The Cherrydale Lake Dam is an existing dam on Beaverdam Creek near Woodbridge Road in Hanover County, Virginia.  Hillis-Carnes was hired by the County of Hanover Department of Public Works to provide subsurface exploration and geotechnical engineering services.  Our work focused on both the current stability of the dam and options for improvement as required to improve stability to an acceptable level and deal with any seepage issues if needed.  The work was performed in 3 phases:  field exploration program, laboratory soil testing, and engineering evaluation analysis.  The field exploration program consisted of drilling three borings along the crest of the dam to depths of about 10 feet into strong natural soils.  Soils were sampled continuously to the maximum depth explored using standard penetration test (SPT) methods.  To help establish seepage characteristics through the dam we installed piezometers in each borehole and read these piezometers after the water levels in them had stabilized.  All soil types were visually classified by a geotechnical engineer, and classification tests were performed on recovered soil samples. Once the field exploration and laboratory testing programs were complete, we determined the pertinent soil and groundwater parameters from the data collected in the field and laboratory programs.  A full geotechnical engineering report was prepared and issued to both the Client and Engineer.

In 2021, Hillis-Carnes provided Geotechnical Services during the improvements made to the lake.  Key improvements included diverting road drainage, providing subsurface embankment drains, and repairing the existing concrete riser structure.  The subsurface exploration program consisted of two Standard Penetration Test (SPT) soil borings.  Another geotechnical engineering report was prepared and issued to both the Client and Engineer.

In 2022, Hillis-Carnes provided Construction Materials Testing and Inspections for the new sanitary sewer installed next to the retrofitted dam.  We also observed the construction of several wetland benches in the new lake, installation of several concrete ditches, dam improvements, and the new articulated matting cover over the dam.