Community-Driven Success: A POA's Approach to Rehabilitating Lake Louisa Dam
Lake Louisa Dam, located six miles north of Louisa, Virginia, is owned by the Blue Ridge Shores POA and regulated by the Virginia DCR as a significant hazard potential structure. The dam consists of a 25-foot-high, 600-foot-long zoned earthen embankment impounding a 3,450 acre-feet reservoir, with a concrete auxiliary spillway on the west abutment and a pipe and riser system as the principal spillway. Flows from the reservoir enter the North Anna River and eventually Lake Anna. The dam had a history of seepage, voids beneath the chute slab, and concerns about embankment performance due to soft soils and potential internal erosion, resulting in a “poor” condition rating by DCR. In August 2022, the POA contracted Schnabel Engineering to design a replacement auxiliary spillway, filter diaphragm, drain system, and other safety improvements. The POA self-funded the rehabilitation, and providing a cost-effective solution that met DCR dam safety criteria was the primary goal for this project. The design team demonstrated that additional spillway capacity was not needed to pass the required spillway design flood and designed a filter diaphragm and drain system mitigating large excavations in the dam. A phased stream diversion and water control approach minimized disruption to the fish population, provided 25-year storm protection with a sandbag cofferdam, and reduced construction costs and schedule impacts. Schnabel also helped the POA find a qualified bidder in a challenging construction market. The rehabilitation required coordination and approval from multiple stakeholders, including the POA, Louisa County, DCR, and VA DEQ. Construction began in September 2023. Despite challenging weather conditions during much of the construction period, including Hurricane Debby and, less than three weeks later, an overnight thunderstorm producing 7 inches of rain, the project was completed within the POA’s budget in September 2024. The project resulted in a “satisfactory” condition rating and allows for continued long-term, safe operation of the dam and lake for the POA. This presentation will highlight the POA’s approach to the project, the dam’s deficiencies, which are not uncommon for Virginia dams constructed in the 1960s, and the creative design solutions to meet both state dam safety criteria and the POA’s needs and budget. We will also touch on the POA’s funding strategy and community involvement.
Author Bio
Corey Schaal is a Senior Engineer at Schnabel Engineering’s dams group in Greensboro, North Carolina. With a Master of Science in Civil Engineering (Geotechnical) from Virginia Tech and a Bachelor of Science in Geological Engineering from the University of Mississippi, Corey brings almost 10 years of experience in geotechnical and dam engineering. Corey specializes in geotechnical analysis and design of dam rehabilitations. He also has significant experience with risk analysis, dam assessments, flood modeling, and emergency action planning. Corey has served as the engineer of record on numerous projects in North Carolina and Virginia and is also registered as a Professional Geologist in North Carolina.
