City staff presented a package of options July 1 to increase the city’s firm water supply, saying the proposals would involve new permitting, engineering and major capital costs. The discussion covered continuing dredging and bathymetric surveys, temporary “flashboards” to raise existing dam heights, potential dam‑raising work, a new off‑channel reservoir or a third dam, and the need to add storage permits with the Texas Commission on Environmental Quality (TCEQ).

Why it matters: The city’s two existing storage permits total about 700 acre‑feet (383 acre‑feet for Towne Lake under a 1914 permit and 317 acre‑feet for Robinson Park under a 1956 permit). Staff said recent bathymetric work showed both gains and losses in stored volume since 2011 and that raising dam heights or building new storage would be the most certain way to increase available water. The proposals, staff said, also open access to grants and water‑contract opportunities but require long lead times and substantial upfront work.

City staff summarized recent storage surveys and dredging outcomes, showing that combined stored volumes rose between 2011 and 2022 but declined slightly in a 2025 survey. Staff said Towne Lake’s storage when measured in 2011 (without flashboards) was about 272 acre‑feet; adding flashboards increased Towne Lake to about 459 acre‑feet. Combined storage in 2011 was about 703 acre‑feet (close to permitted totals). Staff reported net gains of about 540 acre‑feet from 2011 to 2022 (296 acre‑feet at Towne Lake and 244 acre‑feet at Robinson Park), then a combined loss of about 60 acre‑feet in the most recent survey.

Staff described options and estimated costs. An engineer’s opinion of probable construction cost for raising the heights of both dams was presented as roughly $5.2 million to $9.5 million (construction cost only). A proposed third dam was estimated at about $14 million to $23 million (construction cost only). Staff cautioned those cost ranges do not include engineering design, permitting, environmental studies, easement acquisition, geotechnical investigations or future operation and maintenance costs.

Staff said continuing dredging and bathymetric surveys will remain important. They described evaporation as a continuing loss from surface storage and explained that, for example, a 400‑acre‑foot off‑channel reservoir would require roughly 40 acres at 10 feet deep and could lose substantial volume to evaporation in summer months; staff used an example evaporation loss of about 275 gallons per day per acre during peak months.

Staff also outlined regulatory and technical steps needed before construction: an updated hydrologic and hydraulic analysis, FEMA coordination on flood‑plain impacts, TCEQ permit amendments for storage changes and, potentially, environmental impact studies. Staff said dam stability assessments and outlet‑works repairs would be required as a minimum to make existing dams last another century. Bruce Nichols, who inspected the dams in 2023, was cited during the presentation as describing City Lake Dam’s condition as “fair to good” and Robinson Park Dam as “poor to good.”

Funding and next steps: Staff reported receipt of a Scripps Foundation package — described as a $3.5 million grant spread over three years plus a $3.5 million low‑interest loan at about 2.25% over 30 years — that the city may use only for dam improvements. Staff said the loan proceeds have been deposited and are drawing interest; staff suggested interest earned could be used for project cost increases or as match funding for other grants. The city also has an application filed with the Lower Colorado River Authority (LCRA) seeking a firm water yield of 487 acre‑feet; staff said that contract, if finalized, would allow the city to apply for LCRA grants and resident/business rebate programs.

Timing and constraints: City staff said the permitting, engineering and environmental work means actual construction or breaking ground is unlikely within less than four years. Staff listed a set of near‑term tasks: finalize the LCRA contract; update drought contingency and water conservation plans; meet with a water‑rights attorney about amending storage rights; coordinate with TCEQ and FEMA on hazard reclassification and permit amendments; and pursue state and federal funding opportunities.

Public comment and council direction: Members of the public and council asked questions about alternatives — notably horizontal and “gooey” wells (groundwater wells influenced by surface water) — and about the cost/benefit tradeoffs of dam raising versus drilling. Staff reiterated that dredging and flashboards have a proven short‑term benefit and that dam‑raising or a new dam provide a firm, measurable increase in storage, while wells and horizontal drilling carry uncertain production rates and would require additional permitting, treatment and pipeline infrastructure.

Ending: Staff emphasized that the city needs to continue routine bathymetric surveys, dredging and dam maintenance while pursuing longer‑term permit and construction options. Board members and staff said they will continue technical work, seek funding opportunities and return with more refined cost estimates and permit requirements before any construction decisions are made.