (kaolinite/bentonite), and (3) a swelling, natural mud from the Mississippi River. Test results showed that critical shear stresses of the mixed sediments departed from that of pure sand with mud fractions on the order of 2% to 10%. Peak τc was observed between 30% to 40% mud content, with swelling muds achieving a ten-fold increase in τc while a five-fold increase in τc was measured for kaolinite. Additionally, this study demonstrated that the introduction of small amounts (≤5%) of mud to sand reduced erosion rates by a factor of 10 to 100. This observed abatement of erosion rate has implications for the use of dredged materials in civil and environmental engineering projects.