Lake Chillisquaque (also known as Montour Lake) is a lake and reservoir in Montour County, Pennsylvania, in the United States. It has a surface area of 165 acres. The lake is situated on Middle Branch Chillisquaque Creek, which it is named after. Nearby communities include Danville and Washingtonville. The lake has an elevation of above sea level and is up to deep. It has several coves, including Goose Cove, Heron Cove, and Jellyfish Cove. The lake is dammed on its southern side by the Lake Chillisquaque Dam, which is long and high. The metals with the highest concentrations are calcium and iron. Nonmetals such as nitrogen and phosphorus are also found in the lake. It experiences agricultural runoff as well.
Lake Chillisquaque is owned by Pennsylvania energy company Talen. It was constructed in 1972 and was originally created to serve as a supply of cooling water for the Montour Power Plant (a purpose which it still serves), but has also come to be used for recreational purposes. Approximately 200 bird species have been observed on or near the lake and more than 50 species of waterfowl pass by the lake during migration. It is also inhabited by numerous species of fish, some of which are stocked by the Pennsylvania Fish and Boat Commission. Various trees, shrubs, and herbaceous plants live in the vicinity of the lake as well. The main recreational activities on or near Lake Chillisquaque include fishing, boating, and hiking. The lake is also surrounded by the Montour Preserve, a nature preserve.
Geography
Lake Chillisquaque is located on Middle Branch Chillisquaque Creek, in Anthony Township. However, other streams feed into the lake as well. It is north of Danville and north of Washingtonville. The lake can be accessed via Pennsylvania Route 44 and Pennsylvania Route 54. The nearest road is Preserve Road/State Route 1006. The lake has an elevation of . With a surface area of 165 acres, the lake is the largest of 82 bodies of water in Montour County. Lake Chillisquaque is the only reservoir in Montour County. Lake Chillisquaque is surrounded by forested hills and agricultural land. The Muncy Hills are situated to the north of the lake.
Large parts of Lake Chillisquaque are fairly shallow. Most of Heron Cove is less than deep and a large area near the lake's boat ramp is approximately deep. The deepest parts of the lake, near the lake's dam, are deep. Lake Chillisquaque has a number of coves, including Heron Cove and the nearby Jellyfish Cove. Goose Cove is another cove on the lake. It is located in the lake's northwestern section. There are numerous other smaller coves and bays. Numerous objects, including tire reefs and cement blocks, have been placed in Lake Chillisquaque to increase its suitability as a fish habitat. There are also basking platforms for turtles on the lake.
Dam
Lake Chillisquaque is dammed by an earth-fill dam known as the Lake Chillisquaque Dam. Located on the southern side of the lake, the dam is long and high. The dam is wide at its highest point and the top of the dam forms an access road. The inner part of the dam is a silty clay material, while the outside is made of weathered shale.
According to the Montour County Multi-jurisdictional Hazard Mitigation Plan, a major failure in the Lake Chillisquaque Dam could cause damage to several nearby communities, such as Strawberry Ridge and Washingtonville. It could also result in a decrease in the output of the Montour Power Plant, causing a brownout in the area. A severe failure of the dam is considered by the Multi-jurisdictional Hazard Mitigation Plan to be the most dangerous threat to Montour County.
Hydrology
The water temperature of Lake Chillisquaque ranges from to in the summer. The specific conductance of the lake ranges from 135 to 202 micro-siemens per centimeter. The lake's pH is between 6.6 and 9.3. It is a dimictic lake. The concentration of suspended solids in Lake Chillisquaque ranges from less than 2 to 58 milligrams per liter. The concentration of water hardness is between 54 and 78 milligrams per liter. It experiences agricultural runoff due to the presence of large tracts of agricultural land near the lake.