Keoka Lake is both watershed and spring fed. You can feel the springs feeding the lake as cold spots when swimming and you can see the broad watershed as evidenced by the many streams which feed into the lake. There are six streams that run most of the year and literally dozens of rivulets that rush with spring melt water.
On the other hand, Keoka has only one outlet – just to the west of the Keoka Beach Campground. The outlet pours into City Brook (historically it was often referred to as Mill Brook) which feeds Bear Pond, Bear River, Long Lake, Brandy Pond, Songo River, and ultimately, Sebago Lake.
There were three small mill ponds downstream from Keoka’s outlet. These mill ponds were fed by City Brook, which runs from Keoka along Waterford Road and down through “The City” (South Waterford). Mill owners who relied on Keoka water for their power depended primarily on the Whitney Dam. This dam impounded a three-quarter acre mill pond just downstream of the current Keoka outlet. The Whitney Dam appears to have been built on the brook itself in or just prior to 1808. This dam was named for Captain Abraham Whitney, a native of Stow, MA and a Revolutionary War soldier who settled in Waterford in 1805, erecting a gristmill, and possibly a sawmill. This dam was originally a granite slab and earthen dam that was upgraded several times during its lifetime – ultimately to a poured concrete structure. It was still functional into the 20th century, as the housing and turbine from the Waterford hydroelectric generator are intact on top of the main dam. The ruins of the Whitney Dam are clearly still visible along City Brook.
Once upon a time, Keoka’s outlet did not have a dam. The lake was unimpounded. We have been unable to locate definitive records about when the original dam was built. However, Prentiss Kimball, Waterford’s current plumbing inspector and jack of all trades, born in 1930, and hired to repair the dam in 1972, believes that a group of mill owners along City Brook worked together to place the large granite slabs that comprise the first impoundment of Keoka, sometime in the late 1800s. This would have allowed some control of water flow levels for the benefit of the mill owners downstream.
The Mason Dam was built at the mouth of City Brook. It was constructed from granite slabs with glacial till used as chinking. The level of the newly impounded lake rose four to five feet from that observed prior to the dam. The Mason Dam also allowed the water level of Keoka to be more readily controlled than prior to its construction. And like any earthen dam, it required periodic maintenance.
In the early 1950s, Keoka users noticed that summer water levels were seldom maintained to their satisfaction. Indeed, wear and tear on the slab and earthen dam had rendered it unreliable for controlling Keoka’s water level. By 1952, there were no downstream mills relying on water power any longer. To address the dam issue, a group of “summer folk” commenced a project that encased the granite slabs in reinforced, poured concrete. The work resulted in a dam structure that is 110 feet along the lake, with a 3 foot wide sluiceway (controlled by an oak gate), and a 14 foot wide spillway – a failsafe to prevent lakefront flooding. The concrete structure was more reliable, lower maintenance, and allowed better regulation of a target lake level, while ensuring that South Waterford had enough flow to provide for domestic use and fire-fighting.
By 1971, some of the retaining wall constructed in 1952 was suffering from undermining by wave action, so a newly-created KLA-sponsored a project to reinforce and rebuild that section. For years, Glen Merrill, whose camp abuts the dam, maintained the gate – opening and closing as needed – with brute strength and a lever against the force of the rushing water. He faithfully cleared out debris which caught in the mouth of the sluiceway and ensured that all was working well. The State of Maine inspects the Mason Dam on a regular basis and has repeatedly declared it to be a “low risk” dam. The oft-disputed ownership of the dam was cleared up with title research in 1989, and KLA received a 99 year easement/lease on the structure from owner, Moria Mason.
Then in 2004, the wooden gate was replaced by a modern, steel gate structure which could be controlled by a screw gear mechanism – a vast improvement from the prior situation. Kilton Tabor, assisted by his father, Andy, took on the planning and execution of the dam gate replacement as Kilton’s Eagle Scout project, sponsored by KLA. Fifteen years later, we are still getting great service from the dam gate mechanism.
In early 2021, Charles Mason, son of Moria Mason, donated the dam and the property it sits on to the Keoka Lake Association. Today, a loose-knit band of volunteers, yes, still including Glen, maintain the flow and set the gate to achieve a desired lake level. There is some weather awareness necessary and a lot of guesswork. However, they find there is nothing they can do to make it rain when the water level is too low. And in recent years, that has been a persistent problem.