Gage Slide Explanation
The picture below is an example of what you will see. Refer to it to follow the explanation. Please note the current water level reading on the slide is just below the title.
In this example, the level recorded by their electronic gage is 1279.73.
The State is using the elevation of 1279.80 as the crest level. So, in this example, the level is .07 which is almost 1/10th of a foot below crest. Water levels have always been recorded in tenths of a foot. To convert, a tenth of a foot is equal to one and one quarter of an inch – 1.25 inch or 1 and ¼ of an inch.
The spillway is not level, it slopes from west (highest) to east (lowest) about 2-3 inches. So water will go over the east side of the spillway first. The Canal Corporation has determined we are at crest when water runs over the FULL face of the spillway so even if water is running over the spillway, it will show we are not at crest. It’s minor but want everyone to understand when you see it reported we are not at crest but water is running out that is the reason.
Regarding the rest of the slide, this is what the engineers have modeled using projected draw down increased rates this September based on average rain fall data. Looking at the green vertical dotted line on the left of the graph, drawdown will begin Sept 1 and is projected to be down the 10 feet by November. This is only a computer projection. The amount of rain has everything to do with this projection. If we have large amounts of rain throughout September, not only will the Reservoir level not drop as fast, but due to potential flooding downstream, the withdrawl rate will have to be lessened which will extend that 10 ft November mark further to the right on the bottom of the date line.
Same for the right side of the graph with the green triangle. This shows the PROJECTED filling of the lake when the repairs can safely take the increased head pressure from higher levels. The left (leg) of the triangle shows filling to begin approximately April 2020 which would include diverting water from the middle branch of the Tiougnioga into the Reservoir via the south end feeder. As of now, they are intending to build a new temporary inlet structure where our inlet gates are located and are no longer usable.
The right side (leg) of the green triangle models the filling of the Reservoir withOUT diversion. As can be seen, following left (diverting) leg to the top to the brown horizontal line which is crest level shows we will crest by June 1st, 2020. Without diversion, the right leg of the green triangle shows we would crest by November 1, 2020……just in time to draw it down (just a little humor considering this option would not allow for a great 2020 summer). Again, THIS is projections based on historical data.
Bottom line, weather, rain and snow or lack thereof has more control over this project than any other aspect. The Canal Corporation has done everything possible to complete this work within the time frame, including some night work, to complete this project safely for all concerned and still get us a summer of water in 2020. Keep your fingers crossed.
Sorry for the length of this but I find it hard to explain graphs with words and not be able to point to them to explain. Kathy and myself will have more on this at the 4th of July meeting.