Projects

Project Description

Well No. 10, has had ongoing problems with sand and gravel intrusion through the well screen, ultimately creating operational and maintenance problems when the sand and gravel settles out within the existing ultraviolet (UV) reactors. Well No. 10 is a 12-inch diameter well approximately 104.5 feet deep, with 30 feet of screen. Historically, Well No. 10 has been excellent in terms of water quantity with flows ranging from 1500 gallons per minute (gpm) to 2100 gpm. Recently, the Town has been unable to fully utilize Well No. 10 (reduced pumping) due to the sand and gravel intrusion.

The overall intent of the project is to identify a replacement well site on the Town’s existing property with an anticipated capacity of 1500 gpm, inclusive of permitting and design/bidding/construction phase services. The existing property is limited in area (approximately 1.24 acres) and is constrained by the Hunt River to the south and its associated 200 foot riverbank wetland buffer zone. The entire property is essentially within the 100 year flood zone as currently mapped by FEMA.

CEI developed a detailed test well program to determine the optimum location of a future replacement well. This test well program involved innovative sonic drilling which provided a continuous core sample which clearly defines the stratigraphy of the aquifer. CEI determined that there were 2 viable locations for a future permanent well.

CEI recommended placement of a 12 inch test wells drilled to approximately 90 feet in depth and that this well be pumped to determine potential permanent well capacity and drawdown. The 12 inch well was pumped over a three-day period and provided over 600 GPM with only a 5 foot length of well screen.

Subsequent testing was done to determine detailed well-design parameters for the permanent well. As presently proposed the permanent well will be a 16 inch diameter well drilled to a depth of 88 feet with 25 feet of well screen. The constructed well will have a 24 inch gravel pack sized to prevent the migration of sand into the well screen. The potential yield of the well will be between 1000 and 1500 GPM based on the final construction and pump test.

CEI has provided complete oversight services today and will be providing design, bidding and construction services for the final integration of the well into existing facilities.