City of Exeter Wells: Location, Screen Depth and Water Quality

Lithology colour follows whether an interval is a screen target, not grain-size naming. The two browns are materials you would not perforate: dark brown is clay and other confining fine-grained material, light brown is sandy clay and interbedded clay-sand, which is marginal at best. The two blues are screen candidates, sand and then gravel or cobbles, with the darkest blue the most permeable. Note that Well E14W is screened 320 to 535 ft almost entirely in the light-brown class and is one of the system's two weakest producers at 186 gpm, which is the cautionary case for perforating this material. Lithology simplified from handwritten DWR Well Completion Reports and binned at 10 ft; dominant material shown. Verify against the original scans before design use. E9AW lithology above 296 ft is taken from the adjacent E9W log (DWR WCR 77746, 1964); below 296 ft it is unconfirmed until the pilot bore. TW-2 (2026 test hole at the City yard, 700 ft) is plotted from the P&P Test Hole 2 plan coordinate; its lithology log and zone depth intervals have not been issued yet, so its four zone results are shown as dashed markers stacked in zone order, not at depth. Water quality markers span the interval each result actually represents: for production wells that is the full screened section, so a single number is a screen composite, not a reading at one depth. Marker positions shown as approximate were georeferenced from the 2019 Master Plan system map and are accurate to about plus or minus 150 ft. Yield bars: City wells from the 2018 SCE pump efficiency tests; area wells from the airlift or pump test filed on the DWR well completion report. Airlift rates understate what a properly developed production well would make, so hatched bars are not directly comparable to solid ones. Yield per foot of screen divides total yield by total screened footage and assumes it is uniform across all screened intervals, which it is not; treat it as a comparison metric, not a design value. The E9AW bar is the 800 to 1,000 gpm design target, shown at its midpoint. The TW-2 bar (~300) is P&P's field estimate from zone testing, reported at the September 24, 2026 project meeting, not a pump test. Sources: 2019 Exeter Water System Master Plan (QK); DWR OSWCR well completion reports; Provost & Pritchard Exeter Test Well Technical Memorandum, DRAFT 19 August 2025; BSK Associates reports AJC3355 and AJG3959; BSK reports AJH3935, AJI0024, AJI0280 and AJI0527 (TW-2 zones, 25 September 2026); P&P Test Hole 2 plans (14 April 2026); City of Exeter 2024 Consumer Confidence Report.