A very common question this time of year is, “When are you going to start raising the water level?” The short answer to this question is, “hopefully by April 7th, we will begin raising the water level.” A much longer answer is below.
As I wrote to lake residents last July, there was and is a problem with leakage through the dam. As required by RI Department of Environmental Management (RIDEM), we contracted with a Professional Engineering firm with expertise in Dams (specifically Pare Engineering Corporation) to do a detailed study of the dam around the area of leakage (just south of the Gatehouse). In October a test well was drilled into the dam, and the water level was monitored inside the dam as the water level dropped in the lake. Leakage was also monitored at the site. From the analysis of the drill borings and actual water level data (both inside the dam and lake level), Pare Corp created a model of the dam's structure and made recommendations as to what corrective actions CPWL needs to take to bring the dam into compliance with RIDEM.
The first step is to cut all trees down in the study area, the theory being that the leaking water is following roots as they wind through the dam. Eventually, the roots will need to be pulled out as much as possible without disturbing the integrity of the dam, but that is a project for winter 2022-2023. Cutting trees down now will allow the roots to degrade a bit, making them easier to pull out next winter. Most likely the downstream (opposite the lake) side of the dam will need to be regraded, with a slope much less than it is now. That is likely a project for 2023-2024 depending on the cost and funding available.
Because of possible damage to the dam, the trees must be cut when the water level is low. The final report (available on the website, cpwl.org) from Pare Corp was delivered to us (and RIDEM) on March 17. RIDEM approved the cutting of trees in concept, but there were hoops to jump through. Based on RIDEM regulations, trees on the dam and up to 15’ from the toe of the dam may be removed without a permit (‘toe’ is defined as where the dam embankment meets the natural grade of the land). Our problem is that several of the trees (and likely the ones causing the problem) are more than 15’ from the toe of the dam. Over the last couple of weeks, we, with the help of Pare Corp have appealed to an exception mentioned in the regulation but were unsuccessful. Bottom line…we need to have a permit.
The application process for the permit requires a bit of work from us and some from Pare Corp. Both pieces should be submitted to the DEM by Thursday afternoon 3/31. DEM has said they will expedite the permit application so that we should have it within about 48 hours of the completed application.
Once that is done, the trees will be cut, and then we will be raising the lake level.
Looking forward to the first boat ride of the season!
Phil Viall, for the Dam Committee.