Flowing Artesian Well With Uncertain Annular Seal Near a Wetland
A driller completes an 8-inch steel-cased well in fractured volcanic rock. Total depth is 180 ft, casing is set to 40 ft, and the open hole runs from 40 to 180 ft. The well flows at an estimated 30 gpm at land surface after completion. No grout returns were observed. The driller used a bentonite slurry but is unsure whether it reached the annular space behind the casing. A wetland is 100 ft away, and a spring feeds a neighbor's stock pond 500 ft downslope. The owner wants to cap the well and pipe the flow to a stock tank. The driller proposes a rubber packer at 30 ft and a concrete cap. The well report has not been filed; the driller says flowing wells are exempt from reporting.
1. Evaluate the casing and annular-seal adequacy for this flowing artesian well.
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The casing and seal are questionable. Casing to 40 ft may not be seated into competent rock, and the absence of grout returns means the bentonite may have been washed away or never placed around the casing. In a flowing artesian well, water can move upward behind the casing and create erosion, surface leakage, or a pathway to the wetland. A rubber packer at 30 ft and a concrete cap control the visible flow but do not prove the annulus is sealed. The driller should treat the well as unsealed until the annular space is verified and grouted. The well report should describe the uncertainty honestly rather than claiming a completed seal.
2. What steps would you take to control the flow and complete a proper seal? Include sequencing.
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Control the flow first. Install a temporary valve or packer so the flow can be diverted or shut in without breaking the formation, then evaluate whether the casing can be extended or seated into competent rock. Attempt to establish circulation and place a continuous cement-bentonite grout from the casing shoe to land surface, using pressure grouting or a packer if the flow prevents normal placement. Verify returns and grout volume. If the annulus cannot be sealed because of the flow, the driller may need to drill a relief hole, use a specialized grouting method, or decommission the well. After sealing, install a permanent sanitary cap and valve. Do not rely on a concrete cap alone to resist artesian pressure.
3. What reporting and water-right issues arise, and is the claim that flowing wells are exempt from reporting correct?
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The claim is not correct. The driller must file the well report for a flowing well just as for any other well, and the report should document the flow rate, casing, grout, and control measures. Reporting is separate from water rights. Piping the flow to a stock tank may or may not qualify for a stockwater exemption, but the driller should not assume that any flowing well is exempt. If the water is not beneficially used, the well should be controlled or sealed to prevent waste. The owner should confirm with OWRD whether the proposed stockwater use needs a permit or qualifies for an exemption, and the driller should not file a report that describes the well as exempt from regulation.