US Army Corps of Engineers
Huntington District

History

Interim Risk Reduction Measures

Interim Risk Reduction Measures (IRRM) are measures taken to reduce the probability of failure or the consequences of failure.  Interim measures are a short term approach to managing Dam Safety risks while long-term solutions are under development.  Dover Dam's IRRMs were developed and evaluated between November 2006 through May 2007 at the district level.  The "final" IRRM Plan is under development now and will be followed by Independent Technical Review and subsequent Division and HQ USACE concurence.

Although there are many IRRM, a few of the select ones include: 

Development of an Interim Operating Elevation (IOE):  The project IOE is a target pool elevation used during management of high water events.  Depending on the circumstances, as the pool elevation approaches the IOE, the discharge (or outflow) is increased incrementally in an effort to prevent the IOE from being surpassed.  As the pool equals the IOE, the Huntington District will attempt to equalize the discharge to the inflow into the pool in order to maintain the IOE and prevent further increases in pool elevation.  The Huntington District has defined, the IOE for Dover Dam in it's current condition as elevation 907', or 9' below spillway.  This IOE serves as a guide.  The Huntington District may operate to higher elevations based on the Factor of Safety curves, hydrologic conditions or other factors at the time.  Additionally, as new conditions for the dam are discovered, the District may adjust the IOE.

Anchor Dam Using Existing Foundation Drains:  Initial analysis shows that installing and stressing steel bars in the existing foundation drains result in an overall increase in the safety of the dam by 2 to 3 feet in pool elevation.  The district has recently completed the design and analysis development for this IRRM.  Construction is expected to begin prior to the end of 2007 and be complete mid Spring 2008.

Perform Emergency Exercise:  A Dam Safety Exercise (DSE) was conducted for the Bolivar and Dover Dams on December 18, 2006 that allowed the District to identify and raise awareness of Dover and Bolivar dam stability and downstream flood impacts.  The exercise revealed many lessons learned, allowing us to verify strengths in some areas, and showed others that need some improvement.

Update Flood Inundation Mapping:  Flood inundation mapping for a "spillway design flood" with and without failure for Dover Dam was completed in 1983.  All affected county Emergency Operations Centers already have hardcopies.  Updated inundation maps for Tuscarawas County are currently being developed to include inundation zones resulting from lower discharges from Dover Dam other than a "spillway design flood."

Frequently Asked Questions

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 1.  QUESTION:  Will the Dam Fail?

ANSWER:  Unlikely prior to the implementation of repairs and improvements.  As referenced in the Dover Dam Safety Assurance History, with the installation of the Interim Anchors, the dam is safe through pool elevations up to and including 909', or 51 feet on the Dover dam gage.  Pools above 909' do not necessarily mean imminent dam failure, rather concerns regarding the possibility of dam failure increase as pool elevations rise above these thresholds.  Note that an extreme rain event or series of events is required to raise pool elevations to 909' and beyond.  January 2005 was the worst storm event since the dam was built 70 years ago, and the dam can manage storms of similar magnitude.

 

2.  QUESTION:  Will the Dam still Provide Flood Protection (aka Flood Damage Reduction)?

 ANSWER:  Yes.  The dam will still reduce downstream flood damage by reducing peak flows.  The dam will continue to provide downstream flood damage reduction against rainfall events similar to what has historically occurred since the dam's completion in 1937.

 

3.  QUESTION:  Will We get Flooded More Often?

ANSWER:   Not likely.  Although the possibility exists, there is a low likelihood of experiencing downstream inundation worse than experienced in January 2005 for the period prior to completion of the final dam improvements.  The Corps will operate the dam within a safe range of pool elevations.  In order to do so, during extreme events, the Corps may be required to release water above the current downstream flood control levels.

 

4.  QUESTION:  Are Dam Improvements Planned?

ANSWER:  Yes.  Planning is ongoing.  Pending continued funding, the current schedule of construction is anticipated to begin in 2010 and should be fully rehabilitated and operational between 2013 to 2015.

 

5.  QUESTION:  Who will Pay for Dover Dam Improvements?

ANSWER:  The U.S. Army Corps of Engineers will pay for 96.55% of the construction costs of the repairs and improvements to Dover Dam.  Subject to executing a project cooperation agreement (PCA), the Muskingum Watershed Conservancy District will pay 3.45% of the study costs and construction costs of the repairs and improvements to Dover Dam.

 

6.  QUESTION:  What is Being Done to Reduce Risk Prior to the Final Dam Improvements? ANSWER:  The Corps is evaluating and implementing various Interim Risk Reduction Measures (IRRM).  The "final" solution is to stabilize the dam using a system of steel cable anchors.

 

7.  QUESTION:  Once Improvements Are Made, What's the New Likelihood of the Dam Failing?

ANSWER:  Once repaired, extremely unlikely throughout a person's lifetime.  The dam will theoretically be able to withstand a 10,000 year storm event without failing.   This translates into about a 0.01% chance any given year.

 

8.  QUESTION:  Who owns Dover Dam?

ANSWER:  The Dover Dam is owned by the U.S. Army Corps of Engineers.

 

9.  QUESTION:  Who operates the Dover Dam?

ANSWER:  The Dover Dam is operated by the U.S. Army Corps of Engineers, Huntington District.

 

10.  QUESTION:  Who Maintains the Dover Dam and How is the Maintenance Funded?

ANSWER:  The Dover Dam is maintained by the U.S. Army Corps of Engineers, Huntington District.  The maintenance for the Dover Dam is 100% federally funded.  These funds come from the Operation and Maintenance (O&M) budget of the U.S. Army Corps of Engineers, Huntington District.