Inside the tower you are likely to find Dick Gilbert who has been watching over the spillway for 24 years. Dick and a team of 4 others keep a 24x7 watch on computer systems and security cameras to make sure that everything about the spillway and dam is running smooth.
The Control Tower also serves as the dispatch center for the Reservoir Patrol, all the operators are 911 trained and have communication links to neighboring police, fire, and other emergency services. For any emergency you should dial 911 but for after hours water or sewer problems (on PRV property) the tower should be notified at 601-992-9703.
A critical function of the tower is to control the massive gates that allow water to pass through the spillway. There are 10 steel gates that are 40 feet wide and 20 ft tall. The two center gates are used for normal discharges and the others are used during times of heavy rains. Below is a shot of the monitor that controls the gates, notice the row of boxes along the top of the screen, each box represents a gate. If you enlarge the picture by clicking on it, you can see that all the gates are closed except the center one which has been raised 3 inches. This picture was taken Tuesday afternoon when the discharge rate was 256 cubic feet per second. One cubic foot per second translates to 7.48 gallons per second.
The engineers at the PRV use a computer model to assist them in determining the discharge rate. The software, developed by the Vicksburg Corps of Engineers, considers water inflow, rainfall amounts, and rainfall predictions to calculate how much water should be released. Output from the computer combined with human experience determines the gate settings.
Regardless of inflow, the PRV never drops below a discharge rate of 240 cubic feet per second. During summer dry spells the discharge may exceed the inflow, that situation combined with natural evaporation can cause the lake to drop about a tenth of a foot every 3 days.
Here are a few other facts about the spillway.
- The gates can be moved mechanically if no electrical service is available.
- The tower can be powered by an on-site generator that can operate for 1 week without refueling. The backup generator is tested weekly.
- The maximum output of the spillway is approximately 170,000 cubic feet per second.
- The maximum discharge during the 1979 flood was 140,000 cfs.
- The reservoir supplies Jackson's O. B. Curtis water treatment plant through pipes that run under the dam.
- The Nissan Plant receives all of its water from the reservoir after being processed by the O. B Curtis water treatment plant.
- The control tower has computer systems that monitor the residential water and sewer systems owned by the PRV.
- There are 9 security cameras along the dam and boat launches, all monitored in the tower.
- The target elevation of the lake in the summer is 297.5 feet above sea level and 296 in the winter.
- If a discharge gate ever fails a barrier can be installed in front of it that would block the water flow so that repairs could be made.