City staff reviewed groundwater alternatives July 1 and said wells influenced by surface water (groundwater under the influence of surface water, sometimes called GWI or “gooey” wells) and directional or horizontal wells beneath lake and river bottoms are technically possible but carry permitting, treatment and production uncertainties.

Why it matters: Staff said GWI wells can be near rivers, streams or lake edges where the water table is shallow and is directly connected to surface water; those wells are subject to stricter TCEQ regulations, require sanitary protection from floodwaters and often require additional permitting, engineering and water‑treatment plant modifications. Staff cautioned there is no guarantee on production rates and multiple wells may be needed to meet municipal demand.

On horizontal wells and wells drilled under riverbeds, staff said those approaches depend heavily on local bedrock fracturing and that production zones may be confined and unpredictable. Staff noted horizontal wells have not been extensively investigated in the local area, that they would probably require TCEQ permitting, and that pipeline and easement infrastructure would be necessary to move water back to the treatment plant.

Staff also described past local well results: city wells drilled in February 2011 produced modest yields—one behind the dog pound at 120 feet produced about 35 gallons per minute; another well had 40 gpm but ran dry during a 2014 pump test; two other wells were plugged. Staff said production rates have generally trended downward after repeated droughts.

Treatment and water‑quality issues were highlighted. Staff said some granite formations may contain naturally occurring radioactive materials that would need filtration and that wells near the golf course have shown elevated salts requiring desalination or abandonment. Staff emphasized that mixing groundwater with existing surface water supplies can create compatibility issues that require additional treatment adjustments at the plant.

Public exchange: Several residents suggested testing horizontal drilling under the lakebed as a lower‑cost alternative to dam raising. Staff and residents debated the technical tradeoffs: residents argued a horizontal well is effectively a different “straw” into the same reservoir and can be drilled nearer to town; staff cautioned lack of guaranteed production and potential need for many wells, plus pipelines and easements. Staff also said that if a well is truly groundwater (not surface water), LCRA jurisdiction over diversion would not apply, but GWI wells are subject to different regulatory limits because of the surface‑water influence.

Ending: Staff recommended continued study and noted drilling, treatment and pipeline costs could be significant; they encouraged targeted engineering investigations before committing to a drilling program and said permitting, water‑quality testing, and design would be necessary preconditions.