Summit Engineering designed the septic system for the Spring Creek Elementary School when the school was constructed in the late 1980’s. The septic system, a large volume system, consisted of a 12,000-gallon septic tank, 2 alternating siphon dosing tanks, 5 distribution boxes, 22,000 square feet of leach field consisting of 24 leach lines (4 quadrants), 8 piezometers to monitor effluent levels, and a groundwater monitoring well. Periodic monitoring of the septic system is a permit requirement of large-volume septic systems, and Summit Engineering has monitored the Spring Creek septic system since it was constructed in 1988. Approximately 15 years after the system was put into service effluent was continually noted to be standing in a portion of one of the leach fields. Summit continued to keep an eye on the system and eventually notified the school district, suggesting that they consider constructing an additional leach field to relieve the existing system.
The project scope of work included surveying, mapping, geotechnical investigation, civil engineering design, and preparation of plans, specifications, and estimating documents suitable for bidding and construction. The auxiliary septic system was designed to tie into the existing septic system such that one-half (two quadrants) could be shut off at any time and redirected to the auxiliary system, allowing the original leach field to rest and restore itself. The auxiliary system consisted of 300 feet of PVC sewer line, 4 gate valves, an alternating siphon dosing tank, 3 distribution boxes, a manhole, 8 air vents, 4 piezometers, and a groundwater monitoring well.