DAM/SPILLWAY RIP RAP PROJECT

A new capital project is about to begin at Chantilly National as early as next week. As many of you may be aware, the dam has come under some scrutiny from the state in recent years. The dam, built in the late 1950's, has never been permitted. Due to it's small size and age a permit has never even been required. But, federal regulation changes, enforced by the state, went into effect in 2012. These changes to the regulations now place several new requirements, mostly related to safety, on the dam.

It seems a bit extreme but the options presented by these new regulations were to either bring the nearly 60 year old dam into compliance with modern standards or remove the dam completely. I am sure I do not have to tell you how important the dam is to the golf course. It is vital, without a dam there would be no lake resulting in no water to irrigate the golf course. The only viable option was to begin the permitting process.

This was a known issue when ClubCorp purchased Chantilly and at that time they made a commitment to find a solution. It has been a long road over the last 4 or so years navigating the legal requirements, inspections, submitting countless documents and reports and a host of engineering test including a bathymetric survey, topographic survey, hydrologic/hydraulic analysis, dam breach analysis and inundation mapping, to name a few. Truly, the list of requirement and steps and tests seemed almost endless and ClupCorp has spent a small fortune to bring the dam into compliance and ensure the lake and dam are both safe and legal.

At this point all of the engineering tests and reports have proven that the dam meets all of the requirements and the Operation and Maintenance Permit for the dam has been granted. Additionally, the dam has been rated as "low hazard" meaning it is both safe and offers a very low risk of damage to life and property IF it were to fail. This is all great news and, with continued annual inspections and reporting, the dam (and lake) will be allowed to remain at Chantilly.

There is one bit of bad news. During this process it was discovered that the emergency spillway that parallels #11 and crosses under the first bridge at #12 is in desperate need of repair. This spillway is the emergency or secondary spillway meaning it only engages during or subsequent to a flood or heavy rain event. It is working properly in terms of draining the lake as designed but the problem is it is eroding at an ever increasing rate. Portions of the the spillway channel are on bedrock and are not of concern. The issue is at the end closest to the lake. There is a head cut that is 2 or 3 feet below the normal standing pool level of the lake. If not addressed, the erosion will continue to advance until reaching the lake edge and permanently drain the lake by several feet. This cannot be allowed as it would both look horrible and, more importantly, significantly reduce the irrigation water reserve.

The fix is fairly simple. A portion of the spillway will be regraded, a liner installed, and then over one thousand tons of new rip rap will be installed. The images below show the scope of the work. The area within the red circle is where the new rip rap will be installed. Virginia Waters and Wetlands, a local company based in Vint Hill, VA, has been contracted to do the work. VA Waters specializes in wetlands restorations, stream bed work, etc. and are uniquely qualified to perform the work.

The contractor has already been on site several times doing some preliminary work but they expect to deliver equipment and break ground as soon as next week. There are certainly a lot of unknowns and weather is always a factor but the project is expected to be completed within the next 6 to 8 weeks.